Objective. To investigate the relationship between endothelium-dependent and endothelium-independent functions and the stiffness of conduit arteries as well as levels of endothelial activation markers in patients with systemic sclerosis (SSc).Methods. Endothelium-dependent (i.e., flowmediated) and endothelium-independent (i.e., nitroglycerin-induced) dilation of the brachial artery was measured as the percentage of change from baseline (FMD% and NTG%, respectively) in 24 SSc patients and 24 age-and sex-matched healthy controls by highresolution ultrasound imaging. The maximum increase in systolic pressure per unit of time (dP/dt max ), as a measure of arterial wall stiffness, was assessed in the radial artery by pulse applanation tonometry. Plasma nitrate, the most important metabolite of nitric oxide, and 24-hour urinary excretion of nitrate were measured by gas chromatography mass spectrometry. Soluble E-selectin and soluble vascular cell adhesion molecule 1 (sVCAM-1) were measured by enzyme-linked immunosorbent assay.Results. Brachial artery FMD% and NTG% did not differ between SSc patients and controls. Radial artery dP/dt max was significantly increased in the patients and correlated significantly with elevated levels of plasma nitrate and sVCAM-1. Twenty-four-hour urinary nitrate excretion tended to be elevated. Brachial artery NTG% was significantly inversely correlated with levels of plasma nitrate and soluble endothelial adhesion molecules.Conclusion. The ability of the brachial arteries to dilate in response to hyperemia and nitroglycerin challenge is preserved in SSc. Stiffness of the radial artery is increased, however. Endothelial activation seems to determine the extent of the brachial artery NTG% and the radial artery dP/dt max . The data are compatible with the hypothesis that nitrate tolerance is present in the vascular smooth muscle cells of the brachial artery wall in SSc.

The expression of melanocortin MC(1) receptors on human peripheral lymphocyte subsets was analysed by flow cytometry using rabbit antibodies selective for the human MC(1) receptor and a panel of monoclonal antibodies against lymphocyte differentiation markers. The MC(1) receptor was found to be constitutively expressed on monocytes/macrophages, B-lymphocytes, natural killer (NK) cells and a subset of cytotoxic T-cells. Interestingly T-helper cells appeared to be essentially devoid of MC(1) receptors. The results were confirmed by RT-PCR which indicated strong expression of MC(1) receptor mRNA in CD14(+), CD19(+) and CD56(+) cells. However, only a faint RT-PCR signal was seen in CD3(+) cells, in line with the immuno-staining results that indicated that only part of the CD3(+) cells (i.e. some of the CD8(+) cells) expressed the MC(1) receptor. The MC(1) receptors' constitutive expression on immune cells with antigen-presenting and cytotoxic functions implies important roles for the melanocortic system in the modulation of immune responses.

Levels of the melanocortin receptor (MCR) 1, 2, 3 and 5 subtypes and pro-opiomelanocortin (POMC) protein mRNA were measured by the real-time quantitative reverse transcriptase polymerase chain reaction method in CD4þ monocytes and CD15 þ granulocytes from healthy donors. We found high levels of all of the MC1, 2, 3 and 5R subtype mRNA in Th cells and moderate levels in NK cells, monocytes and granulocytes. POMC peptide mRNA was found in all examined leucocyte subsets, but only low levels were present in granulocytes. Our findings suggest a co-ordinating role for MCR subtypes and their naturally occurring ligands in the co-operation between innate and adaptive immunity. Moreover, our findings are compatible with earlier finding of MCR-mediated tolerance induction in Th cells.

Systemic sclerosis (SSc) is frequently associated with interstitial lung disease (ILD) often leading to lung fibrosis. In this study we investigated whether matrix metalloproteinase 9 (MMP-9) and its natural inhibitor; the tissue inhibitor of matrix metalloproteinase 1 (TIMP-1), would be associated with remodelling in ILD in SSc. Levels of total MMP-9, pro-MMP-9 and TIMP-1 were measured in bronchoalveolar lavage (BAL) fluid from nine SSc patients with ILD, seven SSc patients without ILD and 16 age- and sex-matched healthy controls. Total MMP-9 and pro-MMP-9 levels were significantly elevated in SSc patients with ILD, compared to levels in SSc patients without ILD and healthy controls. In SSc patients with ILD calculated active MMP-9 levels were significantly higher than in SSc patients without ILD and tended to be higher than in healthy controls. TIMP-1 levels were elevated in both patient groups compared to healthy controls. Total-, pro- and active MMP-9 levels as well as pro-MMP-TIMP-1 and active MMP-9/TIMP-1 ratios were inversely associated with total lung capacity. The present study suggests that MMP-9 plays a pathophysiological role in the remodelling in ILD and lung fibrosis associated with SSc, and may represent a new therapeutic target in this condition.

NO synthesis is elevated in SSc patients, and the activated endothelial cell is a likely site of its production.

The development of an autoimmune disease like systemic sclerosis (SSc) is suspected to be driven by an activated T lymphocyte subset, expressing a cytokine profile specific to the disease. To further characterize the type of immune reaction in SSc, we searched for a broad panel of cytokine messenger ribonucleic acids (mRNAs) in T lymphocytes and monocytes/macrophages from paired samples of bronchoalveolar lavage fluid and peripheral blood in 18 patients and 16 age‐ and sex‐matched controls. RNA from CD3+ T lymphocytes and CD14+ monocytes/macrophages was examined by means of the reverse transcriptase polymerase chain reaction. SSc alveolar T lymphocytes expressed a cytokine profile suggestive of a mixed Th1/Th2 reaction, showing an increased frequency of mRNA for interleukin (IL)‐10, IL‐6 and interferon (IFN)γ, while IL‐1β, IFNγ and tumour necrosis factor β were expressed in blood T lymphocytes in a higher percentage of patients with SSc than controls. SSc alveolar T cells expressed IL‐10 mRNA more often than peripheral T cells, a phenomenon not found in controls and which may point at local IL‐10 activation/response in SSc lung. Transforming growth factor β mRNA was present in all alveolar as well as peripheral blood T cell samples in patients and controls. The cytokine mRNA profile in SSc with interstitial lung disease (ILD) was similar to the profile found in SSc without ILD. Our findings point at a mixed Th1/Th2 reaction in SSc and may indicate regulatory T 1 cell activation/response in the lungs of patients with SSc.

Rheumatoid arthritis (RA) is caused by complex interactions between immune cells and sustained by Th1 response cytokines. Resistin [resistance to insulin; (RETN)] is an inflammatory cytokine, first discovered in murine adipocytes. In man, RETN is mainly secreted by monocytes. The distinct role of RETN in the immune reaction is uncertain; however, RETN has pro-inflammatory, pro-fibrotic and possibly tolerogenic properties. The aim was to assess the reaction of RETN gene expression to TNF-α inhibition (I) in pathogenetic immune cell subsets in RA, in the context of Th1, inflammatory and regulatory cytokine gene expressions. Accordingly, we measured RETN, IFN-γ, TNF-β, IL-1β, TNF-α, TGF-β and IL-10 gene expressions in CD14(+) monocytes, CD4(+) T helper (Th) lymphocytes (ly), CD8(+) T cytotoxic (Tc) ly and CD19(+) B ly in active RA before and 3 months after start of TNF-αI. Leucocyte subsets were separated by specific monoclonal antibody-covered beads, RNA extracted and levels of RETN, Th1 response, inflammatory and regulatory cytokine mRNAs measured by quantitative reverse transcription-polymerase chain reaction technique. We found that TNF-αI caused a significant downregulation of RETN gene expression in CD14(+) monocytes and CD4(+) Th ly and was unchanged in CD8(+) Tc ly and CD19(+) B ly. Both in active RA and during TNF-αI, RETN mRNA levels were significantly higher in CD14(+) monocytes than in all other examined cell types. In monocytes, fold change in RETN and TGF-β gene expressions upon TNF-αI correlated significantly. Our findings indicate that RETN has pro-inflammatory as well as proresolving roles in active RA.

It is concluded that SSc is associated with a chronic neutrophilic inflammation in the bronchial mucosal, with signs of suppressed signal transduction, regardless of the presence of interstitial lung disease.