Evaluation of risk for graft-versus-host disease in children who receive less than the full doses of mini-dose methotrexate for graft-versus-host disease prophylaxis in allogeneic hematopoietic stem cell transplantation

Haploidentical stem cell transplant with post-transplantation cyclophosphamide and mini-dose methotrexate in children

BACKGROUND

Haploidentical stem cell transplantation (haplo-SCT) is an option for patients without human leukocyte antigen-matched related or unrelated donor. Post-transplantation cyclophosphamide (PTCy) is an effective method of graft versus host disease (GVHD) prophylaxis and permits the use of T-cell replete grafts in settings were ex vivo manipulation is not feasible.

METHODS

A retrospective study among patients younger than 18 years, with a history of hematologic malignancies who underwent haplo-SCT between 2012 and 2016. All patients received a preparative regimen of fludarabine, busulfan, and 400 cGy total body irradiation or melphalan. Post-transplant GvHD prophylaxis consisted either of PTCy (50 mg/kg on Days + 3 and + 4) and cyclosporine (CSA) plus mycophenolate (MMF) (15 mg/kg/dose, thrice daily, per os), or mini-dose methotrexate (MTX; 5 mg/m² dose) on Days + 5, +7, +10, and + 15.

RESULTS

A total of 52 children were included, whose median age was 9 years (interquartile range, 4.9-14; range, 1.2-17 years), and 63% were males. The most common complications were cytomegalovirus reactivation (57%) and hemorrhagic cystitis (36%). The acute GVHD prophylaxis was PTCy, CSA, and mini-dose MTX in 42 (81%) patients, and 10 (19%) patients received PTCy, CSA, and MMF. The cumulative incidence of acute GvHD II-IV, acute GvHD III-IV, and chronic GvHD were 42%, 8.5%, and 19%, respectively. Grades I-IV acute GvHD occurred in 100% of the patients who received prophylaxis with CSA and MMF, and 62% who received CSA and mini-dose MTX (p = .055). The transplant-related mortality at 100 days was 18%. The 5-year overall and event-free survival were 59% and 57%, respectively.

CONCLUSIONS

Haplo-SCT with PT/Cy can be an available, safe, and feasible option for children with hematologic malignancies; meanwhile, the use of mini-dose of MTX was associated with lower rates of acute GVHD. However, our results require further support from prospective randomized studies to improve the efficacy of this prophylactic strategy.

Treatment and response of autoimmune cytopenia occurring after allogeneic hematopoietic cell transplantation in children

Background

Autoimmune cytopenia (AIC) is a rare complication of allogeneic hematopoietic cell transplantation (HCT). In this study, we reviewed the diagnosis, treatment and response to therapy for pediatric patients with post-HCT AIC at our institution.

Methods

Of the 292 allogeneic HCTs performed from January, 2011 to December, 2015 at the Department of Pediatrics, The Catholic University of Korea, seven were complicated by post-HCT AIC, resulting in an incidence of 2.4%.

Results

All seven patients with post-HCT AIC had received unrelated donor transplant. Six of seven patients had a major donor-recipient blood type mismatch. The subtypes of AIC were as follows: immune thrombocytopenia (ITP) 2, autoimmune hemolytic anemia (AIHA) 2, Evans syndrome 3. Median time from HCT to AIC diagnosis was 3.6 months. All but one patient responded to first line therapy of steroid±intravenous immunoglobulin (IVIG), but none achieved complete response (CR) with this treatment. After a median duration of treatment of 15.3 months, two patients with ITP achieved CR and five had partial response (PR) of AIC. Five patients were treated with rituximab, resulting in the following response: 2 CR, 2 PR, 1 no response (NR). Median time to response to rituximab was 26 days from first infusion. All patients are alive without event.

Conclusion

Post-HCT AIC is a rare complication that may not resolve despite prolonged therapy. Rapid initiation of second line agents including but not limited to B cell depleting treatment should be considered for those that fail to achieve CR with first line therapy.