Calprotectin (S100A8/S100A9) detects inflammatory activity in rheumatoid arthritis patients receiving tocilizumab therapy

Serum Calprotectin in the Evaluation of Gastrointestinal Diseases: An Ace up Your Sleeve?

Background: Calprotectin (CP) is a calcium- and zinc-binding protein that plays a key role in innate immunity and in the recruitment of inflammatory cells. CP can be detected both in serum and in fecal samples. Serum CP (sCP) is more specific for autoimmune diseases, while fecal CP (fCP) has been well investigated for gastrointestinal diseases. Few studies have shown the clinical effectiveness of sCP as an acute-phase biomarker for gastrointestinal diseases. Aim: The aim of this narrative review is to discuss the role of sCP as a useful alternative biomarker of the acute-phase activity of gastrointestinal diseases and as a possible tool for screening and monitoring these diseases. Material and Methods: We searched original articles, abstracts, reviews, case reports, and clinical trials on PubMed®, Up-to-Date®, and Medscape® in the last ten years. Conclusion: We found that sCP could represent a useful biomarker in the evaluation of the inflammatory stage in patients with immune-mediated gastrointestinal diseases, but more studies are needed to promote its routine use in clinical practice as a diagnostic and prognostic biomarker as a replacement for fCP.

The Role of Alarmins in the Pathogenesis of Rheumatoid Arthritis, Osteoarthritis, and Psoriasis

Alarmins are immune-activating factors released after cellular injury or death. By secreting alarmins, cells can interact with immune cells and induce a variety of inflammatory responses. The broad family of alarmins involves several members, such as high-mobility group box 1, S100 proteins, interleukin-33, and heat shock proteins, among others. Studies have found that the concentrations and expression profiles of alarmins are altered in immune-mediated diseases. Furthermore, they are involved in the pathogenesis of inflammatory conditions. The aim of this narrative review is to present the current evidence on the role of alarmins in rheumatoid arthritis, osteoarthritis, and psoriasis. We discuss their potential involvement in mechanisms underlying the progression of these diseases and whether they could become therapeutic targets. Moreover, we summarize the impact of pharmacological agents used in the treatment of these diseases on the expression of alarmins.

Comparison of Angio PLanewave UltraSensitive and Power Doppler Ultrasound in Detecting Synovial Blood Flow in Wrist and Finger Joints of Rheumatoid Arthritis Patients

RATIONALE AND OBJECTIVES

The purpose of this study is to conduct a comparison between the newly introduced Angio PLanewave UltraSensitive (AngioPLUS) method and the power Doppler ultrasound (PDUS) technique, evaluating the efficacy of these two methods in detecting synovial blood flow in wrist and finger joints of rheumatoid arthritis (RA) patients. Furthermore, the study aimed to investigate the potential associations between the observed blood flow patterns and various symptoms and indicators associated with RA.

MATERIALS AND METHODS

A cohort of 101 patients diagnosed with RA was included and subsequently categorized into two groups: 20 male participants (19.80%) and 81 female participants (80.20%). Their grayscale ultrasound, PDUS, and AngioPLUS were utilized to acquire data, and subsequent scoring was conducted. Serological tests of the patients were also performed, and DAS28 scores were calculated. The McNemar and Wilcoxon tests were used to compare the blood flow display rate and grading of PDUS as well as AngioPLUS, respectively.

RESULTS

AngioPLUS blood was significantly improved compared to PDUS. In all joints, the proportion of slight and significant improvement in wrist joints was the highest (14.11% and 1.98%, respectively). AngioPLUS was moderately correlated with C-reactive Protein (CRP), Disease Activity Score that includes 28-joint counts, and swollen joint counts and weakly correlated with platelet, hemoglobin, tender joint counts, and CRP before and after treatment.

CONCLUSION

Compared to PDUS, AngioPLUS has a better auxiliary diagnostic role in evaluating disease activity and can provide a reference to improve the management of RA further.

Elevated level of circulating calprotectin correlates with severity and high mortality in patients with COVID-19

BACKGROUND

Patients with coronavirus disease-2019 (COVID-19) are characterized by hyperinflammation. Calprotectin (S100A8/S100A9) is a calcium- and zinc-binding protein mainly secreted by neutrophilic granulocytes or macrophages and has been suggested to be correlated with the severity and prognosis of COVID-19.

AIM

To thoroughly evaluate the diagnostic and prognostic utility of calprotectin in patients with COVID-19 by analyzing relevant studies.

METHODS

PubMed, Web of Science, and Cochrane Library were comprehensively searched from inception to August 1, 2023 to retrieve studies about the application of calprotectin in COVID-19. Useful data such as the level of calprotectin in different groups and the diagnostic efficacy of this biomarker for severe COVID-19 were extracted and aggregated by using Stata 16.0 software.

RESULTS

Fifteen studies were brought into this meta-analysis. First, the pooled standardized mean differences (SMDs) were used to estimate the differences in the levels of circulating calprotectin between patients with severe and non-severe COVID-19. The results showed an overall estimate of 1.84 (95% confidence interval [CI]: 1.09-2.60). Diagnostic information was extracted from 11 studies, and the pooled sensitivity and specificity of calprotectin for diagnosing severe COVID-19 were 0.75 (95% CI: 0.64-0.84) and 0.88 (95% CI: 0.79-0.94), respectively. The AUC was 0.89 and the pooled DOR was 18.44 (95% CI: 9.07-37.51). Furthermore, there was a strong correlation between elevated levels of circulating calprotectin and a higher risk of mortality outcomes in COVID-19 patients (odds ratio: 8.60, 95% CI: 2.17-34.12; p < 0.1).

CONCLUSION

This meta-analysis showed that calprotectin was elevated in patients with severe COVID-19, and this atypical inflammatory cytokine might serve as a useful biomarker to distinguish the severity of COVID-19 and predict the prognosis.

New blood biomarkers and imaging for disease stratification and monitoring of giant cell arteritis

Relapses and late complications remain a concern in giant cell arteritis (GCA). Monitoring strategies are required to effectively tailor treatment and improve patients' outcomes. Current monitoring of GCA is based on clinical assessment and evaluation of traditional inflammatory markers such as C reactive protein and erythrocyte sedimentation rate; however, this approach has limited value in patients receiving interleukin (IL)-6 blocking agents. New blood biomarkers that are less dependent on the IL-6 axis such as IL-23, B cell activating factor, osteopontin and calprotectin have been explored, but none of them has yet accumulated sufficient evidence to qualify as a routine follow-up parameter. Imaging techniques, including ultrasound and 18F-fluorodeoxyglucose positron emission tomography/computed tomography, potentially offer additional insights; however, the choice of the imaging method as well as its interpretation must be investigated further. Future studies are required to investigate the outcome of patients with GCA whose treatment decisions are based on traditional plus novel (laboratory and imaging) biomarkers as compared with those undergoing conventional monitoring strategies.

Calprotectin: two sides of the same coin

Calprotectin (CLP) is a calcium-binding protein produced by neutrophils and monocytes in the course of inflammation. Today, the role of faecal CLP in chronic IBD is well known, but in recent years attention has shifted towards circulating CLP. In fact, this molecule can be measured in different biological fluids: blood, saliva and urine, using different analytic methods that are described in this review. Furthermore, different data confirm the relevant role of serum CLP in autoimmune diseases. In this review we will highlight the correlation between high levels of circulating CLP and specific autoantibodies of major autoimmune pathologies paving the way to the employment of CLP measurement as useful biomarker for monitoring outcome in different pathologies.

Circulating Calprotectin (cCLP) in autoimmune diseases

BACKGROUND AND AIM

Calprotectin (CLP) is a heterodimeric complex formed by two S100 proteins (S100A8/A9), which plays a pivotal role in innate immunity. Due to its intrinsic cytotoxic and proinflammatory properties, CLP controls cell differentiation, proliferation and NETosis and has been associated with a wide range of rheumatic diseases. Our review summarizes the widespread interest in circulating CLP (cCLP) as a biomarker of neutrophil-related inflammation, in autoimmune rheumatic disease (ARD) and non-ARD.

METHODS

A thorough literature review was performed using PubMed and EMBASE databases searching for circulating calprotectin and synonyms S100A8/A9, myeloid-related protein 8/14 (MRP8/MRP14), calgranulin A/B and L1 protein in addition to specific ARDs and autoimmune non-rheumatic diseases. We selected only English-language articles and excluded abstracts without the main text.

RESULTS

High cCLP serum levels are associated with worse structural outcomes in rheumatoid arthritis and to a lesser extent, in spondyloarthritis. In addition, cCLP can predict disease relapse in some autoimmune diseases including systemic lupus erythematosus (SLE), anti-neutrophil cytoplasmic antibodies-associated vasculitis (AAV) and some severe manifestations of connective tissue diseases, such as glomerulonephritis in SLE, AAV, juvenile idiopathic arthritis, adult-onset Still's disease and lung fibrosis in systemic sclerosis. Therefore, cCLP levels enable the identification of patients who need an accurate and tight follow-up. The clinical usefulness of cCLP as an inflammatory marker has been suggested for inflammatory/autoimmune non-rheumatic diseases, and especially for the monitoring of the inflammatory bowel diseases patients. Currently, there are only a few studies that evaluated the cCLP efficacy as a clinical biomarker in inflammatory/autoimmune non-rheumatic diseases with controversial results. Future studies are warranted to better clarify the role of cCLP in relation to the disease severity in myasthenia gravis, multiple sclerosis, chronic inflammatory demyelinating polyneuropathy, Graves' orbitopathy, autoimmune bullous diseases and uveitis.

CONCLUSION

Our literature review supports a relevant role of cCLP as potential prognostic biomarker mirroring local or systemic inflammation, especially in chronic inflammatory rheumatic diseases.

Clinical significance of tocilizumab-related neutropenia in patients with rheumatoid arthritis

OBJECTIVE

To determine the risks and clinical significance of tocilizumab (TCZ)-related neutropenia, in real-world settings, for patients with rheumatoid arthritis (RA).

METHODS

Medical records of RA patients treated with TCZ at a tertiary referral hospital in South Korea were collected. Infectious complications were defined as cases confirmed by clinical diagnosis and treated with antibiotics.

RESULTS

A total of 277 RA patients with TCZ treatment (intravenous: 152 [54.9%], subcutaneous: 125 [45.1%]) were included in our study. During the observational period, 22 (7%) patients experienced grade 3 neutropenia. No patients discontinued TCZ due to neutropenia, while the dosage of conventional synthetic DMARD (csDMARD) was either reduced or discontinued for 8 patients. Patients, who experienced neutropenia while using csDMARD, had a higher risk for grade 3/4 neutropenia during TCZ treatment (hazard ratio [HR]: 3.120, 95% CI: 1.189-8.189, P=0.021). Among infections, pulmonary infections were the most common (10.35 per 100 patient-years). Age over 60 years (HR: 2.133, 95% CI: 1.118-4.071, P=0.022) and the presence of extra-articular manifestations (adjusted HR: 11.096, 95% CI: 5.353-22.999, P<0.001), but not neutropenia (adjusted HR: 1.263, 95% CI: 0.269-5.945, P=0.77), were risk factors for infections during TCZ treatment.

CONCLUSION

Approximately 7% of RA patients treated with TCZ developed grade 3 neutropenia. The previous history of neutropenia during csDMARD was a risk factor for TCZ-related neutropenia. Age and extra-articular manifestations, but not neutropenia, were risk factors for infection during TCZ treatment, suggesting that TCZ treatment can be maintained in the presence of neutropenia unless infection occurs.