Recovery of Circulating T-Follicular Helper Cells after Hematopoietic Stem Cell Transplantation

myeloma remains an incurable malignancy. Allogeneic hematopoietic cell transplantation (AHCT) though sought as a potential curative strategy, has not translated to improved overall survival (OS) owing to a high incidence of transplant related mortality. The objective of this study was to assess if monocyte and lymphocyte count recovery at day 100 had any prognostic value in this population. Methods: We performed a retrospective analysis of patients who underwent AHCT for multiple myeloma between 2002 and 2013 at a single institution. The primary endpoint of the study was day 100 peripheral blood absolute lymphocyte (ALC) and monocyte count (AMC) post-AHCT on overall survival (OS). Other patient, disease and transplant related factors were also evaluated. An ALC >1⁄4 500/mL and AMC >1⁄4300/mL were used as cut-offs based on published data. OS was defined from the time of transplantation to last followup or death due to any cause. OS estimates were determined using the Kaplan-Meier estimator. Cox proportional hazards model was used for multivariate analysis. Results: 78 patients underwent AHCT for MM at our institution. Patient, disease and transplant characteristics are reported in Table 1. Eight patients were excluded from the survival and multivariate analysis owing to death prior to day 100 or because of missing day 100 counts. On multivariate analysis, only day 100 AMC 1⁄4500/mL at day 100, while significant on univariate analysis, was not significant on multivariate analysis. Figure 1 shows the Kaplan-Meier survival figure for the cohort that achieved an AMC >1⁄4300 (blue) versus 1⁄4300/mL was associated with improved survival.