CD4+ T cells producing interleukin (IL)‐17, IL‐22 and interferon‐γ are major effector T cells in nickel allergy

Background It has been suggested that interleukin (IL)‐17 and IL‐22 play important roles in the elicitation of human allergic contact dermatitis; however, the frequencies of T cell subtypes producing IL‐17 and IL‐22 in human allergic contact dermatitis are unknown. Objectives To determine the frequencies of CD4⁺, CD8⁺ and γδ T cells producing IL‐17, IL‐22 and interferon (IFN)‐γ in the blood and skin from nickel‐allergic patients. Patients/materials/methods Blood samples were collected from 14 patients and 17 controls, and analysed by flow cytometry. Biopsies were taken from 5 patients and 6 controls, and analysed by immunohistochemistry and flow cytometry of skin lymphocytes. Results We found an increased frequency of γδ T cells in the blood, but no differences in the distribution of cytokine‐producing CLA⁺ T cell subtypes in nickel‐allergic patients as compared with controls. In nickel‐allergic patients, there was massive cellular infiltration dominated by CD4⁺ T cells producing IL‐17, IL‐22 and IFN‐γ in nickel‐challenged skin but not in vehicle‐challenged skin. Conclusion CD4⁺ T cells producing IL‐17, IL‐22 and IFN‐γ are important effector cells in the eczematous reactions of nickel‐induced allergic contact dermatitis in humans.     

Effective induction of melanoma‐antigen‐specific CD8+ T cells via Vγ9γδT cell expansion by CD56high+ Interferon‐α‐induced dendritic cells

Dendritic cells (DCs) can be differentiated from CD14⁺ monocytes in the presence of interferon‐α (IFNα) and granulocyte/macrophage‐colony stimulating factor (GM‐CSF) in vitro and are known as IFN‐DCs. Circulating blood CD56⁺ cells expressing high levels of CD14, HLA‐DR and CD86 have been shown to spontaneously differentiate into DC‐like cells in vitro after their isolation from blood. We show here that IFN‐DCs expressing high levels of CD56 (hereafter, CD56^high+ IFN‐DCs) can be differentiated in vitro from monocytes obtained as adherent cells from healthy donors and patients with metastatic melanoma. These cells expressed high levels of CD14, HLA‐DR and CD86 and possessed many pseudopodia. These CD56^high+ IFN‐DCs may be an in vitro counterpart of the circulating CD56⁺ CD14⁺ CD86⁺ HLA‐DR⁺ cells in blood. Conventional mature DCs differentiated from monocytes as adherent cells in the presence of GM‐CSF, IL‐4 and TNF‐α (hereafter, mIL‐4DCs) did not express CD56 or CD14. In contrast to mIL‐4DCs, the CD56^high+ IFN‐DCs exhibited a stronger capacity to stimulate autologous CD56⁺ Vγ9γδT cells highly producing IFNγ in the presence of zoledronate and IL‐2. The CD56^high+ IFN‐DCs possessing HLA‐A*0201 effectively induced Mart‐1‐modified melanoma peptide (A27L)‐specific CD8⁺ T cells through preferential expansion of CD56⁺ Vγ9γδT cells in the presence of A27L, zoledronate and IL‐2. Vaccination with CD56^high+ IFN‐DCs copulsed with tumor antigens and zoledronate may orchestrate the induction of various CD56⁺ immune cells possessing high effector functions, resulting in strong immunological responses against tumor cells. This study may be relevant to the design of future clinical trials of CD56^high+ IFN‐DCs‐based immunotherapies for patients with melanoma.     

Serum Th1/Th2 and macrophage lineage cytokines in leprosy; correlation with circulating CD4+ CD25highFoxP3+ T‐regs cells

Not only macrophages, T‐helper (Th)1 and Th2, but also CD4⁺ CD25^highFoxP3⁺ regulatory T cells (T‐regs) are involved in immune response to Mycobacterium leprae. We aimed to evaluate serum interleukin (IL)‐1β and IL‐12p70 (macrophage cytokines), interferon‐γ (IFN‐γ) (Th1 cytokine), IL‐4 (Th2 cytokine) and circulating CD4⁺ CD25^highFoxP3⁺ T‐regs, in untreated leprosy patients. Forty three patients and 40 controls were assessed for the mentioned cytokines using ELISA. Patients were assessed for circulating T‐regs using flow cytometry. Patients were subgrouped into tuberculoid (TT), pure neural leprosy (PNL), borderline cases, lepromatous (LL), type 1 reactional leprosy (RL1) and erythema nodosum leprosum (ENL). Serum IL‐12p70, IFN‐γ and IL‐4 were significantly higher in patients versus controls (P < 0.05). Serum IL‐4 was highest in LL and lowest in RL1 (P = 0.003). Serum IL‐1β levels was significantly higher in multibacillary versus paucibacillary patients (P = 0.006). Significantly higher T‐regs levels was detected in TT, RL1 and PNL, while the lowest levels in ENL(P < 0.001), with significant differences versus controls (P < 0.05). FoxP3 expression% was significantly lower in PNL than other patients and controls (P < 0.05). T‐regs/T‐effs was lowest in ENL(P < 0.05). IFN‐γ correlated positively with T‐regs but negatively with IL‐1β (P = 0.041&0.046 respectively), which correlated positively with T‐effs%( P = 0.05). IL‐4 correlated positively with T‐regs FoxP3 expression% (P = 0.009). We concluded that: Circulating T‐regs were increased in TT, RL1 and PNL patients, known of relatively high cell‐mediated immunity. This finding was supported by low FoxP3 expression (in PNL) and correlation between T‐regs count and IFN‐γ level. Overproduction of IL‐4 in LL may infer liability to develop ENL, with disease progression and immune hyperactivation, marked by deficient T‐regs and increased T‐regs FoxP3 expression%. IL‐1β probably has a pro‐inflammatory role in multibacillary patients as correlated with T‐effs%.     

Mechanism of pathogenesis of imiquimod‐induced skin inflammation in the mouse: A role for interferon‐alpha in dendritic cell activation by imiquimod

Topical application of imiquimod (IMQ), a Toll‐like receptor (TLR)7 ligand, can induce and exacerbate psoriasis, a chronic inflammatory skin disorder. In a mouse model of IMQ‐induced psoriasis‐like skin inflammation, T‐helper (Th)17 cells and interleukin (IL)‐17/IL‐22‐producing γδ‐T cells have been shown to play a pivotal role. However, the mechanisms of induction of the Th17 pathway and development of psoriasis‐like skin inflammation by IMQ treatment remain unclear. In this study, we investigated pathogenic mechanisms of IMQ‐induced psoriasis‐like skin inflammation in mice. We first confirmed that, together with an increase in IL‐17 and IL‐22 production, application of IMQ to mouse skin induced the expression of cytokines required for activation of the Th17 pathway, and pro‐inflammatory mediators involved in the pathology of psoriasis. Analysis of Tlr7^?/? mice demonstrated that most of the in vivo effects of IMQ were mediated via TLR7. In an in vitro study using plasmacytoid dendritic cells (DCs), IMQ induced production of interferon (IFN)‐α, IL‐23, IL‐6 and tumor necrosis factor (TNF)‐α. Furthermore, when we analyzed in vitro‐generated bone marrow‐derived DCs with features similar to TNF‐α and inducible nitric oxide synthase (iNOS)‐producing DCs, IL‐23, IL‐6, IL‐1β, TNF‐α and iNOS/NO production was weakly induced by IMQ alone and further enhanced after co‐stimulation with IMQ and IFN‐α. These in vitro effects of IMQ were also mediated via TLR7 and the synergistic effect of IMQ, and IFN‐α was suggested to be caused by upregulation of TLR7 expression by IFN‐α. These results demonstrate part of the mechanism by which the Th17 pathway and psoriasis‐like skin inflammation are induced by IMQ and IFN‐α in a mouse model.     

Insufficient generation of Th17 cells in IL‐23p19‐deficient BALB/c mice protects against progressive cutaneous leishmaniasis

Healing of leishmaniasis—a parasitic skin disease—is associated with high levels of secreted interferon (IFN)γ and IL‐12 in resistant C57BL/6 mice and humans. Susceptible BALB/c mice predominantly react with a Th17/Th2/Treg‐related immune response and finally succumb to infection. Previously, we showed that BALB/c IL‐17A^?/? mice are protected against Leishmania (L.) major infections, indicating that IL‐17A—predominantly produced by Th17 cells—plays an important role for disease outcome. We now investigated DC‐derived cytokines and finally identified IL‐23p19 as key cytokine responsible for induction of Leishmania‐specific Th17 cells that play an important role for progressive disease in susceptible BALB/c mice.     

Propionibacterium acnes vaccination induces regulatory T cells and Th1 immune responses and improves mouse atopic dermatitis

Abstract: Atopic dermatitis (AD) is a chronic disease characterized by a polarized Th2 immune response. Propionibacterium acnes (P. acnes) has been shown to elicit strong Th1 immune responses. We hypothesized that the host immune response to P. acnes will prevent the development of AD. To demonstrate this hypothesis, we investigated the effect of P. acnes vaccination on AD that occurs in keratin 14/driven caspase‐1 transgenic mouse. Vaccination with low dose of P. acnes successfully prevented clinical manifestations in the skin of AD mice associated with systemic and cutaneous increased expression of Th1‐type cytokines but without suppression of Th2 cytokines. Interestingly, the numbers of IFN‐γ⁺T cells, FoxP3⁺CD4⁺CD25⁺T cells (nTreg) and IL‐10⁺T cells (Tr1) were significantly increased in the spleen. P. acnes vaccination has effects to alter the cytokine milieu and may be useful for the improvement of atopic symptom.     

IL‐1 signalling determines the fate of skin grafts expressing non‐self protein in keratinocytes

Please cite this paper as: IL‐1 signalling determines the fate of skin grafts expressing non‐self protein in keratinocytes. Experimental Dermatology 2010; 19 : 723–729. Abstract: Although IL‐1 is a known inflammatory cytokine during pathogen infection, the role of IL‐1 in skin graft rejection, particularly where foreign antigen is expressed exclusively in keratinocytes, is less understood. Here, we use a syngeneic skin graft system, where antigens are expressed in epithelial cells via either a keratin 14 or keratin 5 promoter, to explore the role of IL‐1 in graft rejection and induction of epithelial antigen‐specific effector CD8⁺ T‐cell function. Keratin 5 ovalbumin (K5mOVA) transgenic skin grafts destined for rejection demonstrated increased expression of IL‐1β and its receptors compared to K14 HPV16 E7 transgenic grafts that do not reject spontaneously. Rejection of OVA grafts lacking the IL‐1 receptor (IL‐1R1) was delayed and associated with decreased numbers of antigen‐specific CD8 T cells. In contrast, K14E7 grafts survived on immunocompetent, syngeneic recipients with decreased graft levels of IL‐1β and IL‐1R1 and 2. However, in the absence of the IL‐1 receptor antagonist, IL‐1Ra, skin grafts were spontaneously rejected and an E7‐specific CD8 T‐cell response was primed. Thus, expression of the HPV16E7 oncoprotein in epithelial cells prevents IL‐1β‐associated skin graft rejection and induction of antigen‐specific CD8 T‐cell responses. Enhancing IL‐1β signalling, via blocking of the IL‐1 receptor antagonist, may represent an alternative strategy for treatment of HPV16E7‐associated cancers.     

Oligosaccharide modification by N‐acetylglucosaminyltransferase‐V in macrophages are involved in pathogenesis of bleomycin‐induced scleroderma

Oligosaccharide modification by N‐acetylglucosaminyltransferase‐V (GnT‐V), which catalyses the formation of β1,6 GlcNAc (N‐acetylglucosamine) branches on N‐glycans, is associated with various pathologies, such as cancer metastasis, multiple sclerosis and liver fibrosis. In this study, we demonstrated the involvement of GnT‐V in the pathophysiology of scleroderma. High expression of GnT‐V was observed in infiltrating cells in skin section samples from systemic and localized patients with scleroderma. Most of the infiltrating cells were T cells and macrophages, most of which were CD163⁺ M2 macrophages. To determine the role of GnT‐V in scleroderma, we next investigated skin sclerosis in GnT‐V knockout (MGAT5^?/?) mice. Expression of GnT‐V was also elevated in bleomycin (BLM)‐injected sclerotic skin, and MGAT5^?/? mice were resistant to BLM‐induced skin sclerosis with reduced collagen type 1 α1 content, suggesting the biological significance of GnT‐V in skin sclerosis. Furthermore, the number of CD163⁺ M2 macrophages and CD3‐positive T cells in BLM‐induced skin sclerosis was significantly fewer in MGAT5^?/? mice. In bone marrow‐derived macrophages (BMDMs), IL‐4‐induced expressions of Fizz1 and Ym1 were significantly reduced in MGAT5^?/? mice‐derived BMDMs. Taken together, these results suggest the induction of GnT‐V in skin sclerosis progression is possibly dependent on increased numbers of M2 macrophages in the skin, which are important for tissue fibrosis and remodelling.     

Analysis of serum chemokine levels in patients with HIV‐associated eosinophilic folliculitis

Background Patients with human immunodeficiency virus (HIV) infection exhibit various skin diseases. HIV‐associated eosinophilic folliculitis (EF) and pruritic papular eruption (PPE) are frequently seen. Objective To understand the mechanisms underlying HIV‐associated EF and PPE. Methods In order to know frequencies of EF and PPE among patients with HIV infection, we first collected HIV⁺ patients who visited dermatology clinic in National Center for Global Health and Medicine during February 2007. We next collected 25 serum samples from HIV⁺ patients with skin diseases from May 2008 to May 2010. Eight of 25 patients had EF (EF group), four had PPE (PPE group) and others had non‐itchy skin problems such as condyloma acuminatum (no itch group). Results We first confirmed high frequencies of EF (10.7%) and PPE (5.3%) among 75 HIV⁺ patients who visited our clinic during one month. We then measured serum levels of CCL11, CCL17, CCL26 and CCL27. Serum CCL17 levels in EF were significantly higher than those of PPE and no itch group. Serum CCL26 and CCL27 levels in EF were higher than those of no itch group. The number of CD4⁺ cells in EF was significantly lower than that in no itch group. Conclusion High serum levels of CCL17, CCL26 and CCL27, and low CD4⁺ cell counts may account for the development of HIV‐associated EF.     

Oral vitamin D increases the frequencies of CD38+ human B cells and ameliorates IL‐17‐producing T cells

Vitamin D deficiency (serum 25‐hydroxyvitamin D < 50 nm ) has been associated with the onset of immunological diseases including atopic dermatitis (AD), cutaneous or systemic lupus erythematosus and allergic asthma. In this study, we assessed whether oral vitamin D (cholecalciferol) supplementation leads to a systemic modulation of the phenotype of circulating lymphocyte populations and whether a defined serum 25‐hydroxyvitamin D (25(OH)D) concentration can be related to the effects on lymphocytes. Cholecalciferol was administered in a dose‐escalation setting to vitamin D–deficient individuals from 2000 up to 8000 IU daily for 12 weeks. Individuals without cholecalciferol intake served as controls. Peripheral B cells and T cells were examined by multicolour flow cytometric analysis. The mean serum 25(OH)D concentrations increased upon cholecalciferol intake up to 159 ± 28.7 nm , and remained low in the control group 30.0 ± 12.5 nm . Following cholecalciferol intake, the frequencies of circulating CD38 expressing B cells were significantly increased and IFN‐γ⁺, and/or IL‐17⁺ CD4⁺ T helper cells were decreased. These data were identified to correlate with the serum 25(OH)D levels by applying two different analysis approaches (ROC and a nonlinear regression analysis). Our data indicate that increasing 25(OH)D serum concentrations are associated with an increased expression of CD38 on B cells and a decreased T‐cell‐dependent proinflammatory cytokine production. The therapeutical role of our findings in systemic immunological diseases should be explored in the future by further controlled clinical studies.     

Characterization of the T cell response in allergic contact dermatitis caused by corticosteroids

Background Delayed allergic hypersensitivity reactions have classically been described as type IV reactions, which are caused by T cells; however, the respective roles of CD4⁺ and CD8⁺ cells are yet to be defined. A central role for CD8⁺ cytotoxic T cells as effector cells has been suggested. Objectives To determine the type of T cell involved in corticosteroid allergy. Methods We analysed the kinetics of T cell recruitment and the cytokine production profile in positive patch tests of 27 corticosteroid‐sensitized patients, as compared with control sites and control subjects. Skin biopsies, collected at 8, 24 and 48 hr following drug application, were embedded in paraffin for histological and immunohistological staining, and, in some cases, also deep‐frozen for gene expression analyses. Results CD3⁺ T cells were rapidly recruited in concert with the positivity of the patch test sites. High levels of interleukin (IL)‐4, IL‐5 and, to a lesser extent, interferon‐γ suggested that both Th2 and Th1 cytokines were implicated. IL‐4 was also produced by γδ T cell receptor (TCR) lymphocytes. Conclusions This study showed that, in allergic contact dermatitis caused by corticosteroids, the inflammatory infiltrate is composed of CD3⁺ T cells with a predominant Th2 cytokine profile, among which IL‐4 is also produced by γδ TCR lymphocytes.     

Expression analysis of PD‐1 and Tim‐3 immune checkpoint receptors in patients with vitiligo; positive association with disease activity

The contribution of immune checkpoint receptors in the immunopathogenesis of various autoimmune diseases has been addressed in previous reports. In this study,  the expression profile of T‐cell immunoglobulin and mucin‐domain containing‐3 (Tim‐3) and programmed cell death‐1 (PD‐1) checkpoint molecules was investigated in CD8⁺ T cells of Vitiligo patients. The association of Tim‐3 and PD‐1 expression with disease activity was also explored. The frequency of Tim‐3⁺/PD‐1⁺/CD8⁺ T cells in 30 patients with vitiligo and 30 sex‐ and age‐matched controls was determined by flow cytometry. CD8⁺ T cells were then positively isolated by magnetic beads, and the mRNA expression of PD‐1 and Tim‐3 was determined by TaqMan‐based real‐time PCR. To measure the cytokines production, PBMCs were stimulated with PMA/ionomycin and concentrations of IL‐4, IFN‐γ and TNF‐α were measured in culture supernatants by ELISA. Disease activity of patients with vitiligo was determined using the Vitiligo Area Severity Index. Patients with vitiligo have significantly shown more expression of Tim‐3 and PD‐1 on their CD8⁺ T cells compared with controls. Expression analysis of Tim‐3 mRNA, but not PD‐1, confirmed the results obtained from flow cytometry. While the production levels of TNF‐α and IFN‐γ were found higher by patients with vitiligo, IL‐4 production was lower in patients compared with controls. A direct association was observed between the Tim‐3 and PD‐1 expression and also the production of pro‐inflammatory cytokines with disease activity of patients with vitiligo. Our results indicate that Tim‐3 and PD‐1 are involved in immune dysregulation mechanisms of CD8⁺ T cells in vitiligo and may introduce as potential biomarkers for disease progression and targeted immunotherapy.     

Interleukin‐21 receptor signalling is not critically required for imiquimod‐induced psoriasiform dermatitis in mice

Psoriasis is largely mediated by interleukin (IL)‐23/T helper (Th) 17 axis, and IL‐21 is a pleiotropic cytokine expressed by Th17 cells. Despite previously reported possible pathogenic roles of IL‐21 in human psoriasis, we found that IL‐21 receptor (IL‐21R) signalling was not crucial for imiquimod‐induced psoriatic inflammation, using IL‐21R^?/? mice. The severity of imiquimod‐induced psoriatic manifestation and pro‐inflammatory Th17 cytokine levels, IL‐17A‐producing γδ T cells and CD4+ T cells, and in vitro IL‐17A production by γδ T cells after IL‐23 stimulation was comparable between wild‐type and IL‐21R^?/? mice. Collectively, IL‐21R signalling was not critically involved in IMQ‐induced psoriatic inflammation despite an increased IL‐21 expression in the IMQ‐treated mouse skin. Our data may represent the significant differences between human psoriasis and murine psoriasis model, and further studies using other models will be required to elucidate the role of IL‐21 in psoriasis pathogenesis.     

Papuloerythroderma‐like cutaneous involvement of a CD62L− subclone of T‐cell prolymphocytic leukemia

We report the case of an 88‐year‐old Japanese man with erythrodermic involvement of T‐cell prolymphocytic leukemia (T‐PLL). He had a history of pharyngeal diffuse large B‐cell lymphoma successfully treated with polychemotherapy including cyclophosphamide and epirubicin, 6 years before the current illness. He presented with numerous reddish, coalescing, flat‐topped papules on the trunk and extremities, sparing the skin folds of the abdomen, the features of which mimicked those of papuloerythroderma. Immunohistochemistry showed perivascular and epidermotropic infiltration of CD3⁺ CD4⁺ T cells in the cutaneous lesion. However, flow cytometric analysis revealed that the skin infiltrating T cells were negative for surface CD4, and that CD3⁺ CD4^? CD8^? cells made up 92% of the T‐cell fraction of peripheral blood. The circulating atypical T cells had a round or oval nucleus and prominent nucleoli, and the deletion of chromosomes 6q, 13 and 17. These cytological profiles were consistent with those of T‐PLL and distinct from those of Sézary cells. The same T‐cell clone was detected in the cutaneous lesion and peripheral blood, but the expression of CD62L was absent in the skin infiltrates and present in the circulating cells. No specific mutation was detected in STAT3 or STAT5B. Although low‐dose oral etoposide had a beneficial effect on the skin rash, a fatal crisis of marked leukocytosis (169 × 10³/μL) occurred 19 months after the illness onset. CD62L‐leukemic cells of T‐PLL may infiltrate the skin to form papuloerythroderma‐like cutaneous lesions.     

Osteopontin deficiency affects imiquimod‐induced psoriasis‐like murine skin inflammation and lymphocyte distribution in skin,draining lymph nodes and spleen

Osteopontin (OPN) that enhances autoimmunity is expressed in psoriasis lesions; however, its functions in psoriatic inflammation are unknown. We investigated the role of OPN in OPN deficient mice (OPN?/?) by inducing psoriasis‐like inflammation through skin application of imiquimod (IMQ). OPN?/? mice treated with IMQ showed delayed onset ear swelling and attracted less inflammatory cells to the skin. IMQ‐induced lymph node swelling was reduced in the absence of OPN, and IMQ‐mediated expansion of B cells was inhibited. Further, reduction of CD4⁺ T‐cell numbers by IMQ in lymph nodes was suppressed in OPN?/? mice, with an increase in the CD4/CD8 ratio. A comparable pattern was found in spleen. Importantly, IMQ‐induced IL‐17 and IL‐4 expression by CD4⁺ lymph node T cells was reduced in OPN?/? mice. In conclusion, OPN may modulate psoriasis‐like inflammation through altering lymphocyte distribution in skin and draining lymph nodes and by inducing IL‐17 expression of inflammatory T cells.     

Acitretin exerted a greater influence on T‐helper (Th)1 and Th17 than on Th2 cells in treatment of psoriasis vulgaris

T‐helper (Th) cells, including Th1, Th2 and Th17 cells, may play an important role in the pathogenesis of psoriasis vulgaris (PV). Acitretin is an effective treatment for PV; however, its influence on Th cells during the treatment of PV is unclear. This study aimed to investigate the influence of acitretin on Th1, Th2 and Th17 cells in PV patients. PV patients (n = 30) received acitretin p.o. (20 mg/day) for 8 weeks. Sera and skin biopsies were obtained before and after treatment. Double‐labeled immunofluorescence was used to analyze T, Th1, Th2 and Th17 cells in skin lesions. Enzyme‐linked immunosorbent assay and western blot were used to analyze the expressions of interferon (IFN)‐γ, interleukin (IL)‐4 and IL‐17 in sera and skin lesions. The expressions of IFN‐γ mRNA, IL‐4 mRNA and IL‐17 mRNA in skin lesions were detected by in situ hybridization. Acitretin decreased the quantity of T, Th1 and Th17 cells in PV lesions, but had no significant influence on Th2 cells. Acitretin also decreased the expression of IFN‐γ and IL‐17 in serum and lesions. The expressions of IFN‐γ mRNA and IL‐17 mRNA decreased significantly after 8 weeks of therapy. However, acitretin had no significant influence on the expression of IL‐4 protein and mRNA. Acitretin can reverse Th1 and Th17 preponderance in PV patients to some degree. This may be due to the mechanism of acitretin on PV; however, Th2 cells were not affected by acitretin treatment.     

Role of the subgroups of T,B, natural killer lymphocyte and serum levels of interleukin‐15, interleukin‐21 and immunoglobulin E in the pathogenesis of urticaria

The immunological characterization in the pathogenesis of urticaria, mainly regarding cytokine profile, needs more investigation. In this study, subgroups of the T, B and natural killer (NK) lymphocyte from peripheral blood and serum levels of interleukin (IL)‐15, IL‐21 and immunoglobulin (Ig)E were examined in patients with acute urticaria (AU) and chronic urticaria (CU). Moreover, symptom scores and course of the patients were assessed. The percentage of NK cells and the ratio of CD4⁺/CD8⁺ increased, however, CD8⁺ decreased in CU compared to controls (P < 0.01). But no significant changes of T, B and NK lymphocyte were found in AU. IL‐15 and IL‐21 significantly decreased in AU and CU, but IgE increased. CU with a positive autologous serum skin test were more likely to be associated with longer course and higher CD3⁺, B cells and IL‐21, and lower IgE (P < 0.01). Weak negative correlations were demonstrated between CD3⁺, CD8⁺ and scores in CU (r = ?0.23, ?0.25, P < 0.05). Significant correlations were found between B cells and scores and course in CU (r = 0.49, 0.65, P < 0.01). Moreover, a significant correlation was found between IL‐21 and IgE (r = 0.42, P < 0.01) in CU. But no significant correlations were found in AU. Our findings supported the concept that both humoral immunity and cellular immunity dysregulation in the pathogenesis of urticaria – mainly related to the decrease of the serum levels of IL‐15 and IL‐21 – may induce the increasing expression of IgE produced by B cells.     

Coexpression of CCR6 and CD146 (MCAM) is a marker of effector memory T-helper 17 cells

Effector memory T (T_EM) cells are a subpopulation of memory T cells that express receptors mediating migration to inflamed tissues and produce various cytokines. Effector memory T‐helper (Th)17 (Th17_EM) cells are thought to be essential for inflammation in Th17‐mediated diseases, but have not been studied in detail. To identify superior surface markers to isolate a homogeneous population of Th17_EM cells from peripheral blood, CD4⁺ T cells were isolated from the peripheral blood of healthy donors based on the expression of CCR7, CCR6 and CD146 using six‐color flow cytometry. After 4 days of culture in the presence of anti‐CD3/28 beads, intracellular cytokines were determined by flow cytometric analysis. To investigate the relevance of Th17_EM cells in Th17‐mediated disease, the frequencies of T_EM‐cell subsets in psoriasis were quantified using six‐color flow cytometry. An enzyme‐linked immunosorbent assay was performed to confirm the interleukin (IL)‐17‐producing capacity of T_EM‐cell subsets from the peripheral blood of a patient with psoriasis. CCR6⁺CD146⁺ T_EM (CD4⁺CD45RA^?CCR7^?) cells had a greater capacity to produce IL‐17 than CCR6⁺CD146^? or CCR6^?CD146⁺ T_EM cells. Although the percentage of CCR6⁺CD146⁺ cells in T_EM cells was not significantly different between patients with psoriasis and controls, three of eight patients had a higher percentage of CCR6⁺CD146⁺ T_EM cells than the mean +5 standard deviations of the controls. Coexpression of CCR6 and CD146 is a useful marker for Th17_EM cells. Increasing the number of CCR6⁺CD146⁺ Th17_EM cells in peripheral blood may facilitate estimation of systemic Th17‐cell activity in Th17‐mediated diseases.