Frequency and significance of antibodies to actin in type 1 autoimmune hepatitis

Abstract

tionally, multiple reactivities can be present concurrently in Antibodies to actin have been proposed as diagnostic the same patient. 10,11markers for type 1 autoimmune hepatitis. Our aims were Recent studies have suggested that anti-actin have specito determine 1) if testing for antibodies to actin is supeficity for autoimmune liver disease, 12-14 and they have been rior to testing for smooth muscle antibodies (SMA); 2) if advocated as better markers for autoimmune hepatitis than these antibodies identify patients with distinctive clini-SMA. 4,15,16 Indeed, the designation, ''anti-actin hepatitis,'' has cal features; and 3) if the production of antibodies to already been used to describe the condition. 16 The SMA found actin is associated with genetic risk factors for autoimin patients with viral infections, including viral hepatitis, are mune hepatitis. Sera from 99 patients with type 1 autoreactive mainly against non-actin cytofilaments (intermediimmune hepatitis were tested. The frequencies of HLA ate filaments), whereas the SMA described in infectious B8, DR3, DR4, and A1-B8-DR3 in patient subsets were compared with those in 80 normal subjects. Seventy-mononucleosis are reactive mainly against tubulin. 4,17 In conthree patients (74%) had antibodies to actin. Antibodies trast, the SMA in autoimmune hepatitis are typically reactive to actin were found more commonly in patients with against actin, 4,15 and this reactivity is either absent or infre-SMA than in patients without them (86% vs. 7%, P õ quent in other chronic liver diseases. 15,[17][18][19] Not all patients .0001). Screening only for antibodies to actin and antinu-with autoimmune hepatitis and SMA, however, have anticlear antibodies (ANA) failed to establish the diagnosis actin, and the frequency of actin immunoreactivity may be of autoimmune hepatitis in 5 patients. Patients with an-as low as 38% in such patients. 15,20 These observations sugtibodies to actin were younger than seronegative pa-gest that anti-actin determinations can enhance diagnostic tients. They were also more commonly DR3-positive specificity, but at a reduced sensitivity when compared with than normal subjects and more frequently B8-positive conventional SMA screening. The advantages of a more prethan patients with non-actin-associated SMA (49% vs. cise diagnosis by anti-actin testing have not been weighed 0%, P Å .004). Only patients with antibodies to actin died against the disadvantages of a missed diagnosis. of liver failure (6% vs. 0%), and 10 of 11 patients requiring Subclassifications of autoimmune hepatitis have been proliver transplantation were seropositive for these anti-posed based on immunoserological findings.21,22 Differentiabodies. Indeed, death and liver transplantation occurred tion of patient subsets by their seropositivity for SMA and/ more frequently in these patients than in actin-negative or ANA or antibodies to liver/kidney microsome type 1 has patients with ANA (19% vs. 0%, P Å .03). We conclude identified individuals who have distinctive clinical, labor...

Type 1 Autoimmune Hepatitis in Taiwan: Diagnosis Using the Revised Criteria of the International Autoimmune Hepatitis Group

“…A low positive rate of SMA tests (18%) was noted in our study. A high prevalence rate of SMA in AIH type 1 has been reported in Western countries [22,23]. On the other hand, a low prevalence of SMA was also reported in other Asian countries such as Japan and Singapore.…”

Autoantibody-Negative Autoimmune Hepatitis

“…Whereas SMA can occur without anti-actin in 14% of patients with classical autoimmune hepatitis and be the sole marker of the disease in 5% [11], anti-actin is rarely (if ever) discovered alone [11,143]. Accordingly, anti-actin are unlikely to further characterize patients with autoantibody-negative autoimmune hepatitis.…”

“…Antibodies to actin have high specificity for classical autoimmune hepatitis [15,17,20], but their assay has not been standardized [12,15,[17][18][19][137][138][139][140][141][142] and anti-actin are typically concurrent with SMA [11,17,18,143]. Whereas SMA can occur without anti-actin in 14% of patients with classical autoimmune hepatitis and be the sole marker of the disease in 5% [11], anti-actin is rarely (if ever) discovered alone [11,143].…”

“…One or more of these antibodies are also commonly present when the other less typical serological markers are detected [23]. The presence of a non-standard serological marker as the sole manifestation of autoimmune hepatitis is an unusual occurrence [11,13,[30][31][32][33]. The universal availability and superior sensitivity of assays for ANA, SMA, and anti-LKM1 for autoimmune hepatitis justify their use as the first-line testing battery [1,10].…”

“…Antinuclear antibodies (ANA), smooth muscle antibodies (SMA), and antibodies to liver kidney microsome type 1 (anti-LKM1) characterize most cases of autoimmune hepatitis [10], and they constitute the conventional serological markers of the disease [1]. Other autoantibodies that support the diagnosis are typically investigational or non-standard serological tests, and they include antibodies to actin (anti-actin), soluble liver antigen (anti-SLA), liver cytosol type 1 (anti-LC1), asialoglycoprotein receptor (anti-ASGPR), and uridine diphosphate glucuronosyltransferases (anti-UGT) [11][12][13][14][15][16][17][18][19][20][21][22][23].…”