Expression of Epstein-Barr virus and granzyme B in cytologic smears of histiocytic necrotizing lymphadenitis

Histiocytic necrotizing lymphadenitis (HNL) is a non-neoplastic disease of the lymph nodes that is self-limiting in its clinical course. In this study, the expression of Epstein-Barr virus (EBV), granzyme B, and other phenotypic markers of HNL was investigated in fine needle-aspirated (FNA) cytologic smears obtained from 38 patients with HNL. The smear were subjected to immunohistochemical staining for granzyme B, CD3, CD4, CD8, CD20, and CD68 in addition to in-situ hybridization for EBV to determine whether marker expression could be correlated with disease pathogenesis. The mean age of 28 female and 10 male patients was 22.8 years. CD8-positive cytotoxic T cells were noted in 65.0% of the smears (13/20 cases), whereas CD4 and CD68 were rarely observed. Granzyme B reactivity was seen in lymphocytes, especially in apoptotic areas, and in histiocytes, with positive rates of 25.0% (9/36) and 11.1% (4/36), respectively. Most FNA smears showed immunoreactivity to both CD3 and CD20, with a predominance of CD3-positive cells. In-situ hybridization for EBV was positive in 22.9% (8/35) of the cases. The immunohistochemical staining and EBV in-situ hybridization results obtained in bleached FNA smears were similar to those in histologic sections. Overall, our results implicate that even though EBV positivity and granzyme B immunoreactivity are noted in HNL, they do not appear to have any apoptosis-associated role.