Engraftment Kinetics and Early Clinical Outcomes Following Hematopoietic Stem Cell Transplantation: A Prospective Observational Study from a Tertiary Care Hospital in Uttarakhand.

BACKGROUND: Hematopoietic stem cell transplantation (HSCT) is an established treatment for several malignant and non-malignant hematological disorders. The timing and success of hematopoietic engraftment are important early indicators of transplant recovery. OBJECTIVE: To describe neutrophil and platelet engraftment kinetics after HSCT and to explore associations of engraftment with patient characteristics, transplant compatibility, graft characteristics, transfusion requirements, and early recorded survival status. METHODS: This prospective observational study included 45 consecutive patients undergoing autologous or allogeneic HSCT at a tertiary-care transplant centre in Dehradun, India. Engraftment was defined using predefined neutrophil and platelet count criteria. Patient, transplant, compatibility, graft-quality, transfusion, and early follow-up variables were extracted from the master clinical dataset. Continuous variables were compared using the two-sided Mann-Whitney U test and categorical variables using Fisher's exact test. RESULTS: Successful hematopoietic engraftment occurred in 40/45 patients (88.9%). Mean neutrophil and platelet engraftment occurred at 13.47 ± 2.99 days and 15.53 ± 4.73 days, respectively. Pre-transplant peripheral-blood CD34+ count was lower in the engraftment group but was not statistically significant (37.15 ± 37.41 vs 83.59 ± 68.11; P=0.148). Final infused CD34+ cell dose was also not significantly different (9.15 ± 4.95 vs 8.60 ± 5.66 ×10⁶/kg; P=0.732). ABO compatibility was not significantly associated with engraftment (32/35 vs 8/10; P=0.306; OR 2.67, 95% CI 0.38-18.74). Product viability was lower in the engraftment group (96.34 ± 2.94% vs 98.69 ± 0.92%; P=0.045), although this finding should be interpreted cautiously given the small number of non-engraftment events and multiple comparisons. Three deaths occurred, all among patients with non-engraftment. CONCLUSION: In this heterogeneous single-centre cohort, most patients achieved hematopoietic engraftment within the first three weeks after HSCT. Neither pre-transplant circulating CD34+ count, final infused CD34+ dose, nor ABO compatibility showed a statistically significant association with engraftment. The small sample size and only five non-engraftment events limit causal inference and multivariable analysis. Larger prospective cohorts with longitudinal donor-chimerism and time-to-event data are required.