These biologic changes in response to TACI-Ig are associated with reduced disease scores and prolonged survival in SLE-prone mice[105],[133],[134],[135]. ligand; BAFF, B cell activating factor from the TNF family; BAFF-R, BAFF-receptor; BCMA, B cell maturation antigen; BCR, B cell receptor; BOS, bronchiolitis obliterans syndrome; cGVHD, chronic graftversushost disease; CIDP, chronic-inflammatory demyelinating polyneuropathy; CLL, chronic lymphocytic leukemia; CNS, central nervous system; CVID, common variable immunodeficiency; DCs, dentritic cells; dsDNA, double stranded deoxyribonucleic acid; EBV, EpsteinBarr virus; ECP, extracorporeal AZD8797 photopheresis; FDA, Food and Drug Administration; EULAR, European League Against Rheumatism; GC, germinal center; HIV, human immunodeficiency AZD8797 virus; HSCT, hematopoietic stem cell transplantation; HSPGs, heparan sulfate proteoglycans; ICOS, inducible costimulatory; Ig, immunoglobulin; IFN, interferon; IL, interleukin; LN, lupus nephritis; MMF, mycophenolate mofetil; mRNA, messenger ribonucleic acid; MS, multiple sclerosis; MTX, methotrexate; MVECS, microvacular endothelial cells; MyD88, myeloid AZD8797 differentiation primary response gene 88; MZ, marginal zone; NgR, Nogo-66 receptor; NK, natural killer; NZB, New-Zealand black; NZW, New-Zealand white; PC, plasma cell; PFS, progression-free survival; RF, rheumatoid factor; RSV, respiratory syncytial virus; SAEs, serious adverse events; SCF, stem cell factor; SLE, systemic lupus erythematosus; SLEDAI, SLE Disease Activity Index; SNPs, single nucleotide polymorphisms; SS, Sjgren’s syndrome; TACI, transmembrane activator and cyclophilin ligand interactor; Tg, transgenic; TGF-, transforming growth factor-; Th, T-helper; TLR, toll-like receptor; TNF, tumor Rabbit polyclonal to HYAL2 necrosis factor; Treg, regulatory T cells Keywords:A proliferation inducing ligand (APRIL), Autoimmunity, B cell activating factor from the tumor necrosis factor family (TNF) (BAFF), Cancer, Systemic lupus erythematosus (SLE) == 1. Introduction == The B cell activating factor from the tumor necrosis factor (TNF) family (BAFF; AZD8797 also known as BLyS, TNFSF13B) system has been extensively reviewed since its discovery in 1999[1],[2], particularly in the field of autoimmunity, where BAFF has a crucial role, especially in systemic lupus erythematosus (SLE) (reviewed in Vincent et al.[3]). The role of BAFF on B-lymphocytes and in autoimmunity, and the resulting clinical success in SLE patients, have almost overshadowed the potential role of this system in other immunological fields, such as transplantation/graftversushost disease (GVHD), chronic variable immunodeficiency (CVID), infections and allergy. For instance, BAFF is usually emerging as a critical factor in various hematological and lymphoid cancers. Indeed, a number of translational AZD8797 studies link progression of various malignancies with BAFF’s well-described pro-survival activity, suggesting that the use of BAFF-neutralizing therapies may extend to additional indications, in particular cancer. Furthermore, the BAFF system has recently been described in preeclampsia[4], and the data suggests that both BAFF and APRIL signaling pathways are important for cell viability in the human placenta[5]. This review details the latest results and views on novel functions of the BAFF/APRIL system outside of the autoimmunity arena. However, as the role of BAFF in autoimmunity remains one the most important developments in this decade, this review also provides an update on current clinical trials. == 2. BAFF, APRIL and their receptors == One of the most important paradigm shifts in B-lymphocyte biology in last fifteen years has been the realization that expression of a B cell receptor (BCR) on B cells was important but not enough for survival and maturation. Indeed, BAFF has emerged a critical B cell survival factor without which maturation of B cells does not occur[2]. A proliferation inducting ligand (APRIL; also known as TNFSF13A) was identified as a cell growth stimulator in various cancer cell lines[6]. BAFF and APRIL are produced as type II transmembrane proteins, like many of the TNF family ligands, and are then proteolytically cleaved at a furin protease site and released in a soluble form[7]. BAFF may remain in a membrane-bound form, although processed soluble BAFF is required for B cell homeostasis[8]. In contrast, APRIL is usually cleaved in the Golgi site prior to release, and normally exists in a soluble form only, once outside of the cell of origin[9]. A recently reported exception to this is usually APRIL-, a malignant isoform of APRIL that lacks a furin cleavage site and remains membrane-bound on leukemia cell precursors[10]; another membrane-bound variation is usually TWE-PRIL (TNFSF12TNFSF13), which is a hybrid protein of APRIL and TWEAK (TNF-related weak inducer of apoptosis, TNFSF12) resulting from trans-splicing between their adjacent genes[11]. BAFF is an active ligand as a homotrimer, which is the main form of BAFF found in the circulation[12], however, unlike other TNF family cytokines, a 60-mer form of BAFF has been obtained at.