IP-10 level decreases during antituberculous treatment
After two months of antituberculous therapy (median 69; IQR:64 -78.5 days from treatment onset) IP-10 and IFN-γ levels in QFT tubes were measured in 25 children with ATB, 29 with LTBI, and 6 TB contacts. We noticed a significant decrease in the IP-10 but not IFN-γ level in the whole group after two months of treatment (p = 0.0013 and p = 0.6, respectively) (Figure 3A and 3C). This decrease resulted from a significant decline in the IP-10 concentration in the ATB group (Figure 3B and 3D). No significant decline in IP-10 level was observed in LTBI group (p = 0.09).
After the initial phase of chemotherapy IP-10 responses still differed significantly between Mtb.- infected and uninfected children (median 1324.4 pg/ml; IQR: 210.9 - 10134.9 pg/ml vs median 111.5 pg/ml; IQR: 0 - 164.6 pg/ml, p = 0.008). IP-10 was significantly higher in children with ATB (median 4139.7 pg/ml; IQR: 1090- 10464.6 pg/ml) than in TB contacts (median 111.5 pg/ml; IQR: 0 - 164.6 pg/ml) (p = 0.0007). However, no significant differences were found between TB contacts and children with LTBI (median 658.2 pg/ml; IQR: 36.8 - 5295.4 pg/ml) (p > 0.05). On follow-up visit we still observed a significant difference in IP-10 level between ATB and LTBI groups (p = 0.015). Of note, no discrepancies in IFN-γ concentrations were found between children with ATB, LTBI, and TB contacts (data not shown).