Innate and adaptive immunity represent a harmonic counterbalanced system involved in the induction, progression, and possibly resolution of the inflammatory reaction that characterize autoimmune rheumatic diseases (ARDs), including rheumatoid arthritis (RA). Although the immunopathophysiological mechanisms of the ARDs are not fully clarified, they are often associated with an inappropriate macrophage/T-cell interaction, where classical (M1) or alternative (M2) macrophage activation may influence the occurrence of T-helper (Th)1 or Th2 responses. In RA patients, M1/Th1 activation occurs in an inflammatory environment dominated by Toll-like receptor (TLR) and interferon (IFN) signaling, and it promotes a massive production of pro-inflammatory cytokines [i.e., tumor necrosis factor-α (TNFα), interleukin (IL)-1, IL-12, IL-18, and IFNγ], chemotactic factors, and matrix metalloproteinases resulting in osteoclastogenesis, erosion, and progressive joint destruction. On the other hand, the activation of M2/Th2 response determines the release of growth factors and cytokines [i.e., IL-4, IL-10, IL-13, and transforming growth factor (TGF)-β] involved in the anti-inflammatory process leading to the clinical remission of RA. Several subtypes of macrophages have been described. Five polarization states from M1 to M2 have been confirmed in in vitro studies analyzing morphological characteristics, gene expression of phenotype markers (CD80, CD86, TLR2, TLR4, or CD206, CD204, CD163, MerTK), and functional aspect, including the production of reactive oxygen species (ROS). An M1 and M2 macrophage imbalance may induce pathological consequences and contribute to several diseases, such as asthma or osteoclastogenesis in RA patients. In addition, the macrophage dynamic polarization from M1 to M2 includes the presence of intermediate polarity stages distinguished by the expression of specific surface markers and the production/release of distinct molecules (i.e., nitric oxide, cytokines), which characterize their morphological and functional state. This suggests a “continuum” of macrophage activation states playing an important role during inflammation and its resolution. This review discusses the importance of the delicate M1/M2 imbalance in the different phases of the inflammatory process together with the identification of specific pathways, cytokines, and chemokines involved, and its clinical outcomes in RA. The analysis of these aspects could shed a light on the abnormal inflammatory activation, leading to novel therapeutical approaches which may contribute to restore the M1/M2 balance.

Background In rheumatoid arthritis (RA), macrophages play an important role in modulating the immunoinflammatory response through their polarisation into “classically” (M1) or “alternatively activated” (M2) phenotypes. In RA, CTLA4-Ig (abatacept) reduces the inflammatory activity of macrophages by interacting with the costimulatory molecule CD86. The study aimed to investigate the efficacy of CTLA4-Ig treatment to induce an M2 phenotype both in M1-polarised monocyte-derived macrophages (MDMs) obtained from healthy subjects (HS) and in cultured MDMs obtained from active RA patients. Methods Cultured MDMs were obtained from peripheral blood mononuclear cells of 7 active RA patients and from 10 HS after stimulation with phorbol myristate acetate (5 ng/mL) for 24 h. HS-MDMs were then stimulated with lipopolysaccharide (LPS, 1 mg/mL) for 4 h to induce M1-MDMs. M1-MDMs and RA-MDMs were treated with CTLA4-Ig (100 μM and 500 μM) for 3, 12, 24, and 48 h. The gene expression of CD80, CD86, and TLR4 (M1 markers); CD163, CD204, and CD206 (surface M2 markers); and MerTK (functional M2 marker) was evaluated by qRT-PCR. The protein synthesis of surface M2 markers was investigated by Western blotting. The statistical analysis was performed by the Wilcoxon t-test. Results In LPS-induced HS-M1-MDMs, CTLA4-Ig 100 μM and 500 μM significantly downregulated the gene expression of M1 markers (3 h p<0.01 for all molecules; 12 h p<0.05 for TLR4 and CD86) and significantly upregulated that of M2 markers, primarily after 12 h of treatment (CD163: p < 0.01 and p < 0.05; CD206: p < 0.05 and p < 0.01; CD204: p < 0.05 by 100 mg/mL). Moreover, in these cells, CTLA4-Ig 500 μM increased the protein synthesis of surface M2 markers (p < 0.05). Similarly, in RA-MDMs, the CTLA4-Ig treatment significantly downregulated the gene expression of M1 markers at both concentrations primarily after 12 h (p < 0.05). Furthermore, both concentrations of CTLA4-Ig significantly upregulated the gene expression of CD206 (after 3 h of treatment; p < 0.05), CD163, and MerTK (after 12 h of treatment, p < 0.05), whereas CD204 gene expression was significantly upregulated by the high concentration of CTLA4-Ig (p < 0.05). The protein synthesis of all surface markers was increased primarily by CTLA4-Ig 500 μM, significantly for CD204 and CD206 after 24 h of treatment (p < 0.05). Conclusions CTLA4-Ig treatment seems to induce the in vitro shift from M1 to M2 macrophages, of both HS-M1-MDMs and RA-MDMs, as observed by the significant downregulation exerted on selected M1 markers and the upregulation of selected M2 markers suggesting an additional mechanism for its modulation of the RA inflammatory process.

Active vitamin D [1,25(OH)2D3—calcitriol] is a secosteroid hormone whose receptor is expressed on all cells of the immune system. Vitamin D has a global anti-inflammatory effect and its role in the management of a SARS-CoV-2 infection has been investigated since the beginning of the COVID-19 pandemic. In this narrative review, the laboratory and clinical results of a vitamin D supplementation have been collected from both open-label and blinded randomized clinical trials. The results are generally in favor of the utility of maintaining the serum concentrations of calcifediol [25(OH)D3] at around 40 ng/mL and of the absolute usefulness of its supplementation in subjects with deficient serum levels. However, two very recent large-scale studies (one open-label, one placebo-controlled) have called into question the contribution of vitamin D to clinical practice in the era of COVID-19 vaccinations. The precise role of a vitamin D supplementation in the anti-COVID-19 armamentarium requires further investigations in light of the breakthrough which has been achieved with mass vaccinations.

Background: Specific autoantibodies and nailfold videocapillaroscopy (NVC) findings are serum and morphological diagnostic hallmarks of systemic sclerosis (SSc) as well as useful biomarkers which stratify the microvascular progression and prognosis of patients. Methods: The aim of our narrative review is to provide an update and overview of the link between SSc-related autoantibodies, used in clinical practice, and microvascular damage, evaluated by NVC, by exploring the interaction between these players in published studies. A narrative review was conducted by searching relevant keywords related to this field in Pubmed, Medline and EULAR/ACR conference abstracts with a focus on the findings published in the last 5 years. Results: Our search yielded 13 clinical studies and 10 pre-clinical studies. Most of the clinical studies (8/13, 61.5%) reported a significant association between SSc-related autoantibodies and NVC patterns: more specifically anti-centromere autoantibodies (ACA) were associated more often with an “Early” NVC pattern, whereas anti-topoisomerase autoantibodies (ATA) more frequently showed an “Active” or “Late” NVC pattern. Five studies, instead, did not find a significant association between specific autoantibodies and NVC findings. Among the pre-clinical studies, SSc-related autoantibodies showed different mechanisms of damage towards both endothelial cells, fibroblasts and smooth muscle vascular cells. Conclusions: The clinical and laboratory evidence on SSc-related autoantibodies and microvascular damage shows that these players are interconnected. Further clinical and demographic factors (e.g., age, sex, disease duration, treatment and comorbidities) might play an additional role in the SSc-related microvascular injury whose progression appears to be complex and multifactorial.

BackgroundRheumatoid arthritis (RA) is a chronic inflammatory autoimmune disease characterized by arthritis and a range of extra-articular organ involvement. Altered microcirculation is an important contributor to the inflammatory reaction characterizing RA and is involved in synovitis and systemic organ manifestations[1]. Nailfold video capillaroscopy (NVC) is a reliable, safe and highly sensitive method for evaluating the morphology of microcirculation and detailed alterations[2].ObjectivesThe objective of the study was to evaluate the microcirculation in adult RA patients by using NVC and to identify morphological and quantifiable NVC parameters with possible correlations with clinical and laboratory findings.MethodsNVC was performed at baseline on 8 fingers of both hands of 25 RA patients (EULAR/ACR 2010 criteria) (mean age 68.57±13.47 years, mean disease duration 14.6±8.6 years)[3]. Different NVC parameters indicating microvascular damage were detected and analyzed, such as microvascular architecture, capillary morphology and loss of capillaries (linear/mm). The results were categorized into “non-scleroderma” pattern, such as “normal” and “non-specific alterations”, as well as “scleroderma” and “scleroderma-like” pattern. The RA patients were treated (at the time of the analysis) with low dose glucocorticoids, NSAIDs and cDMARDs (see Table 1). Statistical analysis was performed by nonparametric tests.ResultsThe patient’s mean age at the time of NVC was 62.68±12.68 years and they consisted mostly of women (84%). The caucasian cohort was composed of 56% seropositive RA patients, all of which were RF positive (100%) and 71.43% also presented anti-CCP positivity. Nine patients (36%) were affected by Raynaud phenomenon.Eighty-four percent of RA patients (84%) presented together with normal capillaries a varying degree of microvascular nonspecific findings, like tortuosity, capillary crossing as well as some abnormal shapes (ramified capillaries).Interestingly, “Early” scleroderma NVC pattern was observed in 1 patient (4%), showing giant capillaries and microhaemorrhages. “Scleroderma-like” capillaroscopic pattern was found in 2 patients (8%) with the following features: dilatations, giant capillaries, microhaemorrhages, abnormal capillary shape with ramifications and reduced mean capillary number per linear mm. NVC observation of “Early” scleroderma pattern and “Scleroderma-like” pattern in 3 patients (12%), suggested the coexistence of an overlap syndrome (most likely MCTD), also supported by clinical and autoantibodies specificities. No specific RA NVC pattern was detectable.No statistically significant correlations were found between different NVC parameters and autoantibodies or specific RA clinical features.ConclusionThe results of present study confirm in sample size that a specific NVC pattern is not detectable in RA, even in early RA patients. The presence of specific patterns, like “Early” scleroderma NCV pattern and “scleroderma-like” pattern, suggest in those “RA patients” the presence of an overlap syndrome. The inclusion of the NVC analysis in patients affected by autoimmune connective tissue diseases (like RA) may contribute to a better definition of the diagnosis, especially in presence of complex clinical symptomatology (overlap syndromes).References[1] Angeloudi E et al. Mediterr J Rheumatol. 2022.[2] Cutolo M et al. Nat Rev Rheumatol. 2021.[3] Aletaha D et al. Arthritis Rheum. 2010.Table 1.Demographic and clinical characteristics of RA patientsn. 25female/male21/4 (5.25:1)current age (years, mean±SD)68.56 (13.47)age at diagnosis (years, mean±SD)53.96 (14.48)seropositive RA14 (56%)FR+14/14 (100%)ACPA+10/14 (71.43%)ANA+7 (28%)ENA+2 (8%)Raynaud phenomenon9 (12%)NVC performed at diagnosis5 (20%)Therapy at NVC baselineNSAIDs2 (8%)glucocorticoids19 (76%)cDMARDs19 (76%)NSAIDs: non-steroidal anti-inflammatory drugs;cDMARDs: conventional disease-modifying antirheumatic drugs.Acknowledgements:NIL.Disclosure of InterestsNone Declared.