Low-dose cyclosporine A in a patient with X-linked immune dysregulation, polyendocrinopathy and enteropathy

Successful treatment with oral low-dose cyclosporine A given as a single daily dose is reported in a Japanese patient with immune dysregulation, polyendocrinopathy, enteropathy, X-linked syndrome. Immune dysregulation, polyendocrinopathy and enteropathy is a rare and potentially fatal X-linked disease (IPEX, OMIM 304790). It is characterised by multiple autoimmune disorders in infancy, that warrants long-term aggressive immunosuppressive therapy [2, 3,6]; however, prolonged use of immunosuppressants may lead to direct toxicity [3]. We previously reported a Japanese infant with IPEX who presented with a novel mutation of the FOXP3gene [5]. The patient was successfully treated by early initiation of oral low-dose cyclosporine A (CsA) given as a single daily dose combined with low-dose prednisolone; for over 3 years he remained free of the both IPEX signs and therapyrelated toxicity. The patient reported here presented with severe secretory diarrhoea at the age of 2 months, and was diagnosed as having IPEX, based on the duodenal biopsy findings (total villous atrophy with crypt hyperplasia), presence of circulating anti-enterocyte antibody (by the immunohistochemical method using the patient’s serum and normal human ileal tissue: when the patient’s serum or control sera were applied to normal mucosa, only the patient’s serum stained the brush border of ileum epithelial cells) and results of sequence analysis of the FOXP3gene: a novel mutation of T1117G substitution in exon 10 [5]. Complete remission was achieved within a short time following prompt initiation of low-dose CsA (2 mg/kg, single daily dose, initially administered intravenously and later switched to oral administration of Neoral before breakfast), combined with prednisolone (0.5 mg/kg, daily). The peak blood levels of oral CsA (1 h post dosing) were maintained at around 700–800 ng/ml, while the trough blood levels of the drug were less than 25 ng/ml. No extra-intestinal signs were encountered, such as type 1 diabetes mellitus, pancreatitis, thyroiditis, haemolytic anaemia, glomerulonephritis or atopic dermatitis. The patient remained reasonably healthy thereafter and developed well under treatment with low-dose oral CsA given as a single daily dose and prophylactic intravenous gamma-globulin administration (200 mg/kg, administered monthly). The prednisolone dose could eventually be tapered to 0.25 mg/kg, daily.