Oligoclonal T cell repertoire in cerebrospinal fluid of patients with inflammatory diseases of the nervous system

OBJECTIVE—To evaluate the T cell receptor β chain variable region (TCRBV) gene usage ex vivo in CSF cells and peripheral blood mononuclear cells (PBMCs) collected from patients with autoimmune and inflammatory diseases of the nervous system. METHODS—A novel sensitive seminestedpolymerase chain reaction coupled with heteroduplex analysis was developed. RESULTS—Under these experimental conditions, the minimal number of cells required for the analysis of the whole T cell repertoire was established at 2.5×104—sufficient to evaluate most of the samples collected during diagnostic lumbar punctures. In the 21 patients examined, restrictions in TCRBV gene family usage were not seen. However, using heteroduplex analysis, oligoclonal T cell expansions were found in the CSF of 13 patients and monoclonal expansions in five patients. The T cell abnormalities found did not correlate with intrathecal IgG production or with any clinical variable considered. CONCLUSION—T cell clonal expansions, useful for further characterisation of pathogenetic T cells, can be found during the course of nervous system inflammations, but this abnormality is probably not disease specific.