Effective Treatment with Tocilizumab in a Rheumatoid Arthritis Patient Complicated with Human T-cell Leukemia Virus Type 1-associated Myelopathy.

A 61-year-old woman with human T-cell leukemia virus type 1 (HTLV-1)-associated myelopathy (HAM)/tropical spastic paraparesis (TSP) and interstitial pneumonia (IP) was admitted to our hospital. She complained of sicca symptoms, polyarthralgia, and swollen joints. She was diagnosed with rheumatoid arthritis (RA) and Sjögren's syndrome. Methotrexate and anti-tumor necrosis factor therapy were not utilized because of the inclusion of severe respiratory disorders among the complications and the neurological symptoms of HAM/TSP. Tocilizumab monotherapy improved the RA disease activity without exacerbating HAM/TSP. The present case suggests that tocilizumab might be a suitable treatment option in patients with RA and HAM/TSP.