Follicular dendritic cells in multicentric Castleman disease present human herpes virus type 8 (HHV8)-latent nuclear antigen 1 (LANA1) in a proportion of cases and is associated with an enhanced T-cell response.

Multicentric Castleman disease (MCD) is a rare human herpes virus type 8 (HHV8)-associated lymphoproliferative disorder that occurs more frequently in patients infected with human immunodeficiency virus (HIV). In tissue samples, HHV8-infected plasmablasts localise to the mantle zones of the lymphoid follicles. We revisited the immunohistological features in 25 lymph node (LN) and three spleen samples of MCD. In five (20%) LN and one (33%) spleen sample, HHV8 latent nuclear antigen 1 (LANA1) staining was also noted on the follicular dendritic cells (FDC). The HHV8-positive FDC subgroup of patients had significantly higher numbers of CD3-positive T cells infiltrating the follicles when compared to the HHV8-negative FDC subgroup (P = 0.047). Furthermore, the numbers of HHV8-positive plasmablasts and serum HHV8 viral copy numbers were lower among the HHV8-positive FDC subgroup when compared to the HHV8-negative FDC subgroup (not statistically significant). Our findings show, for the first time, possible 'presentation' of an HHV8 antigen by FDCs in MCD.