Regulatory T cells in paraneoplastic neurological syndromes

Focusing on CD4+CD25+ regulatory T lymphocytes (Treg), we studied the gene expression of Treg 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. Treg-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 Treg-rich subsets of PNS patients were down-regulated compared with that of SCLC patients without PNS. These results suggest that Treg dysfunction plays a role in PNS development.