X-linked agammaglobulinemia in community-acquired pneumonia cases revealed by immunoglobulin level screening at hospital admission.

In children with primary immunodeficiencies, the onset of symptoms precedes the diagnosis and the initiation of appropriate treatment by months or years. This delay in diagnosis is due to the fact that while these disorders are rare, some of the infections seen in immunodeficient patients are common. Defective antibody production represents the largest group among these disorders, with otitis, sinusitis and pneumonia as the most frequent initial manifestation. We performed a prospective study of humoral immunity in children hospitalized due to community-acquired pneumonia in tertiary care hospital. Out of 254 patients (131 boys, 123 girls, median age 4.5 years) recruited over 3 years, we found 2 boys (age 11 and 21 months) lacking serum immunoglobulins and circulating B cells. Subsequent genetic analysis confirmed diagnosis of X-linked agammaglobulinemia. Despite their immunodeficiency, the pneumonia was uncomplicated in both patients and did not call for immunological evaluation. However, the immunoglobulin screening at admission allowed for an early diagnosis of the immunodeficiency and timely initiation of immunoglobulin substitution, the key prerequisite for a favorable course of the disease.Simple and inexpensive immuno-globulin measurement during the manage-ment of hospitalized children with community-acquired pneumonia may help in early identification of patients with compromised humoral immunity and prevent serious complications.