Histopathological analysis and demonstration of EBV and HIV p-24 antigen but not CMV expression in labial minor salivary glands of HIV patients affected by diffuse infiltrative lymphocytosis syndrome

BACKGROUND: The diffuse infiltrative lymphocytosis syndrome (DILS) in HIV patients is characterized by the persistence of CD8-circulating lymphocytes and lymphocytic infiltration, predominantly in salivary glands. METHODS: We examined seven HIV-positive patients with bilateral parotid enlargement and sicca symptoms. Minor labial salivary gland biopsies were performed in all patients and submitted for histopathological analysis and immunohistochemistry for CD4, CD8, cytomegalovirus (CMV), LMP-EBV protein, and HIV p-24 protein. RESULTS: In all cases, lymphocytic infiltration of the minor salivary glands, mainly periductal, was found. Acinar atrophy, ductal ectasia, and mild to moderate fibrosis were also observed. We noticed strong immunohistochemical reaction for LMP-EBV and p-24 proteins in ductal cells in all cases, while staining for CMV was consistently negative. The lymphocytes were positive for CD8, but consistently negative for CD4. CONCLUSIONS: A role of Epstein-Barr virus (EBV) and HIV, but not CMV, in the pathogenesis of DILS, is suggested by our immunohistochemical findings.