THE IMPORTANT BALANCE BETWEEN CYTOKINES DERIVED FROM TYPE-1 AND TYPE-2 HELPER T-CELLS IN THE CONTROL OF GRAFT-VERSUS-HOST DISEASE

We have investigated cytokine mRNA expression in the peripheral blood mononuclear cells of 20 patients who received allogeneic hematopoietic stem cell transplants to assess the cytokine network after transplant ation, IL-4 mRNA expression decreased in five of five (100%) patients with greater than or equal to grade III (severe) acute GVHD and increa sed in 10 of 22 (45%) patients without severe GVHD. In contrast, IL-12 mRNA expression increased in two of two (100%) patients with severe G VHD, but increased in only six of 18 (33%) patients without severe GVH D, Furthermore, IL-10 and/or IL-13 mRNA expression increased in 19 of 22 (86%) patients without severe GVHD, but increased in only one of th ree (33%) patients with severe GVHD, In patients with allogeneic PBSCT who had severe acute GVHD, the cytokine mRNA expression in patients w ith allogeneic PBSCT, who had no severe GVHD, showed a similar pattern to that in patients with allogeneic BMT. IL-4 mRNA expression increas ed in three of five (60%) patients and IL-10 and/or IL-13 mRNA express ion increased in five of five (100%) patients, In contrast, IL-12 mRNA expression increased in only one of three (33%) patients, Serum IL-4 concentration in allogeneic PBSCT patients in the early engraftment ph ase was relatively high, while serum IL-12 concentration was low, Thes e findings suggest that severe GVHD may be related to the cytokine imb alance between type 1 helper T (Th1) cells and type 2 helper T (Th2) c ells.