Beneficial effect of pentoxifylline on thyroid associated ophthalmopathy (TAO)*: a pilot study

We have previously found that pentoxifylline (Ptx) inhibited cytokine induced HLA-DR expression and glycosaminoglycan (GAG) synthesis by retroorbital fibroblasts. We have now tested the clinical efficacy of Ptx in treating TAO. Ten patients with moderately severe ophthalmopathy were selected for study. All patients were euthyroid before and during the 12 weeks of the Ptx therapy. Serum GAG, TNF-alpha, anti-TSH-receptor, anti-eye muscle, anti-thyroglobulin and anti-thyroid peroxidase antibodies were determined sequentially. At the end of 12 weeks eight of the ten patients showed improvement in soft tissue but not in proptosis or extraocular muscle involvement. At baseline the levels of GAG (5.2+/-0.92 mg/dl v.s. 0.7+/-0.14 mg/dl, p<0.001) and TNF-alpha (33.6+/-6.6 pg/ml v.s. 5.4+/-1.3 pg/ml, p<0.001) were increased in patients compared to controls. They gradually decreased in the eight patients who responded to Ptx: after 4, 8 and 12 weeks of therapy serum GAG was 3.4+/-0.42 mg/dl, 2.5+/-0.77 mg/dl (p<0.01) and 1.1+/-0.2 mg/dl (p<0.001), respectively and serum TNF-alpha was 20.9+/-4.8 pg/ml, 14.9+/-2.2 pg/ml (p<0.05) and 9.7+/-1.8 pg/ml (p<0.01), respectively. Serum GAG and TNF alpha did not fall in the two patients who did not respond. The titre of anti-eye muscle antibodies but not anti-thyroid antibodies were lower at 12 weeks. Ptx has a beneficial effect on inflammatory symptoms of TAO and associated laboratory parameters in the majority of patients.