Alemtuzumab-induced thyroid eye disease successfully treated with a single low-dose of rituximab.

BACKGROUND Secondary thyroid autoimmunity, especially Graves' disease (GD), frequently develops in patients with multiple sclerosis (MS) following alemtuzumab treatment (ALTZ; anti-CD52). Thyroid Eye Disease (TED) can also develop, and rituximab (RTX; anti-CD20) is a suitable treatment. METHODS Immunophenotyping of blood and thyroid-derived lymphocytes in a patient treated with both ALTZ and RTX. RESULTS A 37-year-old woman with MS developed steroid-resistant active moderate-to-severe TED three years after ALTZ, that successfully responded to a single 500 mg dose of i.v. RTX. Before RTX peripheral B-cells were low, and were totally depleted immediately after therapy. Follow-up analysis four years post-ALTZ and one year post-RTX, showed persistent depletion of B cells, and relative reduction of T regulatory cells in both peripheral blood and thyroid tissue obtained at thyroidectomy. CONCLUSIONS RTX therapy successfully inactivated TED in a patient with low B-cell count derived from previous ALTZ treatment. B-cell depletion in both thyroid and peripheral blood was still present one year after RTX, as a likely cumulative effect of both treatments.