Pneumocystis carinii Infection: Evidence for High Prevalence in Normal and Immunosuppressed Children

Abstract

Using Pneumocystis carinii organisms propagated through three passages in embryonic chick epithelial lung cultures, specific antigens and antisera were prepared for use in counterimmunoelectrophoresis and indirect immunofluorescent antibody techniques. These methods proved to be specific and sensitive for the detection of P. carinii antigen and antibody, respectively, in sera, and were applied to the study of cancer patients with P. carinii pneumonitis (PCP), cancer patients without pneumonitis, and normal children. Antigenemia was detected in 95% of patients with PCP, in 15% of cancer patients without pneumonitis, and in none of the normal children tested. In cross-sectional and longitudinal studies of normal infants and children, acquisition of serum antibody to P. carinii was demonstrated to occur progressively with increase in age. By 4 years of age two thirds of the normal children were found to have antibody to P. carinii in titers of 1:16 or greater. These studies indicate that subclinical P. carinii infection is highly prevalent in normal children, analogous to other opportunistic infections where active disease is manifest predominantly in the compromised host.

Interstitial pneumonia with subpleural sparing and weight loss

“…PJP is the most frequent opportunistic infection in patients with HIV infection and a low CD4 count. The primary mode of transmission is via the airborne route and it remains dormant unless the patient becomes immunosuppressed; however, this may not account for all cases [1] . In the 60 s and 70 s its incidence was higher in patients with hematologic malignancies, while in the 80 s the prevalence increased dramatically with the emergence of the HIV epidemic.…”

Opinions on Pneumocystis jirovecii prophylaxis in autoimmune neuromuscular disorders

“…1 Some degree of indolent PJ colonization in the lung may be normal as PJ DNA can be isolated from oropharyngeal washings of up to 20% of immunocompetent individuals without lung disease, and in the lung tissue of up to 65% to 78% of individuals at autopsy. [2][3][4] PJ was first recognized as a pathogen causing interstitial pneumonia in malnourished children during World War II. 1 It remained an uncommon infection until the start of the acquired immunodeficiency syndrome (AIDS) epidemic, during which low CD4 count in human immunodeficiency virus (HIV)-infected individuals became a widely recognized risk factor.…”

“…Although capable of causing a life‐threatening pneumonia in immunocompromised individuals, Pneumocystis jirovecii (PJ), formerly known as Pneumocystis carinii , is a fungus that is ubiquitously present in the environment 1 . Some degree of indolent PJ colonization in the lung may be normal as PJ DNA can be isolated from oropharyngeal washings of up to 20% of immunocompetent individuals without lung disease, and in the lung tissue of up to 65% to 78% of individuals at autopsy 2‐4 …”

Sero-Epidemiology of Pneumocystis Infection among Infants, Children, and Adults in Chile

“…Serologic surveys show that seroconversion resulting from the primary infection is common in children [15][16][17]. Furthermore, serologic surveys among children and adults in United States, United Kingdom, Uganda and Gambia show evidence of antibody response to infection in a majority of heathy and immunosuppressed populations [18][19][20].…”