Absolute lymphocyte count prior to rituximab therapy predicts time to progression in patients with follicular grade 1 lymphoma

7586 Background: The immunologic mechanisms of action of rituximab have been described as complement mediated lysis, vaccine like effect, antibody-dependent cellular cytotoxicity (ADCC) and the cellular microenvironment. We hypothesized that in the treatment of follicular grade 1 lymphoma (FL), the presence of a stronger host immune status prior to rituximab therapy would result in a prolonged time to progression (TTP). As a surrogate marker for immune status, we evaluated the absolute lymphocyte count (ALC) prior to rituximab treatment. Methods: Between 1996 and 2002, 1,104 consecutive FL patients were evaluated at Mayo Clinic Rochester. Of these patients, we retrospectively analyzed a group of all FL patients who received rituximab (375 mg/m2 once a week for four weeks) alone at any time during their lymphoma treatment at the Mayo Clinic (n=79). The primary end-point was to assess the impact of ALC just prior to rituximab therapy on TTP for FL. Results: The median age of the cohort was 56.6 years (range...