Thymic gene expression analysis reveals a potential link between HIF-1A and Th17/Treg imbalance in thymoma associated myasthenia gravis

Myasthenia gravis (MG) is an immune-mediated disease frequently associated with thymic changes. Increased T helper 17 (Th17) cell activity and dysfunctional regulatory T (Treg) cells have been demonstrated in subgroups of MG. On the other hand, hypoxia-inducible factor 1 (HIF-1) has been shown to regulate the Th17/Treg balance by inducing Th17 differentiation while attenuating Treg development. To identify the underlying mechanisms of different thymic pathologies in MG development, we evaluated thymic samples from thymoma-associated myasthenia gravis (TAMG), MG with hyperplasia (TFH-MG) and thymoma without MG (TOMA) patients. Differential gene expression analysis revealed that TAMG and TFH-MG cells are associated with different functional pathways. A higher RORC/FOXP3 ratio provided evidence for Th17/Treg imbalance in TAMG potentially related to increased HIF1A. The hypoxic microenvironment in thymoma may be a driver of TAMG by increasing HIF1A. These findings may lead to new therapeutic approaches targeting HIF1A in the development of TAMG.

Thymoma patients with or without myasthenia gravis have increased Th17 cells, IL-17 production and ICOS expression

Thymoma associated myasthenia gravis (TAMG) is a small disease subgroup with autoantibodies against the acetylcholine receptor. The aim of this study was to assess the role of T helper (Th) cells in TAMG compared to thymoma patients without MG (TOMA) and healthy controls (HC). Peripheral blood cells were used for intracellular cytokine measurements and phenotyping of CD4+ Th cells. IL-21 and IL-4 productions and peripheral Th cells were higher in TAMG compared to TOMA patients and HC. Increases of ICOS and Th17 population were detected both in TAMG and TOMA groups. Higher IL-10 and Th1 population have been observed related to thymectomy. ICOS expression and Th17 induced by thymoma may contribute to the development of TAMG.

Clinical trait-specific genetic analysis in Behçet's disease identifies novel loci associated with ocular and neurological involvement

Behçet's disease is a complex inflammatory vasculitis with a broad spectrum of clinical manifestations. The purpose of this study was to investigate the genetics underlying specific clinical features of Behçet's disease. A total of 436 patients with Behçet's disease from Turkey were studied. Genotyping was performed using the Infinium ImmunoArray-24 BeadChip. After imputation and quality control measures, logistic regressions adjusting for sex and the first five principal components were performed for each clinical trait using a case-case genetic analysis approach. A weighted genetic risk score was calculated for each clinical feature. Genetic association analyses of previously identified susceptibility loci in Behçet's disease revealed a genetic association between ocular lesions and HLA-B/MICA (rs116799036: OR = 1.85 [95% CI = 1.35-2.52], p-value = 1.1 × 10-4). The genetic risk score was significantly higher in Behçet's disease patients with ocular lesions compared to those without ocular involvement, which is explained by the genetic variation in the HLA region. New genetic loci predisposing to specific clinical features in Behçet's disease were suggested when genome-wide variants were evaluated. The most significant associations were observed in ocular involvement with SLCO4A1 (rs6062789: OR = 0.41 [95% CI = 0.30-0.58], p-value = 1.92 × 10-7), and neurological involvement with DDX60L (rs62334264: OR = 4.12 [95% CI 2.34 to 7.24], p-value = 8.85 × 10-7). Our results emphasize the role of genetic factors in predisposing to specific clinical manifestations in Behçet's disease, and might shed additional light into disease heterogeneity, pathogenesis, and variability of Behçet's disease presentation across populations.

Identification of new risk loci shared across systemic vasculitides points towards potential target genes for drug repurposing

OBJECTIVES

The number of susceptibility loci currently associated with vasculitis is lower than in other immune-mediated diseases due in part to small cohort sizes, a consequence of the low prevalence of vasculitides. This study aimed to identify new genetic risk loci for the main systemic vasculitides through a comprehensive analysis of their genetic overlap.

METHODS

Genome-wide data from 8467 patients with any of the main forms of vasculitis and 29 795 healthy controls were meta-analysed using ASSET. Pleiotropic variants were functionally annotated and linked to their target genes. Prioritised genes were queried in DrugBank to identify potentially repositionable drugs for the treatment of vasculitis.

RESULTS

Sixteen variants were independently associated with two or more vasculitides, 15 of them representing new shared risk loci. Two of these pleiotropic signals, located close to CTLA4 and CPLX1, emerged as novel genetic risk loci in vasculitis. Most of these polymorphisms appeared to affect vasculitis by regulating gene expression. In this regard, for some of these common signals, potential causal genes were prioritised based on functional annotation, including CTLA4, RNF145, IL12B, IL5, IRF1, IFNGR1, PTK2B, TRIM35, EGR2 and ETS2, each of which has key roles in inflammation. In addition, drug repositioning analysis showed that several drugs, including abatacept and ustekinumab, could be potentially repurposed in the management of the analysed vasculitides.

CONCLUSIONS

We identified new shared risk loci with functional impact in vasculitis and pinpointed potential causal genes, some of which could represent promising targets for the treatment of vasculitis.

Effects of balneological outpatient treatment on clinical parameters and serum cytokine levels in patients with chronic low back pain: a single-blind randomized controlled trial

This study aimed to investigate the effects of balneological outpatient treatment (hydrotherapy and peloidotherapy) on clinical status and serum cytokine levels in patients with chronic low back pain (CLBP). Seventy-four patients with CLBP who accepted to participate to the study were randomly divided into two groups. The study group was given ten sessions (in 2 weeks) of hydrotherapy, peloidotherapy, and home exercise, while the control group was given only home exercise. All patients were assessed before and at the end of therapy, at the 1st and 3rd months. The primary outcomes were pain intensity on the visual analog scale (VAS) (VAS-pain, VAS-rest, VAS-exercise) and Oswestry Disability Index (ODI). The secondary outcome measures included patient's and physician's global assessment (VAS-PGA), (VAS-DGA), finger-to-floor distance (FFD), modified Schober test, Short Form-36 (SF-36), and the use of analgesic drug. Venous blood samples were drawn from all patients before/1st day and after therapy/12th day to measure serum interleukin (IL)-6 and IL-10 levels. Significant improvement was observed in the study group in VAS-pain, VAS-rest, VAS-exercise, VAS-PGA, VAS-DGA, ODI, and SF-36 parameters after treatment and improvement maintained for 3 months. In the control group, significant improvement was observed in VAS-pain, VAS-exercise, VAS-PGA, VAS-DGA, and ODI scores on the 12th day and continued for 3 months. Decrease in pain, pain during rest and exercise, modified Schober test, VAS-PGA, VAS-DGA, ODI scores, and the increase in SF-36 pain and general health scores showed superiority in favor of the study group in all evaluations. There was a significant increase in IL-10 values from baseline at the end of treatment in the study group. The use of non-steroidal anti-inflammatory drug (NSAID) was significantly lower in the study group compared with the use of NSAID in the control group in the 3rd month. Balneological outpatient treatment improved clinical status in CLBP patients. Although no significant correlation was clearly determined between IL-10 levels and pain score, this effect might be related to the observed increase in the anti-inflammatory cytokine IL-10 levels that was observed only in the study group.

The treatment effect on peripheral B cell markers in antibody positive myasthenia gravis patients

B cells play a major role in the pathophysiology of myasthenia gravis (MG) with their ability to produce disease specific, pathogenic antibodies. However, their status during disease development and follow-up stages of the disease in the peripheral blood may need further studies to determine useful markers. In this study, we aimed to detect B cell associated factors concerning immunosuppressive treatment in generalized non-thymomatous MG patients. Although CD19⁺ B cell distribution did not vary among disease subgroups, expressions of both CD38 and BAFFR were altered on B cells in MG patients under immunosuppressive therapy. Serum levels of BAFF were elevated in untreated MG patients as compared to treated MG patients and healthy controls. B cell activation factors may show profound alterations due to immunosuppression.

Relation of HLA-DRB1 to IgG4 autoantibody and cytokine production in muscle-specific tyrosine kinase myasthenia gravis (MuSK-MG)

A small subset of myasthenia gravis (MG) patients develop autoantibodies against muscle-specific kinase (MuSK), which are predominantly of the immunoglobulin (Ig)G4 isotype. MuSK-MG is strongly associated with HLA-DRB1*14, HLA-DRB1*16 and HLA-DQB1*05. In this study, the possible effects of these HLA associations on MuSK IgG autoantibody or cytokine production were investigated. Samples from 80 MG patients with MuSK antibodies were studied. The disease-associated HLA types were screened in the DNA samples. The IgG1, IgG2, IgG3 and IgG4 titres of the MuSK antibodies and the levels of interleukin (IL)-4, IL-6, IL-17A and IL-10 were measured in the sera. Comparisons were made among the groups with or without HLA-DRB1*14, HLA-DRB1*16 or HLA-DQB1*05. The IgG4 titres of the MuSK antibodies were higher than those of the IgG1, IgG2 and IgG3 isotypes among the whole group of patients. DRB1*14 (+) DRB1*16 (-) patients had higher levels of IgG4 antibodies than those of DRB1*14 (-) DRB1*16 (+) patients. DRB1*14 (+) DRB1*16 (+) patients also had higher levels of IgG4 antibodies than those of DRB1*14 (-) DRB1*16 (+) and DRB1*14 (-) DRB1*16 (-) patients. Higher IL-10 and lower IL-17A levels were measured in DRB1*14 (+) DRB1*16 (-) patients than in DRB1*14 (-) DRB1*16 (-) patients. The higher IgG4 titres of MuSK autoantibodies in patients carrying HLA-DRB1*14 than those in the other patients suggest a role for HLA in the production of the antibodies. The differences in IL-10 and IL-17A support the role of DRB1 in the etiopathogenesis of this autoimmune response.

The effect of interleukin (IL)-21 and CD4+ CD25++ T cells on cytokine production of CD4+ responder T cells in patients with myasthenia gravis

Impairment of the suppressive function of regulatory T (T_reg ) cells has been reported in myasthenia gravis (MG). In this study, cytokine-related mechanisms that may lead to the defect of T_reg were investigated in patients with anti-acetylcholine receptor antibody-positive MG (AChR + MG). Proliferation and cytokine production of responder T (T_resp ) cells in response to polyclonal activation were measured in a suppression assay. The effect of interleukin (IL)-21 on suppression was evaluated in vitro in co-culture. IL-21 increased the proliferation of T_resp cells in T_resp /T_reg co-cultures. T_resp cells from patients with MG secreted significantly lower levels of IL-2. In patients with MG, IL-2 levels did not change with the addition of T_reg to cultures, whereas it decreased significantly in controls. In T_resp /T_reg co-cultures, IL-4, IL-6 and IL-10 production increased in the presence of T_reg in patients. Interferon (IFN)-γ was decreased, whereas IL-17A was increased in both patient and control groups. IL-21 inhibited the secretion of IL-4 in MG and healthy controls (HC), and IL-17A in HC only. The results demonstrated that IL-21 enhances the proliferation of T_resp cells in the presence of T_reg . An effect of IL-21 mainly on T_resp cells through IL-2 is implicated.

Titin antibodies in "seronegative" myasthenia gravis--A new role for an old antigen

Myasthenia gravis (MG) is an autoimmune disease caused by antibodies targeting the neuromuscular junction of skeletal muscles. Triple-seronegative MG (tSN-MG, without detectable AChR, MuSK and LRP4 antibodies), which accounts for ~10% of MG patients, presents a serious gap in MG diagnosis and complicates differential diagnosis of similar disorders. Several AChR antibody positive patients (AChR-MG) also have antibodies against titin, usually detected by ELISA. We have developed a very sensitive radioimmunoprecipitation assay (RIPA) for titin antibodies, by which many previously negative samples were found positive, including several from tSN-MG patients. The validity of the RIPA results was confirmed by western blots. Using this RIPA we screened 667 MG sera from 13 countries; as expected, AChR-MG patients had the highest frequency of titin antibodies (40.9%), while MuSK-MG and LRP4-MG patients were positive in 14.6% and 16.4% respectively. Most importantly, 13.4% (50/372) of the tSN-MG patients were also titin antibody positive. None of the 121 healthy controls or the 90 myopathy patients, and only 3.6% (7/193) of other neurological disease patients were positive. We thus propose that the present titin antibody RIPA is a useful tool for serological MG diagnosis of tSN patients.

Identification of Susceptibility Loci in IL6, RPS9/LILRB3, and an Intergenic Locus on Chromosome 21q22 in Takayasu Arteritis in a Genome-Wide Association Study

OBJECTIVE

Takayasu arteritis is a rare large vessel vasculitis with incompletely understood etiology. This study was undertaken to perform the first unbiased genome-wide association analysis of Takayasu arteritis.

METHODS

Two independent cohorts of patients with Takayasu arteritis from Turkey and North America were included in our study. The Turkish cohort consisted of 559 patients and 489 controls, and the North American cohort consisted of 134 patients and 1,047 controls of European ancestry. Genotyping was performed using the Omni1-Quad and Omni2.5 genotyping arrays. Genotyping data were subjected to rigorous quality control measures and subsequently analyzed to discover genetic susceptibility loci for Takayasu arteritis.

RESULTS

We identified genetic susceptibility loci for Takayasu arteritis with a genome-wide level of significance in IL6 (rs2069837) (odds ratio [OR] 2.07, P = 6.70 × 10(-9)), RPS9/LILRB3 (rs11666543) (OR 1.65, P = 2.34 × 10(-8)), and an intergenic locus on chromosome 21q22 (rs2836878) (OR 1.79, P = 3.62 × 10(-10)). The genetic susceptibility locus in RPS9/LILRB3 lies within the leukocyte receptor complex gene cluster on chromosome 19q13.4, and the disease risk variant in this locus correlates with reduced expression of multiple genes including the inhibitory leukocyte immunoglobulin-like receptor gene LILRB3 (P = 2.29 × 10(-8)). In addition, we identified candidate susceptibility genes with suggestive levels of association (P < 1 × 10(-5)) with Takayasu arteritis, including PCSK5, LILRA3, PPM1G/NRBP1, and PTK2B.

CONCLUSION

Our findings indicate novel genetic susceptibility loci for Takayasu arteritis and uncover potentially important aspects of the pathophysiology of this form of vasculitis.

Serum cytokine profiles in Takayasu's arteritis: search for biomarkers

OBJECTIVES

Assessment of disease activity is one of the major difficulties in patients with Takayasu arteritis (TAK) during follow-up. To date, no biomarker is universally accepted to be a surrogate for active disease in TAK. In this study, we aimed to investigate levels of various pro-and anti-inflammatory molecules including serum granulocyte-macrophage colony-stimulating factor (GM-CSF), interleukin (IL)-6, IL-8, IL-10, IL-18 and IL-23 in patients with TAK.

METHODS

The study included 51 patients (age: 40.6±12.2 years, F/M: 45/6) with TAK and 42 age- and sex-matched healthy controls (age: 38.1±7.4 years, F/M: 38/4). All patients fulfilled the criteria of the American College of Rheumatology (ACR). TAK patients were evaluated by physician's global assessment (PGA; active/inactive) and ITAS2010 (Indian Takayasu Arteritis Clinical Activity Score) in terms of clinical activity in baseline and follow-up visits. Commercial enzyme linked immuno-sorbent assay (ELISA) kits were used for measurements of serum cytokine levels.

RESULTS

At baseline, 21 (41.2%) patients were active according to PGA and 8 (15.7%) according to ITAS2010. Serum IL-6, IL-8 and IL-18 levels were significantly higher in patients with TAK, whereas GM-CSF, IL-10, IL-23 levels were similar to healthy controls. IL-8 significantly decreased in the follow-up, associated with a decrease of clinical activity, whereas IL-23 level significantly increased. When assessed by ITAS2010 active patients had significantly higher IL-18 levels.

CONCLUSIONS

We found significantly increased IL-6, IL-8 and IL-18 levels in patients with TAK compared to healthy controls. Only IL-18 level was significantly higher in active patients assessed by ITAS2010. IL-18 was also the only cytokine in our study that correlated with CRP. These findings suggest that cytokines associated with neutrophilic, pro-inflammatory responses such as IL-6, IL-8 and IL-18 can be potential biomarkers for the assessment of disease activity in TAK and warrant further studies in larger series.

A comprehensive analysis of the epidemiology and clinical characteristics of anti-LRP4 in myasthenia gravis

Double-seronegative myasthenia gravis (dSN-MG, without detectable AChR and MuSK antibodies) presents a serious gap in MG diagnosis and understanding. Recently, autoantibodies against the low-density lipoprotein receptor-related protein 4 (LRP4) have been identified in several dSN-MG sera, but with dramatic frequency variation (∼2-50%). We have developed a cell based assay (CBA) based on human LRP4 expressing HEK293 cells, for the reliable and efficient detection of LRP4 antibodies. We have screened about 800 MG patient sera from 10 countries for LRP4 antibodies. The overall frequency of LRP4-MG in the dSN-MG group (635 patients) was 18.7% but with variations among different populations (range 7-32.7%). Interestingly, we also identified double positive sera: 8/107 anti-AChR positive and 10/67 anti-MuSK positive sera also had detectable LRP4 antibodies, predominantly originating from only two of the participating groups. No LRP4 antibodies were identified in sera from 56 healthy controls tested, while 4/110 from patients with other neuroimmune diseases were positive. The clinical data, when available, for the LRP4-MG patients were then studied. At disease onset symptoms were mild (81% had MGFA grade I or II), with some identified thymic changes (32% hyperplasia, none with thymoma). On the other hand, double positive patients (AChR/LRP4-MG and MuSK/LRP4-MG) had more severe symptoms at onset compared with any single positive MG subgroup. Contrary to MuSK-MG, 27% of ocular dSN-MG patients were LRP4 antibody positive. Similarly, contrary to MuSK antibodies, which are predominantly of the IgG4 subtype, LRP4 antibodies were predominantly of the IgG1 and IgG2 subtypes. The prevalence was higher in women than in men (female/male ratio 2.5/1), with an average disease onset at ages 33.4 for females and 41.9 for males. Overall, the response of LRP4-MG patients to treatment was similar to published responses of AChR-MG rather than to MuSK-MG patients.

TIR-domain-containing adaptor protein gene TIRAP S180L polymorphism is not increased in Behçet's disease patients in two ethnic cohorts

OBJECTIVES

The single nucleotide polymorphism (SNP) of TIRAP (Serine 180 leucine, S180L) that is shown to be associated with Behçet's disease (BD) in a European-derived cohort, but not in Middle Eastern patients is investigated in two other populations.

METHODS

Two cohorts of BD patients and controls from Turkey (n=797) and Italy (n=633) were genotyped by sequence specific primer-polymerase chain reaction (SSP-PCR) or TaqMan q-PCR assays.

RESULTS

Genotype and allele frequencies in TIRAP S180L (rs8177374) were not different between BD patients and controls in either ethnicity. Furthermore, a meta-analysis between the Turkish and the Italian BD cohorts did not reveal an association between this non-synonymous SNP in TIRAP and BD (meta-analysis OR=0.94, meta-analysis p=0.61, Q statistic heterogeneity p=0.11).

CONCLUSIONS

TIRAP S180L gene polymorphism, which was previously shown to be associated with BD in a Caucasian population, has been replicated in either Turkish or Italian population in our study.

Intrathecal oligoclonal IgG bands are infrequently found in neuro-Behçet's disease

OBJECTIVES

Oligoclonal bands (OCB) of immunoglobulins (IgG) in the cerebrospinal fluid (CSF) provides an evidence for the humoral response and have been screened in the CSF and serum of patients revealing 5 different patterns. In this study, patients with Behçet's disease (BD) are screened in a larger sample to potentially provide information about the possible role of CSF oligoclonal immunoglobulins in the diagnosis of this disease.

METHODS

Paired CSF and serum samples from 121 consecutive BD patients with neurological complaints (43 women and 78 men) were included in this study. Parenchymal NBD was diagnosed in 74 patients, and 22 patients had cerebral venous sinus thrombosis (CVST); of the remaining patients, 18 had primary headache disorders not directly associated with BD, and 7 had a cerebrovascular event. OCB of IgG were detected by isoelectric focusing on agarose and immunoblotting of matched serum and CSF sample pairs. Intrathecal production of IgG only is considered positive (Pattern 2 or 3).

RESULTS

In the whole group, only 8 patients had OCB in the CSF showing pattern 2. All these positive cases had parenchymal neuro-BD (10.8% positive and 78.4% negative in parenchymal neuro-BD group). All other groups were negative.

CONCLUSIONS

The rare presence of oligoclonal IgG bands in CSF can be utilized as another laboratory finding in the diagnosis of NBD.

Expression of regulatory receptors on γδ T cells and their cytokine production in Behcet's disease

INTRODUCTION

Behcet's disease (BD) is a multi-systemic disorder with muco-cutaneous, ocular, arthritic, vascular or central nervous system involvement. The role of γδ T cells is implicated in BD. The activation status of γδ T cells and their cytokine secretion against phosphoantigens are evaluated in BD.

METHODS

NKG2A, NKG2C, NKG2D, CD16 and CCR7 molecules on γδ T cells were analyzed in 70 BD, 27 tuberculosis (TB) patients and 26 healthy controls (HC). Peripheral γδ T cells were expanded with a phosphoantigen (BrHPP) and IL-2, restimulated with BrHPP and a TLR3 ligand, and cytokine production was measured.

RESULTS

γδ T cells were not increased in both BD and TB patients, but the proportions of TCRVδ2+ T cells were lower (58.9 and 50.7 vs. 71.7%, P=0.04 and P=0.005) compared to HC. Higher proportion of TCRVδ2+ T cells were CD16+ (26.2 and 33.9 vs. 16.6%, P=0.02 and P=0.001) and CCR7- (32.2 and 27.9 vs. 17.7%, P<0.0001 and P=0.014) in BD and TB patients compared to HC. NKG2C+ γδ+ T cells were relatively increased (0.5 and 0.6 vs. 0.3%, P=0.008 and 0.018), whereas NKG2D positivity was decreased in patients with BD and TB (77.7 and 75.8 vs. 87.5%, P=0.001 and 0.004). Expansion capacity of γδ T cells in BD and TB as well as production of IL-13, IFN-γ, granulocyte monocyte colony stimulating factor (GM-CSF), TNF-α, CCL4 and CCL5 in BD was lower compared to HC, when restimulated by TLR3 ligand and BrHPP.

CONCLUSION

The changes on γδ T cells of BD as well as TB patients implicate that γδ T cells have already been exposed to regulatory effects, which changed their activity. Lower cytokine response of γδ T cells implicates down modulation of these cells in BD.

PDCD1 polymorphisms are not associated with Takayasu's arteritis in Turkey

OBJECTIVES

Takayasu's arteritis (TA) is a chronic arterial inflammation of unknown etiology involving mainly the aorta and its major branches. Based on the associations of programmed death-1 (PD-1) protein encoding gene (PDCD1) with connective tissue diseases and vasculitides, PDCD1 polymorphisms are studied for susceptibility to TA in this study.

METHODS

The study group is made up of TA patients (n=229) fulfilling the 1990 ACR classification criteria and compared to 193 healthy controls (HC). PD-1.3, PD-1.5 and PD-1.6 single nucleotide polymorphisms of PDCD1 gene are genotyped by polymerase chain reaction and restriction analysis (PCR-RFLP).

RESULTS

The distribution of PD-1.5 polymorphism in TA patients and HC revealed a similar presence of TT genotype in patients and controls (13.3% vs. 11.4%). PD-1.3 and PD-1.6 were less polymorphic and did not differ between the groups. Rare AA genotype of PD-1.3 (1.4% vs. 1.0%) and AG genotype of PD-1.6 was again similarly (22.4% vs. 19.2%) present in TA and HC.

CONCLUSIONS

PD-1.3, 1.5 and 1.6 polymorphisms of PDCD1 gene, which were shown to be associated with various autoimmune disorders and vasculitides, are not associated with a susceptibility to TA in Turkish population.

COMT Val 158 Met polymorphism is related with interpersonal problem solving in schizophrenia

OBJECTIVE

The aim of this study was to investigate associations between COMT Val(158)Met polymorphism, and interpersonal problem solving capacity and cognitive functions in schizophrenia.

METHODS

COMT Val(158)Met polymorphism was studied with ARMS-PCR method in 99 outpatients with schizophrenia. Brief Psychiatric Rating Scale was used to assess symptom severity. The Assessment of Interpersonal Problem Solving Skills (AIPSS) was used to evaluate problem solving capacity. Continuous Performance Test (CPT) and Wisconsin Card Sorting Test (WCST), were used to measure cognition.

RESULTS

Patients with Met/Met genotype had higher AIPSS subscores for detecting the problem, than those with Val/Val at baseline (p=0.02). Met allele was also found to be related with higher AIPSS-receiving skills (p=0.04). Val allele was found to be related with more commission errors in CPT (p=0.03). There was no relation between Val(158)Met polymorphism and WCST and clinical measurements.

CONCLUSION

Our findings suggest that Val allele might be related to poor performance on detecting the interpersonal problems, and attention in schizophrenia.

The role of osteopontin: a shared pathway in the pathogenesis of multiple sclerosis and osteoporosis?

Osteopontin (OPN) was suggested to have a role in the pathophysiology of MS and in bone metabolism. However, we formerly reported increased presence of osteoporosis in MS patients independent of corticosteroid treatment, there is only limited information about the mechanism of bone loss. In this study, we investigated the role of OPN on bone mineral density in MS patients. Thirty-three relapsing-remitting (RR), 12 secondary progressive (SP), and 5 primary progressive (PP) MS patients and 30 healthy controls were prospectively enrolled. Students' t test, chi-square test, and Pearson correlations were used. The mean OPN level was 155.4+/-81.8 ng/ml in controls, and 15.9+/-36.2 ng/ml in MS patients (p<0.001).No statistical difference was observed among RR, SP and PPMS patients (p=0.162). No relationship was found between OPN levels and age at onset of disease (p=0.830), gender (p=0.785), MS subtypes (p=0.330), disease duration (p=0.744), or EDSS scores (p=0.633).About 34% of MS patients versus 10.3% of controls had osteoporosis (p=0.017).Osteopontin levels showed no significant correlation with osteoporosis in controls, but were lower in MS patients with osteoporosis in femur neck (r=0.85, p=0.010).The cumulative dose of corticosteroid treatment did not correlate with OPN levels (p=0.285).In conclusion, our results suggest that OPN may have a role as a shared cytokine in pathogenesis of MS and osteoporosis.

PTPN22 gene polymorphism in Takayasu's arteritis

OBJECTIVE

Takayasu's arteritis (TA) is a chronic, rare granulomatous panarteritis of unknown aetiology involving mainly the aorta and its major branches. In this study, genetic susceptibility to TA has been investigated by screening the functional single nucleotide polymorphism (SNP) of PTPN22 gene encoding the lymphoid-specific protein tyrosine phosphatase.

METHODS

Totally, 181 patients with TA and 177 healthy controls are genotyped by PCR-RFLP method for the SNP rs2476601 (A/G) of PTPN22 gene. Polymorphic region was amplified by PCR and digested with Xcm I enzyme.

RESULTS

Detected frequencies of heterozygous genotype (AG) were 5.1% (9/177) in control group and 3.8% (7/181) in TA group (P = 0.61, odds ratio: 0.75, 95% CI: 0.3, 2.0). No association with angiographic type, vascular involvement or prognosis of TA was observed either.

CONCLUSION

The distribution of PTPN22 polymorphism did not reveal any association with TA in Turkey.

The role of HLA-DRB1 shared epitope alleles in predicting short-term response to leflunomide in rheumatoid arthritis

OBJECTIVES

To investigate the role of shared epitope (SE) alleles in the short-term clinical response to leflunomide for the treatment of active RA.

METHODS

In an open-label, multi-centre study of 16-weeks duration, 93 patients (82% female) fulfilling ARA 1987 RA criteria were treated with leflunomide (100 mg loading dose for 3 days, then 20 mg/day as the maintenance dose). The primary efficacy criterion was the response status according to the European League Against Rheumatism (EULAR) response criteria using Disease Activity Score-28 (DAS28) activity measure. SE determinations have been undertaken by polymerase chain reaction and sequence-specific oligonucleotide genotyping methods.

RESULTS

The mean (s.d.) Disease Activity Score-28 (DAS28) was 5.1 (1.3) before the treatment, which was significantly decreased after 16 weeks [3.0 (1.1), P < 0.001]. According to the EULAR response criteria, 55 patients (59.1%) were classified as good responders. SE was positive in 51 (54.8%) of the patients, with 13 (13.9%) having SE homozygosity or carrying any two SE alleles. Among SE-positive patients, 68.6% (35/51) were good responders, compared with 47.6% (20/42) in SE negatives (P = 0.04). No difference was present according to SE hetero- or homozygosity (68.4 vs 69.2%). RF was also present significantly more frequently in the SE-positive group compared with negatives (78.4 vs 57.1%, P = 0.03). However, no significant difference was observed in the prevalence of RF positivity in patients with a good clinical response (72.7 vs 63.2%, P = 0.32).

CONCLUSIONS

The results suggest that HLA-DRB1 SE presence may favourably affect the outcome of leflunomide monotherapy in an unselected group of RA patients with an active disease and naive to leflunomide.

PTPN22 gene polymorphism in Behçet's disease

A functional single nucleotide polymorphism (SNP) of PTPN22 gene encoding the protein tyrosine phosphatase has been reported to be associated with autoimmune disorders such as rheumatoid arthritis, systemic lupus erythematosus and type I diabetes. PTPN22 R620W polymorphism has a wide variation of allelic frequencies among different populations. This polymorphism is investigated in Turkish patients with Behçet's disease (BD), a systemic vasculitis with immune activation. DNA samples from 134 patients with BD and 177 healthy controls are genotyped by polymerase chain reaction (PCR)-restriction fragment length polymorphism method for the SNP (rs2476601, A/G) of PTPN22 gene. Polymorphic region was amplified by PCR and digested with XcmI enzyme. The frequency of heterozygous genotype (AG) was 5.1% (9/177) in control group, whereas polymorphic allele was not present in the whole BD group (P = 0.012, OR 0.65, 95% confidence interval 0.0-1.1). Both the lower prevalence in the general population and the absence in BD show the limited role of PTPN22 polymorphism in the pathogenesis of autoimmunity in Turkey.

Relative predispositional effects of HLA class II DRB1-DQB1 haplotypes and genotypes on type 1 diabetes: a meta-analysis

The direct involvement of the human leukocyte antigen class II DR-DQ genes in type 1 diabetes (T1D) is well established, and these genes display a complex hierarchy of risk effects at the genotype and haplotype levels. We investigated, using data from 38 studies, whether the DR-DQ haplotypes and genotypes show the same relative predispositional effects across populations and ethnic groups. Significant differences in risk within a population were considered, as well as comparisons across populations using the patient/control (P/C) ratio. Within a population, the ratio of the P/C ratios for two different genotypes or haplotypes is a function only of the absolute penetrance values, allowing ranking of risk effects. Categories of consistent predisposing, intermediate ('neutral'), and protective haplotypes were identified and found to correlate with disease prevalence and the marked ethnic differences in DRB1-DQB1 frequencies. Specific effects were identified, for example for predisposing haplotypes, there was a statistically significant and consistent hierarchy for DR4 DQB1*0302s: DRB1*0405 =*0401 =*0402 > *0404 > *0403, with DRB1*0301 DQB1*0200 (DR3) being significantly less predisposing than DRB1*0402 and more than DRB1*0404. The predisposing DRB1*0401 DQB1*0302 haplotype was relatively increased compared with the protective haplotype DRB1*0401 DQB1*0301 in heterozygotes with DR3 compared with heterozygotes with DRB1*0101 DQB1*0501 (DR1). Our results show that meta-analyses and use of the P/C ratio and rankings thereof can be valuable in determining T1D risk factors at the haplotype and amino acid residue levels.

Clinical comparison of anti-MuSK- vs anti-AChR-positive and seronegative myasthenia gravis

We compared 65 anti-acetylcholine receptor (AChR)-negative myasthenia gravis (MG) patients, including 32 anti-muscle-specific tyrosine kinase (MuSK)-positive (49%) and 33 anti-MuSK-negative (seronegative) (51%) patients, with 161 anti-AChR-positive MG patients. The anti-MuSK-positive group had a higher frequency of bulbar involvement and respiratory crises. The seronegative group was in between the anti-MuSK positive and the anti-AChR positive groups, being closer to the latter, with regard to the severity of the disease. At the end of follow-up, the outcome of the anti-MuSK-positive patients was not different from that of the anti-AChR-positive patients, although their maintenance corticosteroid dose was higher. The seronegative patients had better outcome than the other two groups.

Interleukin (IL)-12, IL-2, and IL-6 gene polymorphisms in Takayasu's arteritis from Turkey

Takayasu's arteritis (TA) is a chronic arterial inflammation of unknown etiology involving mainly the aorta and its major branches. Genetic polymorphisms of cytokines are screened as susceptibility factors for TA in Turkey. A total of 94 patients with TA were investigated for the genetic polymorphisms of the interleukin genes IL12, IL2,and IL6 and were compared with 108 healthy control subjects using polymerase chain reaction-sequence-specific primer method. The frequencies of IL12B 1188 C allele (p = 0.03, OR = 1.7) and CC genotype (p = 0.007, OR = 3.7) were both higher in TA patients than in control subjects. TT genotype at IL2-330 (p = 0.006, OR = 2.4) and GG genotype at IL6-174 (p = 0.04, OR = 1.9) were more frequent in TA patients. Lower prevalence of GT genotype at IL2-330 (p = 0.005, OR = 0.4), CG genotype at IL6-174 (p = 0.001, OR = 0.4), and AG genotypes at IL6-598 (p = 0.01, OR = 0.4) were also detected. The polymorphism of IL-12 as well as IL-6 and IL-2 genes may contribute to susceptibility and pathogenesis of TA by altering cytokine production and inducing inflammation.

Inflammatory/demyelinating central nervous system involvement in familial Mediterranean fever (FMF): coincidence or association?

BACKGROUND AND OBJECTIVE

Familial Mediterranean fever (FMF) is an inherited inflammatory disease characterized by recurrent febrile polyserositis. Central nervous system (CNS) involvement in FMF is uncommon, but recently cases with multiple sclerosis (MS) and FMF have been reported. Here we assess patients with both FMF and MS, in order to clarify any relationship between FMF and MS, and to evaluate disease characteristics.

PATIENTS AND METHODS

Our MS database between 1986-2005 was screened retrospectively, and patients with both FMF and inflammatory/demyelinating CNS disease were evaluated among a total of 2800 patients including definite MS (n = 2268) and other demyelinating disorders.

RESULTS

There were 12 patients with FMF, who developed a CNS disorder with multifocal white matter lesions. Median age at onset of FMF was 7 years, and median age at neurological onset was 26.8 years. Nine patients (including two siblings) had definite MS according to clinical and MRI findings, whereas 3 patients had atypical features suggesting other demyelinating disorders. Disease severity varied among the patients between very mild to a fatal course. All 8 patients evaluated for oligoclonal IgG bands in CSF were positive.

CONCLUSION

The rate of FMF among our patients with definite MS is almost 4 times the expected prevalence in Turkey. Our series including a sibling pair concordant for FMF and MS may suggest that similar genetic susceptibility and environmental factors might be responsible, although coincidence still remains a possibility. A prospective study on a larger sample seems to be justified.

Human leukocyte antigen-A, -B and -C alleles and human leukocyte antigen haplotypes in Turkey: relationship to other populations

In this study, we present, for the first time, human leukocyte antigen (HLA) class I allele and haplotype frequencies at the DNA level in a sample of 142 donors from Turkey. HLA typing was performed by medium-to-high resolution polymerase chain reaction sequence-specific oligonucleotide probes method. The most frequent HLA alleles at class I locus were A*0201(0.257), -B*35(0.204) and -Cw*04(0.173). A*0201-B*35-Cw*04(0.056) was the most common three-locus haplotype. Allele and haplotype frequency comparisons and neighbour-joining dendrograms, constructed using DA genetic distances and correspondence analysis using HLA-A, -B and -C, and -DRB1 allele frequencies, revealed similarities with other Mediterranean and European populations, but not with Mongol populations. These results agree with previous studies and confirm that the present day Turkish population is genetically more similar to its geographic neighbours than its historical neighbours in central Asia. The comprehensive HLA data on the Turkish population at the DNA level including up to six-locus putative haplotypes generated in this study will be useful for further studies.

Common Crohn's disease-predisposing variants of the CARD15/NOD2 gene are not associated with Behçet's disease in Turkey

OBJECTIVE

There are many extra-intestinal findings of Crohn's disease (CD), such as oral and genital ulcers, erythema nodosum, uveitis and arthritis, resembling the manifestations of Behçet's disease (BD). It is also very difficult to distinguish the gastrointestinal involvement of BD from that of CD in some patients. Hence, this study aimed to investigate a possible involvement of the common CD-predisposing CARD15 variants in the genetic susceptibility to BD.

METHODS

The study group consisted of 85 consecutive patients with BD (51 male, 34 female) of Turkish origin. Two of them had intestinal involvement. A group of 100 ethnically matched, non-related healthy volunteers were used as controls. All individuals were genotyped for 3 common CARD15 variants (R702W, G908R, and Ll007fsinsC) using a polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) method.

RESULTS

None of the three CARD15 variants predisposing to CD was observed in patients with BD, including two patients with intestinal involvement. The R702W mutation was observed in I healthy chromosome, and the 3020insC mutation in 2 chromosomes. No individual was found to be homozygous or compound heterozygous for these variants.

CONCLUSION

These findings suggest that 3 most common CD-predisposing CARD15 variants do not constitute a genetic susceptibility factor for BD in Turkey. Further studies would be helpful to rule out a possible contribution of other rare or unknown variants and/or the effects of different ethnic backgrounds.

Expression of KIR and C-type lectin receptors in Behcet's disease

OBJECTIVE

Behçet's disease (BD) is a multisystemic disorder with a possible underlying pathology of immune-mediated vasculitis. Genetic susceptibility associated with HLA-B*51 and B*2702 has been implicated in its pathogenesis. Considering the recently defined regulatory mechanisms of NK cells through HLA class I binding receptors, we hypothesized that interactions of NK and T cells through the NK receptors may be important in the pathogenesis of BD.

METHODS

The impact of different expression patterns of HLA-recognizing receptors on NK or T cells was analysed in 51 patients with BD and 32 healthy controls. We used flow cytometry to investigate the expression of KIR3DL1 from the polymorphic killer immunoglobulin-like receptor (KIR) family, which binds a shared HLA-Bw4 motif on HLA-B51 and *2702 alleles, and CD94 from the conserved C-type lectin receptor family, which binds HLA-E. Thirty-three of the BD patients and 19 of the controls carried the same HLA-Bw4 motif.

RESULTS

CD3(+) T cells were increased in patients with BD compared with controls (81 vs 75%, P = 0.001), whereas the NK cells did not show any difference between the two groups. Increased expression of CD94 in BD was observed on CD16(+)CD56(+) cells (66 vs 57, P = 0.04) and on CD3(+) (7.7 vs 4.0, P < 0.001) and CD3(+)CD56(+) (44 vs 35, P = 0.02) T cells. KIR3DL1 expression on the NK and T cells was not statistically different between the two groups. No effect of HLA-Bw4 motif was observed on the expression of CD94 and KIR3DL1 in both the patients and the controls.

CONCLUSION

The absence of a correlation between KIR3DL1 expression and HLA-Bw4 motif confirms previous work reporting that the expression of these molecules is regulated separately. Increased expression of CD94 may suggest that NK receptors play a pathogenic or regulatory role in BD.

A genome screen for linkage disequilibrium in Turkish multiple sclerosis

In order to screen the Turkish population for evidence of association with multiple sclerosis, we typed 6000 microsatellite markers in separately pooled DNA samples from 197 cases and 199 controls following the Genetic Analysis of Multiple sclerosis in EuropeanS (GAMES) protocol. Twelve markers showing evidence for association were identified. One of these markers lying directly in a region which is also implicated in the Turkish linkage screen (chromosome 5p15) and thus shows evidence for both linkage and association in independent data sets.

The role of heat shock proteins in Behçet's disease

Heat shock proteins (HSP) are highly conserved molecules with scavenger activity that are involved in the correct folding of newly synthesized proteins. Increased T and B cell activity against 60/65 kD HSP is observed in different ethnic populations in Behçet's disease (BD) with both alpha beta and gamma delta T cell responses. Although the specificity of these responses is not clear, animal models of uveitis treated with either subcutaneous and oral HSP-derived peptides suggest a significant role of HSPs in the immunopathogenesis of BD. Recent developments in the innate immune system with the description of toll-like receptors (TLR) and HSP60 as a ligand for TLR-2 and TLR-4 suggest also the role of HSP60 as an endogenous "danger" signal to the immune system with rapid inflammatory cytokine release and the enhancement of adaptive Th1-type responses. Activation of both innate and adaptive responses with HSPs also fit well into the clinical spectrum of BD with both early, limited responses (recurrent ulcers, pathergy, etc.) and chronic lesions (posterior uveitis, thrombosis, neuro-BD, etc.).

Tumour necrosis factor-alpha gene promoter region -308 and -376 G-->A polymorphisms in Behçet's disease

OBJECTIVE

Contribution of HLA-B51 to the genetic susceptibility for Behçet's disease is well documented and recent studies suggest involvement of other genes. Tumour necrosis factor (TNF) genes are located in the vicinity of the HLA-B locus. Polymorphisms in the promoter region of TNF-alpha gene has been found to be associated with altered TNF secretion, and it may have a prominent role in the increased inflammatory responses of Behçet's disease.

METHODS

The study group consisted of 99 Behçet's disease patients and 96 healthy matched controls. All patients fulfilled the International Study Group criteria for Behçet's disease. The TNF-alpha -308 and -376 promoter alleles were assigned by the digestion of each amplified PCR product with NcoI and TasI enzymes, respectively.

RESULTS

No significant difference was observed in the distribution of TNF-alpha promoter region polymorphisms between patients with Behçet's disease and controls. There was no association between the presence of uncommon -308A and -376A alleles and the manifestations or severity of Behçet's disease either. The TNF-alpha -308A allele and HLA-B*50 was found to be associated in this series of Turkish patients and controls.

CONCLUSION

The role of TNF-alpha promoter region -308 and -376 polymorphisms in the pathogenesis of Behçet's disease is not supported by this data. The overexpression of TNF-alpha in Behçet's disease may be caused by other polymorphisms in the TNF gene or by post-transcriptional mechanisms.

Anti-endothelial cell antibodies in Behçet's disease

OBJECTIVE

Circulating antibodies that bind to human endothelial cells cultured in vitro have been detected in a variety of diseases, including Behçet's disease. In this disorder the reported prevalence of AECA has varied widely. One likely source of variability is the ELISA assay itself, in which differing conditions and reagents have been used in different reports.

METHODS

We have re-examined the frequency of AECA in 132 Turkish Behçet's patients and 50 healthy Turkish controls, comparing several different methods of preparing the target endothelial cells. Human umbilical vein endothelial cells (HUVEC) were used either: 1) fresh and non-treated, 2) fixed, or 3) TNF alpha-stimulated. All stages of the procedures were performed at room temperature.

RESULTS

In Behçet's patients, using fresh, non-treated HUVEC, 17 of 130 (13.1%) and 9 of 132 (6.8%) sera were positive for IgG- and IgM-AECA, respectively. However, among 50 normal controls, 2 (4.0%) had IgG-positive and 4 (8.0%) had IgM-positive ELISAs under the same conditions. The difference in the frequency of positives between patients and controls was not statistically significant. Fixed HUVEC and TNF alpha-treated HUVEC gave similar results as well. When group means were examined, only the mean for IgG-AECA determined with TNF alpha-stimulated HUVEC reached statistical significance.

CONCLUSION

The discrepancy between our data and earlier reports in the literature probably reflects the methodological differences alluded to, and highlights the difficulties in interpreting ELISA assays for AECA.

Genetic affinities among Mongol ethnic groups and their relationship to Turks

The central Asian country Mongolia is home to more than 20 tribes and ethnic groups, some of which are related to neighboring Turkic populations. The main Mongolian people, Khalkha, live in central and eastern Mongolia while the Tsaatan minority lives in the north of the country. The Oold minority is from the western Altai mountain region and live in close proximity with Turkic people. We have typed the HLA-A, -B, -Cw, -DRB1 and -DQB1 loci by PCR-SSP in these three Mongolian populations as well as a sample of the German population. To examine their genetic relationships, a sample of the Turkish population already typed at the HLA-A, -B and -DRB1 loci were used. Altogether five populations were analyzed: Khalkha (n = 100), Tsaatan (n = 72), Oold (n = 52), German (n = 260) and (Anatolian) Turkish (n = 498). Nei's unbiased genetic identity (GI) and genetic distance (GD) were estimated from genotypes using PopGene v1.31, and dendrograms were constructed using phylip. The results suggested a close relationship of the Khalkha to the Tsaatan. The Turks and Germans were equally distant to all three Mongolian populations. These results confirmed the lack of strong genetic relationship between the Mongols and the Turks despite the close relationship of their languages (Altaic group) and shared historical neighborhood. This study has provided useful population data for genetic and anthropologic studies bridging eastern and western populations.

A weak association of HLA-B*2702 with Behçet's disease

This study aimed to analyse the association of HLA-B alleles other than -B51 with Behçet's disease (BD). We also investigated the frequency of HLA-B alleles sharing the same natural killer cell immunoglobulin-like receptor (KIR) binding sequence with HLA-B51. Broad-genotyping of HLA-B locus by PCR-SSOP in 174 Turkish BD patients and 191 healthy controls confirmed the strong association of B*51 with BD (60.9% in BD patients, 24.6% in healthy controls, OR = 4.78). No other HLA-B allele was identified showing an association with BD after adjusting for multiple testing or by using relative predispositional effects (RPE) analysis after the deletion of B*51. HLA-B alleles reacting with the sequence specific oligonucleotide probe 23, which corresponds to the KIR binding site of B*51, were found to be positive in 127 BD patients (73%) and 90 controls (47%) (OR = 3.03, 95% CI 2-4.7). The repeated RPE analysis after separating HLA-B alleles carrying B51-KIR binding sequence as distinct alleles within a broad-type allele group revealed B*2702 allele as the only allele showing an association with BD after the deletion of B*51. Selective increase of B*2702, the only B*27 allele carrying the same KIR binding sequence with B*51, warrants investigation of the possibility of interaction of HLA molecules with KIRs on NK or other T cells in the pathogenesis of BD.

Autoreactivity to myelin antigens related to HLA associations with multiple sclerosis

Multiple sclerosis (MS) is considered as an immune process influenced by genetic and environmental factors. HLA-DR2 and -DR4 have been documented to be associated with MS. The HLA-dependent differences of immune response to myelin and other antigens might point out some relevant mechanisms in MS development The responses to myelin antigens and to PPD have been compared in 21 MS patients and 25 healthy controls (HCs) by primary proliferation and by short-term T-cell lines. There was a significantly higher response to MBP in DR2+ HCs compared to MS patients (SI: 5.9 versus 1.5, p = 0.02). In short-term T-cell lines, we observed a higher response to PLP30-49 in both DR4+ HCs and MS patients This response was significantly more frequent in DR4+ MS patients (34.6%) than both DR2+ MS patients (0%, p = 0.0001) and DR4+ HCs (7.7%, p = 0.001). The comparison between DR2+ and DR4+ MS patients has revealed that the response to MBP was also increased in DR4+ (p = 0.02). Among DR4+ groups, an increased PPD response was detected in HCs compared to MS (65.2% versus 33.3%, p = 0.01). These results may indicate that HLA-related differences to specific and recall antigens are detectable in MS and these differences may have implications in the disease pathogenesis.

Human HSP 60 peptide responsive T cell lines are similarly present in both Behçet's disease patients and healthy controls

Heat shock protein (HSP, 60/65 kDa) is investigated as a candidate autoantigen in Behçet's disease (BD), a systemic vasculitis of unknown origin, and a prominent response to 'disease-specific epitopes' of mycobacterial and human HSP60/65 is described in BD patients. In this study, long-term T cell lines from peripheral blood of BD patients (n=6) and controls (n=7) were stimulated with mycobacterial recombinant HSP and purified protein derivate (PPD) and expanded with IL-2. In the BD group, 15 out 27 and in the controls, 25 out of 35 PPD specific T cell lines have responded to the synthetic peptides of the human HSP60. Out of the primarily HSP-specific T cell lines, 17/23 in patients and 8/8 in controls did recognize a peptide of human origin. T cell lines specifically reactive to 136-150, 179-197, 244-258 and 336-351 could be raised with similar frequency in both groups. In contrast to a previous report, T cells also reacted to peptide 425-441 frequently in both groups. The results demonstrate that the human proliferative response to mycobacterial HSP may also target the self-protein in both BD patients and controls. However, the responsive T cells may have different effects depending on their functional features such as cytokine secretions.

Lack of association of HLA-B*51 with a severe disease course in Behçet's disease

OBJECTIVE

To investigate the previously reported association of HLA-B51 with the manifestations and severity of Behçet's disease (BD).

METHODS

The study group consisted of 148 consecutive BD patients (89 male, 59 female) with a minimum disease duration of 5 yr followed up at an out-patient BD clinic in a tertiary referral centre. The patients were classified into three severity groups (mild, moderate, severe) using a modified form of the BD total activity index. HLA-B alleles were determined by DNA amplification using the polymerase chain reaction and sequential hybridization with sequence-specific oligonucleotide probes.

RESULTS

The frequencies of genital ulceration [odds ratio (OR)=3.1, 95% confidence interval (CI) 1.3-7.5], skin findings (erythema nodosum, folliculitis or acne-like lesions) (OR=4.4, 95% CI 1.1-17.7), a positive skin pathergy test (OR=3.4, 95% CI 1.1-10.9) and eye disease (OR=1.8, 95% CI 0.9-3.7) were all higher in B*51-positive patients. By contrast, no significant association was observed between B*51 positivity and a severe disease course, and B*51 homozygosity did not exhibit a prominent association with the severity of BD. Male sex was found to be the strongest determinant of the severity of BD by logistic regression analysis (OR=4.7, 95% CI 1.9-11.2).

CONCLUSION

HLA-B*51 does not exhibit a strong association with a more severe disease course in BD. The involvement of other genetic and/or environmental factors seems to be required and to be more important than B*51 for the progression of BD.

Anti-alpha B-crystallin immunoreactivity in inflammatory nervous system diseases

alpha B-Crystallin, a small heat shock protein, is an immunodominant antigen with increased tissue expression in demyelination. To investigate the humoral response against alpha B-crystallin, the sera and CSF samples of patients with multiple sclerosis (MS), Guillain-Barré syndrome (GBS), neuro-Behçet's disease (NBD) and other non-inflammatory neurological diseases (NIND) were screened by enzyme-linked immunosorbent assay for anti-alpha B-crystallin IgG and IgM antibodies. Serum and CSF IgG antibody responses to alpha B-crystallin were significantly elevated only in NBD patients (serum IgG, NBD 1.29 +/- 0.49 vs. NIND 0.95 +/- 0.39, P = 0.01; CSF IgG, NBD 1.22 +/- 0.64 vs. NIND 0.81 +/- 0.35, P = 0.01). Similarly, high serum IgM antibody titres were also detected in NBD (1.83 +/- 0.72 vs. 1.16 +/- 0.49, P = 0.0005) and in MS (1.57 +/- 1.07, P = 0.046), whereas elevated CSF IgM responses were observed only in GBS (2.09 +/- 1.09 vs. 1.41 +/- 0.7, P = 0.007). Humoral responses against alpha B-crystallin are increased in NBD and GBS, which may implicate this central nervous system antigen in the causation and pathogenesis of these inflammatory nervous system disorders.

HLA-DR and -DQ associations with insulin-dependent diabetes mellitus in a population of Turkey

Genetic susceptibility to insulin-dependent diabetes mellitus (IDDM) has been shown to be associated with MHC in many studies. To extend this data with a population with relatively low IDDM incidence, MHC DRB, DQA, and DQB have been investigated by polymerase chain reaction and sequence specific oligonucleotide probe hybridization (PCR/SSO) in 178 IDDM patients from Turkey and compared to 248 healthy controls. Significant differences are detected between IDDM and control groups in the frequencies of DRB1*0402 DQA1*03 DQB1*0302 (28.1% vs. 5.2%, p < 0.0001, OR: 7.1) and DRB1*0301 DQA1*0501 DQB1*02 (57% vs. 18.1%, p < 0.0001, OR: 6.1). Among the negative associations, the most strong ones are with DRB1*1401 DQA1*0101 DQB1*0503 (0.6% vs. 8.9%, p < 0.0001, OR: 0.1), DRB1*1502 DQA1*0103 DQB1*0601 (1.1% vs. 7.7%, p = 0.0023, OR: 0.1), DRB1*1301 DQA1*0103 DQB1*0603 (0.6% vs. 6.9%, p = 0.0039, OR: 0.2) and DRB1*1101 DQA1*0501 DQB1*0301 (3.9% vs. 12.1%, p < 0.0001, OR: 0.2). When the DRB, DQA or DQB genotypes of the susceptible alleles are compared, the most strong susceptibility marker of the disease is found to be DRB1*0301/*04 (31.4% vs. 2.8%, p < 0.0001, OR: 15.8) and among these, heterozygote genotype DRB1*0301/*0401 (4.5% vs. 0, p = 0.0008, OR: 24.8). These results confirm the positive associations with IDDM previously observed in other Caucasian populations and reveal many negative and strong associations which maybe underlining several characteristics that distinguish Turkish diabetics form other Caucasians.