Do specific pockets of HLA-C molecules predispose Jewish patients to psoriasis vulgaris?

BACKGROUND: Psoriasis vulgaris was reported to be associated with a specific alanine residue at position 73 of HLA-C alleles in Japanese patients. OBJECTIVE: Our purpose was to determine the role of HLA genes in susceptibility to psoriasis vulgaris in the Israeli Jewish population. METHODS: Twenty-eight Israeli patients were analyzed for their HLA class I and II specificities by means of serologic and molecular methods. RESULTS: All patients possessed in their HLA-C antigens an alanine residue at position 73 (p < 0.002). A significantly increased frequency of HLA-Cw6 and of Cw7 was also observed among the patients (p < 0.02). CONCLUSION: Our study clearly shows that alanine in position 73 is significantly associated with psoriasis vulgaris in Jewish patients. Cw6 and Cw7 have a unique antigen-binding pocket containing both alanine at position 73 and a negatively charged aspartic acid at position 9. These residues are most probably important in determining the conformation of the C pocket and in turn the nature of the peptide bound to it. We suggest that this combination confers the highest risk of the development of psoriasis vulgaris.

Erythroderma and pneumonitis induced by penicillin?

Penicillin and its derivatives are known to cause several dermatologic and pulmonary hypersensitivity reactions. This report describes a patient who presented with combined generalized exfoliative dermatitis and severe pneumonitis caused by penicillin and aggravated by ampicillin, methicillin and mezlocillin. Antibiotic challenges with penicillin caused immediate reappearance of the dermatological manifestation; reactivation of the pneumonitis was probably prevented by immediate discontinuation of the drug.