NELFCD and Arthritis: Joint fluid and synovial tissue from antibiotic-refractory Lyme arthritis patients contain higher levels of IL-6 and IL-1β, as well as Th1 cytokines and chemokines, compared with patients whose arthritis is resolved after antibiotic treatment, and IL-1β remains elevated in these treatment-refractory patients long after antibiotic therapy [96], [97].