Dear Sir,The most common toxicities for autologous stem cell transplantation (ASCT) in multiple myeloma (MM) are gastrointestinal and mucositis. Mortality is lower than 5% in well-selected patients. Engraftment syndrome (ES) is a common complication of ASCT, whereas transplant-associated thrombotic microangiopathy (TA-TMA) and hemophagocytic syndrome (HPS) are very rare, mostly occurring after allogeneic transplants, and often have a fulminant course. We describe a case of MM where the post-ASCT course was marked by ES, life-threatening TA-TMA and secondary HPS occurring concomitantly.A 55-year-old lady with MM stage IIIA received six cycles of induction chemotherapy with cyclophosphamide, bortezomib and dexamethasone (Reeder et al., 2010) and had very good partial response. In March 2017, she underwent ASCT by peripheral blood stem cell harvest performed using granulocyte-colony stimulating factor (G-CSF) mobilisation. CD34 was 2.01 × 10 6 kg −1 . Melphalan was given at 200 mg m −2 on D−1.G-CSF 5 μg kg −1 was started from D+1. Antibiotics were added on D+2 for febrile neutropenia and changed to meropenem, linezolid and liposomal amphotericin B for recurrent fever on D+8. Work-up for infection was negative. She developed grade 2 mucositis and diarrhoea. Neutrophil engrafted on D+10, and the platelet count was 20 × 10 9 L −1 with support. On D+11, fever recurred, with worsening of diarrhoea, weight gain (4% of baseline), mild dyspnoea, no skin rashes, new chest infiltrates and elevated creatinine and bilirubin over the next 48 h. Repeat work-up for infection was negative. ES was diagnosed, and G-CSF was discontinued. Diuretics and steroids (prednisone-1 mg kg −1 day −1 for 5 days) were initiated, colistin was added, and supportive treatment continued, to which she showed initial response. From D+17 to D+21, she deteriorated with recurring high fever, worsening diarrhoea, dyspnoea, tachypnoea, tachycardia, mild hypertension initially, mild gum/oral bleeding, persistent thrombocytopenia even with support, declining leucocyte count, anaemia, rising bilirubin and an episode of haemoptysis, haematuria and hypotension on D+21. Inotropes were initiated with the continuation of antibiotics and antifungals (liposomal amphotericin B), and steroids were restarted. Non-invasive ventilator (NIV) support was required