Ineffectiveness of interferon-gamma in the treatment of idiopathic myelofibrosis: a pilot study.

It has been proposed that interferon-gamma (IFN) inhibits collagen synthesis in myeloproliferative disorders through an inhibitory effect on PDGF and TGF-beta. We therefore evaluated the role of IFN-gamma on bone marrow fibrosis in idiopathic myelofibrosis (IMF). After a 3-month observation period, nine patients (five female, four male), median age 64 years (range 43-72 years), received 3 x 3 mU IFN-gamma/week over 6 months and were monitored after withdrawal of IFN-gamma for further 3 months. Three out of nine patients have completed the study according to the protocol. Six patients had to be withdrawn from IFN-gamma due to the following reasons: bacterial infection (three patients), splenic infarction or deterioration of splenomegaly (one patient, each) and refusal to continue IFN-gamma (one patient). Results from seven patients treated for at least 8 weeks were considered measurable. Leukopenia, initially present in one of the evaluated patients, deteriorated during IFN-gamma treatment. This patient died during the observation period shortly after withdrawal of the therapy as a result of septicemia. Transfusion-dependent anemia, initially observed in two of the evaluated patients, deteriorated during the IFN-gamma treatment. Bone marrow fibrosis increased in three patients, whereas it remained unchanged in another and improved in a further patient. Splenomegaly improved in two patients but deteriorated markedly in one. Taking these observations together, four patients had disease progression during IFN-gamma treatment, two had stable disease and one could be qualified as a partial responder. According to these data IFN-gamma cannot be considered as a treatment option for patients with IMF.

Homocysteine levels in polycythaemia vera and essential thrombocythaemia.

Patients with polycythaemia vera (PV) or essential thrombocythaemia (ET) have an increased risk of arterial and venous thromboembolic complications. Since hyperhomocysteinaemia (HHC) is a risk factor for vascular disease, we investigated the frequency of HHC in these disorders and analysed a possible association of elevated plasma homocysteine levels with vascular complications. In the cohort of 134 patients from Vienna (69 female, 65 male, median age 65.5 years, range 21-91 years) with PV (n = 74) or ET (n = 60), plasma homocysteine levels were significantly higher compared to 134 healthy controls. Median homocysteine level was 12.3 micromol/l (range 3.5-48.4 micromol/l) in patients with PV or ET and 8.9 micromol/l (range 4.8-30.5 micromol/l) in normal controls (P < 0. 0001). In addition to the 134 patients from Vienna, 48 patients (28 female, 20 male; median age 66.5 years, range 24-82) from Vicenza with PV (n = 25) or ET (n = 23) were included to evaluate the impact of HHC on the risk of thrombosis. Of 59 patients with HHC (44 from Vienna and 15 from Vicenza) 18 (31%) had a history of arterial and 10 (17%) of venous thrombosis. Of 123 patients with normal homocysteine levels, 30 (24%) had arterial and 16 (13%) had venous thromboses. The difference between the two groups was statistically not significant. Even though mild to moderate HHC occurred in a larger number of patients with PV or ET and thrombosis, it can presently not be regarded as an additional risk factor for thrombosis.