Poor platelet engraftment combined with persistent pulmonary infection after haploidentical allogeneic hematopoietic stem cell transplantation: a case report.

Poor graft function (PGF) with persistent thrombocytopenia is a serious post-transplant complication linked to increased mortality. Active infections can worsen outcomes. We report a case of secondary poor platelet engraftment with refractory pulmonary infection after haploidentical HSCT. A 52-year-old woman developed Rhizopus microsporus infection on day +1. Neutrophil engraftment occurred by day +13, but platelet engraftment was delayed until day +40. She later developed Pseudomonas aeruginosa septic shock (day +106) and multidrug-resistant Klebsiella pneumoniae superinfection (day +190). Thrombopoietin receptor agonists showed minimal response, and she died 6 months post-transplant. This case highlights ultra-early mucormycosis, TPO-RA failure during active infection, and a fungal-bacterial cascade, underscoring the need for infection control before PGF-directed therapy.