SOLUBLE INTERLEUKIN-2 RECEPTORS IN SERA OF CHILDREN WITH PRIMARY MALIGNANT NEOPLASMS

Purpose: T lymphocyte activation regulates the autocrine type secretio n of interleukin-2, a T cell growth factor and the de novo expression of its cell-surface receptor (IL-2R). Afterwards, a special, truncated form of the IL-2R is secreted into the serum as a soluble molecule. S oluble interleukin-2 receptor (sIL-2R) in serum is a non-specific mark er of common activation of the cellular immune regulation. This study reports the results of an early diagnostic observation of sIL-2R level in the sera of 18 primary solid pediatric malignancies. Patients and Methods: 18 children between the ages of 1 and 12 represented the Stud y Group of solid tumor bearing patients. 12 healthy children between t he ages of 1 and 12 represented the Control group. Concentrations of s IL-2R were detected in the sera of the children employing a double-ant ibody sandwich enzyme-linked immunosorbent assay (T Cell Sciences). Re sults: Control Group concentrations of sIL-2R were in the range of 101 .9 to 255.3 IU/mL with a mean value of 178.6 IU/mL. Serum levels of sI L-2R were markedly elevated in the sera of children with solid tumors (Study Group) to levels between 223.8 IU/mL and 927 IU/mL with a mean value of 575.4 IU/mL. Conclusions: 1) The shedding of cell-surface rec eptors of immunological effector cells is a common physiological mecha nism, 2) Presence of sIL-2R represents a sign of an overall activation of the effector elements of the host's cellular immune system; 3) An increase in the levels of sIL-2R represents an active phase of progres sion; conversely, decreasing levels indicate tumor regression; 4) Seru m levels of sIL-2Rs may represent a useful laboratory parameter in cho osing an efficient anti-cancer therapy. Thus, the level of sIL-2R in c hildhood solid tumor patients has a prognostic significance.