RESUMEN
AIMS: To establish the prevalence of diabetes distress, perceived stress and depressive symptoms among adults with early-onset Type 2 diabetes, and to examine their association with socio-demographic and clinical characteristics. METHODS: A cross-sectional survey was performed among individuals with Type 2 diabetes aged 20-45 years who were included in the Danish nationwide Danish Center for Strategic Research in Type 2 Diabetes cohort between 2010 and 2016. The survey assessed diabetes distress (20-item Problem Areas in Diabetes Scale), perceived stress (10-item Perceived Stress Scale) and depressive symptoms (10-item short form of the Center for Epidemiological Studies Depression Scale Revised), as well as socio-demographic characteristics. Clinical data were collected from national health registers. RESULTS: In total, 216/460 (47%) individuals (48% women) with Type 2 diabetes completed the survey. The median (IQR) age was 42 (38-44) years and the diabetes duration was 5 (3-7) years. In total, 24% of respondents reported high diabetes distress (Problem Areas in Diabetes Scale ≥ 40), 46% reported high perceived stress (Perceived Stress Scale ≥ 18) and 41% reported elevated symptoms of depression (Center for Epidemiological Studies Depression Scale Revised ≥ 10). The prevalence of emotional problems was higher among women than men. Diabetes distress was higher among those prescribed non-insulin glucose-lowering drugs (vs. no glucose-lowering drugs), but was not associated with other clinical or socio-demographic characteristics. High perceived stress was associated with being unemployed and using antidepressant medication, and elevated depressive symptoms were associated with low education level, unemployment, living alone, having a psychiatric disorder and using antidepressant medication. CONCLUSION: We found a high prevalence of emotional problems among adults with early-onset Type 2 diabetes in Denmark. Health care for this group should focus on both physical health and psychosocial circumstances and should also address general as well as diabetes-specific emotional problems.
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Depresión/epidemiología , Diabetes Mellitus Tipo 2/psicología , Estrés Psicológico/epidemiología , Adulto , Edad de Inicio , Antidepresivos/uso terapéutico , Estudios Transversales , Dinamarca/epidemiología , Depresión/psicología , Femenino , Humanos , Masculino , Trastornos Mentales/tratamiento farmacológico , Persona de Mediana Edad , Prevalencia , Distrés Psicológico , Factores de Riesgo , Estrés Psicológico/psicología , Adulto JovenRESUMEN
OBJECTIVE: To investigate temporal changes in structural progression assessed by serial conventional radiography and magnetic resonance imaging (MRI) of the sacroiliac joints (SIJs) and spine in patients with ankylosing spondylitis (AS) treated with tumour necrosis factor (TNF) inhibitor for 5 years. METHOD: Forty-two patients were included and 33 patients were followed for 5 years in a prospective investigator-initiated study. Conventional radiographs were required four times and MRI seven times. The modified Stoke Ankylosing Spondylitis Spinal Score (mSASSS); Spondyloarthritis Research Consortium of Canada (SPARCC) MRI SIJ and Spine Inflammation, and SPARCC MRI SIJ Structural Score (SSS) for Fat, Erosion, Backfill, and Ankylosis; and the Canada-Denmark MRI scores for Spine Inflammation, Fat, Erosion, and New Bone Formation (NBF) were applied. RESULTS: Compared with baseline, MRI Inflammation had decreased significantly at week 22 (spine)/week 46 (SIJ) and thereafter. MRI SIJ Fat (from week 22), SIJ Ankylosis, Spine NBF, and mSASSS had increased significantly at week 46 and thereafter. SIJ Erosion had decreased from year 2. The annual progression rate in mSASSS was significantly higher during weeks 0-46 compared to week 46 to year 3. In multivariate regression analyses, baseline SIJ Inflammation and Backfill were independent predictors of 5 year progression in SIJ Ankylosis. Spine Erosion predicted progression in Spine NBF. Longitudinally, Ankylosing Spondylitis Disease Activity Score, Bath Ankylosing Spondylitis Disease Activity Index, MRI Spine Inflammation, Fat, and Erosion scores were significantly associated with mSASSS. SIJ Inflammation, Fat, Erosion, and Backfill scores were longitudinally associated with SIJ Ankylosis. Structural progression was not associated with body mass index, smoking, or Assessment of SpondyloArthritis international Society Non-Steroidal Anti-Inflammatory Drug Index. CONCLUSION: In a 5 year follow-up study of patients with AS treated with TNF inhibitor, structural progression decreased over time.
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Antirreumáticos/uso terapéutico , Imagen por Resonancia Magnética , Radiografía , Articulación Sacroiliaca , Espondilitis Anquilosante , Factor de Necrosis Tumoral alfa/antagonistas & inhibidores , Adulto , Progresión de la Enfermedad , Femenino , Estudios de Seguimiento , Humanos , Imagen por Resonancia Magnética/métodos , Imagen por Resonancia Magnética/estadística & datos numéricos , Masculino , Persona de Mediana Edad , Evaluación de Resultado en la Atención de Salud , Estudios Prospectivos , Radiografía/métodos , Radiografía/estadística & datos numéricos , Articulación Sacroiliaca/diagnóstico por imagen , Articulación Sacroiliaca/patología , Índice de Severidad de la Enfermedad , Espondilitis Anquilosante/diagnóstico , Espondilitis Anquilosante/tratamiento farmacológico , Espondilitis Anquilosante/fisiopatologíaRESUMEN
OBJECTIVES: To investigate the impact of enhanced infusion rate of tocilizumab on the occurrence of infusion reactions, overall safety, and efficacy in rheumatoid arthritis (RA). METHOD: We conducted a 24-week multicentre, open-label, randomized parallel group study comparing adverse event (AE) and effect profiles following tocilizumab IV 8 mg/kg every 4 weeks over 31 min vs. standard 60-min infusions in patients with RA and an inadequate clinical response to disease-modifying anti-rheumatic drugs (DMARDs) and/or tumour necrosis factor (TNF)-α inhibitors. RESULTS: A total of 47 patients were enrolled in the study and randomized to fast infusions (n = 25) and controls (n = 22). Incidences of infusion reactions were similar between the two groups, neither of them leading to withdrawal. Likewise, the incidence of additional AEs did not differ between the treatment arms. Two serious adverse events (SAEs) were reported, in the control group. Four patients withdrew due to AEs, two from each arm. Efficacy at week 24 was comparable between groups. CONCLUSIONS: In RA, monthly tocilizumab infusions of 8 mg/kg provided over 31 or 60 min during 24 weeks did not differ concerning safety or efficacy.
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Anticuerpos Monoclonales Humanizados/administración & dosificación , Antirreumáticos/administración & dosificación , Artritis Reumatoide/tratamiento farmacológico , Anciano , Anticuerpos Monoclonales Humanizados/efectos adversos , Antirreumáticos/efectos adversos , Artritis Reumatoide/inmunología , Proteína C-Reactiva/inmunología , Hipersensibilidad a las Drogas/etiología , Edema/inducido químicamente , Fatiga/inducido químicamente , Femenino , Rubor/inducido químicamente , Glucocorticoides/uso terapéutico , Cefalea/inducido químicamente , Humanos , Hipercolesterolemia/inducido químicamente , Infusiones Intravenosas , Masculino , Metotrexato/uso terapéutico , Persona de Mediana Edad , Nasofaringitis/inducido químicamente , Neutropenia/inducido químicamente , Resultado del Tratamiento , Factor de Necrosis Tumoral alfa/antagonistas & inhibidoresRESUMEN
OBJECTIVES: We aimed to determine 1) ultrasound (US) abnormalities in patients with systemic lupus erythematosus (SLE) with and without hand arthralgia at the day of examination compared with clinical evaluation and healthy controls, and 2) inter-observer reliability of the US abnormalities. METHODS: Thirty-three female SLE patients were twice examined with US by three trained examiners. Using B-mode and Doppler US, unilateral wrist and metacarpophalangeal (MCP) joints were examined for synovitis and erosions as well as signs of hand tenosynovitis using a GE Logiq 9 US machine with Doppler settings for slow flow. All patients also underwent clinical joint evaluation and were compared with 11 healthy controls (HC). RESULTS: Among the patients with SLE 16 (48%) had signs of wrist synovitis, which was only observed in one HC (p = 0.03). Corresponding figures for any MCP joint were 12 (36%) and 0 (p = 0.06). In SLE patients, 18% had hand tenosynovitis and 6% bone erosions. Wrist synovitis was detected by US in 16 SLE patients (81%) with arthralgia compared with 17 patients without (18%) (p = 0.0005). Any US abnormalities were observed in 44% of 25 wrists without tenderness at clinical examination and in 46% of 26 wrists without swelling. Corresponding percentages for MCP2 joints were 27% and 21%. Inter-observer reliability of the US findings was good to excellent for examination of hand joints and tendons. CONCLUSIONS: A majority of SLE patients with hand arthralgia showed US signs of synovitis, erosions and tenosynovitis indicating subclinical disease. Even SLE patients without clinical signs of joint inflammation demonstrated US abnormalities. Good to excellent inter-observer reliability was found in US evaluation of hands in patients with SLE.
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Lupus Eritematoso Sistémico/diagnóstico por imagen , Lupus Eritematoso Sistémico/patología , Articulación Metacarpofalángica/diagnóstico por imagen , Articulación Metacarpofalángica/patología , Articulación de la Muñeca/diagnóstico por imagen , Articulación de la Muñeca/patología , Adolescente , Adulto , Anciano , Artralgia/diagnóstico por imagen , Artralgia/patología , Dinamarca , Femenino , Humanos , Persona de Mediana Edad , Dolor Musculoesquelético/patología , Variaciones Dependientes del Observador , Reproducibilidad de los Resultados , Tenosinovitis/diagnóstico por imagen , Tenosinovitis/patología , Ultrasonografía Doppler/métodos , Adulto JovenRESUMEN
A simplified enzyme-linked immunospot (ELISPOT) technique is described for the detection of cells secreting antibodies to tetanus toxoid (TT), diphtheria toxoid (DT) or Haemophilus influenzae type b capsular polysaccharide (PRP). By combining the cell suspension with the enzyme-linked secondary antibodies in one incubation, the second incubation and washing procedure could be omitted from the original technique. The simplified assay had the same sensitivity for anti-TT and anti-DT spot-forming cells as the ordinary ELISPOT assay. The IgG anti-PRP spots were, however, improved both in quality and in quantity (median: 40% more spots), while the detection of IgM and IgA anti-PRP spot-forming cells was the same in the two techniques. This simplified technique can probably also be used to save time in other antigen systems and should be considered when designing ELISPOT assays for the detection of polysaccharide-specific antibody-secreting cells.
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Antígenos Bacterianos/inmunología , Cápsulas Bacterianas/inmunología , Haemophilus influenzae/inmunología , Técnicas para Inmunoenzimas , Polisacáridos Bacterianos/inmunología , Anticuerpos Antibacterianos/análisis , Toxoide Diftérico/inmunología , Humanos , Isotipos de Inmunoglobulinas/análisis , Toxoide Tetánico/inmunologíaRESUMEN
A case of the rare genetic trisomy 22 in a live calf is described. The calf had low blood thyroxine level and low growth rate. It had several defects including brachygnathia superior, strabismus convergence, aortal cusp insufficiency and hypertrophy of clitoris. Chromosome analysis was performed on cultured blood lymphocytes and fibroblast cells. In all counted metaphases 61 chromosomes were present. The extra chromosome was identified as a chromosome 22 by R-banding. The defects of the calf have similarities with cases of partial trisomy 3p25-pter in human. This section of the human chromosome 3 corresponds to sections of cattle chromosome 22.
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Bovinos/anomalías , Aberraciones Cromosómicas/genética , Trisomía/genética , Animales , Aorta/anomalías , Bovinos/genética , Bandeo Cromosómico/veterinaria , Clítoris/anomalías , Esotropía/genética , Esotropía/veterinaria , Femenino , Tiroxina/sangreRESUMEN
We describe a hitherto unknown functional IGKV gene, VkLa, belonging to the IGKV1 subgroup with exon 2 having only 94% similarity to the closest known IGKV gene, 1-13/1D-13 (L4/L18a). Genomic DNA sequences spanning from 5' of the decanucleotide box to 3' of the heptamer (649 bp) were cloned and sequenced from four individuals. The new gene encodes the conserved amino acids in the exons and contains no apparent defects in known regulatory intron sequences such as pd-box, dc-box, TATA-box, CCCT-elements, splice-sequences, initiation codon, and heptamer sequence. VkLa is therefore potentially functional and, correspondingly, we found transcripts of properly rearranged VkLa with somatical hypermutations. VkLa was found in 12 of 57 (21%) healthy Caucasians by a nested polymerase chain reaction and subsequent sequencing of exon 2. This finding shows that there is more inter-individual variation in the available IGKV gene repertoire than was hitherto assumed. Finally, we describe a minor correction in the IGKV1D-43 (L23) gene sequence.
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Inmunoglobulinas/genética , Secuencia de Aminoácidos , Secuencia de Bases , Cromosomas Humanos Par 2 , Clonación Molecular , ADN , Expresión Génica , Frecuencia de los Genes , Genes de Inmunoglobulinas , Humanos , Cadenas Ligeras de Inmunoglobulina/genética , Datos de Secuencia Molecular , Familia de MultigenesRESUMEN
Protective antibodies to the important childhood pathogen Haemophilus influenzae type b (Hib) are directed against the capsular polysaccharide (HibCP). Most of the antibody is encoded by a well-defined set of ("canonical") immunoglobulin genes, including the Vkappa A2 gene, and expresses an idiotypic marker (HibId-1). In comparison to noncanonical antibodies, the canonical antibody is generally of higher avidity, shows higher levels of in vitro bactericidal activity, and is more protective in infant rats. Using site-directed mutagenesis, we here characterize canonical HibCP antibodies expressed as antigen-binding fragments (Fabs) in Escherichia coli, define amino acids involved in antigen binding and idiotype expression, and propose a three-dimensional structure for the variable domains. We found that canonical Fabs, unlike a noncanonical Fab, bound effectively to HibCP in the absence of somatic mutations. Nevertheless, pronounced mutation-based affinity maturation was demonstrated in vivo. An almost perfect correlation was found between unmutated gene segments that mediated binding in vitro and those encoding canonical HibCP antibodies in vivo. Thus, the Vkappa A2a gene could be replaced by the A2c gene but not by the highly homologous sister gene, A18b, corresponding to the demonstrated usage of A2c but not of A18b in vivo. Similarly, only Jkappa1 and Jkappa3, which predominate in the response in vivo, were able to facilitate binding in vitro. These findings suggest that the restricted immunoglobulin gene usage in HibCP antibodies reflects strict structural demands ensuring relatively high affinity prior to somatic mutations-requirements met by only a limited spectrum of immunoglobulin gene combinations.
Asunto(s)
Anticuerpos Antibacterianos/química , Haemophilus influenzae tipo b/inmunología , Secuencia de Aminoácidos , Animales , Anticuerpos Antibacterianos/genética , Afinidad de Anticuerpos , Secuencia de Bases , Niño , Clonación Molecular , Cartilla de ADN/genética , Escherichia coli/genética , Genes de Inmunoglobulinas , Infecciones por Haemophilus/genética , Infecciones por Haemophilus/inmunología , Infecciones por Haemophilus/prevención & control , Humanos , Fragmentos Fab de Inmunoglobulinas/química , Fragmentos Fab de Inmunoglobulinas/genética , Fragmentos de Inmunoglobulinas/química , Fragmentos de Inmunoglobulinas/genética , Modelos Moleculares , Datos de Secuencia Molecular , Mutagénesis Sitio-Dirigida , Polisacáridos Bacterianos/inmunología , Conformación Proteica , Ratas , Proteínas Recombinantes/química , Proteínas Recombinantes/genética , Proteínas Recombinantes/inmunologíaRESUMEN
Recently, conjugate vaccines containing Haemophilus influenzae type b capsular polysaccharide (HibCP) coupled to protein carriers were introduced for use in infants and certain adult risk groups. Similar conjugate vaccines against other capsulated bacteria are currently under development for both children and adults. Despite its potential importance, the possible influence of preexisting immunity to the components of such conjugates on the vaccination response in humans has been addressed by few studies. To study this issue, we randomized 82 healthy adult volunteers into six groups and vaccinated them twice, with a 4-week interval between immunizations. Four groups received tetanus toxoid (TT) or diphtheria toxoid (DT) and then HibCP coupled to TT (HibCP-TT) or DT (HibCP-DT). Two groups received HibCP-TT followed by HibCP-DT or vice versa. The total antibody levels to HibCP, TT, and DT and the anti-HibCP immunoglobulin G1 (IgG1) and IgG2 levels were measured before and 4 weeks after the immunizations. For some of the vaccinees, the number of circulating antibody-secreting cells was evaluated 7 days after immunization. Surprisingly, preimmunization with the relevant carrier protein reduced the subsequent increase in the total HibCP antibody levels (P < 0.05), affecting the IgG1 and the IgG2 subclasses equally. Also, the responses to the carrier portions of the conjugates were suppressed, as demonstrated by the lack of significant increases in the antibody levels (P > or = 0.29) and, for HibCP-TT, by reduced numbers of anticarrier antibody-secreting cells (P = 0.009). Similar non-epitope-specific suppression was seen in the groups receiving both conjugates. Thus, preimmunization with one conjugate reduced the subsequent response to the carrier portion of the other conjugate (HibCP-DT and then HibCP-TT, P = 0.00002; HibCP-TT and then HibCP-DT, P = 0.06) as well as to HibCP itself. Possible mechanisms behind this non-epitope-specific suppression and its relevance for vaccine development are discussed.
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Anticuerpos Antibacterianos/biosíntesis , Vacunas Bacterianas/inmunología , Toxoide Diftérico/inmunología , Epítopos , Vacunas contra Haemophilus , Toxoide Tetánico/inmunología , Adulto , Complejo Antígeno-Anticuerpo/fisiología , Humanos , Tolerancia Inmunológica , Inmunización , Inmunoglobulina G/biosíntesis , MasculinoRESUMEN
The influence of preexisting immunity on the heavy-chain isotypes of circulating antibody-secreting cells (AbSC) induced by vaccination with Haemophilus influenzae type b (Hib) capsular polysaccharide (HibCP) coupled to tetanus toxoid (TT) or diphtheria toxoid (DT) and by vaccination with TT or DT alone in 51 healthy adults and 9 infants was studied. In adults, the isotypes of TT and DT AbSC were dominated by immunoglobulin G1 (IgG1) followed by IgG4 and IgA1. HibCP AbSC were dominated by the isotype IgA1 followed by (in decreasing order) IgG2, IgA2, IgM, and IgG1. The isotype distributions of TT and DT AbSC were independent of whether the toxoids were coupled to HibCP, and the isotypes of HibCP AbSC were not influenced by the nature of the carrier (TT or DT). Furthermore, the isotype distributions were unaffected by recent immunization with components of the conjugates, although this reduced the numbers of AbSC. The heavy-chain gene usage of HibCP AbSC in adults differed clearly from that in infants, which was restricted largely to the genes mu, gamma 1, and alpha 1, all lying upstream in the heavy-chain constant-region gene locus, while the usage in adults also, to different extents, involved the downstream genes gamma 2 and alpha 2. The ratio between the numbers of HibCP AbSC using heavy-chain genes from the downstream duplication unit (gamma 2, gamma 4, and alpha 2) and those using genes from the upstream duplication unit (gamma 3, gamma 1, and alpha 1) correlated with the preimmunization level of natural HibCP antibodies (r = 0.59; P = 0.00002). A possible role of natural exposure for Hib or cross-reactive bacteria on the mucosal surfaces in the shaping of the isotype response to HibCP conjugate vaccines is discussed.
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Anticuerpos Antibacterianos/biosíntesis , Células Productoras de Anticuerpos/inmunología , Vacunas contra Haemophilus/inmunología , Haemophilus influenzae/inmunología , Cadenas Pesadas de Inmunoglobulina/biosíntesis , Isotipos de Inmunoglobulinas/biosíntesis , Polisacáridos Bacterianos/inmunología , Adulto , Factores de Edad , Cápsulas Bacterianas , Femenino , Humanos , Cadenas Pesadas de Inmunoglobulina/genética , Lactante , Masculino , VacunaciónRESUMEN
The Ab response of a healthy adult to the first dose of a Haemophilus influenzae type b capsular polysaccharide (HibCP) conjugate vaccine was studied at the level of Ig gene usage by circulating Ab-secreting cells. Forty-one IgA and 17 IgG mRNA sequences were obtained. The major part of the response was confined to IgA Ab-secreting cells, and 72% of the IgA sequences were derived from the progeny of a single rearranged B cell. These sequences could be arranged in a genealogical tree showing multiple somatic mutations and at least two intraclonal isotype switches to IgA2. Fourteen somatic mutations were shared by this clonal progeny, indicating that extreme clonal selection had occurred early in the clonal development. Taking into account the frequency of somatic mutations and the clone size, it was evident that the responding cell population must have originated from a mutated, highly selected, and expanded population of cells existing before vaccination, i.e., memory B cells. The dominating heavy and light chains of the response were combined in a Fab that bound HibCP. It was shown that the shared heavy and light chain mutations increased the affinity for HibCP considerably, indicating that the clonal selection had been driven by affinity. Pre-existing memory cells in unvaccinated adults may explain several features of Ab responses to polysaccharide vaccines and may play a role in acquiring the ability to respond to pure polysaccharides during infancy.
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Afinidad de Anticuerpos , Subgrupos de Linfocitos B/inmunología , Vacunas contra Haemophilus/inmunología , Inmunoglobulina A/biosíntesis , Isotipos de Inmunoglobulinas/biosíntesis , Memoria Inmunológica/inmunología , Activación de Linfocitos/inmunología , Polisacáridos Bacterianos/inmunología , Adulto , Secuencia de Aminoácidos , Afinidad de Anticuerpos/genética , Subgrupos de Linfocitos B/metabolismo , Cápsulas Bacterianas , Secuencia de Bases , Diferenciación Celular/genética , Diferenciación Celular/inmunología , Células Clonales/inmunología , Células Clonales/metabolismo , Reordenamiento Génico de Cadena Pesada de Linfocito B , Reordenamiento Génico de Cadena Ligera de Linfocito B , Vacunas contra Haemophilus/administración & dosificación , Humanos , Esquemas de Inmunización , Inmunoglobulina A/genética , Inmunoglobulina A/metabolismo , Fragmentos Fab de Inmunoglobulinas/genética , Fragmentos Fab de Inmunoglobulinas/metabolismo , Isotipos de Inmunoglobulinas/genética , Isotipos de Inmunoglobulinas/metabolismo , Región Variable de Inmunoglobulina/genética , Región Variable de Inmunoglobulina/metabolismo , Memoria Inmunológica/genética , Activación de Linfocitos/genética , Masculino , Datos de Secuencia Molecular , Mutación/inmunología , Polisacáridos Bacterianos/administración & dosificación , Vacunas Conjugadas/administración & dosificación , Vacunas Conjugadas/inmunologíaRESUMEN
The expressed human kappa light chain gene repertoire utilized by healthy individuals was studied by two different single-sided specific PCR techniques to avoid bias for certain V genes. A total of 103 rearranged kappa sequences from peripheral blood mononuclear cells from healthy individuals were cloned from cDNA and assigned to the Vkappa and Jkappa germ-line genes with the closest overall homology. The use of cDNA rather than genomic DNA focused the analysis on activated B cells rich in mRNA. Accordingly, the sequences represented the applied repertoire and almost all were somatically mutated. V genes from the Jkappa-proximal duplication unit of the kappa locus were almost exclusively used. A total of 65% of the sequences could be assigned to four or five genes: A27 (humkv325), L6 (Vg), L2 (humkv328), and A3 and/or A19. N additions and P nucleotides were quite common and found in 32% and 21% of the sequences, respectively. Extended CDR3s more than nine residues in length were found in 18% of the sequences, and in 71% of cases this was due to insertion of an extra proline residue. This proline was usually explained from the germ-line sequences involved. These results are in good agreement with those of previous repertoire studies using potentially V-gene-biased techniques. Thus, it is clear that restricted V-gene usage, common N and P additions, and extended CDR3 regions are normal features and not, as has been claimed, characteristics of pathological autoantibodies.
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Genes de Inmunoglobulinas , Cadenas kappa de Inmunoglobulina/genética , Mutación , Autoanticuerpos/genética , Linfocitos B/inmunología , Linfocitos B/metabolismo , Células Cultivadas , Clonación Molecular , ADN Complementario/genética , Reordenamiento Génico , Variación Genética , Humanos , Leucocitos Mononucleares , Datos de Secuencia Molecular , Reacción en Cadena de la Polimerasa , Análisis de Secuencia de ADNRESUMEN
Restricted V region diversity is a key feature of Abs to many haptens and simple polysaccharides. Two possible mechanisms exist: 1) selection of many clonally unrelated B cells using very similar or identical VDJ and VJ rearrangements; and 2) selection of a heavily expanded progeny of few virgin B cells. How many virgin B cells eventually give rise to the total Ab response to a simple Ag is a fundamental immunologic question. In this report, we address this question in human adults by analyzing the rearranged VkappaJkappa genes of B cells responding to a single dose of the capsular polysaccharide of Haemophilus influenzae type b coupled to tetanus toxoid. We combined affinity purification of circulating vaccine-induced Ab-secreting cells with PCR amplification of cDNA followed by cloning and sequencing. Forty-eight and 42 kappa VJ gene transcripts were analyzed from two adults, respectively. Both individuals used extremely restricted repertoires with >90% of the cells using a single Vkappa gene rearranged to a single Jkappa gene. Despite the fact that the Ab responses engaged high numbers of Ab-secreting cells, analysis of the many shared, somatically acquired mutations showed that the majority of the cells originated from a common virgin B cell. Kinetic considerations implied that an extremely selected population of hypermutated memory B cells must have existed in these individuals before the first systemic immunization with the Ag. A possible role for the mucosal immune system in the priming and selection of these cells is proposed.
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Antígenos Bacterianos/inmunología , Linfocitos B/inmunología , Células Clonales/inmunología , Vacunas contra Haemophilus/inmunología , Haemophilus influenzae/inmunología , Memoria Inmunológica , Polisacáridos Bacterianos/inmunología , Adulto , Antígenos Bacterianos/biosíntesis , Antígenos Bacterianos/genética , Cápsulas Bacterianas , Secuencia de Bases , Femenino , Reordenamiento Génico de Cadena Ligera de Linfocito B , Genes de Inmunoglobulinas , Humanos , Región Variable de Inmunoglobulina/genética , Cadenas kappa de Inmunoglobulina/genética , Masculino , Datos de Secuencia Molecular , ARN Mensajero/genética , Alineación de Secuencia , Homología de Secuencia de Aminoácido , VacunaciónRESUMEN
Immunoglobulin gene polymorphisms are interesting because they reflect differences in the available antibody repertoire which may affect the susceptibility to specific infections. Until recently, the human V kappa gene, A18, was known as a nonfunctional gene only. In this study, we cloned and sequenced four apparently functional alleles and determined the gene frequencies in three well-defined populations: Danish Caucasians, eastern Greenland Eskimos and Mozambican blacks. The A18b allele that was recently described in Native American Navajos by Atkinson et al. was found in all three populations with gene frequencies of 8%, 45% and 23% in Caucasians, Eskimos and blacks, respectively. Conversely, the frequencies of the nonfunctional A18a allele were 92%, 55% and 57%. Further, three new A18 alleles, c, d, and e were found exclusively in blacks, among whom they had an total frequency of 19%. These data indicate that both the A18a and A18b alleles originated before the diversification of Africans and non-Africans 90,000 years ago, whereas the A18c, A18d and A18e alleles may have a more recent origin. The functionality of the A18b allele was documented by the demonstration of properly rearranged and somatically hypermutated A18b messenger RNA present in the blood lymphocytes of individuals carrying this allele. The expression clearly exceeded that of a known functional V gene, A2, indicating that functional A18 alleles contribute significantly to the available antibody repertoire. In this context, it is surprising that the functional A18b allele apparently has been negatively selected in the Caucasian population, among whom 85% completely lack a functional gene.