Serologic Responses to Pneumocystis carinii Antigens in Health and Disease

Abstract

Serum antibodies to human Pneumocystis carinii antigens were measured in greater than 400 specimens from different population groups by the immunoblotting technique. Serologic responses varied during the first 2 years of life, but in children greater than or equal to 2 1/2 years and in adults antibodies to a 40-kDa band were found in greater than 85% of the specimens; antigens to bands of 66, 92, and 116 kDa were also detected frequently. The prevalence of serum antibodies in immunosuppressed patients varied at different institutions and was usually lower than that of healthy controls. Seven (41%) of 17 patients with single episodes of pneumocystosis and 13 (93%) of 14 patients with recurrent episodes followed sequentially developed active serum IgM and/or IgG antibody responses to the 40-kDa antigen. Serologic responses to P. carinii were also detected, though less frequently, by immunofluorescence. These data suggest that the 40-kDa antigen is a major marker of P. carinii infection and that immunoblotting is useful in measuring serum antibody responses to the organism in both normal and immunocompromised hosts.

Neonatal T Cells in an Adult Lung Environment Are Competent to Resolve Pneumocystis carinii Pneumonia

“…P neumocystis carinii is an opportunistic fungal pathogen that affects predominantly immunocompromised hosts including those with AIDS (1). P. carinii pneumonia (PCP) 3 remains the most frequently reported serious opportunistic infection in AIDS patients and the second highest cause of mortality among persons with AIDS in the U.S., despite the availability of effective chemoprophylaxis (2). Primary P. carinii infection is not common because immunocompetent individuals develop Ab to P. carinii by 2-3 years of age (3).…”

“…P. carinii pneumonia (PCP) 3 remains the most frequently reported serious opportunistic infection in AIDS patients and the second highest cause of mortality among persons with AIDS in the U.S., despite the availability of effective chemoprophylaxis (2). Primary P. carinii infection is not common because immunocompetent individuals develop Ab to P. carinii by 2-3 years of age (3). Recently, it has been reported that there is a relatively high incidence of P. carinii infection in autopsy specimens of children who die from sudden infant death syndrome.…”

Molecular typing of Pneumocystis jirovecii found in formalin-fixed paraffin-embedded lung tissue sections from sudden infant death victims

“…Seroepidemiological data, obtained using several antigens, indicate that primary infection by Pneumocystis organisms is one of the most frequent infections in humans, affecting more than 90 % of normal healthy children during the first 2 years of life (Meuwissen et al, 1977;Peglow et al, 1990;Pifer et al, 1978;Vargas et al, 2001;Wakefield et al, 1990a). However, only a small amount of information is available about the infection source and the clinical or pathological changes associated with this first contact with the fungus.…”

La transmission des infections àPneumocystis

“…Ces patients porteurs colonisés par le micromycète sont habituellement identifiés par la positivité de la PCR (polymerase chain reaction) Pneumocystis pratiquée sur un prélèvement respiratoire, alors que l'examen microscopique est néga-tif et que les signes cliniques et radiologiques de pneumocystose sont absents [6]. Ainsi, P. jirovecii peut être détecté chez des sujets apparemment sains, adultes et enfants (ces derniers développant dans plus de 90 % des cas une primo-infection par P. jirovecii avant l'âge de 4 ans) [7]. Les femmes enceintes, les patients sous corticoïdes, immunodéprimés, atteints de maladies systémiques ou encore de maladies pulmonaires chroniques comme la bronchopneumopathie chronique obstructive (BPCO) peuvent également être colonisés par le champignon [6].…”