Global T cell dysregulation in non-autoimmune-prone mice promotes rapid development of BAFF-independent, systemic lupus erythematosus-like autoimmunity

Frequency and predictors for early-achieved lupus low disease activity state in systemic lupus erythematosus patients treated with telitacicept or belimumab: A real-life, single-center observational study

Objective

To collect real-world data regarding the attainment of the early-achieved lupus low disease activity state (LLDAS) in systemic lupus erythematosus (SLE) patients receiving telitacicept or belimumab treatment, and identify factors predictive of target achievement.

Methods

Eighty-seven SLE patients who received telitacicept (N=42) or belimumab (N=45) were retrospectively reviewed in this observational study. Clinical and laboratory data, disease activity assessment, and glucocorticoid dosage were collected for analysis. Achieving LLDAS at least once within 24 weeks post-treatment was considered as early-achieved LLDAS. Multivariate regression was used to assess baseline predictive variables for early-achieved LLDAS. Subgroup analysis and interaction tests were also performed to examine the robustness of the results across different sets of baseline characteristics. Prognostic stratification for early-achieved LLDAS was established based on the identified risk factors.

Results

During the 24-week follow-up period, LLDAS was achieved by at least one time in 49.43% (43/87) of the patients, with sustained achievement through week 24 observed in 36 out of these 43 patients (83.27%). Multivariate analysis revealed that early achievement of LLDAS was particularly observed in patients with higher baseline lymphocyte counts [HR=1.79, 95% CI (1.19-2.67), P=0.005]and serum albumin levels [HR=1.06, 95% CI (1.003-1.12), P=0.039]. Conversely, hematological involvement [HR=0.48, 95% CI (0.24-0.93), P=0.031] predicted lower attainment of early-achieved LLDAS. The use of telitacicept was associated with a reduced risk of failing to attain early achievement of LLDAS [HR=2.55, 95% CI (1.36-4.79), P=0.004]. Subgroup analyses and interaction tests showed a stable relationship between the telitacicept use and LLDAS achievement. The results remained consistent across all subgroup analyses. Significant differences (P<0.001) were observed in the Kaplan-Meier estimates for LLDAS among risk groups based on the number of identified risk factors.

Conclusion

The achievement of LLDAS is attainable in the management of SLE patients undergoing treatment with telitacicept or belimumab in real-life clinical practice. Baseline lymphocyte counts, serum albumin levels, hematological involvement and the use of telitacicept serve as robust predictors for early-achieved LLDAS, helping to identify patients who are likely to benefit on the treatment.

Immune Checkpoint Inhibitors and Lupus Erythematosus

Immune checkpoint inhibitors (ICIs) are the standard of care for a growing number of malignancies. Unfortunately, they are associated with a broad range of unique toxicities that mimic the presentations of primary autoimmune conditions. These adverse events are termed immune-related adverse events (irAEs), of which ICI-lupus erythematosus (ICI-LE) constitutes a small percentage. Our review aims to describe the available literature on ICI-LE and ICI treatment for patients with pre-existing lupus. Most diagnoses of ICI-LE had findings of only cutaneous lupus; four diagnoses of ICI-LE had systemic lupus manifestations. Over 90% (27 of 29) of cases received anti-PD-1/PDL-1 monotherapy, 1 received combination therapy, and 1 received only anti-CTLA-4 treatment. About three-fourths (22 of 29 or 76%) of patients with ICI-lupus were managed with topical steroids, 13 (45%) received hydroxychloroquine, and 10 (34%) required oral corticosteroids. In our case series, none of the patients with pre-existing lupus receiving ICI therapy for cancer had a flare of their lupus, but few had de novo irAE manifestations, all of which were characterized as low-grade. The review of the literature yielded seven ICI-LE flares from a total of 27 patients with pre-existing lupus who received ICI. Most flares were manageable without need for ICI cessation.

Novel human immunomodulatory T cell receptors and their double-edged potential in autoimmunity, cardiovascular disease and cancer

In the last decade, approaches based on T cells and their immunomodulatory receptors have emerged as a solid improvement in treatments for various types of cancer. However, the roles of these molecules in the therapeutic context of autoimmune and cardiovascular diseases are still relatively unexplored. Here, we review the best known and most commonly used immunomodulatory T cell receptors in clinical practice (PD-1 and CTLA-4), along with the rest of the receptors with known functions in animal models, which have great potential as modulators in human pathologies in the medium term. Among these other receptors is the receptor CD69, which has recently been described to be expressed in mouse and human T cells in autoimmune and cardiovascular diseases and cancer. However, inhibition of these receptors individually or in combination by drugs or monoclonal antibodies generates a loss of immunological tolerance and can trigger multiple autoimmune disorders in different organs and immune-related adverse effects. In the coming decades, knowledge on the functions of different immunomodulatory receptors will be pivotal for the development of new and better therapies with less harmful side effects. In this review, we discuss the roles of these receptors in the control of immunity from a perspective focused on therapeutic potential in not only cancer but also autoimmune diseases, such as systemic lupus erythematosus, autoimmune diabetes and rheumatoid arthritis, and cardiovascular diseases, such as atherosclerosis, acute myocardial infarction, and myocarditis.

Association of CTLA4 exon-1 polymorphism with the tumor necrosis factor-α in the risk of systemic lupus erythematosus among South Indians

Cytotoxic T lymphocyte associated-antigen (CTLA4) is a potential negative regulatory molecule of T-cells and associated with several autoimmune diseases. Several reports from different ethnic groups showed that the polymorphisms of the CTLA4 gene have been associated with autoimmune diseases including SLE. Therefore, we aimed to investigate the +49 A/G polymorphism in South Indian SLE patients and its association with disease aetiology and serological markers. A total of 534 samples were genotyped for the +49 A/G polymorphism in exon 1 of the CTLA-4 gene through PCR-RFLP method. We found significant association of genotype and allele frequencies with +49 A/G polymorphism in SLE patients. The frequency of the +49 A/G polymorphism rs231775 'GG' genotype was significantly higher in patients with SLE (12.32%) than those in healthy control subjects (4.6%) (OR: 1.797; 95% CI 1.264-2.554; p=0.001). The frequency of mutant allele 'G' also found to be significantly higher in cases (36.01%) than controls (24.92%) (OR: 1.695, 95% CI: 1.298-2.214, p<0.001). We observed significant increase in serum TNF-α, interferon-α, IL-10 and IL-12 in SLE cases compared to controls. We also found a significant association of serum TNF-α, interferon-α, IL-10 and IL-12 with SLE phenotypes. In addition there was a significant increase in serum TNF-α level in "GG" genotype SLE subjects suggesting that it might play a major role in the advancement of SLE disease.

Immunotherapeutic strategies in autoimmune uveitis

Autoimmune uveitis is an organ-specific disorder characterized by irreversible lesions to the eye that predominantly affect people in their most productive years and is among the leading causes of visual deficit and blindness. Currently available therapies are effective in the treatment of a wide spectrum of uveitis, but are often associated with severe side effects. Here, we review ongoing research with promising immunomodulatory therapeutic strategies, describing their specific features, interactions and the responses triggered by the targeted immune molecules that aim to minimize clinical complications and the likelihood of disease relapse. We first review the main features of the disease, diagnostic tools, and traditional forms of therapy, as well as the animal models predominantly used to understand the pathogenesis and test the novel intervention approaches aiming to control the acute immune and inflammatory responses and to dampen chronic responses. Both exploratory research and clinical trials have targeted either the blockade of effector pathways or of their companion co-stimulatory molecules. Examples of targets are T cell receptors (CD3), their co-stimulatory receptors (CD28, CTLA-4) and corresponding ligands (B7-1 and B7-2, also known as CD80 and CD86), and cytokines like IL-2 and their receptors. Here, we summarize the available evidence on effectiveness of these treatments in human and experimental uveitis and highlight a novel CD28 antagonist monovalent Fab′ antibody, FR104, which has shown preclinical efficacy suppressing effector T cells while enhancing regulatory T cell function and immune tolerance in a humanized graft-versus-host disease (GVHD) mice model and is currently being tested in a mouse autoimmune uveitis model with encouraging results.

Biologic differences between various inhibitors of the BLyS/BAFF pathway: should we expect differences between belimumab and other inhibitors in development?

For the first time in more than 50 years, the US Food and Drug Administration has approved a drug specifically for the treatment of systemic lupus erythematosus (SLE). This drug, belimumab, is a monoclonal antibody that neutralizes the B-cell survival factor, B-lymphocyte stimulator (BLyS). Although belimumab has demonstrated a very favorable safety profile, many SLE patients have failed to clinically improve from belimumab therapy. Three additional BLyS antagonists (atacicept, blisibimod, tabalumab) are currently undergoing clinical testing. These antagonists subtly differ from belimumab in their biologic targets, and each is administered through a route (subcutaneous) that differs from the route through which belimumab is currently delivered (intravenous). Whether these differences will have meaningful consequences for efficacy and safety remains to be determined.

CTLA-4 exon 1 +49A/G polymorphism is associated with renal involvement in pediatric Henoch-Schönlein purpura

BACKGROUND

Henoch-Schönlein purpura (HSP) is a multisystemic vasculitis of unknown etiology. Cytotoxic T-lymphocyte-associated antigen-4 (CTLA-4) and CD28 have been reported to be important candidate genes for conferring susceptibility to autoimmunity. In this study, we investigated the correlation of CTLA-4 and CD28 gene polymorphisms with HSP in children with and without renal involvement.

METHODS

The CTLA-4 exon 1 +49A/G, promoter -318C/T and CD28 IVS3 +17T/C single nucleotide polymorphisms (SNPs) were genotyped in 110 children with HSP and 90 ethnically matched healthy controls through restriction fragment-length polymorphism (RFLP).

RESULTS

The CTLA-4 (+49) GG genotype and G allele (GG + AG genotype) were more common in HSP patients with renal involvement (n = 52) than in HSP patients without renal involvement (n = 58) (P = 0.019 and 0.001, respectively). There were no significant differences in the prevalence of CTLA-4 (+49 A/G), (-318C/T) and CD28 IVS3 (+17 /T/C) polymorphisms between HSP patients and controls.

CONCLUSIONS

Our findings suggest that the CTLA-4 +49 GG genotype and G allele may contribute to increased risk for the development of renal damage in HSP patients.

Concordance of preclinical and clinical pharmacology and toxicology of therapeutic monoclonal antibodies and fusion proteins: cell surface targets

Monoclonal antibodies (mAbs) and fusion proteins directed towards cell surface targets make an important contribution to the treatment of disease. The purpose of this review was to correlate the clinical and preclinical data on the 15 currently approved mAbs and fusion proteins targeted to the cell surface. The principal sources used to gather data were: the peer reviewed Literature; European Medicines Agency 'Scientific Discussions'; and the US Food and Drug Administration 'Pharmacology/Toxicology Reviews' and package inserts (United States Prescribing Information). Data on the 15 approved biopharmaceuticals were included: abatacept; abciximab; alefacept; alemtuzumab; basiliximab; cetuximab; daclizumab; efalizumab; ipilimumab; muromonab; natalizumab; panitumumab; rituximab; tocilizumab; and trastuzumab. For statistical analysis of concordance, data from these 15 were combined with data on the approved mAbs and fusion proteins directed towards soluble targets. Good concordance with human pharmacodynamics was found for mice receiving surrogates or non-human primates (NHPs) receiving the human pharmaceutical. In contrast, there was poor concordance for human pharmacodynamics in genetically deficient mice and for human adverse effects in all three test systems. No evidence that NHPs have superior predictive value was found.

BAFF promotes Th17 cells and aggravates experimental autoimmune encephalomyelitis

Background

BAFF, in addition to promoting B cell survival and differentiation, may affect T cells. The objective of this study was to determine the effect of BAFF on Th17 cell generation and its ramifications for the Th17 cell-driven disease, EAE.

Methodology/Principal Findings

Th17 cells were increased in BAFF-Tg B6 (B6.BTg) mice and decreased in B6.Baff^−/− mice. Th17 cells in B6.Baff^−/− mice bearing a BAFF Tg (B6.Baff^−/−.BTg mice) were identical to those in B6.BTg mice, indicating that membrane BAFF is dispensable for Th17 cell generation as long as soluble BAFF is plentiful. In T + non-T cell criss-cross co-cultures, Th17 cell generation was greatest in cultures containing B6.BTg T cells and lowest in cultures containing B6.Baff^−/− T cells, regardless of the source of non-T cells. In cultures containing only T cells, Th17 cell generation followed an identical pattern. CD4⁺ cell expression of CD126 (IL-6R α chain) was increased in B6.BTg mice and decreased in B6.Baff^−/− mice, and activation of STAT3 following stimulation with IL-6 + TGF-β was also greatest in B6.BTg cells and lowest in B6.Baff^−/− cells. EAE was clinically and pathologically most severe in B6.BTg mice and least severe in B6.Baff^−/− mice and correlated with MOG_35–55 peptide-induced Th17 cell responses.

Conclusions/Significance

Collectively, these findings document a contribution of BAFF to pathogenic Th17 cell responses and suggest that BAFF antagonism may be efficacious in Th17 cell-driven diseases.

Macrophages from lupus-prone MRL mice have a conditional signaling abnormality that leads to dysregulated expression of numerous genes

Macrophages (mϕ) from pre-diseased mice of the major murine inbred models of spontaneous autoimmunity (AI), including multiple lupus-prone strains and the type I diabetes-prone NOD (non-obese diabetic) strain, have identical apoptotic target-dependent abnormalities. This characteristic feature of mϕ from AI-prone mice suggests that abnormal signaling events induced within mϕ following their interaction with apoptotic targets may predispose to AI. Such signaling abnormalities would affect predominantly the processing and presentation of self-antigen (i.e., derived from apoptotic targets), while sparing the processing and presentation of foreign antigen (i.e., derived from non-apoptotic sources). Here, we used DNA microarrays to test the hypothesis that mϕ from AI-prone mice (MRL/MpJ [MRL/+] or MRL/MpJ-Tnfrsf6 ( lpr ) [MRL/lpr]) differentially express multiple genes in comparison to non-AI mϕ (BALB/c), but do so in a largely apoptotic cell-dependent manner. Mϕ were stimulated with lipopolysaccharide, a potent innate stimulus, in the presence or absence of serum (an experimental surrogate for apoptotic targets). In accord with our hypothesis, the number of genes differentially expressed by MRL mϕ was significantly increased in the presence vs. the absence of serum, the apoptotic target surrogate (n = 401 vs. n = 201). Notably, for genes differentially expressed by MRL mϕ in the presence of serum, serum-free culture normalized their expression to a level statistically indistinguishable from that by non-AI mϕ. Comparisons of mϕ from AI-prone NOD and non-AI C57BL/6 mice corroborated these findings. Together, these data support the hypothesis that mϕ from MRL and other AI-prone mice are characterized by a conditional abnormality elicited by serum lipids or apoptotic targets.

Abnormal CTLA-4 function in T cells from patients with systemic lupus erythematosus

CTLA-4 is a critical gatekeeper of T-cell activation and immunological tolerance and has been implicated in patients with a variety of autoimmune diseases through genetic association. Since T cells from patients with the autoimmune disease systemic lupus erythematosus (SLE) display a characteristic hyperactive phenotype, we investigated the function of CTLA-4 in SLE. Our results reveal increased CTLA-4 expression in FOXP3(-) responder T cells from patients with SLE compared with other autoimmune rheumatic diseases and healthy controls. However, CTLA-4 was unable to regulate T-cell proliferation, lipid microdomain formation and phosphorylation of TCR-zeta following CD3/CD28 co-stimulation, in contrast to healthy T cells. Although lupus T cells responded in vitro to CD3/CD28 co-stimulation, there was no parallel increase in CTLA-4 expression, which would normally provide a break on T-cell proliferation. These defects were associated with exclusion of CTLA-4 from lipid microdomains providing an anatomical basis for its loss of function. Collectively our data identify CTLA-4 dysfunction as a potential cause for abnormal T-cell activation in patients with SLE, which could be targeted for therapy.