Effect of infliximab on the levels of TNF-alpha and TGF-beta in the whole blood cultures of irradiated patients.

Abstract

TGF-beta is supposed to be the major cytokine responsible for post-radiation fibrosis of healthy tissues and actively modifies post-radiation changes. The growth of TGF-beta level induces the expression of collagen synthesis gene which triggers off the production of fibrosis of hyaline membranes. The main purpose of this study was to discover the way and methods of reducing post-radiation damage of normal tissues and provide an adequate scientific justification for using Infliximab as an effective radio protector in the neoplasm radiotherapy. A group of 97 patients were subjected to the experiment. Randomly selected patients were assigned to 3 groups according to the radiation exposure. The samples of whole blood were suspended in RPMI 1640 growth medium standardized according to the number of leukocytes. Two milliliters of whole blood was taken from each patient immediately before irradiation and 100 microl sample of the blood was placed in wells with 0.8 mg/ml of Infliximab or without the preparation. TGF-beta levels in blood culture without cA2 before irradiation showed continuous rise from 3978 to 8950 pg/ml at the 96th h. In the post irradiated group without cA2, a continuous growth was recorded till the 48th h (from 4758 to 13324 pg/ml at the 24th h) and then a slight decline to 11950 pg/ml at 96th h, respectively. In the cultures with cA2, TGF-beta levels before irradiation showed also the peak value at the 48th h (from 4050 to 7340 pg/ml at the 48th h) and then started to go down (6500 pg/ml at the 72nd h and 5720 pg/ml at the 96th h). In the post-irradiated group, during the first 6 hours, there was a growth from 4717 pg/ml to 7462 pg/ml, and then a paradoxical increase to 16885 pg/ml at the 12th h. From the 12th h the values started to decrease to 6895 pg/ml at the 96th h. The obtained results confirmed the hypothesis of decreasing the TGF-beta expression by inactivating TNF-alpha with a monoclonal antibody (Infliximab) in the patients' whole blood culture in vitro. These observations are a good starting point for further experiments in vitro and in vivo, whose main objective is to reduce post radiation fibrosis.