Lymphocytes Forming Red Cell Rosettes in the Cold in Patients With Chronic Cold Agglutinin Disease

Lymphocytes that formed rosettes with human red cells in the cold were observed in the peripheral blood of four patients with chronic cold agglutinin disease. Similar rosettes were not observed in normals or other controls studied. Specificity for I and i red cells was demonstrated which paralleled that of the serum macroglobulins. The rosettes were inhibited by soluble I and i antigens in accordance with the specificity of the serum antibodies. Lymphocytotoxicity assays with idiotypic antisera made to the serum macroglobulins detected the same proteins on the lymphocyte surface. Evidence was obtained that the rosette test underestimated the number of cells bearing the specific cold agglutinin protein. Antisera against cold agglutinins as well as anti-IgM antibodies blocked the rosette formation. By all of these criteria, the surface lymphocyte receptors were indistinguishable from the serum antibodies of these patients.