1. ¹Department of Haematology and Oncology, Medizinische Hochschule, Hannover, Germany
2. ²Department of Haematology and Oncology, Heinrich-Heine-Universität, Düsseldorf, Germany
3. ³Department of Haematology and Oncology, Friedrich-Schiller-Universität, Jena, Germany
4. ⁴Department of Haematology and Oncology, Deutsche Klinik für Diagnostik, Wiesbaden, Germany
5. ⁵Department of Haematology and Oncology, St Georgs-Hospital, Hamburg, Germany
6. ⁶Department of Haematology and Oncology, JW Goethe-Universität, Frankfurt, Germany
7. ⁷Department of Haematology and Oncology, Freie Universität, Berlin, Germany
8. ⁸Department of Haematology and Oncology, Universität Essen, Germany
9. ⁹Department of Haematology and Oncology, Klinikum Südstadt, Rostock, Germany
10. ¹⁰Department of Haematology and Oncology, St Marien-Hospital, Hagen, Germany
11. ¹¹Department of Pathology, Medizinische Hochschule, Hannover, Germany
12. ¹²Department of Haematology and Oncology, Universität Ulm, Germany
13. ¹³Department of Haematology and Oncology, St Johannes-Hospital, Duisburg, Germany

Correspondence: A Ganser, Abteilung Hämatologie, Hämostaseologie und Onkologie, Medizinische Hochschule Hannover, Carl-Neuberg-Strae 1, Hannover D-30625, Germany. Fax: +49 511 532 8041; E-mail: ganser.arnold@mh-hannover.de

Received 11 July 2003; Accepted 29 October 2003; Published online 8 January 2004.

Abstract

Immunosuppression has recently been proposed for low-risk myelodysplastic syndromes (MDS) to reverse bone marrow failure by inhibiting intramedullary secretion of proapoptotic cytokines. We treated 35 MDS patients (24 refractory anaemia (RA), 10 RA with excess blasts and one chronic myelomonocytic leukaemia) with either horse antithymocyte globulin 15 mg/kg/day or rabbit antithymocyte globulin 3.75 mg/kg/day, each for 5 days. Median age was 63 years (range: 41–75). After 1 to 34+ months of follow-up (mean: 15+), four patients experienced complete haematological responses (CR), six good responses (GR) and two minor responses. All CRs and GRs occurred in patients with RA, in whom both horse and rabbit ATG yielded five responses out of 12 (42%). Time to response varied between 1 and 10 (mean: 3) months. The median duration of response was 9+ (1–17+) months; five patients are in continuing response. In all, 23 patients suffered side effects >°II WHO (the degree of toxicity encountered according to the internationally accepted WHO toxicity grading); one patient died 2 weeks after rabbit ATG from rhinocerebral mucormycosis. Parameters that correlated with response were duration of disease and RA subgroup. In our experience, immune-modulating therapy with either horse or rabbit ATG is feasible in patients with RA and short duration of disease.