Pulmonary manifestations during neutrophil engraftment in recipients of allogeneic hematopoietic cell transplantation for myelofibrosis

Allogeneic hematopoietic cell transplantation (alloHCT) remains the only potentially curative treatment for both primary and secondary myelofibrosis (MF). However, outcomes are often complicated by the presence of cardiopulmonary comorbidities common in this patient population, contributing to elevated non-relapse mortality (NRM). In this study, we characterize a distinct clinical entity—pulmonary manifestations during neutrophil engraftment—marked by pulmonary infiltrates and respiratory compromise in patients undergoing alloHCT for MF. Eighteen of 83 patients (22%) developed these pulmonary complications, with radiologic findings including ground-glass opacities, consolidations, and pulmonary nodules. Notably, only one-third of these patients exhibited additional features typically associated with classical engraftment syndrome. Pulmonary arterial hypertension (PAH) was significantly associated with the development of these complications (odds ratio 3.68; 95% CI: 1.13–12; P = 0.04), whereas no correlation was found with pre-transplant pulmonary function testing or imaging. Hypoxemia was observed in 15 of the 18 affected patients. Despite the severity—44% requiring intensive care and 40% necessitating mechanical ventilation—all patients responded favorably to corticosteroids and supportive care. Importantly, the presence of pulmonary complications during engraftment did not negatively affect overall survival or NRM.