Leukopenia and remission during azathioprine treatment

Sirs, We thought that Rizzello et al.'s review in Alimentary Pharmacology & Therapeutics,1 on the management of refractory Crohn's disease, had very many important points in this area. They stated that the major problem concerning the use of azathioprine is mostly due to the risk of myelosupression. However, we would also want our colleagues to pay attention to the possible relationship between leukopenia and the maintenance of remission in inflammatory bowel diseases. It is debatable whether neutropenia has a favourable effect on the results of azathioprine therapy.2–6 In this regard, we report an investigation to clarify whether leukopenia during azathioprine therapy reduced relapse rates in inflammatory bowel disease patients. This was a retrospective study based on a total of 31 patients who had been stable on azathioprine therapy for a minimum of 6 months. Three of 31 patients had ulcerative colitis and 28 had Crohn's disease. The data were obtained from patient files followed in the gastroenterology clinics of the Turkiye Yuksek Ihtisas Hospital. The duration of follow-up was 1 year. The lowest leukocyte count during treatment was recorded as ‘leukopenic’ (leukocyte count < 4.3 × 109, n = 10) or ‘nonleukopenic’ (n = 21). Relapse rates after 1 year were compared between leukopenic and nonleukopenic groups via χ2 test (Fisher's exact test). After 1 year, we found that five patients (50%) had relapsed and five patients (50%) maintained their remission in leukopenic group of 10 patients. In the nonleukopenic group, three of 21 patients (14%) relapsed, but 18 patients (86%) maintained remission. There was no statistically significant difference between the leukopenic group and the nonleukopenic group regarding maintenance of remission (P = 0.074). We found that leukopenia on azathioprine therapy does not reduce the relapse rate of inflammatory bowel disease.