Leukocyte and platelet lowering by some interferon types during viral hepatitis treatment

The hematologic toxicity (leukothrombocytopenia) of interferon therapy is well known and frequently observed; it may vary, however, according to the type of interferon administered.

We retrospectively assessed 158 patients with chronic viral hepatitis treated for 6-12 months with alpha (recombinant, lymphoblastoid or leukocyte) or beta interferon to monitor leukothrombocytopenia.

During treatment, a significant decrease in leukocyte and platelet counts was detected in 48% and 43% of patients, respectively. The maximum decrease (31% and 26% of pre-treatment values; p<0.01) occurred after 4.9 and 4.2 months of treatment. No patient showed clinical symptoms of leukopenia or thrombocytopenia. Beta-interferon yielded the smallest decreases in leukocyte and platelet counts (-21% and -16% of pre-treatment values, respectively). Among alpha interferons, the lymphoblastoid (9 MU/week) produced the largest decrease both in leukocyte (38%; p<0.05 vs any other type) and in platelet (32%) number. The same dose of leukocyte interferon had the smallest effect (leukocytes: -27%; platelets: -2%), while recombinant interferon showed intermediate toxicity (-32% and -26% respectively).

From this retrospective study, the hematologic toxicity of alpha and alpha interferons usually emerges as mild. However, leukopenia and thrombocytopenia may be induced more frequently by some of these interferon types.