Systemic inflammatory autoimmune disease before allogeneic hematopoietic stem cell transplantation is a risk factor for death in patients with myelodysplastic syndrome or chronic myelomonocytic leukemia.

Myelodysplastic syndrome (MDS) is well known to be complicated by systemic inflammatory autoimmune disease (SIADs). However, it remains unclear how the prognosis after allogenic hematopoietic stem cell transplantation (allo-HSCT) in patients with MDS is impacted by SIADs that occur before allo-HSCT. Therefore, we hypothesized that SIADs before allo-HSCT may be a risk factor for negative outcomes after allo-HSCT in patients with MDS. We conducted a single-center, retrospective, observational study of sixty-nine patients with MDS or chronic myelomonocytic leukemia who underwent their first allo-HCT. Fourteen of the patients had SIADs before allo-HSCT. In multivariate analysis, the presence of SIADs before allo-HSCT was an independent risk factor for overall survival (HR, 3.36, 95% confidence interval: 1.34-8.42, p = 0.009). Endothelial dysfunction syndrome was identified in five of 14 patients with SIADs who required immunosuppressive therapy or intensive chemotherapy, and notably, all patients with uncontrollable SIADs at allo-HSCT developed serious endothelial dysfunction syndrome and died in the early phase after allo-HSCT. The development of SIADs in the context of MDS is thought to reflect the degree of dysfunction of hematopoietic cells in MDS and suggests a higher risk of disease progression. In addition, MDS patients with SIADs before allo-HSCT are considered to be at higher risk of endothelial dysfunction syndrome because of preexisting vascular endothelial dysfunction due to SIADs. In conclusion, SIADs before allo-HSCT constitute an independent risk factor for death in MDS patients undergoing allo-HSCT.