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© Copyright Clinical and Experimental Rheumatology 2022., Objectives: To define the clinical spectrum time-course and prognosis of non-Asian patients positive for anti-MDA5 antibodies. Methods: We conducted a multicentre, international, retrospective cohort study. Results: 149 anti-MDA5 positive patients (median onset age 53 years, median disease duration 18 months), mainly females (100, 67%), were included. Dermatomyositis (64, 43%) and amyopathic dermatomyositis (47, 31%), were the main diagnosis; 15 patients (10%) were classified as interstitial pneumonia with autoimmune features (IPAF) and 7 (5%) as rheumatoid arthritis. The main clinical findings observed were myositis (84, 56%), interstitial lung disease (ILD) (108, 78%), skin lesions (111, 74%), and arthritis (76, 51%). The onset of these manifestations was not concomitant in 74 cases (50%). Of note, 32 (21.5%) patients were admitted to the intensive care unit for rapidly progressive-ILD, which occurred in median 2 months from lung involvement detection, in the majority of cases (28, 19%) despite previous immunosuppressive treatment. One-third of patients (47, 32% each) was ANA and anti-ENA antibodies negative and a similar percentage was anti-Ro52 kDa antibodies positive. Non-specific interstitial pneumonia (65, 60%), organising pneumonia (23, 21%), and usual interstitial pneumonia-like pattern (14, 13%) were the main ILD patterns observed. Twenty-six patients died (17%), 19 (13%) had a rapidly progressive-ILD. Conclusions: The clinical spectrum of the anti-MDA5 antibodies-related disease is heterogeneous. Rapidly-progressive ILD deeply impacts the prognosis also in non-Asian patients, occurring early during the disease course. Anti-MDA5 antibody positivity should be considered even when baseline autoimmune screening is negative, anti-Ro52 kDa antibodies are positive, and radiology findings show a NSIP pattern.

Objective To examine the expression and regulation of interleukin-21 (IL-21) and IL-21 receptor (IL-21R) in patients with systemic sclerosis (SSc; scleroderma). Methods Skin biopsy specimens were obtained from 23 patients with SSc and 15 healthy controls. IL-21/IL-21R messenger RNA (mRNA) was quantified using real-time polymerase chain reaction (PCR). The expression pattern of IL-21/IL-21R was analyzed by in situ hybridization and Western blotting. Stimulation experiments were performed with cultured dermal fibroblasts from patients with SSc and healthy controls as well as with keratinocytes, using IL-1β, platelet-derived growth factor BB, monocyte chemoattractant protein 1, transforming growth factor β, and IL-21. The SCID-hu skin mouse model was used for in vivo experiments. Results IL-21R mRNA was detected in all biopsy specimens from patients with SSc and controls, with a 4.7-fold increase observed in SSc samples. In situ hybridization and immunohistochemical analysis showed an up-regulation of IL-21R in samples of epidermis from SSc patients, whereas no signal was detected in skin specimens from healthy controls. These results were confirmed in vitro, in that cultured keratinocytes expressed significant levels of IL-21R, whereas no signal was observed in fibroblasts. Interestingly, mRNA for IL-21 could not be detected by real-time PCR and in situ hybridization. Various concentrations of key cytokines in the pathogenesis of SSc did not stimulate the expression of IL-21R mRNA in cultured keratinocytes and dermal fibroblasts. In the SCID mouse transplantation model, the overexpression of IL-21R mRNA in SSc keratinocytes remained unchanged after transplantation. Conclusion The up-regulation of IL-21R in keratinocytes indicates that, similar to fibroblasts and endothelial cells, the expression pattern is altered in SSc. Moreover, the expression of IL-21R appears to be independent of key cytokines that are operant in SSc.

Systemic lupus erythematosus (SLE) is characterized by the production of autoantibodies directed against several nuclear components, such as DNA and histones. Apoptosis was induced in activated human lymphoblasts (n= 6) by UV-B irradiation for 30 sec followed by continuous culturing. An extranuclear accumulation of the nucleosomal histones H2A, H2B, H3, and H4 in cell lysates was observed very early in the process of apoptosis, even before phosphatidylserine externalization occurred on the outer membrane surface of apoptotically dying lymphoblasts. We hypothesize that a dysregulation of apoptosis during these early phases may contribute to the induction of autoimmunity against nuclear autoantigens as seen in SLE.

We recently reported that cross-linking the leukocyte common antigen (CD45) can rapidly induce aggregation of human peripheral blood mononuclear cells via lymphocyte function-associated antigen-1 (LFA-1) and intercellular adhesion molecule-1 (ICAM-1) interactions. Herein, we have examined both T-cell--monocyte cellular interactions and the molecular signaling that are involved in this phenomenon. Experiments using highly purified T lymphocytes showed that CD45-induced aggregation requires the presence of both T cells and monocytes. Cross- linking CD45 only on T lymphocytes, but not on monocytes, initiated cellular clustering after reconstituting to the respective untreated cell type. By several criteria, CD45-induced clustering of T cells to autologous monocytes was shown to be Fc-receptor--independent. When comparing intracellular signaling in leukocyte aggregation induced by CD45 cross-linking versus phorbol myristate-12–13-acetate (PMA) treatment, the former was found to be fivefold to 10-fold more sensitive to H-8, a reagent that effectively blocks cAMP- and cGMP- dependent protein kinases. On the other hand, reagents that increase intracellular cAMP levels (eg, dbcAMP, forskolin, and IBMX), protein kinase C (PKC) inhibitors (eg, staurosporine), and tyrosine kinase inhibitors (eg, herbimycin A and genistein) all readily inhibited PMA- induced, but not CD45 monoclonal antibody-induced, aggregation. We conclude that cross-linking the leukocyte common antigen on T cells induces LFA-1--/ICAM-1--dependent T-cell--monocyte aggregation through a unique signaling pathway independent of PKC, which involves instead cAMP-/cGMP-dependent protein kinases.

The pathogenesis of systemic sclerosis (SSc) is characterized by activation of the immune system, impaired angiogenesis, and activated dermal fibroblasts. The effects of the immunosuppressive agent bucillamine (SA 96) on fibroblasts and angiogenic factors have not been examined. SA 96, and particularly its metabolite SA 981, increased the levels of vascular endothelial growth factor (VEGF) mRNA and protein dose-dependently in dermal fibroblasts from patients with SSc and healthy control subjects without influencing cell viability. SSc fibroblast cultures showed consistently a higher inducibility of VEGF than cultures from healthy control subjects. Preincubation with the SP-1 inhibitor mithramycin as well as blockade of nuclear factor (NF)-kappaB signaling with pyrrolidine dithiocarbamate treatment and IkappaB transfection reduced significantly the transcription of VEGF, indicating that both transcription factors contribute to the activation of VEGF by SA 981. Specific binding of NF-kappaB protein to its binding site after treatment with SA 981 was confirmed by electrophoretic mobility shift assay. In contrast, SA 981 did not influence the stability of VEGF mRNA as analyzed with actinomycin D assays. The study provides evidence for a role of NF-kappaB in the transcriptional regulation of the VEGF gene. SA 96 might have positive aspects on the impaired angiogenesis in patients with SSc.

Adalimumab (D2E7), a human monoclonal antibody that binds to and neutralizes TNFa, is being developed by Abbott (formerly Knoll), under license from Cambridge Antibody Technology (CAT), for the potential treatment of inflammatory disorders such as rheumatoid arthritis (RA) and Crohn's disease. It is also being investigated for the potential treatment of coronary heart disease. Phase II studies for Crohn's disease and phase III for RA were ongoing throughout 2001. Limited data are only available for RA. In January 2002, it was reported that phase III trials of adalimumab for RA had been completed, but details have not been published in the primary literature so far. At this time CAT and Abbott expected to file for US approval in the second quarter of 2002 with a launch date anticipated for 2003. Phase III data are expected to be presented at the European League Against Rheumatism meeting in June 2002. In November 2000, Lehman Brothers predicted a US launch in June 2002 with peak US sales of $600 million in 2007 and a launch in non-US markets in 2003 with peak sales in these markets of $300 million in 2008. In December 2000, Merrill Lynch predicted regulatory clearance in the second half of 2003. The probability of adalimumab reaching the market is estimated to be 70%. In December 2000, Merrill Lynch predicted a 2003 launch, with estimated sales of pounds sterling 3.65 million in that year rising to pounds sterling 30.14 million in 2010. In March 2001, ABN AMRO predicted sales of $73 million in 2003 rising to $392 million in 2007.