Impaired cellular immune function in patients with end-stage renal failure.

Acute leukopenia occurs in all patients during the first hour of hemodialysis with cellophanemembrane equipment. This transient cytopenia specifically involves granulocytes and monocytes, cells which share plasma membrane reactivity towards activated complement components. The present studies document that complement is activated during exposure of plasma to dialyzer cellophane, and that upon reinfusion of this plasma into the venous circulation, granulocyte and monocyte entrapment in the pulmonary vasculature is induced. During early dialysis, conversion of both C3 and factor B can be demonstrated in plasma as it leaves the dialyzer. Moreover, simple incubation of human plasma with dialyzer cellophane causes conversion of C3 and factor B, accompanied by depletion of total hemolytic complement and C3 but sparing of hemolytic C1. Reinfusion of autologous, cellophane-incubated plasma into rabbits produces selective granulocytopenia and monocytopenia identical to that seen in dialyzed patients. Lungs from such animals reveal striking pulmonary vessel engorgement with granulocytes. The activated complement component(s) responsible for leukostasis has an approximate molecular weight of 7,000-20,000 daltons. Since it is generated in C2-deficient plasma and is associated with factor B conversion, it is suggested that activation of complement by dialysis is predominantly through the altermative pathway.

In patients with chronic renal failure alterations in monokine production are a common feature. Their clinical relevance has not yet been proven. We show here a correlation between an overproduction of interleukin-(IL)-6 and tumor necrosis factor alpha (TNF alpha) upon stimulation with LPS by mononuclear cells in vitro and the clinical grade of immunodeficiency found in these patients. Higher levels of IL-6 and TNF alpha were correlated with an immunocompromized state, that is, non-responsiveness to hepatitis B vaccination, whereas patients with a better immune competence showed the same levels of these cytokines as healthy controls. Only the patients with a good immune function showed a high secretion of IL-10. The feedback mechanism of IL-10 for reducing monokine synthesis seems to be intact in these patients. Thus the secretion of IL-10 might be regarded as a compensatory mechanism which controls monokine induction by chronic renal failure and hemodialysis treatment. Immunocompromized patients who are unresponsive to hepatitis B vaccination seem to be unable to enhance IL-10 synthesis for control of monokine overproduction. This results in higher levels of IL-6 and TNF alpha that might be involved in the pathogenesis of reduced immune defense.

We investigated impaired cellular immune responses of individuals on chronic hemodialysis by using monoclonal antibodies that trigger differential pathways of T cell activation. Reduced cellular reactivity, which exists in a high proportion of such patients, can be attributed to a failure of the monocyte population to support the process of primary T cell activation in vitro. This defect results in a lack of interleukin 2 production, which is critically dependent on a monocyte-derived signal. In contrast, T lymphocyte function was found to be physiologic. Perhaps more important, the degree of monocyte dysfunction in vitro correlated with the same patients' in vivo responses to hepatitis B vaccination. Addition of recombinant human interleukin 2 fully reconstituted their deficient immune response in vitro.