Pneumocystis carinii was identified by immunofluorescence in only one (placebo) of 73 nasopharyngeal aspirates from children with pneumonia.
The most common opportunistic infection in children with XHIM is a lung disease known as Pneumocystis carinii pneumonia (PCP).
The most common telltale symptom, however, is PCP; in fact, the frequency of Pneumocystis carinii pneumonia in children with hyper-IgM syndrome was a useful clue to geneticists searching for the mutation that causes the disorder.
Pneumocystis carinii causes pneumonia in immunosuppressed individuals such as patients being treated with chemotherapy or people with AIDS.
Immunodeficient individuals are at higher risk for infection with Pneumocystis carinii and are frequently put on a regular preventive drug regimen of trimethoprim sulfa and/or inhaled pentamidine to avoid pneumocystis pneumonia.