To determine correlation of CD3+ T cells infusion dose with Acute Graft Versus Host Disease (GVHD) in patients undergoing Allogeneic Hematopoietic Stem Cell Transplantation (HSCT).

Objective: To determine correlation of CD3 dose with Acute Graft Versus Host Disease (GVHD) in patients undergoing HSCT. Methodology: Prospective observational was conducted at Armed Forces Bone Marrow Transplant Center Rawalpindi, Pakistan, from Feb 2021 to October 2022. Total n=124 patients were enrolled. All patients were followed for 100 days post allogenic stem cell transplant. Quantitative variables, such as recipient's and donor's age, Total nucleated cells, CD3+ T cells and CD34 dose. Qualitative variables, including the recipient's and donor's age, gender, gender mismatches, underlying disease, type of transplant, source of graft, CMV infection, type of GVHD prophylaxis, incidence of stage and grade of GVHD . Results: Median age was 10years. Eighty patients were male and n=40 were females. The primary source of graft was bone marrow harvest (81.3%) followed by a combination of bone BMH and peripheral blood stem cells (16.9%), and only (PBSC) (1.6%). Median dose of TNC was 5.10, CD34 dose 4.07 and CD3+ T cells dose was 3.7. Twenty six (21%). patients developed acute graft versus host disease. Grade II in 61.8 %, grade III in 30.8 %while grade IV in 7.7% patients. Those patients with TNC dose ?8x108/kg had frequent aGVHD which showed a statistical significance. CD34 and CD3 cells dose didn’t show any statistically significant correlation with development of aGVHD.Eight (6.4%) patients died in our study. OS was 93.5% and DFS was 91.6% with GRFS of 78.7%. Conclusion: Our findings suggest that CD3+ T cell dose may not be an independent predictor of aGVHD in our patient population where donors are sibling donors in majority of cases. Further larger-scale studies are required to provide a more comprehensive understanding of the role of CD3+ T cells dose and other intricate factors influencing development of aGVHD in allogeneic HSCT in our population.