Pemphigus refers to a group of autoimmune blistering skin diseases, mainly identified as pemphigus vulgaris and pemphigus foliaceus, both characterized by the presence of autoantibodies against keratinocyte adhesion molecules, leading to loss of cell-cell adhesion with consequent blister formation. Pemphigus vulgaris is reported to be associated with human leukocyte antigen DR4 and/or DR6 whereas no data are available on pemphigus foliaceus, except for the endemic Brazilian form (fogo selvagem), which is reported to be associated with DR1 and DR4. We here report human leukocyte antigen molecular typing on a total of 87 patients, 61 with pemphigus vulgaris and 26 with pemphigus foliaceus, versus 128 healthy matched controls. Generic typing showed an increase of DRB1*04 and DRB1*14 and a decrease of DRB1*07 in both pemphigus vulgaris and pemphigus foliaceus patients. Molecular subtyping of DR4+ and DR14+ subjects showed a highly significant association between the DRB1*1401 and both pemphigus vulgaris (p < 0.0001) and pemphigus foliaceus patients (p < 0.0001) together with a significant increase of the linked DQB1*0503 (pemphigus vulgaris p < 0.0001; pemphigus foliaceus p < 0.0001). Moreover, whereas the association between DRB1*0402 and pemphigus vulgaris (p < 0.0001) has been confirmed, no significant association between a specific allele of the DR4 group and pemphigus foliaceus, has been found. Therefore, at least in Italian patients, pemphigus vulgaris and pemphigus foliaceus share DRB1*1401 and DQB1*0503, as susceptible human leukocyte antigen alleles, whereas DRB1*0402 is only found associated with pemphigus vulgaris. The observation that both diseases, pemphigus vulgaris and pemphigus foliaceus, carry the same susceptible human leukocyte antigen alleles has been interpreted as a common genetic background predisposing to pemphigus as, like in other autoimmune disorders, it is not sufficient to explain the onset of the disease on the basis of the sole aforementioned alleles. Other linked genes and/or environmental factors should play a facilitating role in the outbreak of pemphigus, either pemphigus vulgaris or pemphigus foliaceus.

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Several studies have reported association between a variety of malignancies and human leukocyte antigens (HLA) genes. However, conflicting data have been reported on HLA association and melanoma. We report here serologic and molecular analysis by polymerase chain reaction sequence-specific primers (PCR-SSP) and PCR sequence-specific oligonucleotides (PCR-SSO) of HLA class I1 DRBl and DQB 1 loci in 132 patients with melanoma and 102 ethnically matched controls. Molecular typing of DQB 1 polymorphism showed a significant increase of DQB 1 *050 1 (25.0% versus 14.7%; p = 0.038). Moreover, an increase of DQB1*0301, which was present in 62.8% of patients and 54.9% of controls (p = 0.136), was noted. Because DQBl*O501 and DQB 1 *0301 are strongly linked to DRB 1 *O 1 and DRB 1 * 1 1, respectively, both found increased in patients with melanoma, to look for a more stringent association with a particular allele specificity of the DR locus, we performed PCR-SSP highresolution typing of DRl and DRI 1 positive subjects. Results showed no significant difference between the frequencies of the alleles found in patients with respect to controls. Analysis of the distribution of DQB 1 *0501 and DQB 1*0301 according to the AJCC clinical stage of the disease showed no significant difference in the frequency of these alleles between the localized and the metastatic form of the disease. However, none of the HLA class I1 alleles showed significant association after correction of the p value. These results indicate that HLA class I1 alleles may not contribute to a strong susceptibility to melanoma, at least in Italian patients.

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