Follicular dendritic cells display microvesicle-associated LMP1 in reactive germinal centers of EBV+ classic Hodgkin lymphoma

We describe for the first time the presence of LMP1 protein in EBV-encoded RNA (EBER)-negative follicular dendritic cells (FDCs) of reactive germinal centers (GC) associated with EBV+ cHL. Presence of LMP1+ GCs was independ ent of geographic region and age of patients. Variable numbers of reactive GCs were present in 22.2% of cases (34 of 153), whereas LMP1 staining of FDCs was present in about a third of cases (10 of 34) with reactive GC. Most cases with LMP1+ GC were mixed-cellularity (MC) subtype, but some nodular s clerosis (NS) was also present. GC cells with LMP1+ FDCs were surrounded by numerous EBV-infected cells which were positive for EBER, LMP1, and CD30. Double immunolocalization analysis revealed that LMP1 was associated with CD63, an exosomal marker, and with CD21. The possibility is discussed that p eri-follicular EBV-infected cells release LMP1 protein, perhaps through exosomes, and that the protein is then captured by FDCs and is presented to EBER-negative GC B cells.
Source: Virchows Archiv - Category: Pathology Source Type: research