CTLA-4 polymorphisms are associated with treatment outcomes of patients with multiple myeloma receiving bortezomib-based regimens.

Single-nucleotide polymorphisms (SNPs) of cytotoxic T lymphocyte antigen-4 (CTLA-4) are important risk factors associated with autoimmune diseases and malignancies. This study explored the association of CTLA-4SNPs with the development of myeloma and evaluated the outcome of patients receiving bortezomib-based regimens in relation to CTLA-4SNPs. Peripheral blood samples from 86 patients with multiple myeloma (MM) and 154 healthy controls were obtained to investigate CTLA4 polymorphisms. Five SNP genotypes of CTLA-4, namely, -1772 (rs733618), -1661 (rs4553808), -318 (rs5742909), CT60 (rs3087243), and +49 (rs231775), were evaluated through TaqMan SNP genotyping assays (Applied Biosystems). Some of the CTLA-4 polymorphisms displayed frequencies that vary among ethnic groups. Kaplan-Meier analysis revealed that patients with rs733618 GG showed a significantly lower disease-free survival (0 vs. 57.4%, P = 0.020) and overall survival (46.3 vs. 83.3%, P = 0.026) than those with GA+AA following bortezomib-based therapy. Multivariate analyses showed that rs733618 GG was a risk factor for OS (HR = 0.012; 95% CI = 0.001-0.199; P = 0.002). The incidence of nonhematologic grade 3/4 adverse events significantly increased in the rs4553808 GG+GA group compared with that in the AA group (P = 0.036). CTLA-4 rs733618 GG reduced the progression-free survival and the overall survival of patients with MM who received bortezomib-based therapy. Information regarding CTLA-4 polymorphisms and haplotypes may be used to improve MM therapy. Future studies must determine the precise effect of CTLA-4 polymorphisms and haplotypes on MM therapy outcomes by using different cohorts with a large number of subjects.

Recipient-donor KIR ligand matching prevents CMV reactivation post-haploidentical T cell-replete transplantation.

Licensed natural killer (NK) cells have been demonstrated to have anti-cytomegalovirus (CMV) activity. We prospectively analysed the human leucocyte antigen typing of donor-recipient pairs and the killer cell immunoglobulin-like receptor (KIR) typing of donors for 180 leukaemia patients to assess the predictive roles of licensed NK cells on CMV reactivation post-T-cell-replete haploidentical stem cell transplantation. Multivariate analysis showed that donor-recipient KIR ligand graft-versus-host or host-versus-graft direction mismatch was associated with increased refractory CMV infection (Hazard ratio = 2·556, 95% confidence interval, 1·377-4·744, P = 0·003) post-transplantation. Donor-recipient KIR ligand matching decreased CMV reactivation [51·65% (46·67, 56·62%) vs. 75·28% (70·87, 79·69%), P = 0·012], refractory CMV infection [17·58% (13·77, 21·40%) vs. 35·96% (31·09, 40·82%), P = 0·004] and CMV disease [3·30% (1·51, 5·08%) vs. 11·24% (8·04, 14·43%), P = 0·024] by day 100 post-transplantation. In addition, the percentage of γ-interferon expression on donor-derived NK cells was significantly higher in the recipients among the recipient-donor pairs with a KIR ligand match compared with that in the recipients among the pairs with a KIR ligand graft-versus-host or host-versus-graft direction mismatch on days 30 and 100 post-transplantation (P = 0·036 and 0·047, respectively). These findings have suggested that donor-recipient KIR ligand matching might promote the NK cell licensing process, thereby increasing NK cell-mediated protection against CMV reactivation.

Poor CMV-specific CD8+ T central memory subset recovery at early stage post-HSCT associates with refractory and recurrent CMV reactivation.

OBJECTIVES: Refractory and recurrent cytomegalovirus (CMV) reactivation were independent risk factors of CMV disease and transplant-related mortality post allogeneic hematopoietic stem cell transplantation (allo-HSCT). Our aims were to identify the recovery of CMV-specific CD8+ T cells with a central memory phenotype (TCM) associated with refractory and recurrent CMV reactivation. METHOD: We analyzed findings in a prospective study comprising (n = 107) post allo-HSCT. CMV-specific CD8+ T cells were determined using HLA class I pentamers together with extended phenotypic analyses. RESULT: The patients with lower level of CMV-specific CD8+ TCM at day 30 post-HSCT had an increased risk of refractory and recurrent CMV (68.5%) comparing with the higher one (13.2%) (p < 0.001) and poorer long term CMV-specific CD8+ T cell reconstitution post-HSCT (p = 0.026). Multivariate analysis revealed that CMV-specific CD8+ TCM at day 30 was an independent prognostic factor for refractory and recurrent reactivation (p = 0.002). CONCLUSION: The CMV-specific CD8+ TCM subset at day 30 post-HSCT is associated with CMV-specific T cell immunity recovery as well as the refractory and recurrent CMV reactivation post-HSCT.

Increased Type 1 Immune Response in the Bone Marrow Immune Microenvironment of Patients with Poor Graft Function after Allogeneic Hematopoietic Stem Cell Transplantation.

Poor graft function (PGF) is a severe complication after allogeneic hematopoietic stem cell transplantation (allo-HSCT). The question of whether the bone marrow (BM) immune microenvironment is involved in the pathogenesis of PGF remains unresolved. In total, 10 patients with PGF, 30 matched patients with good graft function after allo-HSCT, and 15 healthy donors were enrolled in this nested case-control study. The Th1, Th2, Tc1, Tc2, and active phenotypes were analyzed by flow cytometry. IFN-γ and IL-4 levels in BM plasma were evaluated using cytometric beads assay. Relative to other subjects, patients with PGF had significantly higher proportions of stimulated CD4(+) and CD8(+) T cells that produced IFN-γ (Th1 and Tc1 cells) but notably decreased proportions of IL-4-producing T cells (Th2 and Tc2 cells), resulting in a shift of the IFN-γ/IL-4 ratio towards a type 1 response and an elevated percentage of activated CD8(+) T cells. Changes in IFN-γ and IL-4 levels in BM plasma were consistent with the cellular results. Our results suggest that dysregulated T cell responses may contribute to the occurrence of PGF after HSCT.

Rat and human STINGs profile similarly towards anticancer/antiviral compounds.

Cyclic dinucleotides (CDNs) and antitumor/antiviral agents (DMXAA and CMA) trigger STING-dependent innate immunity activation. Accumulative evidences have showed that DMXAA and CMA selectively activate mouse, but not human STING signaling. The mechanism underlying this species selectivity remains poorly understood. In this report, we have shown that human and rat STINGs display more similar signaling profiles toward DMXAA and CMA than that of human and mouse STINGs, suggesting that rat is more suitable for preclinical testing of STING-targeted drugs. We have also determined the crystal structures of both apo rat STING and its complex with cyclic GMP-AMP with 2'5' and 3'5' phosphodiester linkage (2'3'-cGAMP), a human endogenous CDN. Structure-guided biochemical analysis also revealed the functional importance of the connecting loop (A140-N152) between membrane and cytosolic domains in STING activation. Taken together, these findings reveal that rat STING is more closely related to human STING in terms of substrate preference, serving as a foundation for the development of STING-targeted drugs.

The structural basis for the sensing and binding of cyclic di-GMP by STING.

STING (stimulator of interferon genes) is an essential signaling adaptor that mediates cytokine production in response to microbial invasion by directly sensing bacterial secondary messengers such as the cyclic dinucleotide bis-(3'-5')-cyclic dimeric GMP (c-di-GMP). STING's structure and its binding mechanism to cyclic dinucleotides were unknown. We report here the crystal structures of the STING cytoplasmic domain and its complex with c-di-GMP, thus providing the structural basis for understanding STING function.

REUL is a novel E3 ubiquitin ligase and stimulator of retinoic-acid-inducible gene-I.

RIG-I and MDA5 are cytoplasmic sensors that recognize different species of viral RNAs, leads to activation of the transcription factors IRF3 and NF-kappaB, which collaborate to induce type I interferons. In this study, we identified REUL, a RING-finger protein, as a specific RIG-I-interacting protein. REUL was associated with RIG-I, but not MDA5, through its PRY and SPRY domains. Overexpression of REUL potently potentiated RIG-I-, but not MDA5-mediated downstream signalling and antiviral activity. In contrast, the RING domain deletion mutant of REUL suppressed Sendai virus (SV)-induced, but not cytoplasmic polyI:C-induced activation of IFN-beta promoter. Knockdown of endogenous REUL by RNAi inhibited SV-triggered IFN-beta expression, and also increased VSV replication. Full-length RIG-I, but not the CARD domain deletion mutant of RIG-I, underwent ubiquitination induced by REUL. The Lys 154, 164, and 172 residues of the RIG-I CARD domain were critical for efficient REUL-mediated ubiquitination, as well as the ability of RIG-I to induce activation of IFN-beta promoter. These findings suggest that REUL is an E3 ubiquitin ligase of RIG-I and specifically stimulates RIG-I-mediated innate antiviral activity.