Pneumocystis jiroveci is an opportunistic fungal organism (previously classified as a protozoa) that can cause life-threatening pulmonary infections in a number of primary immunodeficiencies. Infections are characterized by fever, cough, and profound hypoxia. This infection is typically found in immunodeficiencies with severe T cell dysfunction (SCID) or impaired activation of macrophages (X-linked Hyper IgM). HIV is the primary cause of PJP infections due to secondary immunodeficiency.
SCID - Pneumocystis jiroveci pneumonia (PJP) is a very common opportunistic infection found in patients at initial presentation.
X-linked Hyper IgM - PJP is the initial manifestation of disease in 30% of patients. Activation of macrophages by intact CD40-CD40L signaling is necessary in order to clear Pneumocystis infection
NEMO deficiency - PJP infections have been reported in patients with this disease.
Wiskott-Aldrich syndrome - In one study, PJP occured in 9% of patients with this disease.
Dyskeratosis Congenita -In the infant form of this disease (also known as Hoyeraal-Hreidarsson syndrome), PJP is very a common infectious complication.
DOCK8 Deficiency - Patients can have significant defects in T cell immunity and are susceptible to PJP.
STAT3 Deficiency - PJP has been reported in a small number of patients with STAT3 deficiency (mainly during infancy).
XLA - PJP has been reported in a small number of patients with XLA but it does not appear to be a key disease feature.