Decreased Expression of PPARγ mRNA in Patients Correlates with aGVHD after Allo-HSCT

Background and objective: Peroxisome proliferator-activated receptor (PPAR)-gamma(γ) is a member of superfamily of nuclear hormone receptors and involved in the lipids metabolism, adipocyte differentiation, atherosclerosis and anti-inflammation. The role of PPARγ in acute graft versus host disease (aGVHD ) remains unclear. In this study, we aimed to investigate the role of PPARγ during aGVHD after allogenic hematopoietic stem cell transplantation (allo-HSCT ).

Methods: 50 patients undering allo-HSCT and 20 healthy controls were enrolled in study. Peripheral blood (PB) of patients 30 days, 60 days, and 90 days were collected after allo-HSCT. We also collected PB samples at aGVHD onset and after aGVHD remission. Peripheral blood mononuclear cells (PBMCs) were isolated for real-time PCR to detect the mRNA expression of PPARγ, IFNγ, IL4, T-bet, GATA3, Foxp3, RORγt .

Results: Expression of PPARγmRNA in healthy controls were significant lower than that in patients after allo-HSCT(P<0.05). At the onset of aGVHD, the expression of PPARγmRNA was significantly lower than that in non-GVHD and increased when remission (P<0.05). PPARγexpression in severe aGVHD (grade 3 to 4) was lower than mild aGVHD (grade 1 to 2) patients (P<0.05). Gender, age, graft type, and the kind of disease showed no significant difference in the aGVHD and non-GVHD patients. The expression of IFNγ and T-bet increased after aGVHD and were negatively correlated with PPARγmRNA expression.

Conclusion: Our findings suggest that low expression of PPARγ is associated with aGVHD occurrence. PPARγ may be a useful indicator to predict aGVHD and follow-up.