Regulatory T cells in paraneoplastic neurological syndromes

Abstract Focusing on CD4 + CD25 + regulatory T lymphocytes (T reg ), we studied the gene expression of T reg functional molecules in peripheral blood lymphocytes of patients with paraneoplastic neurological syndrome (PNS), including Lambert–Eaton myasthenic syndrome (LEMS) with small cell lung carcinoma (SCLC) and anti-Hu- or anti-Yo-antibody-positive PNS. T reg -rich subsets were sorted from the patients' peripheral blood mononuclear cells, and the mRNA expression levels of their functional genes were measured. The expression levels of FOXP3, TGF-β and CTLA4 mRNA in T reg -rich subsets of PNS patients were down-regulated compared with that of SCLC patients without PNS. These results suggest that T reg dysfunction plays a role in PNS development.