BACKGROUND Mesenchymal stem cells (MSCs) are capable of secreting different substances, including the anti-inflammatory protein TSG-6, which can be useful in the treatment of diseases with inflammatory reactions. The main aim of this study was to evaluate the expression of the TSG-6 gene in MSCs derived from the umbilical cord. For better understanding of the anti-inflammatory properties of MSCs, we additionally assessed the expression of some interleukins (ILs). MATERIAL AND METHODS The study group included 45 patients after delivery, aged from 21 to 46 years; the average patient age was 33 years. MSCs were isolated enzymatically from umbilical cord Wharton's jelly, in vitro cultured, and characterized using flow cytometry; qPCR was performed to assess expression of the studied genes. The expression of genes of a number of pro-inflammatory ILs in MSCs was investigated in relation to the health of patients (coexistence of hypertension), the level of leukocytes, pCO2, and hemoglobin in the blood. RESULTS Our research showed that the expression of the TSG-6 gene in MSCs depends on coexisting diseases in the patient and the biochemical parameters of umbilical cord blood, including the important role of cord blood pH. We found that the levels of IL2 and IL6 expression were correlated with pCO2, and IL6 expression were correlated with pO2. CONCLUSIONS Our study suggests that maternal health status and cord blood biochemical parame-ters could affect the anti-inflammatory properties of MSCs; however, this needs to be confirmed in a future study.