[Secondary hypogammaglobulinemia with recurrent opportunistic pulmonary infection]

Secondary hypogammaglobulinemia may be a relevant predisposing condition in patients with recurrent bacterial upper airway disease (pneumonia, sinusitis) or first-time opportunistic infection, particularly if additional immunosuppressive factors like underlying hematological disease or immunosuppressive therapy are present. As an example, we present a retired farmer with myeloma, treated Hodgkin-lymphoma and hypogammaglobulinemia suffering from the third episode of Rhodococcus equi pneumonia. Screening for hypogammaglobulinemia is recommended in patients with unexplained recurrent bacterial airway infection or first time opportunistic disease, particularly with micro-organisms controlled by humoral immunity. Screening should include the analysis of total immunoglobulin levels (IgA, IgG and IgM). If results are ambiguous, tetanus toxoid and pneumococcal polysaccharide vaccine should be administered with measurement of specific antibody titer before and one month after vaccination. An adequate antibody response largely excludes a clinically significant humoral immunodeficiency. If hypogammaglobulinemia is present in a patient with recurrent or opportunistic infections, periodical substitution of IVIG in a dose and frequency to prevent further infectious episodes should be initiated. This is usually achieved with an IVIG-dose of 0.4g/kg body weight every 3 - 4 weeks to reach a trough IgG-level of 5 - 7g/L.