CD34+/CD3+ cells ratio in the peripheral blood stem cells product and graft-versus-host disease: Is there still room for improvement?

Allogeneic hematopoietic stem cell (allo-HSC) transplantation (allo-HSCT) is a therapy of choice for patients requiring total bone marrow replacement. One of the critical issues is optimizing the number of allo-HSCs for successful outcomes, measured by the engraftment time and the incidence/severity of graft versus host disease (GvHD). We evaluated engraftment time and GvHD in comparison to the composition of infused CD34+ immature HSCs and CD3+ T cells in all-HSCTs. The study evaluated 97 patients with allo-HSCT from matched related (group MRD; n = 40), matched unrelated (group MUD; n = 28), mismatched unrelated (group MMUD; n = 6), and haploidentical (group haplo; n = 23) donors. Overall, we did not observe any correlation between the total count of CD34+ allo-HSC and CD3+ T cells or the count of CD34+ and CD3+ calculated per kilogram of body weight (kg) on engraftment as well as GvHD symptoms in all studied groups. However, the CD34+/CD3+ ratio may provide valuable information in the process of a graft quality assessment in haploidentical allo-HCST for the choice of therapeutic options.