Early lymphocyte recovery predicts superior survival after autologous hematopoietic stem cell transplantation for patients with primary systemic amyloidosis

Purpose: Absolute lymphocyte count recovery at day 15 (ALC-15) post-autologous stem cell transplantation (ASCT) is a powerful prognostic indicator for survival for multiple hematologic malignancies and metastatic breast cancer. The relationship of ALC-15 with clinical outcomes in primary systemic amyloidosis is unknown. Experimental Design: We evaluated 145 consecutive patients with primary systemic amyloidosis who underwent ASCT at the Mayo Clinic from 1996 to 2003. The ALC-15 threshold was set at 500 cells/μL based on our previous observations. Results: The median patient follow-up was 22 months (range, 3-87 months). Higher hematologic complete response was observed in patients with an ALC-15 ≥ 500 cells/μL compared with patients with an ALC-15 < 500 cells/μL (41% versus 21%, P < 0.0008, respectively). The median overall survival and progression-free survival times were significantly better for the 59 patients that achieved an ALC-15 ≥ 500 cells/μL compared with 86 patients with ALC-15 < 500 cells/μL (not reached versus 53 months, P < 0.0003 and not reached versus 27 months, P < 0.0001, respectively). Multivariate analysis showed ALC-15 to be an independent prognostic factor for overall survival and progression-free survival. Conclusions: ALC-15 ≥ 500 cells/μL is associated with significantly improved clinical outcomes following ASCT in patients with primary systemic amyloidosis.