For the non-PJI group, the median (IQR) values of serum CRP (mg/L), synovial CRP (mg/L), serum IL-6 (pg/mL) and synovial IL-6 (pg/mL) were 2.13 (1.00–7.20), 0.67 (0.19–3.72), 4.99 (3.26–7.33) and 1168.97 (303.09–2353.38), respectively. This evidence concerns the gene IL6 and juvenile polyposis syndrome.