Expansion of CD4+CD8+ double-positive T cells in rheumatoid arthritis patients is associated with erosive disease.

OBJECTIVES: CD4+CD8+ double-positive (DP) T cells are expanded in the peripheral blood of a subset of patients with RA. This study examines the clinical significance of DP T cells in RA. METHODS: In 70 RA patients, DP T cells were measured by flow cytometry. Clinical data were obtained, and hand and feet radiographs were scored according to the Sharp/van der Heijde (SvdH) method. The association between DP T cell frequency and erosive joint destruction was analysed by correlation and multiple logistic regression analysis. RESULTS: Nineteen RA patients (27.1%) displayed increased DP T cell frequencies, which correlated with age (r = 0.288, P =0.016). Expansion of DP T cells was associated with the occurrence of erosions (94,7% vs 43,1%, P <0.001), with a higher SvdH joint damage score (24.5 vs 6, P =0.008) and with more frequent use of biologic or targeted-synthetic DMARDs (68.4% vs 38%, P =0.02). In patients with non-erosive disease, DP T cell frequencies correlated with the joint space narrowing score (n = 28, r = 0.44, P =0.02). Logistic regression revealed DP T cells to be associated with erosive disease (OR 1.90, P <0.05). CONCLUSION: Expansion of DP T cells is associated with joint damage and frequent escalation of therapy, possibly suggesting a contribution to more severe RA.

Humoral and cellular response to COVID-19 vaccination in patients with autoimmune inflammatory rheumatic diseases under real-life conditions.

OBJECTIVES: Successful vaccination is key to overcoming the COVID-19 pandemic. Immunosuppressive medication is known to potentially compromise vaccination responses, and expansion of our knowledge on vaccination efficacy in patients with autoimmune inflammatory rheumatic diseases (AIIRD) is therefore of utmost importance. METHODS: We conducted a single-centre observational study and evaluated the efficacy of approved COVID-19 vaccines in 303 adult AIIRD patients. Serum levels of IgG antibodies against the S1 subunit of SARS-CoV-2 spike proteins (anti-S IgG) were measured at least two weeks after vaccination. In a subgroup of patients without humoral response, T-cell responses were determined using an interferon-γ gamma release assay. RESULTS: Overall seropositivity rate was 78.5% and was significantly lower in patients under immunosuppressive therapy (75.7 vs 93.2%, P = 0.009). No difference regarding the vaccination type was observed. Glucocorticoids, mycophenolate-mofetil, TNF inhibitors, tocilizumab, abatacept and rituximab were all associated with non-response after proper vaccination. The risk was highest under RTX therapy (OR 0.004, 95% CI 0.001, 0.023, P < 0.0001). A strong negative correlation was observed between time since vaccination with an mRNA vaccine and anti-S antibody levels (r=-0.6149, P < 0.0001). In patients without humoral response, a T-cell response was found in 50%. CONCLUSIONS: COVID-19 vaccination in patients with AIIRD is effective using any approved vaccine. Humoral response might be impaired depending on the individual immunosuppressive medication. The risk of non-response is highest under rituximab therapy. Anti-S IgG antibody levels wane over time after mRNA vaccination. Importantly, 50% of humoral non-responders showed a T-cellular response, suggesting T-cell-mediated protection to a certain extent.

PIR-B expressing CD8+ T cells exhibit features of Tc1 and Tc17 in SKG mice.

OBJECTIVE: In autoimmune arthritis, TCR signalling is attenuated by peripheral tolerance mechanisms. We have described previously a population of inhibitory receptor LIR-1 expressing autoreactive CD8+ T cells in rheumatoid arthritis. Here, we investigated the role of CD8+ T cells in murine autoimmune arthritis by analysing their expression of the mouse orthologue of LIR-1, PIR-B. METHODS: Frequencies of PIR-B+CD8+ T cells were determined in the SKG arthritis model. The phenotype of those cells was determined ex vivo by FACS and functionality was investigated by means of cytokine production and cytolytic potential upon activation in vitro. RESULTS: SKG mice, under non-SPF (specific pathogen-free) conditions with clinical symptoms of arthritis, were found to harbour significantly increased frequencies of PIR-B+CD8+ T cells. Those cells showed a pro-inflammatory phenotype with preferential production of IL-17 and IFN-γ. The frequency of those cells correlated inversely with the arthritis score, indicating that they might represent autoreactive, but functionally inhibited, CD8+ T cells. CONCLUSION: PIR-B+CD8+ T cells from SKG mice show a cytotoxic and pro-inflammatory phenotype. Inhibition of CD8+ T cell autoreactivity by PIR-B/LIR-1 receptor signalling might be a counter-regulatory mechanism to curb autoreactivity and arthritis.

Autoimmune arthritis induces paired immunoglobulin-like receptor B expression on CD4+ T cells from SKG mice.

The chronic, destructive autoimmune arthritis in SKG mice, which closely resembles human rheumatoid arthritis, is the result of self-reactive T cells escaping thymic deletion. Since the inhibitory receptor LIR-1 is up-regulated on auto-reactive T cells in human rheumatoid arthritis, the role of its murine ortholog PIR-B was investigated. Peripheral CD4+ T cells from SKG mice were found to frequently express PIR-B, and this population produces more frequently IL-17 upon in vitro stimulation compared to PIR-B- cells. A much larger fraction of PIR-B+ T cells, however, was found to secret no IL-17, but IFN-γ. With regards to the clinical course of the disease, high frequencies of PIR-B+ CD4+ T cells were found to be associated with a milder course of arthritis, suggesting that the net effect of PIR-B expression is suppression of autoreactive T cells. Our results indicate that overexpression of PIR-B on IL-17-producing SKG CD4+ T cells might represent an effective counter-regulatory mechanism against the destructive potential of those cells. More importantly, a major population of PIR-B+ T cells in SKG mice appears to play an inhibitory role by way of their IFN-γ production, since high frequencies of those cells ameliorate the disease.

Tumor necrosis factor receptor type I expression of CD4+ T cells in rheumatoid arthritis enables them to follow tumor necrosis factor gradients into the rheumatoid synovium.

OBJECTIVE: The cytokine tumor necrosis factor (TNF) plays a central role in the pathogenesis of rheumatoid arthritis (RA), but its disease-specific effector mechanisms have not been fully elucidated. This study was undertaken to investigate the role of TNF in T cell accumulation and migration in the synovitic joints of RA patients. METHODS: Vital tissue sections from rheumatoid synovium were generated using a horizontally oscillating microtome and were coincubated with fluorescence-labeled CD4+ T cells. Migration was detected by fluorescence and confocal microscopy. Migrating T cells were recovered from the tissue and analyzed for phenotype. Chemotaxis of CD4+ T cells from RA patients in response to increasing concentrations of TNF was analyzed in Transwell experiments. RESULTS: CD4+ T cells from RA patients migrated into the tissue sections in significantly higher numbers than T cells from healthy controls. Migrating CD4+ T cells differed from nonmigrating ones in their increased expression of TNF receptor type I (TNFRI), which was expressed on a fraction of circulating CD4+ T cells from RA patients, but not from controls. CD4+ T cells from the peripheral blood of RA patients were also found to migrate along TNF concentration gradients ex vivo. Accordingly, blockade of either TNF or TNFRI nearly abrogated in vitro T cell migration in synovial tissue. CONCLUSION: Our findings indicate that the interaction of TNF with TNFRI is pivotal for T cell migration in synovial tissue in vitro, and thereby suggest a relevant role of the cytokine for in vivo T cell trafficking to synovitic joints.

CD4+CD8αlow T cells in rheumatoid arthritis are clonally expanded and dependent on co-stimulation.

OBJECTIVES: CD4+CD8+ T cells are increased in patients with rheumatoid arthritis (RA). They are not only associated with joint erosions in established disease, but are also present in the pre-clinical stages of RA. This study aims to further investigate their expansion in the context of T cell clonality in patients with RA, as well as their responsiveness to T cell targeted treatment. METHODS: Single-cell-(sc)RNA- and scTCR-sequencing data were used to determine co-receptor expression and T cell receptor sequences to assess clonality of CD4+CD8+ T cells in RA (n=3) patients and healthy controls (n=2). Peripheral CD4+CD8+ T cells and their subpopulations were measured in patients with RA (n=53), PsA (n=52) and healthy donors (n=50) using flow cytometry. In addition, changes in CD4+CD8+ T cell frequency were prospectively followed in RA patients receiving therapy with abatacept for 12 weeks. RESULTS: We observed an increase of CD4+ T cells expressing CD8α in RA patients, both in comparison to PsA patients and to healthy controls. Clonality analysis revealed, that these CD4+CD8αlow T cells are part of large T cell clones, which cluster separately from CD4+CD8- T cell clones in the scRNA-seq gene expression analysis. Treatment with abatacept significantly reduced the frequency of peripheral CD4+CD8αlow T cells, and this was linked to reduction in disease activity. CONCLUSION: In RA, clonal expansion of CD4+ T cell clones culminates in the emergence of peripheral CD4+CD8αlow T cells, which are associated with disease activity and diminished upon abatacept treatment, and which could contribute to disease pathogenesis.

Glucose-oxygen deprivation constrains HMGCR function and Rac1 prenylation and activates the NLRP3 inflammasome in human monocytes.

Hypoxia and low glucose abundance often occur simultaneously at sites of inflammation. In monocytes and macrophages, glucose-oxygen deprivation stimulates the assembly of the NLRP3 inflammasome to generate the proinflammatory cytokine IL-1ß. We found that concomitant glucose deprivation and hypoxia activated the NLRP3 inflammasome by constraining the function of HMG-CoA reductase (HMGCR), the rate-limiting enzyme of the mevalonate kinase pathway. HMGCR is involved in the synthesis of geranylgeranyl pyrophosphate (GGPP), which is required for the prenylation and lipid membrane integration of proteins. Under glucose-oxygen deprivation, GGPP synthesis was decreased, leading to reduced prenylation of the small GTPase Rac1, increased binding of nonprenylated Rac1 to the scaffolding protein IQGAP1, and enhanced activation of the NLRP3 inflammasome. In response to restricted oxygen and glucose supply, patient monocytes with a compromised mevalonate pathway due to mevalonate kinase deficiency or Muckle-Wells syndrome released more IL-1ß than did control monocytes. Thus, reduced GGPP synthesis due to inhibition of HMGCR under glucose-oxygen deprivation results in proinflammatory innate responses, which are normally kept in check by the prenylation of Rac1. We suggest that this mechanism is also active in inflammatory autoimmune conditions.

The CD14(bright) CD16+ monocyte subset is expanded in rheumatoid arthritis and promotes expansion of the Th17 cell population.

OBJECTIVE: Circulating monocytes contain a subpopulation of CD14+CD16+ cells; this subpopulation of cells has been described to be proinflammatory and to have an increased frequency in rheumatoid arthritis (RA). New evidence suggests that this subpopulation can be further subdivided into CD14(dim) CD16+ and CD14(bright) CD16+ cells. The aim of this study was to determine which of the two CD16+ monocyte subpopulations is expanded in patients with RA and to investigate their possible role in disease pathogenesis. METHODS: The frequencies of monocyte subpopulations in the peripheral blood of healthy donors and patients with RA were determined by flow cytometry. Monocyte subpopulations were sorted and cocultured with CD4+ T cells. Cytokines were determined in the supernatant, and Th17 cell frequencies were measured by flow cytometry. RESULTS: In comparison with the other monocyte subpopulations, CD14(bright) CD16+ cells showed higher HLA-DR and CCR5 expression and responded with higher tumor necrosis factor production to direct cell contact with preactivated T cells. They were observed at increased frequencies in the peripheral blood of patients with RA, while CD14(dim) CD16+ monocyte frequencies were not increased. CD14(bright) CD16+ cells were extremely potent inducers of Th17 cell expansion in vitro. Their frequency in the peripheral blood of patients with RA correlated closely with Th17 cell frequencies determined ex vivo. CONCLUSION: This study is the first to provide a link between the increased frequency of the CD14(bright) CD16+ monocyte subpopulation in RA and the expansion of Th17 cells, which are likely to have a role in the pathogenesis of autoimmunity.

Association of anticytomegalovirus seropositivity with more severe joint destruction and more frequent joint surgery in rheumatoid arthritis.

OBJECTIVE: Expansion of autoreactive CD4+CD28(null) T cells is associated with extraarticular disease manifestations, including rheumatoid vasculitis, and it has recently been demonstrated that expansion of these T cells is associated with anticytomegalovirus (anti-CMV) seropositivity. This study was undertaken to investigate a possible link between latent CMV infection and rheumatoid arthritis (RA). METHODS: In a retrospective analysis, anti-CMV antibodies and clinical, serologic, and radiologic parameters of joint destruction were examined in 202 RA patients and 272 healthy controls. In addition, frequencies of CD4+CD28(null) T cells; concentrations of the cytokines monocyte chemotactic protein 1 (MCP-1), interferon-α (IFNα), and IFN-inducible protein 10; and anti-CMV-specific T cell responses were analyzed in RA patients. RESULTS: Overall, no significant difference in the frequency of anti-CMV seropositivity between RA patients and healthy controls was observed. Among individuals older than age 55 years, however, anti-CMV IgG antibodies were significantly more frequent in RA patients than controls (65.3% and 54.7%, respectively; P = 0.05). Anti-CMV seropositivity in RA patients was associated with an increased frequency of CD4+CD28(null) T cells and increased serum concentrations of MCP-1. The frequency of anti-CMV-specific CD4+ T cells producing IFNγ was increased in RA patients compared to controls. Most importantly, anti-CMV-seropositive RA patients showed radiographic evidence of more advanced joint destruction and had increased frequencies of joint-related surgical procedures, indicating more severe joint disease. CONCLUSION: Our findings indicate that latent CMV infection aggravates the clinical course of RA and is associated with increased frequencies of CD4+CD28(null) T cells and of CMV-specific IFNγ-secreting CD4+ T cells.

IL-10 Induced by mTNF Crosslinking-Mediated Reverse Signaling in a Whole Blood Assay Is Predictive of Response to TNFi Therapy in Rheumatoid Arthritis.

(1) Background: To date, the response of patients with rheumatoid arthritis (RA) to the various biologic DMARD available cannot be predicted due to a lack of reliable biomarkers. Based on our preliminary work on tmTNF reverse signaling, we developed a whole-blood assay measuring tmTNF crosslinking-induced IL-10 production to predict the response to TNF inhibitor (TNFi) therapy. (2) Methods: This prospective study included patients with active RA. Depending on the clinical judgment of the attending rheumatologist, either therapy with a TNF or JAK inhibitor was initiated. Clinical parameters and blood samples were obtained at baseline and after 8 weeks of therapy. The blood samples were collected using a newly developed whole-blood assay based on the principle of tmTNF reverse signalling. Subsequently, IL-10 was measured via enzyme-linked immunosorbent assay (ELISA) technique. (3) Results: 63 patients with RA were enrolled. In fifteen patients, TNFi therapy was initiated, while eight patients started a JAKi treatment. The cross-sectional analysis of all patients showed a positive correlation between tmTNF crosslinking-induced IL-10 and parameters of disease activity (CRP [r = 0.4091, p = 0.0009], DAS28 [r = 0.3303, p = 0.0082]) at baseline. In the TNFi treatment study, IL-10 was found to be significantly higher in EULAR responders than in non-responders (p = 0.0033). After initiation of JAKi treatment, in contrast, IL-10 induction was not linked to response. Longitudinal analysis of the TNFi-treated patients revealed IL-10 to decrease in responders (p = 0.04), but not in non-responders after 8 weeks of therapy. Of importance, the IL-10 production at baseline correlated inversely with TNFi response determined by ΔDAS28 in patients with TNFi treatment (r = -0.5299, p = 0.0422) while no such link was observed under JAKi therapy (p = 0.22). Receiver operation characteristics (ROC) analysis demonstrated a high performance of tmTNF/crosslinking-induced IL-10 in predicting a TNFi therapy response according to the EULAR criteria (AUC = 0.9286, 95% Confidence interval 0.7825-1.000, p = 0.0055). (4) Conclusions: In this pilot investigation, we demonstrated the feasibility of a whole-blood assay measuring tmTNF-induced IL-10 to predict clinical response to TNF inhibitor treatment. This approach might support rheumatologists in their decision for an individually tailored RA therapy.

Herpesvirus entry mediator-Ig treatment during immunization aggravates rheumatoid arthritis in the collagen-induced arthritis model.

Previous studies attempting to influence the severity of collagen-induced arthritis (CIA) by modulating the LIGHT (lymphotoxin-related inducible ligand that competes for glycoprotein D binding to herpesvirus entry mediator (HVEM) on T cells)/lymphotoxin pathway have yielded conflicting results. To further clarify the role of LIGHT in autoimmune arthritis, a HVEM-Ig fusion protein was used. CIA was induced in DBA1 mice, which were injected i.p. with recombinant HVEM-Ig fusion protein and control Ig at different time points. Severity of clinical arthritis and histologic joint destruction were significantly increased in HVEM-Ig-treated mice compared with control-Ig-treated mice. Collagen II-induced in vitro T cell proliferation and IFN-gamma production was augmented in mice treated with HVEM-Ig, as was the production of IgG2a anti-collagen II Ab. Accordingly, serum concentrations of IFN-gamma and IL-6 were higher in mice treated with HVEM-Ig. In conclusion, HVEM-Ig aggravates autoimmunity in collagen-induced arthritis, which is possibly mediated by interaction with B and T lymphocyte attenuator (BTLA) or CD160, despite the blockade of LIGHT. Hence, HVEM-Ig seems not to be a valid therapeutic option in autoimmune arthritis.

Clonal expansions in selected TCR BV families of rheumatoid arthritis patients are reduced by treatment with the TNFα inhibitors etanercept and infliximab.

Clonal expansions of autoreactive CD4+ T cells are frequently present in patients with rheumatoid arthritis (RA) and are stable over long periods of time. This study was undertaken to investigate the influence of anti-TNFα treatment on such clonal expansions in the peripheral CD4+ T-cell compartment. TNFα inhibiting therapies significantly reduced the total number of expanded clonotypes. This effect was mainly observed in clonal expansions in the BV6 family, while in clonal expansions of the BV14 family no such effect was seen. No change in the percentage of CD4+ CD28 null T cells was observed. Serum concentrations of the pro-homeostatic cytokine IL-7 were found to increase in patients responding TNFα-inhibiting therapy. These data argue for a normalization of adaptive immune mechanisms under TNFα inhibiting therapies, which may be secondary to the control of inflammation but contribute to the efficacy of cytokine blockade therapy.

Vital Hepatic Lymphoma Residuum or Excessive Immune Response? Challenging Treatment Decisions in a Patient With Systemic Lupus Erythematosus and Liver-Dominant Diffuse Large B-Cell Lymphoma: Case Report.

A 28-year-old female patient with active and difficult-to-treat systemic lupus erythematosus (SLE) was diagnosed with liver-dominant diffused large B-cell lymphoma. Repeated response 18F-FDG-PET studies showed persistently high, and, despite intensified immunochemotherapy, further increasing metabolic activity of one of the hepatic lymphoma residuals, whereas all other initial lymphoma manifestations had achieved complete metabolic remission. As biopsy of the 18F-FDG-PET-positive liver residual turned out to be inconclusive, complete resection was performed. Subsequent histopathological examination, however, revealed only necrotic tissue. Thus, no further lymphoma treatment was scheduled. The patient undergoes regular surveillance and is disease-free 13 months after resection. Similarly, treatment of SLE is no longer required due to lack of activity already after the first two cycles of lymphoma treatment. The case shows how closely SLE and diffused large B-cell lymphoma can be connected and stresses the importance of interdisciplinary treatment approaches. In the future, artificial intelligence may help to further classify 18F-FDG-PET-positive lymphoma residuals. This could lead to an increase of the positive predictive value of interim- and end-of-treatment 18F-FDG-PET. The patient's point of view enables another instructive perspective on the course of treatment, which often remains hidden to treating physicians due to lack of time in clinical routine.

Calcium-sensing receptor-mediated NLRP3 inflammasome response to calciprotein particles drives inflammation in rheumatoid arthritis.

Increased extracellular Ca2+ concentrations ([Ca2+]ex) trigger activation of the NLRP3 inflammasome in monocytes through calcium-sensing receptor (CaSR). To prevent extraosseous calcification in vivo, the serum protein fetuin-A stabilizes calcium and phosphate into 70-100 nm-sized colloidal calciprotein particles (CPPs). Here we show that monocytes engulf CPPs via macropinocytosis, and this process is strictly dependent on CaSR signaling triggered by increases in [Ca2+]ex. Enhanced macropinocytosis of CPPs results in increased lysosomal activity, NLRP3 inflammasome activation, and IL-1ß release. Monocytes in the context of rheumatoid arthritis (RA) exhibit increased CPP uptake and IL-1ß release in response to CaSR signaling. CaSR expression in these monocytes and local [Ca2+] in afflicted joints are increased, probably contributing to this enhanced response. We propose that CaSR-mediated NLRP3 inflammasome activation contributes to inflammatory arthritis and systemic inflammation not only in RA, but possibly also in other inflammatory conditions. Inhibition of CaSR-mediated CPP uptake might be a therapeutic approach to treating RA.

[Clinical Course of an Early Childhood-Onset Granulomatosis with Polyangiitis]. / Klinischer Verlauf einer Granulomatose mit Polyangiitis mit frühem Beginn in der Kindheit.

History A 26-year-old male patient presented with an eight-week history of unspecific symptoms such as weight loss and fever. Besides, he also suffered from haemoptysis, cough, and arthralgia. Since the age of twelve years, the patient has been treated for Wegner's granulomatosis. At the age of 20 years he received a kidney transplant which failed only four years later. Investigations The relapse we clinically suspected was confirmed by CT scan showing bilateral pulmonary manifestations. Moreover, we found highly positive antibodies against proteinase 3. Treatment and course After an induction therapy using Glucocorticoids and Rituximab, accompanied by plasmapheresis, the patient's clinical condition showed a marked improvement. We were able to discharge him continuing the treatment in an outpatient setting. Conclusion Childhood-onset GPA is a life-threatening disease and often characterized by recurring relapses as well as a significantly reduced quality of life for the patient.

Colchicine triggered severe rhabdomyolysis after long-term low-dose simvastatin therapy: a case report.

BACKGROUND: Rhabdomyolysis is a widely recognized yet rare complication in statin use. Rhabdomyolysis might be triggered by the prescription of high doses of statins or by statin accumulation due to interactions with concomitant medication. Muscle cell destruction as evidenced by myoglobin elevation can induce potentially life-threatening acute renal failure. CASE PRESENTATION: We report a case of a 70-year-old obese white man with sudden onset of severe rhabdomyolysis with consecutive renal failure. His medication included low-dose simvastatin, which he had taken for 6 years up until the event. The statin was withdrawn immediately. After 3 days of veno-venous hemofiltration his renal function was completely restored. CONCLUSIONS: Clinicians in both primary and special care might be unaware that side effects of statins do occur even after a long uneventful statin medication; they should be advised not to exclude that possibility upfront, even if a patient has tolerated the medication for years.

Latent Cytomegalovirus Infection in Rheumatoid Arthritis and Increased Frequencies of Cytolytic LIR-1+CD8+ T Cells.

OBJECTIVE: Leukocyte immunoglobulin-like receptor 1 (LIR-1) is up-regulated by cytomegalovirus (CMV), which in turn, has been associated with premature aging and more severe joint disease in patients with rheumatoid arthritis (RA). The aim of this study was to investigate the expression and functional significance of LIR-1 in CMV-positive RA patients. METHODS: We determined the phenotype, cytolytic potential, CMV-specific proliferation, and HLA-G-triggered, LIR-1-mediated inhibition of interferon-γ secretion of LIR-1+ T cells in RA patients and healthy controls. RESULTS: We found increased frequencies of CD8+ T cells with CMV pp65-specific T cell receptors in CMV-positive RA patients as compared to CMV-positive healthy controls. CMV-specific CD8+ T cells in these patients were preferentially LIR-1+ and exhibited a terminally differentiated polyfunctional phenotype. The numbers of LIR-1+CD8+ T cells increased with age and disease activity, and showed high levels of reactivity to CMV antigens. Ligation of LIR-1 with soluble HLA-G molecules in vitro confirmed an inhibitory role of the molecule when expressed on CD8+ T cells in RA patients. CONCLUSION: We propose that latent CMV infection in the context of a chronic autoimmune response induces the recently described "chronic infection phenotype" in CD8+ T cells, which retains anti-infectious effector features while exhibiting autoreactive cytolytic potential. This response is likely dampened by LIR-1 to avoid overwhelming immunopathologic changes in the setting of the autoimmune disease RA. The known deficiency of soluble HLA-G in RA and the observed association of LIR-1 expression with disease activity suggest, however, that LIR-1+ T cells are insufficiently controlled in RA and are still likely to be involved in the pathogenesis of the disease.