Wnt signaling regulates chemokine production and cell migration of circulating human monocytes.

The ß-catenin dependent canonical Wnt signaling pathway plays a crucial role in maintaining normal homeostasis. However, when dysregulated, Wnt signaling is closely associated with various pathological conditions, including inflammation and different types of cancer.Here, we show a new connection between the leukocyte inflammatory response and the Wnt signaling pathway. Specifically, we demonstrate that circulating human primary monocytes express distinct Wnt signaling components and are susceptible to stimulation by the classical Wnt ligand-Wnt-3a. Although this stimulation increased the levels of ß-catenin protein, the expression of the classical Wnt-target genes was not affected. Intriguingly, treating circulating human monocytes with Wnt-3a induces the secretion of cytokines and chemokines, enhancing monocyte migration. Mechanistically, the enhanced monocyte migration in response to Wnt stimuli is mediated through CCL2, a strong monocyte-chemoattractant.To further explore the physiological relevance of these findings, we conducted ex-vivo experiments using blood samples of patients with rheumatic joint diseases (RJD) - conditions where monocytes are known to be dysfunctional. Wnt-3a generated a unique cytokine expression profile, which was significantly distinct from that observed in monocytes obtained from healthy donors.Thus, our results provide the first evidence that Wnt-3a may serve as a potent stimulator of monocyte-driven immune processes. These findings contribute to our understanding of inflammatory diseases and, more importantly, shed light on the role of a core signaling pathway in the circulation.

Steroid treatment suppresses the CD4+ T-cell response to the third dose of mRNA COVID-19 vaccine in systemic autoimmune rheumatic disease patients.

Prolonged steroid treatment has a suppressive effect on the immune system, however, its effect on the cellular response to mRNA vaccine is unknown. Here we assessed the impact of prolonged steroid treatment on the T-cell and humoral response to the SARS-CoV-2 spike (S) peptide following the third dose of the BNT162b2 vaccine in systemic autoimmune rheumatic disease patients. We found that CD4 T-cell response to the S peptide in patients on high-dose long-term steroid treatment showed significantly less S-peptide specific response, compare to low-dose or untreated patients. Remarkably, these results were not reflected in their humoral response, since almost all patients in the cohort had sufficient antibody levels. Moreover, S-peptide activation failed to induce significant mRNA levels of IFNγ and TNFα in patients receiving high-dose steroids. RNA-sequencing datasets analysis implies that steroid treatments' inhibitory effect of nuclear factor kappa-B signaling may interfere with the activation of S-specific CD4 T-cells. This reveals that high-dose steroid treatment inhibits T-cell response to the mRNA vaccine, despite having sufficient antibody levels. Since T-cell immunity is a crucial factor in the immune response to viruses, our findings highlight the need for enhancing the efficiency of vaccines in immune-suppressive patients, by modulation of the T-cell response.

Immunogenicity and safety of the mRNA-based BNT162b2 vaccine in systemic autoimmune rheumatic diseases patients.

BACKGROUND: The COVID-19 outbreak has led to the rapid development and administration of the COVID-19 vaccines worldwide. Data about the immunogenicity and adverse effects of the vaccine on patients with systemic autoimmune rheumatic diseases (SARDs) is emerging. AIM: To evaluate Pfizer/BioNTech (BNT162b2) mRNA-based vaccine second-dose immunogenicity and safety, and the relation between them, in patients with SARDs. METHODS: A total of one hundred forty tow adults who received two doses of the BNT162b2 vaccine were included in the study. The SARDs group included Ninety-nine patients and the control group (forty-three participants) comprised a mixture of healthy participants and patients who were seen at the rheumatology clinic for non-SARDs. Anti-SARS-CoV-2 IgG antibodies against the Spike protein were evaluated using a SARS-CoV-2 IgG immunoassay. A level of > 150 AU/mL was considered positive. An adverse effects questionnaire was given to the participants upon their first visit to the clinic after their BNT162b2 vaccination. RESULTS: Of the 142 participants, 116 were seropositive (81.7%) and 26 (18.3%) were seronegative. Of the seronegative participants, 96.2% were SARDs patients. The proportion of seropositivity in the SARDs patients treated with any immunosuppressant was significantly lower (69.9%) compared to the control group and SARDs patients not receiving immunosuppressants (96.8%). A significant negative correlation between seronegativity and treatment with rituximab, mycophenolate mofetil (MMF), and prednisone was found in the SARDs group (p = 0.004, 0.044, 0.007 respectively). No fever was observed following the BNT162b2 vaccine in seronegative patients, and the frequency of musculoskeletal adverse effects upon the second dose of the BNT162b2 vaccine was significantly higher in seropositive compared to seronegative patients and in the control group compared to the SARDs patients (p = 0.045, p = 0.02 respectively). CONCLUSION: A decline in the immunogenicity to the second dose of BNT162b2 mRNA is seen in patients with SARDs, especially in patients treated with rituximab, MMF, and prednisone. Adverse effects of the vaccine including fever and musculoskeletal symptoms might be a signal for the acquisition of immunity in those patients. KEY POINTS: • BNT162b2 mRNA vaccine is less immunogenic in SARDs patients compared to the control group. • Rituximab, prednisone, and mycophenolate mofetil significantly reduced immunogenicity to the vaccine. • There is a correlation between immunogenicity and adverse effects of the vaccine.

Elevated plasma level of soluble triggering receptor expressed on myeloid cells-1 is associated with inflammation activity and is a potential biomarker of thrombosis in primary antiphospholipid syndrome.

BACKGROUND: Soluble triggering receptor expressed on myeloid cells-1 (sTREM-1) is an innate-immune receptor found in blood. Its presence reflects innate immune cell activation. We sought to investigate plasma sTREM-1 levels in patients with primary antiphospholipid syndrome (PAPS). METHODS: A cross-sectional, case-control design was used. Plasma sTREM-1 levels were analyzed by enzyme-linked immunosorbent assay (ELISA) in consecutive patients diagnosed with PAPS or asymptomatic antiphospholipid antibody (APLA) carriers and controls. RESULTS: The study cohort included 33 patients with PAPS, 10 asymptomatic APLA carriers, and 73 controls. Mean plasma sTREM-1 levels were significantly higher in patients with PAPS (299.2 ± 146.7 pg/ml) and thrombotic PAPS-ever (current and past thrombotic event) (327.2 ± 151.3 pg/ml) compared with controls (230.2 ± 85.5 pg/ml; p = 0.006 and p = 0.003, respectively), patients with thrombotic PAPS compared with patients with past obstetric APS (195.12 ± 58.52 pg/ml, p = 0.01) and APLA carriers (215.8 ± 51.6 pg/ml, p = 0.02), patients with current thrombotic PAPS (429.5 ± 227.5 pg/ml) compared with patients with past thrombotic PAPS (289.5 ± 94.65 pg/ml, p = 0.01), and patients with PAPS who had ever had a stroke or venous thromboembolic event compared with patients who had not (p = 0.007 and p = 0.02, respectively). On receiver operator characteristic curve analysis, plasma sTREM-1 levels differentiated patients with current thrombotic PAPS from asymptomatic APLA carriers and controls, with an area under the curve of 0.7292 (p = 0.0014) and 0.88 (p < 0.0001), respectively. Multivariate regression analysis to identify sTREM-1 predictors (thrombotic PAPS-ever, age, and sex) yielded an independent association of sTREM-1 levels with thrombotic PAPS (p < 0.0001). CONCLUSIONS: Plasma sTREM-1 levels are significantly elevated in patients with thrombotic PAPS. Levels of sTREM-1 might serve as a biomarker for thrombosis in patients with PAPS.