Intraepithelial CD15 infiltration identifies high grade anal dysplasia in people with HIV

Abstract

ABSTRACTMen who have sex with men (MSM) with HIV are at high risk for squamous intraepithelial lesion (SIL) and anal cancer. The identification of local immunological mechanisms involved in the development of anal dysplasia could aid treatment and diagnostics. We performed a study of 111 anal biopsies obtained from 101 MSM with HIV, who participated in an anal screening program. In a test prospective cohort (N=54), in addition to histological examination, we assessed multiple immune subsets by flow cytometry. Selected molecules were further evaluated by immunohistochemistry in a validation retrospective cohort (N=47). Pathological samples were characterized by the presence of Resident Memory T cells with low expression of CD103 and by changes in the Natural Killer cell subsets, affecting residency and activation. Furthermore, potentially immune suppressive subsets, including CD15+CD16+mature neutrophils, gradually increased as the anal lesion progressed. Immunohistochemistry confirmed the association between the presence of CD15 in the epithelium and SIL diagnosis, with a sensitivity of 80% and specificity of 71% (AUC 0.762) for the correlation with high-grade SIL. A complex immunological environment with imbalanced proportions of resident effectors and immune suppressive subsets characterizes pathological samples. Neutrophil infiltration, determined by CD15 staining, may represent a valuable pathological marker associated with the grade of dysplasia.Abstract Figure