CST3 and chronic kidney disease: B2 cells were negatively associated with age (r = −0.150, P = 0.003), SCr (r = −0.153, P = 0.003), cystatin C (r = −0.127, P = 0.022), BUN (r = −0.158, P = 0.002), and CKD (r = −0.187, P < 0.001), and were positively correlated with hemoglobin (r = 0.105, P = 0.042), lymphocytes (r = 0.596, P < 0.001), T lymphocytes (r = 0.474, P < 0.001), NK cells (r = 0.200, P < 0.001), and the eGFR (r = 0.142, P = 0.006).