Extrafollicular PD1 and Intrafollicular CD3 Expression Are Associated With Survival in Follicular Lymphoma.

Both microenvironment and tumor biomarkers impact outcome in follicular lymphoma (FL). We aimed to study the effect of Ki-67, CD3, CD68, and PD1 expression on outcome of FL.Forty-eight patients were included. Stained slides were visually assessed and marker expression was correlated with outcome. Both intra- and extrafollicular expression of Ki-67, CD68, and PD1 were evaluated. CD3 was evaluated only in the intrafollicular area. The median values of expression served as a cutoff point for low- and high-expression groups.High extrafollicular PD1 expression predicted superior FFTF (freedom from treatment failure) compared with low expression (5-year 52% vs. 44%, P = .04). Five-year FFTF markedly increased from 37% to 67% (P = .057) in patients with low intrafollicular CD3 expression.Our study supports the hypothesis that survival in FL depends on the immunologic cross talk between malignant cells and microenvironment; however, the specific types of cells that influence the clinical behavior of FL are still unknown.