Specific concentration of antilymphocyte antibodies in the serum cryoprecipitates of patients with systemic lupus erythematosus.

Antibodies to surface determinants of human lymphocytes, recognized both by cytotoxicity of fluorescent antibody analysis, were shown to be specifically enriched over the serum levels in cryoprecipitates from patients with systemic lupus erythematosus (SLE). The antilymphocyte antibody was shown to be cold reactive and was exclusively IgM. It was distinct from IgM anti-IgG, which was also variably concentrated in the cryoprecipitates. The question whether the antilymphocyte antibodies appear in the cryoprecipitates as complexes because of interaction with surface membrane antigens, or simply because of cold reactive properties, remains to be determined. The possible clinical relevance of the cryoprecipitation of these antibodies in systemic lupus erythematosus is discussed.