Proinflammatory cytokine profile in active kidney tuberculosis patients

Mycobacterium tuberculosis is a facultative intracellular pathogen that developes specific T cell response expressed by the production of IL-12, IFN-gamma, and TNF-alpha. The response has been quite well investigated in the experimental models, however, there is little information about certain cytokine levels in patients with extrapulmonary tuberculosis. The shortage of data pertains also to its most common form-kidney tuberculosis, especially when bacilli dissemination into the blood circulation has occurred.

The aim of our study was to examine simultaneously the frequency of Mycobacterium tuberculosis presence in the blood circulation and the serum cytokine concentration during kidney tuberculosis to approach their relationship in the clinical infection process. It is considered that cytokine levels do not correlate with localisation of tuberculosis (pulmonary vs. extrapulmonary), however, there is little information about the cytokine levels in patients with kidney tuberculosis.

30 patients attending the urology clinic with suspicion of kidney tuberculosis were evaluated. Serum concentrations of selected cytokines in patients with urine, urine and blood Mycobacterium tuberculosis presence were quantified by ELISA and compared to PCR negative patient and group of healthy people.

Our study demonstrates the increase of TNF-alpha and IL-12 level in comparison to control group. TNF-alpha concentration was about 2-fold higher in the positive patients than it was in control group; IL-12 concentration was about 4-fold higher and the differences between IL-12 levels were statistically important (p < 0.05). However, no significant differences were found in IFN-gamma level among all groups. Using Spearman correlation rank test, a significant correlation was found between TNF-alpha and IL-12 in the positive patient group. The correlation factor was more significant for the group of patients with Mycobacterium tuberculosis present in blood and urine than it was in urine positive PCR group (r = -0.66 vs. r = -0.51).