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This study investigates HLA-DR expression on activated T cells and serum neopterin levels in Juvenile Dermatomyositis (JDM) children pre- and post-treatment. Sixty-nine JDM children (less than 18 years) were included. Elevated HLA-DR+ T cells (>7 %) were observed in 19 % of untreated cases. Post-treatment, mean HLA-DR+ T cells decreased from 5.1 to 2.9 (P < 0.001), and serum neopterin levels declined from 19.3 to 9.1 nmol/L (P < 0.0001). A positive correlation between serum neopterin and HLA-DR T cell percentage was observed (r = 0.39, P = 0.01). Intravenous steroid treatment exhibited a 47.4 % improvement in HLA-DR+ T cells and a 50.5 % reduction in serum neopterin levels, in contrast to 14.8 % and 34.1 % in the oral steroid group. In conclusion, treatment, particularly with IV steroids, significantly improved HLA-DR+ T cells percentage and neopterin levels. A correlation between HLA-DR+ T cells percentage and serum neopterin was noted in untreated JDM patients.
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It is theorized that dysregulated immune responses to infectious insults contribute to the development of pediatric B-ALL. In this context, our understanding of the immunomodulatory-mediator-induced signaling responses of leukemic blasts in pediatric B-ALL diagnostic samples is rather limited. Hence, in this study, we defined the signaling landscape of leukemic blasts, as well as normal mature B cells and T cells residing in diagnostic samples from 63 pediatric B-ALL patients. These samples were interrogated with a range of immunomodulatory-mediators within 24 h of collection, and phosflow analyses of downstream proximal signaling nodes were performed. Our data reveal evidence of basal hyperphosphorylation across a broad swath of these signaling nodes in leukemic blasts in contrast to normal mature B cells and T cells in the same sample. We also detected similarities in the phosphoprotein signature between blasts and mature B cells in response to IFNγ and IL-2 treatment, but significant divergence in the phosphoprotein signature was observed between blasts and mature B cells in response to IL-4, IL-7, IL-10, IL-21 and CD40 ligand treatment. Our results demonstrate the existence of both symmetry and asymmetry in the phosphoprotein signature between leukemic and non-leukemic cells in pediatric B-ALL diagnostic samples.
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It is indeed a privilege to be an immunologist in what is arguably the golden age of immunology. From astounding advances in fundamental knowledge to groundbreaking immunotherapeutic offerings, immunology has carved out an enviable niche for itself in basic science and clinical medicine. The need and the vital importance of appropriate education, training, and certification in clinical immunology was recognized by the World Health Organization as far back as 1972. In the United States, Ph.D. scientists with board certification in medical laboratory immunology have served as directors of high-complexity Clinical Laboratory Improvement Amendments- and College of American Pathologists-certified clinical immunology laboratories since 1977. From 1977 to 2017, board certification for medical laboratory immunology was administered by the American Society for Microbiology through the American Board of Medical Laboratory Immunology examination. The American Board of Medical Laboratory Immunology examination was phased out in 2017, and in the fall of 2019, the American Society for Clinical Pathology (ASCP) Board of Certification (BOC) examination committee took on the responsibility of developing a new doctoral-level certification examination for medical laboratory immunology. This transition to the ASCP BOC represents a well-deserved and much-needed recognition of the rapid advances in and the highly specialized nature of medical laboratory immunology and its ever-increasing relevance to patient care. This new ASCP BOC certification is called the Diplomate in Medical Laboratory Immunology, and, as of April 1, 2023, it is now available to potential examinees. In this report, we describe the examination, eligibility routes, and potential career pathways for successful diplomates.
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Certificación , Laboratorios , HumanosRESUMEN
We present a unique and unusual case of a male patient diagnosed with two coexisting and typically unassociated X-linked conditions: he was initially diagnosed with X-linked agammaglobulinemia (XLA) followed by a diagnosis of X-linked chronic granulomatous disease (XCGD) and an as of yet unpublished hypomorphic gp91phox variant in the CYBB gene. The latter was tested after the finding of granulomatous gingivitis. Hematopoietic stem cell transplant (HSCT) was performed due to severe colitis and nodular regenerative hyperplasia (NRH) of the liver. Following transplant, complete donor engraftment was observed with the restoration of a normal oxidative burst and full restoration of normal levels of circulating, mature CD19+ B cells. This case is singular in that it does not involve a contiguous gene syndrome in which deleted genes are in close proximity to either BTK and CYBB, which has been previously reported. To our knowledge, this is the first reported case of XLA and XCGD co-existing in a single patient and of having both inborn errors of immunity successfully treated by HSCT.
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B cells and antibodies are indispensable for host immunity. Our understanding of the mechanistic processes that underpin how B cells operate has left an indelible mark on the field of clinical pathology, and recently has also dramatically reshaped the therapeutic landscape of diseases that were once considered incurable. Evaluating patients with primary immunodeficiency diseases (PID)/inborn errors of immunity (IEI) that primarily affect B cells, offers us an opportunity to further our understanding of how B cells develop, mature, function and, in certain instances, cause further disease. In this review we provide a brief compendium of IEI that principally affect B cells at defined stages of their developmental pathway, and also attempt to offer some educated viewpoints on how the management of these disorders could evolve over the years.
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Linfocitos B , Síndromes de Inmunodeficiencia , HumanosRESUMEN
Background: Host-pathogen dynamics associated with HIV infection are quite distinct in children versus adults. We interrogated the functional fitness of the lymphocyte responses in two cohorts of perinatally infected HIV+ pediatric subjects with early anti-retroviral therapy (ART) initiation but divergent patterns of virologic control. We hypothesized that sub-optimal viral control would compromise immune functional fitness. Methods: The immune responses in the two HIV+ cohorts (n = 6 in each cohort) were benchmarked against the responses measured in age-range matched, uninfected healthy control subjects (n = 11) by utilizing tests for normality, and comparison [the Kruskal-Wallis test, and the two-tailed Mann-Whitney U test (where appropriate)]. Lymphocyte responses were examined by intra-cellular cytokine secretion, degranulation assays as well as phosflow. A subset of these data were further queried by an automated clustering algorithm. Finally, we evaluated the humoral immune responses to four childhood vaccines in all three cohorts. Results: We demonstrate that contrary to expectations pediatric HIV+ patients with sub-optimal viral control display no significant deficits in immune functional fitness. In fact, the patients that display better virologic control lack functional Gag-specific T cell responses and compared to healthy controls they display signaling deficits and an enrichment of mitogen-stimulated CD3 negative and positive lymphocyte clusters with suppressed cytokine production. Conclusions: These results highlight the immune resilience in HIV+ children on ART with sub-optimal viral control. With respect to HIV+ children on ART with better viral control, our data suggest that this cohort might potentially benefit from targeted interventions that might mitigate cell-mediated immune functional quiescence.
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Immunologic responses during sepsis vary significantly among patients and evolve over the course of illness. Sepsis has a direct impact on the immune system due to adverse alteration of the production, maturation, function, and apoptosis of immune cells. Dysregulation in both the innate and adaptive immune responses during sepsis leads to a range of phenotypes consisting of both hyperinflammation and immunosuppression that can result in immunoparalysis. In this review, we discuss components of immune dysregulation in sepsis, biomarkers and functional immune assays to aid in immunophenotyping patients, and evolving immunomodulatory therapies. Important research gaps for the future include: (1) Defining how age, host factors including prior exposures, and genetics impact the trajectory of sepsis in children, (2) Developing tools for rapid assessment of immune function in sepsis, and (3) Assessing how evolving pediatric sepsis endotypes respond differently to immunomodulation. Although multiple promising immunomodulatory agents exist or are in development, access to rapid immunophenotyping will be needed to identify which children are most likely to benefit from which therapy. Advancements in the ability to perform multidimensional endotyping will be key to developing a personalized approach to children with sepsis. IMPACT: Immunologic responses during sepsis vary significantly among patients and evolve over the course of illness. The resulting spectrum of immunoparalysis that can occur due to sepsis can increase morbidity and mortality in children and adults. This narrative review summarizes the current literature surrounding biomarkers and functional immunologic assays for immune dysregulation in sepsis, with a focus on immunomodulatory therapies that have been evaluated in sepsis. A precision approach toward diagnostic endotyping and therapeutics, including gene expression, will allow for optimal clinical trials to evaluate the efficacy of individualized and targeted treatments for pediatric sepsis.
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Sepsis/inmunología , Biomarcadores/metabolismo , Niño , Humanos , Factores Inmunológicos/uso terapéutico , Sepsis/tratamiento farmacológicoRESUMEN
Heterophile antibody assays have been used to aid the diagnosis of infectious mononucleosis caused by the Epstein-Barr virus. Seven commercially available assays currently widely utilized in clinical laboratories were compared in this study. Variable performance characteristics and assay times are observed, and these pieces of data may assist clinical laboratories in assay selection and result interpretation.
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Anticuerpos Heterófilos/sangre , Anticuerpos Antivirales/sangre , Técnicas de Laboratorio Clínico/normas , Infecciones por Virus de Epstein-Barr/diagnóstico , Mononucleosis Infecciosa/diagnóstico , Mononucleosis Infecciosa/inmunología , Juego de Reactivos para Diagnóstico/normas , Adolescente , Anticuerpos Heterófilos/inmunología , Niño , Técnicas de Laboratorio Clínico/métodos , Infecciones por Virus de Epstein-Barr/sangre , Humanos , Inmunoglobulina M/sangre , Mononucleosis Infecciosa/sangre , Adulto JovenRESUMEN
The SARS-CoV-2 pandemic is an unprecedented epochal event on at least two fronts. Firstly, in terms of the rapid spread and the magnitude of the outbreak, and secondly, on account of the equally swift response of the scientific community that has galvanized itself into action and has successfully developed, tested and deployed highly effective and novel vaccines in record time to combat the virus. The sophistication and diversification of the scientific toolbox we now have at our disposal has enabled us to interrogate both the breadth and the depth of the immune response to a degree that is unparalleled in recent memory. In terms of our understanding of what is critical to contain the virus and mitigate the effects the pandemic, neutralizing antibodies to SARS-CoV-2 garner most of the attention, however, it is essential to recognize that it is the quality and the fitness of the virus-specific T cell and B cell response that lays the foundation and the backdrop for an effective neutralizing antibody response. In this report, we will review some of the key findings that have helped define and delineate some of the essential attributes of T and B cell responses in the setting of SARS-CoV-2 infection.
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Linfocitos B/inmunología , Linfocitos T CD4-Positivos/inmunología , Linfocitos T CD8-positivos/inmunología , COVID-19/inmunología , SARS-CoV-2/inmunología , Anticuerpos Neutralizantes/inmunología , Anticuerpos Antivirales/inmunología , Linfocitos B/virología , Linfocitos T CD4-Positivos/virología , Linfocitos T CD8-positivos/virología , COVID-19/epidemiología , COVID-19/virología , Humanos , Memoria Inmunológica/inmunología , Pandemias , SARS-CoV-2/fisiologíaRESUMEN
SLAM-associated protein (SAP) is an adaptor molecule that facilitates critical effector functions in immune cells, and its deficiency causes X-linked lymphoproliferative disease type 1 in which effector responses directed against EBV are severely compromised. The primary objective of this study was to phenotypically and functionally characterize a rare, CD8 T cell-restricted bimodal SAP expression pattern observed in healthy, human donors with the widely used 1C9-SAP mAb clone. We initially observed this pattern during the clinical validation of our flow cytometry-based assay to diagnose X-linked lymphoproliferative disease type 1 in our laboratory. For this validation study, we used multiparameter flow cytometry to identify cytosolic SAP expression in lymphocyte subsets, and CD8 T cells from the donors displaying the rare SAP expression pattern mentioned above were separately further evaluated by intracellular cytokine and CD107a staining to examine polyfunctionality following PMA/ionomycin and HLA class I allele-restricted EBV peptide epitope-induced T cell activation. Our data revealed that SAP 1C9-hi CD8 T cells clearly displayed higher polyfunctional responses versus SAP 1C9-lo CD8 T cells following PMA/ionomycin stimulation. Furthermore, polyfunctional EBV-specific CD8 T cell responses segregated with the SAP 1C9-hi CD8 T cells and not the SAP 1C9-lo CD8 T cells. Additionally, and rather intriguingly, short- and long-term T cell stimulation selectively diminished the signal for the 1C9-hi subset. Overall, our data suggest that although rare, this unique SAP expression pattern merits further evaluation as it has the potential to provide some insight into fundamental processes as they might relate to host-pathogen dynamics.
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Anticuerpos Monoclonales de Origen Murino/inmunología , Linfocitos T CD8-positivos/inmunología , Fenotipo , Proteína Asociada a la Molécula de Señalización de la Activación Linfocitaria/inmunología , Proteína Asociada a la Molécula de Señalización de la Activación Linfocitaria/metabolismo , Adulto , Donantes de Sangre , Células Cultivadas , Epítopos de Linfocito T/inmunología , Epítopos de Linfocito T/farmacología , Infecciones por Virus de Epstein-Barr/inmunología , Infecciones por Virus de Epstein-Barr/virología , Femenino , Citometría de Flujo , Herpesvirus Humano 4/inmunología , Interacciones Huésped-Patógeno/inmunología , Humanos , Inmunoglobulina G/inmunología , Ionomicina/farmacología , Activación de Linfocitos/efectos de los fármacos , Activación de Linfocitos/inmunología , Masculino , Transducción de Señal/efectos de los fármacos , Transducción de Señal/inmunología , Acetato de Tetradecanoilforbol/farmacologíaRESUMEN
Severe combined immunodeficiency (SCID) disorders compromise lymphocyte numbers and/or function. One subset of SCID typically affects T cell and Natural Killer (NK) cell development in tandem (T-B+NK-) due to mutations arising in the genes encoding the common γ chain or Janus Kinase 3 (JAK3). In rare circumstances, mutations in the JAK3 gene have been reported to cause atypical SCID that selectively affects T cells (T-B+NK+). Here we describe a case involving a female infant who was referred to our institution on day nine of life following an abnormal newborn screen result for T-SCID. Immunological assessments revealed a T-B+NK+ phenotype and molecular analyses, including whole exome sequencing, identified compound heterozygous JAK3 variants (R117C and E658K). Pre-transplant phosflow analyses revealed a persistent IL-7 signaling defect, based on phospho-STAT5 measurements, only in CD8 but not CD4 T cells. Intriguingly, phospho-STAT5 signals in response to IL-2 stimulation were not affected in either CD4 or CD8 T cells. The pre-transplant clinical course was unremarkable, and the patient received a cord-blood stem cell transplant on day 716 of life. Post-transplant monitoring revealed that despite normalization of lymphocyte counts, the CD8 T cell-restricted IL-7 signaling defect was still evident at day 627 post-transplant (phospho-STAT5 signal in CD8 T cells was > 60% reduced compared with CD4 T cells). The post-transplant clinical course has also been complicated by identification of autoimmune responses and likely GVHD-induced ichthyosis. To the best of our knowledge, this report represents the third case of JAK3-associated atypical SCID reported in the literature.
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Linfocitos T CD8-positivos/inmunología , Trasplante de Células Madre de Sangre del Cordón Umbilical , Interleucina-7/metabolismo , Janus Quinasa 3/genética , Mutación/genética , Inmunodeficiencia Combinada Grave/diagnóstico , Femenino , Humanos , Lactante , Recién Nacido , Fenotipo , Fosforilación , Factor de Transcripción STAT5/metabolismo , Inmunodeficiencia Combinada Grave/genética , Inmunodeficiencia Combinada Grave/terapia , Transducción de Señal , Secuenciación del ExomaAsunto(s)
Linfocitos T CD4-Positivos/inmunología , Linfocitos T CD4-Positivos/metabolismo , Estudios de Asociación Genética , Predisposición Genética a la Enfermedad , Interleucina-2/metabolismo , Receptores de Interferón/deficiencia , Transducción de Señal , Biomarcadores , Femenino , Humanos , Inmunofenotipificación , Lactante , Recuento de Linfocitos , Subgrupos Linfocitarios/inmunología , Subgrupos Linfocitarios/metabolismo , Fenotipo , Análisis de Secuencia de ADN , Receptor de Interferón gammaRESUMEN
BACKGROUND: The robust generation of human hematopoietic progenitor cells from induced or embryonic pluripotent stem cells would be beneficial for multiple areas of research, including mechanistic studies of hematopoiesis, the development of cellular therapies for autoimmune diseases, induced transplant tolerance, anticancer immunotherapies, disease modeling, and drug/toxicity screening. Over the past years, significant progress has been made in identifying effective protocols for hematopoietic differentiation from pluripotent stem cells and understanding stages of mesodermal, endothelial, and hematopoietic specification. Thus, it has been shown that variations in cytokine and inhibitory molecule treatments in the first few days of hematopoietic differentiation define primitive versus definitive potential of produced hematopoietic progenitor cells. The majority of current feeder-free, defined systems for hematopoietic induction from pluripotent stem cells include prolonged incubations with various cytokines that make the differentiation process complex and time consuming. We established that the application of Wnt agonist CHIR99021 efficiently promotes differentiation of human pluripotent stem cells in the absence of any hematopoietic cytokines to the stage of hemogenic endothelium capable of definitive hematopoiesis. METHODS: The hemogenic endothelium differentiation was accomplished in an adherent, serum-free culture system by applying CHIR99021. Hemogenic endothelium progenitor cells were isolated on day 5 of differentiation and evaluated for their endothelial, myeloid, and lymphoid potential. RESULTS: Monolayer induction based on GSK3 inhibition, described here, yielded a large number of CD31+CD34+ hemogenic endothelium cells. When isolated and propagated in adherent conditions, these progenitors gave rise to mature endothelium. When further cocultured with OP9 mouse stromal cells, these progenitors gave rise to various cells of myeloid lineages as well as natural killer lymphoid, T-lymphoid, and B-lymphoid cells. CONCLUSION: The results of this study substantiate a method that significantly reduces the complexity of current protocols for hematopoietic induction, offers a defined system to study the factors that affect the early stages of hematopoiesis, and provides a new route of lymphoid and myeloid cell derivation from human pluripotent stem cells, thus enhancing their use in translational medicine.
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Células Endoteliales/efectos de los fármacos , Células Madre Hematopoyéticas/efectos de los fármacos , Células Madre Pluripotentes/efectos de los fármacos , Inhibidores de Proteínas Quinasas/farmacología , Piridinas/farmacología , Pirimidinas/farmacología , Animales , Linfocitos B/citología , Linfocitos B/efectos de los fármacos , Linfocitos B/inmunología , Adhesión Celular/efectos de los fármacos , Diferenciación Celular/efectos de los fármacos , Técnicas de Cocultivo , Medio de Cultivo Libre de Suero/química , Medio de Cultivo Libre de Suero/farmacología , Células Endoteliales/citología , Células Endoteliales/inmunología , Glucógeno Sintasa Quinasa 3/antagonistas & inhibidores , Glucógeno Sintasa Quinasa 3/genética , Glucógeno Sintasa Quinasa 3/metabolismo , Hematopoyesis/genética , Células Madre Hematopoyéticas/citología , Células Madre Hematopoyéticas/inmunología , Humanos , Ratones , Células Madre Pluripotentes/citología , Células Madre Pluripotentes/inmunología , Linfocitos T/citología , Linfocitos T/efectos de los fármacos , Linfocitos T/inmunologíaRESUMEN
BACKGROUND: Chronic granulomatous disease (CGD) is an uncommon primary immunodeficiency that can be inherited in an X-linked (XL) or an autosomal recessive (AR) manner. We reviewed our large, single-center US experience with CGD. METHODS: We reviewed 27 patients at Ann & Robert H. Lurie Children's Hospital of Chicago from March 1985 to November 2013. Fisher exact test was used to compare differences in categorical variables, and Student t test was used to compare means for continuous variables. Serious infections were defined as those requiring intravenous antibiotics or hospitalization. RESULTS: There were 23 males and 4 females; 19 were XL and 8 were AR. The average age at diagnosis was 3.0 years; 2.1 years for XL and 5.3 years for AR inheritance (P = 0.02). There were 128 serious infections. The most frequent infectious agents were Staphylococcus aureus (n = 13), Serratia (n = 11), Klebsiella (n = 7), Aspergillus (n = 6) and Burkholderia (n = 4). The most common serious infections were pneumonia (n = 38), abscess (n = 32) and lymphadenitis (n = 29). Thirteen patients had granulomatous complications. Five patients were below the 5th percentile for height and 4 were below the 5th percentile for weight. Average length of follow-up after diagnosis was 10.1 years. Twenty-four patients were compliant and maintained on interferon-γ, trimethoprim-sulfamethoxazole and an azole. The serious infection rate was 0.62 per patient-year. Twenty-three patients are alive (1 was lost to follow-up). CONCLUSIONS: We present a large, single-center US experience with CGD. Twenty-three of 27 patients are alive after 3276 patient-months of follow-up (1 has been lost to follow-up), and our serious infection rate was 0.62 per patient-year.
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Enfermedad Granulomatosa Crónica , Adolescente , Adulto , Niño , Preescolar , Femenino , Enfermedad Granulomatosa Crónica/diagnóstico , Enfermedad Granulomatosa Crónica/genética , Enfermedad Granulomatosa Crónica/mortalidad , Enfermedad Granulomatosa Crónica/terapia , Humanos , Lactante , Estimación de Kaplan-Meier , Masculino , Estudios Retrospectivos , Adulto JovenAsunto(s)
Trasplante de Células , Subunidad gamma Común de Receptores de Interleucina/genética , Mutación , Transducción de Señal , Linfocitos T/metabolismo , Linfocitos T/trasplante , Adulto , Niño , Femenino , Humanos , Inmunofenotipificación , Lactante , Masculino , Fenotipo , Linfocitos T/inmunologíaRESUMEN
OBJECTIVES: Clinical laboratory immunology affects practically every aspect of medicine. Accordingly, appropriately trained, board-certified clinical laboratory immunologists are key contributors to the diagnosis and management of patients with various immune-mediated conditions. This review highlights the availability of postdoctoral level training programs for clinical laboratory immunology and identifies possible career tracks. METHODS: Fundamental elements for doctoral level clinical laboratory immunologists are identified and the critical components of diagnostic immunology training as well as career opportunities in and out of academia are described. RESULTS: Relative to other disciplines in laboratory medicine, little emphasis has been given to clinical laboratory immunology in medical, graduate, and postgraduate training. Formal postgraduate fellowship programs and board certification examinations are available, yet there remains a significant lack of awareness in the medical education community about the value and necessity of training in this field. CONCLUSIONS: It is anticipated that sharing this knowledge will increase awareness of the discipline of clinical laboratory immunology at the postdoctoral level with implications for the practice of laboratory medicine.
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Alergia e Inmunología/educación , Certificación , Educación de Postgrado en Medicina , Laboratorios , Ciencia del Laboratorio Clínico/educación , Servicios de Laboratorio Clínico/normas , Curriculum , Humanos , Técnicas InmunológicasRESUMEN
OBJECTIVES: Recent reports have provided conflicting evidence on the stability of CCR3 expression on the surface of basophils. Hence we wanted to independently evaluate the diagnostic usefulness of CCR3 as a surrogate marker of basophil activation and function. METHODS: We examined the correlative relationship between CCR3 expression on the surface of donor basophils and histamine release after donor basophils were treated with agonistic antibodies directed against the high-affinity IgE-Fc receptor and serum samples from 80 individuals displaying symptoms of chronic urticaria (CU). RESULTS: We observed that CCR3 was significantly downregulated on donor basophils treated with the agonistic antibody and CU-patient serum that demonstrated positive "histamine-releasing activity" (HRA scores >10). However, CCR3 downregulation was also observed on donor basophils incubated with more than 40% of CU-patient serum samples with HRA scores less than or equal to 10. CONCLUSIONS: Overall our data show that CCR3 demonstrates adequate sensitivity (83%) but weak specificity (59%) in its ability to reliably identify histamine-releasing activated basophils.
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Basófilos/metabolismo , Liberación de Histamina/inmunología , Histamina/metabolismo , Receptores CCR3/metabolismo , Receptores de IgE/metabolismo , Basófilos/inmunología , Biomarcadores/metabolismo , Regulación hacia Abajo , Humanos , Receptores Fc/inmunología , Receptores de IgE/inmunología , Sensibilidad y EspecificidadRESUMEN
Primary and secondary (boosted) memory CD8 T cells exhibit differences in gene expression, phenotype and function. The impact of repeated antigen stimulations on memory CD4 T cells is largely unknown. To address this issue, we utilized LCMV and Listeria monocytogenes infection of mice to characterize primary and secondary antigen (Ag)-specific Th1 CD4 T cell responses. Ag-specific primary memory CD4 T cells display a CD62L(lo)CCR7(hi) CD27(hi) CD127(hi) phenotype and are polyfunctional (most produce IFNγ, TNFα and IL-2). Following homologous prime-boost immunization we observed pathogen-specific differences in the rate of CD62L and CCR7 upregulation on memory CD4 T cells as well as in IL-2+IFNγco-production by secondary effectors. Phenotypic and functional plasticity of memory Th1 cells was observed following heterologous prime-boost immunization, wherein secondary memory CD4 T cells acquired phenotypic and functional characteristics dictated by the boosting agent rather than the primary immunizing agent. Our data also demonstrate that secondary memory Th1 cells accelerated neutralizing Ab formation in response to LCMV infection, suggesting enhanced capacity of this population to provide quality help for antibody production. Collectively these data have important implications for prime-boost vaccination strategies that seek to enhance protective immune responses mediated by Th1 CD4 T cell responses.
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Antígenos/inmunología , Memoria Inmunológica , Células TH1/inmunología , Células TH1/patología , Animales , Anticuerpos Neutralizantes/inmunología , Biomarcadores/metabolismo , Proliferación Celular , Homeostasis/inmunología , Inmunización Secundaria , Interleucina-2/biosíntesis , Cinética , Listeria monocytogenes/inmunología , Listeriosis/inmunología , Listeriosis/patología , Coriomeningitis Linfocítica/inmunología , Coriomeningitis Linfocítica/patología , Virus de la Coriomeningitis Linfocítica/inmunología , Ratones , Ratones Endogámicos C57BL , Pruebas de Neutralización , FenotipoRESUMEN
After infection or vaccination, antigen-specific T cells proliferate then contract in numbers to a memory set point. T-cell contraction is observed after both acute and prolonged infections although it is unknown if contraction is regulated similarly in both scenarios. Here, we show that contraction of antigen-specific CD8(+) and CD4(+) T cells is markedly reduced in TNF/perforin-double deficient (DKO) mice responding to attenuated Listeria monocytogenes infection. Reduced contraction in DKO mice was associated with delayed clearance of infection and sustained T-cell proliferation during the normal contraction interval. Mechanistically, sustained T-cell proliferation mapped to prolonged infection in the absence of TNF; however, reduced contraction required the additional absence of perforin since T cells in mice lacking either TNF or perforin (singly deficient) underwent normal contraction. Thus, while T-cell contraction after acute infection is independent of peforin, a perforin-dependent pathway plays a previously unappreciated role to mediate contraction of antigen-specific CD8(+) and CD4(+) T cells during prolonged L. monocytogenes infection.