Resolution of HLA-B*44:02:01G, -DRB1*14:01:01G and -DQB1*03:01:01G reveals a high allelic variability among 12 European populations.

Within the framework of the EU-funded HLA-NET action, an analysis of three G-group alleles, HLA-B*44:02:01G, DRB1*14:01:01G and DQB1*03:01:01G, was undertaken in 12 European populations. Ambiguities were resolved by polymerase chain reaction-sequence-specific amplification (PCR-SSP) or PCR-sequence-based typing (PCR-SBT) in a total of 5095 individuals. The results of the DRB1*14:01/14:54 ambiguity showed high relative ratios (24-53%) of DRB1*14:01 in Bulgarians, Croatians, Greeks, Italians and Slovenians, contrasting with low ratios (6-13%) in Austrians, Finnish, French, Hungarians, Norwegians and Swiss. Resolution of the B*44:02/44:27 ambiguity showed that B*44:27 had a high relative ratio in Slovenians (25.5%) and Bulgarians (37%) and low in French and Swiss (0.02-1%), and was not observed in Greeks and Italians. The highest relative ratio of DQB1*03:19 was found in Portuguese (11%), by contrast with low ratios (0-3%) in the other five populations. Analysis of the A, B, DRB1 phenotypes and family-derived haplotypes in 1719 and 403 individuals positive for either HLA-B*44:02G or DRB1*14:01G ambiguities, respectively, showed some preferential associations, such as A*26∼DRB1*14:01, B*35∼DRB1*14:01, B*38∼DRB1*14:01 and B*44:27∼DRB1*16. Because these ambiguities are located outside the peptide-binding site, they may not be recognized by alloreactive T-cells. However, because of strong linkage disequilibrium (LD), the DRB1*14:01 vs DRB1*14:54 and the B*44:02 vs B*44:27 mismatches are associated to DRB3-, and C-mismatches, respectively. These results are informative for algorithms searching unrelated hematopoietic stem cell donors. For B*44:27-positive patients, searches are expected to be more successful when requesting donors from Southeastern-European ancestry. Furthermore, the introduction of human leukocyte antigen (HLA)-typing strategies that allow resolving exon 4 (for class I) and exon 3 (for class II) polymorphisms can be expected to contribute significantly to population genetics studies.

Analysis of the HLA population data (AHPD) submitted to the 15th International Histocompatibility/Immunogenetics Workshop by using the Gene[rate] computer tools accommodating ambiguous data (AHPD project report).

During the 15th International Histocompatibility and Immunogenetics Workshop (IHIWS), 14 human leukocyte antigen (HLA) laboratories participated in the Analysis of HLA Population Data (AHPD) project where 18 new population samples were analyzed statistically and compared with data available from previous workshops. To that aim, an original methodology was developed and used (i) to estimate frequencies by taking into account ambiguous genotypic data, (ii) to test for Hardy-Weinberg equilibrium (HWE) by using a nested likelihood ratio test involving a parameter accounting for HWE deviations, (iii) to test for selective neutrality by using a resampling algorithm, and (iv) to provide explicit graphical representations including allele frequencies and basic statistics for each series of data. A total of 66 data series (1-7 loci per population) were analyzed with this standard approach. Frequency estimates were compliant with HWE in all but one population of mixed stem cell donors. Neutrality testing confirmed the observation of heterozygote excess at all HLA loci, although a significant deviation was established in only a few cases. Population comparisons showed that HLA genetic patterns were mostly shaped by geographic and/or linguistic differentiations in Africa and Europe, but not in America where both genetic drift in isolated populations and gene flow in admixed populations led to a more complex genetic structure. Overall, a fruitful collaboration between HLA typing laboratories and population geneticists allowed finding useful solutions to the problem of estimating gene frequencies and testing basic population diversity statistics on highly complex HLA data (high numbers of alleles and ambiguities), with promising applications in either anthropological, epidemiological, or transplantation studies.

Visfatin, TNF-alpha and IL-6 mRNA expression is increased in mononuclear cells from type 2 diabetic women.

Visfatin, is a new adipokine, highly expressed in the visceral fat of both mice and humans. To examine whether visfatin is expressed in human peripheral monocyte-enriched mononuclear cells and whether its expression is altered in type 2 diabetes (DM2), we compared 24 DM2 women [17 overweight (BMI >25) and 7 lean (BMI<25)] to 26 healthy women (14 overweight and 12 lean), all premenopausal. Relative visfatin mRNA levels were significantly higher (approximately 3-fold) in DM2 compared to healthy control women (p<0.02), independently of the presence of overweight/obesity. Mononuclear TNF-alpha and IL-6 mRNA expression was also elevated in DM2 compared to control women (p=0.001 and p=0.004, respectively), an increase observed in both lean and overweight DM2 women. By contrast, circulating visfatin, TNF-alpha, and IL-6 levels showed no difference between DM2 and control women, while adiponectin plasma levels were significantly decreased in the DM2 women (p<0.001). Circulating visfatin and TNF-alpha levels did not differ either between the lean and the overweight subgroups of DM2 and control women, while IL-6 plasma levels were significantly higher in both overweight subgroups compared to their lean counterparts. In conclusion, visfatin, TNF-alpha, and IL-6 mRNA expressions are increased in peripheral mononuclear-monocytic cells from women with type 2 diabetes, independent of their BMI, which may enhance the effects of their adipose-derived levels and may contribute to the increased insulin resistance and atherogenic risk of these patients.

Human leukocyte antigens as genetic markers in Greek patients with sporadic pancreatic cancer.

PURPOSE: In this study we investigated the relationship between specific HLA antigens and sporadic pancreatic cancer in Greek population. METHODS: The allele frequencies of serologically and molecular defined class I and II HLA antigens were studied in 60 unrelated patients with pancreatic cancer histologically confirmed. The results obtained for HLA frequencies were compared with those of 105 healthy control subjects (control group). RESULTS: Increased frequencies of HLA-A30 (16.7 vs. 3.8%; P < 0.01; OR = 5.05), A31 (9.5 vs. 1.9%; P < 0.05; OR = 5.72), B18 (31.7 vs. 14.3%; P < 0.05; OR = 2.78) and Cw7 (53.3 vs. 21.9%; P < 0.01; OR = 4.07) were observed in patients with pancreatic cancer in comparison to the control subjects. CONCLUSIONS: This study demonstrates the association between specific HLA antigens and pancreatic cancer development in whites and suggests a genetic susceptibility factor for the disease.

Human leukocyte antigens as genetic markers in colorectal carcinoma.

PURPOSE: Similar to findings obtained for most carcinomas, the pathogenesis of colorectal cancer is considered to be multifactorial. There is strong evidence for an inherited, genetic predisposition to disease in patients with familial adenomatous polyposis and hereditary nonpolyposis colorectal cancer. There is still debate, however, about the contribution of genetic factors to the pathogenesis of sporadic colorectal cancer. The present study was undertaken to search for human leukocyte antigen associations in a group of patients with colorectal cancer and to correlate the findings with both the histology of the disease and family history. SUBJECTS AND METHODS: The allele frequencies of serologically defined human leukocyte antigen class I and II antigens were studied in 101 patients with a recent, histologically confirmed diagnosis of colorectal cancer. All individuals in this study were unrelated to each other. After surgical treatment, all patients were grouped according to the stage (Dukes Stages A, B, C, and D), differentiation (Grades 1, 2, and 3), and the site of the tumor. Patients were also classified with regard to family history for colorectal cancer. The results obtained for human leukocyte antigen frequencies were compared with those of 105 healthy control subjects (control group). RESULTS: An increased frequency of human leukocyte antigen-B18 (27.72 vs. 14.28 percent; P < 0.025; odds ratio = 2.3) and of human leukocyte antigen-DQ5 (43.56 vs. 22.5 percent; P < 0.01; odds ratio = 2.65) was observed for patients with colorectal cancer vs. control subjects, respectively. In addition, human leukocyte antigen-B18 was present with increased frequency (30.76 percent; P < 0.05; odds ratio = 2.66; and 26.67 percent; P < 0.05; odds ratio = 2.18) among patients with rectal and colon carcinoma, respectively. A higher frequency of human leukocyte antigen-DQ5 (45.33 percent; P < 0.01; odds ratio = 2.84) was observed among patients with colon carcinoma. Remarkably, human leukocyte antigen-DQ5 (50 vs. 22.5 percent; P < 0.05; odds ratio = 3.43) and human leukocyte antigen-A1 (41.66 vs. 12.38 percent; P < 0.01; odds ratio = 5.05) were found to be strongly associated with a family history of colorectal cancer. CONCLUSION: The observation of specific human leukocyte antigen associations with particular subsets of colorectal cancer strongly suggests that genetic susceptibility for the development of colorectal cancer exists. Although the multifactorial pathogenesis of colorectal cancer must be considered, human leukocyte antigens may have useful predictive and diagnostic value.

HLA-TNF haplotype heterogeneity in Greek SLE patients.

OBJECTIVE: To examine TNF microsatellite allele frequencies in SLE patients in the Greek population, where disease susceptibility is less associated with HLA-DR3 haplotypes. METHODS: A cohort of 46 Greek SLE patients were investigated. Allele frequencies for the TNF microsatellite markers a, b, c and d were determined using a fluorescence based DNA fragment sizing technique. HLA class II typing was performed using a molecular based technique. RESULTS: Associations between SLE and DRB1*1501, *1601 and *0701 were observed and DRB1*0301 was only marginally increased in patients. Linkage disequilibrium was found between DRB1*1501 and TNF a11 and also for DR3 and TNF a2, b3, d2. Stratification of patients suggested that DRB*1501 and TNF a11 frequencies were higher in SLE patients with renal disease and TNF a2 and b 3 frequencies in those without, although these differences did not reach statistical significance. CONCLUSIONS: SLE in this Greek population appears to be associated with a number of HLA-DRB1 alleles. The development of renal complications in these patients may be related to the TNF polymorphism encoded on these HLA haplotypes.

Necrotizing vasculitis in Greece: clinical, immunological and immunogenetic aspects. A study of 66 patients.

The clinical spectrum and outcome of necrotizing vasculitis were evaluated in a retrospective study in order to assess: (1) the clinical expression and evolution of the disease; (2) the response to several therapeutic approaches based on major events (organ involvement causing disability or death); (3) the immunogenetic background of patients. Sixty-six Greek patients fulfilling the ACR criteria for the diagnosis of vasculitis entered the study. Thirty-seven were diagnosed with Wegener's granulomatosis (WG), 22 with polyarteritis nodosa (PAN) and seven with Churg-Strauss syndrome (CSS). The demographic characteristics of patients with WG and PAN were similar. Cutaneous manifestations, gastrointestinal and peripheral nervous system involvement occurred more often in patients with PAN, whereas pulmonary and upper respiratory tract involvement, renal, ear abnormalities and fever were more frequent in patients with WG. Muscle weakness and asthma were found exclusively in patients with PAN and CSS, respectively, while the presence of classic-antineutrophil cytoplasmic antibodies (c-ANCA) characterized WG patients. Hepatitis B surface antigen (HBsAg) was found in 22% of PAN patients. No significant differences were detected when comparing the PAN and WG groups with respect to the first major event (log-rank P = 0.50) with and without potential confounders (age, gender, therapy or c-ANCA). For WG patients, a statistically significant difference was found on different routes of administration of cyclophosphamide (oral vs pulse) (P = 0.006). Regarding the HLA antigens, an increased frequency of DR1 (26.9% vs 10.3%, P = 0.057) in WG and the absence of DR3 in patients with PAN and CSS were noted. It appears that although the immunogenetic background and the clinical expression of the diseases differ, the response to treatment as well as the evolution and the survival rate of these patients are similar in the two groups.

HLA in familial and nonfamilial Mediterranean Kaposi's sarcoma in Greece.

Fifty-four (54) unrelated patients with Mediterranean Kaposi's sarcoma (MKS) and 8 patients members of 4 unrelated families with familial MKS were serotyped for HLA-A,B and DR antigens. The diagnosis was histologically confirmed and all patients were negative for anti-HIV antibodies. An increased frequency of HLA-B18 (44.4% vs 14.2% in the controls, p < 0.001, RR = 4.8) and HLA-DR5 (57.6% vs 37.2% in the controls, p < 0.025, RR = 2.29) was observed in the group of patients with MKS. Seven (7) of the 8 family members with FMKS possessed HLA-DR5, and the affected members in the 3 families shared a common haplotype which included HLA-DR5. These findings support the hypothesis that genetic factors linked to HLA-DR5 antigen may contribute to the pathogenesis of MKS.

D-penicillamine induced myasthenia gravis in rheumatoid arthritis: an unpredictable common occurrence?

Five patients out of 71 with rheumatoid arthritis (RA), who received D-penicillamine, developed myasthenia gravis (MG) within a two-year period. They all responded promptly to discontinuation of the drug and pyridostigmine administration. None of the patients had anti-Ro(SSA) antibodies or features of Sjögren's syndrome, whereas three of the five had the HLA-DR1 phenotype. The relatively high frequency of MG observed in our population, along with its unpredictability and potentially serious sequelae, necessitates its inclusion in the list of side effects of D-penicillamine routinely discussed with the patient, prior to initiation of the treatment. Full alertness of both the patient and the physician to even minor initial myasthenic symptoms, that dictate immediate discontinuation of the drug, is of obvious importance.

HLA alloantigens in Greek patients with systemic lupus erythematosus.

The frequency of the HLA-A, -B and -DR alloantigens was studied in 74 unselected, consecutive, unrelated Greek patients with systemic lupus erythematosus (SLE) and the results were compared with those of healthy controls (380 for the class I antigens and 154 for the class II antigens). No statistically significant differences were noted between patients and controls regarding the prevalence of any class II antigen. Furthermore, no such differences were observed between our 36 anti-Ro (SSA) positive and the rest of our SLE patients. However, the coexistence of anti-Ro (SSA) and anti-La (SSB) antibodies (9 patients) correlated significantly with HLA-B8, whereas the haplotype HLA-B8DR3 was more common in the anti-Ro (SSA) positive patients than in the rest-although the difference did not reach statistical significance. The combination of high anti-ds-DNA and low C4 serum levels correlated with absence of HLA-DR5. Our findings, while in agreement with those of certain previous studies, are somewhat different from those of others. The differences may at least partly be related to variations in the control populations employed. On the other hand some of the differences, in accordance with other peculiarities of Greeks with connective tissue disease, emphasize the role of racial and/or ethnic background in the HLA-association of various autoimmune diseases and the fact that the detectable HLA alloantigens in certain diseases modify disease and autoantibody expression rather than being responsible for the autoimmune process itself.

High frequency of HLA-DR5 in Greek patients with haemophilia A and haemophilia B.

Sixty unrelated Greek patients with haemophilia (46 with haemophilia A and 14 with haemophilia B) were typed for HLA-A, B and DR antigens. A highly significant increase in the frequency of HLA-DR5 was observed in both groups of patients (58.6% vs 30.0%, chi 2 = 10.47, pc less than 0.03, RR = 3.31 for haemophilia A and 78.5% vs 30.0%, chi 2 = 12.32, pc less than 0.007, RR = 8.5 for haemophilia B). An increased frequency of HLA-B13 was also observed in patients with haemophilia A (15.2% vs 5.7%, chi 2 = 5.74, pc less than 0.4, RR = 2.9). Thirty of the 60 patients (50.0%) were positive for LAV/HTLVIII antibodies. HLA-DR5 was equally distributed in patients with and without these antibodies (63.3% and 63.3%, respectively). The presence of DR5 did not correlate with the severity of haemophilia A or B. These results may suggest an influence of gene(s) on chromosome 6 in haemophilia A and haemophilia B and no effect of HLA antigens in the susceptibility to LAV/ HTLVIII infection among haemophiliac patients.

HLA-A,-B, and -DR antigens in relation to gold and D-penicillamine toxicity in Greek patients with RA.

Ninety-five rheumatoid arthritis patients treated with aurothiomalate and/or D-penicillamine have been studied for possible associations between HLA-A, -B, -DR antigens and various toxic reactions to the above drugs. HLA-DR3 and -DRw6 had a higher frequency in patients with toxic reactions (all types) than in patients without toxic reactions (28.5 per cent vs 13.0 per cent and 26.5 per cent vs 4.3 per cent, chi 2 = 2.6 and 7.2, respectively). HLA-B8 was found at a higher frequency in patients with proteinuria and other types of renal involvement (20.0 per cent vs 7.4 per cent in controls), whereas skin manifestations were mainly associated with the presence of HLA-DRw6. The lowest frequency of side-effects was seen in patients with HLA-DR1 and DR2 (10.2 per cent vs 28.3 per cent and 28.5 per cent vs 54.3 per cent, chi 2 = 3.9 and 5.5, respectively). In addition, seropositive patients possessing HLA-DR1, showed toxic reactions less frequently.

Histocompatibility antigens HLA-A, -B, -DR in Greek patients with Kaposi's sarcoma.

Thirty-two Greek patients with histologically documented Kaposi's sarcoma, aged 46 to 82 years, were typed for HLA-A, B and DR antigens. None of them was homosexual and they had not been subjected to any immunosuppressive therapy. The study revealed a significant increase of HLA-DR5 (53.1% vs. 21.4%, R.R. 4.1) and a decreased frequency of HLA-DR1 (3.3% vs. 16.6%, R.R. 0.16). An increased frequency of HLA-B18 was also noted (43.7% vs. 20.7% R.R. 2.96). These results indicate that the same positive association with HLA-DR5 antigen is observed in Greek patients as in other patients of Mediterranean origin and support the view that HLA linked factor(s) may have a role in the development of the disease.