Calcium Influx Kinetics and the Characteristics of Potassium Channels in Peripheral T Lymphocytes in Systemic Sclerosis

BACKGROUND

Systemic sclerosis (SSc) is a chronic, immune-mediated, connective tissue disease causing microvascular abnormalities and fibrosis. The cytoplasmic calcium influx kinetics in T lymphocytes governs lymphocyte activation in this inflammatory process. The inhibition of Kv1.3 and IKCa1 potassium channels reduces calcium influx.

METHODS

This study aimed to analyze cytoplasmic calcium influx kinetics following activation in Th1, Th2, and CD8 cells in peripheral blood of 12 healthy individuals and 16 patients with systemic sclerosis using flow cytometry. We also evaluated the effect of the specific inhibition of the Kv1.3 and IKCa1 potassium channels.

RESULTS

We observed higher levels of activation in CD8 compared with Th1 cells in SSc. However, the activation of CD8 cells was lower in SSc compared to healthy controls. Moreover, activation of Th1 lymphocytes was slower in SSc than in healthy controls. The inhibition of IKCa1 channels decreased the activation of Th1 cells, while the inhibition of Kv1.3 channels modified the dynamics of activation of Th1 and Th2 lymphocytes in SSc.

CONCLUSION

Th1 and CD8 cells demonstrate specific activation dynamics and sensitivity to potassium channel inhibition in SSc, distinguishing this condition both from healthy controls and other autoimmune diseases.

Increased plasma soluble urokinase plasminogen activator receptor levels in systemic sclerosis: possible association with microvascular abnormalities and extent of fibrosis

Urokinase plasminogen activator receptor (uPAR) is a key component of the fibrinolytic system involved in extracellular matrix remodeling and angiogenesis. Novel animal models supported the key role of uPAR not only in fibrosis but also in systemic sclerosis (SSc)-related microvascular abnormalities. The aim of this study was to investigate plasma soluble uPAR (suPAR) levels in SSc, and their association with organ-specific involvement.

suPAR concentrations were measured by ELISA in SSc patient (n=83) and in healthy controls (n=29). Simultaneously, CRP and ESR were assessed. Detailed clinical data including skin, lung, heart and microvascular characteristics were evaluated at sampling.

suPAR values were higher in SSc patients than in controls. Subgroup analysis showed higher suPAR values in diffuse cutaneous- than in limited cutaneous SSc and correlated with anti-Scl-70+. suPAR levels also associated with pulmonary function test parameters of fibrosis, presence of microvascular lesions (e.g., Raynaud phenomenon, naifold capillaroscopic abnormalities and digital ulcers) and arthritis.

Our data indicate that suPAR might be a valuable early diagnostic marker of SSc which also correlates with disease severity.

Corneal Langerhans cell and dry eye examinations in ankylosing spondylitis

APCs of the ocular surface, including corneal Langerhans cells (LCs), offer the opportunity to gain insight into the activity of innate immunity. We examined corneal LCs and dry eye parameters in ankylosing spondylitis (AS). Twenty-four AS patients with varying degrees of disease activity and 24 healthy participants were enrolled. Central and peripheral LC numbers, and Langerhans cell morphology (LCM) were assessed with in vivo laser confocal microscopy. In addition, ocular surface disease index, lid parallel conjunctival folds, tear break up time, and Schirmer test were evaluated. LC densities and central LCM were greater in AS patients than in the controls. Moreover, LCM was significantly greater in patients with higher systemic inflammation according to elevated C-reactive protein (CRP). Also, tear production was greatly suppressed in patients with more severe onset of the systemic inflammation according to the Bath Ankylosing Spondylitis Disease Activity Index and elevated CRP. Greater corneal LC density and LCM in AS may reflect an increased activation state of the innate immune system of the cornea in AS, which correlates with the systemic activity of AS even without ocular symptoms. Nonetheless, higher systemic inflammation might impair tear production, and it might partly explain the dry eye mechanism.