RESUMEN
BACKGROUND: Elevated TCRαß+CD4-CD8- double-negative T cells (DNT) and serum biomarkers help identify FAS mutant patients with autoimmune lymphoproliferative syndrome (ALPS). However, in some patients with clinical features and biomarkers consistent with ALPS, germline or somatic FAS mutations cannot be identified on standard exon sequencing (ALPS-undetermined: ALPS-U). OBJECTIVE: We sought to explore whether complex genetic alterations in the FAS gene escaping standard sequencing or mutations in other FAS pathway-related genes could explain these cases. METHODS: Genetic analysis included whole FAS gene sequencing, copy number variation analysis, and sequencing of FAS cDNA and other FAS pathway-related genes. It was guided by FAS expression analysis on CD57+DNT, which can predict somatic loss of heterozygosity (sLOH). RESULTS: Nine of 16 patients with ALPS-U lacked FAS expression on CD57+DNT predicting heterozygous "loss-of-expression" FAS mutations plus acquired somatic second hits in the FAS gene, enriched in DNT. Indeed, 7 of 9 analyzed patients carried deep intronic mutations or large deletions in the FAS gene combined with sLOH detectable in DNT; 1 patient showed a FAS exon duplication. Three patients had reduced FAS expression, and 2 of them harbored mutations in the FAS promoter, which reduced FAS expression in reporter assays. Three of the 4 ALPS-U patients with normal FAS expression carried heterozygous FADD mutations with sLOH. CONCLUSION: A combination of serum biomarkers and DNT phenotyping is an accurate means to identify patients with ALPS who are missed by routine exome sequencing.
Asunto(s)
Síndrome Linfoproliferativo Autoinmune , Receptor fas , Humanos , Síndrome Linfoproliferativo Autoinmune/diagnóstico , Síndrome Linfoproliferativo Autoinmune/genética , Biomarcadores , Variaciones en el Número de Copia de ADN , Secuenciación del Exoma , Receptor fas/genética , Proteína de Dominio de Muerte Asociada a Fas/genética , MutaciónRESUMEN
BACKGROUND: Fas ligand (FasL) is expressed by activated T cells and induces death in target cells upon binding to Fas. Loss-of-function FAS or FASLG mutations cause autoimmune-lymphoproliferative syndrome (ALPS) characterized by expanded double-negative T cells (DNT) and elevated serum biomarkers. While most ALPS patients carry heterozygous FAS mutations, FASLG mutations are rare and usually biallelic. Only 2 heterozygous variants were reported, associated with an atypical clinical phenotype. OBJECTIVE: We revisited the significance of heterozygous FASLG mutations as a cause of ALPS. METHODS: Clinical features and biomarkers were analyzed in 24 individuals with homozygous or heterozygous FASLG variants predicted to be deleterious. Cytotoxicity assays were performed with patient T cells and biochemical assays with recombinant FasL. RESULTS: Homozygous FASLG variants abrogated cytotoxicity and resulted in early-onset severe ALPS with elevated DNT, raised vitamin B12, and usually no soluble FasL. In contrast, heterozygous variants affected FasL function by reducing expression, impairing trimerization, or preventing Fas binding. However, they were not associated with elevated DNT and vitamin B12, and they did not affect FasL-mediated cytotoxicity. The dominant-negative effects of previously published variants could not be confirmed. Even Y166C, causing loss of Fas binding with a dominant-negative effect in biochemical assays, did not impair cellular cytotoxicity or cause vitamin B12 and DNT elevation. CONCLUSION: Heterozygous loss-of-function mutations are better tolerated for FASLG than for FAS, which may explain the low frequency of ALPS-FASLG.
Asunto(s)
Síndrome Linfoproliferativo Autoinmune , Humanos , Síndrome Linfoproliferativo Autoinmune/genética , Proteína Ligando Fas/genética , Mutación , Biomarcadores , Vitaminas , Receptor fas/genética , Apoptosis/genéticaRESUMEN
Hemophagocytic lymphohistiocytosis (HLH) is a disorder of uncontrolled immune activation with distinct clinical features including fever, cytopenia, splenomegaly, and sepsis-like symptoms. In a young adolescent patient a novel germline GATA2 variant (NM_032638.5 (GATA2): c.177C>G, p.Tyr59Ter) was discovered and had resulted in non-tuberculous mycobacterial (NTM) infection and aggressive HLH. Strikingly, impaired degranulation of cytotoxic T-lymphocytes (CTL) and natural killer (NK)-cells was detected in CD107a-analyses. The affected patient was treated with HLA-matched unrelated alloHSCT, and subsequently all hematologic and infectious abnormalities including HLH and NTM resolved. This case supports early alloHSCT in GATA2 deficiencies as curative approach regardless of active NTM infection. Future studies on GATA2 c.177C>G, p.Tyr59*Ter might unravel its potential role in cytotoxic effector cell function and its contribution to HLH pathogenesis.
Asunto(s)
Factor de Transcripción GATA2/genética , Predisposición Genética a la Enfermedad , Variación Genética , Linfohistiocitosis Hemofagocítica/diagnóstico , Linfohistiocitosis Hemofagocítica/genética , Infecciones por Mycobacterium no Tuberculosas/diagnóstico , Infecciones por Mycobacterium no Tuberculosas/genética , Biomarcadores , Manejo de la Enfermedad , Femenino , Estudios de Asociación Genética , Trasplante de Células Madre Hematopoyéticas , Humanos , Inmunofenotipificación , Células Asesinas Naturales/inmunología , Células Asesinas Naturales/metabolismo , Linfohistiocitosis Hemofagocítica/terapia , Masculino , Infecciones por Mycobacterium no Tuberculosas/terapia , Tomografía Computarizada por Tomografía de Emisión de Positrones , Resultado del TratamientoRESUMEN
The identification and characterization of rare immune cell populations in humans can be facilitated by their growth advantage in the context of specific genetic diseases. Here, we use autoimmune lymphoproliferative syndrome to identify a population of FAS-controlled TCRαß+ T cells. They include CD4+, CD8+, and double-negative T cells and can be defined by a CD38+CD45RA+T-BET- expression pattern. These unconventional T cells are present in healthy individuals, are generated before birth, are enriched in lymphoid tissue, and do not expand during acute viral infection. They are characterized by a unique molecular signature that is unambiguously different from other known T cell differentiation subsets and independent of CD4 or CD8 expression. Functionally, FAS-controlled T cells represent highly proliferative, noncytotoxic T cells with an IL-10 cytokine bias. Mechanistically, regulation of this physiological population is mediated by FAS and CTLA4 signaling, and its survival is enhanced by mTOR and STAT3 signals. Genetic alterations in these pathways result in expansion of FAS-controlled T cells, which can cause significant lymphoproliferative disease.
Asunto(s)
ADP-Ribosil Ciclasa 1/inmunología , Linfocitos T CD4-Positivos/inmunología , Linfocitos T CD8-positivos/inmunología , Antígenos Comunes de Leucocito/metabolismo , Receptor fas/inmunología , Adolescente , Adulto , Anciano , Niño , Preescolar , Femenino , Humanos , Lactante , Recién Nacido , Activación de Linfocitos/inmunología , Trastornos Linfoproliferativos/inmunología , Masculino , Persona de Mediana Edad , Transducción de Señal/inmunología , Adulto JovenRESUMEN
In relapsed and refractory multiple myeloma (MM), adoptive cell therapies (ACT) including CAR-T-cells are under clinical investigation. However, relapse due to T-cell exhaustion or limited persistence is an obstacle. Before ACT are considered in MM, high-dose (HD) melphalan followed by autologous stem-cell transplantation (autoSCT) has been administered in most clinical situations. Yet, the impact of HD chemotherapy on T-cells in MM with respect to ACT is unclear. In this study, T-lymphocytes' phenotypes, expansion properties, lentiviral transduction efficacy, and gene expression were examined with special respect to patients following HD melphalan. Significant impairment of T-cells' expansion and transduction rates could be demonstrated. Expansion was diminished due to inherent disadvantages of the predominant T-cell phenotype but restored over time. The quantitative fraction of CD27-/CD28- T-cells before expansion was predictive of T-cell yield. Following autoSCT, the transduction efficacy was reduced by disturbed lentiviral genome integration. Moreover, an unfavorable T-cell phenotype after expansion was demonstrated. In initial analyses of CD107a degranulation impaired T-cell cytotoxicity was detected in one patient following melphalan and autoSCT. The findings of our study have potential implications regarding the time point of leukapheresis for CAR-T-cell manufacturing. Our results point to a preferred interval of more than 3 months until patients should undergo cell separation for CAR-T therapy in the specific situation post-HD melphalan/autoSCT. Monitoring of CD27-/CD28- T-cells, has the potential to influence clinical decision making before apheresis in MM.
Asunto(s)
Citometría de Flujo , Inmunidad Innata , Síndromes de Inmunodeficiencia , Monocitos , Femenino , Humanos , Síndromes de Inmunodeficiencia/sangre , Síndromes de Inmunodeficiencia/diagnóstico , Síndromes de Inmunodeficiencia/inmunología , Síndromes de Inmunodeficiencia/patología , Masculino , Monocitos/inmunología , Monocitos/metabolismo , Monocitos/patologíaRESUMEN
Primary immunodeficiencies (PID) comprise a group of more than 300 mostly monogenetic disorders of the immune system leading to infection susceptibility and a variety of associated clinical and immunological complications. In a majority of these disorders the absence, disproportions or dysfunction of leucocyte subpopulations or of proteins expressed by these cells are observed. These distinctive features are studied by multicolour flow cytometry and the results are used for diagnosis, follow up, classification and therapy monitoring in patients with PIDs. Although a definite diagnosis almost always relies on genetic analysis in PIDs, the results of flow cytometric diagnostics are pivotal in the initial diagnostic assessment of suspected PID patients and often guide the treating physician to a more selective and efficient genetic diagnostic procedure, even in the era of next generation sequencing technology. Furthermore, phenotypic and functional flow cytometry tests allow to validate novel genetic variants and the mapping of complex disturbances of the immune system in individual patients in a personalized manner. In this review we give an overview on phenotypic, functional as well as disease/protein specific flow cytometric assays in the diagnosis of PID and highlight diagnostic strategies and specialties for several selected PIDs by way of example.
RESUMEN
Premature T-cell immunosenescence with CD57+ CD8+ T-cell accumulation has been linked to immunodeficiency and autoimmunity in primary immunodeficiencies including activated PI3 kinase delta syndrome (APDS). To address whether CD57 marks the typical senescent T-cell population seen in adult individuals or identifies a distinct population in APDS, we compared CD57+ CD8+ T cells from mostly pediatric APDS patients to those of healthy adults with similarly prominent senescent T cells. CD57+ CD8+ T cells from APDS patients were less differentiated with more CD27+ CD28+ effector memory T cells showing increased PD1 and Eomesodermin expression. In addition, transition of naïve to CD57+ CD8+ T cells was not associated with the characteristic telomere shortening. Nevertheless, they showed the increased interferon-gamma secretion, enhanced degranulation and reduced in vitro proliferation typical of senescent CD57+ CD8+ T cells. Thus, hyperactive PI3 kinase signaling favors premature accumulation of a CD57+ CD8+ T-cell population, which shows most functional features of typical senescent T cells, but is different in terms of differentiation and relative telomere shortening. Initial observations indicate that this specific differentiation state may offer the opportunity to revert premature T-cell immunosenescence and its potential contribution to inflammation and immunodeficiency in APDS.
Asunto(s)
Antígenos CD57/metabolismo , Diferenciación Celular , Síndromes de Inmunodeficiencia/etiología , Síndromes de Inmunodeficiencia/metabolismo , Fosfatidilinositol 3-Quinasas/metabolismo , Subgrupos de Linfocitos T/inmunología , Subgrupos de Linfocitos T/metabolismo , Acortamiento del Telómero , Diferenciación Celular/genética , Diferenciación Celular/inmunología , Senescencia Celular/genética , Senescencia Celular/inmunología , Fosfatidilinositol 3-Quinasa Clase I/metabolismo , Citocinas/metabolismo , Humanos , Inmunofenotipificación , Recuento de Linfocitos , Enfermedades de Inmunodeficiencia Primaria , Sirolimus/farmacología , Subgrupos de Linfocitos T/efectos de los fármacosRESUMEN
We report our experience in using flow cytometry-based immunological screening prospectively as a decision tool for the use of genetic studies in the diagnostic approach to patients with hemophagocytic lymphohistiocytosis (HLH). We restricted genetic analysis largely to patients with abnormal immunological screening, but included whole exome sequencing (WES) for those with normal findings upon Sanger sequencing. Among 290 children with suspected HLH analyzed between 2010 and 2014 (including 17 affected, but asymptomatic siblings), 87/162 patients with "full" HLH and 79/111 patients with "incomplete/atypical" HLH had normal immunological screening results. In 10 patients, degranulation could not be tested. Among the 166 patients with normal screening, genetic analysis was not performed in 107 (all with uneventful follow-up), while 154 single gene tests by Sanger sequencing in the remaining 59 patients only identified a single atypical CHS patient. Flow cytometry correctly predicted all 29 patients with FHL-2, XLP1 or 2. Among 85 patients with defective NK degranulation (including 13 asymptomatic siblings), 70 were Sanger sequenced resulting in a genetic diagnosis in 55 (79%). Eight patients underwent WES, revealing mutations in two known and one unknown cytotoxicity genes and one metabolic disease. FHL3 was the most frequent genetic diagnosis. Immunological screening provided an excellent decision tool for the need and depth of genetic analysis of HLH patients and provided functionally relevant information for rapid patient classification, contributing to a significant reduction in the time from diagnosis to transplantation in recent years.
Asunto(s)
Péptidos y Proteínas de Señalización Intracelular/genética , Células Asesinas Naturales/inmunología , Proteínas con Dominio LIM/genética , Proteínas con Homeodominio LIM/genética , Linfohistiocitosis Hemofagocítica/diagnóstico , Proteínas Musculares/genética , Factores de Transcripción/genética , Enfermedades Asintomáticas , Degranulación de la Célula , Niño , Citometría de Flujo , Pruebas Genéticas , Humanos , Péptidos y Proteínas de Señalización Intracelular/metabolismo , Proteínas con Dominio LIM/metabolismo , Proteínas con Homeodominio LIM/metabolismo , Linfohistiocitosis Hemofagocítica/genética , Linfohistiocitosis Hemofagocítica/inmunología , Proteínas Musculares/metabolismo , Mutación/genética , Trasplante de Órganos , Guías de Práctica Clínica como Asunto , Pronóstico , Estudios Prospectivos , Hermanos , Factores de Transcripción/metabolismo , Secuenciación del ExomaRESUMEN
INTRODUCTION: Doppler sonography of the uterine artery (UA) is done to monitor pregnancies, because the detected flow patterns are useful to draw inferences about possible disorders of trophoblast invasion. Increased resistance in the UA is associated with an increased risk of preeclampsia and/or intrauterine growth restriction (IUGR) and perinatal mortality. In the absence of standardized figures, the normal ranges of the various available reference curves sometimes differ quite substantially from one another. The causes for this are differences in the flow patterns of the UA depending on the position of the pulsed Doppler gates as well as branching of the UA. Because of the discrepancies between the different reference curves and the practical problems this poses for guideline recommendations, we thought it would be useful to create our own reference curves for Doppler measurements of the UA obtained from a singleton cohort under standardized conditions. MATERIAL AND METHODS: This retrospective cohort study was carried out in the Department of Obstetrics of the Charité - Universitätsmedizin Berlin, the Department for Obstetrics and Prenatal Medicine of the University Hospital Halle (Saale) and the Center for Prenatal Diagnostics and Human Genetics Kurfürstendamm 199. Available datasets from the three study locations were identified and reference curves were generated using the LMS method. Measured values were correlated with age of gestation, and a cubic model and Box-Cox power transformation (L), the median (M) and the coefficient of variation (S) were used to smooth the curves. RESULTS: 103â720 Doppler examinations of the UA carried out in singleton pregnancies from the 11th week of gestation (10 + 1 GW) were analyzed. The mean pulsatility index (Mean PI) showed a continuous decline over the course of pregnancy, dropping to a plateau of around 0.84 between the 23rd and 27th GW, after which it decreased again. CONCLUSION: Age of gestation, placental position, position of pulsed Doppler gates and branching of the UA can all change the flow pattern. The mean pulsatility index (Mean PI) showed a continuous decrease over time. There were significant differences between our data and alternative reference curves. A system of classifying Doppler studies and a reference curve adapted to the current technology are urgently required to differentiate better between physiological and pathological findings.
RESUMEN
Hemophagocytic lymphohistiocytosis (HLH) is a life-threatening inflammatory syndrome characterized by hyperactivation of lymphocytes and histiocytes. T cells play a key role in HLH pathogenesis, but their differentiation pattern is not well characterized in patients with active HLH. We compared T-cell activation patterns between patients with familial HLH (1°HLH), 2°HLH without apparent infectious trigger (2°HLH) and 2°HLH induced by a viral infection (2°V-HLH). Polyclonal CD8+ T cells are highly activated in 1°HLH and 2°V-HLH, but less in 2°HLH as assessed by HLA-DR expression and marker combination with CD45RA, CCR7, CD127, PD-1 and CD57. Absence of increased HLA-DR expression on T cells excluded active 1° HLH with high sensitivity and specificity. A high proportion of polyclonal CD127- CD4+ T cells expressing HLA-DR, CD57, and perforin is a signature of infants with 1°HLH, much less prominent in virus-associated 2°HLH. The similar pattern and extent of CD8+ T-cell activation compared to 2° V-HLH is compatible with a viral trigger of 1°HLH. However, in most 1°HLH patients no triggering infection was documented and the unique activation of cytotoxic CD4+ T cells indicates that the overall T-cell response in 1°HLH is different. This may reflect different pathways of pathogenesis of these two HLH variants.
Asunto(s)
Linfocitos T CD8-positivos/inmunología , Linfohistiocitosis Hemofagocítica/inmunología , Virosis/inmunología , Antígenos CD57/metabolismo , Diferenciación Celular , Células Cultivadas , Femenino , Antígenos HLA-DR/metabolismo , Humanos , Lactante , Recién Nacido , Activación de Linfocitos , Linfohistiocitosis Hemofagocítica/diagnóstico , Linfohistiocitosis Hemofagocítica/etiología , Masculino , Perforina/metabolismo , Receptores de Antígenos de Linfocitos T/genética , Virosis/complicaciones , Virosis/diagnósticoAsunto(s)
Antibióticos Antineoplásicos/uso terapéutico , Síndrome Linfoproliferativo Autoinmune/tratamiento farmacológico , Inmunosupresores/uso terapéutico , Sirolimus/uso terapéutico , Receptor fas/genética , Adolescente , Síndrome Linfoproliferativo Autoinmune/genética , Síndrome Linfoproliferativo Autoinmune/inmunología , Síndrome Linfoproliferativo Autoinmune/patología , Biomarcadores/metabolismo , Niño , Preescolar , Progresión de la Enfermedad , Esquema de Medicación , Proteína Ligando Fas/genética , Proteína Ligando Fas/inmunología , Femenino , Regulación de la Expresión Génica , Humanos , Lactante , Recién Nacido , Interleucina-10/genética , Interleucina-10/inmunología , Linfadenopatía/tratamiento farmacológico , Linfadenopatía/genética , Linfadenopatía/inmunología , Linfadenopatía/patología , Masculino , Estudios Retrospectivos , Esplenomegalia/tratamiento farmacológico , Esplenomegalia/genética , Esplenomegalia/inmunología , Esplenomegalia/patología , Receptor fas/inmunologíaRESUMEN
Autoimmune lymphoproliferative syndrome (ALPS) is a human disorder characterized by defective Fas signaling, resulting in chronic benign lymphoproliferation and accumulation of TCRαß(+) CD4(-) CD8(-) double-negative T (DNT) cells. Although their phenotype resembles that of terminally differentiated or exhausted T cells, lack of KLRG1, high eomesodermin, and marginal T-bet expression point instead to a long-lived memory state with potent proliferative capacity. Here we show that despite their terminally differentiated phenotype, human ALPS DNT cells exhibit substantial mitotic activity in vivo. Notably, hyperproliferation of ALPS DNT cells is associated with increased basal and activation-induced phosphorylation of serine-threonine kinases Akt and mechanistic target of rapamycin (mTOR). The mTOR inhibitor rapamycin abrogated survival and proliferation of ALPS DNT cells, but not of CD4(+) or CD8(+) T cells in vitro. In vivo, mTOR inhibition reduced proliferation and abnormal differentiation by DNT cells. Importantly, increased mitotic activity and hyperactive mTOR signaling was also observed in recently defined CD4(+) or CD8(+) precursor DNT cells, and mTOR inhibition specifically reduced these cells in vivo, indicating abnormal programming of Fas-deficient T cells before the DNT stage. Thus, our results identify the mTOR pathway as a major regulator of lymphoproliferation and aberrant differentiation in ALPS.
Asunto(s)
Síndrome Linfoproliferativo Autoinmune/inmunología , Linfocitos T CD4-Positivos/inmunología , Linfocitos T CD8-positivos/inmunología , Diferenciación Celular/inmunología , Transducción de Señal/inmunología , Serina-Treonina Quinasas TOR/inmunología , Adolescente , Adulto , Síndrome Linfoproliferativo Autoinmune/patología , Linfocitos T CD4-Positivos/patología , Linfocitos T CD8-positivos/patología , Niño , Preescolar , Femenino , Humanos , Lectinas Tipo C/inmunología , Antígenos Comunes de Leucocito/inmunología , Masculino , Proteínas Proto-Oncogénicas c-akt/inmunología , Receptores de Antígenos de Linfocitos T/inmunología , Receptores Inmunológicos , Transactivadores/inmunologíaAsunto(s)
Síndrome Linfoproliferativo Autoinmune , Proteínas Sanguíneas , Síndrome de Plaquetas Grises , Proteínas del Tejido Nervioso , Receptores de Superficie Celular , Síndrome Linfoproliferativo Autoinmune/diagnóstico , Síndrome Linfoproliferativo Autoinmune/genética , Síndrome Linfoproliferativo Autoinmune/metabolismo , Síndrome Linfoproliferativo Autoinmune/patología , Proteínas Sanguíneas/genética , Proteínas Sanguíneas/metabolismo , Preescolar , Proteína Ligando Fas/genética , Proteína Ligando Fas/metabolismo , Femenino , Síndrome de Plaquetas Grises/diagnóstico , Síndrome de Plaquetas Grises/genética , Síndrome de Plaquetas Grises/metabolismo , Síndrome de Plaquetas Grises/patología , Humanos , Lactante , Masculino , Proteínas del Tejido Nervioso/genética , Proteínas del Tejido Nervioso/metabolismo , Receptores de Superficie Celular/genética , Receptores de Superficie Celular/metabolismo , Receptor fas/genética , Receptor fas/metabolismoRESUMEN
BACKGROUND: Most patients with MHC class I (MHC-I) deficiency carry genetic defects in transporter associated with antigen processing 1 (TAP1) or TAP2. The clinical presentation can vary, and about half of the patients have severe skin disease. Previously, one report described ß2-microglobulin (ß2m) deficiency as another monogenetic cause of MHC-I deficiency, but no further immunologic evaluation was performed. OBJECTIVE: We sought to describe the molecular and immunologic features of ß2m deficiency in 2 Turkish siblings with new diagnoses. METHODS: Based on clinical and serologic findings, the genetic defect was detected by means of candidate gene analysis. The immunologic characterization comprises flow cytometry, ELISA, functional assays, and immunohistochemistry. RESULTS: Here we provide the first extensive clinical and immunologic description of ß2m deficiency in 2 siblings. The sister had recurrent respiratory tract infections and severe skin disease, whereas the brother was fairly asymptomatic but had bronchiectasis. Not only polymorphic MHC-I but also the related CD1a, CD1b, CD1c, and neonatal Fc receptor molecules were absent from the surfaces of ß2m-deficient cells. Absent neonatal Fc receptor surface expression led to low serum IgG and albumin levels in both siblings, whereas the heterozygous parents had normal results for all tested parameters except ß2m mRNA (B2M) expression. Similar to TAP deficiency in the absence of a regular CD8 T-cell compartment, CD8(+) γδ T cells were strongly expanded. Natural killer cells were normal in number but not "licensed to kill." CONCLUSION: The clinical presentation of patients with ß2m deficiency resembles that of patients with other forms of MHC-I deficiency, but because of the missing stabilizing effect of ß2m on other members of the MHC-I family, the immunologic defect is more extensive than in patients with TAP deficiency.
Asunto(s)
Bronquiectasia/inmunología , Síndromes de Inmunodeficiencia/inmunología , Infecciones del Sistema Respiratorio/inmunología , Úlcera Cutánea/inmunología , Microglobulina beta-2/inmunología , Inmunidad Adaptativa , Adolescente , Adulto , Antígenos CD1/genética , Antígenos CD1/inmunología , Bronquiectasia/complicaciones , Bronquiectasia/genética , Bronquiectasia/patología , Linfocitos T CD8-positivos/inmunología , Linfocitos T CD8-positivos/patología , Consanguinidad , Femenino , Eliminación de Gen , Antígenos de Histocompatibilidad Clase I/genética , Antígenos de Histocompatibilidad Clase I/inmunología , Humanos , Inmunidad Innata , Inmunoglobulina G/sangre , Inmunoglobulina G/genética , Síndromes de Inmunodeficiencia/complicaciones , Síndromes de Inmunodeficiencia/genética , Síndromes de Inmunodeficiencia/patología , Células Asesinas Naturales/inmunología , Células Asesinas Naturales/patología , Masculino , Linaje , Isoformas de Proteínas/deficiencia , Isoformas de Proteínas/genética , Isoformas de Proteínas/inmunología , Receptores Fc/deficiencia , Receptores Fc/genética , Receptores Fc/inmunología , Recurrencia , Infecciones del Sistema Respiratorio/complicaciones , Infecciones del Sistema Respiratorio/genética , Infecciones del Sistema Respiratorio/patología , Hermanos , Úlcera Cutánea/complicaciones , Úlcera Cutánea/genética , Úlcera Cutánea/patología , Microglobulina beta-2/deficiencia , Microglobulina beta-2/genéticaRESUMEN
Familial hemophagocytic lymphohistiocytosis (FHL) is a genetically heterogeneous hyperinflammatory syndrome, caused by an uncontrolled and ineffective proliferation and activation of T-lymphocytes, NK-cells, and macrophages that infiltrate multiple organs. Herein, a patient is presented who suffered from hepatitis and atypical brain lesions. Genetic studies revealed a homozygous mutation in the STXP2 gene; and thus, the diagnosis of FHL5 was confirmed.
Asunto(s)
Linfohistiocitosis Hemofagocítica/genética , Proteínas Munc18/genética , Agammaglobulinemia/genética , Agammaglobulinemia/inmunología , Edad de Inicio , Encéfalo/patología , Niño , Resultado Fatal , Hepatitis Autoinmune/genética , Hepatitis Autoinmune/inmunología , Homocigoto , Humanos , Células Asesinas Naturales/inmunología , Linfohistiocitosis Hemofagocítica/diagnóstico , Linfohistiocitosis Hemofagocítica/inmunología , Imagen por Resonancia Magnética , Masculino , Mutación , Linfocitos T/inmunologíaRESUMEN
X-linked severe combined immunodeficiency (X-SCID) leads to a T(-) NK(-) B(+) immunophenotype and is caused by mutations in the gene encoding the IL-2 receptor γ-chain (IL2RG). IL2RG(R222C) leads to atypical SCID with a severe early onset phenotype despite largely normal NK- and T-cell numbers. To address this discrepancy, we performed a detailed analysis of T, B, and NK cells, including quantitative STAT phosphorylation and functional responses to the cytokines IL-2, IL-4, IL-15, and IL-21 in a patient with the IL2RG(R222C) mutation. Moreover, we identified nine additional unpublished patients with the same mutations, all with a full SCID phenotype, and confirmed selected immunological observations. T-cell development was variably affected, but led to borderline T-cell receptor excision circle (TREC) levels and a normal repertoire. T cells showed moderately reduced proliferation, failing enhancement by IL-2. While NK-cell development was normal, IL-2 enhancement of NK-cell degranulation and IL-15-induced cytokine production were absent. IL-2 or IL-21 failed to enhance B-cell proliferation and plasmablast differentiation. These functional alterations were reflected by a differential impact of IL2RG(R222C) on cytokine signal transduction, with a gradient IL-4Asunto(s)
Linfocitos B/inmunología
, Citocinas/inmunología
, Subunidad gamma Común de Receptores de Interleucina/genética
, Células Asesinas Naturales/inmunología
, Inmunodeficiencia Combinada Grave/inmunología
, Linfocitos T/inmunología
, Humanos
, Lactante
, Subunidad gamma Común de Receptores de Interleucina/inmunología
, Activación de Linfocitos/genética
, Activación de Linfocitos/inmunología
, Masculino
, Mutación
, Fenotipo
, Transducción de Señal/inmunología
RESUMEN
Accumulation of CD3(+) T-cell receptor (TCR)αß(+)CD4(-)CD8(-) double-negative T cells (DNT) is a hallmark of autoimmune lymphoproliferative syndrome (ALPS). DNT origin and differentiation pathways remain controversial. Here we show that human ALPS DNT have features of terminally differentiated effector memory T cells reexpressing CD45RA(+) (TEMRA), but are CD27(+)CD28(+)KLRG1(-) and do not express the transcription factor T-bet. This unique phenotype was also detected among CD4(+) or CD8(+) ALPS TEMRA cells. T-cell receptor ß deep sequencing revealed a significant fraction of shared CDR3 sequences between ALPS DNT and both CD4(+) and CD8(+)TEMRA cells. Moreover, in ALPS patients with a germ line FAS mutation and somatic loss of heterozygosity, in whom biallelic mutant cells can be tracked by absent Fas expression, Fas-negative T cells accumulated not only among DNT, but also among CD4(+) and CD8(+)TEMRA cells. These data indicate that in human Fas deficiency DNT cannot only derive from CD8(+), but also from CD4(+) T cells. Furthermore, defective Fas signaling leads to aberrant transcriptional programs and differentiation of subsets of CD4(+) and CD8(+) T cells. Accumulation of these cells before their double-negative state appears to be an important early event in the pathogenesis of lymphoproliferation in ALPS patients.
Asunto(s)
Síndrome Linfoproliferativo Autoinmune/inmunología , Síndrome Linfoproliferativo Autoinmune/patología , Linfocitos T CD4-Positivos/inmunología , Linfocitos T CD4-Positivos/patología , Linfocitos T CD8-positivos/inmunología , Linfocitos T CD8-positivos/patología , Subgrupos de Linfocitos T/inmunología , Subgrupos de Linfocitos T/patología , Receptor fas/deficiencia , Receptor fas/genética , Adolescente , Adulto , Síndrome Linfoproliferativo Autoinmune/genética , Linfocitos T CD4-Positivos/metabolismo , Linfocitos T CD8-positivos/metabolismo , Diferenciación Celular/genética , Diferenciación Celular/inmunología , Niño , Preescolar , Estudios de Asociación Genética , Mutación de Línea Germinal , Humanos , Memoria Inmunológica , Antígenos Comunes de Leucocito/metabolismo , Pérdida de Heterocigocidad , Receptores de Antígenos de Linfocitos T alfa-beta/metabolismo , Proteínas de Dominio T Box/metabolismo , Subgrupos de Linfocitos T/metabolismo , Adulto JovenRESUMEN
Clinical and genetic heterogeneity renders confirmation or exclusion of autoimmune lymphoproliferative syndrome difficult. To re-evaluate and improve the currently suggested diagnostic approach to patients with suspected FAS mutation, the most frequent cause of autoimmune lymphoproliferative syndrome, we prospectively determined 11 biomarkers in 163 patients with splenomegaly or lymphadenopathy and presumed or proven autoimmune cytopenia(s). Among 98 patients sequenced for FAS mutations in CD3(+)TCRα/ß(+)CD4(-)CD8(-) "double negative" T cells, 32 had germline and six had somatic FAS mutations. The best a priori predictor of FAS mutations was the combination of vitamin B12 and soluble FAS ligand (cut-offs 1255 pg/mL and 559 pg/mL, respectively), which had a positive predictive value of 92% and a negative predictive value of 97%. We used these data to develop a web-based probability calculator for FAS mutations using the three most discriminatory biomarkers (vitamin B12, soluble FAS ligand, interleukin-10) of the 11 tested. Since more than 60% of patients with lymphoproliferation and autoimmune cytopenia(s) in our cohort did not harbor FAS mutations, 15% had somatic FAS mutations, and the predictive value of double-negative T-cell values was rather low (positive and negative predictive values of 61% and 77%, respectively), we argue that the previously suggested diagnostic algorithm based on determination of double-negative T cells and germline FAS sequencing, followed by biomarker analysis, is not efficient. We propose vitamin B12 and soluble FAS ligand assessment as the initial diagnostic step with subsequent decision on FAS sequencing supported by a probability-calculating tool.
Asunto(s)
Proteína Ligando Fas/sangre , Proteína Ligando Fas/genética , Trastornos Linfoproliferativos/sangre , Trastornos Linfoproliferativos/genética , Vitamina B 12/sangre , Adolescente , Enfermedades Autoinmunes/sangre , Enfermedades Autoinmunes/diagnóstico , Enfermedades Autoinmunes/genética , Biomarcadores/sangre , Estudios de Cohortes , Femenino , Humanos , Trastornos Linfoproliferativos/diagnóstico , MasculinoRESUMEN
BACKGROUND: Profound combined immunodeficiency can present with normal numbers of T and B cells, and therefore the functional defect of the cellular and humoral immune response is often not recognized until the first severe clinical manifestation. Here we report a patient of consanguineous descent presenting at 13 months of age with hypogammaglobulinemia, Pneumocystis jirovecii pneumonia, and a suggestive family history. OBJECTIVE: We sought to identify the genetic alteration in a patient with combined immunodeficiency and characterize human caspase recruitment domain family, member 11 (CARD11), deficiency. METHODS: Molecular, immunologic, and functional assays were performed. RESULTS: The immunologic characterization revealed only subtle changes in the T-cell and natural killer cell compartment, whereas B-cell differentiation, although normal in number, was distinctively blocked at the transitional stage. Genetic evaluation revealed a homozygous deletion of exon 21 in CARD11 as the underlying defect. This deletion abrogated protein expression and activation of the canonical nuclear factor κB (NF-κB) pathway in lymphocytes after antigen receptor or phorbol 12-myristate 13-acetate stimulation, whereas CD40 signaling in B cells was preserved. The abrogated activation of the canonical NF-κB pathway was associated with severely impaired upregulation of inducible T-cell costimulator, OX40, cytokine production, proliferation of T cells, and B cell-activating factor receptor expression on B cells. CONCLUSION: Thus in patients with CARD11 deficiency, the combination of impaired activation and especially upregulation of inducible T-cell costimulator on T cells, together with severely disturbed peripheral B-cell differentiation, apparently leads to a defective T-cell/B-cell cooperation and probably germinal center formation and clinically results in severe immunodeficiency. This report discloses the crucial and nonredundant role of canonical NF-κB activation and specifically CARD11 in the antigen-specific immune response in human subjects.