Clinical relevance of hypogammaglobulinemia, clinical and biologic variables on the infection risk and outcome of patients with stage A chronic lymphocytic leukemia

- Low levels of IgG at diagnosis were recorded in 19.9% of stage A patients with CLL.
- Low levels of IgG were observed by an additional 20% of patients during the disease.
- IgG levels at diagnosis were not associated with an increased risk of infection.
- A more aggressive disease was associated with an increased rate of infections.

The prognostic effect of hypogammaglobulinemia (HGG), clinical and biologic characteristics on the infection risk and outcome has been retrospectively analyzed in 899 patients with stage A chronic lymphocytic leukemia (CLL). Low levels of IgG were recorded in 19.9% of patients at presentation, low levels of IgM and/or IgA in 10.4% and an additional 20% of patients developed HGG during the course of the disease. Before the start of any treatment, 160 (12.9%) patients experienced at least one grade ≥3 infection requiring a systemic anti-infective treatment and/or hospitalization. While IgG levels at diagnosis were not associated with an increased risk of grade ≥3 infection or with an adverse outcome, a significantly increased rate of grade ≥3 infections was recorded in patients with unmutated IGHV (p = 0.011) and unfavorable FISH aberrations (p = 0.009). Late onset HGG, more frequently recorded in patients with Rai stage I-II (p = 0.001) and unmutated IGHV (p = 0.001), was also associated with a higher rate of severe infections (p = 0.002).These data indicate that, stage A patients with clinical and biologic characteristics of a more aggressive disease develop more frequently late onset HGG, grade ≥3 infections and require a closer clinical monitoring.