Association between Serum Cys C and PTB Cavitation

Abstract

Background. Cystatin C (Cys C) not only regulates the body’s immune defenses but also contributes to tissue degradation and destruction by causing an imbalance between protease and antiprotease in infectious diseases. Is Cys C involved in pulmonary tuberculosis (PTB) infection and cavitation? We therefore conducted a retrospective study on this question to provide a basis for further studies. Methods. Cavitary PTB patients, noncavitary PTB patients, and healthy controls were recruited in our study. Serum Cys C, CRP, BUN, UA, and CR were measured in all subjects, and the Kruskal-Wallis test was used to compare medians of these clinical parameters in different groups. The Spearman rank correlation test was used to determine correlations between variables. In addition, a multivariate analysis using binary logistic regression was used to identify factors associated with PTB cavitation. Results. In our study, elevated serum Cys C levels were found in cavitary PTB patients compared to healthy controls and noncavitary patients ( $p=0.022$ ). Serum Cys C levels were statistically correlated with serum BUN and CR concentrations ( $r=0.278$ , $p=0.005$ ; $r=0.281$ , $p=0.004$ ) in PTB patients. The binary logistic regression analysis showed that elevated serum Cys C levels were correlated with pulmonary cavitation in PTB patients ( $\text{OR}=1.426$ , 95% CI: 1.071–1.898). Conclusion. Elevated serum levels of Cys C are associated with pulmonary cavitation in PTB patients.