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.

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

B7 costimulatory molecules are present on antigenpresenting cells (APCs) and influence intracellular expression of indoleamine 2,3-dioxygenase (IDO), a molecule with important immunoregulatory functions. We determined the frequency of activated (CD11b+) monocytes expressing B7-1, B7-2, B7-H1, and B7-H2 molecules, and that of CD3+ and CD4+ T cells expressing the corresponding CD28, CTLA-4, PD-1, and ICOS receptors in peripheral blood samples of 20 healthy adults and 9 SSc and 15 pSS patients using flow cytometry. We also examined the intracellular expression of IDO. The expression of CD28 was lower in both SSc and pSS patients. The frequency of CTLA-4 was increased in pSS. The expression of ICOS, a stimulator of T cell activation, was elevated in pSS, but not in SSc, while that of its corresponding costimulatory molecule, B7-H2, was strongly decreased in SSc compared to controls. The frequency of PD-1 expressing T lymphocytes was decreased in both pSS and SSc. The frequency of IDO-expressing APCs, as well as intracellular IDO content in T cells was higher in pSS than in controls. Our investigation identified a number of differences in B7 costimulation between SSc and pSS patients which may play a role in the distinct pathogenesis and clinical features of these autoimmune disorders.

The altered expression and specific inhibition of potassium channels seem to be related to altered calcium influx kinetics in pSS which distinguish pSS either from healthy controls or other systemic autoimmune diseases.

Purpose To examine the density and the distribution of corneal Langerhans cells (LCs) and to compare the results with dry‐eye related parameters and disease activity in ankylosing spondylitis(AS). Methods Twenty four AS patients (mean age: 41.8±9.8 years) with various degree of disease activity and twenty four healthy subjects (mean age: 47.9 ± 16.4 years) were enrolled. Ocular surface disease index (OSDI), lid parallel conjunctival folds (LIPCOF), tear break up time (TBUT), and Schirmer test (ST) were evaluated. In addition, central and peripheral LCs numbers and Langerhans cell morphology (LCM) were assessed with in vivo laser confocal microscopy. Results Tear production was greatly suppressed in patients with more severe systemic inflammation according to the Bath Ankylosing Spondylitis Disease Activity Index (BASDAI) and C‐reactive protein (CRP) (BASDAI≤4.0 vs BASDAI>4.0 10.2±8.5 vs 4.0±5.3; CRP≤5.0 vs CRP>5.0 17.2±4.2 vs 3.9±5.5 p<0.05 for all). LCs densities and central LCM were greater in AS patients than in the controls (LC density: 77.5±44.9 vs 23.8±33.8 and central LCM: 1.7±0.7 vs 0.95±0.75 p<0.05 for all). Conclusion Greater corneal LC density and LCM may reflect an increased activation of the corneal innate immune system, which correlates with the systemic activity of AS even without ocular symptoms. Higher systemic inflammation might impair tear production, and it might partly explain the dry eye mechanism.