Correlations between disease activity, autoimmunity and biological parameters in patients with chronic spontaneous urticaria.

Summary: Background. Biomarkers of disease activity/severity and criteria of autoimmune chronic spontaneous urticaria (CSU) are still a matter of debate. Objective. To investigate possible correlations between clinical and biological markers and their associations with: 1) disease activity, 2) resistance to H1-antihistamines, 3) autoimmunity and 4) autologous serum skin test (ASST) in patients with CSU. To also analyze biological parameter modifications in patients with CSU treated with omalizumab. Materials and methods. Disease activity, H1-antihistamines response and presence of concomitant autoimmune disease were prospectively recorded in 95 patients with CSU. For 60 of them, ASST was performed. Broad biological analysis were performed. Results. C-reactive protein (CRP) serum levels were higher in H1-antihistamines unresponders (p less-than 0.0001) and in more active diseases (p = 0.033). D-dimer plasma levels were higher in H1-antihistamines unresponders (p = 0.008) and in patients with autoimmune status (concomitant autoimmune disease and/or with autoantibodies) (p = 0.016). Total immunoglobuline E (IgE) serum level was lower in patients with positive ASST. Blood basophil counts were lower in patients with CSU and especially in H1-antihistamines unresponders (p = 0.023), in patients with more active disease (p = 0.023), with positive ASST (p = 0.001), and with autoimmune status (p = 0.057). Conversely, under omalizumab, a decrease of CRP (p = 0.0038) and D-dimer serum/plasma levels (p = 0.0002) and an increase of blood basophil counts (p = 0.0023) and total IgE serum levels (p = 0.0007) were observed. Conclusions. This study brings additional evidences of interest to investigate IgE, D-dimer serum/plasma levels and basophil blood counts in patients with CSU as they could be correlated to disease activity, response to treatment and/or autoimmunity.

Improvement of psoriasis during glucagon-like peptide-1 analogue therapy in type 2 diabetes is associated with decreasing dermal γδ T-cell number: a prospective case-series study.

BACKGROUND: A few case reports suggest that incretin-based therapies could improve psoriasis in patients with type 2 diabetes, the mechanism(s) of which remain unclear. OBJECTIVES: To determine the effects after 16-20 weeks of treatment with a glucagon-like peptide (GLP)-1 analogue on clinical severity and histopathological aspects of psoriasis in patients with type 2 diabetes, and to examine the presence of γδ T cells and the expression of interleukin (IL)-17 in psoriasis before and after treatment. METHODS: Seven patients with type 2 diabetes and psoriasis were followed. Psoriasis Area and Severity Index (PASI) was measured at baseline (T0) and after 7 ± 1 (T1) and 18 ± 2 (T2) weeks' treatment with exenatide/liraglutide. The histopathological pattern of psoriasis, and flow cytometry and immunological data (γδ T-cell percentage and IL-17 expression) were obtained from psoriatic and control sites. RESULTS: The mean PASI decreased from 12·0 ± 5·9 to 9·2 ± 6·4 (P = 0·04). Histological analysis showed a reduction in epidermal thickness after treatment. The dermal γδ T-cell percentage was higher in psoriatic lesions than in control specimens (P = 0·03), as was IL-17 expression (P = 0·018). A reduction of γδ T cells from 6·7 ± 4·5% to 2·7 ± 3·8% (P = 0·05) was demonstrated in the six patients with improved/unchanged PASI. A correlation between PASI and γδ T-cell percentage evolution during therapy (T2-T0) was noted (r = 0·894, P = 0·007). IL-17 was reduced in the four patients with the highest PASI reductions. CONCLUSIONS: The administration of a GLP-1 analogue improved clinical psoriasis severity in patients with type 2 diabetes. This favourable outcome was associated with a decrease of dermal γδ T-cell number and IL-17 expression. Further studies are needed to establish long-term efficacy in (diabetic) patients with psoriasis.

Correction: Interleukin-22-deficiency and microbiota contribute to the exacerbation of Toxoplasma gondii-induced intestinal inflammation.

The original version of this Article omitted the author Dr Mathias Chamaillard from the l'Institut de Pasteur, Lille, France. This has been corrected in both the PDF and HTML versions of the Article.

Interleukin-22 deficiency accelerates the rejection of full major histocompatibility complex-disparate heart allografts.

Interleukin-22 (IL-22) was recently described as an effector cytokine produced by TH17 CD4(+) T lymphocytes that, cooperatively with IL-17, mediates IL-23-driven inflammation. Because there was experimental evidence for the role of IL-17 in acute rejection of vascularized allografts, we undertook the present study to assess the function of IL-22 in the process. There was an early transient expression of IL-22 in C57BL/6 mouse cardiac allografts (2-4 days posttransplantation) transplanted to BALB/c recipients. The main source of IL-22 among infiltrating leukocytes was cells expressing the macrophage/monocyte markers Mac3 and CD11b. T cells and granulocytes present in the rejected graft did not express IL-22. Surprisingly, the absence of IL-22 accelerated the rejection of fully histoincompatible hearts. Histology of rejected organs revealed the presence of intensive intragraft thrombosis and disseminated hemorrhagic necrosis. Taken together, these results demonstrated that IL-22 was not an effector lymphokine in cardiac allograft rejection, but early intragraft expression of the cytokine protected it from rejection.

Interleukin-22-deficiency and microbiota contribute to the exacerbation of Toxoplasma gondii-induced intestinal inflammation.

Upon oral infection with Toxoplasma gondii cysts (76 K strain) tachyzoites are released into the intestinal lumen and cross the epithelial barrier causing damage and acute intestinal inflammation in C57BL/6 (B6) mice. Here we investigated the role of microbiota and IL-22 in T.gondii-induced small intestinal inflammation. Oral T.gondii infection in B6 mice causes inflammation with IFNγ and IL-22 production. In IL-22-deficient mice, T.gondii infection augments the Th1 driven inflammation. Deficiency in either IL-22bp, the soluble IL-22 receptor or Reg3γ, an IL-22-dependent antimicrobial lectin/peptide, did not reduce inflammation. Under germ-free conditions, T.gondii-induced inflammation was reduced in correlation with parasite load. But intestinal inflammation is still present in germ-free mice, at low level, in the lamina propria, independently of IL-22 expression. Exacerbated intestinal inflammation driven by absence of IL-22 appears to be independent of IL-22 deficiency associated-dysbiosis as similar inflammation was observed after fecal transplantation of IL-22-/- or WT microbiota to germ-free-WT mice. Our results suggest cooperation between parasite and intestinal microbiota in small intestine inflammation development and endogenous IL-22 seems to exert a protective role independently of its effect on the microbiota. In conclusion, IL-22 participates in T.gondii induced acute small intestinal inflammation independently of microbiota and Reg3γ.

Bcl-3 expression promotes cell survival following interleukin-4 deprivation and is controlled by AP1 and AP1-like transcription factors.

We have analyzed the interleukin-4 (IL-4)-triggered mechanisms implicated in cell survival and show here that IL-4 deprivation induces apoptotic cell death but does not modulate Bcl-2 or Bcl-x expression. Since Bcl-x expression is insufficient to ensure cell survival in the absence of IL-4, we speculate that additional molecules replace the antiapoptotic role of Bcl-2 and Bcl-x in an alternative IL-4-triggered pathway. Cell death is associated with Bcl-3 downregulation and Bcl-3 expression blocks IL-4 deprivation-induced apoptosis, suggesting that Bcl-3 acts as a survival factor in the absence of growth factor. To characterize the IL-4-induced regulation of murine Bcl-3 expression, we cloned the promoter of this gene. Sequencing of the promoter showed no TATA box element but did reveal binding sites for AP1, AP1-like, and SP1 transcription factors. Retardation gels showed that IL-4 specifically induces AP1 and AP1-like binding activity and that mutation of these binding sites abolishes the IL-4-induced Bcl-3 promoter activity, suggesting that these transcription factors are important in Bcl-3 promoter transactivation. IL-4 deprivation induces downregulation of Jun expression and upregulation of Fos expression, both of which are proteins involved in the formation of AP1 and AP1-like transcription factors. Overexpression of Jun family proteins transactivates the promoter and restores Bcl-3 expression in the absence of IL-4 stimulation. Taken together, these data describe a new biological role for Bcl-3 and define the regulatory pathway implicated in Bcl-3 expression.

Interleukin-9 induces 24P3 lipocalin gene expression in murine T cell lymphomas.

Interleukin-9 (IL-9) is a Th2 cytokine whose overexpression is associated with asthma and T cell lymphomagenesis. All the IL-9 activities studied so far are mediated by a specific hemopoietin receptor that activates a Jak/STAT pathway. Searching for genes specifically modulated by IL-9, we observed that the 24P3 mRNA is strongly upregulated in BW5147 T lymphoma cells upon IL-9 stimulation. 24P3 is a member of the lipocalin family, and has been reported to bind N-formyl-Met-Leu-Phe, a potent neutrophil chemoattractant, and possibly other lipophilic mediators of inflammation. A similar 24P3 induction was observed in other T cell lymphomas (EL4 and TH201) in response to IL-9, as well as in EL4 cells stimulated with IL-6 or IL-1. By contrast, other IL-9-responsive cells such as mast cell line MC9 and B cell lymphoma A20 showed no 24P3 induction upon IL-9 stimulation. Experiments using IL-9R mutants indicated that STAT transcription factors, particularly STAT3, are involved in this process. However, 24P3 gene induction was slow, reaching a plateau from 36 to 72 hours after stimulation and was inhibited if cells were treated with cycloheximide during the first 8 hours of IL-9 stimulation, suggesting an indirect induction requiring new protein synthesis.

Cloning and characterization of IL-10-related T cell-derived inducible factor (IL-TIF), a novel cytokine structurally related to IL-10 and inducible by IL-9.

IL-9 is a Th2 cytokine active on various cell types such as T and B lymphocytes, mast cells, and eosinophils, and potentially involved in allergy and asthma. To understand better the molecular mechanisms underlying the activity of this cytokine, we used a cDNA subtraction method to identify genes specifically induced by IL-9 in mouse T cells. One of the IL-9-regulated genes isolated by this approach turned out to encode a 180-amino acid long protein, including a potential signal peptide, and showing 22% amino acid identity with IL-10. This protein, designated IL-10-related T cell-derived inducible factor (IL-TIF), is induced by IL-9 in thymic lymphomas, T cells, and mast cells, and by lectins in freshly isolated splenocytes. Experiments concerning the mechanism regulating IL-TIF expression in T cells indicate that IL-9 induction is rapid (within 1 h), does not require protein synthesis, and depends on the activation of the Janus kinase (JAK)-STAT pathway. In vivo, constitutive expression of IL-TIF was detected by RT-PCR in thymus and brain, suggesting that the role of this new factor is not restricted to the immune system. Transfection of HEK293 cells with the IL-TIF cDNA resulted in the production of a glycosylated protein of about 25 kDa that was found to induce STAT activation in mesangial and neuronal cell lines. Further studies will have to address the possibility that some of the IL-9 activities may be mediated by IL-TIF.

Cloning and characterization of IL-22 binding protein, a natural antagonist of IL-10-related T cell-derived inducible factor/IL-22.

The class II cytokine receptor family includes the receptors for IFN-alphabeta, IFN-gamma, IL-10, and IL-10-related T cell-derived inducible factor/IL-22. By screening genomic DNA databases, we identified a gene encoding a protein of 231 aa, showing 33 and 34% amino acid identity with the extracellular domains of the IL-22 receptor and of the IL-20R/cytokine receptor family 2-8, respectively, but lacking the transmembrane and cytoplasmic domains. A lower but significant sequence identity was found with other members of this family such as the IL-10R (29%), cytokine receptor family 2-4/IL-10Rbeta (30%), tissue factor (26%), and the four IFN receptor chains (23-25%). This gene is located on chromosome 6q24, at 35 kb from the IFNGR1 gene, and is expressed in various tissues with maximal expression in breast, lungs, and colon. The recombinant protein was found to bind IL-10-related T cell-derived inducible factor/IL-22, and to inhibit the activity of this cytokine on hepatocytes and intestinal epithelial cells. We propose to name this natural cytokine antagonist IL-22BP for IL-22 binding protein.

Human interleukin-10-related T cell-derived inducible factor: molecular cloning and functional characterization as an hepatocyte-stimulating factor.

IL-10-related T cell-derived inducible factor (IL-TIF or IL-21) is a new cytokine structurally related to IL-10 and originally identified in the mouse as a gene induced by IL-9 in T cells and mast cells. Here, we report the cloning of the human IL-TIF cDNA, which shares 79% amino acid identity with mouse IL-TIF and 25% identity with human IL-10. Recombinant human IL-TIF was found to activate signal transducer and activator of transcription factors-1 and -3 in several hepatoma cell lines. IL-TIF stimulation of HepG2 human hepatoma cells up-regulated the production of acute phase reactants such as serum amyloid A, alpha1-antichymotrypsin, and haptoglobin. Although IL-10 and IL-TIF have distinct activities, antibodies directed against the beta chain of the IL-10 receptor blocked the induction of acute phase reactants by IL-TIF, indicating that this chain is a common component of the IL-10 and IL-TIF receptors. Similar acute phase reactant induction was observed in mouse liver upon IL-TIF injection, and IL-TIF expression was found to be rapidly increased after lipopolysaccharide (LPS) injection, suggesting that this cytokine contributes to the inflammatory response in vivo.

IL-TIF/IL-22: genomic organization and mapping of the human and mouse genes.

IL-TIF is a new cytokine originally identified as a gene induced by IL-9 in murine T lymphocytes, and showing 22% amino acid identity with IL-10. Here, we report the sequence and organization of the mouse and human IL-TIF genes, which both consist of 6 exons spreading over approximately 6 Kb. The IL-TIF gene is a single copy gene in humans, and is located on chromosome 12q15, at 90 Kb from the IFN gamma gene, and at 27 Kb from the AK155 gene, which codes for another IL-10-related cytokine. In the mouse, the IL-TIF gene is located on chromosome 10, also in the same region as the IFN gamma gene. Although it is a single copy gene in BALB/c and DBA/2 mice, the IL-TIF gene is duplicated in other strains such as C57Bl/6, FVB and 129. The two copies, which show 98% nucleotide identity in the coding region, were named IL-TIF alpha and IL-TIF beta. Beside single nucleotide variations, they differ by a 658 nucleotide deletion in IL-TIF beta, including the first non-coding exon and 603 nucleotides from the promoter. A DNA fragment corresponding to this deletion was sufficient to confer IL-9-regulated expression of a luciferase reporter plasmid, suggesting that the IL-TIF beta gene is either differentially regulated, or not expressed at all.

Cutting edge: STAT activation by IL-19, IL-20 and mda-7 through IL-20 receptor complexes of two types.

IL-10-related cytokines include IL-20 and IL-22, which induce, respectively, keratinocyte proliferation and acute phase production by hepatocytes, as well as IL-19, melanoma differentiation-associated gene 7, and AK155, three cytokines for which no activity nor receptor complex has been described thus far. Here, we show that mda-7 and IL-19 bind to the previously described IL-20R complex, composed by cytokine receptor family 2-8/IL-20Ralpha and DIRS1/IL-20Rbeta (type I IL-20R). In addition, mda-7 and IL-20, but not IL-19, bind to another receptor complex, composed by IL-22R and DIRS1/IL20Rbeta (type II IL-20R). In both cases, binding of the ligands results in STAT3 phosphorylation and activation of a minimal promoter including STAT-binding sites. Taken together, these results demonstrate that: 1) IL-20 induces STAT activation through IL-20R complexes of two types; 2) mda-7 and IL-20 redundantly signal through both complexes; and 3) IL-19 signals only through the type I IL-20R complex.

Crystallization and synchrotron X-ray diffraction studies of human interleukin-22.

Human interleukin-22, a novel member of the cytokine family, has been crystallized in hanging drops using the vapour-diffusion technique. Preliminary X-ray diffraction experiments using synchrotron radiation reveal that the protein crystallizes in space group P2(1)2(1)2(1), with unit-cell parameters a = 55.44, b = 61.62, c = 73.43 A, and diffracts beyond 2.00 A resolution.