IL12 and IFNγ secretion by donor mononuclear cells in response to host antigens may predict acute GVHD after HSCT

One persistent problem of allogeneic hematopoietic stem cell transplantation (HSCT) is acute graft versus host disease (GVHD). The role of cytokines in the pathogenesis of GVHD has been acknowledged. We aimed, in the current study, to investigate the possibility of prediction of acute GVHD through investigating the pattern of interleukin 12 (IL12) and interferon gamma (IFNγ) production of both patients' origin and donors' origin. A total of 45 patients, receiving allogeneic peripheral blood (PB) stem cells from an identical sibling, were included in the study. Patients' plasma was collected after conditioning, during aplastic phase (representing patients' origin) and after engraftment (representing donors' origin). In addition an aliquot from the graft was used as responders in mixed lymphocyte culture (MLC) for 3 days with patients' mitomycin-treated mononuclear cells as stimulators. Culture supernatant was used for detection of IL12 and IFNγ of donors' origin. Fourteen patients developed acute GVHD. In culture supernatant, IL12 was detectable in 7/14 cases with and in none of 31 cases without acute GVHD (p= <0.001). The corresponding figures for IFNγ were 10/14 and 3/31 with significantly higher IFNγ level in cases with than in cases without acute GVHD (p = 0.001). At engraftment the corresponding figures were 7/14 and 5/31 for IL12 and 11/14 and 7/31 for IFNγ with significantly higher cytokine levels in cases with acute GVHD (p = 0.008 and p = 0.001 respectively). At a cutoff of 0.89 pg/ml, IL12 in culture supernatant may predict acute GVHD with absolute specificity of 100% and a sensitivity of 50%. In conclusion, IL12 and IFNγ of donors' origin not of patients' origin may predict the occurrence of acute GVHD. The MLC model may allow prediction of acute GVHD upfront before conditioning of the patient or mobilization of the donor.