Decreased insulin-like growth factor-I receptor sites on circulating mononuclear cells from children with acute leukemia

Insulin-like growth factor-I (IGF-I is a Known mitogen for various cell typ es, including those of the hematopoietic cell system. To study the role of IGF-I in the neoplastic process of leukemia in children, the authors have d etermined the number of IGF-I binding sites on circulating mononuclear cell s of children with acute leukemia as compared to normal children, using bin ding assays. The IGF-I binding sites per cell on peripheral mononuclear cel ls of children with leukemia decreased compared to those of the control gro up (411 +/- 73 and 1334 +/- 227, respectively, p < .001) while their affini ty increased (K-d = 0.14 +/- 0.04 and 0.43 +/- 0.16, respectively, p = .05) . Furthermore, in the patients, the number of the IGF-I binding sites was s ignificantly lower in the subgroup of the peripheral mononuclear cells, whi ch included lymphocytes and monocytes, as compared to their number in the p eripheral blast cells (254 +/- 43.6 and 536 +/- 98.6, respectively, p = .02 ). A significant reduction was found in serum GHBP levels in the patients a s compared to the controls (28.21 +/- 1.93 and 35.83 +/- 2.90, respectively , p = .02), while serum IGF-I and growth hormone levels were similar in pat ient and control groups. These results suggest a possible involvement of IG F-I in childhood acute leukemia, but further studies are needed to establis h whether IGF-I plays a role in this disease.