To the current data, there have been 6,955,141 COVID-19-related deaths worldwide, reported to WHO. Toll-like receptors (TLRs) implicated in bacterial and virus sensing could be a crosstalk between activation of persistent innate-immune inflammation, and macrophage’s sub-population alterations, implicated in cytokine storm, macrophage over-activation syndrome, unresolved Acute Respiratory Disease Syndrome (ARDS), and death. The aim of this study is to demonstrate the association between Toll-like-receptor-4 (TLR-4)-induced inflammation and macrophage imbalance in the lung inflammatory infiltrate of lethal COVID-19 disease. Twenty-five cases of autopsy lung tissues were studied by digital pathology-based immunohistochemistry to evaluate expression levels of TLR-4 (CD 284), pan-macrophage marker CD68 (clone KP1), sub-population marker related to alveolar macrophage Galectin-3 (GAL-3) (clone 9C4), and myeloid derived CD163 (clone MRQ-26), respectively. SARS-CoV-2 viral persistence has been evaluated by in situ hybridation (ISH) method. This study showed TLR-4 up-regulation in a subgroup of patients, increased macrophage infiltration in both Spike-1⁽⁺⁾ and Spike-1⁽⁻⁾ lungs (p < 0.0001), and a macrophage shift with important down-regulation of GAL-3⁽⁺⁾ alveolar macrophages associated with Spike-1 persistence (p < 0.05), in favor of CD163⁽⁺⁾ myeloid derived monocyte-macrophages. Data show that TLR-4 expression induces a persistent activation of the inflammation, with inefficient resolution, and pathological macrophage shift, thus explaining one of the mechanisms of lethal COVID-19.

Background/Objectives: Even today, interstitial lung disease (ILD) is diagnosed by chest high-resolution computed tomography (lung HR-CT). Large amounts of data are available about the usefulness of transthoracic lung ultrasound (LUS) in ILD. This study aimed to evaluate the transthoracic LUS capacity to discriminate different ILD patterns in systemic sclerosis (SSc) patients, such as usual interstitial pneumonia (UIP), non-specific interstitial pneumonia (NSIP) with ground glass opacification/opacity (GGO), and NSIP with GGO and reticulations, as well as the possibility of identifying progressive fibrosing ILD. Methods: We enrolled SSc-patients attending the outpatient Clinic of the Rheumatology Unit of Policlinico of Foggia and the Rheumatology Unit of Policlinico of Bari who satisfied these inclusion criteria: age older than 18 years; the satisfaction of ACR/EULAR 2013 classification criteria for SSc; chest HR-CT scan within three months before or three months after transthoracic LUS evaluation; and availability of recent and complete pulmonary function test. The exclusion criteria were as follows: history or recent reactivation of chronic obstructive pulmonary disease, lung cancer, lung infection, heart failure, pulmonary oedema, pulmonary arterial hypertension, acute respiratory distress syndrome and diffuse alveolar haemorrhage and thoracic surgery. All enrolled SSc-patients underwent transthoracic LUS, performed by an experienced sonographer. The ILD diagnosis and the respective patterns were assessed by chest HR-CT, which still represents the best diagnostic tool. Results: ILD was observed in 99 (63.5%) patients. Of these, 25% had the UIP pattern and 75% the NSIP pattern (46 with GGO, 28 with GGO and reticulations). By receiver operating characteristic (ROC) curve analysis, higher values of accuracy, sensitivity, specificity, and negative clinical utility index (CUI) were found for pleural line irregularity (0.84 (95% CI: 0.75–0.91), 96%, and 73.6%, p = 0.0001; 0.72), and pleural line thickness (0.84 (95% CI: 0.74–0.91), 72%, and 96.4%, p = 0.0001; 0.85) for detecting the UIP pattern. The best performance among transthoracic LUS signs for NSIP with the GGO pattern was observed for B-lines (accuracy: 0.88 (95% CI: 0.80–0.93), sensitivity: 93.4% and specificity: 82.4, p = 0.0001; CUI+: 0.75, CUI−: 0.77). LUS signs with higher accuracy, sensitivity, and specificity for NSIP with GGO and reticulations were pleural line irregularity (0.89 (95% CI: 0.80–0.95), 96.4%, and 82.4%, p = 0.0001) with CUI−: 0.72, and B-lines (0.89 (95% CI: 0.80–0.95), 96.4%, 82.4%, p = 0.0001), with CUI+: 0.80 and CUI−: 0.70. Furthermore, a total number of B-lines > 10 maximises LUS performance with 92.3% sensitivity, and an accuracy of 0.83 (p = 0.0001) for detecting the NSIP pattern, particularly GGO. A sample-restricted analysis (66 SSc patients) evidenced the presence of progressive fibrosing ILD in 77% of these patients. By binary regression analysis, the unique LUS sign associated with progressive fibrosing ILD was the presence of pleural line irregularity (OR: 3.6; 95% CI 1.08–11.9; p = 0.036). Conclusions: Our study demonstrated that transthoracic LUS presented a high capacity to discriminate the different patterns of SSc-ILD. Therefore, the hypothesis that transthoracic LUS is an effective screening method for the evaluation of the presence of SSc-ILD and establishing the correct timing of chest HR-CT, in order to avoid patients receiving excessive exposure to ionising radiation, is supported.

Patients with COVID-19 have coagulation and platelet disorders, with platelet alterations and thrombocytopenia representing negative prognostic parameters associated with severe forms of the disease and increased lethality. Methods: The aim of this study was to study the expression of platelet glycoprotein IIIa (CD61), playing a critical role in platelet aggregation, together with TRL-2 as a marker of innate immune activation. Results: A total of 25 patients were investigated, with the majority (24/25, 96%) having co-morbidities and dying from a fatal form of SARS-CoV-2(+) infection (COVID-19+), with 13 men and 12 females ranging in age from 45 to 80 years. When compared to a control group of SARS-CoV-2 (−) negative lungs (COVID-19−), TLR-2 expression was up-regulated in a subset of patients with deadly COVID-19 fatal lung illness. The proportion of Spike-1 (+) patients found by PCR and ISH correlates to the proportion of Spike-S1-positive cases as detected by digital pathology examination. Furthermore, CD61 expression was considerably higher in the lungs of deceased patients. In conclusion, we demonstrate that innate immune prolonged hyperactivation is related to platelet/megakaryocyte over-expression in the lung. Conclusions: Microthrombosis in deadly COVID-19+ lung disease is associated with an increase in the number of CD61+ platelets and megakaryocytes in the pulmonary interstitium, as well as their functional activation; this phenomenon is associated with increased expression of innate immunity TLR2+ cells, which binds the SARS-CoV-2 E protein, and significantly with the persistence of the Spike-S1 viral sequence.

Systemic sclerosis is a rare rheumatic disease characterized by immune cell activation, tissue fibrosis, and endothelial dysfunction. Extracellular matrix synthesis disorder causes widespread fibrosis, primarily in skin and internal organs. Various factors such as TGFβ, VEGF, Galectin-3, and signaling pathways like Wnt/β-catenin are involved in pathophysiological processes. Treatment lacks a unified approach but combines diverse modalities tailored to disease subtype and progression. Current therapeutic strategies include biologics, JAK inhibitors, and IL-6 pathway modulators. Monoclonal antibodies and hypomethylating agents demonstrate potential in fibrosis inhibition. This review focuses on emerging therapeutic evidence regarding drugs targeting collagen, cytokines, and cell surface molecules in systemic sclerosis, aiming to provide insight into potential innovative treatment strategies.

Giulio Giancaspro, M.D., Cinzia Rotondo, M.D., Raffaele Barile, M.D., Valeria Rella, M.D., Jlenia Casciaro, M.D., Luigi Nardella, M.D., Francesco Paolo Cantatore, M.D., Addolorata Corrado, M.D.. J Rheum Dis -0001;0:232-. https://doi.org/10.4078/jrd.2025.0136