IL-18 and related function proteins associated with tuberculosis severity and screening for active TB among patients with non-mycobacterial community-acquired pneumonia (CAP).

BACKGROUND

Differentiation of active pulmonary tuberculosis (TB) from non-mycobacterial community-acquired pneumonia (CAP) still remains a diagnostic challenge.

OBJECTIVE

The study aimed to quantify the IL-18, IFN-γ, IL-18BP, IL-37, and IP-10 levels in serum and () antigens-stimulated blood cultures from TB or CAP patients and explore if the proteins can be a useful basis for discriminating these diseases.

METHODS

In total, 124 Polish adults, including mild/moderate (M/MTB) or advanced (ATB) TB patients, and CAP patients, were enrolled in the study. The concentrations of IL-18, IL-18BP, IFN-γ, IL-37, and IP-10 in sera and -stimulated cultures were measured by ELISA.

RESULTS

The most specific and sensitive serum proteins discriminating TB from CAP were IP-10 and IL-18BP; however, IP-10 had the highest AUC in the ROC curve for the diagnosis. Serum IP-10 and IL-18BP levels increased significantly in M/MTB or ATB groups. The IL-18BP elevation in ATB group was accompanied by an increase in IL-18. No single protein measured in -stimulated cultures differed TB from CAP patients.

CONCLUSIONS

The combined analysis of serum IL-18BP and IP-10 might be considered as an auxiliary tool in the differentiation of TB from CAP.