To the Editor:
The CD28-CD80/CD86 costimulatory pathway is essential in enhancing and optimizing T cell activation and cytokine production in rheumatoid arthritis (RA). Cytotoxic T lymphocyte-associated antigen 4 (CTLA4) is a homolog of CD28. It can competitively bind to CD80/CD86 and downregulate naive and memory T cell proliferation, cytokine production, and humoral immune response. Its human soluble fusion protein, CTLA4-Ig, was approved for the treatment of active RA by the US Food and Drug Administration in 20051. Several animal studies suggest benefits of CTLA4-Ig in other immunologic diseases such as asthma. However, we describe here 2 cases of RA complicated with relapse of asthma while undergoing CTLA4-Ig therapy.
A 53-year-old Chinese woman had a 9-year history of refractory RA, and was treated with methotrexate (MTX) 7.5 mg per week and prednisone 3 mg daily. She had started CTLA4-Ig 10 mg/kg in combination with stable dosages of MTX and prednisone on August 20, 2009, because of her high RA activity. Four days later, …
Address correspondence to Dr. J. Bao; E-mail: baojun{at}smmu.edu.cn