Ma C.S.,Garvan Institute of Medical Research |
Wong N.,Garvan Institute of Medical Research |
Rao G.,Garvan Institute of Medical Research |
Nguyen A.,Garvan Institute of Medical Research |
And 62 more authors.
Journal of Experimental Medicine | Year: 2016
Naive CD4+ T cells differentiate into specific effector subsets-Th1, Th2, Th17, and T follicular helper (Tfh)-that provide immunity against pathogen infection. The signaling pathways involved in generating these effector cells are partially known. However, the effects of mutations underlying human primary immunodeficiencies on these processes, and how they compromise specific immune responses, remain unresolved. By studying individuals with mutations in key signaling pathways, we identified nonredundant pathways regulating human CD4+ T cell differentiation in vitro. IL12Rβ1/TYK2 and IFN-γR/STAT1 function in a feed-forward loop to induce Th1 cells, whereas IL-21/IL-21R/STAT3 signaling is required for Th17, Tfh, and IL-10-secreting cells. IL12Rβ1/ TYK2 and NEMO are also required for Th17 induction. Strikingly, gain-of-function STAT1 mutations recapitulated the impact of dominant-negative STAT3 mutations on Tfh and Th17 cells, revealing a putative inhibitory effect of hypermorphic STAT1 over STAT3. These findings provide mechanistic insight into the requirements for human T cell effector function, and explain clinical manifestations of these immunodeficient conditions. Furthermore, they identify molecules that could be targeted to modulate CD4+ T cell effector function in the settings of infection, vaccination, or immune dysregulation. © 2016 Ma et al.
Perez De Diego R.,University Institute of La Paz |
Mulvey C.,University College London |
Mulvey C.,University of Cambridge |
Casanova J.-L.,Laboratory of Human Genetics of Infectious Diseases |
And 5 more authors.
Expert Review of Proteomics | Year: 2014
The genetic theory of infectious diseases has proposed that susceptibility to life-threatening infectious diseases in childhood, occurring in the course of primary infection, results mostly from individually rare but collectively diverse single-gene variants. Recent evidence of an ever-expanding spectrum of genes involved in susceptibility to infectious disease indicates that the paradigm has important implications for diagnosis and treatment. One such pathology is childhood herpes simplex encephalitis, which shows a pattern of rare but diverse disease-disposing genetic variants. The present report shows how proteomics can help to understand susceptibility to childhood herpes simplex encephalitis and other viral infections, suggests that proteomics may have a particularly important role to play, emphasizes that variation over the population is a critical issue for proteomics and notes some new challenges for proteomics and related bioinformatics tools in the context of rare but diverse genetic defects. © 2014 Informa UK, Ltd.
Jeremiah N.,French Institute of Health and Medical Research |
Jeremiah N.,University of Paris Pantheon Sorbonne |
Neven B.,French Institute of Health and Medical Research |
Neven B.,University of Paris Pantheon Sorbonne |
And 33 more authors.
Journal of Clinical Investigation | Year: 2014
Innate immunity to viral infection involves induction of the type I IFN response; however, dysfunctional regulation of this pathway leads to inappropriate inflammation. Here, we evaluated a nonconsanguineous family of mixed European descent, with 4 members affected by systemic inflammatory and autoimmune conditions, including lupus, with variable clinical expression. We identified a germline dominant gain-of-function mutation in TMEM173, which encodes stimulator of type I IFN gene (STING), in the affected individuals. STING is a key signaling molecule in cytosolic DNA-sensing pathways, and STING activation normally requires dimerization, which is induced by 2′3′ cyclic GMP-AMP (cGAMP) produced by the cGAMP synthase in response to cytosolic DNA. Structural modeling supported constitutive activation of the mutant STING protein based on stabilized dimerization. In agreement with the model predictions, we found that the STING mutant spontaneously localizes in the Golgi of patient fibroblasts and is constitutively active in the absence of exogenous 2′3′-cGAMP in vitro. Accordingly, we observed elevated serum IFN activity and a type I IFN signature in peripheral blood from affected family members. These findings highlight the key role of STING in activating both the innate and adaptive immune responses and implicate aberrant STING activation in features of human lupus. © 2014, American Society for Clinical Investigation. All rights reserved.
Mazerolles F.,French Institute of Health and Medical Research |
Mazerolles F.,Paris-Sorbonne University |
Picard C.,Paris-Sorbonne University |
Picard C.,Laboratory of Human Genetics of Infectious Diseases |
And 10 more authors.
Journal of Allergy and Clinical Immunology | Year: 2013
Background: The generation of high-affinity antibodies requires the presence of a population of CD4+ T cells (follicular TH [TFH] cells) in the lymph node follicles. These cells differ from TH1, TH2, and TH17 effector cells in that they strongly express activation markers and the chemokine receptor CXCR5 and secrete large amounts of IL-21 and CXCL13. Small numbers of nonactivated CD4 +CD45RO+CXCR5+ T cells are also found in the blood. Objective: We sought to obtain in vitro a population close to the T FH cells and to study the presence of this cell population among patients with autosomal dominant hyper-IgE syndrome carrying heterozygous signal transducer and activator of transcription 3 (STAT3) mutations that impair the IL-21 signaling required for B-cell differentiation. Methods: CD4 +CD45RO+CXCR5+ T cells were isolated from blood and activated by CD3/T-cell receptor. Results: We found that CD4 +CD45RO+CXCR5+ activated T cells corresponding to circulating bona fide memory TFH cells and that STAT3-deficient patients have abnormally low numbers of "TFH-like" blood T cells. However, STAT3-deficient TFH cells have much the same phenotypic and functional characteristics as TFH cells from healthy control subjects. The ability of STAT3-deficient TFH cells to produce IL-21 on CD28/T-cell receptor activation and to proliferate did not differ from that observed for control TFH cells in vitro. Although the STAT3-deficient TFH cells were also able to help control B cells to produce IgG and IgA, induction of IgG production by naive B cells was impaired. Conclusion: Heterozygous mutations in STAT3 lead to reduced numbers of circulating TFH-like cells, a finding that might account (at least in part) for the observed defect in antibody production. © 2013 American Academy of Allergy, Asthma & Immunology.
Patin E.,Laboratory of Human Genetics of Infectious Diseases |
Patin E.,University of Paris Descartes |
Kutalik Z.,University of Lausanne |
Kutalik Z.,Swiss Institute of Bioinformatics |
And 44 more authors.
Gastroenterology | Year: 2012
Background & Aims: Polymorphisms in IL28B were shown to affect clearance of hepatitis C virus (HCV) infection in genome-wide association (GWA) studies. Only a fraction of patients with chronic HCV infection develop liver fibrosis, a process that might also be affected by genetic factors. We performed a 2-stage GWA study of liver fibrosis progression related to HCV infection. Methods: We studied well-characterized HCV-infected patients of European descent who underwent liver biopsies before treatment. We defined various liver fibrosis phenotypes on the basis of METAVIR scores, with and without taking the duration of HCV infection into account. Our GWA analyses were conducted on a filtered primary cohort of 1161 patients using 780,650 single nucleotide polymorphisms (SNPs). We genotyped 96 SNPs with P values <5 × 10 -5 from an independent replication cohort of 962 patients. We then assessed the most interesting replicated SNPs using DNA samples collected from 219 patients who participated in separate GWA studies of HCV clearance. Results: In the combined cohort of 2342 HCV-infected patients, the SNPs rs16851720 (in the total sample) and rs4374383 (in patients who received blood transfusions) were associated with fibrosis progression (Pcombined = 8.9 × 10-9 and 1.1 × 10-9, respectively). The SNP rs16851720 is located within RNF7, which encodes an antioxidant that protects against apoptosis. The SNP rs4374383, together with another replicated SNP, rs9380516 (Pcombined = 5.4 × 10-7), were linked to the functionally related genes MERTK and TULP1, which encode factors involved in phagocytosis of apoptotic cells by macrophages. Conclusions: Our GWA study identified several susceptibility loci for HCV-induced liver fibrosis; these were linked to genes that regulate apoptosis. Apoptotic control might therefore be involved in liver fibrosis. © 2012 AGA Institute.
Ma C.S.,Garvan Institute of Medical Research |
Ma C.S.,University of New South Wales |
Avery D.T.,Garvan Institute of Medical Research |
Chan A.,Garvan Institute of Medical Research |
And 30 more authors.
Blood | Year: 2012
T follicular helper (Tfh) cells are critical for providing the necessary signals to induce differentiation of B cells into memory and Ab-secreting cells. Accordingly, it is important to identify the molecular requirements for Tfh cell development and function. We previously found that IL-12 mediates the differentiation of human CD4 + T cells to the Tfh lineage, because IL-12 induces naive human CD4 + T cells to acquire expression of IL-21, BCL6, ICOS, and CXCR5, which typify Tfh cells. We have now examined CD4 + T cells from patients deficient in IL-12Rp1, TYK2, STAT1, and STAT3 to further explore the pathways involved in human Tfh cell differentiation. Although STAT1 was dispensable, mutations in IL12RB1, TYK2, or STAT3 compromised IL-12-induced expression of IL-21 by human CD4 + T cells. Defective expression of IL-21 by STAT3-deficient CD4 + T cells resulted in diminished B-cell helper activity in vitro. Importantly, mutations in STAT3, but not IL12RB1 or TYK2, also reduced Tfh cell generation in vivo, evidenced by decreased circulating CD4 +CXCR5 + T cells. These results highlight the nonredundant role of STAT3 in human Tfh cell differentiation and suggest that defective Tfh cell development and/or function contributes to the humoral defects observed in STAT3-deficient patients. © 2012 by The American Society of Hematology.
Perez De Diego R.,Laboratory of Human Genetics of Infectious Diseases |
Perez De Diego R.,University of Paris Descartes |
Perez De Diego R.,Rockefeller University |
Perez De Diego R.,University Institute of La Paz |
And 21 more authors.
Journal of Allergy and Clinical Immunology | Year: 2013
Background: Inborn errors in Toll-like receptor 3 (TLR3)-IFN type I and III pathways have been implicated in susceptibility to herpes simplex virus encephalitis (HSE) in children, but most patients studied do not carry mutations in any of the genes presently associated with HSE susceptibility. Moreover, many patients do not display any TLR3-IFN-related fibroblastic phenotype. Objective: To study other signaling pathways downstream of TLR3 and/or other independent pathways that may contribute to HSE susceptibility. Methods: We used the stable isotope labeling of amino acids in cell culture proteomics methodology to measure changes in the human immortalized fibroblast proteome after TLR3 activation. Results: Cells from healthy controls were compared with cells from a patient with a known genetic etiology of HSE (UNC-93B -/-) and also to cells from an HSE patient with an unknown gene defect. Consistent with known variation in susceptibility of individuals to viral infections, substantial variation in the response level of different healthy controls was observed, but common functional networks could be identified, including upregulation of superoxide dismutase 2. The 2 patients with HSE studied show clear differences in functional response networks when compared with healthy controls and also when compared with each other. Conclusions: The present study delineates a number of novel proteins, TLR3-related pathways, and cellular phenotypes that may help elucidate the genetic basis of childhood HSE. Furthermore, our results reveal superoxide dismutase 2 as a potential therapeutic target for amelioration of the neurologic sequelae caused by HSE. © 2013 American Academy of Allergy, Asthma & Immunology.
Alves de Medeiros A.K.,Ghent University |
Lodewick E.,Ghent University |
Bogaert D.J.A.,Ghent University |
Haerynck F.,Ghent University |
And 20 more authors.
Journal of Clinical Immunology | Year: 2016
Chronic mucocutaneous or invasive fungal infections are generally the result of primary or secondary immune dysfunction. Patients with autosomal recessive CARD9 mutations are also predisposed to recurrent mucocutaneous and invasive fungal infections with Candida spp., dermatophytes (e.g. Trichophyton spp.) and phaeohyphomycetes (Exophiala spp., Phialophora verrucosa). We study a consanguineous family of Turkish origin in which three members present with distinct clinical phenotypes of chronic mucocutaneous and invasive fungal infections, ranging from chronic mucocutaneous candidiasis (CMC) in one patient, treatment-resistant cutaneous dermatophytosis and deep dermatophytosis in a second patient, to CMC with Candida encephalitis and endocrinopathy in a third patient. Two patients consented to genetic testing and were found to have a previously reported homozygous R70W CARD9 mutation. Circulating IL-17 and IL-22 producing T cells were decreased as was IL-6 and granulocyte/macrophage colony–stimulating factor (GM-CSF) secretion upon stimulation with Candida albicans. Patients with recurrent fungal infections in the absence of known immunodeficiencies should be analyzed for CARD9 gene mutations as the cause of fungal infection predisposition. © 2016, Springer Science+Business Media New York.
News Article | February 23, 2017
As much as we try to avoid it, we are constantly sharing germs with those around us. But even when two people have the same infection, the resulting illnesses can be dramatically different--mild for one person, severe or even life-threatening for the other. Now, new research from The Rockefeller University offers insights into how these differences arise. Jean-Laurent Casanova, head of St. Giles Laboratory of Human Genetics of Infectious Diseases and Howard Hughes Medical Institute Investigator, led a team of researchers to uncover how two different conditions--a genetic immunodeficiency and delayed acquired immunity--can combine to produce a life-threatening infection. In the research, published online on February 23 in Cell, Casanova and his team focused on the case of an otherwise healthy young girl who developed a life-threatening infection from a very common strain of bacterium. Most of us carry this microbe, known as Staphylococcus aureus, on our skin and in our nostrils. It can cause minor infections (often referred to as "staph infections"), but in some people, it results in severe disease. The young girl's illness was mysterious: she had no known risk factors that would lead her to develop the acute form of the disease, and none of her family members had contracted it. So Casanova and his team set out to define the underlying cause of her disease by searching her DNA for mutations that might make her more susceptible to staph disease. They quickly identified a likely culprit--a single letter substitution in the two copies of a gene that encodes for a protein known as TIRAP, used by specific immune cells to flag invading bacteria. In laboratory experiments, the researchers found that TIRAP is critical for cells in the immune system's first line of defense against invaders. These are cells that develop before we are born, with built-in recognition systems for a host of molecules that are frequently present on the surface of invaders. "We were sure this was the explanation for the severity of her staphylococcal disease," says Casanova. "We thought we had it all figured out." But things turned out to be more complicated. To test his hypothesis, Casanova decided to analyze the DNA of other members of the patient's family. They hadn't suffered from severe staph infections, so they should have had normal TIRAP genes. However, he found the opposite--all seven members of her family had the same mutation as the young patient. The researchers now had two questions instead of just one: Why did this child get the invasive disease? And why were the rest of her family seemingly immune, even though they shared her immune-compromising mutation? The answers lie in a second line of immune defense that is not encoded within our DNA at birth. These secondary defenses are dependent on cells that generate antibodies against foreign compounds. "This is not something we are born with, but instead it is resistance that we acquire over the course of our lifetime when we are exposed to new pathogens," Casanova explains. The researchers found that the patient lacked antibodies against a single molecule, known as LTA, but the levels were normal for all of her family members. LTA is present on the surface of staphylococcal bacteria, and normally it is recognized by immune cells in both lines of defense. The antibodies against LTA were able to restore the function of the patient's immune cells in culture systems, and the researchers went on to confirm their hypothesis using a mouse model of the disease. The results explain both why the patient developed life-threatening disease and why her family members didn't. "Her illness likely resulted from failures in both lines of immunity. In her family, the second layer of defense compensated for genetic defects in the first," explains Casanova. "More broadly, it offers insight into how two people with the same infection, and even the same DNA, can have very different illnesses."