Cyclophosphamide in Treating Young Patients With Severe Autoimmune Enteropathy

DISEASE CHARACTERISTICS: Diagnosis of severe autoimmune enteropathy Condition is resistant to conventional therapy Histologic evidence of severe villous atrophy with intense lymphocytic infiltrate of the lamina propria by small intestinal biopsy within the past 3 months Disease failed to respond after ≥ 2 months of corticosteroid therapy at a dose of ≥ 0.5 mg/kg/day or ≥ 40 mg/day for patients > 20 kg AND 1 of the following therapies: Cyclosporine resulting in ≥ 1 whole blood level of > 200 ng/mL Tacrolimus resulting in ≥ 1 whole blood level of 5 ng/mL At least 50% estimated caloric needs provided by parenteral nutrition History of intractable diarrhea, defined as frequent watery stools for > 3 months that does not respond to dietary restriction No celiac disease, defined by a history of positive antiendomysial antibody or tissue transglutaminase antibody No primary immunodeficiency or x-linked autoimmunity-allergy dysregulation PATIENT CHARACTERISTICS: Performance status Lansky 60-100% Life expectancy Not specified Hematopoietic Not specified Hepatic Not specified Renal Not specified Cardiovascular Ejection fraction ≥ 40% OR shortening fraction ≥ 20% Pulmonary FVC or FEV_1 ≥ 50% of predicted (for patients > 8 years of age) No clinically abnormal pulmonary function or abnormal pulse oximetry (for patients ≤ 8 years of age) Other Not pregnant Negative pregnancy test Fertile patients must use effective contraception during and for at least 9 months after completion of study treatment No known chromosomal abnormality PRIOR CONCURRENT THERAPY: Biologic therapy No immunizations for at least 6 months after completion of study treatment Endocrine therapy See Disease Characteristics At least 5 days since prior corticosteroids No concurrent dexamethasone as an anti-emetic Other At least 5 days since other prior immunosuppressive medications (e.g., tacrolimus or cyclosporine)