Objective: To explore the expression of T cell immunoglobulin and mucin domain protein 3 (Tim-3) on CD56(+) NK cells in peripheral blood and its correlation with liver fibrosis indicators in patients with advanced schistosomiasis.
Methods: Tim-3 expression on CD6(+) NK cells from 28 patients with advanced schistosomiasis and 30 healthy controls was determined by flow cytometry. The serum levels of IFN-y and IL-4 were detected by enzyme-linked immunosorbent assay (ELISA). Fibroscan analyzer was used for liver stiffness measurement (LSM) to determine the extent of liver fibrosis. Four serological indicators of liver fibrosis, collagen type III N-peptide (PIIP N-P), Laminin (LN), collagen IV (CIV) and hyaluronic acid (HA) were measured by the Automated Chemiluminescence Immunoassay Analyzer.
Results: Flow cytometry analysis showed that Tim-3 expression on CD56(+) NK cells in advanced schistosomiasis patients was (62.3±11.4)%, significantly higher than that (52.1±6.5)% (P< 0.01). In patients with advanced schistosomiasis and the healthy controls, the levels of PIIIP N-P were (86.5±29.5) ng/mL and (22.0±7.8) ng/mL, LN (49.3±21.5) ng/mL and (20.4±6.3) ng/mL, CIV (67.5±22.3) ng/mL and (22.0±3.9) ng/mL, HA (645.9±483.1) ng/mL and (54.7±27.7) ng/mL, respectively. There were significant differences in all these indicators between the two groups (P<0.05). The levels of IFN-y were (93.9?20.1) ng/L and (107.7?24.6) ng/L, and those of IL-4 were (46.6±11.8) ng/L and (28.9±8.9) ng/L respectively in patients with advanced schistosomiasis and the healthy controls, both with significant differences (P<0.05). Spearman nonparametric correlation analysis showed that Tim-3 expression on CD56(+) NK cells in patients was positively correlated with the levels of LSM, PIIIP N-P, LN, CIV and IL-4 (r=0.528-0.834, P<0.01), but negatively with serum IFN-y (r=-0.501, P<0.01). No correlation was found with the HA level (r=0.352, P>0.05).
Conclusion: The expression of Tim-3 on peripheral CD56(+) NK cells increases in patients with advanced schistosomiasis compared with the healthy controls, and it positively correlates with the levels of LSM, PIIIP N-P, LN, CIV and IL-4, four indicators of liver fibrosis.