Human immunodeficiency virus-associated cystic lymphoid hyperplasia: An immunohistochemical description

Background: Cystic lymphoid hyperplasia (CLH) describes benign salivary lymphoepithelial cysts with a strong link to human immunodeficiency virus (HIV) infection and acquired immunodeficiency syndrome (AIDS). The pathogenesis is related to ductal dilatation of entrapped salivary elements due to intranodal HIV-associated atypical lymphoid hyperplasia. Very little is known about the immunophenotypic profile of this entity. Aim: This study aims to describe the immunopathological features of a series of CLH cases in HIV-positive patients to clarify the etiopathogenesis. Materials and Methods: Paraffin-embedded tissue from 25 cases of parotid CLH in HIV seropositive patients was immunohistochemically analyzed with CD3, CD20, CD4, CD8, and p24 using standard procedures. Statistical Analysis: The data are mostly descriptive and were analyzed using EpiInfo (3.5.1) (CDC, Atlanta, USA); significant differences were analyzed using the Student's t-test and the Chi-square test with a statistical significance level of P < 0.05 being used. Results: Immunostaining showed a CD8:CD4 of similar to 1:1 except in selected cases with decreased CD4 and increased CD8 expression in the interfollicular (IF) areas. p24 staining revealed 100% specificity in HIV-associated CLH. Conclusion: The immunohistochemical description of CD20, CD3, CD4, and CD8 provides an understanding of CLH pathogenesis. CLH of parotid lymph nodes in confirmed HIV-positive patients with 100% specificity with HIV p24 antibody validates the strong association of CLH with HIV and AIDS. The CD4:CD8 ratio was similar to 1:1; however, increased CD8 expression within IF areas may indicate possible HIV-related CLH as compared to other cystic parotid lesions.