Human leukocyte antigen-DR expression on flow cytometry and tumor-associated macrophages in diffuse large B-cell lymphoma treated by rituximab, cyclophosphamide, doxorubicin, vincristine and prednisone therapy: retrospective cohort study.

Loss of human leukocyte antigen (HLA)-DR expression may be related to a poor prognosis of diffuse large B-cell lymphoma (DLBCL), and tumor-associated macrophages (TAMs) may influence tumor progression. We retrospectively reviewed 36 patients with newly diagnosed DLBCL who received R-CHOP (rituximab, cyclophosphamide, doxorubicin, vincristine and prednisone) therapy at Kanagawa Cancer Center in Japan from 2004 to 2010. HLA-DR expression by lymphoma cells was evaluated using flow cytometry, and TAMs in lymphoma tissue were detected by immunohistochemistry for CD68 as a marker of macrophages and CD163 as a marker of M2 TAMs. Three-year overall survival was, respectively, 100% versus 69.6% in the HLA-DR "bright" and "not bright" groups (p = 0.012). Patients from the HLA-DR "not bright" group with strong CD163 expression had a much worse prognosis than other patients. The HLA-DR status shown by flow cytometry can be used to predict the prognosis of patients with DLBCL receiving R-CHOP therapy and prognostic accuracy can be increased by also assessing TAMs.