Antiphospholipid syndrome associated with immunotherapy for patients with melanoma

Immunotherapy for patients with cancer is associated with severe side effects, including the possible induction of autoantibodies. The latter was proven for antithyroid microsomal and antithyroglobulin antibodies.

This study was designed to evaluate antiphospholipid antibodies (APA) in 30 patients receiving three different forms of immunotherapy for disseminated melanoma using interleukin-2 (IL-2), alpha-interferon (alpha-interferon) or the combination of both.

APA were detected in none of 18 patients treated with IL-2 alone, 2 of 4 (50%) treated with alpha-interferon alone, and 3 of 8 (37.5%) treated with the combination of both. In the last group, increased concentrations of APA were observed, while the patients were still receiving alpha-interferon alone. APA levels were not detected in any of 10 patients with melanoma who were not treated with alpha-interferon or IL-2. In patients with increased APA, five of five (100%) had a prolongation of the partial thromboplastin time and 4 or five (80%) had deep venous thrombosis, which in one patient was followed by pulmonary embolism.

The high incidence of therapy-induced elevated APA concentrations suggests that these should be carefully monitored in all patients receiving immunotherapy with alpha-interferon.