Association between HLA-DRB1, HLA-DRQB1 alleles,and CD4<Superscript>+</Superscript>CD28<Superscript>null</Superscript> T cells in a Chinese population with coronary heart disease

CD4⁺CD28^null T cells are present in increased numbers in the peripheral blood of patients with acute coronary syndrome. However, the triggers of expansion of these cells are unclear. Susceptibility to coronary heart disease (CHD) is strongly associated with alleles of human leukocyte antigen (HLA), but it is not equally strong in different human populations. The objective of the study was to investigate association between CD4⁺CD28^null T cells and HLA-DRB1 alleles. The HLA alleles were determined by polymerase chain reaction with sequence-specific primers (PCR-SSP) method, in a group of CHD patients and control subjects from the same area. The number of CD4⁺CD28^null T cells was measured using the flow cytometry technique. The HLA-DRB1*01 (RR = 4.705, P < 0.005) and DRB1*04 (RR = 3.554, P < 0.005) alleles showed the strongest association with CHD in the Chinese population, and increased numbers of CD4⁺CD28^null T cells were found in association with HLA-DRB1*04 (17.1%) and DRB*01 (12.9%), while decreased numbers of CD4⁺CD28^null T cells were present in subjects with DRB1*15 (0.8%). CHD in Chinese population is strongly associated with HLA-DRB1*01 and DRB1*04 haplotypes, and formation of CD4⁺CD28^null T cells was related to HLA-DRB1*01, DRB1*04, and DRB1*15 alleles.     

Between adaptive and innate immunity: TLR4-mediated perforin production by CD28<Superscript>null</Superscript>T-helper cells in ankylosing spondylitis

CD3⁺CD4⁺CD28^null and CD3⁺CD8⁺CD28^null T cells are enriched in patients with immune-mediated diseases compared with healthy controls. This study shows that CD4⁺CD28^null T cells express Toll-like receptors recognizing bacterial lipopolysaccharides in ankylosing spondylitis, psoriatic arthritis and rheumatoid arthritis. In ankylosing spondylitis, TLR4 (23.1 ± 21.9%) and, to a smaller extent, TLR2 (4.1 ± 5.8%) were expressed on CD4⁺CD28^null T cells, whereas expression was negligible on CD4⁺CD28⁺ and CD8⁺ T cells. CD4⁺CD28^null T cells produced perforin upon stimulation with lipopolysaccharide, and this effect was enhanced by autologous serum or recombinant soluble CD14. Perforin production could be prevented with blocking antibodies directed against CD14 or TLR4. Incubation of peripheral blood mononuclear cells with tumour necrosis factor alpha led to an upregulation of TLR4 and TLR2 on CD4⁺CD28^null T cells in vitro, and treatment of patients with antibodies specifically directed against tumour necrosis factor alpha resulted in decreased expression of TLR4 and TLR2 on CD4⁺CD28^null T cells in vivo. We describe here a new pathway for direct activation of cytotoxic CD4⁺ T cells by components of infectious pathogens. This finding supports the hypothesis that CD4⁺CD28^null T cells represent an immunological link between the innate immune system and the adaptive immune system.     

Characteristics of circulating CD31+ cells from patients with coronary artery disease

Recently, we reported the properties of CD31‐expressing cells in healthy individuals. However, the characteristics of CD31‐expressing cells derived from coronary artery disease (CAD) patients remain unknown. This study aimed to investigate the relationship between circulating CD31⁺ cells and CAD as well as their biological characteristics. Analysis with flow cytometry revealed that CD31⁺ cells (C‐CD31) from the peripheral blood (PB) of CAD patients exhibited low levels of T‐cell marker and high levels of macrophage marker compared with the PB‐CD31⁺ cells from healthy individuals (H‐CD31). In addition, the expression levels of multiple pro‐angiogenic and chemokine genes were significantly down‐regulated in C‐CD31. However, inflammatory gene IL‐1α was highly up‐regulated in C‐CD31. Patients with unstable angina (UA) had significantly more CD31⁺ cells in the PB than healthy control group (P < 0.001). Moreover, there were significant correlations between the number of CD31⁺ cells and cardiovascular (CV) disease activity (R = 0.318, P = 0.006) and the number of diseased coronaries (R = 0.312, P = 0.005). For the diagnostic category of UA, the area under curve was 0.803 (P < 0.001). In conclusion, C‐CD31 have impaired angiogenic potential and the number of circulating CD31⁺ cells were correlated with CV risk. These findings may contribute to the understanding of the pathogenesis of CAD.     

The CD4+CD28null and the regulatory CD4+CD25High T-cell phenotypes in patients with ulcerative colitis during active and quiescent disease, and following colectomy

The CD4⁺CD25^High T-cell phenotype has an essential immunoregulatory role, while the CD4⁺CD28^null T-cell reflects immune pathology. We investigated the profiles of the CD4⁺CD25^High and the CD4⁺CD28^null T-cell phenotypes in patients with ulcerative colitis (UC) during active and quiescent phases as well as following colectomy. Fifty-nine UC patients, 34 active (UCa) and 25 quiescent (UCq) together with 19 healthy controls (HC) were included. Ten of 34 UCa patients underwent colectomy due to unremitting UC (UCo). Immunohistochemical phenotypic of the peripheral blood lymphocytes bearing CD4, CD25 or CD28 was done for analyzes by a multiparameter fluorescence activated cell sorting technique. The expression of the CD4⁺CD25^High phenotype was higher in UCq (P < 0.01) or UCo (P < 0.01) group vs UCa group. Further, the expression of the CD4⁺CD28^null phenotype in UCa or UCo group was higher than in the HC group (P < 0.05). However, the expression of the CD4⁺CD28^null phenotype up to 12 months after colectomy was not significantly different from the levels in the same patients during acute phase. Our impression is that a high CD4⁺CD25^High T-cell reflects alleviation of inflammation, while the expression of the CD4⁺CD28^null T-cell phenotype is an etiologic feature in UC patients, and is maintained after removing the affected colon.     

Phenotypic characteristics of aged CD4+ CD28null T lymphocytes are determined by changes in the whole‐genome DNA methylation pattern

Aging is associated with a progressive loss of the CD28 costimulatory molecule in CD4⁺ lymphocytes (CD28^null T cells), which is accompanied by the acquisition of new biological and functional properties that give rise to an impaired immune response. The regulatory mechanisms that govern the appearance and function of this cell subset during aging and in several associated inflammatory disorders remain controversial. Here, we present the whole‐genome DNA methylation and gene expression profiles of CD28^null T cells and its CD28⁺ counterpart. A comparative analysis revealed that 296 genes are differentially methylated between the two cell subsets. A total of 160 genes associated with cytotoxicity (e.g. GRZB, TYROBP, and RUNX3) and cytokine/chemokine signaling (e.g. CX3CR1, CD27, and IL‐1R) are demethylated in CD28^null T cells, while 136 de novo‐methylated genes matched defects in the TCR signaling pathway (e.g. ITK, TXK, CD3G, and LCK). TCR‐landscape analysis confirmed that CD28^null T cells have an oligo/monoclonal expansion over the polyclonal background of CD28⁺ T cells, but feature a Vβ family repertoire specific to each individual. We reported that CD28^null T cells show a preactivation state characterized by a higher level of expression of inflammasome‐related genes that leads to the release of IL‐1β when activated. Overall, our results demonstrate that CD28^null T cells have a unique DNA methylation landscape, which is associated with differences in gene expression, contributing to the functionality of these cells. Understanding these epigenetic regulatory mechanisms could suggest novel therapeutic strategies to prevent the accumulation and activation of these cells during aging.     

Altered chemokine receptor profile on circulating leukocytes in human heart failure

Chemokines and their receptors have been implicated in the pathogenesis of different forms of heart failure (HF). We examined CC-and CXC-chemokine receptor expression in fresh peripheral blood leukocyte populations from 24 end-stage HF patients consisting of coronary artery disease (CAD; n=6) and hypertrophic cardiomyopathy (HCM; n=7) or idiopathic dilated cardiomyopathy (IDCM; n=8) or valvular disease (VD; n=3) and compared the data with 18 healthy controls. Levels of CCR1, 2, 3, 4, 5, and 7, and CXCR1, 2, 3, and 4 were measured by flow cytometry, and the expression profile was assessed as molecules of equivalent soluble fluorochrome units as well as frequency (percentage) of CD3⁺, CD4⁺, and CD8⁺ T cells and monocytes or granulocytes. Frequency of CD3⁺ CXCR4⁺, CD3⁺ CXCR1⁺, and CD3⁺ CXCR3⁺ cells was significantly increased in HF patients, whereas only CCR7 and CXCR4 expression levels were elevated on CD3⁺ cells. Both CD4⁺ CXCR4⁺ and CD8⁺ CXCR4⁺ cell frequencies were significantly increased irrespective of cardiac disease etiology. Elevated CCR7 expression was less pronounced on CD4⁺ than CD8⁺ cells in patients with CAD and IDCM. Expression of CXCR4 on CD8⁺ cells was upregulated substantially, regardless of the cause of disease. CD8⁺ CXCR1⁺ and CD8⁺ CXCR3⁺ but not CD4⁺ CXCR1⁺ or CD4⁺ CXCR3⁺ cells were increased in the HF patients with IDCM and CAD, respectively. Expression of CXCR1 or CXCR3 on both CD4⁺ and CD8⁺ cells did not differ in all the groups. For monocytes, frequency of CD14⁺ CCR1⁺ and CD14⁺ CCR2⁺ cells was significantly decreased in CAD patients, whereas, increase in CD14⁺ CXCR4⁺ cell frequency was accompanied with elevated CXCR4 expression. On granulocytes, CXCR1 and CXCR2 receptors were downregulated in all patients, compared with controls. Our results suggest that the altered expression profile of CC- and CXC-chemokine receptors on circulating leukocyte populations involves enhanced activation of the immune system, perhaps as part of the pathogenic mechanisms in HF. Modulation of the chemokine network could offer interesting novel therapeutic modalities for end-stage HF.     

Changes of frequency and expression level of CD161 in CD8+ T cells and natural killer T cells in peripheral blood of patients with systemic lupus erythematosus

Immunologic abnormalities of natural killer (NK) cells and T cells play a role in the pathogenesis of systemic lupus erythematosus (SLE). CD161 is expressed on most of the NK cells and on some T cells. The quantities of CD161-expressing cells and expression levels of CD161 were analyzed in T cells and NK cells from patients with SLE compared with normal controls. The expression of CD161 on NK cells, NKT cells, CD4⁺ T cells, and CD8⁺ T cells in peripheral blood from patients with inactive SLE and active SLE, and from the normal controls group were determined using flow cytometry. The frequency and expression level of CD161 in the lymphocyte subsets and its relationship with the quantity of regulatory T cells, anti-double stranded DNA antibody, and the titer of antinuclear antibody were evaluated. Both the percentages of the CD161⁺ subpopulation and the mean fluorescence intensities (MFIs) of CD161 in CD8⁺ T cells and NKT cells decreased significantly in SLE patients compared with normal controls (P < .001). The CD161 expression in CD8⁺ T cells and NKT cells also decreased in the anti-dsDNA (+) group (P < .05). The counts of Treg cells were lower in SLE patients and were weakly correlated with the percentage of the CD161 subpopulation (r = 0.229, P = .016) and the MFIs of CD161 expression in CD8⁺ T cells (r = .232, P = .014). The frequencies and levels of CD161 expression on CD8⁺ T cells and NKT cells were reduced in SLE patients, suggesting that an abnormality of these cells was related to the pathogenesis of SLE.     

Transcriptional profiling of CD133(+) cells in coronary artery disease and effects of exercise on gene expression

Background aimsBone marrow (BM)-derived progenitor cells are under investigation for cardiovascular repair but may be altered by disease. Our aim was to identify differences in gene expression in CD133⁺ cells of patients with coronary artery disease (CAD) and healthy controls, and determine whether exercise modifies gene expression.MethodsCD133⁺ cells were flow-sorted from 10 CAD patients and four controls, and total RNA was isolated for microarray-based gene expression profiling. Genes that were found to be differentially regulated in patients were analyzed further to investigate whether exercise had any normalizing effect on CD133⁺ cells in CAD patients following 3 months of an exercise program.ResultsImprovement in effort tolerance and increases in the number of CD133⁺ cells were observed in CAD patients after 3 months of exercise. Gene expression analysis of the CD133⁺ cells identified 82 differentially expressed genes (2-fold cut-off, 25% false-discovery rate and % present calls) in patients compared with controls, of which 59 were found to be up-regulated and 23 down-regulated. These genes were found to be involved in carbohydrate metabolism, cell cycle, cellular development and signaling, and molecular transport. Following completion of the exercise program, gene expression patterns resembled those of controls in seven of 10 patients.ConclusionsAlterations in gene expression of BM-derived CD133⁺ progenitor cells were found in CAD patients, which in part may be normalized by exercise.     

B cells from Patients with Rheumatoid Arthritis Show Conserved CD39-Mediated Regulatory Function and increased CD39 Expression After Positive Response to Therapy

Rheumatoid arthritis (RA) is a chronic inflammatory disease characterized by progressive joint destruction associated with increased pro-inflammatory mediators. In inflammatory microenvironments, exogenous ATP (eATP) is hydrolyzed to adenosine, which exerts immunosuppressive effects, by the consecutive action of the ectonucleotidases CD39 and CD73. Mature B cells constitutively express both ectonucleotidases, converting these cells to potential suppressors. Here, we assessed CD39 and CD73 expression on B cells from treated or untreated patients with RA. Neither the frequency of CD73⁺CD39⁺ and CD73^-CD39⁺ B cell subsets nor the levels of CD73 and CD39 expression on B cells from untreated or treated RA patients showed significant changes in comparison to healthy controls (HC). CpG+IL-2-stimulated B cells from HC or untreated RA patients increased their CD39 expression, and suppressed CD4⁺ and CD8⁺ T cell proliferation and intracellular TNF-production. A CD39 inhibitor significantly restored proliferation and TNF-producing capacity in CD4⁺ T cells, but not in CD8⁺ T cells, from HC and untreated RA patients, indicating that B cells from untreated RA patients conserved CD39-mediated regulatory function. Good responder patients to therapy (R-RA) exhibited an increased CD39 but not CD73 expression on B cells after treatment, while most of the non-responder (NR) patients showed a reduction in ectoenzyme expression. The positive changes of CD39 expression on B cells exhibited a negative correlation with disease activity and rheumatoid factor levels. Our results suggest modulating the ectoenzymes/ADO pathway as a potential therapy target for improving the course of RA.     

T-cell autoreactivity to citrullinated autoantigenic peptides in rheumatoid arthritis patients carrying HLA-DRB1 shared epitope alleles

Introduction

Anti-citrullinated peptide antibodies are found in rheumatoid arthritis (RA) patients with HLA-DRβ chains encoding the shared epitope (SE) sequence. Citrullination increases self-antigen immunogenicity, through increased binding affinity to SE-containing HLA-DR molecules. To characterise T-cell autoreactivity towards citrullinated self-epitopes, we profiled responses of SE⁺ healthy controls and RA patients to citrullinated and unmodified epitopes of four autoantigens.

Methods

We compared T-cell proliferative and cytokine responses to citrullinated and native type II collagen 1,237 to 1,249, vimentin 66 to 78, aggrecan 84 to 103 and fibrinogen 79 to 91 in six SE⁺ healthy controls and in 21 RA patients with varying disease duration. Cytokine-producing cells were stained after incubation with peptide in the presence of Brefeldin-A.

Results

Although proliferative responses were low, IL-6, IL-17 and TNF were secreted by CD4⁺ T cells of SE⁺ RA patients and healthy controls, as well as IFNγ and IL-10 secreted by RA patients, in response to citrullinated peptides. Of the epitopes tested, citrullinated aggrecan was most immunogenic. Patients with early RA were more likely to produce IL-6 in response to no epitope or to citrullinated aggrecan, while patients with longstanding RA were more likely to produce IL-6 to more than one epitope. Cytokine-producing CD4⁺ T cells included the CD45RO⁺ and CD45RO^- and the CD28⁺ and CD28^- subsets in RA patients.

Conclusion

Proinflammatory cytokines were produced by CD4⁺ T cells in SE⁺ individuals in response to citrullinated self-epitopes, of which citrullinated aggrecan was most immunogenic. Our data suggest that the T-cell response to citrullinated self-epitopes matures and diversifies with development of RA.     

Heterogeneity of CD4 and CD8+ memory T cells in localized and generalized Wegener's granulomatosis

Memory T cells display phenotypic heterogeneity. Surface antigens previously regarded as exclusive markers of naive T cells, such as L-selectin (CD62L), can also be detected on some memory T cells. Moreover, a fraction of CD45RO⁺ (positive for the short human isoform of CD45) memory T cells reverts to the CD45RA⁺ (positive for the long human isoform of CD45) phenotype. We analyzed patients with biopsy-proven localized Wegener's granulomatosis (WG) (n = 5), generalized WG (n = 16) and age- and sex-matched healthy controls (n = 13) to further characterize memory T cells in WG. The cell-surface expression of CD45RO, CD45RA, CD62L, CCR3, CCR5 and CXCR3 was determined on blood-derived T cells by four-color flow cytometric analysis. The fractions of CCR5⁺ and CCR3⁺ cells within the CD4⁺CD45RO⁺ and CD8⁺CD45RO⁺ memory T cell populations were significantly expanded in localized and generalized WG. The mean percentage of Th1-type CCR5 expression was higher in localized WG. Upregulated CCR5 and CCR3 expression could also be detected on a fraction of CD45RA⁺ T cells. CD62L expression was seen on approximately half of the memory T cell populations expressing chemokine receptors. This study demonstrates for the first time that expression of the inducible inflammatory chemokine receptors CCR5 and CCR3 on CD45RO⁺ memory T cells, as well as on CD45RA⁺ T cells ('revertants'), contributes to phenotypic heterogeneity in an autoimmune disease, namely WG. Upregulated CCR5 and CCR3 expression suggests that the cells belong to the effector memory T cell population. CCR5 and CCR3 expression on CD4⁺ and CD8⁺ memory T cells indicates a potential to respond to chemotactic gradients and might be important in T cell migration contributing to granuloma formation and vasculitis in WG.     

The Elevated Secreted Immunoglobulin D Enhanced the Activation of Peripheral Blood Mononuclear Cells in Rheumatoid Arthritis

Immunoglobulin D (IgD) is a surface immunoglobulin that is expressed as either membrane IgD (mIgD) or secreted IgD (sIgD). Researchers have shown that sIgD is often elevated in patients with autoimmune diseases. The possible roles of sIgD on the function of peripheral blood mononuclear cells (PBMCs) in rheumatoid arthritis (RA) are still unclear. In this study, we compared the expression of sIgD, mIgD and IgD receptor (IgDR) in RA patients and healthy controls, and investigated the effect of sIgD on the function of PBMCs. We found that the levels of sIgD, mIgD and IgDR were significantly higher in RA patients compared with healthy controls. The concentrations of sIgD were positively correlated with soluble receptor activator of nuclear factor-κB ligand (sRANKL), rheumatoid factor (RF) and C-reactive protein (CRP) in RA patients. Strikingly, IgD could enhance the proliferation of PBMCs and induce IL-1α, IL-1β, TNF-α, IL-6 and IL-10 production from PBMCs. Moreover, the percentage of activated T cell subsets (CD4⁺CD69⁺, CD4⁺CD154⁺) and activated B cell subsets (CD19⁺CD23⁺, CD19⁺CD21⁺, CD19⁺IgD⁺ and CD19^-CD138⁺) were increased by IgD. The percentage of unactivated T cell subset (CD4⁺CD62L⁺) and immature B cell subset (CD19⁺IgM⁺IgD^-) were decreased by IgD in PBMCs. Furthermore, the expressions of IgDR on T and B cells were significantly increased by treatment with IgD. Our results demonstrate that IgD enhanced the activation of PBMCs, which may contribute to RA pathogenesis. Therefore, IgD could be a potential novel immunotherapeutic target for the management of RA.     

Multiple Autoimmune-Associated Variants Confer Decreased IL-2R Signaling in CD4+CD25hi T Cells of Type 1 Diabetic and Multiple Sclerosis Patients

IL-2 receptor (IL-2R) signaling is essential for optimal stability and function of CD4⁺CD25^hiFOXP3⁺ regulatory T cells (Treg); a cell type that plays an integral role in maintaining tolerance. Thus, we hypothesized that decreased response to IL-2 may be a common phenotype of subjects who have autoimmune diseases associated with variants in the IL2RA locus, including T1D and MS, particularly in cells expressing the high affinity IL-2R alpha chain (IL-2RA or CD25). To examine this question we used phosphorylation of STAT5 (pSTAT5) as a downstream measure of IL-2R signaling, and found a decreased response to IL-2 in CD4⁺CD25^hi T cells of T1D and MS, but not SLE patients. Since the IL2RArs2104286 haplotype is associated with T1D and MS, we measured pSTAT5 in controls carrying the rs2104286 risk haplotype to test whether this variant contributed to reduced IL-2 responsiveness. Consistent with this, we found decreased pSTAT5 in subjects carrying the rs2104286 risk haplotype. Reduced IL-2R signaling did not result from lower CD25 expression on CD25^hi cells; instead we detected increased CD25 expression on naive Treg from controls carrying the rs2104286 risk haplotype, and subjects with T1D and MS. However the rs2104286 risk haplotype correlated with increased soluble IL-2RA levels, suggesting that shedding of the IL-2R may account in part for the reduced IL-2R signaling associated with the rs2104286 risk haplotype. In addition to risk variants in IL2RA, we found that the T1D-associated risk variant of PTPN2rs1893217 independently contributed to diminished IL-2R signaling. However, even when holding genotype constant at IL2RA and PTPN2, we still observed a significant signaling defect in T1D and MS patients. Together, these data suggest that multiple mechanisms converge in disease leading to decreased response to IL-2, a phenotype that may eventually lead to loss of tolerance and autoimmunity.     

Defective response of CD4(+) T cells to retinoic acid and TGFβ in systemic lupus erythematosus

Introduction  

CD25⁺ FOXP3⁺ CD4⁺ regulatory T cells (Tregs) are induced by transforming growth factor β (TGFβ) and further expanded by retinoic acid (RA). We have previously shown that this process was defective in T cells from lupus-prone mice expressing the novel isoform of the Pbx1 gene, Pbx1-d. This study tested the hypothesis that CD4⁺ T cells from systemic lupus erythematosus (SLE) patients exhibited similar defects in Treg induction in response to TGFβ and RA, and that PBX1-d expression is associated with this defect.     

B Cells Contribute to Heterogeneity of IL-17 Producing Cells in Rheumatoid Arthritis and Healthy Controls

Secretion of the proinflammatory cytokine Interleukin-17A (IL-17A) is the hallmark of a unique lineage of CD4 T cells designated Th17 cells, which may play a crucial role in the pathogenesis of rheumatoid arthritis (RA) and many autoimmune diseases. Recently, IL-17-producing cells other than T cells have been described, including diverse innate immune cells. Here, we show that the cellular sources of IL-17A in RA include a significant number of non-T cells. Multicolour fluorescence analysis of IL-17-expressing peripheral blood mononuclear cells (PBMC) revealed larger proportions of IL-17⁺CD3^- non-T cells in RA patients than in healthy controls (constitutive, 13.6% vs. 8.4%, and after stimulation with PMA/ionomycin 17.4% vs. 7.9% p < 0.001 in both cases). The source of IL-17 included CD3^-CD56⁺ NK cells, CD3^-CD14⁺ myeloid cells as well as the expected CD3⁺CD4⁺ Th17 cells and surprisingly a substantial number of CD3^-CD19⁺ B cells. The presence of IL-17A-expressing B cells was confirmed by specific PCR of peripheral MACS-sorted CD19⁺ B cells, as well as by the analysis of different EBV-transformed B cell lines. Here we report for the first time that in addition to Th17 cells and different innate immune cells B cells also contribute to the IL-17A found in RA patients and healthy controls.     

The expansion of CD4<Superscript>+</Superscript>CD28<Superscript>-</Superscript> T cells in patients with rheumatoid arthritis

Clonal expansion of CD4⁺CD28^- T cells is a characteristic finding in patients with rheumatoid arthritis (RA). Expanded CD4⁺ clonotypes are present in the peripheral blood, infiltrate into the joints, and persist for years. CD4⁺CD28^- T cells are oligoclonal lymphocytes that are rare in healthy individuals but are found in high percentages in patients with chronic inflammatory diseases. The size of the peripheral blood CD4⁺CD28^- T-cell compartment was determined in 42 patients with RA and 24 healthy subjects by two-color FACS analysis. The frequency of CD4⁺CD28^- T cells was significantly higher in RA patients than in healthy subjects. Additionally, the number of these cells was significantly higher in patients with extra-articular manifestations and advanced joint destruction than in patients with limited joint manifestations. The results suggest that the frequency of CD4⁺CD28^- T cells may be a marker correlating with extra-articular manifestations and joint involvement.     

Systemic analyses of immunophenotypes of peripheral T cells in non-segmental vitiligo: implication of defective natural killer T cells

Although it is widely believed that non‐segmental vitiligo (NSV) results from the autoimmune destruction of melanocytes, a clear understanding of defects in immune tolerance, which mediate this uncontrolled self‐reactivity, is still lacking. In the present study, we systemically evaluated circulating regulatory T (Treg) cells, including CD4⁺CD25⁺FoxP3⁺ Treg cells and invariant natural killer T (iNKT) cells, as well as naïve and memory CD4⁺ and CD8⁺ T cells and their cytokine production, in a cohort of 43 progressive NSV patients with race‐, gender‐, and age‐matched healthy controls. We found that the general immunophenotypes of CD4⁺ and CD8⁺ T cells and the percentage of CD4⁺CD25⁺FoxP3⁺ Tregs were comparable between NSV and healthy controls. However, percentages of peripheral iNKT cells were significantly decreased in NSV patients compared to that in healthy controls. Our data confirm the previous notion that the percentage of peripheral CD4⁺CD25⁺FoxP3⁺ Tregs remains unaltered in NSV and suggests the involvement of defective iNKT cells in the pathogenesis of NSV.     

Decreased regulatory T‐cells and CD4+/CD8+ ratio correlate with disease onset and progression in patients with generalized vitiligo

The aim of present study was to evaluate CD4⁺/CD8⁺ ratio and CD4⁺CD25^hiFoxP3⁺ Tregs in GV patients with reference to their effect on disease onset and progression. Flow cytometry was used for determination of CD4⁺/CD8⁺ ratio and Tregs in 82 patients and 50 controls. CD8⁺ T‐cell counts were significantly higher in GV patients as compared with controls (p = 0.003). Active GV patients showed higher CD8⁺ T‐cell counts compared with stable GV patients (p = 0.001). The CD4⁺/CD8⁺ ratio decreased significantly in patients as compared with controls (p = 0.001). Moreover, the ratio in active GV patients significantly lowered as compared with stable GV patients (p = 0.002). Significant decrease in Treg cell percentage and counts in GV patients was observed compared with controls (p = 0.009, p = 0.008) with significant reduction in FoxP3 expression (p = 0.024). Treg cell percentage and counts were significantly decreased in active GV patients compared with stable GV patients (p = 0.007, p = 0.002). Our results suggest that an imbalance of CD4⁺/CD8⁺ ratio and natural Tregs in frequency and function might be involved in the T‐cell mediated pathogenesis of GV and its progression.     

The role of LAIR-1 (CD305) in T cells and monocytes/macrophages in patients with rheumatoid arthritis

The LAIR-1 receptor is expressed on a majority of mononuclear leukocytes. It is used as a biomarker when testing synovial fluid for evidence of rheumatoid arthritis (RA). The primary objective of this study was to measure T cell- and monocyte/macrophage-specific LAIR-1 expression in RA patients and compare this to LAIR-1 expression in osteoarthritis (OA) patients and healthy individuals. LAIR-1 expression was significantly decreased in circulating CD4⁺ T cells in RA patients compared to both OA patients and healthy individuals. In contrast, LAIR-1 is high in CD14⁺ monocytes and local CD68⁺ macrophages in synovial tissues from RA patients. Upon stimulation with TNF-α, LAIR-1 expression decreased in T-helper (Th)1 and Th2 CD4⁺ T cells from healthy donors. These results indicate that LAIR-1 may exert different functions on T cells and monocytes/macrophages and suggest that LAIR-1 may be a novel therapeutic target for the treatment of RA.     

Decreased expression of microRNA‐21 correlates with the imbalance of Th17 and Treg cells in patients with rheumatoid arthritis

The imbalance of Th17/Treg cell populations has been suggested to be involved in the regulation of rheumatoid arthritis (RA) pathogenesis; however, the mechanism behind this phenomenon remains unclear. Recent studies have shown how microRNAs (miRNAs) are important regulators of immune responses and are involved in the development of a variety of inflammatory diseases, including RA. In this study, we demonstrated that the frequencies of CD3⁺CD4⁺IL‐17⁺Th17 cells were significantly higher, and CD4⁺CD25⁺FOXP3⁺ Treg cells significantly lower in peripheral blood mononuclear cells from RA patients. Detection of cytokines from RA patients revealed an elevated panel of pro‐inflammatory cytokines, including IL‐17, IL‐6, IL‐1β, TNF‐α and IL‐22, which carry the inflammatory signature of RA and are crucial in the differentiation and maintenance of pathogenic Th17 cells and dysfunction of Treg cells. However, the level of miR‐21 was significantly lower in RA patients, accompanied by the increase in STAT3 expression and activation, and decrease in STAT5/pSTAT5 protein and Foxp3 mRNA levels. Furthermore, lipopolysaccharide stimulation up‐regulated miR‐21 expression from healthy controls, but down‐regulated miR‐21 expression from RA patients. Therefore, we speculate that miR‐21 may be part of a negative feedback loop in the normal setting. However, miR‐21 levels decrease significantly in RA patients, suggesting that this feedback loop is dysregulated and may contribute to the imbalance of Th17 and Treg cells. MiR‐21 may thus serve as a novel regulator in T‐cell differentiation and homoeostasis, and provides a new therapeutic target for the treatment of RA.