Splenic irradiation before hematopoietic stem cell transplantation for chronic myeloid leukemia: long-term follow-up of a prospective randomized study

Successful haploidentical hematopoietic stem cell transplantation (HSCT) and durable engraftment by repeated donor lymphocyte infusions for a Chinese patient with transfusion-dependent hemoglobin (Hb) Hammersmith and massive splenomegaly

BACKGROUND

Hemoglobin (Hb) Hammersmith is a rare form of unstable β-chain hemoglobinopathy causing hemolytic anemia. This rare event led to a more serious transfusion-dependent phenotype in a patient. It was successfully cured by haploidentical hematopoietic stem cell transplantation (HSCT).

METHODS AND RESULTS

A 9-year-old mainland Chinese male with a history of neonatal unconjugated hyperbilirubinemia was diagnosed to have hemoglobin (Hb) Hammersmith. He required regular blood transfusion but was unable to be transfused to desired parameters for 8 years prior to transplant due to social and geographical reasons. He subsequently developed marrow hyperplasia and progressive splenomegaly (down to umbilicus level), suggestive of extramedullary hematopoiesis. Eventually, the family came to Hong Kong and complied to a more intensive transfusion regimen and preconditioning chemotherapy 3 months prior to transplant. He underwent haploidentical HSCT using paternal TCRαβ/CD45RA-depleted graft but suffered from graft rejection, despite splenic irradiation for massive splenomegaly. It was successfully salvaged with second HSCT with unmanipulated graft from the same donor with additional serotherapy and donor lymphocyte infusions.

CONCLUSION

Allogenic haploidentical HSCT for hemoglobin Hammersmith is feasible but adequate immunosuppression during conditioning is crucial. Precise adoptive cell therapy can promote durable engraftment.

Splenomegaly May Increase the Risk of Rejection in Low-Risk Matched Related Donor Transplant for Thalassemia, This Risk Can Be Partially Overcome by Additional Immunosuppression during Conditioning

Severe thalassemia syndromes (ST) are highly curable by bone marrow transplant (BMT), but rejection may still occur. We retrospectively analyzed our fully matched related donor transplants to establish if isolated splenomegaly is an independent risk factor for rejection and if this risk can be reduced by modifying the conditioning protocol. In this study, we compared rejection rates between patients with and without splenomegaly in 189 consecutive low-risk ST transplants across 2 sequential conditioning regimens: regimen A (August 2013 to December 2016): busulfan (14 mg/kg oral, not adjusted to serum levels), cyclophosphamide (200 mg/kg), and anti-thymocyte globulin (ATG) (Genzyme (Sanofi, Paris, France) 4 mg/kg or Fresenius (Grafalon, Neovii Biotech GmbH, Gräfelfing Germany) 16 mg/kg on days -12 to -10), and regimen B: same backbone as regimen A except fludarabine total dose of 150 mg was added upfront and ATG dose was increased to 7 mg/kg in case of splenomegaly and/or sex-mismatched transplants (January 2017 to September 2018). Compared with regimen A, in regimen B, both overall rejection rates (RRs) (16% versus 6.5%, P = .023) and treatment-related mortality (TRM) (9.9% versus 2.8%, P = .038) improved significantly. By Cox regression analysis, the improvement in RR between the 2 protocols was particularly significant in patients with splenomegaly (RR 54.5% versus 6.5%, P = .00015; TRM 18.2% versus 6.5%, P = .25) (hazard ratio, 4.13; confidence interval, 1.61 to 10.6; P = .003). The increased risk of rejection related to splenomegaly can be overcome by adding fludarabine to the standard ATG-Busulfan- Cyclophosphamide (ATG-Bu-Cy) protocol without significantly increasing transplant-related morbidity and mortality or resorting to splenectomy pre-BMT.

Splenectomy in Myelofibrosis: Indications, Efficacy, and Complications

Splenomegaly, which may range from a few centimeters below the left costal border to massive dimensions, is one of the most characteristic features in patients with advanced myelofibrosis (MF). Splenectomy may offer an effective therapeutic option for treating massive splenomegaly in patients with MF, and especially in cases of disease refractory to conventional drugs, but it is associated with a number of complications as well as substantial morbidity and mortality. Whether splenectomy should be performed before allogeneic hematopoietic stem-cell transplantation is also controversial, and there is a lack of prospective randomized clinical trials that assess the role of splenectomy before hematopoietic stem-cell transplantation in patients with MF. Although splenectomy is not routinely performed before transplantation, it may be appropriate in patients with massive splenomegaly and related symptoms, so long as the higher risk of graft failure in such cases is taken into account. This review aims to describe the efficacy, indications, and complications of splenectomy in patients with MF; and to evaluate the long-term impact of splenectomy on patient survival and risk of disease transformation.

Splenic irradiation before allogeneic stem cell transplantation for myelofibrosis

Splenectomy before allogeneic stem cell transplantation (ASCT) for patients with myelofibrosis (MF) remains a matter of debate, and conflicting results have been reported to date. The procedure seems to fasten post-transplant hematological recovery, but it does not have an impact on survival. The role of pre-transplant splenic irradiation (SI) is much more difficult to evaluate. Forty-four patients (25 males and 19 females) with MF at median age of 49 years at diagnosis (range 14-67) underwent ASCT. The post-transplant outcome was compared between irradiated and non-irradiated patients. Eleven patients received irradiation before transplantation. Median dose of radiation was 1000 cGy (range 600-2400). There was no difference in median time to engraftment between patients with and without previous radiotherapy. Acute and chronic graft versus host disease (GVHD) occurred in 47% and 36% of patients, respectively. There was no difference in GVHD incidence between groups. Eight patients relapsed/progressed in irradiated group versus 17 in non-irradiated (70% vs. 51%; p = 0.3). Transformation to acute myeloid leukemia was observed in 3 patients: 2 in irradiated and 1 in non-irradiated group. In total, 22 patients died with no statistical difference in death rate between irradiated and non-irradiated subjects. The probability of overall survival after transplant for the entire cohort at 2 years was 54% (72% for irradiated and 48% for non-irradiated patients; p = 0.25). Splenic irradiation prior to ASCT for myelofibrosis has not beneficial effect on post-transplant outcome.