IgG antibodies cause inflammation and organ damage in autoimmune diseases such as systemic lupus erythematosus (SLE). We investigated the metabolic profile of macrophages isolated from inflamed tissues in immune complex (IC)-associated diseases, including SLE and rheumatoid arthritis, and following IgG Fcγ receptor cross-linking. We found that human and mouse macrophages undergo a switch to glycolysis in response to IgG IC stimulation, mirroring macrophage metabolic changes in inflamed tissue in vivo. This metabolic reprogramming was required to generate a number of proinflammatory mediators, including IL-1β, and was dependent on mTOR and hypoxia-inducible factor (HIF)1α. Inhibition of glycolysis, or genetic depletion of HIF1α, attenuated IgG IC-induced activation of macrophages in vitro, including primary human kidney macrophages. In vivo, glycolysis inhibition led to a reduction in kidney macrophage IL-1β and reduced neutrophil recruitment in a murine model of antibody-mediated nephritis. Together, our data reveal the molecular mechanisms underpinning FcγR-mediated metabolic reprogramming in macrophages and suggest a therapeutic strategy for autoantibody-induced inflammation, including lupus nephritis.

GlaxoSmithKline.

These data raise the possibility that, in high immunologic risk patients undergoing Ai transplantation, the presence of elevated pretransplantation serum BAFF might identify those at increased risk of AMR. BAFF neutralization may be an interesting therapeutic strategy to explore in these patients, particularly because such agents are available and have already been used in the treatment of autoimmunity.

No abstract

Cytomegalovirus (CMV) infection increases the risk of complications after renal transplantation, but the mechanisms controlling donor-derived infection are not adequately characterized. Here, we assessed the risk of clinically significant CMV disease in donor-seropositive, recipient-seropositive (D+R+) renal transplantation and examined recipients' CMV antigen-specific cellular immune responses primed directly by donor cells. In a retrospective cohort of 569 patients administered standardized basiliximab-tacrolimus-mycophenolate-corticosteroid immunosuppressive therapy, CMV disease rates increased in D+R+ serostatus pairings compared with D2R+ pairings (hazard ratio [HR], 2.61; 95% confidence interval [CI], 1.36 to 5.01; P=0.004) and associated with increased donor-recipient HLA mismatch in the D+R+ group (HR [per class 1 mismatch], 1.43; 95% CI, 1.12 to 1.82]; P=0.02). D+R+ and D+R2 transplants in which the donor and recipient differentially expressed at least one HLA class I allele were followed prospectively from the time of transplantation. During the first year after transplantation, four of eight seropositive recipients and one of three seronegative recipients displayed peripheral blood CD8+ T cell responses to CMV presented by recipient-specific HLA. Notably, no recipients mounted responses to CMV presented by donorspecific HLA, despite the detection of CMV antigen expression in all seropositive donor organs examined (n=10), suggesting that the allograft of Class I HLA-mismatched seropositive donors is inaccessible to CD8+ T cell responses. Finally, pretransplant assays of anti-CMV cellular immunity predicted post-transplant CMV replication less accurately in D+R+ pairings than in D2R+ pairings, possibly reflecting in vitro assay specificity for recipient, rather than donor, HLA. These findings are relevant to the clinical management and immunologic understanding of donortransmitted viral infection.

Visual Abstract

An increased understanding of the mechanisms by which the immune system mounts a response to transplanted organs has allowed the development of immunosuppressive regimens that limit acute T-cell-mediated rejection (TCMR). However, the treatment of acute and chronic antibody-mediated rejection (ABMR) in kidney transplants remains sub-optimal. The occurrence and severity of antibody-mediated graft pathology are variable, and genetic polymorphisms that affect the magnitude and nature of the B-cell response, as well as effector functions of antibody, are likely to contribute to such phenotypic variation. Here we review current efforts to understand and quantify the contribution of B cells to renal transplant pathology by studying variation in DNA, mRNA and proteins. Large genetic studies with information on B-cell-specific genetic variants are scarce. At a transcriptomic level, there is evidence that B cells are essential contributors to transplant tolerance and may protect against TCMR and ABMR. In contrast, at the protein level, the detection of donor-specific human leukocyte antigen (HLA) antibodies and an assessment of their capacity to bind complement allow patients of high immunological risk to be identified. Other biomarkers, such as serum B-cell-activating factor (BAFF) or interleukin (IL)-10-producing B cells, may allow this risk stratification to be refined. An increased understanding of the significance of these biomarkers should allow a more accurate assessment of how an individual patient's B cells will impact allograft responses and thereby allow clinicians to adjust therapeutic strategies appropriately.

Variants of SARS-CoV-2 may evade natural and vaccine induced immunity and monoclonal antibody immunotherapeutics. There is an urgent need to know how well antibodies, induced by healthy and Clinically Extremely Vulnerable (CEV) patients, will bind and thus help reduce transmission and severity of infection from variants of concern (VOC). This study determines the cross-reactive binding of serum antibodies obtained prior to and 28 days after a third vaccination in three cohorts; a health care worker cohort who received three doses of Pfizer-BioNtech (PPP), a cohort of CEV patients received two doses of the AstraZeneca-ChAdOx1-nCoV-19 (AAP) vaccine, followed by a third PFZ vaccine and a haemodialysis cohort that had a mixture of two AZ or PFZ vaccines followed by a PFZ booster. Six months post second vaccine there was evidence of antibody waning with 58.9% of individuals in the HD cohort seropositive against Wuhan, 34.4% Delta and 62.2% Omicron strains. For the AAP cohort, equivalent figures were 62.5%, 45.8% and 91.7% and the PPP cohort 92.2%, 90% and 91.1%. Post third dose vaccination there were universal increases in seropositivity and median optical density. For the HD cohort, 98.8% were seropositive to the Wuhan strain, 97.6% against Delta and 100% against Omicron strains. For the PPP and AAP cohorts, 100% were seropositive against all 3 strains. Lastly, we examined the WHO NIBSC 20/136 standard and there was no loss of antibody binding to either VOC. Similarly, a dilution series of Sotrovimab (GSK) found this therapeutic monoclonal antibody bound similarly to all VOC.