[Heterogeneity and avidity of autoantibodies reacting with DNA].

Subpopulations of auto-antibodies to DNA were isolated by affinity procedures from sera of two patients with SLE and from IgG of healthy donors after ion-exchange chromatography ("hidden" auto-antibodies). It was found that two subpopulations of auto-antibodies are present in SLE sera just as fractions of "hidden" auto-antibodies consist of three subpopulations. The dissociation constants were measured by ELISA for the interaction of all subpopulations of auto-antibodies to DNA. It is shown that KD are very high and identical no matter of whether they were prepared from SLE sera of from IgG of healthy donors. The analogy of two types of auto-antibodies (SLE auto-antibodies and "hidden" auto-antibodies) is discussed in this paper.