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Pre-existing HLA antibodies are a well-established causal factor for rejection and graft dysfunction after solid-organ transplantation. In lung transplant recipients, the significance of HLA antibodies has not been fully established. Although rare, several cases of hyperacute rejection of the lung allograft due to pre-existing donor-specific HLA antibodies have been described. In contrast, we describe successful lung transplantation in a patient with pre-existing donor-specific HLA antibodies. Routine screening prior to lung transplantation revealed cytotoxic HLA Class II antibodies, directed against the alpha chain of HLA-DQ, induced by a previous liver transplant. Due to clinical deterioration, it was decided to accept a lung offer without virtual crossmatching for DQ compatibility. Cytotoxic antibodies against the lung donor were confirmed retrospectively, resulting in strong positive B-cell crossmatches. Interestingly, the patient showed no clinical or histologic signs of rejection. This case demonstrates that the presence of high levels of pre-existing donor-specific HLA antibodies does not necessarily lead to rejection and graft failure. Although screening for antibodies prior to transplantation remains crucial, this study shows that we are thus far not able to predict the effect of pre-existing HLA Class II antibodies on allograft survival in individual patients., (Copyright © 2012 International Society for Heart and Lung Transplantation. Published by Elsevier Inc. All rights reserved.)

Background: In patients with end stage renal disease (ESRD) we observed protection from inflammation-associated mortality in CCR5Δ32 carriers, leading to CCR5 deficiency, suggesting impact of CCR5Δ32 on inflammatory processes. Animal studies have shown that CCR5 deficiency is associated with a more pronounced Th2 type immune response, suggesting that in human CCR5Δ32 carriers the immune response may be more Th2 type directed. So, in the present study we determined the Th1-Th2 type directed immune response in ESRD patients carrying and not carrying the CCR5Δ32 genetic variant after stimulation., Methodology/principal Findings: We tested this hypothesis by determining the levels of IFN-γ and IL-4 and the distribution of Th1, Th2 and Th17 directed circulating CD4+ and CD8+ T cells and regulatory T cells (Tregs) after stimulation in ESRD patients with (n = 10) and without (n = 9) the CCR5Δ32 genotype. The extracellular levels of IFN-γ and IL-4 did not differ between CCR5Δ32 carriers and non carriers. However, based on their intracellular cytokine profile the percentages IL-4 secreting CD4+ and CD8+ T cells carrying the CCR5Δ32 genotype were significantly increased (p = 0.02, respectively p = 0.02) compared to non carriers, indicating a more Th2 type directed response. Based on their intracellular cytokine profile the percentages IFN-γ and IL-17 secreting T cells did not differ between carriers and non-carriers nor did the percentage Tregs, indicating that the Th1, Th17 and T regulatory response was not affected by the CCR5Δ32 genotype., Conclusions/significance: This first, functional human study shows a more pronounced Th2 type immune response in CCR5Δ32 carriers compared to non carriers. These differences may be involved in the previously observed protection from inflammation-associated mortality in ESRD patients carrying CCR5Δ32.

Background: Cytomegalovirus (CMV) is a risk factor for rejection and mortality soon after renal transplantation. Little is known about its consequences longer after transplantation. We prospectively investigated whether latent CMV infection is a risk factor for graft failure and mortality long after transplantation., Material/methods: Our study included 606 renal transplant recipients (RTR) with a functioning graft for >1 year. CMV serology was determined using ELISA. RTRs were divided into CMV-seronegative and latent CMV (seropositive + seroconverted)., Results: We measured CMV IgG at 6.0 [2.6-11.4] years post-transplant. During follow-up (7.0 [6.2-7.5] years), 54 (9%) RTRs experienced graft failure and 137 (23%) RTRs died. Risk for graft failure and mortality was significantly higher in RTRs with latent CMV compared to CMV-seronegative RTRs (HR=3.1, P=0.005 and HR=2.0, P=0.002, respectively). After adjustment for potential confounders, latent CMV infection remained an independent risk factor for graft failure (HR=4.6, P=0.001), but not for mortality (HR=1.4, P=0.2)., Conclusions: Latent CMV is an independent risk factor for graft failure long after renal transplantation and carries a higher risk for graft failure than for mortality. These findings confirm the notion that latent CMV can be harmful in transplanted kidneys.

Female kidneys and kidneys from small donors have been suggested to perform worse after kidney transplantation. Here, we evaluate the impact of gender and body dimensions on posttransplantation GFR in living donor transplantation. Two hundred and ninety-three donor-recipient pairs, who were transplanted at our center were evaluated. All pairs had detailed renal function measurement ((125) I-iothalamate and (131) I-hippuran) 4 months predonation in the donor and 2.5 months posttransplantation in donor and recipient. For 88 pairs, 5 years of recipient follow-up was available. Delta GFR was calculated as (recipient GFR-donor single kidney GFR). Recipients of both male and female kidneys had similar renal function at early and long term after transplantation. Male recipients had higher ERPF, ΔGFR and ΔERPF at both time points. Kidneys of donors smaller than their recipient had higher ΔGFR and ΔERPF than kidneys of larger donors at both time points (p < 0.05). In multivariate analysis, ΔGFR was predicted by donor/recipient BSA-ratio together with transplantation related factors (R(2) 0.19), irrespective of donor and recipient gender. In conclusion, in living donor transplantation, female kidneys perform as well as male donor kidneys. Kidneys adapt to the recipient's body size and demands, independent of gender, without detrimental effects in renal function and outcome up to mid-long term., (©2011 The Authors Journal compilation©2011 The American Society of Transplantation and the American Society of Transplant Surgeons.)

Chronic low-grade inflammation is involved in late renal transplant dysfunction. Recent studies suggest a role for hemopexin, an acute phase protein, in kidney damage. We investigated whether hemopexin activity (Hx) predicts graft failure in renal transplant recipients (RTRs). In 557 RTRs with functioning grafts for >or=1 year, Hx was measured in citrate-plasma. RTRs were divided according to Hx into two groups; A: sextile 1-5 (464 RTRs, 83%) and B: sextile 6 (92 RTRs, 17%). Hx [median (IQR) 11.1 (3.3-19.1) arbitrary units] was measured at 6.0 (2.6-11.5) years post-transplant. RTRs with high Hx (group B) had significantly higher urinary protein excretion (UP) and diastolic blood pressure than group A, despite significantly more prevalent use of renin-angiotensin-aldosterone system inhibitors. After follow-up [4.6 (3.8-5.2) years], incidence of graft failure in group A was 25 (5%) and in group B 14 (15%,P = 0.0009) After adjustment for high-sensitivity C-reactive protein (hsCRP), UP and other potential confounders, Hx remained an independent predictor of graft failure [HR = 2.5 (95% CI 1.2-5.3), P = 0.01]. In conclusion, elevated Hx predicts late graft failure in RTRs, independent of hsCRP and UP. This suggests that Hx measurement, next to measurement of creatinine clearance and UP, could be of value for the identification of RTRs at risk for graft failure.

Background: Chronically elevated vasopressin (VP) plasma levels have been shown to induce accelerated renal function decline in rats with chronic renal failure. Whether endogenous VP is a renal risk factor in humans has not been investigated yet. We aimed to investigate whether, in renal transplant recipients, VP concentration is associated with change in renal function during follow-up., Methods: In this prospective study, all consecutive patients visiting our kidney transplant outpatient clinic between August 2001 and July 2003 were asked to participate. Serum creatinine was assessed at baseline and at follow-up. Copeptin, the C-terminal portion of the precursor of VP, was determined at baseline (immunoassay). Univariate and multivariate regression analyses were performed to investigate the association between copeptin and renal function decline., Results: Overall, 548 patients were included 6.0 (2.8-11.6) years after transplantation (men 54%, age 52 [43-60] years). Median follow-up was 3.2 (2.7-3.7) years. Median copeptin level was 9.1 (5.0-18.6) pmol/L at baseline. Copeptin was significantly associated with change in estimated Glomerular Filtration Rate (eGFR; MDRD) during follow-up. When our study population was subdivided according to gender-stratified tertiles of increasing copeptin concentration, mean changes in eGFR during follow-up were -0.03, -0.44, and -1.06 mL/min/1.73 m2 per year. In multivariate regression analysis, the association of copeptin at baseline with change in eGFR during follow-up remained significant after adjustment for age, gender, baseline eGFR, and known risk factors for renal function decline., Conclusions: These findings suggest that in renal transplant patients, VP may play a role in renal function decline.

Background: Female renal transplant candidates are prone to be sensitized by prior pregnancies, and undetected historical sensitization might decrease transplantation outcome. Hypothesis of our study was that pre-transplant blood transfusions (PTFs) can elucidate historical sensitization and that the avoidance of the associated antigens can improve transplantation outcome., Methods: Data from all female non-immunized renal transplant candidates who received a random PTF (rPTF) (n = 620), matched PTF (mPTF) (one HLA-A and B and one HLA-DR match) (n = 86) or donor-specific blood transfusion (DST) (n = 100) between 1996 and 2006 were collected. Complement-dependent cytoxicity was used to detect anti-HLA antibodies. Sensitization and transplantation outcomes after a PTF were analyzed. Non-immunized female renal transplant recipients who did not receive a PTF were used as the control group., Results: In 165 patients, anti-HLA antibodies (IgG) were detected after the PTF. Both historical and primary sensitizations were found. A DST induced donor-specific anti-HLA antibodies in 25% of the DST recipients. Our policy did not improve transplantation outcome in recipients of a kidney from a deceased donor (n = 368) or in recipients of a living donor [DST (n = 49) and mPTF (n = 66)]., Conclusions: A PTF did elucidate historical sensitization but induce primary sensitization as well. No beneficial effect of PTFs on transplantation outcome was found, and PTFs with the intention to detect historical sensitization are therefore not suggested.

Objectives: As the HLA system is involved in recognition of self and non-self, an association with the development of ANCA-associated vasculitis (AAV) seems probable. In this study, the relation between HLA antigens and AAV and it's severity were investigated., Methods: Consecutive patients diagnosed with AAV at our centre, who were followed for at least 2 years, were included. The frequency of HLA antigens of AAV and WG patients was compared with 5872 healthy blood donors from the same region and with 4000 healthy Dutch controls originating from a Eurotransplant database., Results: From 304 AAV patients, sufficient data were available. We found DR13(6) to be less prevalent and both DR4 and the ancestral haplotype A1B8DR3 more prevalent in patients with AAV compared with controls, particularly in patients with WG. In addition, DR1 was less prevalent in patients with WG in comparison with controls. Further, DR8 was more prevalent in patients with CSS compared with other forms of vasculitis and controls. There were no associations between HLA antigens and disease characteristics or course of AAV or WG., Conclusions: AAV is associated with increased prevalence of DR4 and the ancestral haplotype A1B8DR3 and with decreased prevalence of DR13(6), particularly in patients with WG. In patients with WG, prevalence of DR1 was decreased, whereas in patients with CSS DR8 was increased. No associations between HLA antigens and disease characteristics or course of AAV were found.

The aim of this study was to analyze the effect of human leukocyte antigen (HLA) class I and HLA-DR mismatching, sharing cross-reactive antigen groups (CREGs), and sharing HLA-DR antigens on the outcome after pediatric liver transplantation. Outcome parameters were graft survival, acute rejection, and portal fibrosis. A distinction was made between full-size (FSLTx) and technical-variant liver transplantation (TVLTx). A total of 136 primary transplants were analyzed. The effect of HLA on the outcome parameters was analyzed by adjusted multivariate logistic and Cox regression analysis. HLA mismatches, shared CREGs, and shared HLA-DR antigens affected neither overall graft survival nor survival after FSLTx. Survival after TVLTx was superior in case of 2 mismatches at the HLA-DR locus compared to 0 or 1 mismatch (P = 0.01) and in case of no shared HLA-DR antigen compared to 1 shared HLA-DR antigen (P = 0.004). The incidence of acute rejection was not influenced by HLA. The incidence of portal fibrosis could be analyzed in 62 1-yr biopsies and was higher after TVLTx than FSLTx (P = 0.04). The incidence of portal fibrosis after TVLTx with 0 or 1 mismatch at the HLA-DR locus was 100% compared to 43% with 2 mismatches (P = 0.004). After multivariate analysis, matching for HLA-DR and matching for TVLTx were independent risk factors for portal fibrosis. In conclusion, an overall beneficial effect of HLA matching, sharing CREGs, or sharing HLA-DR antigens was not observed. A negative effect was present for HLA-DR matching and sharing HLA-DR antigens on survival after TVLTx. HLA-DR matching might be associated with portal fibrosis in these grafts.

Although several risk factors for posttransplant lymphoproliferative disease (PTLD) after solid organ transplantation have been identified, the immunosuppressive regimen probably as most important one, their exact pathogenic role and relevance is still unclear. In hematopoietic stem cell transplantation, HLA mismatching also is a risk factor. We analyzed factors possibly associated with development of PTLD in patients receiving a kidney transplant at our hospital between 1985 and 2002. PTLD was observed in 20 out of 1,013 patients (2.0%). Mismatches at the HLA-B locus, but not at the HLA-A or HLA-DR loci, and anti T-cell antibody therapy were both independently associated with development of PTLD. Hazard ratios increased from 1.4 (0.5-4.1) with one mismatch to 5.1 (1.4-19.0) in case of two HLA-B mismatches. Decreased surveillance by T-cells with dual specificity for Epstein-Barr virus (EBV) as well as for allo HLA antigens on the allograft might facilitate clonal expansion of B-cells latently infected with EBV.

The characterization of three novel DRB1 alleles is described, DRB1*0107, DRB1*0425 and DRB1*13012 as well as confirmation of DRB4*01033. Two alleles, DRB1*0107 and *0425, showed amino acid differences with previously identified HLA molecules. In DRB1*0107, the glutamine at position 10 was substituted by a glutamic acid. DRB1*0425 showed one amino acid difference with DRB1*0418 (I to F) at position 67, and five amino acid differences with DRB1*04011 at positions 67 (L to F), 70 (Q to D), 71 (K to R), 74 (A to L) and 86 (G to V). The alleles DRB1*13012 and DRB4*01033 had protein sequences identical to DRB1*13011 and DRB4*01031/01032, respectively. Nucleotide differences were present at position 306 for DRB1*13012 and at position 321 for DRB4*01033.

In this report, the novel allele B*40351 is presented. The allele was identified in a Caucasian individual by sequence-based typing. B*4035 is identical to B*4002 in exon 2, but differs in exon 3 at position 463, where it has an A in stead of a C. This results in an amino acid change from arginine to serine at codon 131 of the mature protein. The haplotype carrying the B*4035 was A3 B*4035 Cw2 DR11 DQ3.

In this report we describe a novel HLA-A*34 allele, A*3404, which was initially detected by an unusual serological pattern in two unrelated individuals. Sequencing revealed that the new allele was identical to A*3402 in exons 2 and 3, except for a single nucleotide difference at position 238, changing codon 56 from glycine to arginine. The codon change resulted in positive serological reactions with several sera recognizing A30 and/or A31, implicating an important role for this position in epitope recognition. The allele was identified twice on the haplotype A*3404, B*1402, Cw*0802, DRB1*14, DQB1*05.

Background: This study is designed to examine a possible association of cardiopulmonary bypass (CPB) support and outcome of lung transplantation in a well-balanced group of emphysema patients., Methods: We performed a retrospective analysis of 62 consecutive primary bilateral lung transplantations for emphysema. Risk factors for their possible association with patient survival were analyzed by multivariate logistic regression., Results: The use of CPB support was associated with improved survival (odds ratio=0.25; P=0.038). The actuarial survival at 1 year was 97% for patients treated with CPB and 77% for patients treated without CPB support. In 28 patients (45%), 2 human leukocyte antigen (HLA)-DR mismatches between donor and recipient occurred, whereas 34 patients had 0 or 1 HLA-DR mismatches. The use of CPB support in the group with two HLA-DR mismatches was associated with improved survival (odds ratio=0.06; P=0.020). This association was not present in the group with 0 or 1 HLA-DR mismatches., Conclusions: These results demonstrate a significant survival benefit of CPB support during bilateral lung transplantation in emphysema patients. The difference in survival benefit of CPB support between the patients with 0 or 1 HLA-DR mismatches and the patients with 2 HLA-DR mismatches indicates that the immunosuppressive effect of CPB support might be responsible for this survival benefit. The underlying immunological mechanism might be important in the future treatment of organ transplantation.

In our recent study using high-resolution HLA-B locus typing by sequence-based typing (SBT) we identified 9 new alleles in a total of 355 unrelated individuals (4). Three of them concerned an allele belonging to the B22 group. One of them, B*5607, showed the unusual presence of a Bw4 sequence motif, as described previously (5). In this report the other two B22 variants are described; one belonging to the B55 specificity and named B*5509; the other one being a B*56 allele and assigned B*5606, which brings the total number of alleles belonging to the B22 group to 18.

Background: A decrease in donor-specific T cell precursor frequencies as seen late, one or more years, after transplantation is assumed to reflect transplantation tolerance, a condition important for long term acceptance of the allograft. However, such late decreases also occur in recipients that developed chronic transplant dysfunction questioning its relevance in transplantation tolerance. We investigated whether early, i.e., the first 6 months, decreases in donor-specific T cell precursor frequencies reflect transplantation tolerance and predict graft outcome after liver and lung transplantation., Methods: Donor and third party specific cytotoxic (CTLp) and helper T lymphocyte precursor (HTLp) frequencies were analyzed in pretransplant and 1 (or 2) and 6-month blood samples taken from liver and lung recipients and were correlated with graft outcome., Results: In liver allograft recipients with good graft function (n=7), mean donor-specific CTLp frequencies decreased as early as 1 month after transplantation and remained low thereafter. In contrast, mean CTLp frequencies did not decrease in liver allograft recipients with chronic transplant dysfunction (n=6). In lung allograft recipients, donor-specific CTLp frequencies remained relatively high and frequencies were not different between recipients without (n=6) or with (n=6) chronic transplant dysfunction. Donor-specific HTLp frequencies did not change significantly after liver or lung transplantation and did not differ between recipients without or with chronic transplant dysfunction., Conclusions: An early decrease in donor-specific CTLp correlates with good graft outcome after liver transplantation. Such rapid decreases in alloreactivity do not occur after lung transplantation illustrating the unique capacity of liver allografts to induce transplantation tolerance.

Background: The importance of HLA mismatch in determining long-term outcome in lung transplantation remains largely uncertain., Methods: A retrospective analysis of 102 consecutive primary lung transplants was performed to identify risk factors for poor long-term outcome after lung transplantation defined as graft survival and bronchiolitis obliterans syndrome (BOS) stage I and II. Variables included were patient characteristics (age, sex, prior diagnosis), the number of HLA mismatches between donor and recipient, cold ischemic time, cytomegalovirus serologic concordance, number of acute rejections, and time to first rejection. Variables carrying significance in a univariate analysis were subjected to a proportional hazard regression analysis., Results: In the multivariate analysis, an increased number of acute rejections correlated positively with decreased graft survival (risk ratio [RR] = 1.25; 95% confidence interval [CI], 1.05-1.5; P = 0.011), development of BOS stage I (RR = 1.36/episode; 95% CI, 1.16-1.58;P < 0.001), and BOS stage II (RR = 1.42/episode; 95% CI, 1.2-1.67; P < 0.001). An increased time to rejection correlated positively with reduced graft survival (RR = 1.03/day; 95% CI, 1.01-1.06; P = 0.02), and BOS stage I and II (both RR = 1.04/day; 95% CI, 1.01-1.07; P < 0.005). Compared with 2 HLA-DR mismatches, 0 or 1 mismatch was associated with improved graft survival (RR = 0.43; 95% CI, 0.19-0.98; P = 0.045) and protected against development of BOS stage I (RR = 0.47; 95% CI, 0.23-0.98; P = 0.044) and BOS stage II (RR = 0.35; 95% CI, 0.15-0.83; P = 0.017)., Conclusions: HLA-DR mismatching appears to be a risk factor for the development of BOS and graft loss. Improved outcome after lung transplantation might be achieved with prospective matching for HLA-DR. Alternatively, the amount and type of immunosuppressive drugs may be guided by the degree of HLA-DR (mis)matching.

Background: The development of immunological donor-specific hyporeactivity may account for the low incidence of chronic rejection after clinical liver transplantation. We investigated whether hyporeactivity commonly develops after liver transplantation by analyzing precursor frequencies of donor-reactive cytotoxic (CTLp) and helper (HTLp) T lymphocytes and mixed lymphocyte culture (MLC) reactivity in liver allograft recipients. We further studied whether CTLp hyporeactivity correlated with changes in donor-specific HTLp frequencies or suppressor cell activity., Methods: CTLp and HTLp frequencies and MLC reactivity against donor and third-party spleen cells were determined in pre- and posttransplantation peripheral blood samples from 18 recipients with good graft function 2 years after transplantation. By mixing posttransplantation samples (with "putative" suppressor cell activity) with pretransplantation samples (in which normal CTL activity with no suppressor cell activity is expected), the presence of suppressor cell activity in peripheral blood was analyzed., Results: Two years after transplantation, all but one (94%) of the recipients had developed CTLp hyporeactivity as evidenced by reduced donor-specific CTLp frequencies. The development of hyporeactivity was not specific for any particular underlying disease. The occurrence of HTL hyporeactivity, however, was less frequent: 38% and 20% of recipients were HTLp and MLC hyporeactive, respectively. Decreases in CTLp frequencies did not correlate with decreased donor-specific HTL function or suppressor cell activity in peripheral blood samples., Conclusions: Donor-specific CTLp hyporeactivity can develop in the majority of liver allograft recipients, irrespective of underlying disease. Donor-specific HTL hyporeactivity, however, occurs infrequently. A reduction in donor-specific CTLp frequencies was found to be independent of changes in donor-specific HTLp or suppressor cell activity, suggesting that other mechanisms (e.g., clonal deletion) are operative in the reduction of donor-specific CTLp after liver transplantation.

Background/aims: Gilbert's syndrome is genetically characterized by an extra TA element in the TATAA-box of the promotor region upstream of the bilirubin UDP-glucuronosyltransferase (UGT1A) coding region (Bosma et al. N Engl J Med 1995; 333: 1171-5). Persistent unconjugated hyperbilirubinemia is occasionally observed in liver transplant recipients with an otherwise normal liver function. We postulate that these patients could have received a liver from a donor with the Gilbert's syndrome genotype. Therefore, we investigated the UGT1A-gene TATAA-box in DNA from liver graft donors of jaundiced and non-jaundiced recipients., Methods: DNA was obtained from stored donor lymphocytes and the number of TA elements in the TATAA-box of the UGT1A-gene promotor region was analyzed by polymerase chain-reaction., Results: We observed two liver transplant recipients with persistent unconjugated hyperbilirubinemia. They received liver grafts from donors who were homozygous for an abnormal A(TA)7TAA-box in the UGT1A-gene. Four of 10 non-jaundiced recipients received livers from donors who were homozygous for the normal A(TA)6TAA-box and six received livers from donors who were heterozygous with a normal A(TA)6TAA-box on one allele and a prolonged A(TA)7TAA-box on the other allele., Conclusions: This study shows that liver graft recipients with persistent unconjugated hyperbilirubinemia may have received a liver from a donor with an abnormal TATAA-box in the bilirubin UGT1A-gene promotor region.

The aim of the present study was to analyze whether acquired transplantation tolerance had developed in patients with a long-term surviving renal or liver allograft. Analysis of antidonor cytotoxic T cell precursor frequencies was performed in 31 renal allograft recipients and 9 liver allograft recipients with good graft function 2 years after transplantation. The results demonstrated that, before transplantation, normal antidonor T cell responses were generated in both groups of patients. Two years after transplantation, donor-specific CTL nonresponsiveness had developed in a minority of the renal transplant recipients. In contrast, 8 out of 9 liver transplant recipients showed donor-specific mixed lymphocyte culture and CTL nonresponsiveness. These findings indicate that development of donor-specific T cell nonresponsiveness is not a common event after kidney transplantation, whereas liver transplantation seems to induce, at least in vitro, a state of donor-specific T cell nonresponsiveness.

Cytomegalovirus (CMV) infection and HLA-DR sharing have been reported to be associated with the development of vanishing bile duct syndrome (VBDS) after liver transplantation. We retrospectively analyzed the importance of these risk factors for VBDS in 126 consecutive recipients of a first transplant. In contrast to previous studies, CMV was monitored strictly using the antigenemia assay, a quantitative marker of the viral load. Patient and graft survival were comparable in patients with and without CMV infection. The incidence of VBDS was low, regardless of the CMV infection status or degree of HLA-DR sharing. Improvements in the early diagnosis and treatment of CMV infection may have eliminated its negative influence on graft survival.

The pathogenesis of Wegener's granulomatosis, microscopic polyangiitis and idiopathic rapidly progressive glomerulonephritis (RPGN) is still unclear; in vitro data support both humoral and cellular autoimmune mechanisms. An association of Wegener's granulomatosis with HLA antigens has been described, with conflicting results concerning the antigens involved. We have performed serological HLA typing of patients at two different laboratories within the Netherlands (N = 118 and N = 106,N respectively). A significant decrease in the frequency of HLA-DR13DR6 was present in both patient groups in comparison to controls (chi 2 = 21.9; corrected P value < 0.004 for both groups together). There were no differences in the distribution of HLA-antigens between patients with Wegener's granulomatosis and microscopic polyangiitis, between cANCA (cytoplasmic anti-neutrophil cytoplasmic antibodies) and pANCA (perinuclear ANCA, anti-MPO) positive patients, and between patients with and without relapsing disease.

The frequency of HLA types in a selected group of 40 patients with myasthenia gravis in relation to the effect of thymectomy and also to gender, and thymus histology was studied. As generally described we found a significant increase in the frequency of HLA-A1, HLA-B8, HLA-DR3 and HLA-DQ2 in the total group. There were no further differences between subgroups of patients, which demonstrates that HLA type is not indicative for the effect of thymectomy in myasthenia gravis.

Intravenous injection of methylated bovine serum albumin (mBSA) into mice with unilateral chronic mBSA-induced arthritis (AIA) causes a flare-up of the joint inflammation without affecting the contralateral non-arthritic knee joint. We studied the mechanism of the flare-up by decomplementation with cobra venom factor (CoVF) and by treatment with anti-lymphocyte serum (ALS) prior to the induction of the flare-up. Treatment of mice with CoVF had no effect on the induction of the flare-up reaction whereas a reversed passive Arthus reaction (RPA) in the ear of similarly treated mice was clearly suppressed. The complement activity in the serum was zero at 2 h after CoVF treatment and remained for 24 h. This indicates that this type of flare-up reaction is not complement-dependent. On the other hand, the flare-up reaction was completely abolished after treatment with ALS. Control experiments revealed that ALS treatment diminished the number of lymphocytes in the peripheral blood and clearly suppressed a delayed hypersensitivity reaction in the ear, but had no effect on an RPA. These results suggest an important role of T lymphocytes in the mechanism of the flare-up of arthritis. T lymphocytes were demonstrated in the synovial tissue of chronically inflamed joints by immunofluorescence and appeared to be diminished after ALS treatment. Interaction between exogenous antigen and antigen reactive T lymphocytes present in chronically inflamed joints, may be an important principle in the exacerbation and propagation of joint inflammation.

B6AF1 anti-B10.D2 ascites fluid was separated in highly purified IgG1 and IgG2 alloantibodies, which were concentrated to yield similar specific antibody activities on the basis of two-stage lymphocytotoxicity. Their similar specific activities were confirmed by flow cytometric analysis. When tested for enhancement of B10.D2 skin, grafted onto B6JAF1 recipients, and for the opsonization of 51Cr-labelled B10.D2 leukocytes, IgG1 antibodies were as effective as the IgG2 preparation. Therefore IgG1 and IgG2 antibodies have similar enhancing capacities. The close correlation with their opsonizing effect supports the hypothesis that interaction of the Fc-part of enhancing alloantibody with Fc-receptor bearing cells is involved in the induction of enhancement.

Three anti-H-2Ld and two anti-H-2Dd monoclonal alloantibodies were analyzed for their capacity to enhance skin graft and neonatal heart graft survival. Of two anti-H-2Ld antibodies with the same specificity but with different isotypes, IgG2a antibody 30-5-7S prolonged graft survival in a skin graft combination with an Ld difference, whereas IgM antibodies did not. A second IgG2a antibody, but with a specificity different from 30-5-7S, was ineffective on its own. However, when mixed with 30-5-7S, skin graft survival was augmented as compared with the prolongation by 30-5-7S alone. Enhancement by anti-H-2Ld antibodies was dependent on the extent of the H-2 graft barrier. It was abrogated on extension of the graft barrier to a D-end H-2 difference by using the B10.A----B10.BR combination. Also, anti-Dd antibodies, either alone or in combination with anti-Ld, were ineffective in this skin graft combination. By using the same graft combination but the less immunogenic neonatal heart graft model, anti-Ld antibodies were still ineffective, but both anti-Dd antibodies were able to enhance graft survival from 15 to 22 days. When mixed with anti-Ld antibody 30-5-7S, graft survival was augmented further to 30 days. These results indicate that two kinds of enhancing alloantibodies may be distinguished. One category interacts with immunodominant epitopes on H-2 molecules, but their effectiveness may be limited to a particular H-2 difference, because immunodominance may vary from one graft barrier to another. In the second category, antibodies are ineffective on their own but they are able to potentiate the effects of antibodies of the first kind. These allocations are relative, however, because they are dependent on the type of graft examined.

Monoclonal anti-H-2k alloantibodies were analyzed for their capacity to enhance the survival of B10.A skin grafted onto B10.D2 recipients. Included were five anti-class I and four anti-class II antibodies. In contrast to conventional B10.D2 anti-B10.A serum, none of the individual anti-class I or anti-class II monoclonal antibodies induced enhancement. The same negative results were obtained with various mixtures of anti-class I, anti-class II, or anti-class I + anti-class II antibodies. The failure to induce enhancement was not due to inefficient antigen binding in vivo, because monoclonal antibodies were as effective as conventional B10.D2 anti-B10.A serum in the induction of acute antibody-mediated graft rejection, and in the opsonization of 51Cr-labeled B10.A leukocytes injected into B10.D2 recipients pretreated with antibody. These results demonstrate that monoclonal antibodies cannot always substitute for conventional sera, at least not in immune regulation. They also show that although opsonization may be a prerequisite for the induction of enhancement, it does not guarantee that enhancement will invariably occur.

Transplantation antigens were isolated from murine tissue by solubilization with NP-40 and purification on a lentil lectin-Sepharose column. The glycoproteins eluted from the lectin column were coupled to CNBr-activated Sepharose to prepare a specific immunoadsorbent. Intact histocompatibility antigens were demonstrated on the carrier particles in a cytotoxic inhibition assay with specific antiserum and spleen lymphocytes. Adsorption and subsequent elution of alloantiserum directed against the coupled antigens yielded a 30-fold purified product. The presence of both active K and I region products on the column was demonstrated by the in vivo activities of the alloantibodies eluted from the coupled molecules. Both acute rejection, a function of H-2K antibodies, and passive enhancement, a function of Ia antibodies, could be induced by administration of the eluate to recipients of skin allografts. These in vivo results show that the adsorbent can be used for preparative purposes.