UNLABELLED: Several prospective randomized studies have shown that the treatment of chronic myeloid leukemia with interferon alfa (IFN alpha) prolongs the survival by comparison with conventional chemotherapy. However, long-term treatment with Interferon alfa (IFN alpha) can produce or exacerbate immune-mediated complications (IMC). The purpose of this study was to analyze the experience with IMC in patients with chronic myelogenous leukemia (CML) undergoing IFN alpha treatment.

PATIENTS AND METHODS: The occurrence of IMC was evaluated in 76 patients (47 male; 29 female) with Philadelphia chromosome (Ph)-positive CML. The median of age was 45 years and the duration of disease was 3.9 years. Diagnostic criteria of IMC were performed in patients with sign and symptoms suggestive of particular disorders.

RESULTS: Well-documented and clinically evident complications developed in 7 patients after a median of 19 months (range 1-84) of IFN alpha treatment. These included 9.2% patients with Ph-positive CML treated with IFN alpha-containing regimens. Hypothyroidism (H) occurred in 1 patient (1.3%), immune-mediated hemolysis (HEM) in 2 patients (2.6%) and connective tissue disorders (CTD) in 4 patients (5.3%) [2-SLE, 1-Raynad's syndrome and 1-mixed connective tissue syndrome (MCTS)]. IFN alpha was discontinued in 3 patients and the dose was reduced in 2 patients. Five of 7 patients (75%) with immune-mediated complications had some degree of cytogenetic response at the time of the event. The association with female sex was strong and significant (86% vs 33.6%, x2; 48; p = 0.02).

CONCLUSION: The frequency of IMC of clinical relevance with interferon alfa therapy in CML increased (long-term therapy). The patients treated with interferon alfa should be monitored for sign and symptoms of autoimmunity.