Immunodeficiency is a potentially under recognized aspect of underlying infections, such as community-acquired pneumonia (CAP). Our aim was to determine the prevalence of immunodeficiency in patients admitted to a large community hospital with CAP.
We enrolled 100 consecutive patients with CAP from February 2017 to April 2017. Serum IgG, IgM, IgA, IgE and IgG serotypes for streptococcus pneumoniae were collected for each patient, along with pneumococcal vaccination status. CURB-65 score and length of hospital stay (LOS) were calculated.
27 of 100 patients had IgG hypogammaglobulinemia (average 561 mg/dL, SD ± 118), and 9 had IgG hypergammaglobinemia (1888 mg/dL ± 261). 23 of 100 patients had IgM hypogammaglobinemia (34 mg/dL ± 10), and 2 had IgM hypergammaglobinemia (491 mg/dL ± 73). 6 of 100 had IgA hypogammaglobinemia (38 mg/dL ± 18), and 5 had IgA hypergammaglobinemia (557 mg/dL ± 138). The average hospital length of stay for patients with IgG hypogammaglobinemia was 2.68 days longer than patients with normal serum IgG (6.63 versus 3.95 days, p=0.029, CI= 0.3-5.07). There was no association between IgG hypogammaglobulinemia and CURB 65, presence of smoking history, obesity, or diabetes mellitus. In 14 of 100 patients undergoing additional evaluation, one was diagnosed with multiple myeloma, one with selective IgA deficiency, and three with specific antibody deficiency.
In patients admitted with CAP, IgG and IgM hypogammaglobulinemia are common, and IgG hypogammaglobulinemia is associated with an increased length of hospitalization. Screening CAP patients with immunoglobulin levels and streptococcus pneumoniae titers may uncover underlying immunodeficiency or immuno-proliferative disorders.