Study of internal transcribed spacer and mitochondrial large-subunit genes of Pneumocystis carinii hominis isolated by repeated bronchoalveolar lavage from human immunodeficiency virus-infected patients during one or several episodes of pneumonia.

The detection of Pneumocystis carinii DNA in blood by PCR could be useful for studying the natural history of pneumocystosis and could also be a noninvasive diagnostic method. The results of previous studies are nevertheless conflicting. In our study, we compared three commercially available DNA extraction kits (GeneReleaser, QIAamp Tissue Kit, and ReadyAmp Genomic DNA Purification System) and proteinase K and proteinase K-phenol-chloroform treatments for the extraction of P. carinii DNA from dilutions of a P. carinii f. sp.hominis cyst suspension mixed with human whole blood. A rapid and simple nested PCR protocol which amplifies a portion of the mitochondrial large-subunit rRNA gene was applied to all the extraction products. The QIAmp Tissue Kit was the most effective kit for the isolation of amplification-ready P. carinii DNA and was used with nested PCR for the testing of whole-blood specimens from 35 immunocompetent control patients and 84 human immunodeficiency virus (HIV)-infected patients investigated for pulmonary disease and/or fever. In HIV-infected patients, P. carinii DNA was detected by nested PCR in blood samples from 3 of 14 patients with microscopically proven P. carinii pneumonia, 7 of 22 patients who were considered to be colonized with P. carinii, and 9 of 48 patients who were neither infected nor colonized with P. carinii. P. carinii DNA was not detected in blood specimens from the 35 immunocompetent patients. P. carinii DNA in blood might represent viable P. carinii organisms or DNA complexes released from pulmonary phagocytes. In conclusion, P. carinii DNA may be detected in whole blood from HIV-infected patients, but the nature and the meaning of the circulating form of P. carinii remain to be established.

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Decreased Production of Local Immunoglobulin A toPneumocystis carinii in Bronchoalveolar Lavage Fluid from Human Immunodeficiency Virus-Positive Patients

Infection and Immunity ◽

10.1128/iai.68.3.1054-1060.2000 ◽

2000 ◽

Vol 68 (3) ◽

pp. 1054-1060 ◽

Cited By ~ 9

Author(s):

A. Jalil ◽

P. Moja ◽

C. Lambert ◽

M. Perol ◽

L. Cotte ◽

...

Keyword(s):

Human Immunodeficiency Virus ◽

Bronchoalveolar Lavage ◽

Bronchoalveolar Lavage Fluid ◽

Pneumocystis Carinii ◽

Immunoglobulin A ◽

Lavage Fluid ◽

Enzyme Linked Immunosorbent Assay ◽

Local Production ◽

Immunodeficiency Virus ◽

Negative Controls

ABSTRACT An enzyme-linked immunosorbent assay and a Western blot analysis were developed to study the antibody response to Pneumocystis carinii in serum and bronchoalveolar lavage fluid from 27 human immunodeficiency virus 27 (HIV)-infected patients with P. carinii pneumonia (Pcp), 32 patients without Pcp, and 51 HIV-negative controls. Urea was used for the correct dilution of epithelial lining fluid, and albumin was used to evaluate transudation from plasma for the assessment of local production of antibodies toP. carinii. By contrast with those of immunoglobulin G (IgG), IgA responses to P. carinii were increased in serum from HIV-positive patients compared to negative controls. Local production of antibodies to P. carinii, especially IgA, was decreased in patients with Pcp. In a study of 10 patients of each group, IgG and IgA responses to gp116 from P. carinii were lower in patients with Pcp than in other groups. These results suggest that, in addition to alveolar macrophages, local antibodies may play a role in host defense against P. carinii.

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