Endocrine Abstracts

Introduction: Alemtuzumab, a humanized monoclonal antibody against CD52, is effective in the treatment of early relapsing-remitting multiple sclerosis (MS). Thyroid side-effects such as Graves’ disease have been already described. We describe one case of unusual subacute thyroiditis after alemtuzumab treatment.

Clinical case: A 38 year-old-female was treated by alemtuzumab for 2 years. She was referred for hyperthyroidism with 10 kg weight loss, diarrhea and palpitations. Clinical examination found cervical pain and fever. Thyroid function tests revealed low TSH at 0.0170 mUI/l (N 0.270–4.20), increased fT4: 71.4 pmol/l (N 12–23) and fT3: 18.2 pmol/l (N: 3.84–7.07). Thiamazol (20 mg bid) and propranolol (20 mg tid) were started with daily neutrophil evaluation. First hypothesis was Graves’ disease, since it is currently described with alemtuzumab. Blood tests revealed increased CRP: 156 mg/l (N<4 mg/l) without increased leukocytes. Ceftriaxone was started in front of a urinary infection suspicion. Finally, bacteriological analyses (blood and urine) were negative and ceftriaxone was discontinued. After 3 days under thiamazol treatment, fT4 increased up to 100 pmol/l and fT3 up to 26.5 pmol/l without clinical improvement. Thyroid ultrasonography showed isolated heterogeneous parenchyma. Technetium scintigraphy showed no uptake; allow us to make the diagnosis of subacute thyroiditis. Finally, anti TSH receptor, thyroglobulin and thyroperoxidase antibodies results came back negative. Thiamazol was resumed, prednisolone (1 mg/kg per day) started. After 1 week, neck pain and fever disappeared and fT3, like CRP, were normalized. After 2 weeks, fT3 and fT4 were in the normal ranges.

Discussion: Although subacute thyroiditis is not known as an auto-immune disease, an increase of its incidence rate is found after alemtuzumab or INF-alpha treatment suggesting an immune participation. Moreover, this rise is not found after alemtuzumab therapy for chronic B cell leukemia (suggesting a specific background in MS patient). We describe here the case of unusual severe subacute thyroiditis after alemtuzumab treatment.