Résumé : Seventy autologous peripheral blood stem cell transplants (APBSCT) performed in 61 cancer patients were retrospectively analyzed. Patients were heterogenous with regard to malignancy, conditioning regimens and use of growth factors after transplantation. Six patients developed a non-infectious fever, fluid retention and pulmonary interstitial infiltrates during the early phase of neutrophil recovery. Diarrhea was observed in four of these patients and cutaneous rash in three. The clinical condition improved spontaneously in one patient, and within 48 h after steroid therapy in four. One patient died from multiple organ failure. Age, sex (all patients were female; P = 0.07), and time to platelet recovery did not distinguish the six courses complicated by the hypothetical engraftment syndrome (ES) from the other 64 courses taken as controls. However, neutrophil recovery > 0.5 x 109/l occurred earlier (P = 0.01), and the neutrophil count increment during the early phase of recovery was steeper in ES patients (P = 0.003). ES was also associated with infusion of a high number of CD34+ progenitors (P = 0.03) and conditioning with busulfan (P = 0.03). Although all ES patients received G-CSF after transplantation, an association of ES with G-CSF use could not be demonstrated, possibly because of the small number of courses not supported by GCSF. However, in one patient, ES did not recur after a second transplant unsupported by growth factors. Our study supports the idea of an engraftment syndrome associated with an early and steep neutrophil recovery after APBSCT.