Easy recognition and high autoimmune hepatitis specificity of smooth muscle antibodies giving an actin microfilament immunofluorescent pattern on embryonal vascular smooth muscle cells.

Smooth muscle antibodies (SMA) with anti-microfilament actin (MF-SMA) specificity are regarded as highly specific markers of type 1 autoimmune hepatitis (AIH-1) but their recognition relying on immunofluorescence of vessel, glomeruli, and tubules (SMA-VGT pattern) in rodent kidney tissue, is restricted by operator-dependent interpretation. A gold standard method for their identification is not available. We assessed and compared the diagnostic accuracy for AIH-1 of an embryonal aorta vascular smooth muscle (VSM) cell line-based assay with those of the rodent tissue-based assay for the detection of MF-SMA pattern in AIH-1 patients and controls. Sera from 138 AIH-1 patients and 295 controls (105 primary biliary cholangitis, 40 primary sclerosing cholangitis, 50 chronic viral hepatitis, 20 alcohol-related liver disease, 40 steatotic liver disease, and 40 healthy controls) were assayed for MF-SMA and SMA-VGT using VSM-based and rodent tissue-based assays, respectively. MF-SMA and SMA-VGT were found in 96 (70%) and 87 (63%) AIH-1 patients, and 2 controls (P < 0.0001). Compared with SMA-VGT, MF-SMA showed similar specificity (99%), higher sensitivity (70% vs 63%, P = ns) and likelihood ratio for a positive test (70 vs 65). Nine (7%) AIH-1 patients were MF-SMA positive despite being SMA-VGT negative. Overall agreement between SMA-VGT and MF-SMA was 87% (kappa coefficient 0.870, [0.789-0.952]). MF-SMA were associated with higher serum γ-globulin [26 (12-55) vs 20 g/l (13-34), P < 0.005] and immunoglobulin G (IgG) levels [3155 (1296-7344) vs 2050 mg/dl (1377-3357), P < 0.002]. The easily recognizable IFL MF-SMA pattern on VSM cells strongly correlated with SMA-VGT and has an equally high specificity for AIH-1. Confirmation of these results in other laboratories would support the clinical application of the VSM cell-based assay for reliable detection of AIH-specific SMA.

Autoimmune Hepatitis: An Unusual Presentation.

Autoimmune hepatitis (AIH) is a chronic inflammatory liver disease that occurs in a bimodal age distribution in the second and fifth-sixth decade of life. The disease is more prevalent in females and presents with variable clinical manifestations ranging from being asymptomatic to acute liver failure. AIH is often overlooked and not worked up in elderly patients who present with liver failure. This can lead to increased morbidity and mortality in elderly patients. AIH should be considered as a differential diagnosis in patients who present with elevated transaminases regardless of age or gender as early recognition and treatment leads to improved outcomes. In this article, we present a unique case of AIH in a male patient in his eighth decade of life who presented with acute liver failure without any obvious cause and had no history of autoimmune diseases.

Significance of smooth muscle/anti-actin autoantibodies in celiac disease / Significado de los anticuerpos anti-músculo liso/anti-actina en la enfermedad celíaca

BACKGROUND/AIM: Smooth muscle antibody (SMA) specific for the protein actin, a major component of the cytoskeleton of epithelial cells, is one of the most prevalent non-organ specific autoantibodies in the serum of celiac disease (CD) patients. Our aim was to explore the clinical relevance of the presence of IgA type anti-actin antibody (AAA) and SMA in a series of patients with CD. METHODS: We evaluated frozen serum samples collected at diagnosis from 92 adult patients with CD and 52 control individuals in whom CD was excluded. Patients were re-evaluated a median time of 5 yr after treatment. IgA type AAA was detected using a modified commercial ELISA assay and IgA SMA was detected using indirect immunofluorescence on primate esophagus substrate. RESULTS: At diagnosis, samples from CD patients had significantly higher AAA values than controls (p<0.00001). While all active CD patients had serum AAA values over the cut-off for healthy controls, we observed a very significant reduction of these antibodies after treatment (p>0.0001). AAA had a highly significant correlation with both, tissue, transglutaminase (r=0.62) and antigliadin (r=0.60, p<0.00001) antibodies as well as the severity of the intestinal injury (p<0.05). SMA was detected in sera of 35 consecutive CD patients. At diagnosis, SMA positive patients had significantly higher values of AAA (p<0.0002), increased number of autoimmune disorders (p<0.04), delayed menarche (p<0.04), lower hemoglobin levels (p<0.01), increased fecal a-I antitrypsin clearance (p<0.01) and more severe diarrhea (p<0.06). We also detected a trend to more severe complications at follow-up (p=0.059). CONCLUSIONS: Based on our findings we suggest that the presence of increased IgA AAA serum levels is a highly sensitive marker of the disturbed architecture of intestinal epithelial cells of CD patients with a potential relevance to diagnosis and follow-up. The presence of SMA seems to define a distinct subset of CD patients with ...

Introduccion/objetivo: El anticuerpo anti-musculo liso (SMA) dirigido contra la proteína actina, un componente mayor del citoesqueleto de las células epiteliales, es el anticuerpo no-órgano específico más prevalente en enfermedad celíaca (EC). Nuestro objetivo fue explorar la importancia clínica de los anticuerpos anti-actina (AAA) y SMA en una serie de pacientes con EC. Métodos: Evaluamos 92 muestras serológicas de pacientes celíacos adultos recolectadas al momento del diagnóstico y la de 52 individuos controles no celíacos. Los pacientes fueron re-evaluados luego de un tiempo medio de 5 años en tratamiento. Evaluamos AAA tipoIgA mediante ELISA empleando un equipo commercial modificado y SMA IgA por inmunofluorescencia indirecta sobre sustrato de esófago de mono. Resultados: Al momento del diagnóstico, los pacientes celíacos tuvieron valores de AAA significativamente más elevados que los controles (p<0.00001). Todos los pacientes con EC activa presentaron niveles de AAA por encima del valor de corte determinado para el grupo control sano y se evidenció una reducción significativa de los nivelesluego del tratamiento (p>0.0001). Los AAA presentaron una correlación significativa con los anticuerpos anti-transglutaminasa tisular (r=0.62) y anti-gliadina (r=0.60) (p<0.00001), de igual modo que con la severidad del daño intestinal (p<0.05). Al momento del diagnóstico, se detectó SMA en el suero de 35 pacientes no controles. Los pacientes SMA positivos tuvieron valores significativamente mayores de AAA (p<0.002), un incremento del número de enfermedades autoinmunes asociadas (p<0.04), menarca tardía (p<0.04), niveles bajos de hemoglobina (p<0.01), incremento del clearance de a-1 antitripsina fecal (p<0.01) y mayor severidad de la diarrea (p<0.06).En ellos se evidenció una tendencia al desarrollo de complicaciones más severas durante el seguimiento (p=0.059). Conclusiones: Sugerimos que la presencia de un valor sérico aumentado de AAA tipo IgA...