Prophylaxis against infections with low-dose intravenous immunoglobulins (IVIG) in chronic lymphocytic leukemia. Results of a crossover study.

BACKGROUND In a recently reported study, low doses of intravenous immunoglobulins (IVIG) were shown to be as effective as high doses in protecting chronic lymphocytic leukemia (CLL) patients against infections, although a control group was not included. With this background we started a crossover study of low-dose IVIG prophylaxis aimed at investigating its superiority over empirical treatment of infections. MATERIALS AND METHODS Forty-two CLL patients with hypogammaglobulinemia (IgG < 600 mg/dL) and/or a history of at least one episode of severe infection in the 6 months preceding inclusion in the study were randomly allocated to receive either an infusion of 300 mg/kg IVIG every 4 weeks for 6 months or no treatment. Then they were switched to observation or IVIG for another 12 months; finally, they received IVIG or no therapy for 6 more months. RESULTS A significantly lower incidence of infectious episodes was observed during IVIG prophylaxis in 30 patients who completed the 6-month period of either observation or IVIG therapy. The same applied to the 17 patients who completed 12 months of either observation or IVIG prophylaxis. Interestingly, the restoration of serum IgG levels obtained in 17 out of 25 patients (mean percent value of IgG increase, 41.8%) did not parallel a decrease in the number of infectious episodes. CONCLUSIONS A protective effect against infections is demonstrated for low-dose IVIG in the present study. A benefit was shown in patients who completed either 12 or 6 months of IVIG prophylaxis; however, even this low-dose treatment is not a cost effective way to prevent infection in CLL patients.