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Introduction: the “Assessment of Spondyloarthritis International Society Health Index” (ASASHI) questionnaire was developed to globally measure function and health status in patients with spondyloarthritis (SpA). Cut-off points have been proposed to determine different health states that were poorly evaluated in real-life patients. Objectives: to describe the health status measured by ASAS-HI in Argentine patients with axial SpA (AxSpA) and peripheral SpA (SpAp) in daily practice and to evaluate the factors associated with poor health. Materials and methods: cross-sectional, analytical and multicenter study. Patients with SpAax and SpAp were consecutively included according to ASAS criteria, from 15 Argentine centers. Statistical analysis: descriptive statistics, bivariate and multivariate analysis (multiple logistic regression) were performed to evaluate the factors associated with poor health status (ASAS-HI≥12). To analyze the construct validity of the tool, Spearman correlation was performed between the ASAS-HI and other disease evaluation parameters. Results: 274 patients with SpA were included, with a mean age of 49 (± 14) years and a median duration of the disease of 62 months (p25-75: 24-135), 155 (56.6%) were male, 129 patients (47%) with AxSpA and 145 (52.9%) SpAp. According to the ASAS-HI, 119 patients (43.4%) had good health, 117 (42.7%) had moderate health and 38 (13.9%) had poor health. In patients with SpAp, the mean ASAS-HI value was 7 (p25-75: 3-10). The ASAS-HI positively correlated with: DAS28: rho: 0.5 (p

BackgroundEarly arthritis is an inflammatory disease with the potential to progress to persistent arthritis, such as established Rheumatoid Arthritis (RA) or other articular disease, to resolve spontaneously or remain undifferentiated for indefinite periods of time.ObjectivesTo identify predictors of persistent RA after 12 months follow up in the Argentinean early arthritis clinic (CONAART).MethodsWe conducted an observational, prospective longitudinal study, including patients with early arthritis (at least 1 swollen joint with Sociodemographic and clinical data and characteristics of the disease were recorded at baseline, at 3, 6 and 12 months. After 1 year of follow-up, each patient was classified according to diagnosis: self-limited arthritis, persistent non-erosive arthritis, or persistent erosive arthritis.The association between the different predictors of diagnosis at 12 months was evaluated using multiple logistic regression, adjusted by potential confounders. Rheumatoid Factor (RF) and Anti Citrullinated Peptide Antibodies (ACPA) were included in separate models in order to avoid multicollinearity. A value of pResultsWe included 839 patients, 83% females, mean age of 57±14 years and mean disease duration of 8.2±6.2 months; 67.5% were rheumatoid factor positive and 59% ACPA positive. Disease characteristics at baseline were DAS28 5.1±1.4, swollen joints 6±5, erythrocyte sedimentation rate (ESR) 34±25 mm/h, C Reactive Protein (CRP) 4±6 and Health Assessment Questionnaire-Argentinean (HAQ-A) 1.2±0.8.After 12 months follow up, 11% of the patients were diagnosed as self-limited disease, whereas 89% were diagnosed as persistent disease. For the persistent disease, 34% presented radiograph erosions and therefore were catalogued as persistent erosive disease.The seropositivity for both, RF and ACPA, together with baseline DAS28, were the variables independently associated with the development of persistent disease at 12 months. [Model 1a: RF OR 2.33 (95% CI 1.44, 3.78) and DAS28 1.27 (1.06, 1.52); Model 2a: ACPA 2.61 (1.38, 4.93) and DAS28 1.59 (1.24, 2.04)]. (Table 1).Table 1.Predictors of Persistent Rheumatoid Arthritis at 12 monthsOutcomesPersistent RAPersistent RAPersistent RAPersistent RAOR (95 IC)OR (95 IC)OR (95 IC)OR (95 IC)Model 1aModel 1bModel 2aModel 2bn708708507507Age (years)0.99 (0.98, 1.01)0.99 (0.98, 1.01)0.99 (0.97, 1.01)0.99 (0.97, 1.01)Female gender1.06 (0.57, 2.00)1.06 (0.56, 1.99)0.72 (0.30, 1.71)0.72 (0.30, 1.70)RF positive2.33 (1.44, 3.78)***2.45 (1.52, 3.98)***--ACPA positive--2.61 (1.38, 4.93)**2.63 (1.39, 4.98)**DAS28 at baseline1.27 (1.06, 1.52)**1.59 (1.24, 2.04)***Categorical DAS28 MDA (vs LDA)-1.81 (0.85, 3.86)^-2.86 (1.68, 6.99)* HDA (vs LDA)-2.83 (1.30, 6.15)^-6.39 (2.42, 16.82)***^ p* p** p*** pRF, Rheumatoid Factor; ACPA, Anti Citrullinates Protein Antigen; DAS28, Disease activity Score-28; LDA, low disease activity; MDA, moderate disease activity; HDA, high disease activity.In the patient prediction model, it can be observed that a patient with female gender, ACPA negative, and a low activity at baseline (DAS28 Figure 1.Matrix prediction model. Probability of diagnosis of Persistent Rheumatoid Arthritis after 12 months of follow-up. Colors represents predictive probability of achieving the outcome as follow: grey: 0-69.9%; blue: 70.0-89.9%; purple: 90.0-100%.DAS28, Disease Activity Score 28; LDA, low disease activity; MDA, Moderate Disease Activity; HDA, High Disease Activity.ConclusionPredictors of persistent arthritis after 12 months of follow up since AT diagnosis were RF and ACPA seropositivity and higher baseline disease activity level.Disclosure of InterestsNone declared.

Treatment persistence is a surrogate marker for long-term treatment success. Objective: To assess the persistence of the biological agents used for treatment of patients with rheumatoid arthritis (RA) over 5 years period and to determine the main causes associated with persistence or discontinuation. Material and methods: A systematic literature review (SLR) was carried out, according to PRISMA recommendations, including Pubmed, Cochrane and Lilacs databases, and studies presented at the ACR, EULAR, PANLAR congresses (2018/2019) until January 2020. Two independent reviewers evaluated the identified publications, by title and abstract and full text, according to PICO methodology. Eligibility criteria were: studies including RA patients ≥ 18 years, treated with biological agents, which measured persistence/ discontinuation for a period of time equal to or greater than 5 years and who were in English or Spanish language. In the case of lack of agreement between the two reviewers, a third reviewer was consulted. The extracted information was analyzed using descriptive statistics, an average percentage of persistence for each biological agent at 5 years was calculated. Results: 56 articles were selected after removal of duplicates and exclusion by title/abs-tract, and by full text. Long-term extension phase of randomized controlled studies were 13, another 15 retrospective cohorts, 18 prospective cohorts and 10 retro-prospective cohorts and corresponded to a total of 72177 (range: 79-10396) patients with RA, with a mean age of 53.8 years ± 12.1, 78.2% female and an average RA disease duration of 9.7 years ± 8.4. In 33.9% of the studies, biological therapy was combined with conventional disease modifying anti-rheumatic drugs (c-DMARDs), in 3.6% monotherapy, 48.2% both modalities, and in 14.3% not reported. One study was in the 1st line (methotrexate näive), 29 studies in 2nd line (inadequate response to MTX and/or c-DMARDs), 5 in 3rd line (inadequate response to biological b-DMARDs), 12 in ≥2nd therapeutic line and in 9 studies did not specify this condition. In 30 studies which evaluated the 2nd therapeutic line, the highest persistence corresponded to tocilizumab (TCZ) 66.41% (95% CI 57.8-79.94), abatacept (ABA) 57.91% (95% CI 50.96-64.87) and golimumab (GOL) 54.38% (95% CI 48.58-60.19). In 10 studies, in which b-DMARD had been analyzed in 3rd therapeutic line, highest retention rates corresponded to rituximab (RTX) 61.19% (95% CI 57.53-66.22) and TCZ 61.1% (95% CI 58.81-63.32). Among studies that evaluated predictors, the most frequently associated with higher survival were: combined treatment with c-DMARD, etanercept versus infliximab and adalimumab and 2nd line of treatment vs. 3rd or 4th line whereas those associated with lower survival rates were: greater use of steroids, higher baseline disease activity, and female gender. Conclusions: In this SLR, the 5-year persistence of b-DMARD in patients with inadequa-te response to DMARs-c and DMARs-b was numerically greater for non-TNFi agents. And among TNFi, GOL presented a higher retention in 2nd therapeutic line.

BackgroundCurrently there is little information on the efficacy and safety of SARS-CoV-2 vaccination in patients with immune-mediated diseases and/or under immunosuppressive treatment in our country, where different types of vaccines and mix regimens are used. For this reason, the Argentine Society of Rheumatology (SAR) with the Argentine Society of Psoriasis (SOARPSO) set out to develop a national register of patients with rheumatic and immune-mediated inflammatory diseases (IMIDs) who have received a SARS-CoV-2 vaccine in order to assess their efficacy and safety in this population.ObjectivesTo assess SARS-CoV-2 vaccine efficacy and safety in patients with rheumatic and IMIDs.MethodsSAR-CoVAC is a national, multicenter and observational registry. Adult patients with a diagnosis of rheumatic or IMIDs who have been vaccinated for SARS-CoV-2 were consecutively included between June 1st and September 17th, 2021. Sociodemographic data, comorbidities, underlying rheumatic or IMIDs, treatments received and their modification prior to vaccination and history of SARS-CoV-2 infection were recorded. In addition, the date and place of vaccination, type of vaccine applied, scheme and indication will be registered. Finally, adverse events (AE), as well as SARS-CoV-2 infection after the application of the vaccine were documentedResultsA total of 1234 patients were included, 79% were female, with a mean age of 57.8 (SD 14.1) years. The most frequent diseases were rheumatoid arthritis (41.2%), osteoarthritis (14.5%), psoriasis (12.7%) and spondyloarthritis (12.3%). Most of them were in remission (28.5%) and low disease activity (41.4%). At the time of vaccination, 21% were receiving glucocorticoid treatment, 35.7% methotrexate, 29.7% biological (b) Disease Modifying Anti-Rheumatic Drugs (DMARDs) and 5.4% JAK inhibitors. Before vaccine application 16.9% had had a SARS-CoV-2 infection.Regarding the first dose of the vaccine, the most of the patients (51.1%) received Gam-COVID-Vac, followed by ChAdOx1 nCoV-19 (32.8%) and BBIBP-CorV (14.5%). In a lesser proportion, BNT162b2 (0.6%), Ad26.COV2.S (0.2%) and CoronaVac (0.2%) vaccines were used. Almost half of them (48.8%) completed the scheme, 12.5% were mix regimenes, the most frequent being Gam-COVID-Vac / mRNA-1273. The median time between doses was 51days (IQR 53).More than a quarter (25.9%) of the patients reported at least one AE after the first dose and 15.9% after the second. The flu-like syndrome and local hypersensitivity were the most frequent manifestations. There was one case of mild anaphylaxis. No patient was hospitalized. Altogether, the incidence of AE was 246.5 events/1000 doses. BBIBP-CorV presented significantly lower incidence of AE in comparison with the other types of vaccines. (118.5 events/1000 doses, pRegarding efficacy, 63 events of SARS-CoV-2 infection were reported after vaccination, 19% occurred before 14 days post-vaccination, 57.1% after the first dose (>14 days) and 23.8% after the second. In most cases (85.9%) the infection was asymptomatic or had an outpatient course and 2 died due to COVID-19.ConclusionIn this national cohort of patients with rheumatic and IMIDs vaccinated for SARS-CoV-2, the most widely used vaccines were Gam-COVID-Vac and ChAdOx1 nCoV-19, approximately half completed the schedule and in most cases homologously. A quarter of the patients presented some AE, while 5.1% presented SARS-CoV-2 infection after vaccination, in most cases mild.Disclosure of InterestsNone declared

BackgroundPatients with rheumatic diseases (RD) have been excluded from SARS-CoV-2 vaccine trials, though data appear to show safety and efficacy, mostly evidence remains in mRNA vaccines. In our country, adenovirus-vector, inactivated and heterologous scheme vaccines are frequently used.ObjectivesTo describe the safety of SARS-CoV-2 vaccines in patients with RD from the national registry SAR-CoVAC and to assess sociodemographic and clinical factors associated to AE and disease flares after vaccination.MethodsAdult patients with RD who have been vaccinated for SARS-CoV-2 from de Argentine Society of Rheumatology Vaccine Registry (SAR-CoVAC) were consecutively included between June 1st and December 21st, 2021, This is a national multicentric observational registry that includes patients that have received at least one dose of any SARS-CoV-2 available vaccines in Argentina. Data is voluntarily collected by the treating physician. Naranjo scale was use to assess the association between the AE and vaccination.Homologous and heterologous schedules were defined according to whether both vaccines received were the same or different, respectively. Descriptive statics, Chi2 test, Fischer test, T test, ANOVA and multivariate regression logistic model were used.ResultsA total of 1679 patients, with 2795 SARS-CoV-2 vaccine doses were included. Vaccines more frequently used were: Gam-COVID-Vac (1227 doses, 44%), ChAdOx1 nCov-19 (872 doses, 31%), BBIBP-CorV (482 doses, 17%) and mRAN-1273 (172 doses, 6%). Altogether, 510 EA were experienced by 449 (27%) patients. Pseudo-flu syndrome was the most frequent (11%), followed by injection site reaction (7%). They were significantly more frequent after the first dose in comparison to the second one (13% vs 7% and 9% vs 5%, respectively, pTotal incidence of EA was 182.5 events/10 00 doses, it was significantly lower for BBIBP-CorV (105.9 events/1000 dosis, pPatients with AE were younger [mean 55 years (SD 14) vs 59 years (SD 14), p In the multivariable analysis, mRAN-1273 and ChAdOx1 nCov-19 were associated with AE, while BBIBP-CorV with lower probability of having one. (Figure 1)Figure 1.Variables associated with the development of AE. Multivariate logistic regression modelConclusionThe incidence of AE was 1825 events/1000 doses, were significantly higher for mRAN-1273 and ChAdOx1 nCov-19 and lower for BBIBP-CorV. Most common AE was pseudo-flu syndrome. Female sex, being younger, higher education level, ChAdOx1 nCov-19 and mRAN-1273 vaccines, the use of methotrexate and antimalarials were related of EA in patients with RD.References[1]Sattui SE et al. Early experience of COVID-19 vaccination in adults with systemic rheumatic diseases: results from the COVID-19 Global Rheumatology Alliance Vaccine Survey. RMD Open 2021;7.Disclosure of InterestsNone declared

BackgroundVaccination for COVID-19 is an essential tool to fight the pandemic. Evidence suggests that patients with immune mediated inflammatory diseases (IMIDs) have less response. The application of a booster shot is a strategy that has been implemented in this population, however there is scarce information about its efficacy.ObjectivesTo assess the humoral and cellular immune response after a third dose of SARS-CoV-2 vaccine in patients with rheumatoid arthritis (RA) with undetectable antibodies titles after primary regimen of two doses.MethodsObservational study. Patients with RA (ACR/EULAR 2010 criteria) from two rheumatology centers, ≥18 years old, with no seroconversion after two doses of SARS-CoV-2 vaccine, who received a third dose of either mRNA or vector-based vaccines (BNT162b2 or ChAdOx1 nCoV-19) were included. Anti-SARS-CoV-2 IgG antibodies, neutralising activity and T cell responses were assessed between 21 and 40 days after the third dose. Sociodemographic data, comorbidities, treatment, vaccine applied and the presence of adverse events (AE) were recorded. Statistical analysis: descriptive analysis. Chi2 or Fischer test and T test.ResultsA total of 21 non-responder patients were included, all of them females with a mean age of 63.7 years (SD 11,6) and mean disease duration of 15.8 years (SD 8). Most of them (81%) reported comorbidities, being the most frequent arterial hypertension, obesity and dyslipidemia. At vaccination time, 6 (28.6%) were receiving glucocorticoids, 3 of them ≥10 mg/day, 17 c-DMARDs (methotrexate 57.1%) and 18 (85.1%) b-DMARDs, 6 abatacept (ABT) and 4 rituximab (RTX).Regarding the primary vaccination regimen, 13 (61.9%) received two doses of BBIBP-CorV, 3 (14.3%) Gam-COVID-Vac, 3 (14.3%) ChAdOx1 nCoV-19 and 2 (9.5%) a mix regimen of Gam-COVID-Vac/mRNA-1273. The majority (95.2%) received BNT162b2 vaccine and only one of them ChAdOx1 nCoV-19, with a mean time between the second and third dose of 151,4 days (SD 46,4). After the third dose, 90.5% of the patients presented detectable anti-SARS-CoV-2 IgG and 76.2% presented neutralizing activity. The median of neutralizing antibodies titers was 1/12 (IQR 1/7-1/48). Both patients who did not present detectable antibodies were obese, recieved BBIBP-CorV during the primary regimen and BNT162b2 as the third dose, one of them was taking methotrexate and ABT and the other one RTX. Compared to other treatments, ABT and RTX was associated with no neutralizing activity in 4 (80%) patients and lower titers of neutralizing antibodies [median 1/3 (IQR 0-1/20) vs median 1/8 (IQR 1/4-1/128), p=0.197].A T-cell response was present in 41.2% of all patients after the second dose, increasing to 75% after the third dose. The use of ABT was associated with a lower frequency of T-cell response (80% vs 20%, p=0.014).Sixteen (76.1%) patients reported at least one AE, 66.7% injection site reaction and 25% flu-like syndrome.ConclusionIn this RA cohort who failed to seroconvert after two doses of SARS-CoV-2 vaccine, 90.5% presented detectable anti-SARS-CoV-2 IgG and 75% T-cell responce after a third dose. The use of ABT was associated with a lower frequency of T-cell response. This data highlights the importance of a third vaccine in this group of patients.Disclosure of InterestsNone declared

BackgroundPatients with rheumatic diseases (RD) have been excluded from SARS-CoV-2 vaccine trials. Though data appear to show safety and efficacy, mostly evidence remains in mRNA vaccines. However in our country, adenovirus and inactivated vaccines, as well as heterologous schemes are frequently used.ObjectivesTo describe clinical characteristics and outcomes of SARS-CoV-2 infection after vaccination in patients with RD from de the SAR-CoVAC registry and to compare them with patients who got infected before vaccination. Additionally, factors associated with COVID-19 unfavorable outcome were assessed.MethodsAdult patients with RD who have been vaccinated for SARS-CoV-2 were consecutively included between June 1st and December 21st, 2021. Confirmed SARS-CoV-2 infection (RT-PCR o serology) was reported by the treated physician. Infection after an incomplete scheme was defined when the event was diagnosed at least 14 days after first dose; and after a complete scheme when it occurred > 14 days after second dose. Homologous scheme is defined by two same doses of vaccine and heterologous by two different doses. Patients with previous SARS-CoV-2 infection were excluded. To compare SARS-CoV-2 infection characteristics in not vaccinated patients, subjects from the SAR-COVID registry, which includes patients with RD and SARS-CoV-2 infection, were matched 2:1 by gender, age and RD.WHO-Ordinal Scale ≥5 was used to define unfavorable infection outcome. Descriptive statics, Chi2 test, Fischer test, T test and ANOVA were used.ResultsA total of 1350 patients from the SAR COVAC registry were included, 67 (5%) presented SARS-CoV-2 infection after vaccination. The later were mostly (72%) females with a mean age of 57 (SD 15) years old. The most frequent RD were rheumatoid arthritis (41%), psoriatic arthritis (12%) and systemic lupus erythematosus (10%). At vaccination, most of them (75%) had low disease activity or remission, 19% were taking steroids, 39% methotrexate, 27% bDMARDs and 6% JAK inhibitors.A total of 11 (16%) patients had SARS-CoV-2 infection After vaccination only 8 (12%) of the patients who got infected had an unfavorable course, 88% of them following an incomplete scheme (5 received Gam-COVID-Vac, 1 ChAdOx1 nCov-19 and 1 BBIBP-CorV) and one subject after a complete homologous Gam-COVID-Vac scheme. Having an unfavorable outcome of SARS-CoV-2 infection was associated to: male gender [63% vs 24%, p=0.036], older age [mean 70 years (SD 7) vs 55 years (SD 15), p=0.005], being Caucasian [100% vs 54%, p=0.018], higher education [mean 17 years (SD 4) vs 12 years (SD 4), p=0.010], the presence of comorbidities [100% vs 39%, p=0.001, having pulmonary disease [37% vs 5%, p=0.019], dyslipidemia [63% vs 17%, p=0.011] and arterial hypertension [63% vs 24%, p=0.036], RD, treatments, disease activity and types of vaccines received were comparable between groups.When comparing patients with and without vaccination prior SARS-CoV-2 infection, those who received at least one dose of vaccine had less frequently severe COVID-19 (12% vs 24%, p=0.067) and presented lower mortality due to COVID-19 (3% vs 6%, p=0.498). However these differences did not reach statistical significance.ConclusionIn the SAR-CoVAC registry 5% of the patients had SARS-CoV-2 infection after vaccination, most of them mild and 25% after a complete scheme. Any vaccine was associated with severe COVID-19. When comparing with non-vaccinated patients, those with at least one dose, had less frequently severe disease and died due COVID-19.Disclosure of InterestsNone declared

BackgroundHigh disease activity, treatment with glucocorticoids (GC) and rituximab (RTX), have been related to worse outcomes of COVID-19.ObjectivesTo assess the clinical characteristics and severity of the SARS-CoV-2 infection in patients with rheumatoid arthritis (RA) included in the SAR-COVID registry and to identify factors associated with poor outcomes.MethodsSAR-COVID is a national, longitudinal and observational registry. Patients of ≥18 years old, with diagnosis of RA (ACR-EULAR criteria 2010) who had confirmed SARS-CoV-2 infection (RT-PCR or positive serology) were included between 13-8-20 and 31-7-21. Sociodemographic and clinical data, comorbidities, disease activity and treatment at the moment of the SARS-CoV-2 infection were collected. Additionally, infection symptoms, complications, medical interventions and treatments for COVID-19 were registered. Infection severity was assessed using the WHO-ordinal scale (WHO-OS)1. A cut-off value of ≥5 identified patients with severe COVID-19 and those who died.Statistical analysis: Descriptive statistics. Chi2 or Fischer test, Student T test or Mann-Whitney and Kruskal Wallis or ANOVA, as appropriate. Multiple logistic regression model.ResultsA total of 801 patients were included, with a mean age of 53.1 ± 12.9 years, most of them were female (84.5%) and the median (m) disease duration was 8 years (IQR 4-14). One third were in remission and 46.4% had comorbidities, being the most frequent, hypertension (26.9 %), dyslipidemia (13.5 %), obesity (13.4 %) and diabetes (8.9%). Moreover, 3.2% had interstitial lung disease (ILD) associated with RA. At SARS-CoV-2 diagnosis, 42.5% were receiving glucocorticoids (GC), 73.9% conventional (c) disease modifying antirheumatic drugs (DMARD), 24% biologic (b) DMARD and 9.1% targeted synthetic (ts) DMARD. Among bDMARD, the most frequently used were TNF inhibitors (17%), followed by abatacept (2.8%), IL-6 inhibitors (2.4%) and rituximab (RTX) (2.1%). During the SARS-CoV-2 infection, 95.8% had symptoms, 27% required hospitalization, 7.9% presented complications and 4.4% died due to COVID-19. Severe disease and death (WHO-OS≥5) was present in 7.5% of the patients. They were older (62.9±12.5 vs 52.2±12.7, pFigure 1.Factors associated with severe disease and death due to COVID-19 (WHO-OS≥5) in patients with rheumatoid arthritis. Multivariable analysis. (ref.: reference; PDN: prednisone; OR: odds ratio; CI: confidence interval)ConclusionTreatment with RTX and GC, as well as older age, the presence of diabetes and ILD were associated with poor COVID-19 outcomes in this national cohort of patients with RA. Older patients and those taking GC had a higher mortality rate.References[1]World Health Organization coronavirus disease (COVID-19) Therapeutic Trial Synopsis Draft 2020.Disclosure of InterestsNone declared

The aspartate aminotransferase (SGOT) and alanine aminotransferase (SGPT) are sensitive indicators of liver damage. While the TSGOT is also found in other organs, the SGPT is considered an enzyme specific liver. However, some authors state that the TGP can rise also in cases of muscle injury. Furthermore, there are reports in the literature suggesting the association of idiopathic inflammatory myopathies (IIM) with viral hepatitis.To determine the frequency of abnormal liver function tests in patients with idiopathic inflammatory myopathies, evaluate possible associationsto liver diseases, determine its relationship with elevation of muscle enzymes and whether these patients have particular clinical and / or serological characteristics.Consecutive patients older than 16 years diagnosed with DM / PM according to Bohan and Peter criteria during 1999-2000 were included. Patients with other connective tissue disease (CTD) were excluded. Demographic data were recorded, characteristics of the disease, laboratory data and elevated liver enzymes and muscle during the course of the disease. Serologic tests were performed for viral hepatitis B and C and confirmatory tests (HBV-DNA and HCV-RNA by PCR). Autoantibodies were determined: ANA (antinuclear antibody) by Hep II, ASMA (anti smooth muscle antibody), AMA (anti-mitochondrial antibodies) and LKM (Liver Kidney Microsomal) by mouse wound, MSA (myositis-specific antibodies) by ELISA. Patients who had abnormal liver tests underwent hepatic ultrasonography. For statistical analysis, descriptive statistics, categorical variables were compared by Fisher's exact test.We included 27 patients, of whom 22 had sufficient data for analysis. Mean age 47.95 years ± 16, 18 female (81.8%) and mean disease duration 8.09 ± 5.6 years. With regard to liver enzymes, 14/22 patients (63.3%) had elevated SGPT and 11/22 (50%) elevated SGOT, 10 of these patients also had elevated SGPT concomitantly. In the 10/15 (66.7%) abdominal ultrasonography showed abnormalities, 8 patients had liver hyperechogenicity, 4 cholelithiasis and 1 patient hepatomegaly. No patient bearing of HBV or HCV. The 8 patients with liver hyperechogenicity matched the 8 patients with isolated elevation of SGPT/SGOT. As for the 10 patients who had both elevated liver enzymes (SGPT and SGOT), only one case could be explained by liver disease (patient ASMA +). However in the 15 cases studied, elevations of SGPT and / or SGOT coincided with outbreaks of myositis,findingconcomitant apparent liver disease in only 9 of them.In this study, elevated transaminases, including the TGP, was observed concomitantly with the activity of myositis. Approximately half of these cases could not be associated with coexisting liver disease, which could be attributed to injury to muscle secondary to inflammatory myopathy.

The ability of native and chemically modified bovine serum albumin (BSA) to maintain normal pulmonary microvascular permeability was tested in "bloodless," fluorocarbon emulsion exchange transfused rats. Wet-to-dry weight ratios (W/D) of whole lung and morphometric estimates of the amount of ferritin transported to basement membrane were used to assess changes in water flux and macromolecular transport, respectively. Native and modified BSA in capillary walls were localized by immunogold techniques. Arginine residues of BSA were blocked with cyclohexanedione (CHD-BSA), and lysine residues were modified either by succinylation (Succ-BSA) or reductive methylation. Succinylation and CHD modification of BSA caused alterations in antigenicity and trypsin sensitivity; succinylation reduced the isoelectric point (pI). Whereas administration of either CHD-BSA or Succ-BSA increased the W/D, transport of ferritin to basement membrane was greater in the presence of Succ-BSA than CHD-BSA. By contrast, infusion of reductively methylated BSA in which modified lysines altered neither antigenicity nor pI, resulted in a W/D and amount of ferritin in basement membranes comparable to that of BSA. Binding of CHD-BSA and Succ-BSA to endothelial glycocalyx appeared to be reduced relative to native BSA and reductively methlyated BSA. The lowered pI of Succ-BSA may have contributed to its reduced binding; reductively methylated BSA with an unaltered pI was present in the glycocalyx. These data are consistent with a role for positively charged arginine residues in the interaction of albumin with the glycocalyx. The W/D of animals perfused with BSA was higher than those reported for rats perfused with complete rat serum proteins. This is consistent with the notion that serum factors, in addition to albumin, are required to maintain normal microvascular permeability.

Tight junctions (TJ) govern ion and solute diffusion through the paracellular space (gate function), and restrict mixing of membrane proteins and lipids between membrane domains (fence function) of polarized epithelial cells. We examined roles of the RhoA and Rac1 GTPases in regulating TJ structure and function in MDCK cells using the tetracycline repressible transactivator to regulate RhoAV14, RhoAN19, Rac1V12, and Rac1N17 expression. Both constitutively active and dominant negative RhoA or Rac1 perturbed TJ gate function (transepithelial electrical resistance, tracer diffusion) in a dose-dependent and reversible manner. Freeze-fracture EM and immunofluoresence microscopy revealed abnormal TJ strand morphology and protein (occludin, ZO-1) localization in RhoAV14 and Rac1V12 cells. However, TJ strand morphology and protein localization appeared normal in RhoAN19 and Rac1N17 cells. All mutant GTPases disrupted the fence function of the TJ (interdomain diffusion of a fluorescent lipid), but targeting and organization of a membrane protein in the apical membrane were unaffected. Expression levels and protein complexes of occludin and ZO-1 appeared normal in all mutant cells, although ZO-1 was more readily solubilized from RhoAV14-expressing cells with Triton X-100. These results show that RhoA and Rac1 regulate gate and fence functions of the TJ, and play a role in the spatial organization of TJ proteins at the apex of the lateral membrane.

Effros, R. M., C. Darin, E. R. Jacobs, R. A. Rogers, G. Krenz, and E. E. Schneeberger. Water transport and the distribution of aquaporin-1 in pulmonary air spaces. J. Appl. Physiol. 83(3): 1002–1016, 1997.—Recent evidence suggests that water transport between the pulmonary vasculature and air spaces can be inhibited by HgCl2, an agent that inhibits water channels (aquaporin-1 and -5) of cell membranes. In the present study of isolated rat lungs, clearances of labeled (3HOH) and unlabeled water were compared after instillation of hypotonic or hypertonic solutions into the air spaces or injection of a hypotonic bolus into the pulmonary artery. The clearance of3HOH between the air spaces and perfusate after intratracheal instillation and from the vasculature to the tissues after pulmonary arterial injections was invariably greater than that of unlabeled water, indicating that osmotically driven transport of water is limited by permeability of the tissue barriers rather than the rate of perfusion. Exposure to 0.5 mM HgCl2in the perfusate and air-space solution reduced the product of the filtration coefficient and surface area ( PfS) of water from the air spaces to the perfusate by 28% after instillation of water into the trachea. In contrast, perfusion of 0.5 mM HgCl2in air-filled lungs reduced PfSof the endothelium by 86% after injections into the pulmonary artery, suggesting that much of the action of this inhibitor is on the endothelial surfaces. Confocal laser scanning microscopy demonstrated that aquaporin-1 is on mouse pulmonary endothelium. No aquaporin-1 was found on alveolar type I cells with immunogold transmission electron microscopy, but small amounts were present on some type II cells.

In the presence of Ca2+, application of trypsin to the basolateral surface of confluent MDCK cell monolayers with formed tight junctions (TJ), induces the formation of basolaterally oriented aberrant TJ strands. Induction of aberrant TJ strands is accompanied by an increase in transepithelial electrical resistance (TER), up to 90%, which upon addition of trypsin inhibitor is maintained for up to 1 h. Thereafter TER returns slowly to baseline values. Under similar conditions, application of trypsin to the apical surface has little or no effect on either TER or the number of aberrant TJ strands. Confocal microscopy of monolayers, immunostained for ZO-1, revealed that this TJ associated cytoplasmic protein, extended below the TJ along the basolateral surface following brief exposure to trypsin. Removing Ca2+ after treatment of the monolayer with basolaterally applied trypsin resulted, after 20 min, in the increased partitioning of TJ particles onto the E fracture face, of both normal and aberrant TJ strands. Like the TJ strands themselves, therefore, aberrant strands may be linked to cytoskeletal elements. Aberrant TJ strands do not form when monolayers, maintained in low Ca2+ medium, are exposed to trypsin, suggesting that under these conditions TJ precursors, and/or trypsin-sensitive proteins regulating TJ strand assembly, are sequestered in a vesicular compartment that is inaccessible to exogenous trypsin. Prolonged exposure of the apical surface of an established, polarized epithelium with intact TJ to trypsin, had little effect on TJ integrity and did not induce aberrant strands.

Several laboratories, including our own, have previously shown that the B7 antigen, a glycoprotein expressed on activated B cells, macrophages and dendritic cells, can provide a potent costimulatory signal for peripheral murine T lymphocytes. In the present report we have analysed the expression and function of B7 in the murine thymus. The expression of B7 was demonstrated histochemically. B7-expressing cells were present in the thymic medulla but virtually absent from the cortex. Further analysis by immunofluorescence and flow fluorocytometry revealed that the B7-positive cells also expressed major histocompatibility complex (MHC) class II molecules. Both epithelial and dendritic cells expressed the B7 antigen. Finally, although we have demonstrated expression of mB7 in the murine thymus, we have been unable to detect a function for this antigen in this organ. The implications of these findings are discussed.

When the protective structural and functional barriers of the lung are breached, immune responses must be generated in order to contain invading micro-organisms. This requires the presence of accessory cells capable of phagocytosing and presenting immunogenic peptides to either naive or sensitized T cells. In contrast to dendritic cells (DC) present in the airway epithelium, those within the lung parenchyma do not readily engulf particulates and, therefore, other mechanisms must account for their apparent ability to present immunogenic peptides derived from micro-organisms. The purpose of the present study was to determine the extent to which interstitial macrophages (IM) interact with lung DC to process and present antigenic peptides, derived from particulate, heat-killed Listeria monocytogenes (HKL), to HKL-immune T cells. Results show that highly purified Ia- lung IM avidly phagocytose fluorescent-labelled HKL, but they do not present antigen to primed T cells. Their ability to present antigen is only modestly increased following interferon-gamma (IFN-gamma) stimulation. Conversely, mature DC isolated from the lung interstitium do not phagocytose fluorescent-labelled HKL. In antigen presentation assays, however, addition of 10% (2.5 x 10(3)/ml) Ia- IM to DC and HKL results in a two- to threefold increase in antigen presentation by DC to HKL-immune T cells. Conditioned medium (CM), generated by 2.5 x 10(4)/ml IM induced to phagocytose HKL, when administered to DC and HKL-sensitized T cells without added intact HKL, resulted in brisk mitogenesis, a response that did not occur in T cells sensitized to an irrelevant antigen. Conditioned medium derived from larger numbers of IM was inhibitory. When IM phagocytosed inert polystyrene beads, the resulting CM induced modest T-cell mitogenesis, suggesting that small amounts of cytokines were released. The results indicate that in small numbers, IM augment DC function, in part, by the release of antigenic peptides which are then presented by DC to T cells. When present in numbers greater than 50% of DC, however, they inhibit DC function, probably due to the release of soluble inhibitors.

A substantial body of evidence indicates that the primary sensitization of naive T cells to inhaled antigens occurs in the regional lymph nodes, whereas secondary responses may be generated directly within lung tissue. Ia+ pulmonary dendritic cells are widely distributed within the rat lung where they can participate in the induction of the immune response to inhaled antigens. Recently, two subsets of Ia+ pulmonary dendritic cells have been distinguished based on their expression of Fc receptors (FcR), but little is known concerning their abilities to support the responses of naive or sensitized T cells. In order to address this question, pulmonary FcR+/- dendritic cells have been purified from enzymatic digests of Lewis rat lungs, based on their differential binding to heat-aggregated immunoglobulin. The FcR+/- dendritic cell subsets differed with respect to their light microscopic appearance and in their expression of non-specific esterase. Only the FcR+ subset was able to phagocytize latex beads and showed intracellular phagolysosomes by electron microscopy. Both of the FcR+/- subsets rapidly formed clusters with naive (OX-22+) and sensitized (OX-22-) T cells. However, the clusters yielded by the FcR+ subset were substantially smaller, possibly reflecting their diminished surface membrane expression of the intercellular adhesion molecule-1. The FcR+/- subsets were capable of presenting soluble and particulate antigens to OX-22- T cells. FcR+ cells were less effective than FcR- cells in promoting the proliferative response of OX-22+ T cells to concanavalin A and in the primary mixed leukocyte reaction. We conclude that the FcR+/- pulmonary dendritic cells differ in their abilities to support the responses of naive and sensitized T lymphocytes. This observation may have significance for how primary and secondary pulmonary cell-mediated immune responses are generated.

A role for lipids in the formation of tight junctions (TJ) has been proposed. Attempts to relate changes in whole cell phospholipid composition to the formation of TJs, however, have yielded equivocal results. The object in the present study was to relate changes in TJ of MDCK cells more specifically to alterations in plasma membrane lipids. Cholesterol, which resides primarily in the plasma membrane, was reduced by 25% after incubation of cell monolayers for 24 h in a low Ca2+ medium supplemented with (1-2 microM) Lovastatin, an inhibitor of hydroxymethylglutarylcoenzyme A (HMG-CoA) reductase. This was associated with a halving of the time required for Ca2+ to induce TJ formation as monitored by transepithelial electrical resistance (TER). [3H]Mannitol flux, and morphometric measurements made on freeze fracture replicas confirm that the effects on TER reflect changes in the characteristics of the paracellular pathway. Peak and steady state values of TER were also elevated over control values. The changes in cholesterol content and the time course for TJ assembly were apparent at levels of Lovastatin which do not affect prenylation of proteins, and were prevented if 5 mM mevalonate was present along with Lovastatin. Paradoxically, despite a decrease of approximately 1/3 in the Ca concentration required to yield maximum rates of TJ assembly, 45Ca2+ uptake was actually reduced after cholesterol depletion. The data suggest that cholesterol may modulate the properties of membrane proteins and/or phospholipids which interact with Ca2+, possibly on the exoplasmic leaflet, during TJ assembly.

The tight junction (TJ) is a dynamic structure that is controlled, in part, by the activity of the cytoskeleton. It has become abundantly clear that, in the presence of Ca2+, assembly of the TJ is the result of cellular interactions that trigger a complex cascade of biochemical events that ultimately lead to the formation of an organized network of TJ elements, the composition of which remains unknown. The TJ functions both as a barrier between two fluid compartments and, to a lesser extent, as a fence between apical and basolateral membrane domains. To meet the many physiological and pathological challenges to which epithelia and endothelia are subjected, the TJ must be capable of a rapid and coordinated response, which depends on complex regulatory mechanisms. The precise characterization of the mechanisms involved in the assembly and regulation of the TJ is an area of current active investigation. However, until the biochemical composition of this structure has been defined and its gene identified, the TJ will continue to be an elusive yet tantalizing challenge to the cell biologist.

The formation and maintenance of tight junctions as a barrier to the diffusion of ions and other water-soluble across epithelia is an energy-dependent process. The administration of N-formyl-hydroxyaminoacetic acid (Hadacidin), an analog of aspartate and a competitive inhibitor of adenylosuccinate synthetase, has been shown to inhibit the multiplication of clone 4 MDCK cells and concomitantly reduce the levels of ATP and cAMP (J. Cell. Physiol. 140, 186-194 (1989)). When added to mitotically quiescent confluent cultures of clone 4 MDCK cells, millimolar concentrations of Hadacidin inhibited the generation of transepithelial electrical resistance (TER). In such cultures passive Na+ permeability was similar to controls indicating that the effect of Hadacidin was not on the transcellular pathway. That these cells were viable was demonstrated by their ability to exclude Trypan Blue, and the fact that they remained competent to develop steady state TER upon removal of the inhibitor. Suppression of TER was completely reversed within 48 h of replacing the Hadacidin-supplemented medium with one containing aspartate. Adenosine, but not aspartate, when added simultaneously with the drug, obviated the latter's effect on TER. A mixture of dibutyryl cAMP (db-cAMP) and theophylline was only partially effective in overcoming the effects of Hadacidin on the development of TER and, in fact, markedly delayed its development in control cultures not treated with the drug. When monolayers with established steady state TER were exposed to Hadacidin, no change was noted during the first 24 h. By 48 h, however, TER had decreased to very low values.(ABSTRACT TRUNCATED AT 250 WORDS)

Monoclonal antibodies reactive with T cells, T cell subsets, B cells, monocytes, and natural killer cells were used to characterize the nature of mucosal lymphocytes in the human small intestine by application of the immunoperoxidase technique to tissue sections for light and electron microscopic examination. In addition, for comparison, peripheral blood mononuclear cells (PBL) were studied by immunoelectron microscopy. Most of the intraepithelial lymphocytes (IEL) were T cells (Leu-1+, T3+) and expressed the phenotype associated with cytotoxic/suppressor T cells (Leu-2a+, T8+). In contrast, a majority of T lymphocytes in the lamina propria expressed the phenotype associated with helper/inducer T cells (Leu-3a+, T4+). These observations confirm and extend the findings previously reported. In addition, a small number of cells in the lamina propria with the ultrastructural features of macrophages were found to react with anti-Leu-3a and anti-T4 antibodies. Although many IEL contained cytoplasmic granules and had ultrastructural features similar to those of circulating granular lymphocytes, none of these cells reacted with anti-Leu-7 (HNK-1), anti-T10, or anti-M1 antibodies. This suggests that IEL may not be related to circulating large granular lymphocytes, which are Leu-7+, T10+, M1+ and are associated with natural killer activity. Not only Leu-7+ PBL, but T8+, T4+, or T3+ mucosal lymphocytes or PBL also may contain cytoplasmic granules. Therefore, the cytoplasmic granules are not restricted to one cell type, in particular, to Leu-7+ cells.

Adherent synovial cells (ASC) were obtained from minced synovium from patients with rheumatoid arthritis by dissociating the lining cells from the extracellular matrix and dispersing them with proteases. These cells produce high levels of latent collagenase in primary culture. With passage of ASC, collagenase levels decrease but can be stimulated by a soluble factor (MCF) released in vitro from cultured human blood monocyte-macrophages. Monocyte cultures exposed to aggregated immunoglobulin, Fc fragments of immunoglobulin or concanavalin A (Con A) increase production of MCF several-fold more than the control cultures. MCF production by monocytes exposed to Fab fragments does not differ from controls. Although aggregated immunoglobulin, Fc fragments, and Con A stimulate PGE2 synthesis and secretion by human monocytes, the effects on MCF production are not mediated by PGE2 since concentrations of indomethacin that completely block PGE2 production do not inhibit MCF production. These findings of increased production of MCF by monocytes in response to substances that probably exert their effects via surface receptors could be relevant in interpreting the in vivo role of immune complexes in diseases associated with connective tissue destruction.

To examine directly the interaction of circulating proteins (CP) with the glycocalyx of pulmonary endothelium and its effect on endothelial permeability, two types of experiments were carried out. In the first, rats were exchange transfused with graded amounts of FC-43 fluorocarbon emulsion (FCE) resulting in CP concentrations of 25, 10, and 4 mg/ml, respectively. In the second, rats were exchange transfused with FCE to remove 99.9% of CP. The rats were then exchange transfused with 1 ml FCE containing 60 mg/ml of rat serum protein and killed 3.5, 7.5, and 15 min after the administration of protein. In all animals the distribution of albumin and immunoglobulin G (IgG) was visualized by immunocytochemistry, and endothelial permeability to native ferritin was measured by morphometry. In the depletion experiments increased endothelial permeability to ferritin coincided with loss of adsorbed albumin and IgG from the glycocalyx. Conversely, the presence of administered serum proteins in the glycocalyx and in a few luminal vesicles was associated with an endothelial permeability to ferritin indistinguishable from that of controls. These observations suggest that the adsorption of CP to the endothelial glycocalyx renders the underlying endothelium less permeable to ferritin.

To examine the effect of circulating proteins on the passage of intravenously injected native ferritin across pulmonary capillary endothelium, rats were exchange transfused with FC-43 fluorocarbon emulsion (FCE) under ether anesthesia. Protein concentration was reduced to less than 1.1 mg/ml by exchange transfusion, followed by FCE containing 15, 30, or 60 mg/ml of lyophilized rat serum protein (LRSP). Two minutes after ferritin injection lungs were prepared for ultrastructural morphometry. The diameter and numerical density of vesicles remained unchanged under all experimental conditions; however, at 0.6 mg/ml of circulating protein there was a 5- and 10-fold increase, respectively in percent vesicle (%VL) and basement membrane labeling (BML) by ferritin. This was reversible; at 60 mg/ml of circulating protein %VL and BML was indistinguishable from controls. Following a reduction of circulating protein to less than 1.1 mg/ml, the addition of 15 mg/ml LRSP reduced %VL but had no effect on BML. This suggests that in addition to shuttling vesicles there may be a second mechanism for the transport of ferritin, possibly involving transendothelial chains of vesicles.

The integrity of epithelial tight junctions in foetal mammalian lungs is essential to maintain the unique ionic composition of lung liquid, and to prevent leakage of serum proteins into peripheral air spaces. In the present study the development of intercellular junctions of the lining epithelium of foetal lamb lungs during gestation was examined by light and electron microscopy. Both thin sections and freeze-fracture replicas were examined by electron microscopy. By 39 days of gestation, epithelial tight junctions consist of a minimum of 3·1 ± 1·6 (S.D.) and a maximum of 5·8 ± 2·0 discontinuous rows of particles and short segments of strands on P face ridges and in complementary E face grooves, while from 58 to 76 days they are composed of a network of 4·3 ± 1·6 to 7·7 ±1·9 focally interrupted P face strands. Complementary replicas show that many of the discontinuities on the P face are due to separation of junctional particles on to the E face during fracturing, and not to an absence of junctional particles. From 76 days to term, epithelial tight junctions (exclusive of upper airway epithelium which was not examined) resemble those of adult lungs, and consist of a continuous network of 4·5 ± 2·0 to 7·5 ± 2·5 P face strands and complementary particle-free grooves. Permeability measurements, published elsewhere, indicate that the epithelium is functionally ‘tight’ from 69 days onwards. Tight junctions in peripheral air-space epithelium, therefore, are structurally continuous and functionally ‘tight’ early in foetal lung development, and form seals at one end of long, narrow intercellular spaces; these features may be important for coupled ion and water transport. When the bounding epithelial cells become flattened, these narrow intercellular spaces remain intact as a result of complex interdigitations of adjacent cell membranes. Desmosomes were present throughout gestation near the abluminal side of the tight junctions and occasionally near the base of the intercellular space. These junctions may serve to connect cells to each other at a time when tight junctions may be mechanically weak. In addition, gap junctions are associated with tight junctions from the glandular through the canalicular stages of lung development. They disappear by 120 days when the epithelial cells are differentiated.

The purpose of this study was to examine by freeze-fracture the ultrastructure of intercellular junctions between mouse pulmonary endothelial and epithelial cells, and to relate this fine structure to that deduced from previous physiological and ultrastructural studies using tracer techniques. Junctions between capillary endothelial cells consist of one to three interconnected rows of particles which show occasional discontinuities. Small gap junctions are associated with these rows of particles in the arteriolar end of the capillary bed. At the venular end, the junctions consist of low profile ridges on the protoplasmic fracture (PF) face or complimentary grooves on the exoplasmic fracture (EF) face some of which have a sparse number of associated particles. The vascular junctions are similar to those of vessels in rat omentum and mesentery, and resemble "leaky" junctions described in renal proximal convoluted tubular cells. Tight junctions (zonulae occludentes) between type I pneumocytes or between types I and II pneumocytes consist of a band of interconnecting ridges on the PF face and complimentary interconnecting grooves on the EF face. These continuous epithelial junctions have a structure that is typical of tight occluding junctions. Occasionally zonulae occludentes between type I and type II pneumocytes are discontinuous; this may be the result of cell translocation as pneumocytes are shed into the alveolus. Intravascular perfusion fixation at high pressure (140 cm H2O) had no discernible effect on the structure of endothelial or epithelial junctions. The appearance in our study of freeze-fractured pulmonary endothelial and epithelial junctions reveals clearly the physical basis for the results of ultrastructural tracer and physiological studies which have suggested that it is the alveolar epithelium rather than the endothelium that is the chief permeability barrier to small, water-soluble molecules.

The fluorocarbon exchange transfused rat was used to examine the effect of varying concentrations of circulating proteins on the permeability of pulmonary endothelium to inject ferritin. There is a significant inverse relationship between protein concentration and the relative number of vesicles containing ferritin as well as the amount of ferritin in the basement membrane. A hysteresis effect of the amount of circulating protein on the permeability of endothelium to ferritin was noted. In repletion experiments almost 2.5 times more protein was required to maintain capillary permeability at normal levels than during depletion experiments.

Plasma proteins interact with vascular endothelium in such a way as to render it less permeable to other macromolecules. Evidence from a variety of sources indicates that this may result from interaction of the circulating macromolecules with the negatively charged glycoprotein layer on the surface of endothelial cells, and that this layer may be responsible for some of the known molecular sieving properties attributed to the endothelium. Experiments with the fluorocarbon exchange-transfused rat are described, which suggest that there may be mechanisms other than vesicular translocation that facilitate the passage of macromolecules across endothelium. Such mechanisms include, among others, the formation of transient transendothelial channels that appear to be less sensitive than pinocytotic vesicles to the concentration of ambient protein. Recent evidence suggests that, in addition to molecular size and charge, glycosylation of protein molecules and cell membranes themselves may facilitate vesicular uptake.

A variety of benzamidine and pyridinium compounds were examined for their ability to inhibit irreversibly C1s-induced vascular leakage in guinea pig skin. Vascular leakage was compared with esterolysis of N-Z-L-Tyr-Np and catalysis of EAC42 formation by C1s. Vascular leakage correlated significantly better with esterolytic activity than with EAC42 formation. The presence of a sulfonyl fluoride moiety in the compounds is important in the inhibition of C1s-induced vascular leakage.

A distinctive glomerular lesion of renal allografts, acute allograft glomerulopathy (AAG), is characterized by hypercellularity and endothelial cell hypertrophy and injury. For elucidating the pathogenesis of this lesion, the infiltrating cells were analyzed by light- and electron-microscopic immunoperoxidase techniques with monoclonal antibodies and compared with those in cellular rejection without AAG (non-AAG). Substantial numbers of T lymphocytes (CD3+,Leu-4+) were detected in the glomeruli in AAG (11.4 +/- 2.4 cells per glomerular cross-section), whereas very few were found in non-AAG (1.4 +/- 1.8, P less than 0.001). In AAG the CD8+ (Leu-2a) subset accounted for essentially all of the intraglomerular T cells, which had a lower CD4/CD8 ratio than the corresponding peripheral blood lymphocytes (P less than 0.03). AAG also differed from non-AAG by the accumulation of intraglomerular mononuclear cells that expressed HNK-1 antigen (Leu-7) and mononuclear phagocytes, which were identified by the presence of the monocyte fibronectin receptor (A6F10). Intraglomerular mononuclear cells were positive for the interleukin-2 receptor (IL2R) and HLA Class II antigens (HLA-DR). The glomeruli in AAG stained more intensely for HLA Class I antigens than the tubules, in contrast to non-AAG cases (P less than 0.03). The interstitial infiltrates in AAG grafts were less intense than in non-AAG of similar duration (P less than 0.01) and had a lower CD4/CD8 ratio, whereas arterial intimal infiltrates were more severe in AAG (P less than 0.03) and consisted of CD8+, but not CD4+, cells. Pathologic features that correlated with poor graft survival were increased numbers of intraglomerular CD8+ cells (both AAG and non-AAG), fewer interstitial T cells (AAG), and more interstitial CD8+ cells (non-AAG) (all P less than 0.05). Cytomegalovirus (CMV) infection was detected in all (8/8) patients with AAG who were studied for infection before or within 3 weeks after the biopsy, compared with 3 of 9 patients with non-AAG. It is proposed that acute allograft glomerulopathy is a distinct form of T-cell-mediated allograft rejection, sometimes associated with CMV infection, in which the glomerular endothelium, often with the arterial endothelium, becomes the principal target of CD8+ T cells.

Two patients with a persistent mesangial proliferative glomerulonephritis and reduced serum C3 levels have been followed for six and 10 years. Both have had a mild course with normal renal function and spontaneous morphologic improvement. Levels of the fourth component (C4) and second component (C2) of complement, and properdin factor B have been normal; the third component (C3) of complement nephritic factor has not been detected. Ultrastructurally, irregular intramembranous electron-dense deposits are present, primarily within the lamina densa. These deposits are separated by varying lengths of normal-appearing glomerular basement membrane. Intramembranous and subendothelial electron-lucent areas, containing vesicles, are also seen. Subendothelial deposits, mesangial interposition, splitting of the glomerular basement membrane and ribbon-like intramembranous deposits are not found. The disease in these patients was clinically indistinguishable at onset from mrmbranoproliferative glomerulonephritis (MPGN). The possibility of a variant with mild clinical course, no progression and spontaneous morphologic improvement is important in planning and assessing treatment programs in this disease group.

A review of the histologic findings in 27 patients originally classified as having some form of membranoproliferative glomerulonephritis (MPGN) revealed 13 with MPGN Type I and 14 with dense deposit disease (DDD). In all 14 cases where electron microscopy was performed, the histologic diagnosis was confirmed. In nine cases the diagnosis of DDD was easily made in histologic sections on the basis of ribbon-like, brightly PAS positive thickening of the GBM, without "splitting" and with relatively slight mesangial proliferation. However, in five cases the picture closely resembled MPGN Type I, with hypercellularity, "splitting" and only focal ribbon-like thickening of the GBM, which required oil immersion for recognition. There was no correlation between the serum C3 levels and the morphologic diagnosis: nine (4 MPGN Type I, 5DDD) had persistently low C3 levels, two (1 MPGN Tye I, 1DDD) were normocomplementemic, and in 16, the C3 levels varied. C3 levels increased with time in nearly all patients. The clinical course was similar in patients with MPGN Type I and DDD. Significant correlations between the rate of development of renal failure and sex, age of onset, nephrotic syndrome or therapy could not be made. The five year survival rate was 87%; 12 developed renal insufficiency by five years. Although morphologically distinct, these findings suggest that DDD is clinically indistinguishable from MPGN Type I.

A patient with biopsy documented acute poststreptococcal glomerulonephritis and arteritis recovered completely with supportive therapy. Illness was preceded by group A streptococcal pharyngitis. At the time of presentation, serum creatinine concentration was 11.5 mg/dl. Serum cryoglobulins containing IgG and C3 were present. The first biopsy, performed during the acute illness, contained glomeruli with typical features of acute PSGN. Medium-sized arteries had extensive necrosis and leukocytic infiltration, and contained IgG, C3, and fibrin. Glomerular filtration rate returned to normal within three weeks; proteinuria cleared by three months, and microscopic hematuria by 11 months. Renal biopsy one year later showed minimal mesangial hypercellularity and no arteritis.

Cellular expression and extracellular deposition of fibronectin and fibrin/fibrinogen in experimental allergic encephalomyelitis (EAE) in guinea pigs (GP) were studied by light and electron microscopic immunohistochemistry of the central nervous system (CNS). Normal GPs had few fibronectin+ and fibrin/fibrinogen+ CNS vessels. Positively stained vessels were more numberous in sensitized GPs prior to and after onset of EAE, and there were extracellular deposits of these molecules in inflammatory foci. Staining was greater in EAE-susceptible strain 13 GPs than in sensitized EAE-resistant strain 2 GP. On ultrastructural analysis both molecules were localized on endothelial cell luminal surfaces and on intravascular mononuclear cells. Fibronectin and the macrophage fibronectin receptor (A6F10) were found on mononuclear cells in parenchyma. Endothelial cell luminal surface fibronectin and fibrin/fibrinogen may mark and/or contribute to early immune events in EAE, including mononuclear cell margination and emigration in inflammatory sites. Genetic factors, cytokines, and components of coagulation may regulate these interactions in vivo.

Neonates have an increased susceptibility to infections. Because optimal phagocytosis of offending organisms by alveolar macrophages (AM) requires recognition and attachment of opsonized organisms to the AM cell membrane, the expression of opsonic receptors on the surface of newborn and adult rat AM was investigated using immunologic techniques, cell culture, and flow cytometry. We investigated the expression of Fc, C3b, fibronectin, and lectin receptors on newborn (1 to 5 wk) AM and compared them with those of adult AM. The expression of Fc receptors (FcR) was significantly less on the surface of newborn AM, particularly during the first week of life, as determined by their binding of aggregated IgG, E(IgG), and opsonized 125I-Listeria monocytogenes. A similar depressed receptor function was observed for C3b, fibronectin, and some lectins. The possible effect of cell size on receptor expression was examined by morphometry and flow cytometry. The results indicated that, while mean AM size was approximately 12% smaller during the first week of life, it attained adult levels by the second week. Thus, a difference in size did not account for either the magnitude of decreased receptor expression or the diminished intensity of staining for surface-aggregated IgG that was detectable for up to 5 wk. Binding of a variety of lectins to the AM surface was decreased during the first week after birth, but approximated adult levels by 4 wk. By contrast, soybean and peanut agglutinin, lectins that bind to D-GaINAC moieties, showed a transient increase in binding to AM during the second and third weeks of life.(ABSTRACT TRUNCATED AT 250 WORDS)

Morphologic alterations of the slit diaphram and glomercular epithelium were examined in rats with experimental autologous immune complex nephritis following perfusion fixation with tannic acid-glutaraldehyde. The changes observed included a displacemnt by immune complex deposits of foot processes and associated slit diaphragms towards the urinary space. With the onset of proteinuria, foot processes spreas, resulting in a decrease in spithelial cell surface area and a diminution in the length of interpithelial slits. Concomiantly, the redundant slit diaphragm became folded and pleated in the residual interpithelial spaces. No primary defect in the slit diaphragm was observed to account fo the severe proteinuria seen in this disease. Instead areas of detached epithelial cells and an occasional slit pore lacking a slit diaphragm may consitute sites for substantial protein loss in the urinary space in autologous immune complex nephritis.

The intravenous injection into mice of small volumes (less than 0.1 ml) of peroxidatic enzymes of molecular weight of 40 000 daltons or greater results in little if any penetration of these probe molecules into endothelial junctions. The injection of cytochrome c (12 000 daltons), on the other hand, results in the localization of this tracer in some but not all endothelial junctions. When horseradish peroxidase (EC 1.11.1.7) is injected in a large volume of saline (0.5 ml), reaction product is present in endothelial junctions and basement membrane, but is prevented from entering the alveolar space by zonulae occludentes between epithelial cells. These experiments indicate that although endothelial junctions, under physiological conditions, are largely impermeable to molecules the size of horseradish peroxidase, and presumably most serum proteins, they are labile and susceptible to stretching if intravascular pressure is increased. Freeze-fracture studies show that pulmonary capillary endothelial junctions are composed of one or at the most two strands which show areas of discontinuity. Epithelial junctions, by contrast, are composed of a continuous, complex network of anastomosing fibres. These observations confirm physiological experiments which indicate that it is the pulmonary epithelium rather than the endothelium which determines the permeability properties of the alveolar-capillary membrane to lipid-insoluble molecules. Bidirectional pinocytic transport is an additional mechanism whereby lipid-insoluble molecules are transported across both endothelial and epithelial layers. The relative contribution of this transport mechanism to the total amount transported remains to be established.

The structural basis for the permeability of the alveolar-capillary membrane to water-soluble solutes rests in part on the structure and function of its intercellular junctions and the pinocytotic vesicles within its cells. Intercellular junctions between endothelial cells of the pulmonary capillary bed differ both in permeability to enzyme tracers and in their structure. As determined by freeze fracture, the junctions in the arteriolar, capillary, and venular portion of the capillary network vary in complexity, and in the number of rows of particles constituting the junction. Because there are few particles associated with the junctions in the venular end of the capillary bed, these are considered to be the most permeable of the three types of vascular junctions. Epithelial junctions, in contrast, are impermeable to all enzyme tracers studied, and they are composed of a continuous, complex network of junctional fibrils. While intercellular junctions form seals of varying 'tightness,' pinocytotic vesicles provide a means for the transport of water-soluble macromolecules across the alveolar-capillary membrane.

In the present study in Munich-Wistar rats during the initial stages of autologous immune complex nephritis (protein excretion 3 to 50 mg/24 hours) we examined the sequential changes in binding of cationized ferritin to anionic sites, as well as alterations in staining with colloidal iron of podocyte membrane sialoglycoprotein and correlated these with changes in glomerular basement membrane permeability to native ferritin. The results are compared with those obtained from rats with advanced autologous immune complex nephritis (protein excretion 100 to 350 mg/24 hours) and with normal control rats. The formation of the smallest detectable immune complex deposits was associated with a concomitant decrease in binding of cationized ferritin to anionic sites in the lamina rara externa in the area of the deposits. This was accompanied by a diminution in staining by colloidal iron of the epithelial cell coat overlying the deposits. The staining of the remainder of the epithelial cell glycocalyx, however, remained unaltered even in the presence of severe proteinuria. Alterations in the permeability of the glomerular basement membrane to native ferritin could not be documented until protein excretion exceeded 10 mg/24 hours. The gradual loss of staining of the epithelial cell glycocalyx adjacent to immune complexes supports the concept that, as immune complexes are formed in situ by the interaction of antibodies with a glycoprotein present on the epithelial cell surface, they are shed and gradually accumulate in the lamina rara externa. Furthermore, as the immune complex deposits enlarge they destroy and/or mask the heparan sulfate anionic sites in the lamina rara externa resulting in a decreased number of anionic binding sites for cationized ferritin.

A method has been developed for preparation of confluent monolayers of human monocytes from small volumes of blood and for maintenance of these pure monocyte cultures for up to 16 wk in vitro. These cells phagocytosed 5.7 mum diameter latex beads, rosetted with erythrocytes coated with IgG or with C3, killed Listeria monocytogenes, and synthesized both lysozyme and the second component of complement. Lysozyme was secreted at a rate of approximately 50,000 mol/min per cell for at least 12 wk in cultures. The maximal rate of C2 synthesis and secretion was considerably less; i.e., approximately 30 mol/min per cell between the 2nd and 12th wk in culture. Monocytes produced little C2 during the first 6 days in culture after which a marked increase in the rate of C2 production was noted. This increase was coincident with morphologic evidence of monocyte maturation.

The authors have prepared and studied three murine monoclonal antibodies that are reactive with antigens in brush border regions of proximal renal tubules of rats. Two of the antibodies, 14C1 and AG3, were derived from mice immunized with Fx1A and the third, 4H6, from a mouse immunized with isolated glomeruli obtained from rats with Heymann nephritis. Immunohistochemical, immunoelectron microscopic, and immunochemical studies showed that the three antibodies recognized different antigens. The antibody 14C1 recognized the previously described nephritogenic glycoprotein, gp 330, in microvillar brush border preparations, and reacted with material present on podocyte cell surfaces of normal rat kidneys, especially in coated pits, as well as with material in the glomerular deposits of rats with Heymann nephritis. The antibody 4H6 recognized a 110-kilodalton microvillar antigen and reacted with material in the glycocalyx of podocytes of normal glomeruli, but showed only equivocal reactivity with material in the deposits in Heymann nephritis. AG3 failed to immunoprecipitate a distinctive antigen in microvillar preparations and did not react with the glomeruli of normal rats or of rats with Heymann nephritis. All three antibodies reacted with epithelial cells in the intestine, epididymis, and placenta; 4H6 also reacted with thin loops of Henle as well as with endothelial cells or other cells in lung, lymphoid tissue, liver, and spleen. The results demonstrate that not all brush border antigens participate in Heymann nephritis and confirm that an antigen (gp 330) involved in the formation of glomerular deposits in Heymann nephritis is normally present on podocyte surfaces, especially in coated pits, but is not present in extracellular sites.

The altered functional properties of the glomerular capillary wall in a model of autologous immune complex disease (Heymann's nephritis) was studied by electron microscopy using intravenously injected protein tracers of varying molecular weight. There was an increase in the permeability of the glomerular basement membrane (GBM) itself to large molecules; this change was focal and was found in those areas where the GBM contained immune complex deposits. Both ferritin and catalase, tracers normally restricted from passing the glomerular filter, were present in the urinary space within minutes of injection. No evidence was obtained for increased glomerular epithelial transport in this disease. Foot process swelling and "close" junction formation was moderate, even in animals with marked degrees of proteinuria. Indirect evidence, therefore, makes an alteration in the slit pore complex likely. In addition, there was immediate and selective concentration of all tracers within deposits, though ferritin was partially excluded from some deposits. This phenomenon may be of significance in the perpetuation of the disease.