Cytokines and the pathogenesis of neuroborreliosis: Borrelia burgdorferi induces glioma cells to secrete interleukin-6.

Lyme disease is a multisystemic disease caused by a tickborne spirochete, Borrelia burgdorferi. Neuroborreliosis is characterized by intrathecal production of antibodies specific for the spirochete. This suggests that spirochetal infection of the central nervous system produces conditions that support the maturation of B lymphocytes to immunoglobulin-secreting cells. Interleukin 6 (IL-6) stimulates B cell differentiation into antibody-secreting cells. The present study was undertaken to determine whether B. burgdorferi can stimulate cells of central nervous system origin to secrete IL-6. C6 rat glioma cells cultured with spirochetes induced secretion of IL-6 activity. Peak stimulation was achieved at 24 h with 25 spirochetes per glioma cell. Glioma cells were also stimulated to produce IL-6 by interleukin 1 and tumor necrosis factor. That very few spirochetes are found in Lyme disease patients suggests that biologic amplification factors derived from the organism or the host, or both, are responsible for the pathogenesis of this disease. IL-6 can now be added to the growing list of such factors.