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Elevated immune and neuronal injury markers in MSM with HIV and PrEP suggest lifestyle factors, beyond HIV, drive persistent inflammation. 

According to a study published in June 2025 in the issue of Infectious Diseases explored People living with HIV (PWH) who were acquiring antiretroviral therapy (ART) continued to demonstrate the signs of immune activation, potentially influenced by both infection-specific and behavioral factors.   

Researchers evaluated the biomarkers of immune activation and neuronal injury in PWH on ART compared to lifestyle-matched controls.   

They collected cerebrospinal fluid (CSF) and blood samples from 50 men who had sex with men (MSM) on ART who were HIV-positive, 50 MSM with HIV-negative using preexposure prophylaxis (PrEP), and 25 HIV-negative controls not receiving PrEP and estimated β2-microglobulin, neopterin, and neurofilament light protein (NfL) levels, and recorded cytomegalovirus and herpes simplex virus-2 serostatus, along with data on sexually transmitted bacterial infections.   

The results showed no significant difference in serum and CSF β2-microglobulin and neopterin levels between MSM with HIV and MSM on  PrEP. However, both MSM groups had notably elevated serum β2-microglobulin and neopterin levels compared to HIV-negative controls without PrEP. Age-adjusted CSF NfL levels were comparable between MSM with HIV and MSM on PrEP but were higher than in the HIV-negative control group (without PrEP). Additionally, the recent syphilis infection was related to increased immune activation in both CSF and blood.   

Investigators concluded that immune activation and neuronal injury markers remained elevated in virologically suppressed MSM with HIV and those on PrEP compared to controls. 

Source: tandfonline.com/doi/full/10.1080/23744235.2025.2515157#abstract