Activation profile of Toll‐like receptors of peripheral blood lymphocytes in patients with systemic lupus erythematosus

Systemic lupus erythematosus (SLE) is a systemic autoimmune disease associated with aberrant activation of T and B lymphocytes for the production of inflammatory cytokines and autoreactive antibodies. Animal studies of SLE have indicated that Toll‐like receptors (TLR) are important in the pathogenesis of murine lupus. In the present clinical study, differential protein expressions of TLR‐1–9 of monocytes and different lymphocyte subsets from patients with SLE and normal control subjects were determined by flow cytometry. Results showed that the expression of intracellular TLRs (TLR‐3, ‐8, ‐9) and extracellular TLRs (TLR‐1, ‐2, ‐4, ‐5, ‐6) were elevated in monocytes, CD4⁺ T lymphocytes, CD8⁺ T lymphocytes and B lymphocytes of SLE patients compared to control subjects (all P < 0·001). Moreover, cell surface expression of TLR‐4 on CD4⁺ T lymphocytes and CD8⁺ T lymphocytes, and TLR‐6 on B lymphocytes, were correlated positively with SLE disease activity index (SLEDAI) (TLR‐4 on CD4⁺ T lymphocytes and CD8⁺ T lymphocytes: r = 0·536, P = 0·04; r = 0·713, P = 0·003; TLR‐6 in B lymphocytes: r = 0·572, P = 0·026). In concordance with the above results, there is an observable increased relative induction (%) of inflammatory cytokine interleukin (IL)‐1β, IL‐6, IL‐10 and IL‐12, chemokines CCL2, CXCL8, CCL5 and CXCL10 from peripheral blood mononuclear cells (PBMC) upon differential stimulation by PolyIC (TLR‐3 ligand), lipopolysaccharide (TLR‐4 ligand), peptidoglycan (TLR‐2 ligand), flagellin (TLR‐5 ligand), R837 (TLR‐7 ligand) and CpG DNA (TLR‐9 ligand) in SLE patients compared to controls. These results suggest that the innate immune response for extracellular pathogens and self‐originated DNA plays immunopathological roles via TLR activation in SLE.     

Rituximab‐induced interleukin‐15 reduction associated with clinical improvement in rheumatoid arthritis

Rituximab therapy alters all aspects of B‐cell participation in the disturbed immune response of rheumatoid arthritis patients. To determine the impact of B‐cell depletion on other immune compartments, we analysed levels of soluble and surface interleukin‐15 (IL‐15) along with the frequency of IL‐15‐related subsets after rituximab treatment. We then studied the correlation of observed changes with clinical activity. Heparinized blood samples from 33 rheumatoid arthritis patients were collected on days 0, 30, 90 and 180 after each of three rituximab cycles. Serum cytokine levels were determined by ELISA. Interleukin‐15 trans‐presentation was analysed by cytometry. Flow cytometry with monoclonal antibodies was performed to analyse circulating cell subsets. Interleukin‐15 was detected in the serum of 25 patients before initiating the treatment. Rituximab then progressively reduced serum IL‐15 (138 ± 21 pg/ml at baseline, 48 ± 18 pg/ml after third cycle, P = 0·03) along with IL‐17 (1197 ± 203 pg/ml at baseline, 623 ± 213 pg/ml after third cycle, P = 0·03) and tended to increase the frequency of circulating regulatory T cells (3·1 ± 1 cells/μl at baseline, 7·7 ± 2 cells/μl after third cycle). Rituximab also significantly decreased IL‐15 trans‐presentation on surface monocytes of patients negative for IL‐15 serum (mean fluorescence intensity: 4·82 ± 1·30 at baseline, 1·42 ± 0·69 after third cycle P = 0·05). Reduction of serum IL‐15 was associated with decrease in CD8⁺ CD45RO⁺/RA⁺ ratio (1·17 ± 0·21 at baseline, 0·36 ± 0·06 at third cycle, P = 0·02). DAS28, erythrocyte sedimentation rate and C‐reactive protein correlated significantly with CD8⁺ CD45RO⁺/RA⁺ ratio (R = 0·323, R = 0·357, R = 0·369 respectively, P < 0·001). Our results suggest that sustained clinical improvement after rituximab treatment is associated with IL‐15/memory T‐cell‐related mechanisms beyond circulating B cells.     

Ro52/TRIM21‐deficient expression and function in different subsets of peripheral blood mononuclear cells is associated with a proinflammatory cytokine response in patients with idiopathic inflammatory myopathies

The presence of anti‐Ro52/tripartite motif 21 (Trim21) autoantibodies has been associated with a distinctive clinical profile and has gained value as a prognostic marker in idiopathic inflammatory myopathies (IIM). The aim of the present work was to analyse Ro52/Trim21 expression in different subsets of peripheral blood mononuclear cells (PBMCs) of patients with IIM, as well as the ubiquitination profile and its association with proinflammatory cytokine production. We included 18 patients with recent‐onset IIM and 18 age‐ and gender‐matched healthy donors. PBMCs were isolated and different subsets (CD4⁺, CD8⁺, CD14⁺) were purified by magnetic selection. The expression of Ro52/Trim21 in different PBMC subsets of patients with IIM and healthy donors was analysed by Western blot. We assessed the presence of myositis‐specific and associated autoantibodies by enzyme‐linked immunosorbent assay (ELISA). Cytokine levels were measured by cytometric bead array. Patients with IIM showed decreased protein expression of Ro52/Trim21 in comparison to healthy controls in PBMC (0·97 ± 0·60 versus 1·84 ± 0·92, P = 0·016), CD4⁺ lymphocytes (0·79 ± 0·54 versus 2·41 ± 0·78, P = 0·017), and monocytes (0·87 ± 0·35 versus 1·89 ± 0·20, P < 0·001). There were no significant differences among IIM groups. Also, a lower K48‐mediated ubiquitination profile was found, predominantly in CD4⁺ lymphocytes. Furthermore, after mitogenic stimulation, there was a higher synthesis of proinflammatory cytokines by T cells [interleukin (IL)‐17A and tumour necrosis factor (TNF)‐α] and monocytes [IL‐6 and interferon (IFN)‐α] from IIM patients compared with healthy controls. Our data suggest that patients with IIM, mainly DM, are characterized by a deficient expression of Ro52/TRIM21 in different PBMC subsets (CD4⁺ lymphocytes and monocytes), along with lower K48‐mediated ubiquitination, which is associated with a proinflammatory cytokine response.     

Evaluation of membrane‐bound and soluble forms of human leucocyte antigen‐G in systemic sclerosis

Systemic sclerosis (SSc) is a complex disease characterized by immune dysregulation, extensive vascular damage and widespread fibrosis. Human leucocyte antigen‐G (HLA‐G) is a non‐classic class I major histocompatibility complex (MHC) molecule characterized by complex immunomodulating properties. HLA‐G is expressed on the membrane of different cell lineages in both physiological and pathological conditions. HLA‐G is also detectable in soluble form (sHLA‐G) deriving from the shedding of surface isoforms (sHLA‐G1) or the secretion of soluble isoforms (HLA‐G5). Several immunosuppressive functions have been attributed to both membrane‐bound and soluble HLA‐G molecules. The plasma levels of sHLA‐G were higher in SSc patients (444·27 ± 304·84 U/ml) compared to controls (16·74 ± 20·58 U/ml) (P < 0·0001). The plasma levels of transforming growth factor (TGF)‐β were higher in SSc patients (18 937 ± 15 217 pg/ml) compared to controls (11 099 ± 6081 pg/ml; P = 0·003), and a significant correlation was found between TGF‐β and the plasma levels of total sHLA‐G (r = 0·65; P < 0·01), sHLA‐G1 (r = 0·60; P = 0·003) and HLA‐G5 (r = 0·47; P = 0·02). The percentage of HLA‐G‐positive monocytes (0·98 ± 1·72), CD4⁺ (0·37 ± 0·68), CD8⁺ (2·05 ± 3·74) and CD4⁺CD8⁺ double‐positive cells (14·53 ± 16·88) was higher in SSc patients than in controls (0·11 ± 0·08, 0·01 ± 0·01, 0·01 ± 0·01 and 0·39 ± 0·40, respectively) (P < 0·0001). These data indicate that in SSc the secretion and/or shedding of soluble HLA‐G molecules and the membrane expression of HLA‐G by peripheral blood mononuclear cells (PBMC) is clearly elevated, suggesting an involvement of HLA‐G molecules in the immune dysregulation of SSc.     

CD14 expression is increased on monocytes in patients with anti‐neutrophil cytoplasm antibody (ANCA)‐associated vasculitis and correlates with the expression of ANCA autoantigens

Monocyte subsets with differing functional properties have been defined by their expression of CD14 and CD16. We investigated these subsets in anti‐neutrophil cytoplasm antibody (ANCA)‐associated vasculitis (AAV) and determined their surface expression of ANCA autoantigens. Flow cytometry was performed on blood from 14 patients with active AAV, 46 patients with AAV in remission and 21 controls. The proportion of classical (CD14^highCD16^neg/low), intermediate (CD14^highCD16^high) and non‐classical (CD14^lowCD16^high) monocytes and surface expression levels of CD14 and CD16 were determined, as well as surface expression of proteinase 3 (PR3) and myeloperoxidase (MPO) on monocyte subsets. There was no change in the proportion of monocytes in each subset in patients with AAV compared with healthy controls. The expression of CD14 on monocytes from patients with active AAV was increased, compared with patients in remission and healthy controls (P < 0·01). Patients with PR3‐ANCA disease in remission also had increased monocyte expression of CD14 compared with controls (P < 0·01); however, levels in patients with MPO‐ANCA disease in remission were lower than active MPO‐ANCA patients, and not significantly different from controls. There was a correlation between CD14 and both PR3 and MPO expression on classical monocytes in AAV patients (r = 0·79, P < 0·0001 and r = 0·42, P < 0·005, respectively). In conclusion, there was an increase in monocyte CD14 expression in active AAV and PR3‐ANCA disease in remission. The correlation of CD14 expression with ANCA autoantigen expression in AAV may reflect cell activation, and warrants further investigation into the potential for increased CD14 expression to trigger disease induction or relapse.     

Intermediate monocytes are increased in enthesitis‐related arthritis,a category of juvenile idiopathic arthritis

Microarray of peripheral blood (PB) and synovial fluid mononuclear cells (PBMC, SFMC) of patients with juvenile idiopathic arthritis–enthesitis‐related arthritis (JIA‐ERA) has shown the involvement of monocytes. On the basis of CD14 and CD16 expression, monocytes are classified as classical, intermediate and non‐classical. In response to Toll‐like receptor (TLR) stimulation, intermediate monocytes produce proinflammatory cytokines and play a role in inflammatory diseases. Therefore, we have studied the microarray profile of monocytes, the frequency of their subsets and cytokine production. Monocyte‐specific microarray analysis was performed in six healthy controls' PBMC and six patients' PBMC and SFMC using Illumina chips WG12. Monocyte subsets were assessed in 46 patients with JIA‐ERA and 17 healthy controls and 17 disease controls by flow cytometry. Interleukin (IL)?23 and tumour necrosis factor (TNF) levels were measured in culture supernatants of eight controls and seven patients' PBMC/SFMC with/without lipopolysaccharide (LPS) stimulation. Cytokine‐producing intermediate monocytes were assessed by flow cytometry. Genes related to antigen presentation, cytokine signalling and TLR pathway were regulated differentially in PB and synovial monocytes of patients with JIA‐ERA. Key genes of intermediate monocytes, such as CLEC10A and MARCO, were expressed three‐ to fourfold more in JIA‐ERA. In PB, the frequency of intermediate monocytes was significantly higher in JIA‐ERA (4·90% ± 3·5) compared to controls (1·8% ± 1·06; P < 0·001). Patients' synovial cells also had more intermediate monocytes compared to PB (11·25% ± 11·32, 5·9% ± 4·8; P = 0.004). Intermediate monocytes are the major producers of IL‐23. Thus, intermediate monocytes may play an important role in JIA‐ERA, possibly by producing cytokines, and contribute to joint inflammation.     

Unicompartmental and bicompartmental knee osteoarthritis show different patterns of mononuclear cell infiltration and cytokine release in the affected joints

It is still controversial which cell types are responsible for synovial inflammation in osteoarthritic (OA) joints. The aim of this study was to quantify the mononuclear cell populations and their cytokines in patients with different knee OA subtypes. Synovial membrane (SM), synovial fluid (SF) and peripheral blood (PB) were harvested from patients with unicompartmental (UC) and bicompartmental (BC) knee OA. Frequencies of mononuclear cells were assessed by flow cytometry in PB and SM. Naive SF samples were analysed for a broad variety of cytokines by multiplex analysis. SM of both groups displayed a distinct mononuclear cell infiltration, with CD14⁺ macrophages being the major cell population, followed by CD4⁺ T cells and only small numbers of CD8⁺ T, CD19⁺ B and CD16⁺CD56⁺ natural killer (NK) cells. Between the two groups, SM of BC OA showed significantly higher amounts of mononuclear cells (135·7 ± 180 versus 805 ± 675 cells/mg, P = 0·0009) and higher CD4⁺ T cell presence (3·4 ± 4·6 versus 9·1 ± 7·5%, P = 0·0267). SF of BC OA displayed significantly higher concentrations for a number of proinflammatory cytokines [CXCL1, eotaxin, interferon (IFN)‐γ, interleukin (IL)‐7, IL‐8, IL‐9, IL‐12]. UC and BC OA show significant differences in their synovial inflammatory pattern. Whereas in UC OA CD14⁺ macrophages are the predominant cell population, BC OA has a higher inflammatory profile and seems to be driven by CD14⁺ macrophages and CD4⁺ T cells. Inclusion of clinical information into the analysis of cellular and molecular results is pivotal in understanding the pathophysiology of OA.     

Role of inflammatory cells, cytokines and matrix metalloproteinases in neutrophil-mediated skin diseases

Pyoderma gangrenosum (PG) is a rare, immune‐mediated inflammatory skin disease presenting with painful ulcers having undermined edges. Less commonly, bullous and vegetative variants exist. Histology consists of a neutrophil‐rich dermal infiltrate. We characterized immunohistochemically the infiltrate in different variants of PG and in another neutrophilic dermatosis as Sweet's syndrome. We studied 21 patients with PG, eight with Sweet's syndrome and 20 controls, evaluating skin immunoreactivity for inflammatory cell markers (CD3, CD163 and myeloperoxidase), cytokines [tumour necrosis factor (TNF)‐α, interleukin (IL)‐8 and IL‐17], metalloproteinases (MMP‐2 and MMP‐9) and vascular endothelial growth factor (VEGF). Immunoreactivities of CD3, CD163, myeloperoxidase, TNF‐α, IL‐8, IL‐17, MMP‐2, MMP‐9 and VEGF were significantly higher in both PG and Sweet's syndrome than in controls (P = 0·0001). Myeloperoxidase (neutrophil marker), IL‐8 (cytokine chemotactic for neutrophils) and MMP‐9 (proteinase‐mediating tissue damage) were expressed more significantly in both ulcerative and bullous PG than in vegetative PG as well as in Sweet's syndrome (P = 0·008–P = 0·0001). In ulcerative PG, the expression of CD3 (panT cell marker) and CD163 (macrophage marker) were significantly higher in wound edge than wound bed (P = 0·0001). In contrast, the neutrophil marker myeloperoxidase was expressed more significantly in wound bed than wound edge (P = 0·0001). Our study identifies PG as a paradigm of neutrophil‐mediated inflammation, with proinflammatory cytokines/chemokines and MMPs acting as important effectors for the tissue damage, particularly in ulcerative and bullous PG where damage is stronger. In ulcerative PG, the wound bed is the site of neutrophil‐recruitment, whereas in the wound edge activated T lymphocytes and macrophages pave the way to ulcer formation.     

Programmed death‐1+ T cells inhibit effector T cells at the pathological site of miliary tuberculosis

Optimal T cell activation is vital for the successful resolution of microbial infections. Programmed death‐1 (PD‐1) is a key immune check‐point receptor expressed by activated T cells. Aberrant/excessive inhibition mediated by PD‐1 may impair host immunity to Mycobacterium tuberculosis infection, leading to disseminated disease such as miliary tuberculosis (MTB). PD‐1 mediated inhibition of T cells in pulmonary tuberculosis and TB pleurisy is reported. However, their role in MTB, particularly at the pathological site, remains to be addressed. The objective of this study was to investigate the role of PD‐1–PD‐ligand 1 (PD‐L1) in T cell responses at the pathological site from patients of TB pleurisy and MTB as clinical models of contained and disseminated forms of tuberculosis, respectively. We examined the expression and function of PD‐1 and its ligands (PD‐L1–PD‐L2) on host immune cells among tuberculosis patients. Bronchoalveolar lavage‐derived CD3 T cells in MTB expressed PD‐1 (54·2 ± 27·4%, P ≥ 0·0009) with significantly higher PD‐1 ligand‐positive T cells (PD‐L1: 19·8 ± 11·8%; P ≥ 0·019, PD‐L2: 12·6 ± 6·2%; P ≥ 0·023), CD19⁺ B cells (PD‐L1: 14·4 ± 10·4%; P ≥ 0·042, PD‐L2: 2·6 ± 1·43%; not significant) and CD14⁺ monocytes (PD‐L1: 40·2 ± 20·1%; P ≥ 0·047, PD‐L2: 22·4 ± 15·6%; P ≥ 0·032) compared with peripheral blood (PB) of MTB and healthy controls. The expression of PD‐1 was associated with a diminished number of cells producing effector cytokines interferon (IFN)‐γ, tumour necrosis factor (TNF)‐α, interleukin (IL)?2 and elevated apoptosis. Locally accumulated T cells were predominantly PD‐1⁺–PD‐L1⁺, and blocking this pathway restores the protective T cell response. We conclude that M. tuberculosis exploits the PD‐1 pathway to evade the host immune response by altering the T helper type 1 (Th1) and Th2 balance at the pathological site of MTB, thereby favouring disease dissemination.     

Changes in the levels of some acute-phase proteins in human immunodeficiency virus-1 infected patients, following interleukin-2 treatment

Intermittent interleukin (IL)‐2 administration to human immunodeficiency virus (HIV)‐1 infected patients is well documented and generally used, but there is limited information about the changes of acute‐phase protein (APP) levels in response to this treatment. Fifteen patients undergoing highly active anti‐retroviral therapy (HAART) treatment, with undetectable viral load, but low CD4⁺ cell count (<300/µl), have been treated with 3·6 M IU Proleukine® administered twice daily by subcutaneous injection over 5 days. C‐reactive protein (CRP), d ‐dimer, C3, C9, C1‐inh and alpha‐2HS glycoprotein levels were measured immediately before IL‐2 administration, as well as on day 5 and 2–3 weeks thereafter. After IL‐2 administration, both mean d ‐dimer and CRP levels increased significantly (P < 0·001), but returned (P < 0·001) to baseline within the subsequent 2–3 weeks. Alpha‐2HS glycoprotein decreased immediately after IL‐2 administration. No significant differences were detected in the levels of C3, C9 and C1‐inh. A significant, positive correlation (r = 0·5178, P = 0·0008) was ascertained between the changes of CRP level, measured immediately before as well as 5 days after IL‐2 administration, and changes in CD4 T cell counts measured 2–3 weeks before and after treatment, respectively. IL‐2 administration induces rapid elevation of two major APPs (CRP, d ‐dimer). The positive correlation observed between the changes of CRP levels and CD4⁺ cell counts after IL‐2 administration may indicate that the abrupt, but transitory overproduction of CRP might contribute to the CD4⁺ cell count‐increasing effect of the drug and/ or may be associated with serious side effects.     

Low numbers of CD8+ T lymphocytes in hereditary haemochromatosis are explained by a decrease of the most mature CD8+ effector memory T cells

Low CD8⁺ T lymphocyte numbers have long been described in hereditary haemochromatosis (HH). Recently, two conserved haplotypes localized near the microsatellite D6S105 at the major histocompatibility complex (MHC) class I region were described predicting the clinical expression of HH and the CD8⁺ T lymphocyte numbers. The A‐A‐T haplotype was associated with a severe clinical expression of HH and low CD8⁺ T lymphocyte numbers, while the G‐G‐G haplotype was associated with a milder clinical expression of HH and high CD8⁺ T lymphocyte numbers. As CD8⁺ T lymphocytes are a very heterogeneous population, in this study we analysed the CD8⁺ subpopulations of naive, central memory (T_CM) and effector memory (T_EM), and further subsets of CD8⁺ T_EM cells in 47 HH patients and 68 controls. In addition, association studies were conducted between the conserved haplotypes and the CD8⁺ T cell subpopulations in HH. Variations of the numbers of naive and central memory cells with age were similar between HH patients and controls. For T_EM cells and the T_EM CD27^‐CD28^‐ subset no effect of age was observed in HH [R² = 0·001, not significant (n.s.) and R² = 0·01, n.s., respectively] contrasting with the increasing of these subpopulations with age in controls (R² = 0·09, P = 0·017 and R² = 0·22, P = 0·0005, respectively). Interestingly, patients homozygous for the A‐A‐T haplotype have lower numbers of CD8⁺ T_EM cells due especially to lower numbers of T_EM CD27^‐CD28^‐ (0·206 ± 0·119 and 0·066 ± 0·067 × 10⁶ cells/ml, respectively) than patients carrying the G‐G‐G haplotype (0·358 ± 0·195 and 0·246 ± 0·202 × 10⁶ cells/ml, respectively). This may suggest an inability of HH patients to differentiate the CD8⁺ T cells into the most mature phenotype.     

The effects of Mycobacteria vaccae derivative on allergen-specific responses in children with atopic dermatitis

The capacity of microbial products to inhibit allergic inflammation make them logical candidates for novel therapies in allergic diseases such as atopic dermatitis. To assess the effects of intradermal Mycobacterium vaccae derivative on allergen‐specific immune responses in children with moderate to severe atopic dermatitis. Peripheral blood mononuclear cells were isolated from children aged 5–16 years who received intradermal injections of M. vaccae derivative AVAC^TM (n = 26) or placebo (n = 34) three times at 2‐weekly intervals, weeks 0, 2 and 4. Cytokine [interleukin (IL)‐13, interferon (IFN)‐γ and IL‐10] responses to allergen [house dust mite (HDM)], mitogen [phytohaemagglutinin (PHA)], Staphylococcal enterotoxin B (SEB) and Toll‐like receptor (TLR) ligands were assessed. At week 8 (1 month after all injections given) children in the AVAC group showed a significant increase in IL‐10 (P = 0·009), T helper type 1 (Th1) IFN‐γ (P = 0·017) and Th2 IL‐13 (P = 0·004) responses to HDM compared with baseline (week 0). There were no significant changes in any cytokine production in the placebo. HDM‐specific IL‐10 responses remained significantly higher (P = 0·014) than at baseline in the AVAC group by week 12; however, the HDM‐specific IL‐13 and IFN‐γ responses were no longer significantly different from baseline. IL‐13 (r = 0·46, P < 0·001) and IL‐10 (r = 0·27, P = 0·044) responses to HDM were correlated with total immunoglobulin E but not with disease severity. There were no effects of AVAC on mitogen, SEB, TLR‐2‐ or TLR‐4‐mediated responses. This M. vaccae derivative appeared to modulate responses to HDM selectively, suggesting the capacity for in vivo effects on allergen‐specific immune responses.     

The level of urinary secretory immunoglobulin A (sIgA) of patients with IgA nephropathy is elevated and associated with pathological phenotypes

Recent studies have demonstrated deposition of secretory immunoglobulin A (sIgA) in glomeruli of some patients with IgA nephropathy (IgAN). The aim of this study is to investigate the levels of urinary sIgA in IgAN patients with different pathological phenotypes and whether it could be used as a non‐invasive biomarker for assessment of kidney injury in IgAN. Urine samples from 202 patients with IgAN were collected on the day of renal biopsy. Forty‐eight fulfilled the histopathological criteria of Haas‐I or II (group 1), 60 fulfilled Haas‐III (group 2) and 94 patients fulfilled Haas‐IV or V (group 3). Urine samples from 60 healthy sex‐ and age‐matched volunteers with negative urinalysis were collected as normal controls. Urinary sIgA was detected by sandwich enzyme‐linked immunosorbent assay and was corrected by urinary creatinine. In comparison with normal controls, the levels of urinary sIgA were significantly higher in IgAN [2·22 (0–43·82) μg/mg Cr versus 1·08 (0–16·49) μg/mg Cr, P < 0·001]. The levels of urinary sIgA were significantly higher in group 3 than that in group 2 and group 1 [3·54 (0–43·82) μg/mg Cr versus 1·63 (0–15·88) μg/mg Cr versus 0·91 (0–11·79), P < 0·001], and group 2 than group 1 (P = 0·014). The levels of urinary sIgA were associated positively with proteinuria (r = 0·443, P < 0·001), serum creatinine (r = 0·376, P < 0·001) and histopathological parameters, such as ratio of global sclerosis (r = 0·356, P < 0·001), ratio of total crescents (r = 0·339, P < 0·001) and ratios of cellular crescents (r = 0·231, P < 0·001). The levels of urinary sIgA were associated closely with histopathological phenotypes of IgAN and might be used as a non‐invasive biomarker to evaluate kidney injury in IgAN.     

Down syndrome, autoimmunity and T regulatory cells

Autoimmune diseases are more represented in Down syndrome (DS) individuals compared to chromosomally normal people. Natural T regulatory cells (nT_reg) have been considered to be primary in the role of controlling the intensity and targets of the immune response. We have investigated the phenotypical and functional alteration of nT_reg in a group of DS people. The phenotypical characteristic of T_reg cells of 29 DS was analysed and compared with an age‐matched healthy control group. The inhibitory potential of CD4⁺CD25^highCD127^low T regulatory cells was evaluated on autologous CD4⁺CD25^‐ T cell proliferation in response to activation with a mytogenic pan‐stimulus (anti‐CD2, anti‐CD3 and anti‐CD28 antibodies). The CD4⁺CD25^high cells in the DS and control groups were 2·692 ± 0·3808%, n = 29 and 1·246 ± 0·119, n = 29%, respectively (P = 0.0007), with a percentage of forkhead box protein 3 (FoxP3)‐expressing cells of 79·21 ± 3·376%, n = 29 and 59·75 ± 4·496%, respectively (P = 0.0015). CD4⁺CD25⁺FoxP3⁺ cells were increased in peripheral blood from DS subjects (DS mean 5·231 ± 0·6065% n = 29, control mean 3·076 ± 0·3140% n = 29). The majority of CD4⁺CD25^high were CD127^low and expressed a high percentage of FoxP3 (natural T_reg phenotype). While the proliferative capacity of DS T cells was not altered significantly compared to normal individuals, a reduced inhibitory potential of T_reg compared to healthy controls was clearly observed (mean healthy control inhibition in T_eff : T_reg 1:1 co‐culture: 58·9% ± 4·157%, n = 10 versus mean DS inhibition in T_eff : T_reg 1:1 co‐culture: 39·8 ± 4·788%, n = 10, P = 0.0075; mean healthy control inhibition in T_eff : T_reg 1:0·5 co‐culture: 45·10 ± 5·858%, n = 10 versus DS inhibition in T_eff : T_reg 1:0·5 co‐culture: 24·10 ± 5·517%, n = 10, P = 0.0177). DS people present an over‐expressed peripheral nT_reg population with a defective inhibitory activity that may partially explain the increased frequency of autoimmune disease.     

Increased CTLA‐4+ T cells may contribute to impaired T helper type 1 immune responses in patients with chronic obstructive pulmonary disease

Impaired T helper type 1 (Th1) function is implicated in the susceptibility of patients with chronic obstructive pulmonary disease (COPD) to respiratory infections, which are common causes of acute exacerbations of COPD (AECOPD). To understand the underlying mechanisms, we assessed regulatory T (Treg) cells and the expression of an inhibitory T‐cell receptor, cytotoxic T‐lymphocyte‐associated antigen 4 (CTLA‐4). Cryopreserved peripheral blood mononuclear cells (PBMC) from patients with AECOPD (n = 17), patients with stable COPD (sCOPD; n = 24) and age‐matched healthy non‐smoking controls (n = 26) were cultured for 24 hr with brefeldin‐A or monensin to detect intracellular or surface CTLA‐4 (respectively) by flow cytometry. T cells in PBMC from AECOPD (n = 9), sCOPD (n = 14) and controls (n = 12) were stimulated with anti‐CD3 with and without anti‐CTLA‐4 blocking antibodies and cytokines were quantified by ELISA. Frequencies of circulating T cells expressing intracellular CTLA‐4 were higher in sCOPD (P = 0·01), whereas patients with AECOPD had more T cells expressing surface CTLA‐4 than healthy controls (P = 0·03). Increased frequencies of surface CTLA‐4⁺ CD4⁺ T cells and CTLA‐4⁺ Treg cells paralleled increases in plasma soluble tumour necrosis factor receptor‐1 levels (r = 0·32, P = 0·01 and r = 0·29, P = 0·02, respectively) in all subjects. Interferon‐γ responses to anti‐CD3 stimulation were inversely proportional to frequencies of CD4⁺ T cells expressing intracellular CTLA‐4 (r = −0·43, P = 0·01). Moreover, CTLA‐4 blockade increased the induction of interferon‐γ, tumour necrosis factor‐α and interleukin‐6 in PBMC stimulated with anti‐CD3. Overall, chronic inflammation may expand sub‐populations of T cells expressing CTLA‐4 in COPD patients and therefore impair T‐cell function. CTLA‐4 blockade may restore Th1 function in patients with COPD and so aid the clearance of bacterial pathogens responsible for AECOPD.     

CD16+ monocytes in breast cancer patients: expanded by monocyte chemoattractant protein-1 and may be useful for early diagnosis

Human peripheral blood monocytes are a heterogeneous population, including CD14⁺CD16^‐‘classical’ monocytes and CD14⁺CD16⁺‘proinflammatory’ monocytes. CD16⁺ monocytes are expanded in various inflammatory conditions. However, little is known about the CD14⁺CD16⁺ monocytes in patients with breast cancer. We detected CD14⁺CD16⁺ monocytes in 96 patients with breast cancer and 54 control subjects using flow cytometry. Receiver‐operating characteristic (ROC) curve analysis was used to determine the feasibility of CD14⁺CD16⁺ monocytes as an indicator for diagnosis of breast cancer. We found that the frequency of CD14⁺CD16⁺ monocytes showed a significantly greater increase in breast cancer patients than in controls (16·96% versus 10·84%, P < 0·0001). The area under the ROC curve for CD14⁺CD16⁺ monocytes was 0·805 [95% confidence interval (95% CI): 0·714–0·877, P = 0·0001]. Furthermore, the levels of CD16⁺ monocytes were significantly negatively associated with the tumour size and pathological staging. In vitro, we showed that CD14⁺CD16⁺ monocytes were expanded significantly when the purified CD14⁺ monocytes were exposed to Michigan Cancer Foundation (MCF)‐7 cells‐conditioned medium (MCF‐CM) or, separately, to monocyte chemotactic protein 1 (MCP‐1). Neutralizing antibodies against MCP‐1 inhibited the expansion of CD14⁺CD16⁺ monocytes by MCF‐CM. Collectively, our findings indicated that MCP‐1 can expand CD14⁺CD16⁺ monocytes in patients with breast cancer. Furthermore, the CD14⁺CD16⁺ monocyte may be a useful indicator in early diagnosis of breast cancer.     

T cell activation profiles in different granulomatous interstitial lung diseases – a role for CD8+CD28null cells?

Lymphocytes play a crucial role in lung inflammation. Different interstitial lung diseases may show distinct lymphocyte activation profiles. The aim of this study was to examine the expression of a variety of activation markers on T lymphocyte subsets from blood and bronchoalveolar lavage fluid (BALF) of patients with different granulomatous interstitial lung diseases and healthy controls. Bronchoalveolar lavage cells and blood cells from 23 sarcoidosis patients, seven patients with hypersensitivity pneumonitis and 24 healthy controls were analysed. Lymphocyte activation status was determined by flow cytometry. Lymphocytes were stained with antibodies against CD3, CD4, CD8, CD25, CD28, CD69, very late antigen‐1 (VLA)‐1, VLA‐4 and human leucocyte antigen D‐related (HLA‐DR). In general, CD28, CD69 and VLA‐1 expression on BALF CD4⁺ lymphocytes and HLA‐DR expression on BALF CD8⁺ lymphocytes was different in patients with hypersensitivity pneumonitis and sarcoidosis patients with parenchymal involvement. This BALF lymphocyte phenotype correlated with carbon monoxide diffusing lung capacity (Dlco) values across interstitial lung diseases (ILD) (r² = 0·48, P = 0·0002). In sarcoidosis patients, CD8⁺CD28^null blood lymphocytes correlated with lower Dlco values (r = ?0·66, P = 0·004), chronic BALF lymphocyte activation phenotype (r² = 0·65, P < 0·0001), radiographic staging (stage I versus stage II and higher, P = 0·006) and with the need for corticosteroid treatment (P = 0·001). Higher expression of CD69, VLA‐1 and HLA‐DR and lower expression of CD28 on BALF lymphocytes suggests prolonged stimulation and chronic lymphocyte activation in patients with ILD. In sarcoidosis, blood CD8⁺CD28^null cells might be a new biomarker for disease severity but needs further investigation.     

Expression of interleukin (IL)‐19 and IL‐24 in inflammatory bowel disease patients: a cross‐sectional study

Interleukin (IL)‐19 and IL‐24 belong to the IL‐20 subfamily, and are involved in host defence against bacteria and fungi, tissue remodelling and wound healing. Nevertheless, no previous studies have explored their expression in Mexican mestizo patients with inflammatory bowel disease (IBD). The aim of the study was to characterize and to enumerate peripheral and tissue IL‐19‐ and IL‐24‐producing cells, as well as gene expression in patients with IBD with regard to its clinical activity. We studied a total of 77 patients with ulcerative colitis (UC), 36 Crohn's disease (CD) and 33 patients as control group (without endoscopic evidence of intestinal inflammation). Gene expression was measured by real‐time–polymerase chain reaction (RT–PCR). Protein expression was detected in biopsies by immunohistochemistry and in freshly isolated peripheral blood mononuclear cells by flow cytometry. IL‐19 and IL‐24 gene expression was elevated significantly in patients with active IBD versus the inactive disease and non‐inflammatory control groups (P < 0·05). However, IL‐19‐ and IL‐24‐producing cells were only increased in active CD versus active UC and non‐inflammatory tissues (P < 0·05). IL‐19 was produced conspicuously by circulating B cells and monocytes in patients with inactive disease (P < 0·05). Conversely, IL‐24 was noticeably synthesized by peripheral B cells, CD4⁺ T cells, CD8⁺ T cells and monocytes in patients with active disease. In conclusion, IL‐19‐ and IL‐24‐producing cells in active CD patients were increased compared with active UC and non‐inflammatory tissues. These cytokines could significantly shape and differentiate inflammatory process, severity and tolerance loss between UC and CD pathophysiology.