Bone metabolism during interferon-alpha treatment of essential thrombocythemia.

In-vitro studies have demonstrated that interferon (IFN) has an inhibitory effect on bone formation. Changes in bone metabolism were investigated in 19 patients treated for essential thrombocythemia with IFN-alpha. Serum biochemical parameters of bone remodeling [total alkaline phosphatase, osteocalcin, type-I procollagen carboxy-terminal propeptide (PICP), cross-linked telopeptide type-I collagen (ICTP)] and mineral metabolism (total calcium, inorganic phosphate, parathyroid hormone, 25-hydroxyvitamin D) were measured before and after long-term IFN-alpha treatment. The effects of the cumulative IFN-alpha dose and duration of therapy on biochemical markers of bone metabolism were analyzed. No uniform trend or pattern was observed in the measured biochemical parameters except for ICTP, which decreased after treatment. Correlations indicated modulation of bone metabolism, i.e. remodeling with suppression of resorption, as a consequence of therapy with IFN-alpha.