Prevalence and risk factors for disseminated Talaromyces marneffei in HIV-infected patients in China
August 26 2016
The prevalence of disseminated Penicillium marneffei (now known as Talaromyces marneffei) infection in HIV-infected patients is unknown. 8131 archived HIV-infected patient serum samples were tested for T. marneffei-specific mannoprotein antigen between 2004 and 2011 in Guangzhou, China in order to evaluate the prevalence and risk factors for this infection.
Previous studies have shown that environmental predictors, seasonality and changes in CD4 count affect the prevalence of T. marneffei, with HIV-infected patients with a CD4 count <200 cells/µL at particular risk. However, data regarding these factors in Chinese patients is lacking.
The cell-wall mannoprotein, Mplp has previously been shown to be a potential biomarker for the serodiagnosis of T.marneffei and the authors established a double-antibody sandwich ELISA for Mplp antigen with high sensitivity and specificity (1). In this retrospective analysis, this immunoassay was used to assess the prevalence of Talaromyces among HIV-infected patients in Guangzhou. The correlation between the CD4 count and the seasonality, and the Mplp antigen-positive rate was also analysed in order to assess risk factors.
HIV-1 infection was identified by routine blood-screening procedures and confirmed by Western blot . The serum samples were tested for Mplp antigen by sandwich ELISA, and for galactomannan (GM) by PlateliaTM Aspergillus enzyme immunoassay (Bio-Rad Laboratories, Redmon, WA, USA). PlateliaTM has previously been shown to react positively to Talaromyces species and so the concordance rate between Mplp and GM was calculated. 2686 out of the 8131 cases also had available CD4 counts. Data on average temperature and relative humidity were collected by the Guangdong Meteorological Service.
The number of cases of penicilliosis increased significantly throughout the study period, in parallel with the number of cases of HIV infection. The average prevalence of Mplp antigenemia was 9.36% (increasing from 5.17% in 2004 to 12.58% in 2010, then decreasing to 8.25% in 2011). The prevalence was also strongly related to the progression of HIV to AIDS, indicating an association with CD4 count (Most cases of Talaromyces infection occurred in patients with a CD4 count of <50 cells/µL). A good concordance rate between Mplp and GM was found (86.55%), similar to previous reports. The results also demonstrated that the prevalence of active T. marneffeiwas associated with humidity but not temperature.
This immunoassay was a good serodiagnostic tool for Talaromyces in HIV-infected patients and Mplp antigen screening in HIV-infected patients may prevent mortality associated with Talaromyces infections.