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A possible etiological link between the onset of endemic pemphigus in Tunisia and bites of Phlebotomus papatasi, the vector of zoonotic cutaneous leishmaniasis, has been previously suggested. We hypothesized that the immunodominant P. papatasi salivary protein PpSP32 binds to desmogleins 1 and 3 (Dsg1 and Dsg3), triggering loss of tolerance to these pemphigus target autoantigens. Here, we show using far-Western blot that the recombinant PpSP32 protein (rPpSP32) binds to epidermal proteins with a MW of approximately 170 kDa. Coimmunoprecipitation revealed the interaction of rPpSP32 with either Dsg1 or Dsg3. A specific interaction between PpSP32 and Dsg1 and Dsg3 was further demonstrated by ELISA assays. Finally, mice immunized with rPpSP32 twice per week exhibited significantly increased levels of anti-Dsg1 and -Dsg3 antibodies from day 75 to 120. Such antibodies were specific for Dsg1 and Dsg3 and were not the result of cross-reactivity to PpSP32. In this study, we demonstrated for the first time to our knowledge a specific binding between PpSP32 and Dsg1 and Dsg3, which might underlie the triggering of anti-Dsg antibodies in patients exposed to sand fly bites. We also confirmed the development of specific anti-Dsg1 and -Dsg3 antibodies in vivo after PpSP32 immunization in mice. Collectively, our results provide evidence that environmental factors, such as the exposure to P. papatasi bites, can trigger the development of autoimmune antibodies.

The role of the bone marrow microenvironment in supporting the proliferation and survival of the abnormal plasma cells in multiple myeloma (MM) is well established. Such microenvironment is rich of cytokines like IL-6, TGF-β, IL-1 and IL-23 which are known to promote the differentiation of Th17 lymphocytes, a T helper subpopulation. Th17 cells secrete IL-17, a cytokine involved in the pathophysiology of several auto-immune diseases. Yet, its involvement in cancers remains unclear. Herein, we aimed to try to understand the role of Th17 lymphocytes in multiple myeloma. Bone marrow samples were prospectively collected from 29 MM patients and 23 healthy bone marrow donors for allograft. Mononuclear bone marrow cells were isolated by Ficoll-Hypaque gradient and CD138 + plasma cells were depleted using magnetic beads. The quantification of Th17 cells was performed by flow cytometry in the CD138 negative cells. The mRNA expression of IL17 and RORc was quantified using real time PCR in the same subset. The mRNA expression of IL17R was analyzed in plasma cells (CD138 + cells). Data obtained from patients and healthy donors were compared by both non-parametric Mann-Whitney U test and Spearman test. A significant increase of IL17 and RORC mRNA expression was found in the bone marrow microenvironment of MM patients compared to healthy donors. Th17 cells were also increased in the bone marrow of MM patients compared to healthy donors. Interestingly, the mRNA expression of IL17R was significantly decreased in MM patients. Yet, no correlation was found between the gene expression IL17, RORC and IL17R and the bone marrow infiltration or the stage of the disease. Collectively, our results suggest the involvement of Th17 cells in the pathophysiology of MM. Such data further support the use of anti-IL-17 antibodies as a therapeutic approach in MM., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2020. Published by Elsevier Ltd.)

Objectives: Diagnosis of SARS-CoV-2 infection is a major public health issue. In a context of limited diagnostic capacity with the reference technique (real-time RT-PCR), many manufacturers have developed rapid diagnostic tests (RDTs). Although very promising in theory, these tests have raised many questions. This article is a rapid review that synthesizes data regarding different types of available RDTs, their performance, their limits and their potential indications in Tunisia as proposed by a multidisciplinary group of experts., Methods: A literature review was carried out on the websites of international organizations, governmental bodies and on INAHTA database, completed by a search of relevant scientific articles up to 1 June 2020. The synthesis of the data was submitted to a panel of experts to propose recommendations for the Tunisian context., Results: RDTs based on the detection of antigens and antibodies have sensitivity and specificity related issues. Few validation reports are published in the scientific literature. Pending more evidence on their performance and validity, several international organizations recommend their use only for research purposes. TDRs based on antibody detection are not appropriate for the early diagnosis of COVID-19. However, validated and specific tests could provide complementary diagnostic information to reference tests., Conclusion: Pending further evidence, the panel recommends the use of RDTs mainly for research purposes at the community level.

Introduction: Zoonotic cutaneous leishmaniasis (ZCL), due to infection by Leishmania (L). major, is characterized by polymorphic clinical manifestations which could be attributed to the host's immune response. In this study we investigated the involvement of cytotoxic cells on the outcome of the disease., Methods: Expression of granzyme B (GrB), granulysine (Grly), and interferon (IFN)-γ was evaluated within ZCL lesion specimens using the technique of real-time quantitative polymerase chain reaction (RT-qPCR). Immunohistochemical staining was performed using anti-CD3, CD4, CD8, CD56, GrB, and IFN-γ antibodies to identify the phenotype of GrB and IFN-γ-producing cells., Results: GrB and Grly mRNA was detected within 75% and 80% of ZCL lesions, respectively. Statistical analysis demonstrated a significant correlation between levels of GrB and Grly. Interestingly, expression of these molecules correlates negatively with the lesion's age. The highest levels were measured in early lesions (E-ZCL) (lesion age ≤1 month) comparing to late lesions (L-ZCL) (lesion age >1 month). Otherwise, IFN-γ mRNA was detected only within 56% and a positive correlation was found between levels of this cytokine and those of GrB. Immunohistochemical analysis showed that GrB is produced essentially by CD8 + T cells whereas IFN-γ is produced by both CD4 + and CD8 + T cells., Conclusion: Together our results demonstrate the presence of cytotoxic cells producing GrB and Grly within leishmaniasis cutaneous lesions., (© 2019 The Authors. Immunity, Inflammation and Disease published by John Wiley & Sons Ltd.)

Leishmaniases are neglected diseases, caused by intracellular protozoan parasites of the Leishmania ( L .) genus. Although the principal host cells of the parasites are macrophages, neutrophils are the first cells rapidly recruited to the site of parasites inoculation, where they play an important role in the early recognition and elimination of the parasites. The nature of early interactions between neutrophils and Leishmania could influence the outcome of infection. Herein we aimed to evaluate whether different Leishmania strains, responsible for distinct clinical manifestations, could influence ex vivo functional activity of neutrophils. Human polymorphonuclear leukocytes were isolated from 14 healthy volunteers and the ex vivo infection of these cells was done with two L. infantum and one L. major strains. Infection parameters were determined and neutrophils activation was assessed by oxidative burst, degranulation, DNA release and apoptosis; cytokine production was measured by a multiplex flow cytometry analysis. Intracellular amastigotes were rescued to determine Leishmania strains survival. The results showed that L. infantum and L. major promastigotes similarly infected the neutrophils. Oxidative burst, neutrophil elastase, myeloperoxidase activity and apoptosis were significantly increased in infected neutrophils but with no differences between strains. The L. infantum -infected neutrophils induced more DNA release than those infected by L. major . Furthermore, Leishmania strains induced high amounts of IL-8 and stimulated the production of IL-1β, TNF-α, and TGF-β by human neutrophils. We observed that only one strain promoted IL-6 release by these neutrophils. The production of TNF-α was also differently induced by the parasites strains. All these results demonstrate that L. infantum and L. major strains were able to induce globally a similar ex vivo activation and apoptosis of neutrophils; however, they differentially triggered cytokines release from these cells. In addition, rescue of intracellular parasites indicated different survival rates further emphasizing on the influence of parasite strains within a species on the fate of infection.

Aims: Maturity Onset Diabetes of the Young (MODY) is a monogenic form of diabetes with autosomal dominant inheritance pattern. The diagnosis of MODY and its subtypes is based on genetic testing. Our aim was investigating MODY by means of next-generation sequencing in the Tunisian population., Methods: We performed a targeted sequencing of 27 genes known to cause monogenic diabetes in 11 phenotypically suspected Tunisian patients. We retained genetic variants passing filters of frequency in public databases as well as their probable effects on protein structures and functions evaluated by bioinformatics prediction tools., Results: Five heterozygous variants were found in four patients. They include two mutations in HNF1A and GCK that are the causative genes of the two most prevalent MODY subtypes described in the literature. Other possible mutations, including novel frameshift and splice-site variants were identified in ABCC8 gene., Conclusions: Our study is the first to investigate the clinical application of targeted next-generation sequencing for the diagnosis of MODY in Africa. The combination of this approach with a filtering/prioritization strategy made a step towards the identification of MODY mutations in the Tunisian population.

Myasthenia gravis (MG) with antibodies to the muscle-specific tyrosine kinase (MuSK-MG) receptor is a rare entity. It represents 5 to 8% of all MG patients. Few pediatric cases were reported. Clinical presentation is often atypical. It is characterized by predominant involvement of cranial, bulbar, and axial muscles and early respiratory crises. Myokymia and fasciculation are suggestive of MuSK-MG. The clinical course of patients with MuSK-MG is worse than other types of MG. Responses to standard therapies are variable. We report clinical, neurophysiological, serological, and outcome profile of a Tunisian child with MuSK-MG., Competing Interests: None declared., (Georg Thieme Verlag KG Stuttgart · New York.)

The aromatic hydrocarbons receptor (AhR) is a ligand-dependent transcription factor that plays a role in mediating toxicity to xenobiotics. Its key role in immune regulation has been recently demonstrated. Recent data pointed to the efficacy of ITE (2-(1'H-indole-3'-carbonyl)-thiazole-4-carboxylic acid methyl ester), a nontoxic ligand of AhR, in experimental models of inflammatory diseases. Such effect was mainly through the expansion of regulatory T cells (Tregs). Similarly, TCDD (2,3,7,8-tetrachlorodibenzo-p-dioxin), a toxic ligand of AhR, has been shown to exert comparable effects on Tregs in mice. Herein, we showed that ITE has no effects on natural Tregs. However, it supports the de novo generation of Tregs in humans while promoting their suppressive functions. Our data bring new elements supporting the use of ITE in human therapy of inflammatory diseases., (©2018 Society for Leukocyte Biology.)

Lesion features in cutaneous leishmaniasis (CL) depend on the infecting Leishmania species as well as on host immune reponse. In this study, we evaluated the histological and immunological differences between two forms of CL described in Tunisia: zoonotic cutaneous leishmaniasis (ZCL) caused by L. major and sporadic cutaneous leishmaniasis (SCL) caused by L. infantum. Histological analysis showed a mild to moderate infiltrate within ZCL lesions. In contrast, massive infiltration of the dermis was observed within SCL lesions. Contrary to ZCL, infiltrates within SCL lesions were organized and showed granuloma composed of macrophages and lymphocytes. In addition, immunohistochemical analysis showed a predominance of CD4 + T cells within both CL forms. Furthermore, expression of interferon-γ, interleukin (IL)-10, IL-8, IL-13 and monocyte chemotactic protein (MCP)-1 was evaluated using real-time quantitative polymerase chain reaction (RT-qPCR). MCP-1 and IL-10 were expressed at comparable levels in ZCL and SCL lesions. Interestingly, IL-8 mRNA levels were significantly higher in ZCL lesions compared to SCL lesions, but interferon-γ was significantly higher in SCL lesions than in ZCL lesions., (© T. Boussoffara et al., published by EDP Sciences, 2019.)

Zoonotic cutaneous leishmaniasis (ZCL) caused by Leishmania (L.) major infection is characterized by different clinical presentations which depend in part on the host factors. In attempt to investigate the impact of the host's immune response in the outcome of the disease, we conducted a prospective study of 453 individuals living in endemic foci of L. major transmission in Central Tunisia. Several factors were assessed at the baseline including (i) the presence of typical scars of ZCL, (ii) in vivo hypersensitivity reaction to leishmanin, and (iii) the in vitro release of granzyme B (Grz B) by peripheral blood mononuclear cells (PBMC) in response to stimulation with live L. major promastigotes. After one season of parasite's transmission, repeated clinical examinations allowed us to diagnose the new emerging ZCL cases. Heterogeneity was observed in terms of number of lesions developed by each individual as well as their size and spontaneous outcome, which led us to establish the parameter "severity of the disease." The efficacy of the presence of typical ZCL scar, the leishmanin skin test (LST) positive reactivity and the high levels of Grz B (≥2 ng/ml), in the protection against the development of ZCL were 29, 15, and 22%, respectively. However, these factors were more efficient against development of intermediate or severe forms of ZCL. Levels of Grz B >2 ng/ml showed the best efficacy of protection (equals to 72.8%) against development of these forms of ZCL. The association of such parameter with the positivity of the LST exhibited a better efficacy (equals to 83.6%). In conclusion, our results support the involvement of Leishmania -specific cytotoxic cellular immune response in host protection against Leishmania -infection. This factor could be of great interest in monitoring the success of vaccination against human leishmaniasis.

The mechanisms leading to the disruption of self-tolerance in systemic lupus erythematosus (SLE) remain elusive. Herein, we aimed to decipher the molecular basis of the impaired response of mononuclear cells to TGF-β1. The Smad3-pathway was explored on CD3+ lymphocytes in either active or non active SLE patients. An impaired transcription of TGF-β1 target genes was demonstrated in the CD3+ lymphocytes of active SLE patients confirming that the defect involves T cells and pointing to its extrinsic nature. We further demonstrate that the defect did not result from an impaired TGF-βRII expression or Smad2/3 phosphorylation suggesting that the mechanism lies downstream Smad2/3 translocation. Interestingly, the TGF-1 signaling defect did not correlate with an increased expression of soluble or membrane-bound IL-15. However, it was associated with an overexpression of IL-22. This suggests that an excessive activation of AhR pathway (through UV radiations, infections, etc.) could lead to the inhibition of immunosuppressive actions of TGF-β thus disrupting immune homeostasis in SLE. Collectively, our data suggest that the impaired response to TGF-β in SLE patients is associated with disease activity and provide new insights into the pathogenesis of SLE since it could establish the link between the environmental factors and the aberrancies of the immune system usually described in SLE., (Copyright © 2018 Elsevier Ltd. All rights reserved.)

Introduction: Anti-glutamic acid decarboxylase (anti-GAD65) antibodies are a rare cause of autoimmune encephalitis. This entity is mainly recognized in adults and very few cases were reported in children. We report on a paediatric case of anti-GAD encephalitis with severe presentation and uncontrollable dysautonomia., Case Study: A 9-year-old girl was referred to our department for refractory seizures and behavioral disturbances. Brain magnetic resonance imaging (MRI) was normal. Repeat screening for antineuronal antibodies showed negative results for anti-NMDA receptor antibodies but positive results for anti-GAD65 with a low positivity of anti-Ma2 antibodies. Although a transient improvement was noticed after immunomodulatory treatment, the patient developed severe intractable autonomic imbalance including dysrythmia, alternating bradycardia/tachycardia, hypotension/hypertension, hypothermia/hyperthermia and hyperhidrosis. She deceased six months after onset., Conclusion: Our report intends to raise awareness of autoimmune encephalitis with anti-GAD65 antibodies which may involve extralimbic brain regions and manifest with fatal dysautonomia. We highlight the need for prompt diagnosis and aggressive management for this underdiagnosed entity in children., (Copyright © 2018 European Paediatric Neurology Society. Published by Elsevier Ltd. All rights reserved.)

Nowadays, there is no available vaccine for human leishmaniasis. Animal experiments demonstrate that pre-exposure to sand fly saliva confers protection against leishmaniasis. Our preceding work in humans indicates that Phlebotomus papatasi saliva induces the production of IL-10 by CD8+ T lymphocytes. The neutralization of IL-10 enhanced the activation of a T-cell CD4+ population-producing IFN-γ. Herein, we used a biochemical and functional genomics approach to identify the sand fly salivary components that are responsible for the activation of the T helper type 1 immune response in humans, therefore constituting potential vaccine candidates against leishmaniasis. Fractionated P. papatasi salivary extracts were first tested on T lymphocytes of immune donors. We confirmed that the CD4+ lymphocytes proliferate and produce IFN-γ in response to stimulation with the proteins of molecular weight >30 kDa. Peripheral blood mononuclear cells from immune donors were transfected with plasmids coding for the most abundant proteins from the P. papatasi salivary gland cDNA library. Our result showed that the "yellow related proteins," PPTSP42 and PPTSP44, and "apyrase," PPTSP36, are the proteins responsible for the aforementioned cellular immune response and IFN-γ production. Strikingly, PPTSP44 triggered the highest level of lymphocyte proliferation and IFN-γ production. Multiplex cytokine analysis confirmed the T helper type 1-polarized response induced by these proteins. Importantly, recombinant PPTSP44 validated the results observed with the DNA plasmid, further supporting that PPTSP44 constitutes a promising vaccine candidate against human leishmaniasis., (Copyright © 2017 The Authors. Published by Elsevier Inc. All rights reserved.)

Aims: Acetamiprid (ACE) is an insecticide of the neonicotinoid family, the most widely used in the world. Herein, we assessed the effect of ACE on either the humoral or cellular immune responses of rodents. We also evaluated the role of curcumin in the restoration of altered immune responses after ACE treatment., Methods: Five groups of five Swiss Albino mice were immunized intraperitoneally with the recombinant form of CFP32, a virulence factor of Mycobacterium tuberculosis. One group received ACE (5mg/kg) during 61days, a second one received ACE associated with curcumin (100mg/kg). Three control groups were included; one untreated, the second received corn oil and the third received curcumin alone. The humoral immune response was assessed by ELISA testing the anti-rCFP32 antibody concentrations in the serum. The cellular immune response was assessed by analyzing the cellular proliferation of the splenocytes stimulated in vitro by a mitogen or rCFP32., Results: The ACE-treated mice showed a significant immunosuppression of the specific humoral response with a restorative effect of curcumin when administered with ACE. Similarly, ACE significantly decreased the level of splenocyte proliferation after either a non specific or a specific activation. Curcumin partially restores the antigen specific cellular immune response. Moreover, when administered alone, curcumin significantly inhibits the proliferative responses to the mitogen confirming its anti-mitogenic effect. Histological analysis showed alteration of spleens of mice exposed to ACE., Significance: Altogether, our data indicated that ACE could potentially be harmful to the immune system., (Copyright © 2017. Published by Elsevier Inc.)

Sustained activation of JAK/STAT3 signaling pathway is classically described in Multiple Myeloma (MM). One explanation could be the silencing of the JAK/STAT suppressor genes, through the hypermethylation of SHP-1 and SOCS-1, previously demonstrated in MM cell lines or in whole bone marrow aspirates. The link between such suppressor gene silencing and the degree of bone marrow invasion or the treatment response has not been evaluated in depth. Using real-time RT-PCR, we studied the expression profile of three JAK/STAT suppressor genes: SHP-1, SHP-2 and SOCS-1 in plasma cells freshly isolated from the bone marrows of MM patients and healthy controls. Our data demonstrated an abnormal repression of such genes in malignant plasma cells and revealed a significant correlation between such defects and the sustained activation of the JAK/STAT3 pathway during MM. The repressed expression of SHP-1 and SHP-2 correlated significantly with a high initial degree of bone marrow infiltration but was, unexpectedly, associated with a better response to the induction therapy. Collectively, our data provide new evidences that substantiate the contribution of JAK/STAT suppressor genes in the pathogenesis of MM. They also highlight the possibility that the decreased gene expression of SHP-1 and SHP-2 could be of interest as a new predictive factor of a favorable treatment response, and suggest new potential mechanisms of action of the therapeutic molecules. Whether such defect helps the progression of the disease from monoclonal gammopathy of unknown significance to MM remains, however, to be determined.

Background: Epidemiological features and trends of cutaneous melanoma (CM) in North-African populations remain unclear. Those populations are of particular interest as they belong to a mosaic of various other origins (sub-Saharan, European Ancestry, and North-African Berbers). The aim of this study is to draw epidemiological profile and clinicopathological features of CM in the Tunisian population., Methods: Incidence analyses were based on data from regional cancer registries. Clinical data were collected from dermatological departments and xeroderma pigmentosum (XP) referral centers and provided CM clinicopathological characteristics and progression. Statistical analyses were achieved using R packages and SPSS 20.0., Results: The incidence of CM in Tunisia is relatively low (0.5-0.7 per 100,000 inhabitants per year). Gender differences were observed regarding anatomical distribution (P = 0.004). Acral lentiginous melanoma (ALM) was the most frequent histological subtype (32.3%); however, nodular melanoma (NM) was the most aggressive and responsible for 54.8% of deaths. CM in XP patients develops at a median age that is 42 years earlier than sporadic cases, with preferential localization on the head and neck (P < 0.001). Finally, male patients exhibited survival disadvantages compared with females (adjusted hazard ratio (HR) = 2.22, 95% CI: 1.05-4.68, P = 0.037)., Conclusions: Cutaneous melanoma features in Tunisia are closer to those of non-Caucasians, even though gender differences that are similar to those observed in Caucasians were uncovered. This study also emphasizes the aggressiveness of NM and its effect on melanoma patient deaths. Xeroderma pigmentosum stands as the major predisposing host factor., (© 2016 The International Society of Dermatology.)