Mitsuru Saito

Case: This report describes a 25-year-old female professional triathlete with right external iliac artery endofibrosis (EIAE) that was definitively diagnosed on contrast-enhanced magnetic resonance images obtained immediately after treadmill running. The EIAE was treated by percutaneous transluminal angioplasty. By 8 weeks after surgery, she had no symptoms of claudication or pain in the right thigh after a 1-hour running session. There has been no recurrence in 1 year postoperatively. Conclusion: EIAE is a rare condition and difficult to diagnose in a timely manner because symptoms and radiographic imaging features appear only during intense exercise. Our patient was successfully treated with percutaneous transluminal angioplasty.

Invariant natural killer T (iNKT) cells are innate-like T lymphocytes that express an invariant T cell receptor α chain and contribute to bridging innate and acquired immunity with rapid production of large amounts of cytokines after stimulation. Among effecter subsets of iNKT cells, follicular helper NKT (NKT FH ) cells are specialized to help B cells. However, the mechanisms of NKT FH cell differentiation remain to be elucidated. In this report, we studied the mechanism of NKT FH cell differentiation induced by pneumococcal surface protein A and α-galactosylceramide (P/A) vaccination. We found that Gr-1 + cells helped iNKT cell proliferation and NKT FH cell differentiation in the spleen by producing interleukin-27 (IL-27) in the early phase after vaccination. The neutralization of IL-27 impaired NKT FH cell differentiation, which resulted in compromised antibody production and diminished protection against Streptococcus pneumoniae infection by the P/A vaccine. Our data indicated that Gr-1 + cell–derived IL-27 stimulated mitochondrial metabolism, meeting the energic demand required for iNKT cells to differentiate into NKT FH cells. Interestingly, Gr-1 + cell–derived IL-27 was induced by iNKT cells via interferon-γ production. Collectively, our findings suggest that optimizing the metabolism of iNKT cells was essential for acquiring specific effector functions, and they provide beneficial knowledge on iNKT cell–mediated vaccination-mediated therapeutic strategies.