[Reactivity of IgG class of anti-keratin autoantibodies in healthy human sera].

AIM: To analyze the reaction patterns of IgG class of anti-keratin autoantibodies (AK auto Abs) in normal human sera before and after purification, and to explore the effects of serum non-IgG components on the reaction patterns of IgG class of AK auto Abs. METHODS: Titers of IgG AK auto Abs in healthy human sera before and after purification were measured by indirect ELISA, and the reaction patterns of the AK auto Abs to a group of keratins with different relative molecule mass (M_r) were analysed by Western blot. RESULTS: Titers of purified IgG class of AK auto Abs were higher than those of unpurified sera. Western blot analysis showed purified AK auto Abs recognized more keratins with stronger avidity than unpurified AK auto Abs. The reaction patterns of AK auto Abs from different individuals tended to be homogenous after purification of AK auto Abs. CONCLUSION: The reaction patterns of serum IgG class of AK auto Abs are influenced by some non-IgG components in sera. The homogeneity of reaction patterns of AK auto Abs from different individuals indicated that B cells producing IgG class of AK auto Abs may be selected by a set of conserved self-antigens, and this process may have no relationship with an individual's exposure to foreign antigens.