Should mild hypogammaglobulinemia be managed as severe hypogammaglobulinemia? A study of 389 patients with secondary hypogammaglobulinemia

Background: Although secondary hypogammaglobulinemia is more frequent than primary hypogammaglobulinemia, its etiology andmanagement are poorly described, particularly for mild hypogammaglobulinemia. Methods: This retrospective observational study included all adult patients with a gammaglobulin level <6.4 g/L on serum electrophoresis identified at Dijon teaching hospital between April and September 2012. Clinicobiological features, etiologies and infectious complications were collected at inclusion and compared between group 1 (gammaglobulin <5 g/L, severe hypogammaglobulinemia), and group 2 (gammaglobulin <6.4 and >= 5 g/L, mild hypogammaglobulinemia). Results: Among the 4011 serum electrophoreses, 570 samples from 389 patients had gammaglobulin levels below 6.4 g/L: 156 (40%) in group 1 and 233 (60%) in group 2. Mean age +/- SD was 67 (15) years, and sex ratio was 1.04 (M/F) with no difference between the two groups. An etiology was identified in 79% and 58% of patients in groups 1 and 2, respectively (p < 0.0001). The main etiologies were similar in both groups and included malignant hemopathy treated with cytostatic agents (n = 129, 33%), smoldering or newly-diagnosed hemopathy without treatment (n = 49, 13%) and immunosuppressive treatment (n = 91, 23%). The incidence of hypogammaglobulinemia-related infections was 22/100/year, with no significant difference between the two groups (p = 0.17). Vaccination coverage against pneumococcus was 33%, and higher in group 1 (46% vs. 24%; p < 0.0001). When no cause was known at inclusion, an etiology was discovered in 22/130 patients (17%), 11 in each group. Conclusions: Though mild hypogammaglobulinemia does not meet the classical criteria for hypogammaglobulinemia (<5 g/L), the etiology and infectious risk are similar. It therefore requires investigation and vaccination. (C) 2014 European Federation of Internal Medicine. Published by Elsevier B.V. All rights reserved.