Innate immune responses in Lyme borreliosis: enhanced tumour necrosis factor‐α and interleukin‐12 in asymptomatic individuals in response to live spirochetes

Summary Innate immunity is important for early defence against borrelia spirochetes and should play a role in the clinical outcome of the infection. In order to study early cytokine responses, in vitro differentiated dendritic cells (DCs) and whole blood cells from 21 patients with different clinical outcomes of Lyme neuroborreliosis were stimulated with live borrelia spirochetes. The borrelia‐induced secretion of interleukin (IL)‐4, IL‐10, IL‐12p70, interferon (IFN)‐γ and tumour necrosis factor (TNF)‐α in DCs and IL‐1β, IL‐6, IL‐8, IL‐10, IL‐12p70, TNF‐α, regulated upon activation normal T cell expressed and secreted (RANTES), monocyte chemoattractant protein (MCP)‐1, macrophage inflammatory protein (MIP)‐1α, MIP‐1β and eotaxin in whole blood cells was measured by enzyme‐linked immunospot (ELISPOT) and multiplex arrays, respectively. We found increased numbers of TNF‐α‐secreting DCs (P = 0·018) in asymptomatic seropositive individuals compared to patients with subacute neuroborreliosis and seronegative controls. Asymptomatic individuals were also found to have elevated levels of IL‐12p70 (P = 0·031) in whole blood cell supernatants compared to seronegative controls. These results are in line with previous experiments using cells of the adaptive immune response, indicating that strong T helper type 1 (Th1) proinflammatory responses might be associated with a successful resolution of Lyme disease.