Introduction: substantial causes of high mortality (30-50%) of people with severe infections treated in intensive care units (icUs) are still inadequately known in terms of mechanisms and insufficient diagnostic tools for immune responses in sepsis. Material and methods: the aim of this study was to establish a practical value of determining the concentration of chosen proteins (by elisa) in peripheral blood as potential in early diagnostics of severe infections, paying special attention to their prognostic values. Results: in 163 patients treated in icUs, changes were assessed in the concentration of chosen proteins relating to the tlr4 receptor signalling pathway, including its effectors of pro-and anti-inflammatory cytokines (il-1ra, tNF-α, stNFr1, il-6, il-10, stlr4, MyD88, tNFaiP3/a20, HsP70, and HMgB1). in the analysis of changes in the process of immune response in severely ill patients with and without infections, a significantly higher concentration of stNFr1 was observed in patients with infections than those who deceased. in the roc curves tests, it was noted that an assessment of the concentration of stNFr1 proteins (aUc = 0.686 and cutoff point = 24.841 pg/ml) was a particularly efficient tool, with prognostic significance in patients with infections. Conclusions: in other patients treated in an icU, the efficiency of determining il-6 (aUc = 0.736) was confirmed and at the same time, the effectiveness of this cytokine in predicting death in cases with infections was excluded. the results of the present study are encouraging, suggesting the benefits of undertaking multi-center clinical trials, which consider monitoring stNFr1 in different groups of patients with infections treated in intensive care units.