Serum antibody levels to the Pneumocystis jirovecii major surface glycoprotein in the diagnosis of P. jirovecii pneumonia in HIV+ patients

• Published in: PloS one 2010-12, Vol.5 (12), p.e14259-e14259
• Main Authors: Djawe, Kpandja, Huang, Laurence, Daly, Kieran R, Levin, Linda, Koch, Judy, Schwartzman, Alexandra, Fong, Serena, Roth, Brenna, Subramanian, Anuradha, Grieco, Katherine, Jarlsberg, Leah, Walzer, Peter D
• Format: Article
• Language: English
• Subjects: Acquired immune deficiency syndrome; African Americans; AIDS; Antigens; Antiretroviral drugs; Bronchoalveolar Lavage Fluid; Chemokines; Chronic obstructive pulmonary disease; Critical care; Development and progression; Diagnosis; Diagnostic systems; Drug therapy; Environmental health; Enzyme-linked immunosorbent assay; Enzyme-Linked Immunosorbent Assay - methods; Enzymes; Epidemiology; Female; Glycoproteins; Health aspects; HIV; HIV Infections - complications; HIV Infections - microbiology; HIV Infections - virology; HIV patients; HIV Seropositivity; Hospitals; Human immunodeficiency virus; Humans; IgG antibody; Immunocompromised hosts; Immunoglobulin G; Immunoglobulin G - chemistry; Immunoglobulin M; Immunoglobulin M - chemistry; Immunoglobulins; Infections; Infectious diseases; Infectious Diseases/Epidemiology and Control of Infectious Diseases; Infectious Diseases/Fungal Infections; Infectious Diseases/HIV Infection and AIDS; Infectious Diseases/Respiratory Infections; Internal medicine; Lungs; Male; Medical diagnosis; Medicine; Membrane Glycoproteins - chemistry; Mortality; Multivariate Analysis; Patients; Pneumocystis; Pneumocystis carinii - metabolism; Pneumonia; Pneumonia, Pneumocystis - diagnosis; Pneumonia, Pneumocystis - microbiology; Predictive Value of Tests; Public Health and Epidemiology/Global Health; Public Health and Epidemiology/Infectious Diseases; Respiratory Medicine/Respiratory Infections; Sensitivity; Sensitivity and Specificity; Studies; Toxoplasma gondii; Veterans
• ISSN: 1932-6203; 1932-6203
• DOI: 10.1371/journal.pone.0014259

Pneumocystis jirovecii remains an important cause of fatal pneumonia (Pneumocystis pneumonia or PcP) in HIV+ patients and other immunocompromised hosts. Despite many previous attempts, a clinically useful serologic test for P. jirovecii infection has never been developed. We analyzed serum antibody responses to the P. jirovecii major surface glycoprotein recombinant fragment C1 (MsgC1) in 110 HIV+ patients with active PcP (cases) and 63 HIV+ patients with pneumonia due to other causes (controls) by an enzyme-linked immunosorbent assay (ELISA). The cases had significantly higher IgG and IgM antibody levels to MsgC1 than the controls at hospital admission (week 0) and intervals up to at least 1 month thereafter. The sensitivity, specificity and positive predictive value (PPV) of IgG antibody levels increased from 57.2%, 61.7% and 71.5% at week 0 to 63.4%, 100%, and 100%, respectively, at weeks 3-4. The sensitivity, specificity and PPV of IgM antibody levels rose from 59.7%, 61.3%, and 79.3% at week 0 to 74.6%, 73.7%, and 89.8%, respectively, at weeks 3-4. Multivariate analysis revealed that a diagnosis of PcP was the only independent predictor of high IgG and IgM antibody levels to MsgC1. A high LDH level, a nonspecific marker of lung damage, was an independent predictor of low IgG antibody levels to MsgC1. The results suggest that the ELISA shows promise as an aid to the diagnosis of PCP in situations where diagnostic procedures cannot be performed. Further studies in other patient populations are needed to better define the usefulness of this serologic test.