The Impact of CD34+ Cell and Immunefector Cell Dose on Transplant Outcomes

Introduction: The impact of the graft content after mobilizing blood for hematopoetic stem cell transplantation is not well known unless manipulaton is done. The aims of this study are to evaluate the impact of the graft content from different donor sources and to evaluate whether graft content can have different impact on different types of diseases

Patients& Methods: Between 2010-2019, 198 allogeneic hematopoeitic stem cell recipients were retrospectively evaluated. Patients characteristics and graft content including CD34 + hematopoietic stem cell, CD3+ T cell, CD19 +B cell and CD56 +NK cells are shown in the table. Transplanted CD34 cell dosage per body weight was categorized into three : > 3-4,9 x 10⁶ /kg, >5-6,x 10⁶ and >7x 10⁶ CD34⁺/kg The medication for the GVHD prophylaxis and its effect on transplant otcome via lyhmpcyte dosage was evaluted.

Results: The baseline characteristics of ASCT patients are shown in Table 1. Median CD34⁺ cell, CD3⁺ lymphocyte, CD19⁺ lymphocyte and NK doses were 6,12 x 106/kg (0,4-10,26), 2,42 x 108/kg (0,34-30,7), 0,59 x 108/kg (0-8,66) and 0,27 x108/kg (0,04-14,5) respectively. According to the type of donor, no differences were seen between CD34 (p=0.095) and other immunogenic CD3, CD19, CD56 cell counts (p>0,05). For subsequent analysis, the cases were grouped into 3 categories according to the CD34+ cell doses. There was no significant association between the CD34+ cell dose and aGVHD (grade II-IV or III-IV). In addition, we evaluated a possibility that the protective effect of CD34+ cell dose on relapse may be immune mediated. However there was no significant association between infused CD34+ cell dose and relapse.

Conlusion: Eventhough there are few reports related to CD34 cell count and improvement in overall survival in MRD and MUD recipients, our results did not show any impact of different CD34 dosages on overall survival, GVHD, relaps, engraftment Besides T, B and NK lymphocyte dosage in the graft did not have impact on transplantation as well. Eventhough the graft content was similiar the lymhoid diseases had decreased OS than myeloid diseases.

Özcan:Bayer: Research Funding; Abbvie: Other: Travel expenses/accommodations, Research Funding; Janssen: Research Funding; Acerta: Research Funding; Reddy's: Research Funding; MSD: Research Funding; Roche: Other: Travel expenses/accommodations, Research Funding; Takeda: Research Funding; Pfizer: Research Funding; Jazz: Other: Travel expenses/accommodations. Beksac:Sanofi: Research Funding, Speakers Bureau; Celgene: Speakers Bureau; Amgen: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Janssen: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Takeda: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Oncopeptides: Membership on an entity's Board of Directors or advisory committees.