These data suggest that the proinflammatory environment of streptococcal tonsillopharyngitis may enable B cells to activate autoreactive CD8+ T cells that, owing to the polyspecificity of T-cell receptors, recognize several B-cell self-peptides presented by HLA-C*06:02 and subsequently cross-react against melanocytes in the skin, thereby triggering psoriasis. The gene discussed is HLA-C; the disease is psoriasis.