An evaluation of Mp1p antigen screening for talaromycosis in HIV-infected antiretroviral therapy-naïve population in Guangdong, China

Abstract

Background

Talaromycosis is one of the most common opportunistic infections in human immunodeficiency virus (HIV) infected patients. However, few researches have explored the prevalence in Southern China and fully assessed the value of the Mp1p antigen screening for the diagnosis of talaromycosis.

Methodology/Principal findings

We performed a cross-sectional study of HIV-infected antiretroviral therapy (ART)-naïve adult patients who were seen in 2018 at Guangzhou Eighth People’s Hospital, Guangzhou Medical University. Serum samples collected from all the 784 enrolled patients were tested for Mp1p antigen using double-antibody sandwich enzyme-linked immunosorbent assay. A culture of pathogen was conducted in 350 clinically suspected patients to confirm talaromycosis. The overall prevalence of talaromycosis based on the Mp1p antigen detection was 11.4% (89/784) and peaked at 32.2% (75/233) in patients with CD4 ⁺ ≤50 Nr/μl. Logistic regression analysis found Mp1p antigen positive rate decreased with the increase in CD4 ⁺ counts (OR 0.982, 95% CI 0.977–0.987, P<0.01). The optimal cut-off point of the CD4 ⁺ count was 50 Nr/μl or less. Among the 350 patients received both fungal culture and Mp1p antigen detection, 95/350 (27.1%) patients were culture-positive for a Talaromyces marneffei, 75/350 (21.4%) patients were Mp1p antigen positive. The Mp1p antigen assay showed a good agreement to the culture of pathogen, and the sensitivity, specificity, positive predictive value, negative predictive value and kappa value was 71.6% (68/95), 97.3% (248/255), 90.7% (68/75), 90.2% (248/275), and 0.737, respectively. The screening accuracy of the Mp1p antigen assay in patients with CD4 ⁺ counts of ≤50 Nr/μl was superior to that in those with higher CD4 ⁺ counts.

Conclusions/Significance

Mp1p antigen screening can be an effective tool for more efficient diagnosis of Talaromycosis, especially in HIV/AIDS patients with low CD4 ⁺ counts. Future validation studies are needed.

Author summary

Talaromyces marneffei ( T. marneffei) is an important human immunodeficiency virus (HIV)-associated opportunistic pathogen in Southern China, and its infection is a leading cause of HIV-associated death. Properly and early antifungal treatment and timely antiretroviral therapy (ART) would reduce the mortality. Currently, the gold standard of diagnosis for talaromycosis is culture. The Mp1p antigen assay, the detection for a T. marneffei-specific protein, would be a reliable biomarker of T. marneffei infection in clinical practices. The CD4 ⁺ counts are an indicator of human immune system. The less CD4 ⁺ counts the weaker immune function and much possible the infection of opportunistic pathogen. In this study, we found that HIV patients with talaromycosis had a lower CD4 ⁺ count and more advanced disease compared to those without. The prevalence of talaromycosis based on the Mp1p antigen detection was significantly higher in patients with low CD4 ⁺ count than those with without. What’s more, the Mp1p antigen screening was an effective tool to motivate the diagnosis for talaromycosis in patients with CD4 ⁺ ≤ 50 Nr/μl, and in turn to drive the initiation of antifungal treatment and ART, which would help the reduction of mortality and the improvement of treatment outcome.