Antibodies against LSP in the sera of 163 patients with various typesof viral hepatitis were determined with SPA-RIA.The sera of anothergroup of 118 patients(109 of them were from the first group)withviral hepatitis were studied with ELISA for the same antibodies,whichwere further divided into three categories,that is,IgG,IgM,and IgAclasses.The results of 109 patients examined with both of the two me-thods indicated that anti-LSP antibodies measured by SPA-RIA mightmainly represent anti-LSP IgG class.It was found that circulating anti-LSP antibodies could easily be detected in most patients with either acuteor chronic hepatitis.After analyzing the results,the authors suggest thatthe humoral immune response against LSP might not be the sole initiatingfactor in the pathogenesis of viral hepatitis,they are more likely theresult of the antigen variation of the injured liver cells. Antibodies against LSP in the sera of 163 patients with various types of viral hepatitis were determined with SPA-RIA. The sera of another group of 118 patients (109 of them were from the first group) with viral hepatitis were studied with ELISA for the same antibodies, whichwere further divided into three categories, that is, IgG, IgM, and IgAclasses.The results of 109 patients examined with both of the two me-thods indicated that anti-LSP antibodies measured by SPA-RIA mightmainly represent anti-LSP IgG class.It was found that circulating anti-LSP antibodies could easily be detected in most patients with either acuteor chronic hepatitis. After analyzing the results, the authors suggest that the humoral immune response against LSP might not be the only initiating factor in the pathogenesis of viral hepatitis, they are more likely theresult of the antigen variation of the injured liver cells.