RESUMO
OBJECTIVES: To report on a novel immunofluorescence pattern specifically associated with antibodies to SS-A/Ro. METHODS: A novel immunofluorescence pattern, herein designated SS-A/Ro pattern, was characterized as myriad discrete fine speckles throughout the nucleus. Eighty-six sequential samples presenting the SS-A/Ro pattern and 64 samples presenting non-SS-A/Ro nuclear fine speckled pattern at the ANA-HEp-2 routine were screened for SS-A/Ro reactivity. Conversely, 48 samples with known reactivity to 60kDa SS-A/Ro, 13 samples with exclusive reactivity to 52kDa SS-A/Ro, and 48 SS-A/Ro-negative samples were analyzed for the ANA-HEp-2 pattern. RESULTS: Eighty-five of the 86 samples (98.8%) presenting the SS-A/Ro pattern and 15 of the 64 (23.4%) samples with non-SS-A/Ro fine speckled pattern reacted with 60kDa SS-A/Ro. Conversely, 44 (91.6%) of 48 samples with known reactivity to 60kDa SS-A/Ro presented the SS-A/Ro pattern and four (8.4%) presented non-SS-A/Ro fine speckled pattern. None of the 48 anti-SS-A/Ro-negative samples and none of anti-52kDa SS-A/Ro-positive samples yielded the SS-A/Ro pattern. This immunofluorescence pattern was observed in different commercial HEp-2 cell slides and in homemade HEp-2 cell slides. CONCLUSIONS: The SS-A/Ro pattern belongs to the group of immunofluorescence patterns that hold strong association with the respective autoantibody specificities, such as those associated with CENP-F and NuMA-1. The identification of the SS-A/Ro pattern at the ANA-HEp-2 screening routine shall lead to specific tests for the identification of anti-SS-A/Ro antibodies.
Assuntos
Anticorpos Antinucleares/imunologia , Autoanticorpos/imunologia , Núcleo Celular/imunologia , Imunofluorescência/métodos , Anticorpos Antinucleares/química , Autoanticorpos/metabolismo , Western Blotting , Linhagem Celular Tumoral , Núcleo Celular/metabolismo , Ensaio de Imunoadsorção Enzimática , Humanos , Peso Molecular , Reprodutibilidade dos TestesRESUMO
BACKGROUND: Cajal bodies (CB) are distinct sub-nuclear domains rich in small nuclear ribonucleoprotein particles (snRNPs); they are involved in pre-mRNA processing. Lupus erythematosus (SLE) is an autoimmune disease characterized by autoantibody production against different nuclear molecules, including those involved in pre-mRNA processing. The aim of the present investigation is to assess the presence of anti-CB autoantibodies in a cohort of SLE sera. MATERIAL/METHODS: Antinuclear antibodies (ANA) were screened by indirect immunofluorescence in a batch of 190 sera from patients who met the ACR criteria for SLE classification; fine specificity was determined by Western blot using HEp-2 cells or rat hepatocyte extracts purified by ion exchange chromatography. RESULTS: Four sera had anti-Cajal body (CB) autoantibodies. Interestingly, all of these patients had intermittent extensive oral and esophageal ulceration. The autoantibodies to CB were of the IgG class, and by Western blot these sera had reactivity against an 80 kDa protein (coilin) associated with Sm proteins. CONCLUSIONS: Anti-CB autoantibodies constitute an uncommon specificity of SLE; therefore it seems that anti-CB antibody specificity is associated with extensive mucous ulceration.
Assuntos
Autoanticorpos/química , Corpos Enovelados/química , Corpos Enovelados/imunologia , Lúpus Eritematoso Sistêmico/imunologia , Adolescente , Adulto , Animais , Anticorpos Antinucleares/química , Western Blotting , Linhagem Celular , Cromatografia , Cromatografia por Troca Iônica , Estudos de Coortes , Feminino , Técnica Indireta de Fluorescência para Anticorpo , Hepatócitos/metabolismo , Humanos , Imunoglobulina G/química , Masculino , Pessoa de Meia-Idade , Estrutura Terciária de Proteína , RNA Mensageiro/metabolismo , RatosRESUMO
The ability of affinity purified anti-52 kDa Ro/SSA antibody from patients without obstetric history of neonatal lupus to cause heart block using an experimental model was investigated. IgG-enriched fractions from sera of 20 systemic lupus erythematosus (SLE) and one Sjögren's syndrome (SS) all positives for anti-Ro/SSA antibodies as detected by CIE, were perfused on isolated whole rabbit hearts. Only six (29%) samples induced A-V block, five of them presenting low anti-Ro/SSA titre. All of them recognized the 52 kDa isoform on ELISA whereas only one had a concomitant binding to the 60 kDa protein. Moreover, affinity purified antibodies from two sera previously known to induce A-V block were obtained by affinity chromatography using a column containing the full-length 52 kDa Ro/SSA fusion protein. Paired eluate and effluent devoid of anti-52 kDa activity from the same patient were individually perfused in whole hearts. The ability to cause cardiac blockade was restricted to the affinity anti-52 kDa eluates. In addition, anti-52 kDa eluates from three IgG fractions that primarily failed to induce blockade remained ineffective. The present study has added to our knowledge that affinity anti-52 kDa Ro/SSA antibodies from mothers with healthy infants are capable of causing in vitro cardiac conduction disturbances. A prospective follow up of these patients will better delineate the clinical usefulness of this experimental model.