Increased incidence of neurological complications in patients receiving an allogenic bone marrow transplantation from alternative donors

OBJECTIVE To compare the frequency and type of neurological complications after bone marrow transplantation (BMT) with an HLA identical unrelated donor or a mismatched related donor (alternative donors) to the neurological complications after matched sibling BMT for standard and high risk leukaemia or myelodysplastic syndromes. METHODS Retrospective analysis of consecutively treated patients with (a) BMT from alternative donors (n=39), (b) treated with matched sibling BMT for standard risk leukaemia, myelodysplastic syndromes, or aplastic anaemia (n=53), and (c) treated with matched sibling BMT for high risk leukaemia, myelodysplastic syndromes, or aplastic anaemia (n=49). RESULTS A total of 72 neurological complications were found. Most of these occurred within the first 6 months after transplant. Thirty six patients developed a severe neurological complication: 17 Alternative donor patients (44%) by contrast with six standard risk patients (11%) and 13 high risk patients (27%; p<0.005). The most frequent complication was a metabolic encephalopathy occurring in 18% of patients. Most of the encephalopathies were caused by either the transplant procedure, cyclosporin, systemic infections, microangiopathic thrombopathy, or by complications induced by graft versus host disease. Infections of the CNS developed in 9% of patients, cerebrovascular lesions in 3%. CONCLUSIONS Severe neurological complications are more frequent after BMT from alternative donors. This is mainly due to increased treatment related morbidity and to more profound immunosuppression after BMT from alternative donors.