In vitro inhibitory effect of CD8+ cells from patients with aplastic anemia on normal CFU-Mk growth is blocked by cimetidine

AIM: To investigate the effect of CD8+ cells from aplastic anemia (AA) patients and its histamine type II (H2) receptors on the growth of normal CFU-Mk. METHODS: The effects of CD8+ cells and/or cimetidine, on normal human CFU-Mk growth were studied by using CFU-Mk assay. RESULTS: The CD8+ cells from the perpheral blood of AA patients significantly suppressed the growth of normal allogeneic CFU-Mk. This inhibitory effect was blocked by cimetidine at concentration of 1.0×10-5 mol/L. 1.0×10-5 mol/L cimitidine alone didn't inhibit the growth of normal CFU-Mk. CONCLUSION: H2 receptor antagonist cimitidine abolishes the suppressive effect of AA patients CD8+ cells on the growth of normal CFU-Mk.