SARS-CoV-2 Igg seroprevalence in IBD patients treated with biologics: first vs. second pandemic wave in a prospective study.

OBJECTIVE: In a prospective study, SARS-CoV-2 IgG seroprevalence was assessed during the second pandemic wave (W2) in a cohort of Inflammatory Bowel Disease (IBD) patients using biologics. The secondary aim was to compare, in the same cohort, the frequency of seropositivity and of COVID-19 during the second vs. the first (W1) wave. PATIENTS AND METHODS: From November 2020 to March 2021, SARS-CoV-2 IgG seropositivity and the prevalence of COVID-19 were assessed in a cohort of IBD patients using biologics already studied at W1. INCLUSION CRITERIA: age ≥ 18 years; diagnosis of IBD; follow-up; written consent. EXCLUSION CRITERIA: SARS-CoV-2 vaccination. Risk factors for infection, compatible symptoms, history of infection or COVID-19, nasopharyngeal swab test were recorded. Data were expressed as median [range]. The χ2 test, Student's t-test, logistic regression analysis was used. RESULTS: IBD cohort at W1 and W2 included 85 patients: 45 CD (52.9%), 40 UC (47.1%). When comparing the same 85 patients at W2 vs. W1, a higher SARS-CoV-2 seroprevalence at W2 was at the limit of the statistical significance (9.4% vs. 2.3%; p=0.05). The prevalence of COVID-19 at W2 vs. W1 was 3.5% (3/85) vs. 0% (0/85) (p=0.08). Contacts with COVID-19 patients and symptoms compatible with COVID-19 were more frequent at W2 vs. W1 (18.8 % vs. 0%; p=0.0001; 34.1% vs. 15.3%; p=0.004). At W2, history of contacts and new onset diarrhea were more frequent in seropositive patients [4/8 (50%) vs. 12/77 (15.6%); p=0.01 and 4/8 (50%) vs. 2/77 (2.6%); p=0.0001]. At W2, the risk factors for seropositivity included cough, fever, new onset diarrhea, rhinitis, arthromyalgia, dysgeusia/anosmia at univariate (p<0.05), but not at multivariate analysis. History of contacts was the only risk factor for seropositivity at univariate (p=0.03), but not at multivariate analysis (p=0.1). CONCLUSIONS: During W2, characterized by a high viral spread, IBD and biologics appeared not to increase the prevalence of SARS-CoV-2 infection or COVID-19 disease. New onset diarrhea mimicking IBD relapse may be observed in patients with SARS-CoV-2 infection.

Low prevalence of SARS-CoV-2 infection in inflammatory bowel disease.

OBJECTIVE: Treatments used in Inflammatory Bowel Disease (IBD) have been associated with enhanced risk of viral infections and viral reactivation, however, it remains unclear whether IBD patients have increased risk of Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) infection. The aim of the study was to examine the prevalence of SARS-CoV-2 IgG positivity in IBD patients followed at our referral center. The role of treatments for IBD and risk factors for infection were also evaluated. PATIENTS AND METHODS: In a prospective study, all IBD patients followed at our referral centre between May 27th and July 21st, 2020 and fulfilling the inclusion criteria were tested for SARS-CoV-2 IgG. Specific IgG antibodies were evaluated by a commercial ELISA kit and SARS-CoV-2 nasopharyngeal swab was performed in seropositive patients. RESULTS: Two-hundred and eighteen patients, 128 Crohn's disease (CD) and 90 Ulcerative colitis (UC) [age 44, (19-77) years; ongoing biologics in 115 (52.7%)] were enrolled. No patient had major SARS-CoV-2-related symptoms. SARS-CoV-2 IgG were detected in 3 out of 218 (1.37%) patients with IBD (2 CD and 1 UC), all on biologics (2.6%). In all of the 3 seropositive patients, the nasopharyngeal swab was negative. There was no relationship between SARS-CoV-2 seroprevalence and the demographic/clinical characteristics of IBD patients. In contrast, history of recent travel was more frequent in the SARS-CoV-2 seropositive patients (2/3; 66.6%) than in SARS-CoV-2 seronegative patients [7/215 (3.25%); p<0.0001]. CONCLUSIONS: The prevalence of SARS-CoV-2 IgG seropositivity in IBD patients appears to be comparable to the non-IBD population and not influenced by ongoing treatments. Risk factors for infection common to the general non-IBD population should be considered when managing patients with IBD.

mTOR sustains inflammatory response in celiac disease.

Celiac disease (CD) is an enteropathy triggered by the ingestion of gluten proteins in genetically predisposed individuals and characterized by excessive activation of effector immune cells and enhanced production of inflammatory cytokines. However, factors/mechanisms that amplify the ongoing mucosal inflammation in CD are not fully understood. In this study, we assessed whether mammalian target of Rapamycin (mTOR), a pathway that combines intra- and extra-cellular signals and acts as a central regulator for the metabolism, growth, and function of immune and non-immune cells, sustains CD-associated immune response. Our findings indicate that expression of phosphorylated (p)/active form of mTOR is increased in protein lysates of duodenal biopsy samples taken from patients with active CD (ACD) as compared to normal controls. In ACD, activation of mTOR occurs mainly in the epithelial compartment and associates with enhanced expression of p-4EBP, a downstream target of mTOR complex (mTORC)1, while expression of p-Rictor, a component of mTORC2, is not increased. Stimulation of mucosal explants of inactive CD patients with pepsin-trypsin-digested (PT)-gliadin or IFN-γ/IL-21, two cytokines produced in CD by gluten-specific T cells, increases p-4EBP expression. Consistently, blockade of such cytokines in cultures of ACD mucosal explants reduces p-4EBP. Finally, we show that inhibition of mTORC1 with rapamycin in ACD mucosal explants reduces p-4EBP and production of IL-15, a master cytokine produced by epithelial cells in this disorder. Our data suggest that ACD inflammation is marked by activation of mTORC1 in the epithelial compartment.

Smad7 positively regulates keratinocyte proliferation in psoriasis.

BACKGROUND: Transforming growth factor (TGF)-ß1 exerts inhibitory effects on keratinocyte proliferation. OBJECTIVES: To examine whether Smad7, a known inhibitor of TGF-ß1 signalling, is involved in psoriasis-associated keratinocyte hyperproliferation. METHODS: Smad7 was evaluated in skin sections of patients with psoriasis and healthy controls and in mice with Aldara-induced skin pathology by real-time polymerase chain reaction and immunohistochemistry. To assess whether Smad7 positively regulates in vivo keratinocyte growth, mice treated with Aldara received daily cutaneous administration of Smad7 antisense oligonucleotide (AS). Keratin (K)6 and K16, cell-cycle-associated factors, cell-cycle and cell proliferation were evaluated in HaCaT cells either treated with Smad7 AS or transfected with Smad7 plasmid and in mice given Smad7 AS. RESULTS: Smad7 was highly expressed in keratinocytes of patients with psoriasis and of mice treated with Aldara. In HaCaT cells, Smad7 knockdown inhibited cell growth, reduced K6 and K16 expression and promoted accumulation of cells in the S-phase of the cell cycle. Smad7-deficient keratinocytes exhibited reduced levels of CDC25A protein, a phosphatase that facilitates progression of cells through the S-phase, and hyperphosphorylation of eukaryotic initiation factor 2 (eIF2)α, a negative regulator of CDC25 protein translation. Consistently, Smad7 overexpression in HaCaT cells was followed by induction of K6 and K16 and increased cell proliferation. Topical application of Smad7 AS to Aldara-treated mice reduced epidermal thickness. CONCLUSIONS: Our data show that Smad7 is overexpressed in human and murine psoriasis and suggest a key role of this molecule in the control of keratinocyte proliferation.

Serum regenerating islet-derived 3-alpha is a biomarker of mucosal enteropathies.

BACKGROUND: The clinical presentation of organic and functional intestinal disorders can overlap and clinicians often rely on invasive and time-consuming procedures to make a final diagnosis. Regenerating islet-derived 3-alpha (Reg3α) is detectable in the circulation of patients with intestinal graft-versus host disease and patients with inflammatory bowel disease (IBD). AIM: To determine whether serum Reg3α testing is useful for discriminating mucosal enteropathies from functional intestinal disorders. METHODS: We prospectively included 47 patients with active coeliac disease (ACD), 13 patients with refractory coeliac disease (RCD), seven patients with common variable immunodeficiency (CVID), 72 patients with active Crohn's disease, 22 patients with active ulcerative colitis (UC) and 28 patients with irritable bowel syndrome (IBS)-related diarrhoea. Sera were also taken from 10 CD patients before and after 6-12 months of a gluten-free diet (GFD) and from 14 patients with IBD before and after induction therapy with Infliximab (IFX). Sera of 119 healthy volunteers were used to determine the cut-off value. Reg3α levels were measured by a commercial ELISA kit. RESULTS: Levels of Reg3α exceeded the cut-off value of the assay in 43/47(91%) ACD patients, 13/13(100%) RCD patients, 7/7(100%) CVID patients, 65/72(90%) Crohn's disease patients, 17/22(77%) UC patients and one patient with IBS(4%). Reg3α levels distinguished mucosal enteropathies from IBS with a sensitivity of 90% and a specificity of 96%. Reg3α levels significantly decreased in CD patients following a GFD and in IBD patients after treatment with IFX. CONCLUSION: Reg3α is a serum biomarker of intestinal damage that, combined with clinical data, identifies patients who should undergo invasive tests for diagnosing enteropathies.

Defective expression of SIRT1 contributes to sustain inflammatory pathways in the gut.

In inflammatory bowel disease (IBD), tissue damage is driven by an excessive immune response, poorly controlled by counter-regulatory mechanisms. SIRT1, a class III NAD+-dependent deacetylase, regulates negatively the expression of various proteins involved in the control of immune-inflammatory pathways, such as Stat3, Smad7, and NF-κB. Here we examined the expression, regulation, and function of SIRT1 in IBD. SIRT1 RNA and protein expression was less pronounced in whole biopsies and lamina propria mononuclear cells (LPMCs) of IBD patients in comparison with normal controls. SIRT1 expression was downregulated in control LPMC by tumor necrosis factor (TNF)-α and interleukin (IL)-21, and upregulated in IBD LPMC by neutralizing TNF-α and IL-21antibodies. Consistently, SIRT1 expression was increased in mucosal samples taken from IBD patients successfully treated with Infliximab. Treatment of IBD LPMC with Cay10591, a specific SIRT1 activator, reduced NF-κB activation and inhibited inflammatory cytokine synthesis, whereas Ex527, an inhibitor of SIRT1, increased interferon (IFN)-γ in control LPMC. SIRT1 was also reduced in mice with colitis induced by 2,4,6-trinitrobenzenesulphonic acid or oxazolone. Cay10591 prevented and cured experimental colitis whereas Ex527 exacerbated disease by modulating T cell-derived cytokine response. Data indicate that SIRT1 is downregulated in IBD patients and colitic mice and suggest that SIRT1 activation can help attenuate inflammatory signals in the gut.