Varicella-zoster virus in actively spreading segmental vitiligo skin: Pathological, immunochemical, and ultrastructural findings (a first and preliminary study).

Segmental vitiligo (SV) is a unilateral subtype of vitiligo which is clinically characterized by a cutaneous depigmentation and histologically by a melanocyte loss from the epidermis and hair follicle reservoirs. To date, its pathogenesis remains a mystery. In many cases, this skin depigmentation shares several clinical features and dysfunctions with herpes zoster (HZ). So, for the first time, we examined whether any nucleus and cell fusion associated with a positive immunolabelling of varicella-zoster virus (VZV) and VZV mature virions could be found in SV skin samples as in herpes zoster (HZ). A total of 40 SV samples were used for histological and immunochemical studies. Control samples were obtained from three HZ, and 10 generalized vitiligo lesions. For ultrastructural study, three recent SV and one HZ as controls were recruited. Here, we report that nuclear fusion in epidermal cells were statistically associated with recent SV (p < .001), whereas syncytia formation was associated with long-lasting SV (p = .001). A positive detection of VZV antigen was statistically associated in the epidermis with recent SV and in the dermis with long-lasting SV (p = .001). Finally, the discovery of mature virions in 3/3 recent SV samples provides additional arguments for our viral hypothesis.

Vitiligo Skin T Cells Are Prone to Produce Type 1 and Type 2 Cytokines to Induce Melanocyte Dysfunction and Epidermal Inflammatory Response Through Jak Signaling.

Vitiligo is a T cell-mediated inflammatory skin disorder characterized by the loss of epidermal melanocytes. However, the contribution of melanocytes to the physiopathology of the disease in response to the T-cell microenvironment remains unclear. Here, using NanoString technology and multiplex ELISA, we show that active vitiligo perilesional skin is characterized by prominent type 1 and 2 associated immune responses. The vitiligo skin T-cell secretome downregulated melanocyte function and adhesion while increasing melanocyte mitochondrial metabolism and expression of inflammatory cytokines and chemokines by epidermal cells. The Jak1/2 inhibitor ruxolitinib strongly inhibited such effects on epidermal cells. Our data highlight that vitiligo is more complex than previously thought, with prominent combined activities of both T helper type 1- and T helper type 2-related cytokines inducing inflammatory responses of epidermal cells. Melanocytes do not appear only to be a target of T cells in vitiligo but could actively contribute to perpetuate inflammation. Jak inhibitors could prevent the impact of T cells on epidermal cells and pigmentation, highlighting their potential clinical benefit in vitiligo.

Type-1 cytokines regulate MMP-9 production and E-cadherin disruption to promote melanocyte loss in vitiligo.

Loss of melanocytes is the pathological hallmark of vitiligo, a chronic inflammatory skin depigmenting disorder induced by exaggerated immune response, including autoreactive CD8 T cells producing high levels of type 1 cytokines. However, the interplay between this inflammatory response and melanocyte disappearance remains to be fully characterized. Here, we demonstrate that vitiligo skin contains a significant proportion of suprabasal melanocytes, associated with disruption of E-cadherin expression, a major protein involved in melanocyte adhesion. This phenomenon is also observed in lesional psoriatic skin. Importantly, apoptotic melanocytes were mainly observed once cells were detached from the basal layer of the epidermis, suggesting that additional mechanism(s) could be involved in melanocyte loss. The type 1 cytokines IFN-γ and TNF-α induce melanocyte detachment through E-cadherin disruption and the release of its soluble form, partly due to MMP-9. The levels of MMP-9 are increased in the skin and sera of patients with vitiligo, and MMP-9 is produced by keratinocytes in response to IFN-γ and TNF-α. Inhibition of MMP-9 or the JAK/STAT signaling pathway prevents melanocyte detachment in vitro and in vivo. Therefore, stabilization of melanocytes in the basal layer of the epidermis by preventing E-cadherin disruption appears promising for the prevention of depigmentation occurring in vitiligo and during chronic skin inflammation.

Trypanosoma brucei gambiense excreted/secreted factors impair lipopolysaccharide-induced maturation and activation of human monocyte-derived dendritic cells.

Trypanosoma brucei gambiense, an extracellular eukaryotic flagellate parasite, is the main etiological agent of human African trypanosomiasis (HAT) or sleeping sickness. Dendritic cells (DCs) play a pivotal role at the interface between innate and adaptive immune response and are implicated during HAT. In this study, we investigated the effects of T gambiense and its excreted/secreted factors (ESF) on the phenotype of human monocyte-derived DCs (Mo-DCs). Mo-DCs were cultured with trypanosomes, lipopolysaccharide (LPS), ESF derived from T gambiense bloodstream strain Biyamina (MHOM/SD/82), or both ESF and LPS. Importantly, ESF reduced the expression of the maturation markers HLA-DR and CD83, as well as the secretion of IL-12, TNF-alpha and IL-10, in LPS-stimulated Mo-DCs. During mixed-leucocyte reactions, LPS- plus ESF-exposed DCs induced a non-significant decrease in the IFN-gamma/IL-10 ratio of CD4 + T-cell cytokines. Based on the results presented here, we raise the hypothesis that T gambiense has developed an immune escape strategy through the secretion of paracrine mediators in order to limit maturation and activation of human DCs. The identification of the factor(s) in the T gambiense ESF and of the DCs signalling pathway(s) involved may be important in the development of new therapeutic targets.

Vitiligo Skin Is Imprinted with Resident Memory CD8 T Cells Expressing CXCR3.

Vitiligo is a chronic autoimmune depigmenting skin disorder that results from a loss of melanocytes. Multiple combinatorial factors have been involved in disease development, with a prominent role of the immune system, in particular T cells. After repigmentation, vitiligo frequently recurs in the same area, suggesting that vitiligo could involve the presence of resident memory T cells (TRM). We sought to perform a thorough characterization of the phenotype and function of skin memory T cells in vitiligo. We show that stable and active vitiligo perilesional skin is enriched with a population of CD8 TRM expressing both CD69 and CD103 compared with psoriasis and control unaffected skin. CD8 TRM expressing CD103 are mainly localized in the epidermis. Expression of CXCR3 is observed on most CD8 TRM in vitiligo, including the population of melanocyte-specific CD8 T cells. CD8 TRM displayed increased production of IFN-γ and tumor necrosis factor-α with moderate cytotoxic activity. Our study highlights the presence of functional CD8 TRM in both stable and active vitiligo, reinforcing the concept of vitiligo as an immune memory skin disease. The CD8 TRM that remain in stable disease could play a role during disease flares, emphasizing the interest in targeting this cell subset in vitiligo.

Vitiligo-like lesions occurring in patients receiving anti-programmed cell death-1 therapies are clinically and biologically distinct from vitiligo.

BACKGROUND: The use of anti-programmed cell death (PD)-1 therapies in metastatic tumors is associated with cutaneous side effects including vitiligo-like lesions. OBJECTIVE: We sought to characterize clinically and biologically vitiligo-like lesions occurring in patients receiving anti-PD-1 therapies by studying a case series of 8 patients with metastatic tumors and 30 control subjects with vitiligo. METHODS: Eight patients receiving anti-PD-1 therapies with features of vitiligo-like lesions seen in our department were recruited. Clinical features and photographs were analyzed. For some patients, skin and blood samples were obtained. Results were compared with the vitiligo group. RESULTS: All patients developed lesions localized on photoexposed areas with a specific depigmentation pattern consisting of multiple flecked lesions without Koebner phenomenon. In contrast to vitiligo, patients receiving anti-PD-1 therapies who developed vitiligo-like lesions did not report any personal or family histories of vitiligo, thyroiditis, or other autoimmune disorders. Analysis of blood and skin samples revealed increased C-X-C motif ligand 10 levels in serum of patients developing vitiligo-like lesions, associated with skin infiltration of CD8 T-cells expressing C-X-C motif receptor 3 and producing elevated levels of interferon-γ and tumor necrosis factor-alfa. LIMITATIONS: This cross-sectional study concerned a single center. CONCLUSIONS: Clinical and biological patterns of vitiligo-like lesions occurring in patients receiving anti-PD-1 therapies differ from vitiligo, suggesting a different mechanism.

Malvidin-3-O-ß glucoside, major grape anthocyanin, inhibits human macrophage-derived inflammatory mediators and decreases clinical scores in arthritic rats.

Polyphenolic anthocyanins are major colorful compounds in red fruits, known to prevent cardiovascular and other diseases. Grape polyphenols are a mixture of various molecules and their exact contribution to above bioactivities remains to be clarified. In the present study, we first analyzed the effect of purified grape-derived compounds on human peripheral blood mononuclear cell (PBMC) survival, proliferation, as well as for their ability to inhibit the activation of human normal macrophages. Data indicated that malvidin-3-O-ß glucoside (Malßg), the major grape anthocyanin, is bioactive with no toxicity on human PBMC. Malßg decreased the transcription of genes encoding inflammatory mediators, confirmed by the inhibition of TNFα, IL1, IL-6 and iNOS-derived nitric oxide (NO) secretion from activated macrophages. As Malßg also inhibited inflammatory response of rat macrophages, we investigated the anti-inflammatory potential of Malßg in chronic rat adjuvant-induced arthritis (AIA). Malßg significantly diminished inflammatory cachexia and arthritic paw scores in AIA rats at both therapeutic and preventive levels. In vivo effects of Malßg correlated with down-regulation of NO generation from AIA rats' peritoneal macrophages ex vivo. These data indicate that Malßg, major grape anthocyanin, is a potent anti-inflammatory agent in vitro and in vivo, without detectable toxic effect.

Destructive arthritis in a patient with chikungunya virus infection with persistent specific IgM antibodies.

BACKGROUND: Chikungunya fever is an emerging arboviral disease characterized by an algo-eruptive syndrome, inflammatory polyarthralgias, or tenosynovitis that can last for months to years. Up to now, the pathophysiology of the chronic stage is poorly understood. CASE PRESENTATION: We report the first case of CHIKV infection with chronic associated rheumatism in a patient who developed progressive erosive arthritis with expression of inflammatory mediators and persistence of specific IgM antibodies over 24 months following infection. CONCLUSIONS: Understanding the specific features of chikungunya virus as well as how the virus interacts with its host are essential for the prevention, treatment or cure of chikungunya disease.

CD23 mediates antimycobacterial activity of human macrophages.

Engagement of surface receptors contributes to the antimicrobial activity of human immune cells. We show here that infection of human monocyte-derived macrophages (MDM) with live Mycobacterium avium induced the expression of CD23 on their membrane. Subsequent cross-linking of surface CD23 by appropriate ligands induced a dose-dependent antibacterial activity of MDM and the elimination of most infected cells. The stimulation of inducible nitric oxide synthase-dependent generation of NO from MDM after CD23 activation played a major role during their anti-M. avium activity. CD23 activation also induced tumor necrosis factor alpha (TNF-alpha) production from MDM. Mycobacteria reduction was partially inhibited by the addition of neutralizing anti-TNF-alpha antibody to cell cultures without affecting NO levels, which suggested the role of this cytokine for optimal antimicrobial activity. Finally, interleukin-10, a Th2 cytokine known to downregulate CD23 pathway, is shown to decrease NO generation and mycobacteria elimination by macrophages. Therefore, (i) infection with M. avium promotes functional surface CD23 expression on human macrophages and (ii) subsequent signaling of this molecule contributes to the antimicrobial activity of these cells through an NO- and TNF-alpha-dependent pathway. This study reveals a new human immune response mechanism to counter mycobacterial infection involving CD23 and its related ligands.

Molecular blocking of CD23 supports its role in the pathogenesis of arthritis.

BACKGROUND: CD23 is a differentiation/activation antigen expressed by a variety of hematopoietic and epithelial cells. It can also be detected in soluble forms in biological fluids. Initially known as the low-affinity receptor for immunoglobulin E (Fc epsilonRII), CD23 displays various other physiologic ligands such as CD21, CD11b/c, CD47-vitronectin, and mannose-containing proteins. CD23 mediates numerous immune responses by enhancing IgE-specific antigen presentation, regulating IgE synthesis, influencing cell differentiation and growth of both B- and T-cells. CD23-crosslinking promotes the secretion of pro-inflammatory mediators from human monocytes/macrophages, eosinophils and epithelial cells. Increased CD23 expression is found in patients during allergic reactions and rheumatoid arthritis while its physiopathologic role in these diseases remains to be clarified. METHODOLOGY/PRINCIPAL FINDINGS: We previously generated heptapeptidic countrestructures of human CD23. Based on in vitro studies on healthy and arthritic patients' cells, we showed that CD23-specific peptide addition to human macrophages greatly diminished the transcription of genes encoding inflammatory cytokines. This was also confirmed by significant reduction of mediator levels in cell supernatants. We also show that CD23 peptide decreased IgE-mediated activation of both human and rat CD23(+) macrophages. In vivo studies in rat model of arthritis showed that CD23-blocking peptide ameliorates clinical scores and prevent bone destruction in a dose dependent manner. Ex-vivo analysis of rat macrophages further confirmed the inhibitory effect of peptides on their activation. Taken together our results support the role of CD23 activation and subsequent inflammatory response in arthritis. CONCLUSION: CD23-blocking peptide (p30A) prevents the activation of monocytes/macrophages without cell toxicity. Thus, targeting CD23 by antagonistic peptide decreases inflammatory markers and may have clinical value in the treatment of human arthritis and allergic reactions involving CD23.

Rutoside decreases human macrophage-derived inflammatory mediators and improves clinical signs in adjuvant-induced arthritis.

BACKGROUND: Dietary flavonols may play an important role in the adjunct therapy of chronic inflammation. The availability of therapeutic formulations of pentahydroxyflavone glycoside, rutoside (RU), led us to investigate the ability of this molecule to modulate the release of various proinflammatory mediators from human activated macrophages in vitro and to ameliorate arthritic markers in a rat model. METHODS: RU was added simultaneously to human macrophages during their activation. Cells were then analyzed for inflammation-related gene expression using a specific array, and cell supernatants were collected to measure inflammatory mediators. RU was also injected into adjuvant-induced arthritic rats, and disease progression and body weight were evaluated until 50 days after injection. Sera and peritoneal macrophages were also collected to quantify the RU effect on various inflammatory markers. RESULTS: RU inhibited inflammation-related gene expression in activated human macrophages and the release of nitric oxide, tumor necrosis factor-alpha, interleukin (IL)-1, and IL-6 from these cells. In a rat model, RU inhibited clinical signs of chronic arthritis, correlating with decreased levels of inflammatory cytokines detected in rat sera and macrophage supernatants. CONCLUSION: Thus, RU may have clinical value in reducing inflammatory manifestations in human arthritis and other inflammatory diseases.

Therapeutic and preventive properties of quercetin in experimental arthritis correlate with decreased macrophage inflammatory mediators.

Pentahydroxyflavone dihydrate, quercetin (QU) is one of common flavonols biosynthesized by plants and has been suggested to modulate inflammatory responses in various models. In the present study, we investigated in vivo effects of oral or intra-cutaneous QU in chronic rat adjuvant-induced arthritis (AA). Growth delay and arthritic scores were evaluated daily after AA induction in Lewis rats. Oral administration of QU (5 x 160 mg/kg) to arthritic rats resulted in a clear decrease of clinical signs compared to untreated controls. Intra-cutaneous injections of lower doses (5 x 60 mg/kg) of QU gave similar anti-arthritic effects, while 5 x 30 mg/kg concentrations were inefficient in this respect. Finally, injection of relatively low QU doses (5 x 30 mg/kg) prior to AA induction significantly reduced arthritis signs. As QU was suggested to inhibit macrophage-derived cytokines and nitric oxide (NO), we then analyzed macrophage response ex vivo. Anti-arthritic effects of QU correlated with significant decrease of inflammatory mediators produced by peritoneal macrophages, ex vivo and in vitro. These data indicate that QU is a potential anti-inflammatory therapeutic and preventive agent targeting the inflammatory response of macrophages.

Quercetin induces apoptosis of Trypanosoma brucei gambiense and decreases the proinflammatory response of human macrophages.

In addition to parasite spread, the severity of disease observed in cases of human African trypanosomiasis (HAT), or sleeping sickness, is associated with increased levels of inflammatory mediators, including tumor necrosis factor (TNF)-alpha and nitric oxide derivatives. In the present study, quercetin (3,3',4',5,7-pentahydroxyflavone), a potent immunomodulating flavonoid, was shown to directly induce the death of Trypanosoma brucei gambiense, the causative agent of HAT, without affecting normal human cell viability. Quercetin directly promoted T. b. gambiense death by apoptosis as shown by Annexin V binding. In addition to microbicidal activity, quercetin induced dose-dependent decreases in the levels of TNF-alpha and nitric oxide produced by activated human macrophages. These results highlight the potential use of quercetin as an antimicrobial and anti-inflammatory agent for the treatment of African trypanomiasis.