FURTHER IMMUNOLOGICAL STUDIES OF SERA CONTAINING ANTI-MITOCHONDRIAL ANTIBODIES, TYPE-M5

Abstract

All of 15 sera containing anti-mitochonchondrial antibodies (AMA), type M5, reacted in ELISA [enzyme-linked immunosorbent assay] with ss[single-stranded]DNA; only 4 had anti-nuclear antibodies as demonstrated by immunofluorescence technique. Twelve of 15 had biological false-positive seroreaction for syphilis and 7 of 11 cases investigated had a positive lupus anti-coagulant test. Cold agglutinins were present in 11 sera. Hyper-.gamma.-globulinemia was not a prominent finding, but complement C4 values below the lower limit were common in spite of C3 within the normal range. Absorption of IgG fractions from 3 different sera with cardiolipin eliminated the reaction with ssDNA and mitochondria, supporting a certain degree of cross-reactivity among the antibodies. The presence of AMA, type M 5, seemed to discriminate a group of patients with symptoms often consistent with systemic lupus erythematosus although some of the most prominent findings were often absent.