The Formation in Vitro of Cold Auto-Hemagglutinins with Anti-I Specificity

Abstract

The formation in vitro of cold auto-hemagglutinins as they occur in the cold hemagglutinin syndrome has been studied. Samples of bonemarrow, obtained from patients who showed a high serum titer of cold auto-hemagglutinins, were incubated with radioactive amino acids. The synthesized immunoglobulins were analyzed by autoradiography of the immunoelectrophoretic pattern of the culture fluid. The autoradiographic patterns were similar to those for the serum of the corresponding patients. The synthesis of the cold auto-hemagglutinins was studied by incubating I and i₂ red cells with the culture fluid at 4°C and subsequently eluting these cells. The concentrated eluates contained only IgM molecules with anti-I specificity and type K antigenic determinants on the L chain. Because these properties are characteristic for cold agglutinins, it may be concluded that the bone-marrow samples from these patients had synthesized cold auto-hemagglutinins in vitro. Plasma cells may be regarded as being involved in this synthesis because of their IgM-positive fluorescence; no positive lymphoid cells were observed.