Long term effect of IFN treatment in paediatric patients with chronic ITP has not yet been established. We treated nine patients with chronic form of disease aged 17-184 monts (median 90 months), M/F 5/4. Conventional therapy with corticosteroids and HDIVIG failed. None of the patients underwent splenectomy. All patients received 12 doses of alfa 2b IFN 3 MU/mq three times weekly, in seven patients we used repeated courses of IFN therapy.

Results: After the first course of therapy no patient achieved complete remission. Transient normalization of thrombocytes was revealed in five patients. In two patient we observed slight transient increase of platelets up to 50x 109/1, two patients did not respond. One patient is in complete remission after following HD IVIG treatment. Having repeated 12 doses we achieved complete remission in one and a partial remission in other two patients, in which it was possible to stop the treatment with corticosteroids. In the last three patients we observed only temporary slight increase of thrombocytes after repeated treatment. These patients required further treatment.

Increase of the level of platelets in good responders was different in our children that it was previously reported in adults: maximum response was observed much earlier: on therapy days 8-15 in all five good responders.

Patients, who previously showed transient positive response to therapy with HDIVIG, showed also good response to IFN alpha therapy. Children with no response to HDIVIG, did not respond to IFN alpha either.

Side effects were minimal, we observed 2x flu-like syndrom at the beginning of the therapy, in one child temporary slight neutropenia (ANC above 1000x106/1), in another one temporary defluvium capitis. Investigation of autoimmunity markers showed transient positivity of anti Ro antibody in one child after the first course of therapy.

From the economic point of view, treatment with one course of Interferon alfa was approximately 4x cheaper than treatment with one dose of HDIVIG (2 g/kg).

Conclusions: Our results are quite encouraging, but we put emphasis on the necessity of further studies in order to evaluate effects and risks of interferon treatment, especially possible induction of another autoimmune disease. According to the results we have reached, Interferon alfa might be applied for the treatment of chronic ITP in children.