Rabbit Anti-Human BAFF monoclonal antibody, clone 0I34M35

Although chronic graft-versus-host disease (CGVHD) is the primary nonrelapse complication of allogeneic transplantation, understanding of its pathogenesis is limited. To identify the main operant pathways across the spectrum of CGVHD, we analyzed gene expression in circulating monocytes, chosen as in situ systemic reporter cells. Microarrays identified two interrelated pathways: 1) IFN-inducible genes, and 2) innate receptors for cellular damage. Corroborating these with multiplex RNA quantitation, we found that multiple IFN-inducible genes (affecting lymphocyte trafficking, differentiation, and Ag presentation) were concurrently upregulated in CGVHD monocytes compared with normal subjects and non-CGVHD control patients. IFN-inducible chemokines were elevated in both lichenoid and sclerotic CGHVD plasma and were linked to CXCR3(+) lymphocyte trafficking. Furthermore, the levels of the IFN-inducible genes CXCL10 and TNFSF13B (BAFF) were correlated at both the gene and the plasma levels, implicating IFN induction as a factor in elevated BAFF levels in CGVHD. In the second pathway, damage-/pathogen-associated molecular pattern receptor genes capable of inducing type I IFN were upregulated. Type I IFN-inducible MxA was expressed in proportion to CGVHD activity in skin, mucosa, and glands, and expression of TLR7 and DDX58 receptor genes correlated with upregulation of type I IFN-inducible genes in monocytes. Finally, in serial analyses after transplant, IFNinducible and damage-response genes were upregulated in monocytes at CGVHD onset and declined upon therapy and resolution in both lichenoid and sclerotic CGVHD patients. This interlocking analysis of IFN-inducible genes, plasma analytes, and tissue immunohistochemistry strongly supports a unifying hypothesis of induction of IFN by innate response to cellular damage as a mechanism for initiation and persistence of CGVHD. The Journal of Immunology, 2016, 197: 3490-3503.

Collagen-induced arthritis (CIA) is an experimental arthritis model used to study the inflammatory processes in this disease and test potential therapeutics. In order to better characterize this model, we conducted the first comprehensive gene expression analysis of rat CIA. To evaluate how closely the rat model reflects human rheumatoid arthritis (RA), we also analysed gene expression in human RA, using genome-wide Affymetrix genearrays. By applying multiple strategies, including comparison of the highest induced genes, expression of immunological-associated genes as well as Ingenuity Pathway Analysis (IPA), we were able to compare the two expression profiles. Among the highest induced genes in RA were several B-cell-associated genes, including immunoglobulins, B-cell markers such as CD20, and cytokines and chemokines that act on B cells such as TNFSF13b/BLyS and CXCL13, none of which was upregulated in CIA. The latter was instead characterized by the upregulation of genes expressed primarily in macrophages and dendritic cells. Of the 22 pathways identified as significant in both diseases by IPA, only three (IL6, chemokine signalling and antigen presentation) were present in both settings. We conclude that there are significant differences in the inflammatory mechanisms between human RA and rat CIA, and that genome-wide comparative gene expression analyses are useful tools to evaluate the relevance of animal models to human disease.