Prediction of Outcome in Diffuse Large Cell Lymphoma by the Major Histocompatibility Complex Class II (HLA-DR, DP, DQ) and Class I (HLA-A, B, C) Phenotype.

Ninety-nine consecutive diffuse large cell lymphoma (DLCL) patients were studied by immunohistochemistry to determine whether clinical outcome was predicted by major histocompatibility complex (MHC) antigen phenotypic expression. Statistically significantly shorter disease free survival (p = 0.005), but not overall survival (p = 0.47), was observed when patient lymphomas failed to express class I MHC antigens. We also observed significantly reduced survival of class II MHC HLA-DP negative patients (p = 0.038). This extends our previous finding of poor outcome with absent class II MHC HLA-DR in DLCL(1) to other MHC antigens and demonstrates that the phenomenon of defective class II antigen expression comprises 16% of these DLCL patients. Known clinical parameters predictive of prognosis were equally distributed between phenotypic groups. These findings indicate that aberrancy of immune phenotype in DLCL is critical to patient outcome and we speculate that loss of MHC expression may confound host immunosurveillance and tumor containment.