SURGICAL TRAUMA EVOKES A RISE IN THE FREQUENCY OF HEMATOPOIETIC PROGENITOR CELLS AND CYTOKINE LEVELS IN BLOOD-CIRCULATION

Alterations in the mononuclear cell populations in the blood circulati on are among the most characteristic changes after surgical trauma. Th ey reflect changes in the hematopoietic compartment which develop foll owing surgery. The process of mobilization and differentiation of the hematopoietic population is regulated by cytokines known as growth fac tors for stem and progenitor cells (SCF, IL-1, IL-3, IL-6, IL-11, TNF, CSFs). Our question was whether operative trauma resulted in the rele ase of the hematopoietic progenitor cells to the blood circulation and an increase in the blood level of cytokines participating in hematopo iesis. The studies were carried out in patients with chronic cholelith iasis, undergoing elective open cholecystectomy under general anesthes ia. An increase in the frequency of circulating CD34+ hematopoietic pr ogenitor cells was seen between days 3 and 7 after surgery. Moreover, a significant increase in the percentage of immature cells of myeloid lineage (CD13+, CD14+, CD33+) was seen on the 1st and 3rd postoperativ e days. This could be the result of an expansion of the total bone mar row cell number after surgery and a subsequent release of these cells into the blood circulation. The changes in blood cell populations were accompanied by an increase in IL-6 on days 1, 3, and 7 following surg ery, in IL-6sR on days Ia and 14 and in IL-8 on days 1 and 3. No signi ficant changes in IL-1 alpha, IL-1 beta, IL-3 and IL-11 were noted. A small rise in GM-CSF was noted in few patients on the 3rd and 7th post operative days. It is known that IL6 is involved in hematopoiesis. tha t the IL-6-IL-6sR complex may induce both proliferation and differenti ation of hematopoietic progenitor cells and that IL-8 possesses progen itor cell mobilization properties. The appearance of hematopoietic pro genitor cells in the blood following surgery may represent a process f or the expansion of the immune cell pool after trauma and maintaining of the reserves at a certain level.