A 26-year-old male with Ph+ chronic myeloid leukemia, recipient of an HLA-compatible marrow from a matched unrelated donor, showed good platelet engraftment coupled with poor neutrophil recovery. On day +33 the presence of surface-bound anti-neutrophil antibodies was detected by immunofluorescence. At variance with previously reported cases, the WBC count improved without any specific treatment, and the test became negative on day +42.