Infections and serum IgG levels in patients with chronic lymphocytic leukemia.

To review our policy of prophylactic treatment with intravenous immunoglobulin (i.v.IG) in chronic lymphocytic leukemia (CLL), we analyzed the infection history, serum IgG levels (S-IgG) and disease stage of 146 patients who were treated and followed at our institution in 1980-1989. S-IgG was available for 98 patients: 55% were hypogammaglobulinemic and 56% had had at least one severe infection. There were significant associations between S-IgG and the occurrence of infections (p less than 0.01) and disease stage (p less than 0.02). There was also a significant association between disease stage and occurrence of infections (p less than 0.001). Severe infections tended to accumulate in patients with subnormal S-IgG and advanced disease stage. Totally, 292 infections were recorded, and the incidence of moderate to severe infections was 0.47 per patient year. Infection mortality was high: 42 patients died of a severe infection (46% of all causes of death). Patients with a low S-IgG and advanced disease stage are the most susceptible to death from infection and would be most likely to benefit most from i.v.IG prophylaxis; however, the cost of this therapy is so high that strict individual consideration still remains crucial for treatment decisions.