Preddie DC et al. (2006) Mycophenolate mofetil for the treatment of interstitial nephritis. Clin J Am Soc Nephrol 1: 718–722

Acute interstitial nephritis (AIN) is often caused by an allergic reaction to a medication; it can also be associated with autoimmune conditions and with various infections. Most causes of AIN seem to respond to immunosuppressants such as corticosteroids, but some patients are resistant to or intolerant of corticosteroid therapy. Preddie et al. have investigated whether the immunosuppressant mycophenolate mofetil (MMF) could be useful in such patients.

The study included eight patients with biopsy-proven AIN who had received ≥6 months of corticosteroid treatment but had suffered relapses, intolerance or resistance to corticosteroid therapy. Patients received twice-daily MMF doses ranging from 500 mg to 1,000 mg.

After a mean of 28 months of follow-up (range 14–40 months, with a mean of 24 months of MMF treatment), mean serum creatinine level decreased from 2.3 mg/dl to 1.6 mg/dl (203 μmol/l to 141 μmol/l). Six of eight patients showed improvement in renal function—defined as a decrease in serum creatinine level of ≥0.3 mg/dl (26.5 μmol/l)—following MMF treatment. Serum creatinine levels remained stable in the other two patients. At their final follow-up visit, all patients had discontinued corticosteroids, and five patients had discontinued MMF therapy. One patient had a myocardial infarction during MMF therapy and died of cardiac disease, but this was thought to be unrelated to MMF. No serious adverse effects of MMF were reported.

Although further studies are needed, MMF appears to be a useful alternative treatment for patients with steroid-resistant or steroid-intolerant AIN, and might be a good first-line option in patients with conditions such as obesity or diabetes, for whom steroid treatment is undesirable.