Purpose: Tumor-associated macrophage (TAM) content predicts survival in follicular lymphoma (FL) patients treated with chemotherapy. The aim of this study was to determine how combination of rituximab with chemotherapy influences TAM-associated clinical outcome.

Experimental Design: Expression of a macrophage marker, CD68, was determined immunohistochemically from FL samples of 96 patients treated with rituximab and cyclophosphamide-Adriamycin-vincristine-prednisone regimen. Of them, 71 received therapy at diagnosis and 25 at relapse. Neutrophil and CD3+ lymphocyte counts were also measured. The median follow-up time for the cohort was 54 months. Fourty-five patients previously treated with chemotherapy served as a control group.

Results: Consistent with previous studies, high TAM amount was associated with adverse outcome in chemotherapy-treated patients (P = 0.026). In contrast, after rituximab and cyclophosphamide-doxorubicin-vincristine-prednisone regimen, high TAM content correlated with longer survival rates. According to Kaplan Meier estimates, the median progression free survival (PFS) was not reached for patients with high TAM content compared with 45 months for patients with low TAM scores (P = 0.006). A trend toward a better overall survival (OS) at 5 years was also observed for patients with high TAM content (OS, 97% versus 90%, P = 0.116). The positive prognostic value of TAMs was seen both for the patients treated at diagnosis and at relapse. In multivariate analyses, TAM content remained an independent prognostic factor for OS and PFS. Neutrophil and CD3+ lymphocyte counts did not correlate with outcome.

Conclusions: The data suggest that high TAM score is associated with a favorable prognosis in FL patients treated with immunochemotherapy.