Conclusions: At the beginning of obesity development (children), possibly compensatory reactions prevail, reflected here by an increase in the expression of leukocyte MMPs inhibitor TIMP-1, decrease in the level of leukocyte MMP-2 and plasma MMP-2, MMP2/TIMP-2 ratio, low plasma TNF-alpha and negative correlations between the expression of TIMP-2 and liver (AST, ALT) or fat (TTG) inflammatory markers. Here, MMP2 is linked to obesity due to melanocortin 4 receptor deficiency.