EVIDENCE FOR IMMUNE-COMPLEXES INVOLVING ANTI-LYMPHOCYTE ANTIBODIES ASSOCIATED WITH HYPOCOMPLEMENTAEMIA IN CHRONIC LYMPHOCYTIC LEUKEMIA (CLL)

Abstract

Unmeasurable total hemolytic complement (C) was observed in serum of a patient with untreated CLL and recurrent non-hereditary angioedema. Analysis of C [complement] components immunochemically demonstrated a marked reduction of C1q [q fragment of the 1st C component] and C1s inhibitor, undetectable C1r, C1s and an elevated B [C3 proactivator]. Hemolytic C1, C4 and C2 were less than 5% of normal; functional C1s inhibitor was absent. Cryoglobulin and C1q precipitins were present in serum. There were high levels of cold-reactive antilymphocyte antibody, determined by C-dependent cytotoxicity and indirect immunofluorescence. The antibody exhibited specificities for autologous lymphocytes and lymphocytes from normal donors; cytotoxic activity for autologous leukemia cells was removed by absorption with normal isologous tonsil lymphocytes. Specific enrichment of this antibody relative to the serum level was demonstrated in the cryoglobulin and its isolated 19S fractions. Free lymphocyte surface antigen was also demonstrated by gel diffusion using specific rabbit antilymphocyte antiserum. The presence of pathogenetically significant circulating complexes of lymphocyte surface antigen and specific antibody is suggested in certain patients with CLL.