Continuous Mononuclear Cell Collection (cMNC) protocol impact on hematopoietic stem cell collections in donors with negative collection predictors

Background: Recently, novel protocol utilizing Continuous Mononuclear Cell Collection (cMNC) have been introduced for leukapheresis. We compared the efficacy of cMNC with an older protocol - mononuclear cell collection (MNC) for CD34+ cell collection in unrelated donors with negative stem cell collection predictors.

Material and methods: Retrospective data from a series of 258 consecutive unrelated hematopoietic stem cell donors was included in this single-center study (80 donors collected with cMNC and 178 with MNC). The donors with poor predictors for collection such as low number of circulating CD34+ cells and/or weight disproportion were assigned to the cMNC arm.

Results: The cMNC protocol yielded a higher number of CD34 + cells per donor body weight (7.63 × 10⁶/kg vs 6.82 × 10⁶/kg, p = 0.027). One apheresis was sufficient for collection of target cell number in 89% individuals from both groups despite negative predictors in the cMNC group. In donors with CD34 + cell count <100/μL and a body weight disproportion between donor and recipient one apheresis was sufficient in 83% of donors in cMNC group and in 58% in MNC group (p = 0.0345) with collection efficiency CE2% values of 61% for cMNC and 62% for MNC (p = 0.77).

Conclusion: cMNC protocol is more efficient in donors with low pre-apheresis CD34+ cell count and weight disproportion between donor and recipient. This suggests that the use of cMNC in unrelated donors could possibly further improve the results of HSC collections.