Poliklinik für Rheumatologie, Universitätsklinikum Schleswig-Holstein, Campus Lübeck and Rheumaklinik Bad Bramstedt, Germany
Correspondence to: P. Aries, Rheumaklinik Bad Bramstedt, Oskar-Alexander Strasse 26, 24576 Bad Bramstedt, Germany. E-mail: aries{at}rheuma-zentrum.de
SIR, in Wegener's granulomatosis (WG) standard therapy with cyclophosphamide (CYC) is limited by treatment-associated short- and long-term morbidity and mortality as well as insufficient response in about 10% of all cases [1]. Several therapeutic regimes have been used for refractory disease with varied results, including monoclonal antibodies to TNF- [2] and different surface markers of T-cells (CD4, CD 52) [3] and B-cells (CD20) [4]. We report two patients with WG responding insufficiently to standard therapy, TNF blockade and rituximab in succession, but treated successfully with intravenous (i.v.) azathioprine (AZA). Both participants who were treated gave their informed consent. They fulfilled the Chapel Hill Consensus Conference definition [5] and the ACR criteria [6] for WG. Diagnosis was based on a typical clinical presentation and biopsy findings, supported by the presence of cANCA/PR3-ANCA. Sufficient activity of thiopurine methyltransferase (TPMT), an inactivating enzyme in the metabolism of AZA, was determined before treatment. AZA (1200 mg in 1000 ml NaCl 0.9% i.v., corresponding to 17 mg/kg body weight) was given over a 24-h period (50 ml/h) once monthly with antiemetic prophylaxis (ondansetron). Additive AZA was given orally (100 mg per day) in weeks 2 and 3 between each pulse, with regular monitoring of the white blood cell count. After completing six pulses, therapy was continued with daily AZA (100150 mg/day) orally.
Patient 1, a 33-yr-old female with WG and predominantly ENT involvement, was started on CYC (1300 mg every 6 weeks i.v.) and prednisolone (PRD). Because of the development of an increasing retro-orbital mass after 9 months of CYC, therapy was intensified by adding infliximab (5 mg/kg body weight every 6 weeks). Continuing and wearing right-sided supraorbital pain with an increasing demand for PRD (60 mg/day) was attributed to massive progress of the retrobulbar granuloma. Thus, CYC and infliximab were stopped after 28 weeks of combined treatment and rituximab (375 mg/m2) was started in combination with MTX (20 mg/week i.v.) instead. In addition to further progress of the retro-orbital mass, a necrotizing and destructive inflammation of the right-sided lower eyelid soon appeared (Fig. 1). The decision was made to change treatment to i.v. azathioprine pulse therapy (1.2 g). After the first two i.v. applications, less pain and better vision were reported by the patient. Strong improvement continued up to the sixth AZA pulse, and regression of endonasal and orbital disease activity and a better motility of the right eye were documented during the next 12 months (Birmingham Vasculitis Activity Score (BVAS) 1:0, BVAS 2:3).
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We report the successful induction of remission by i.v. AZA pulse therapy in two patients with refractory WG during standard treatment. Intravenous AZA was used initially in inflammatory bowel disease as a loading dose to decrease the time to response and was later proved to be safe and of clinical benefit in a pilot study in patients with ulcerative colitis [7, 8]. AZA is a purine analogue and its postulated mechanism of action is apparently at the level of DNA [9]. As demonstrated recently, AZA and its metabolites play a unique role in the control of T-cell apoptosis by the modulation of Rac1 activation upon CD28 costimulation [10]. Binding of AZA metabolites to the small GTP-binding Rac1 leads to decreased activation of Rac1 target genes, such as NF-B and bcl-XL, leading to a mitochondrial pathway of apoptosis.
The authors have declared no conflicts of interest.
References
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