Human chorionic gonadotropin treatment of anti-Hu-associated paraneoplastic neurological syndromes

Objective Paraneoplastic neurological syndromes associated with anti-Hu antibodies (Hu-PNS) are mediated by a T-cell immune response that is directed against the Hu antigens. In pregnancy, many Th1-mediated autoimmune diseases such as rheumatoid arthritis and multiple sclerosis regress. We hypothesised that this decreased disease activity during pregnancy may be related to high human chorionic gonadotropin (hCG) levels. Methods 15 Hu-PNS patients were treated in a prospective, uncontrolled and unblinded trial with 10 000 IU daily of hCG administered by intramuscular injection during 12 weeks. Primary outcome measures were functional improvement defined as a decrease of one or more points on the modified Rankin Scale (mRS) or stabilisation in patients with mRS score <= 3 and improvement of neurological impairment assessed with the Edinburgh Functional Impairment Tests (EFIT). Secondary end points included the change in activities of daily living as evaluated using the Barthel Index. Results Seven of 15 patients (47%) improved on the mRS or stabilised at mRS score <= 3. Four patients (27%) showed significant improvement of neurological impairment as indicated by an overall Edinburgh Functional Impairment Tests score of >= 1 point. Five patients improved on the Barthel Index (33%). Conclusion Comparison with previous studies suggests that hCG may have immunomodulatory activity and may modify the course of Hu-PNS, although well-established confounding factors may have contributed in this uncontrolled trial.