Monitoring JAK3 mRNA Levels in Patients with GVHD after Allogeneic Hematopoietic Stem Cell Transplantation by Real-Time Quantitative PCR.

Background: Graft-versus-host disease (GVHD) represents a major hurdle impeding the efficacy of allogeneic hematopoietic stem cell transplantation (allo-HSCT). JAK3 plays pivotal roles in the initiation of cytokine-triggered signaling transduction. Recent studies about the murine GVHD model show that targeting JAK3 in donor lymphocytes with a chemical inhibitor such as WHI-P131 may be useful in the prevention of severe GVHD. However, the level of JAK3 expression in patients with GVHD has not been reported. The current study is to develop a reliable and rapid real-time quantitative PCR (Q-PCR) method using Taqman Probe for detecting JAK3 in allo-HSCT recipients.

Methods: 20 patients who received myeloablative-conditioning regimen for hematological malignancies and cyclosporine for GVHD prophylaxis have been investigated in this still ongoing study clinically. One of these patients developed acute GVHD (aGVHD), 9 patients developed chronic GVHD (cGVHD), and 10 patients showed no evidence of GVHD during the first 365 days post-transplant. RNA was extracted from white blood cells and cDNA templates were synthesized using 1μg RNA. The standard curve method was used for relative quantitation of JAK3.

Results: There is a clear trend for a increasing expression of JAK3 in 9 patients with GVHD. Interestingly, a significant decrease of JAK3 gene expression when the severity of GVHD was remission (P=0.04). One of the patient with cGVHD, the level of JAK3 gene expression has no changed before and after treatment. However, these patients post HSCT without GVHD have a comparable level of JAK3 expression before myeloablative conditioning regimen(P>0.05).

Conclusion: Based on our preliminary results, JAK3 mRNA level was obviously correlated with the development of GVHD. Analysis JAK3 mRNA expression may be useful in evaluating GVHD patients with allogeneic stem cell transplantation.