Serum levels of TNF-α, IL-1β, COMP, and CTX-II in patients with Kashin-Beck disease in Sichuan, China

The aim of the study was to detect differences in serum levels of interleukin-1β (IL-1β), tumor necrosis factor-α (TNF-α), cartilage oligomeric matrix protein (COMP), type II collagen (CTX-II) between patients with Kashin-Beck disease (KBD) or osteoarthritis (OA) and to assess the correlation between these differences with the clinical grade of KBD. A total of one hundred fifty adult serum samples were collected; these samples belonged to the KBD group (n = 64), the OA group in KBD-prevalent areas (n = 47) and a healthy control group in non-KBD area (n = 39). Serum levels of TNF-α, IL-1β, COMP, and CTX–II were determined by a sandwich enzyme-linked immunosorbent assay, and the results were compared among the 3 groups (KBD/OA/normal) and between the different grades of KBD as well. The serum levels of IL-1β, TNF-α, COMP, and CTX-II were significantly higher in the KBD and OA group than the healthy adult group (P < 0.001), and TNF-α and IL-1β levels in the KBD group were similar to the OA group (for TNF-α, 14.38 ± 7.42 pg/ml vs. 12.61 ± 4.00 pg/ml, respectively, [P = 0.29]; for IL-1β, 141.53 ± 71.35 pg/ml vs. 135.61 ± 68.60 pg/ml, respectively, [P = 0.63]). However, the COMP level was significantly lower and the CTX-II level was higher in the KBD group than in the OA group (for COMP, 7.03 ± 3.11 ng/ml vs. 9.20 ± 3.51 ng/ml, respectively, [P = 0.003]; for CTX-II, 2.23 ± 0.79 ng/ml vs. 1.80 ± 0.87 ng/ml, respectively, [P = 0.026]). Moreover, no significant correlations were found between clinical grade and serum levels of TNF-α, IL-1β, COMP, and CTX-II for the 3 grades of KBD patients (P = 0.645, 0.481, 0.832, and 0.270, respectively). This study showed that serum levels of COMP in KBD patients decreased and CTX-II levels increased compared with the levels in OA patients, but TNF-α and IL-1β levels in KBD and OA group were similar. In addition, increased serum levels of TNF-α, IL-1β, COMP, and CTX-II were not associated with the KBD grade.