IL-15 in the culture supernatants of PMN and PBMC and the serum of patients with Lyme disease.

PURPOSE The aim of this study was to estimate the production of interleukin-15 (IL-15) by neutrophils (PMNs) and peripheral blood mononuclear cells (PBMC) confronted with the serum levels of IL-15 in patients with Lyme disease. MATERIAL AND METHODS PMN and PBMC were isolated from heparinized whole blood of patients. The cells were incubated for 18 hs at 37 degrees C in a humidified incubator with 5% CO2. After 18 hs incubation, supernatant was removed and assessed for IL-15 using ELISA kits. RESULTS The results obtained showed significant increase in the ability of patient's PMNs and peripheral blood mononuclear cells (PBMC) to release IL-15. Although PBMC produced higher concentrations of IL-15 than PMN, the quantitative dominance of PMN in the peripheral blood suggest a significant role for these cells in the defense reactions controlled by this cytokine. Similar changes in the secretion of IL-15 by PMN and PBMC in patient group may be caused by the same regulatory mechanisms which influence the functional abnormalities of the cells examined. CONCLUSIONS A change in the ability of PMN and PBMC to release IL-15 may have various implications for the cellular and humoral response to the Borrelia burgdorferi (B.b.) infection in patients with Lyme disease.