Evaluation of post-transplant cytopenias in children undergoing allogenic hematopoietic stem cell transplantation

Pediatric hematopoietic stem cell transplantation (HSCT) has been used with increasing frequency in the treatment of many malignant and non-malignant diseases for many years. One of the most important complications that increase the risk of morbidity and mortality after transplantation is secondary cytopenias. Many factors may play a role in etiology, such as sepsis, viral infections, graft-versus-host disease (GvHD), myelotoxic drugs, autoimmunity, conditioning regimen intensity, transplantation indication, stem cell source, and blood group incompatibility between recipient and donor. However, definition criteria, etiological factors, diagnosis and management of post-transplant cytopenias, especially in pediatric patients, are still controversial. Our study aims to determine the frequency and risk factors of secondary cytopenias developing after transplantation in pediatric patients who underwent allogeneic HSCT. Thus, it aims to develop recommendations regarding early diagnosis, treatment and follow-up for high risk patients. Pediatric patients (2 months-20 years) who underwent allogeneic HSCT in our unit between 2008 and 2023 were included in the study. Post-transplant cytopenia developed in 58 (19 %) of 301 patients. Anemia with concomitant thrombocytopenia was found to be the largest cytopenia group with 21 patients, followed by pancytopenia group with 18 patients. There are no patients with isolated neutropenia. In total, 23 patients (7%) had neutropenia (N+AN+TN+ATN), 50 patients (16%) had thrombocytopenia (T+AT+TN+ATN). Anemia (A+AT+AN+ATN) was detected in 47 patients (15%). History of blood transfusion before transplantation, history of immune cytopenia before transplantation, acute GvHD, post-HSCT CMV infection/disease, ganciclovir, tacrolimus, MMF, fludarabine, older patient and donor age were determined as risk factors for the development of post-transplant cytopenia. Donor type, ABO blood group compatibility between recipient and donor, and transplant indication had no effect on the development of post-transplant cytopenia. In conclusion, secondary cytopenias that develop after transplantation are complicated, multifactorial and serious complications. Therefore, more comprehensive diagnosis, treatment and follow-up schemes are needed.