According to the results, the risk alleles for Latvian LB patients are the HLA-DRB1*07, -DRB1*17(03), -DRB1*04 and -DRB1*15(02) alleles, whereas, the development of severe forms of neuroborreliosis is strongly associated with the HLA-DRB1*07 allele. This evidence concerns the gene HLA-DRB1 and Lyme disease.