Browsing by Subject "Pneumocystis"

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    Open Access
    Humoral immune responses to Pneumocystis jirovecii antigens in HIV-infected and uninfected young children with pneumocystis pneumonia
    (Public Library of Science, 2013) Djawe, Kpandja; Daly, Kieran R; Levin, Linda; Zar, Heather J; Walzer, Peter D
    BACKGROUND: Humoral immune responses in human immunodeficiency virus (HIV)-infected and uninfected children with Pneumocystis pneumonia (PcP) are poorly understood. METHODS: Consecutive children hospitalized with acute pneumonia, tachypnea, and hypoxia in South Africa were investigated for PcP, which was diagnosed by real-time polymerase chain reaction on lower respiratory tract specimens. Serum antibody responses to recombinant fragments of the carboxyl terminus of Pneumocystis jirovecii major surface glycoprotein (MsgC) were analyzed. RESULTS: 149 children were enrolled of whom 96 (64%) were HIV-infected. PcP occurred in 69 (72%) of HIV-infected and 14 (26%) of HIV-uninfected children. HIV-infected children with PcP had significantly decreased IgG antibodies to MsgC compared to HIV-infected patients without PcP, but had similar IgM antibodies. In contrast, HIV-uninfected children with PcP showed no change in IgG antibodies to MsgC, but had significantly increased IgM antibodies compared to HIV-uninfected children without PCP. Age was an independent predictor of high IgG antibodies, whereas PcP was a predictor of low IgG antibodies and high IgM antibodies. IgG and IgM antibody levels to the most closely related MsgC fragments were predictors of survival from PcP. CONCLUSIONS: Young HIV-infected children with PcP have significantly impaired humoral immune responses to MsgC, whereas HIV-uninfected children with PcP can develop active humoral immune responses. The children also exhibit a complex relationship between specific host factors and antibody levels to MsgC fragments that may be related to survival from PcP.
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    Pneumocystis jirovecii pneumonia in tropical and low and middle income countries: a systematic review and meta-regression
    (Public Library of Science, 2013) Lowe, David M; Rangaka, Molebogeng X; Gordon, Fabiana; James, Chris D; Miller, Robert F
    Objective: Pneumocystis jirovecii pneumonia (PCP), the commonest opportunistic infection in HIV-infected patients in the developed world, is less commonly described in tropical and low and middle income countries (LMIC). We sought to investigate predictors of PCP in these settings. Design Systematic review and meta-regression. METHODS: Meta-regression of predictors of PCP diagnosis (33 studies). Qualitative and quantitative assessment of recorded CD4 counts, receipt of prophylaxis and antiretrovirals, sensitivity and specificity of clinical signs and symptoms for PCP, co-infection with other pathogens, and case fatality (117 studies). RESULTS: The most significant predictor of PCP was per capita Gross Domestic Product, which showed strong linear association with odds of PCP diagnosis (p<0.0001). This was not explained by study design or diagnostic quality. Geographical area, population age, study setting and year of study also contributed to risk of PCP. Co-infection was common (444 episodes/1425 PCP cases), frequently with virulent organisms. The predictive value of symptoms, signs or simple tests in LMIC settings for diagnosis of PCP was poor. Case fatality was >30%; treatment was largely appropriate. Prophylaxis appeared to reduce the risk for development of PCP, however 24% of children with PCP were receiving prophylaxis. CD4 counts at presentation with PCP were usually <200×10 3/ ml. CONCLUSIONS: There is a positive relationship between GDP and risk of PCP diagnosis. Although failure to diagnose infection in poorer countries may contribute to this, we also hypothesise that poverty exposes at-risk patients to a wide range of infections and that the relatively non-pathogenic P. jirovecii is therefore under-represented. As LMIC develop economically they eliminate the conditions underlying transmission of virulent infection: P. jirovecii , ubiquitous in all settings, then becomes a greater relative threat.