Tissue distribution of Histoplasma capsulatum in deceased people living with HIV assessed by minimally invasive tissue sampling: An autopsy-based case series in the Brazilian Amazon.

This observational autopsy-based case series characterized the tissue distribution of Histoplasma capsulatum in deceased people living with HIV (PLHIV) using minimally invasive tissue sampling (MITS). This study included 59 deceased PLHIV admitted to a tertiary referral hospital in the Brazilian Amazon between October 2020 and June 2022. Tissue and body fluid samples were analyzed using fungal culture, histopathology, conventional polymerase chain reaction (PCR), and quantitative PCR (qPCR). H. capsulatum was detected in 27 of 59 (45.8%) patients, including nine (33.3%) with multi-organ detection of H. capsulatum. The liver (9/27, 33.3%) and lungs (8/27, 29.6%) were the most frequently involved organs in this series. qPCR amplification was detected across multiple tissues, with lower median Ct values in the lung (40.3, range 37.0-45.0) and liver (41.0, range 38.0-44.0) than in cerebrospinal fluid (43.5, range 40.0-48.0) and brain tissue (44.0, range 41.0-47.0), suggesting greater fungal DNA detection in the lungs and liver. Molecular methods detected fungal DNA in tissue samples that were negative by culture, although several amplification signals occurred near the assay detection limit. H. capsulatum showed heterogeneous tissue distribution in deceased PLHIV, with the liver and lungs being the most frequently involved organs. Molecular methods complemented conventional diagnostic techniques by identifying fungal DNA in culture-negative tissues, providing a more comprehensive assessment of tissue involvement. These findings improve understanding of disseminated histoplasmosis in advanced HIV infection and may inform future tissue-based diagnostic strategies.