Association between Serum Cys C and PTB Cavitation.

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 (OR = 1.426, 95% CI: 1.071-1.898).

Conclusion: Elevated serum levels of Cys C are associated with pulmonary cavitation in PTB patients.