The circulating immune complexes as a biomarker of the endogenous intoxication in pulmonary tuberculosis

The aim of the study was to establish the concentration of the circulating immune complexes (CICs) with high (CIC 2,5%), medium (CIC 4,2%) and low (CIC 8.0%) molecular weights in patients with pulmonary tuberculosis (TB) as biomarkers of the endogenous intoxication and the degree of severity. We investigated 56 patients diagnosed with pulmonary TB and 36 healthy persons (control group). The patients were assigned to 2 groups: the study group 1 (I SG) included 29 patients in which the test established the drug susceptible TB and in the study group 2 (II SG) that included 27 patients with multidrug-resistant TB (MDR-TB). The inclusion criteria were: primary detected pulmonary TB, age older than 18 years, confirmed drug susceptibility (I SG) and confirmed MDR-TB (II SG). The exclusion criteria were: anti-TB treatment in anamnesis, extrapulmonary TB, age below 18 years, HIV infection, severe somatic diseases. The method of CIC quantification consisted in placing 50 l serum into 3 tubes followed by adding 100 l borate buffer and solution of 2.5%, 4.2% and 8.0% polyethylene glycol. The tubes were incubated 15 minutes at 25C and the optical density was assessed at the wavelength 340 nm. The results were compared with the general blood count and leucocital intoxication index Kalf-Kalif (LIIKK) as an alternative method to identify endogenous intoxication. As the results of the research we established that the peak level was observed for CICs with high and medium molecular weight, wrereas less pronounced it was for CICs with low molecular weight. The high severity of the endogenous intoxication predominated in the I SG and middle degree in the IISG, without achieving the statistical significance. LIIKK was lower in study groups comparing with the control healthy subjects due to increased count of eosinophils.