TLR1 and Lyme disease: Furthermore, the presence of genetic variants of TLR1 gene leads to impaired cytokine responses upon challenge of PBMCs with Borrelia. On the one hand, since initiation of host defense responses against Borrelia is dependent on multiple pattern recognition receptors, more research is needed to elucidate the precise role of TLR1/2 in the pathogenesis of Lyme disease.