Background: People living with HIV are called immunological non-responders (INR) when their CD4+ T cell count is not restored to immunocompetent levels, despite successful viral suppression. INR have increased risk of progression to AIDS, non-AIDS related morbidity, and death. Impaired mucosal barrier function is a prevailing hypothesis for why INR among people with HIV (PWH) have persistently low CD4+ T cell counts. Objective: To understand the molecular mechanisms behind incomplete immune recovery in INR, we analysed gene regulation and protein expression in gut tissues from INR, immunological responders (IR), and healthy controls (HC).