TLR2 expression on select lymphocyte subsets as a new marker in glomerulonephritis

Toll-like receptor (TLR) signaling may be involved in autoimmune kidney disorders and has been implicated in proliferative and non-proliferative glomerulonephritis (PGN and NPGN). In this study, we investigated the expression of TLR2 on T and B lymphocytes in relation to selected clinical parameters in patients with PGN and NPGN. We collected peripheral blood from the ulnar vein of patients with PGN (n = 15) or NPGN (n = 22) and healthy volunteers (n = 20). The percentage of peripheral blood mononuclear cells expressing TLR2 was determined with flow cytometry. TLR2 expression on T and B lymphocytes was increased in PGN patients compared with NPGN patients and controls (p ≤ 0.001). In patients with PGN, TLR2 expression correlated negatively with the serum concentrations of IgG and albumin and positively with urine protein excretion. Receiver operating characteristic (ROC) analysis indicated that TLR2 expression is a highly specific marker to distinguish PGN patients from NPGN patients and controls, especially on CD4+ T lymphocytes. Its use as a non-invasive marker of disease should be further investigated.