Hyperplastic lymph node from an HIV-infected person with persistent generalized lymphadenopathy (PGL). (A) Two-color staining. Within a follicle numerous germinal center (GC) cells exhibit nuclear staining (blue) for BCL-6. In the same follicle, large cells with a plasma cell morphology show a strong cytoplasmic and membrane staining (reddish) with the anti-CD138/syndecan-1 MoAb. They are present within the GC and in the perifollicular (PF) zone. No co-expression of both markers by the same GC cell is detectable. Paraffin-embedded tissue section, no counterstain. (B) EBER in situ hybridization. EBER⁺ cells are localized around the hyperplastic follicle (right) and within the expanded germinal center (left). Paraffin-embedded tissue section, nuclear fast red counterstain. (C) Immunostaining for LMP-1. No LMP-1 expression by lymph node cells is detectable. Paraffin-embedded tissue section, APAAP method, hematoxylin counterstain. Original magnification ×250 (A), ×100 (B) and (C).