Criteria of the systemic inflammatory response syndrome in patients with community-acquired pneumonia

The absence of a single approach to the determination of severe pneumonia troubles the objective evaluation of the patients' state. It is proposed that the disease's severity reflects the apportionment of patients with pneumonia with systemic inflammatory response syndrome (SIRS). This study was planned to demonstrate how the clinical laboratory criteria of SIRS in pneumonia reflect the systemic inflammatory response of the organism.

We examined 46 patients aged 36–58 years. Twenty-two patients had the middle-severe type (first group) and 24 patients (second group) had the severe type of pneumonia. We determined the cytokine concentrations (IL-6, IL-8, TNF-α) and LPS-binding protein (LPS-SP) in the blood serum using the immunochemo-luminescent method on the immunochemoluminescent analyzer 'IMMULITE One' (USA) 1, 3, 10 and 17 days after the treatment's onset. The C-reactive protein concentration was appreciated by the latex-agglutination method.

Digital material was treated using the Student t criterion.

Analysis of the clinical signs in patients with community-acquired pneumonia demonstrated the expressed changes in patients with severe pneumonia, which manifested in increased tachycardia, respiratory failure, and decreased values of the systolic and diastolic arterial pressures. The temperature reaction in the second group remained during all the observation period.

The patients of the first group revealed segmentary infiltration, whereas the patients of the second group had changes of the pulmonary lobar lesion and polysegmentary changes.

The LPS-SP level in the severe type of pneumonia group exceeded 2.4 times as large as (P < 0.01) the one in the middle-severe type of pneumonia group at admission to the hospital. By the 10th day of observation the LPS-SP concentration in the blood decreased in both groups, remaining significantly high in the second group as compared with the first group (five times as large, P < 0.01), which suggests the continuing stimulation of the LPS bacteria of the monocytic macrophagal link cells and cytokine synthesis induction. Patients of the second group demonstrated hypercytokinemia the most expressed from the first to 10th observation day. At admission the IL-6 and IL-8 concentrations exceeded 13 and 18.4 times as large as (P < 0.05) the values of the first group. The maximal differences in the TNF-α levels between the groups were observed on the third day.

An elevated level of C-reactive protein was registered in patients of both groups. At the same time the C-reactive protein concentration in the patients with severe type pneumonia exceeded four times as large as (P < 0.05) the values of the compared group, which suggested continuous induction of the protein synthesis by cytokines. The LPS-SP, IL-6, IL-8, and TNF-α concentrations in the blood of patients with pneumonia therefore reflect the activity of the systemic inflammatory process and make an important contribution to the development of the whole complex of clinical symptoms causing the state's severity. The analysis of these values' levels will allow one to use them as the laboratory criteria of SIRS appreciation in further studies.