High infiltration of CD20+ B lymphocytes in extranodal natural killer/T-cell lymphoma is associated with better prognosis.

Immune cells have an uncertain function during the progression of extranodal natural killer/T-cell lymphoma (ENKTL). The present study determined the distribution, phenotype, and clinical significance of B lymphocytes in ENKTL. Immunohistochemistry indicated high infiltration of CD20+ B lymphocytes in the tumour tissues of 40% of the patients, and that a high infiltration correlated with better overall survival. Moreover, B lymphocytes had an active mature phenotype in situ and suppressed the proliferation of ENKTL cells in vitro. These results suggest that tumour infiltration of CD20+ B lymphocytes may be a new prognostic indicator for patients with ENKTL.