Do humoral factors removed by plasmapheresis suppress the cellular immune system in cryoglobulinemia?

The efficacy of plasmapheresis (PP) is believed to be primarily related to the removal of plasma humoral factors. Little is known, however, about the effect of solute removal on cellular systems. The effect of the presence of cryoprecipitable proteins (CPPT) on mononuclear blastogenesis (MNB) and polymorphonuclear cell phagocytosis (PMN-P) was studied. MNB stimulated by concanavalin A (Con A), phytohemagglutinin (PHA), and pokeweed mitogen (PWM) was significantly inhibited in cryoglobulinemic (CG) patients to 70, 75, and 60% that of normal controls, respectively. PMN-P were significantly suppressed to 30% that of normals. CPPT purified from cryoglobulinemic plasmas, type I and type III CG, exhibited higher suppressive effects (and in a concentration dependent manner) on normal MNB and PMN-P than albumin used as a control. The studies indicate that patients with CG have defective leukocyte function and that CPPT have suppressive effects on normal leukocyte function in vitro. Removal of plasma CPPT may improve the immunologic status of CG patients.