Post-transplant ring sideroblasts are common in haploidentical peripheral blood stem cell transplantation but not...

To determine the prevalence of erythroid dysplasia and ring sideroblasts (RS) after peripheral blood stem cell transplantation (PBSCT), stratified by transplant type, and to assess the association with SF3B1 mutations and event-free survival (EFS).

In a retrospective single-center study, 35 adult patients undergoing PBSCT (10 haploidentical, 25 HLA-identical/compatible) were compared to 10 controls without myeloid malignancy. Bone marrow smears collected ≥25 days post-transplant (median 82 days) were analyzed for erythroid dysplasia (≥10 %) and RS (≥5 %) using Modified Wright and Prussian blue stains. SF3B1 mutation status was assessed via NGS. EFS was calculated using Kaplan-Meier analysis; multivariate Cox regression evaluated the predictors of EFS.

Erythroid dysplasia was significantly more common in PBSCT recipients than controls (p=0.011), markedly so in haploidentical recipients (8/10, 80 %) vs. HLA-identical/compatible (8/25, 32 %) and controls (2/10, 20 %). RS ≥5 % occurred in 50 % of haploidentical PBSCT, 16 % of HLA-identical/compatible PBSCT, and 0 % of controls (p=0.015). However, no pathogenic SF3B1 mutations were detected. In multivariate analysis, only haploidentical transplant type (HR 10.2, p=0.016) and age (HR 1.11 per year, p=0.033), but not ring sideroblastosis or erythroid dysplasia, were independent predictors of EFS.

Erythroid dysplasia and RS are significantly more frequent after haploidentical PBSCT, yet in the absence of SF3B1 mutations and without independent prognostic significance, they likely represent reactive marrow changes rather than clonal disease. Transplant modality and patient age remain key determinants of post-transplant outcome.