[IgG autoantibodies against cellular p72 antigen crossing with (MLV) p15-gag antigen: presence in early HIV 1 infection, in HBV infection and in primary Gougerot-Sjögren].

IgG antibodies of autoimmune SLE (Systemic Lupus Erythematosus) serum S detected a HeLa hnRNP 72 kDa protein, cross-reacting with the retroviral (MLV) p15-gag polypeptide. Since serum S disclosed a ubiquitous 72 kDa antigen in HeLa cell fractions, was prepared the so-called cytoplasmic "X fraction", enriched for the 72 kDa protein, defined here as p72. This autoantigen was detected by antibodies of HIV 1+ patients, recently of seroconverted (RSC) asymptomatic subjects, of HBV+ sera, and of primary Gougerot-Sjögren (prGS) sera. The presence of these autoantibodies in different autoimmune and infectious pathologies raises the question of the involvement of p72 in the immune processes and in the early HIV1 infection.