Coincidence of severe aplastic anaemia with multiple sclerosis or thyroid disorders. Report of 5 cases.

Five patients with severe aplastic anaemia (SAA) who, simultaneously (n = 3) or consecutively (n = 2), presented with multiple sclerosis (MS) (n = 2) or immune hyperthyroidism (IHT) (n = 2) or subacute thyroiditis (n = 1) are described. Two female patients with MS developed SAA after a small dose of azathioprine. Another patient simultaneously presented with IHT and SAA. SAA and MS responded to cyclosporine while IHT required 131I. Relapsing SAA in 1 patient with MS was treated with antithymocyte globulin (ATG) which induced acute exacerbation of MS. Despite the low total dose of ATG (31.5 mg/kg), complete remission of SAA was obtained. Two other patients developed thyroid disorders, 42 and 106 months after successful immunosuppression with ATG/high-dose methylprednisolone. IHT and subacute thyroiditis were successfully treated with 131I or prednisolone, respectively, without recurrence of SAA in both cases. These are the first documented cases of SAA evolving in the course of MS while the coincidence with IHT was already described. Since enhanced expression of interferon-gamma plays a crucial role in SAA as well as in MS and in IHT, similar pathogenetic principles may apply for these seemingly unrelated disorders.