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1.
Mov Disord ; 2024 Sep 20.
Artículo en Inglés | MEDLINE | ID: mdl-39301998

RESUMEN

BACKGROUND: Seed amplification assay (SAA) testing has been developed as a biomarker for the diagnosis of α-synuclein-related neurodegenerative disorders. OBJECTIVE: The objective of this study was to assess the rate of α-synuclein SAA positivity in progressive supranuclear palsy (PSP) and corticobasal syndrome (CBS) and to analyze clinical and pathological features of SAA-positive and -negative cases. METHODS: A total of 96 cerebrospinal fluid samples from clinically diagnosed PSP (n = 59) and CBS (n = 37) cases were analyzed using α-synuclein SAA. RESULTS: Six of 59 (10.2%) PSP cases were α-synuclein SAA positive, including one case who was MSA-type positive. An exploratory analysis showed that PSP cases who were Parkinson's disease-type positive were older and had a shorter disease duration compared with SAA-negative cases. In contrast, 11 of 37 (29.7%) CBS cases were α-synuclein SAA positive, including two cases who were MSA-type positive. CONCLUSIONS: Our results suggest that α-synuclein seeds can be detected in PSP and CBS using a cerebrospinal fluid α-synuclein SAA, and in PSP this may impact on clinical course. © 2024 The Author(s). Movement Disorders published by Wiley Periodicals LLC on behalf of International Parkinson and Movement Disorder Society.

2.
Alzheimers Dement ; 2024 Oct 20.
Artículo en Inglés | MEDLINE | ID: mdl-39428831

RESUMEN

INTRODUCTION: Cerebrospinal fluid (CSF) α-synuclein (α-syn) seed amplification assay (SAA) is a sensitive and specific tool for detecting Lewy body co-pathology in Alzheimer's disease. METHODS: A total of 1637 cross-sectional and 407 longitudinal CSF samples from the Alzheimer's Disease Neuroimaging Initiative (ADNI) were tested with SAA. We examined longitudinal dynamics of amyloid beta (Aß), α-syn seeds, and phosphorylated tau181 (p-tau181), along with global and domain-specific cognition in stable SAA+, stable SAA-, and those who converted to SAA+ from SAA-. RESULTS: SAA+ individuals had faster cognitive decline than SAA-, notably in mild cognitive impairment, and presented with earlier symptom onset. SAA+ conversion was associated with CSF Aß42 positivity but did not impact the progression of either CSF Aß42 or CSF p-tau181 status. CSF Aß42, p-tau181, and α-syn SAA were all strong predictors of clinical progression, particularly CSF Aß42. In vitro, CSF α-syn SAA kinetic parameters were associated with participant demographics, clinical profiles, and cognitive decline. DISCUSSION: These results highlight the interplay between amyloid and α-syn and their association with disease progression. HIGHLIGHTS: Seed amplification assay (SAA) positivity was associated with greater cognitive decline and earlier symptom onset. Thirty-four Alzheimer's Disease Neuroimaging Initiative (ADNI) individuals progressed from SAA- to SAA+, that is, ≈ 5% conversion. SAA conversion was associated with amyloid beta (Aß) pathology and greater cognitive decline. SAA status did not impact the progression of either CSF Aß42 or phosphorylated tau181 biomarkers. Change in clinical diagnosis was associated with both Alzheimer's disease biomarkers and SAA. SAA kinetic parameters were associated with clinical features and progression.

3.
Alzheimers Dement ; 20(5): 3334-3341, 2024 05.
Artículo en Inglés | MEDLINE | ID: mdl-38539061

RESUMEN

INTRODUCTION: Lewy body disease (LBD) is a common primary or co-pathology in neurodegenerative syndromes. An alpha-synuclein seed amplification assay (αSyn-SAA) is clinically available, but clinical performance, especially lower sensitivity in amygdala-predominant cases, is not well understood. METHODS: Antemortem CSF from neuropathology-confirmed LBD cases was tested with αSyn-SAA (N = 56). Diagnostic performance and clinicopathological correlations were examined. RESULTS: Similar to prior reports, sensitivity was 100% for diffuse and transitional LBD (9/9), and overall specificity was 96.3% (26/27). Sensitivity was lower in amygdala-predominant (6/14, 42.8%) and brainstem-predominant LBD (1/6, 16.7%), but early spread outside these regions (without meeting criteria for higher stage) was more common in αSyn-SAA-positive cases (6/7, 85.7%) than negative (2/13, 15.4%). DISCUSSION: In this behavioral neurology cohort, αSyn-SAA had excellent diagnostic performance for cortical LBD. In amygdala- and brainstem-predominant cases, sensitivity was lower, but positivity was associated with anatomical spread, suggesting αSyn-SAA detects early LBD progression in these cohorts. HIGHLIGHTS: A cerebrospinal fluid alpha-synuclein assay detects cortical LBD with high sensitivity/specificity. Positivity in prodromal stages of LBD was associated with early cortical spread. The assay provides precision diagnosis of LBD that could support clinical trials. The assay can also identify LBD co-pathology, which may impact treatment responses.


Asunto(s)
Autopsia , Enfermedad por Cuerpos de Lewy , Sensibilidad y Especificidad , alfa-Sinucleína , Humanos , alfa-Sinucleína/líquido cefalorraquídeo , Enfermedad por Cuerpos de Lewy/líquido cefalorraquídeo , Enfermedad por Cuerpos de Lewy/patología , Femenino , Masculino , Anciano , Estudios de Cohortes , Amígdala del Cerebelo/patología , Anciano de 80 o más Años , Biomarcadores/líquido cefalorraquídeo , Persona de Mediana Edad
4.
Alzheimers Dement ; 20(8): 5114-5131, 2024 08.
Artículo en Inglés | MEDLINE | ID: mdl-38770829

RESUMEN

INTRODUCTION: Alzheimer's disease (AD) pathology is defined by ß-amyloid (Aß) plaques and neurofibrillary tau, but Lewy bodies (LBs; 𝛼-synuclein aggregates) are a common co-pathology for which effective biomarkers are needed. METHODS: A validated α-synuclein Seed Amplification Assay (SAA) was used on recent cerebrospinal fluid (CSF) samples from 1638 Alzheimer's Disease Neuroimaging Initiative (ADNI) participants, 78 with LB-pathology confirmation at autopsy. We compared SAA outcomes with neuropathology, Aß and tau biomarkers, risk-factors, genetics, and cognitive trajectories. RESULTS: SAA showed 79% sensitivity and 97% specificity for LB pathology, with superior performance in identifying neocortical (100%) compared to limbic (57%) and amygdala-predominant (60%) LB-pathology. SAA+ rate was 22%, increasing with disease stage and age. Higher Aß burden but lower CSF p-tau181 associated with higher SAA+ rates, especially in dementia. SAA+ affected cognitive impairment in MCI and Early-AD who were already AD biomarker positive. DISCUSSION: SAA is a sensitive, specific marker for LB-pathology. Its increase in prevalence with age and AD stages, and its association with AD biomarkers, highlights the clinical importance of α-synuclein co-pathology in understanding AD's nature and progression. HIGHLIGHTS: SAA shows 79% sensitivity, 97% specificity for LB-pathology detection in AD. SAA positivity prevalence increases with disease stage and age. Higher Aß burden, lower CSF p-tau181 linked with higher SAA+ rates in dementia. SAA+ impacts cognitive impairment in early disease stages. Study underpins need for wider LB-pathology screening in AD treatment.


Asunto(s)
Enfermedad de Alzheimer , Péptidos beta-Amiloides , Biomarcadores , Neuroimagen , alfa-Sinucleína , Proteínas tau , Humanos , Enfermedad de Alzheimer/genética , Enfermedad de Alzheimer/patología , Enfermedad de Alzheimer/líquido cefalorraquídeo , alfa-Sinucleína/líquido cefalorraquídeo , Biomarcadores/líquido cefalorraquídeo , Masculino , Femenino , Anciano , Estudios Transversales , Proteínas tau/líquido cefalorraquídeo , Péptidos beta-Amiloides/líquido cefalorraquídeo , Anciano de 80 o más Años , Prevalencia , Cuerpos de Lewy/patología , Cognición/fisiología , Sensibilidad y Especificidad , Encéfalo/patología , Encéfalo/diagnóstico por imagen , Disfunción Cognitiva/genética , Disfunción Cognitiva/líquido cefalorraquídeo
5.
Toxicol Pathol ; 51(1-2): 61-66, 2023 01.
Artículo en Inglés | MEDLINE | ID: mdl-36726336

RESUMEN

Göttingen minipigs are increasingly used as an alternative large animal model in nonclinical toxicology studies, and proliferative lesions in this species are rare. Here, we report four cases of cardiac rhabdomyoma in Göttingen minipigs, an incidental and benign mass in the heart. Three cases lacked gross observations and had a microscopic nodule in either the left ventricle or interventricular septum. The last case had a large, firm, raised nodule on a left ventricular papillary muscle noted at necropsy, with additional microscopic intramural masses in the left ventricular wall. In all cases, microscopic evaluation revealed well-circumscribed, expansile nodules composed of bundles of large, highly vacuolated, ovoid to polygonal cells with variable cytoplasmic processes radiating from a centrally located nucleus. Cells displayed patchy accumulation of intracytoplasmic, PAS-positive material and haphazardly arranged cytoplasmic cross-striations. There was no evidence of cardiac insufficiency or other data to suggest the masses were clinically meaningful. Cardiac rhabdomyomas have been reported in meat-hybrid swine, with a breed predisposition in red wattle. This lesion is well established in guinea pigs, but documentation in other laboratory species used in toxicologic studies is limited to two beagle dogs. To our knowledge, this is the first report of spontaneous cardiac rhabdomyoma in Göttingen minipigs.


Asunto(s)
Rabdomioma , Porcinos , Animales , Perros , Cobayas , Porcinos Enanos , Rabdomioma/veterinaria , Rabdomioma/patología , Corazón , Modelos Animales , Ventrículos Cardíacos/patología
7.
medRxiv ; 2024 Jul 16.
Artículo en Inglés | MEDLINE | ID: mdl-39072013

RESUMEN

INTRODUCTION: CSF α-synuclein seed amplification assay (SAA) is a sensitive and specific tool for detecting Lewy body (LB) co-pathology in AD. METHODS: 1637 cross-sectional and 407 longitudinal CSF samples from ADNI were tested with SAA. We examined longitudinal dynamics of Aß, α-synuclein seeds, and p-tau181, along with global and domain-specific cognition in stable SAA+, stable SAA-, and those who converted to SAA+ from SAA-. RESULTS: SAA+ individuals had faster cognitive decline than SAA-, notably in MCI, and presented with earlier symptom onset. SAA+ conversion was associated with CSF Aß42-positivity but did not impact progression of either Aß42 or p-tau181 status. Aß42, p-tau181, and α-syn SAA were all strong predictors of clinical progression, particularly Aß42. In vitro α-syn SAA kinetic parameters were associated with participant demographics, clinical profiles, and cognitive decline. DISCUSSION: These results highlight the interplay between Aß and α-synuclein and their association with disease progression.

8.
Ann Clin Transl Neurol ; 11(5): 1197-1210, 2024 May.
Artículo en Inglés | MEDLINE | ID: mdl-38436140

RESUMEN

OBJECTIVE: More than half of neurodegenerative disease patients have multiple pathologies at autopsy; however, most receive one diagnosis during life. We used the α-synuclein seed amplification assay (αSyn-SAA) and CSF biomarkers for amyloidosis and Alzheimer's disease (AD) neuropathological change (ADNC) to determine the frequency of co-pathologies in participants clinically diagnosed with Lewy body (LB) disease or AD. METHODS: Using receiver operating characteristic analyses on retrospective CSF samples from 150 participants determined αSyn-SAA accuracy, sensitivity, and specificity for identifying clinically defined LB disease and predicting future change in clinical diagnosis. CSF biomarkers helped determine the frequency of concomitant Lewy body pathology, ADNC, and/or amyloidosis in participants with LB disease and AD, across clinical spectra. RESULTS: Following a decade-long follow-up, the clinically or autopsy-defined diagnosis changed for nine participants. αSyn-SAA demonstrated improved accuracy (91.3%), sensitivity (89.3%), and specificity (93.3%) for identifying LB disease compared to all non-LB disease, highlighting the limitations of clinical diagnosis alone. When examining biomarkers of co-pathology, amyloidosis was present in 18%, 48%, and 71% (χ2(2) = 13.56, p = 0.001) and AD biomarkers were present in 0%, 8.7%, and 42.9% (χ2(2) = 18.44, p < 0.001) of LB disease participants with different stages of cognitive impairment respectively. Co-occurring biomarkers for αSyn-SAA and amyloidosis were present in 12% and 14% of AD compared to 43% and 57% LB disease participants with different stages of cognitive impairment (χ2(3) = 13.87, p = 0.003). INTERPRETATION: Our study shows that using a combination of αSyn-SAA and AD biomarkers can identify people with αSyn, ADNC, and co-pathology better and earlier than traditional clinical diagnostic criteria alone.


Asunto(s)
Enfermedad de Alzheimer , Biomarcadores , Enfermedad por Cuerpos de Lewy , alfa-Sinucleína , Humanos , Enfermedad de Alzheimer/diagnóstico , Enfermedad de Alzheimer/líquido cefalorraquídeo , Enfermedad por Cuerpos de Lewy/diagnóstico , Enfermedad por Cuerpos de Lewy/líquido cefalorraquídeo , Anciano , Biomarcadores/líquido cefalorraquídeo , Masculino , Femenino , alfa-Sinucleína/líquido cefalorraquídeo , Anciano de 80 o más Años , Estudios Retrospectivos , Persona de Mediana Edad , Amiloidosis/diagnóstico , Amiloidosis/líquido cefalorraquídeo , Sensibilidad y Especificidad
9.
medRxiv ; 2024 Oct 13.
Artículo en Inglés | MEDLINE | ID: mdl-39417113

RESUMEN

INTRODUCTION: Multi-etiology dementia necessitates in-vivo markers of copathologies including misfolded α -synuclein (syn). We measured misfolded syn aggregates (syn-seeds) via qualitative seed amplifcation assays (synSAA) and examined relationships with markers of Alzheimer's disease (AD). METHODS: Cerebrospinal fluid (CSF) was obtained from 420 participants in two Wisconsin AD risk cohorts (35% male; 91% cognitively unimpaired; mean (SD) age, 65.42 (7.78) years; education, 16.17 (2.23) years). synSAA results were compared to phosphorylated tau (T), beta amyloid (A), and clinical outcomes. Longitudinal cognition was modeled with mixed effects. RESULTS: Syn positivity (synSAA+) co-occurred with T (in synSAA+ vs synSAA-, 36% vs 20% T+; p=0.011) and with cognitive impairment (10% vs 7% MCI; 10% vs 0% dementia; p=0.00050). synSAA+ participants' cognitive performance declined ∼40% faster than synSAA-for Digit Symbol, but not other tests. DISCUSSION: Findings support prevalent syn copathology in a mostly-unimpaired AD risk cohort. Future work will explore relationships with disease progression.

10.
Am J Surg Pathol ; 44(9): 1224-1234, 2020 09.
Artículo en Inglés | MEDLINE | ID: mdl-32804454

RESUMEN

This study determined the frequency and the clinicopathologic and genetic features of colorectal carcinomas driven by oncogenic fusions of the anaplastic lymphoma kinase gene (ALK). Of the 8150 screened tumors, 12 (0.15%) were immunohistochemically ALK-positive with D5F3 antibody. These cancers harbored CAD-ALK (n=1), DIAPH2-ALK (n=2), EML4-ALK (n=2), LOC101929227-ALK (n=1), SLMAP-ALK (n=1), SPTBN1-ALK (n=4), and STRN-ALK (n=1) fusions, as detected by an RNA-based next-generation sequencing assay. ALK fusion carcinomas were diagnosed mostly in older patients with a 9:3 female predominance (median age: 72 y). All tumors, except a rectal one, occurred in the right colon. Most tumors were stage T3 (n=7) or T4 (n=3). Local lymph node and distant metastases were seen at presentation in 9 and 2 patients. These tumors showed moderate (n=6) or poor (n=3) glandular differentiation, solid medullary growth pattern (n=2), and pure mucinous morphology (n=1). DNA mismatch repair-deficient phenotype was identified in 10 cases. Tumor-infiltrating lymphocytes were prominent in 9 carcinomas. In 4 carcinomas, tumor cells showed strong, focal (n=3), or diffuse programmed death-ligand 1 immunoreactivity. CDX2 expression and loss of CK20 and MUC2 expression were frequent. CK7 was expressed in 5 tumors. Four patients died of disease within 3 years, and 7 were alive with follow-up ranging from 1 to 8 years. No mutations in BRAF, RAS, and in genes encoding components of PI3K-AKT/MTOR pathway were identified. However, 1 tumor had a loss-of-function PTEN mutation. Aberration of p53 signaling, TP53 mutations, and/or nuclear accumulation of p53 protein was seen in 9 cases. ALK fusion colorectal carcinomas are a distinct and rare subtype of colorectal cancers displaying some features of mismatch repair-deficient tumors.


Asunto(s)
Adenocarcinoma/genética , Quinasa de Linfoma Anaplásico/genética , Biomarcadores de Tumor/genética , Neoplasias Colorrectales/genética , Fusión Génica , Reordenamiento Génico , Adenocarcinoma/química , Adenocarcinoma/secundario , Adenocarcinoma/terapia , Anciano , Biomarcadores de Tumor/análisis , Neoplasias Colorrectales/química , Neoplasias Colorrectales/patología , Neoplasias Colorrectales/terapia , Análisis Mutacional de ADN , Europa (Continente) , Femenino , Predisposición Genética a la Enfermedad , Humanos , Inmunohistoquímica , Hibridación Fluorescente in Situ , Japón , Metástasis Linfática , Masculino , Mutación , Estadificación de Neoplasias , Fenotipo , Resultado del Tratamiento , Estados Unidos
11.
Am J Surg Pathol ; 44(2): 162-173, 2020 02.
Artículo en Inglés | MEDLINE | ID: mdl-31567189

RESUMEN

This study was undertaken to determine the frequency, and the clinicopathologic and genetic features, of colon cancers driven by neurotrophic receptor tyrosine kinase (NTRK) gene fusions. Of the 7008 tumors screened for NTRK expression using a pan-Trk antibody, 16 (0.23%) had Trk immunoreactivity. ArcherDx assay detected TPM3-NTRK1 (n=9), LMNA-NTRK1 (n=3), TPR-NTRK1 (n=2) and EML4-NTRK3 (n=1) fusion transcripts in 15 cases with sufficient RNA quality. Patients were predominantly women (median age: 63 y). The tumors involved the right (n=12) and left colon unequally and were either stage T3 (n=12) or T4. Local lymph node and distant metastases were seen at presentation in 6 and 1 patients, respectively. Lymphovascular invasion was present in all cases. Histologically, tumors showed moderate to poor (n=11) differentiation with a partly or entirely solid pattern (n=5) and mucinous component (n=10), including 1 case with sheets of signet ring cells. DNA mismatch repair-deficient phenotype was seen in 13 cases. Tumor-infiltrating CD4/CD8 lymphocytes were prominent in 9 cases. Programmed death-ligand 1 positive tumor-infiltrating immune cells and focal tumor cell positivity were seen in the majority of cases. CDX2 expression and loss of CK20 and MUC2 expression were frequent. CK7 was expressed in 5 cases. No mutations in BRAF, RAS, and PIK3CA were identified. However, other genes of the PI3K-AKT/MTOR pathway were mutated. In several cases, components of Wnt/ß-catenin (APC, AMER1, CTNNB1), p53, and TGFß (ACVR2A, TGFBR2) pathways were mutated. However, no SMAD4 mutations were found. Two tumors harbored FBXW7 tumor suppressor gene mutations. NTRK fusion tumors constitute a distinct but rare subgroup of colorectal carcinomas.


Asunto(s)
Adenocarcinoma/diagnóstico , Adenocarcinoma/genética , Biomarcadores de Tumor/genética , Neoplasias del Colon/diagnóstico , Neoplasias del Colon/genética , Proteínas de Fusión Oncogénica/genética , Proteínas Tirosina Quinasas Receptoras/genética , Adenocarcinoma/patología , Anciano , Anciano de 80 o más Años , Biomarcadores de Tumor/metabolismo , Neoplasias del Colon/patología , Femenino , Estudios de Seguimiento , Regulación Neoplásica de la Expresión Génica , Humanos , Inmunohistoquímica , Masculino , Glicoproteínas de Membrana/genética , Glicoproteínas de Membrana/metabolismo , Persona de Mediana Edad , Estadificación de Neoplasias , Fusión de Oncogenes , Proteínas de Fusión Oncogénica/metabolismo , Proteínas Tirosina Quinasas Receptoras/metabolismo , Receptor trkA/genética , Receptor trkA/metabolismo , Receptor trkB/genética , Receptor trkB/metabolismo , Receptor trkC/genética , Receptor trkC/metabolismo
12.
Appl Immunohistochem Mol Morphol ; 25(7): 513-523, 2017 08.
Artículo en Inglés | MEDLINE | ID: mdl-27028240

RESUMEN

Targeted therapy combined with companion diagnostics has led to the advancement of next-generation sequencing (NGS) for detection of molecular alterations. However, using a diagnostic test to identify patient populations with low prevalence molecular alterations, such as gene rearrangements, poses efficiency, and cost challenges. To address this, we have developed a 2-step diagnostic test to identify NTRK1, NTRK2, NTRK3, ROS1, and ALK rearrangements in formalin-fixed paraffin-embedded clinical specimens. This test is comprised of immunohistochemistry screening using a pan-receptor tyrosine kinase cocktail of antibodies to identify samples expressing TrkA (encoded by NTRK1), TrkB (encoded by NTRK2), TrkC (encoded by NTRK3), ROS1, and ALK followed by an RNA-based anchored multiplex polymerase chain reaction NGS assay. We demonstrate that the NGS assay is accurate and reproducible in identification of gene rearrangements. Furthermore, implementation of an RNA quality control metric to assess the presence of amplifiable nucleic acid input material enables a measure of confidence when an NGS result is negative for gene rearrangements. Finally, we demonstrate that performing a pan-receptor tyrosine kinase immunohistochemistry staining enriches detection of the patient population for gene rearrangements from 4% to 9% and has a 100% negative predictive value. Together, this 2-step assay is an efficient method for detection of gene rearrangements in both clinical testing and studies of archival formalin-fixed paraffin-embedded specimens.


Asunto(s)
Reordenamiento Génico , Secuenciación de Nucleótidos de Alto Rendimiento/métodos , Coloración y Etiquetado/métodos , Femenino , Humanos , Inmunohistoquímica/métodos , Masculino , Adhesión en Parafina
13.
J Vet Diagn Invest ; 23(2): 312-5, 2011 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-21398453

RESUMEN

Diagnostic laboratories are frequently required to assess the antemortem nutritional condition of deceased animals. The percentage of fat in the bone marrow is used to diagnose starvation because this fat depot is typically the last in the body to be depleted. Diagnosticians rely on measurement of bone marrow adipose content using fat solvent-extraction methods; however, the effects of tissue storage conditions before processing have not been fully assessed. The current study focuses on evaluating the effects of 3 storage conditions (refrigeration [4 °C], freezing [-20 °C], and ambient temperature [9.9-34.4 °C]) on the percentage of fat in the bone marrow from 3 species. Equine, bovine, and canine humeri and femurs were removed within 24 hr of death from adult animals in adequate body condition and then stored as described for a minimum of 30-60 days. Bone marrow was harvested from these tissues at the time of necropsy and after 30-60 days. Percentage of fat was measured using an automated solvent extractor. Mean percentage of fat in the bone marrow in initial equine, bovine, and canine samples was 81.75%, 86.33%, and 59.96%, respectively. The results indicate that bovine and equine percentage of fat in bone marrow does not change after 30-60 days, regardless of the storage condition, whereas the fat content from canine tissues varies when stored at ambient temperatures. Results suggest that postmortem interval and environmental conditions of samples must be considered in the postmortem evaluation of bone marrow fat concentration in at least some species.


Asunto(s)
Médula Ósea/química , Lípidos/análisis , Desnutrición/veterinaria , Manejo de Especímenes/veterinaria , Animales , Bovinos , Perros , Caballos , Desnutrición/diagnóstico , Distribución Aleatoria , Manejo de Especímenes/métodos
14.
J Exp Med ; 204(12): 2853-64, 2007 Nov 26.
Artículo en Inglés | MEDLINE | ID: mdl-17967905

RESUMEN

The initial B cell repertoire contains a considerable proportion of autoreactive specificities. The first major B cell tolerance checkpoint is at the stage of the immature B cell, where receptor editing is the primary mode of eliminating self-reactivity. The cells that emigrate from the bone marrow have a second tolerance checkpoint in the transitional compartment in the spleen. Although it is known that the second checkpoint is defective in lupus, it is not clear whether there is any breakdown in central B cell tolerance in the bone marrow. We demonstrate that receptor editing is less efficient in the lupus-prone strain MRL/lpr. In an in vitro system, when receptor-editing signals are given to bone marrow immature B cells by antiidiotype antibody or after in vivo exposure to membrane-bound self-antigen, MRL/lpr 3-83 transgenic immature B cells undergo less endogenous rearrangement and up-regulate recombination activating gene messenger RNA to a lesser extent than B10 transgenic cells. CD19, along with immunoglobulin M, is down-regulated in the bone marrow upon receptor editing, but the extent of down-regulation is fivefold less in MRL/lpr mice. Less efficient receptor editing could allow some autoreactive cells to escape from the bone marrow in lupus-prone mice, thus predisposing to autoimmunity.


Asunto(s)
Lupus Eritematoso Sistémico/genética , Edición de ARN/genética , Receptores de Antígenos de Linfocitos B/genética , Animales , Linfocitos B/inmunología , Células de la Médula Ósea/inmunología , Células de la Médula Ósea/fisiología , Células Cultivadas , Predisposición Genética a la Enfermedad , Interleucina-7/fisiología , Ratones , Ratones Endogámicos MRL lpr , Ratones Endogámicos , Ratones Transgénicos , Reacción en Cadena de la Polimerasa , Receptores de Antígenos de Linfocitos B/fisiología
16.
Arthritis Res Ther ; 8(4): R134, 2006.
Artículo en Inglés | MEDLINE | ID: mdl-16872515

RESUMEN

Relapsing polychondritis (RP) is a human autoimmune disease of unknown etiology in which cartilaginous sites are destroyed by cyclic inflammatory episodes beginning, most commonly, during the fourth or fifth decade of life. We have previously described collagen-induced polychondritis that closely mirrors RP occurring in young (6-8 weeks old) HLA-DQ6alphabeta 8alphabeta transgenic Abeta0 mice, following immunization with heterologous type II collagen (CII). We present evidence here that transgenic strains expressing the DQ6alpha8beta transgene develop spontaneous polychondritis (SP) at the mouse equivalent of human middle age (4.5-6 months and 40-50 years old, respectively) and display polyarthritis, auricular chondritis and nasal chondritis--three of the most common sites affected in RP. Auricular chondritis in SP, like RP but unlike CII-induced polychondritis, exhibited a relapsing/remitting phenotype, requiring several inflammatory cycles before the cartilage is destroyed. Elevated serum levels of total IgG corresponded with the onset of disease in SP, as in RP and CII-induced polychondritis. No CII-specific immune response was detected in SP, however--more closely mirroring RP, in which as few as 30% of RP patients have been reported to have CII-specific IgG. CII-induced polychondritis displays a strong CII-specific immune response. SP also demonstrated a strong female preponderance, as some workers have reported in RP but has not observed in CII-induced polychondritis. These characteristics of SP allow for the examination of the immunopathogenesis of polychondritis in the absence of an overwhelming CII-specific immune response and the strong adjuvant-induced immunostimulatory influence in CII-induced polychondritis. This spontaneous model of polychondritis provides a new and unique tool to investigate both the initiatory events as well as the immunopathogenic mechanisms occurring at cartilaginous sites during the cyclic inflammatory assaults of polychondritis.


Asunto(s)
Modelos Animales de Enfermedad , Antígenos HLA-DQ/genética , Ratones Transgénicos/genética , Policondritis Recurrente/genética , Transgenes , Animales , Cartílago/patología , Cartílago Auricular/patología , Femenino , Inmunoglobulina G/sangre , Masculino , Ratones , Nariz , Fenotipo , Policondritis Recurrente/sangre , Policondritis Recurrente/patología , Factores Sexuales
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