High Tumour Plasma Cell Infiltration Reflects an Important Microenvironmental Component in Classic Hodgkin Lymphoma Linked to Presence of B-symptoms

Plasma cells are important prognostic actors in different malignancies. The tumour microenvironmental composition in classic Hodgkin lymphoma (cHL) is a major prognostic key element; however, clinicopathological studies regarding plasma cells in cHL are lacking. The aim of this study was to investigate CD138+ (also termed SDC1+) plasma cell and IgG4 producing (IgG4+) plasma cells infiltration in the microenvironment of cHL. Immunohistochemistry with anti-CD138 and IgG4 antibodies was performed on diagnostic tumour biopsies from 124 patients with cHL, on tissue micro array (TMA). In 120 cases, CD138+ plasma cell-infiltration was associated with the presence of B-symptoms (P = 0·028) and advanced stage, IIB-IVB (P = 0·009). In multivariate analysis, CD138+ plasma cells correlated with eosinophil infiltration (P = 0·013). The subgroup of IgG4+ plasma cells was analysed in 122 cases and only correlated to CD138+ plasma cells (P = 0·004). Patients with high proportion of tumour infiltrating CD138+ plasma cells (defined as ≥10%), had a more inferior event-free survival (P = 0·007) and overall survival (P = 0·004) than patients with a low proportion of infiltrating CD138+ plasma cells (<10%), although significance was not maintained in multivariate analysis. In summary, a high proportion of tumour-associated plasma cells in cHL reflect an important component in the microenvironment of cHL.