Biological autoimmunity screening in hepatitis C patients by anti-HepG2 lysate and anti-heat shock protein 70.1 autoantibodies.

Viruses require viral and cellular chaperones during their life cycle and interactions of these molecules with the immune system are probable during the infection. Thus, an anti-chaperone antibody response has been firstly investigated in hepatitis C patients in this paper. A HepG2-lysate antigen (90, 79, 72, 70, 62, 54 and 48 kDa) was assayed in sera from 59 (19F/40M) chronic hepatitis C patients without cirrhosis before therapy. Forty of them were positive for anti-HepG2 lysate antigen antibodies and this test may evaluate biological autoimmunity. Hsp70.1, Hsp90 and calreticulin levels were significantly higher in this antigen than in a control HepG2 antigen. Secondly, Hsp70.1 was identified as Hsp 70 kDa protein-1 by proteomic analysis and studied as a possible antibody target. Fourteen out of 59 patients were positive for anti-Hsp70.1 antibodies that were inversely correlated with alanine aminotransferase levels, the Metavir activity index and viraemia. Finally, for comparative purposes, 50 sera from systemic lupus erythematosus (SLE) patients have been tested: eight and 41 of them were positive for anti-Hsp70.1 and anti-HepG2 lysate antigen antibodies, respectively. Therefore, anti-Hsp70.1 autoantibodies may be produced and can partially lead to biological autoimmunity in chronic hepatitis C patients.