Expression of SOCS1 and SOCS3 genes in human graft-versus-host disease after allogeneic hematopoietic stem cell transplantation

Background: Suppressor of cytokine signaling genes (SOCS) are regarded as pivotal negative feedback regulators of cytokine signals, including the interferon-gamma (IFN-γ), granulocyte-colony stimulating factor, and interleukin families, released by T cells. A detailed understanding of the involvement of SOCS genes in graft-versus-host disease (GVHD) is critical to effectively manage GVHD, yet their expression patterns among recipients remain largely unexplored. Methods: Expression levels of SOCS1 and SOCS3 were determined by real-time quantitative reverse transcription PCR (qRT-PCR) in patients with acute GVHD (aGVHD) and chronic GVHD (cGVHD), in a severity-dependent manner, after allogeneic hematopoietic stem cell transplantation (HSCT). A total of 71 recipients with AML (N=40), ALL (N=12), myelodysplastic syndromes (MDS; N=10), chronic myelogenous leukemia (CML; N=2), severe aplastic anemia (SAA; N=5), or others (N=2), who received allogeneic HSCT from human leukocyte antigen-identical siblings or unrelated donors between 2009 and 2011, were included in the present study. Results: Overall, the expression levels of SOCS1 decreased in recipients with grade II to IV aGVHD and cGVHD when compared to normal donors and non-GVHD recipients. Interestingly, the expressions of SOCS1 decreased significantly more in cGVHD than in aGVHD recipients (P=0.0091). In contrast, SOCS3 expressions were similarly reduced in all the recipients. Conclusion: This is the first study to show that SOCS1 and SOCS3 are differentially expressed in recipients following allogeneic HSCT, suggesting a prognostic correlation between SOCS genes and the development of GVHD. This result provides a new platform to study GVHD immunobiology and potential diagnostic and therapeutic targets for GVHD.