Changes in coagulation factors, complement, immunoglobulins, and immune complex concentrations with plasma exchange.

Seventeen patients with a spectrum of immunologically-related disorders were studied before and immediately after plasma exchange (PE) for changes in coagulation factors, complement, immunoglobulins, and immune complex levels. Each PE replaced 50 per cent of the plasma volume with 5% albumin and saline. With PE, coagulation profiles indicated a decrease of 23 to 55 per cent in the levels of fibrinogen, Factors II, V, VII, VIII, IX, X, XI, XII, and Fletcher factor. Only minimal changes were noted in the prothrombin time and activated partial thromboplastin time. Most coagulation factors, except fibrinogen, returned to baseline by 48 hours. Following three PE/week, fibrinogen was reduced by 51 per cent; other factors were not significantly altered. C3 and C4 fell by 35 to 40 per cent with each PE; these approached baseline by 24 hours. Immunoglobulins (G,A,M) were reduced by 34 +/- 3,37 +/- 3 and 34 +/- 3 per cent, respectively. After three PE, the total immunoglobulins were decreased by 50 to 55 per cent. Five of eight patients who had three or more PE developed hypogammaglobulinemia (IgG less than 450 mg/dl). Immune complexes were reduced by 50 +/- 4 per cent with each PE. Multiple exchanges in five patients led to a greater reduction (80 +/- 6%). Thus PE was an effective means of reducing immune complexes but led to hypogammaglobulinemia and hypofibrinogenemia.