HLA and Kaposi''s sarcoma in Sardinia

Twelve Sardinian patients affected by histologically defined classic Kaposi's sarcoma (KS) were HLA-A, B, C and DR typed. Compared to 220 age and ethnically matched healthy controls, KS patients showed a significant increase in HLA-DR5 (66.6 vs 23.1%, P less than 0.001) and a considerable decrease in HLA-DR3 (8.3 vs 53.6%, P = 0.0055). No definite association was observed for other HLA antigens. These results confirm the existence of an HLA associated genetic control of KS susceptibility and support the hypothesis that HLA-DR5 plays the role of a predisposition marker while HLA-DR3 bears a genetic resistance to the disease.     

HLA antigen distribution in different clinical subgroups demonstrates genetic heterogeneity in lichen planus

Summary HLA-A, B, Cw, DR and DQ antigens were serologically determined in 105 patients suffering from lichen planus (LP). Of these patients, 87 had idiopathic LP and 18 had secondary LP. In the first group, 43 had cutaneous LP without mucosal lesions, 17 had cutaneous LP with mucosal lesions and 27 had purely mucosal LP. No HLA antigen was found to be significantly associated with secondary LP or with mucosal idiopathic LP. In cutaneous idiopathic LP with or without mucosal lesions, the HLA-DR1 and DQ1 antigen frequency was significantly increased, and that of HLA-DQ3 significantly decreased. Among the HLA-DR1 cutaneous idiopathic LP patients, 78.5% carried the DRB1*0101 allele, and 214% the DRBI*0102 allele, compared with 35.7 and 67.8%, respectively, of the HLA-DR1 controls. Our data demonstrate that idiopathic LP is influenced by HLA-associated genetic susceptibility and resistance factors not involved in secondary LP, and that cutaneous idiopathic LP is a genetically and therefore pathogenetically different condition from purely mucosal idiopathic LP.     

Endemic HBV infection, tissue autoantibodies and HLA: Analysis of a Sardinian population

Serum samples of 405 HLA-typed individuals from four Sardinian villages were analyzed for HB virus markers and for tissue autoantibodies. Of the 59% individuals who had been exposed to HBV, 10% were healthy carriers; they showed a weak association with the HLA-B40 specificity compared with the immune or non-exposed groups, and a negative association of DR4, limited to females. Tissue autoantibodies were significantly associated with DR1 and more weakly with B14, probably through linkage disequilibrium.     

The relative importance of the X-linked FCP locus and β-globin haplotypes in determining haemoglobin F levels: a study of SS patients homozygous for βS haplotypes

Five factors have been hypothesized to influence the 20-fold variation in fetal haemoglobin (Hb F) levels in sickle cell anaemia (SS): age sex, α-globin gene number, β-globin haplotype, and the X-linked F-cell production locus (FCP) that regulates the production of Hb F containing erythrocytes (F cells). We analysed the association of these factors with Hb F levels in 112 SS patients living in France who are homozygous for the three common African β-globin haplotypes (Benin, Bantu or Central African Republic and Senegal). We found that: (1) FCP accounts for about 40% of the overall variation in Hb F levels, (2) when the FCP influence is removed, β-globin haplotype is associated with 14% of the remaining Hb F variation, and (3) the other factors have little influence. Comparison with our previous study of SS individuals in Jamaica leads to the following conclusions: (1) the X-linked FCP locus is a major determinant of Hb F levels in SS disease, (2) factors linked to the β-globin haplotype have only a small effect on the variation in Hb F levels, in either the homozygous or heterozygous state, and (3) approximately half of the variation in Hb F levels still remains to be explained.