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The in vitro susceptibility of 38 strains of Francisella tularensis (biovar F. tularensis palaearctica) was determined using Etests on cysteine heart agar plates with 2% haemoglobin. All strains were susceptible to the antibiotics traditionally used to treat tularaemia, such as streptomycin (MIC(90) 4.0 mg/L), tetracycline (MIC(90) 0.38 mg/L) and chloramphenicol (MIC(90) 0.38 mg/L), and to aminoglycosides, such as tobramycin (MIC(90) 1.5 mg/L) and gentamicin (MIC(90) 1.0 mg/L). The quinolones examined had low MIC(90)s: ciprofloxacin, 0.016 mg/L; levofloxacin, 0.016 mg/L; grepafloxacin, 0.047 mg/L; and trovafloxacin, 0.032 mg/L. In contrast, all the strains were resistant to beta-lactams and azithromycin. Quinolones thus seem to be promising drugs for the treatment of tularaemia. [ABSTRACT FROM AUTHOR]

The aim of the study was to assess the prevalence of rheumatoid factor (RF) in a community-based rheumatoid arthritis (RA) series. The subjects of the series represented prevalent RA cases in the Kuusamo community in Northern Finland with 13,000 adult inhabitants. The patients were selected from the official Finnish data registers and from among the subjects who had consulted the local general practitioners due to rheumatic complaints in the recent years, using the American Rheumatism Association (ARA) 1987 classification criteria for inclusion. For this study, ninety-five out of the 103 RA patients so found were RF-tested by immunoturbidimetry. At the time of the study. 71 (75%) of the 95 cases were RF positive, 83 (87%) being 'ever' positive (in one case the early RF status was unclear). Our result contrasts with the much lower prevalence figures (25-60%) obtained from the earlier cross-sectional population-based RA studies, which have used the ARA 1958 definite RA as the inclusion criterion of the subjects. All the eleven patients with RF-negative RA had erosive joint disease. The RF-negative RA patients had a significantly lower frequency of HLA-DR4 (18%) than the RF-positive ones (58%), p < 0.05. We found a high frequency of RF among prevalent community-based RA cases meeting the ARA criteria. According to our results, RF-negative non-erosive RA is very rare among cases selected with the above methods. [ABSTRACT FROM AUTHOR]

Nickel is the major cause of metal-induced allergic dermatitis. Twelve nickel-specific T cell clones were used to investigate the cellular immune reactions occurring in nickel sensitivity. The selection between the alternative T cell receptors αβ and γδ and two alternative Vβ genes (Vβ5 and Vβ8) were studied to see if nickel induces a selective pressure for clones bearing particular genes. Cell surface markers were studied by monoclonal antibodies and flow cytometry. Soluble mediators were measured by an ELISA method. The clones used T cell receptor αβ genes but did not use Vβ5 or Vβ8. They were T helper clones with a primed memory marker (CD3+CD4+CD8-CD45RO+) and carried HLA-DR. None of the clones secreted IL-1α, all of them secreted IL-2 receptor. Four clones secreted IL-1β, six IL-4 and seven IL-6, the peaks in IL-2R and IL-6 secretion preceding IL-4 secretion. The clones helped immunoglobulin synthesis. The clones from late effector phase of the nickel allergic reaction favours the use of T cell receptors αβ genes. Nickel-specific clones were phenotypically indistinguishable but differed in soluble mediators produced. [ABSTRACT FROM AUTHOR]

Importance: Although topical antibiotics are often prescribed for treating acute infective conjunctivitis in children, their efficacy is uncertain., Objective: To assess the efficacy of topical antibiotic therapy for acute infective conjunctivitis., Design, Setting, and Participants: A randomized clinical trial was conducted in primary health care in Oulu, Finland, from October 15, 2014, to February 7, 2020. Children aged 6 months to 7 years with acute infective conjunctivitis were eligible for enrollment. The participants were followed up for 14 days. A subsequent meta-analysis included the present trial and 3 previous randomized clinical trials enrolling pediatric patients aged 1 month to 18 years with acute infective conjunctivitis., Interventions: Participants in the present randomized clinical trial were randomized to moxifloxacin eye drops, placebo eye drops, or no intervention., Main Outcomes and Measures: The primary outcome in the present randomized clinical trial was time to clinical cure (in days); in the meta-analysis, the primary outcome was the proportion of participants with conjunctival symptoms on days 3 to 6., Results: The randomized clinical trial included 88 participants (46 [52%] girls), of whom 30 were randomized to moxifloxacin eye drops (mean [SD] age, 2.8 [1.6] years), 27 to placebo eye drops (mean [SD], age 3.0 [1.3] years), and 31 to no intervention (mean [SD] age, 3.2 [1.8] years). The time to clinical cure was significantly shorter in the moxifloxacin eye drop group than in the no intervention group (3.8 vs 5.7 days; difference, -1.9 days; 95% CI, -3.7 to -0.1 days; P = .04), while in the survival analysis both moxifloxacin and placebo eye drops significantly shortened the time to clinical cure relative to no intervention. In the meta-analysis, a total of 584 children were randomized (300 to topical antibiotics and 284 to a placebo), and the use of topical antibiotics was associated with a significant reduction in the proportion of children who had symptoms of conjunctivitis on days 3 to 6 compared with placebo eye drops (odds ratio, 0.59; 95% CI, 0.39 to 0.91)., Conclusions and Relevance: In this randomized clinical trial and systematic review and meta-analysis, topical antibiotics were associated with significantly shorter durations of conjunctival symptoms in children with acute infective conjunctivitis., Trial Registration: ClinicalTrialsRegister.eu Identifier: 2013-005623-16.

What Is Known and Objective: Polypharmacy and age are known to increase the risk for potential drug interactions. Type 2 diabetes has been associated with polypharmacy and several comorbidities. Currently, there is no information on whether the frequency of clinically relevant drug-drug interactions and the risk for drug adverse effects differ between older persons with and without diabetes. The aim of this study was to investigate the frequency of drug-drug interactions and the risk for drug adverse effects in these two groups in primary care., Methods: The basic study population consisted of Finnish home-dwelling primary care patients aged ≥ 65 years (N = 3039). For each person with diabetes, two controls were selected with adjusted age and gender. To collect data, electronic primary care patient records, a structured health questionnaire and a structured health examination conducted by a physician were utilized. Using the SFINX-PHARAO ® database, drug-drug interactions and the risk for drug adverse effects were evaluated in 182 persons with type 2 diabetes and 176 persons without diabetes., Results and Discussion: There were no significant differences in the frequency of drug-drug interactions or the risk for drug adverse effects in persons with and without diabetes. At least one clinically relevant interaction was found in 81 (44.5%) persons with diabetes and 73 (41.5%) persons without diabetes. The most common drugs causing interactions included non-steroidal anti-inflammatory drugs (NSAIDs) and warfarin., What Is New and Conclusion: There is no difference in the frequency of drug-drug interactions or risk for drug adverse effects in older home-dwelling persons with and without diabetes. Due to common comorbidities and commonly used drugs among persons with diabetes, drug-drug interactions involving warfarin or NSAIDs in particular should be carefully monitored to avoid drug adverse effects., (© 2019 John Wiley & Sons Ltd.)

Aim: Our aim was to study prospectively the aetiology of neonatal conjunctivitis in a population-based setting., Methods: Altogether 173 neonates with clinical conjunctivitis aged on average 20 (SD 10) days were recruited from child welfare clinics in Oulu, Finland, in 2010-2015. Conjunctival specimens were collected from 167 neonates for multiplex polymerase chain reaction to detect 16 respiratory viruses, from 163 for polymerase chain reaction to detect Chlamydia trachomatis and Neisseria gonorrhoeae and from 160 for bacterial culture studies. The cases were followed up until the age of 18 months., Results: Viral conjunctivitis was diagnosed in 8/167 (4.8%; 95% CI 2.1-9.2%), chlamydial or gonococcal conjunctivitis in 0/163 cases (0%; 95% CI 0-2.2%) and other bacterial conjunctivitis in 58/160 (36%; 95% CI 29-44%). Rhinovirus was found at the ocular site in 4/167 (2.4%) neonates, adenovirus in 3/167 (1.8%) and bocavirus in 1/167 (0.6%). The most commonly isolated bacteria included Staphylococcus aureus (16%), Moraxella catarrhalis (9.4%) and Streptococcus pneumoniae (3.1%). None of these pathogens was associated with the 4/173 (2.3%) cases later operated on for persistent nasolacrimal duct obstruction., Conclusion: Chlamydia trachomatis was a rare pathogen in neonatal conjunctivitis in a population-based setting, but respiratory viruses were detected more frequently than indicated earlier., (©2018 Foundation Acta Paediatrica. Published by John Wiley & Sons Ltd.)

Objectives: Chlamydia trachomatis colonisation is common in pregnant women, and it has been claimed that mother-to-child transmission may occur in 10%-70% of deliveries. C. trachomatis infections are nevertheless rarely encountered in infants in clinical practice. In order to evaluate the reason for this discrepancy, we designed a nationwide study of the C. trachomatis vertical transmission., Methods: Children with a possible C. trachomatis infection were identified from two national health registries in 1996-2011. Copies of the children's medical records were reviewed and maternal serum bank samples obtained during the index pregnancies were analysed for C. trachomatis antibodies. The risk of vertical transmission was calculated using data from two earlier studies in which nucleic acid amplification test (NAAT) positivity and seroconversion rates among women in the general population were reported., Results: Altogether 206 children had a possible C. trachomatis infection, which represents 0.22 per 1000 live births (95% CI 0.19 to 0.25). The risk of vertical transmission among the estimated 24 901 NAAT-positive mothers was 0.8% (95% CI 0.7 to 0.9). Based on the annual seroconversion rate of maternal antitrachomatis antibodies, the risk of vertical transmission was 1.8% (95% CI 1.5 to 2.0). Altogether 35% of the maternal serum samples obtained in the first trimester of a pregnancy leading to a C. trachomatis infection in the infant were negative, implying that the infection was acquired during pregnancy., Conclusions: C. trachomatis infections in infants were rare, with a population-based occurrence of 0.22 per 1000 live births. The risk of vertical transmission of C. trachomatis in the population was <2%, which is significantly lower than reported earlier., Competing Interests: Competing interests: None declared., (Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/.)

The clinical significance of pneumococcal biofilm formation is largely unknown. To clarify this, we tested whether the ability of pneumococcal clinical isolates to form biofilm in vitro accounts for the diverse clinical outcomes. Clinical pneumococcal isolates were cultured from the nasopharynx (n=106), middle ear effusion (n=43) and blood (n=55) of 204 children altogether. Biofilm formation, assessed by measuring optical density (OD) values in microtitre plates after crystal violet staining, did not differ between the bacteria from different sources (p=0.18), the mean OD values of the isolates being 0.119 [95% confidence interval (CI) 0.100-0.138] in the nasopharynx samples, 0.094 (95% CI 0.069-0.119) in the acute otitis media cases, 0.109 (95% CI 0.077-0.141) in the secretory otitis media cases, 0.122 (95% CI 0.084-0.160) in those with sepsis and 0.175 (95% CI 0.071-0.280) in those with other invasive infections. Serotypes 33 and 14 were the most efficient in forming biofilms, whereas serotypes 3 and 38 were poor biofilm producers. We conclude that the clinical presentation of pneumococcal disease did not differ in relation to biofilm formation in vitro, even though there was marked variation between the clinical isolates and serotypes.

Background: Candida krusei infections are associated with high mortality. In order to explore ways to prevent these infections, we investigated potential routes for nosocomial spread and possible clonality of C. krusei in a haematological unit which had experienced an unusually high incidence of cases., Methods: We searched for C. krusei contamination of the hospital environment and determined the level of colonization in patients and health care workers. We also analyzed the possible association between exposure to prophylactic antifungals or chemotherapeutic agents and occurrence of C. krusei. The C. krusei isolates found were genotyped by pulsed-field electrophoresis method in order to determine possible relatedness of the cases., Results: Twelve patients with invasive C. krusei infection and ten patients with potentially significant infection or mucosal colonization were documented within nine months. We were unable to identify any exogenic source of infection or colonization. Genetic analysis of the isolates showed little evidence of clonal transmission of C. krusei strains between the patients. Instead, each patient was colonized or infected by several different closely related genotypes. No association between medications and occurrence of C. krusei was found., Conclusion: Little evidence of nosocomial spread of a single C. krusei clone was found. The outbreak may have been controlled by cessation of prophylactic antifungals and by intensifying infection control measures, e.g. hand hygiene and cohorting of the patients, although no clear association with these factors was demonstrated.

We have observed the efficiency of antibiotic-releasing polylactide-co-glycolide (PLGA) 80/20 in preventing Staphylococcus epidermidis attachment and biofilm formation in vitro. The aim of the present study was to evaluate the effect of self-reinforced (SR) implants with enhanced antibiotic release on bacterial attachment and biofilm formation rates, and also on growth inhibition of Staphylococcus epidermidis. Cylindrical SR-PLGA+AB specimens (length 30 mm, diameter 3 mm) were examined by scanning electron microscopy (SEM) for attachment of S. epidermidis ATCC 35989 on biomaterial surface and formation of biofilm, after incubating with bacterial suspension of ca. 10 cfu/mL for 1, 3, 7, 14 and 21 days. SR-PLGA and SR-PLGA+AB implants were tested on agar plates by measuring the inhibition distance around implants. On the surface of SR-PLGA+AB, at days 1, 3, 7, 14 and 21, the percentage of areas with not a single bacteria attached, was 88.6%, 71.1%, 73.7%, 73.7%, and 68.4%, respectively. On the areas where bacteria were detected, the number of bacterial cells remained low during whole study period, and no significant increase by time was seen. There was no biofilm observed on 97-99% of the examined areas during the whole study period on SR-PLGA+AB. In agar plates, the SR-PLGA+AB showed inhibition of bacterial growth, with (mean) 53.2 mm diameter of inhibition area with peeled implants and 50.5 mm with non-peeled implants. There was no inhibition seen around implants without ciprofloxacin. Bioabsorbable ciprofloxacin-releasing self-reinforced PLGA (SR-PLGA+AB) was superior to plain SR-PLGA in preventing bacterial attachment, biofilm formation, and also the growth of Staphylococcus epidermidis.

Antibiotic coating systems have been successfully used to prevent bacterial attachment and biofilm formation. Our purpose was to evaluate whether bioabsorbable polylactide-co-glycolide (PLGA) 80/20 on its own, and PLGA together with ciprofloxacin (PLGA+C) have any advantages over titanium in preventing Staphylococcus epidermidis attachment and biofilm formation in vitro. Cylindrical specimens of titanium, PLGA, and PLGA+C in triplicate were examined for S. epidermidis ATCC 35989 attachment and biofilm formation after incubation with a bacterial suspension of about 10(5) cfu/mL for 1, 3, 7, 14, and 21 days, using scanning electron microscopy. Growth inhibition properties of PLGA and PLGA+C cylinders were tested on agar plates. On days 1, 3, and 21, no bacterial attachment was seen in 19.5, 9.2, and 41.4% of the titanium specimens; in 18.4, 28.7, and 34.5% of the PLGA specimens; and in 57.5, 62.1, and 57.5% of the PLGA+C specimens, respectively. During the whole study period, no biofilm was observed on 74-93% of the titanium specimens, 58-78% of the PLGA specimens, and 93-100% of the PLGA+C specimens. PLGA+C showed clear bacterial growth inhibition on agar plates, while PLGA and titanium did not show any inhibition. PLGA+C bioabsorbable material was superior to titanium in preventing bacterial attachment and biofilm formation and may have clinical applicability, for example, in prevention of infection in trauma surgery or in the treatment of chronic osteomyelitis.

Objectives: Xylitol is a sugar alcohol which reduces the growth of Streptococcus pneumoniae and the adherence of pneumococci and Haemophilus influenzae to nasopharyngeal cells. Xylitol prevents acute otitis media but does not decrease nasopharyngeal carriage of pneumococci. We hypothesized that xylitol could affect the surface structures of viable pneumococci, which would further explain the mechanism of action of xylitol in preventing acute otitis media., Methods: We exposed five strains of pneumococci to 0.5%-5% xylitol, 5% glucose, 5% fructose and 5% sorbitol or control medium (brain heart infusion) for 0.5-2 h and examined the ultrastructure of bacteria by electron microscopy., Results: The cell wall of pneumococci became more diffuse, the polysaccharide capsule became ragged and the proportion of damaged pneumococci increased after exposure to xylitol for 2 h, but not after exposure to other sugars or control medium. The phenotype of all pneumococcal strains was opaque before xylitol exposure and became almost transparent both in xylitol and in control medium during the experiment., Conclusions: This study demonstrates further that xylitol has a harmful effect on pneumococci. The observed changes in the polysaccharide capsule and the cell wall of pneumococci could affect the adherence and virulence of pneumococci, explaining the good clinical efficacy of xylitol in the prevention of acute otitis media.

Persistent human papillomavirus (HPV) infection is an established cause of cervical cancer, but the role of other sexually transmitted agents, most notably Chlamydia trachomatis, has not been well defined. The women participating in the population-based cervical cancer screening program in Västerbotten county of Northern Sweden were followed up for up to 26 years to identify 118 women who developed cervical cancer after having had a normal Pap smear (on average 5.6 years later; range 0.5 months-26 years). As controls, we selected another 118 women who were matched by birth cohort, time-point of sampling of the baseline normal smear and who had a normal smear at the time when the corresponding case was diagnosed with cancer. The Pap smears and cervical cancer biopsies were analyzed by PCR for C. trachomatis DNA and for HPV DNA. At baseline, C. trachomatis DNA was present in 8% of cases but not among any one of the controls. The relative risk for cervical cancer associated with past C. trachomatis infection, adjusted for concomitant HPV DNA positivity, was 17.1 (95% CI 2.6-infinity). The presence of C. trachomatis and of HPV were not interrelated. Whereas C. trachomatis was primarily found in specimens taken many years before cancer diagnosis, HPV DNA was associated with a short lag time before cancer diagnosis. Whereas most women who were HPV DNA-positive in the prediagnostic smear were also positive for the same virus in the cervical cancer biopsy, none of the women were positive for C. trachomatis in both the prediagnostic smear and in the subsequent cervical cancer. In conclusion, a prior cervical C. trachomatis infection was associated with an increased risk for development of invasive cervical cancer., (Copyright 2002 Wiley-Liss, Inc.)

Context: Human papillomavirus (HPV) infection has been established as a cause of cervical cancer. Epidemiologic studies suggest that Chlamydia trachomatis infection also confers increased risk for cervical squamous cell carcinoma (SCC). Whether this risk is serotype-specific is unknown., Objective: To study the association between exposure to different C trachomatis serotypes and subsequent development of cervical SCC., Design and Setting: Longitudinal, nested case-control study within a cohort of 530 000 women who provided samples to serum banks in Finland, Norway, and Sweden. The data files were linked to respective national cancer registries., Subjects: One hundred twenty-eight women who had developed invasive cervical SCC at least 12 months following serum donation. Each case had 3 matched controls., Main Outcome Measure: Risk for the development of cervical SCC by IgG antibodies to 10 different C trachomatis serotypes, adjusted for antibodies to HPV types 16, 18, and 33 and for serum cotinine levels., Results: Of specific C trachomatis serotypes, serotype G was most strongly associated with SCC (adjusted odds ratio [OR], 6.6; 95% confidence interval [CI], 1. 6-27.0). Other serotypes associated with SCC were I (OR, 3.8; 95% CI, 1.3-11.0) and D (OR, 2.7; 95% CI, 1.3-5.6). Presence of serum IgG antibodies to more than 1 serotype increased the adjusted ORs for SCC (P<.001 for trend)., Conclusions: Chlamydia trachomatis serotype G is most strongly associated with subsequent development of cervical SCC. Increasing numbers of exposures to different C trachomatis serotypes also increases risk. Our results strengthen the evidence that there is a link between past C trachomatis infection and cervical SCC.

Xylitol is effective in preventing acute otitis media by inhibiting the growth of Streptococcus pneumoniae. To clarify this inhibition we used fructose, which is known to block similar growth inhibition observed in Streptococcus mutans. In addition, we evaluated the efficacy of sorbitol in inhibiting the growth of pneumococci, as sorbitol is widely used for indications similar to those for which xylitol is used. The addition of 5% xylitol to the growth medium resulted in marked growth inhibition, an effect which was totally eliminated in the presence of 1, 2.5, or 5% fructose but not in the presence of 1 or 5% glucose, 1% galactose, or 1% sucrose. This finding implies that xylitol-induced inhibition of pneumococcal growth is mediated via the fructose phosphotransferase system in a way similar to that in which mutans group streptococcal growth is inhibited. The addition of sorbitol at concentrations of 1, 2.5, or 5% to the growth medium did not affect the growth of pneumococci and neither inhibited nor enhanced the xylitol-induced growth impairment. Thus, it seems that xylitol is the only commercially used sugar substitute proven to have an antimicrobial effect on pneumococci.

Nickel allergy is manifested as contact allergic eczema elicited by delayed-type hypersensitivity, the reaction being mediated by T lymphocytes. We examined the T-cell receptor (TCR) beta-chain variable gene segment (Vbeta) use of nickel-induced CD4+ and CD8+ T cells in the peripheral blood of nickel-sensitive and nonsensitized subjects. The results show that each patient had an individual Vbeta repertoire overexpressed, these being in CD4+ cells Vbeta10 and Vbeta13 (in subject A); Vbeta1, Vbeta2, Vbeta13 and Vbeta21 (subject B); Vbeta1 and Vbeta10 (subject C); Vbeta9 and Vbeta19 (subject D). Thus, no single Vbeta gene dominated in a majority of the CD4+ samples. The Vbeta genes overexpressed in patient CD8+ nickel-induced T cells were Vbeta1 (in subject A), Vbeta1 (subject B), Vbeta1 and Vbeta2 (subject C) and Vbeta7 (subject D), domination of Vbeta1 being seen in most of the CD8+ samples (75%). No specific overexpression of any Vbeta genes in the nickel-allergic subjects was found in comparison with the non-sensitized subjects. In conclusion, an individual pattern of restricted Vbeta genes was induced with nickel in CD4+ and CD8+ T cells in each nickel allergy patient.

The study was undertaken to see whether TAP1 and TAP2 (transporter associated with antigen processing) genes are involved in susceptibility to nickel allergy. The products of these genes are important in antigen transport and processing, making them candidates for disease susceptibility. Fifty-five nickel-sensitive and 54 non-sensitive subjects were TAP1- and TAP2-typed by amplification refractory mutation system - polymerase chain reaction. The allele and phenotype frequencies of TAP2B were significantly (p = 0.019 and 0.012, respectively) increased in nickel-sensitive subjects versus controls. Relative risk (RR) for TAP2B was 2.7 and etiological factor (EF) = 0.46. The allele frequency of TAP2C was decreased among the nickel-sensitive subjects versus controls (p = 0.016). RR for TAP2C was 0.18. In conclusion, TAP2B increases the risk for nickel allergy, the results suggesting a considerably high EF.

We wanted to investigate whether rheumatoid arthritis (RA) patients, defined by the American College of Rheumatology (ACR) 1987 criteria and selected from one community by the help of the official Finnish data registers, share the common HLA susceptibility genes. The HLA frequencies of 88 RA patients representing 85% of the prevalent cases of RA in the community were compared with those of 188 healthy controls. Fifty-four per cent of the index cases with RA had DR4 compared with 30% of the healthy controls (P <0.001). The 'RA susceptibility sequence' was found in 75% of the DRB1 genes in the index cases, but it did not correlate with the severity of the disease. The frequency of DR3 was not increased in RA patients but it was associated with features of severe disease, that is, with a high erythrocyte sedimentation rate (P<0.05), extra-articular disease (P<0.01) and prostheses in large joints (P<0.05). According to our results community-based RA patients satisfying the new ACR criteria show the common DR4 association. DR3 was the only HLA allele which showed some disease-modifying effect correlating with the severity of RA.

A close association was found between a specific sequence of HLA-C and psoriasis vulgaris in Finnish patients (chi 2 = 18.4, P = 1.78 x 10(-5)). This sequence codes for alanine at position 73 of the HLA-C molecule in the antigen binding cleft, and alanine may play a role in susceptibility to the disease.

Mixed connective tissue disease (MCTD) and systemic lupus erythematosus (SLE) are autoimmune diseases with a genetic background, and it is reasonable to suggest that aberrations in T cell receptor (TCR) genes could contribute to these diseases, as they play an important role in immune regulation. We studied TCR beta-chain gene segments V beta 8, V beta 11 and C beta with restriction fragment length polymorphism (RFLP) in MCTD and SLE patients and controls. Haplotypes could be assigned in individuals who were homozygous for two or three of these three loci, whereupon the haplotype 2/25/10 (V beta 8/V beta 11/C beta) was found to be under-represented in MCTD (P = 0.029). The frequencies of individual alleles in both groups were similar to those of the controls, whereas the number of homozygotes within V beta 8 gene (23/23 kb and 2/2 kb) was increased in MCTD (P = 0.028). It is concluded that the distribution of TCR beta-chain genes could be aberrant in MCTD and could play a role in susceptibility, whereas the TCR beta-chain gene distribution in the SLE patients did not differ from that of the controls.

Since an association has been reported between nickel allergy and HLA-DQA TaqI restriction fragment length polymorphism, we typed the DQA1 locus by a more precise method to confirm the association and characterize it better. Typing was extended to the DQB1 locus. The loci were typed using polymerase chain reaction and sequence-specific oligonucleotides. The DQA1 allele 0601 was slightly overrepresented among the patients, but the p value was not significant. The frequencies of DQB1 locus alleles did not differ from those of the controls. Thus we were unable to confirm any association between HLA and nickel allergy.

Nickel is the major cause of metal-induced contact allergy. To understand the mechanism of its immune reaction, we studied changes in lymphocyte surface markers during nickel challenge in both allergic and healthy subjects using an in vitro nickel reaction in which the lymphocytes of allergic subjects divide when they are stimulated with nickel sulfate. The lymphocytes were labeled with monoclonal antibodies (MAbs) to cell-surface antigens and studied by flow cytometry. Mononuclear cells from the nickel reaction in vivo were studied from skin biopsy specimens using MAbs and avidin-biotin immunohistochemistry. Nickel-induced lymphoblast transformation occurred in vitro only in cells from nickel-allergic subjects. CD4+ cells and CD45RO+ cells were overrepresented among the lymphoblasts of nickel-sensitive subjects, whereas CD8+ and CD8+CD11b+ and CD4+CD45R+ cells were underrepresented. The lymphoblasts contained T cells with the following activation markers: CD25, HLA-DR, CD26, CD71, Ki-67, and activation-associated antigen detected by the MAb, M21C5, but they were CD30-. CD16+ cells were overrepresented among the lymphoblasts. Nickel-reacting T cells used predominantly the T cell receptor, alpha beta-heterodimer, but no preferential selection of either V beta 5, V beta 6, or V beta 8 was observed. The phenotypes of nickel-reacting cells from cutaneous biopsy specimens were in agreement with the in vitro results.