ABSTRACT
The aim of this study consisted in underlining the concentrations' evolution in time of two cytokines: IL-1 beta and IFN-gamma, as well as that of RIL-2 (soluble receptor for IL-2), in healthy volunteers. Under normal physiological conditions, these molecules are secreted in small amounts, according to a sequential chronology. Thus, 25 blood samples were carried out from each of the four subjects included in the study, one every 20 minutes, during 8 hours. Concentrations were determined with the ELISA method. Spectral analysis was carried out using the Frequencies Spectrum method (Fourier Transform of a temporal series). This method allows a rhythm search over a milited number of values, in a short interval of time, provided having enough samples. Important variabilities have been observed between all subjects sera, particularly for IL-1 beta (Range (mean +/- SD): 132 +/- 34.6 pg/ml to 250 +/- 17.5 pg/ml, one subject had low values: 2.34 +/- 0.53 pg/ml) and RIL-2 (Range: 677 +/- 175 pg/ml to 1,187 +/- 46.2 pg/ml). Furthermore, ultradian serum variations, characterized by the relation ((Cmax-Cmin)/Cmax) x 100, have been assessed for each subject and each molecule: IL-1 beta (Range: 18.9 to 92.2%), IFN-gamma (Range: 66.3 to 74.2%) and RIL-2 (Range: 11.6 to 86.3%); they might be the manifestation of a periodicity; this hypothesis has been confirmed by the spectral analysis. Thus, the concentrations' variation with time showed a periodicity (Range: 80 mn to 240 mn, the most frequent period was 160 mn (2 h 40 mn)).