Anti-F Actin Ab, IgA

Test Code: 575
CPT Codes: 83516
Methodology: EIA
Specimen Requirements: 1 mL serum, ambient, refrigerated or frozen
Turn Around Time: 3 – 5 Days
Special Instructions: None
Clinical Utilities: Anti-actin autoantibodies are the main component of what have been called smooth muscle antibodies (ASMA).  These antibodies display specificity towards the actin component of the cytoskeleton and are traditionally detected by indirect immunofluorescence utilizing thin sections of rodent liver, kidney or stomach as substrate.Anti-actin IgG antibodies are found in 52-85% of patients with AIH or chronic active hepatitis (CAH) and in 22% of patients with primary billiary cirrhosis (PBC).  Anti-actin antibodies have been reported, usually in low titers, in 3-18% of sera from the general healthy population.  Anti-actin IgG antibody positive patients were more prone to be unresponsive to corticosteroid therapy (16% vs. 4%) and were more prone to suffer liver failure (20% vs. 4%).

In contrast to anti-F-Actin IgG antibodies which are characteristic of patients with autoimmune hepatitis, anti-F-Actin IgA antibodies are clinically relevant to patients with celiac disease.  Recent studies have found that IgA antibodies to F-Actin show a strong correlation with the degree of intestinal villus atrophy present in celiac disease patients.  Anti-F-Actin IgA antibodies decrease following institution of a gluten-free diet and suggest measurement of these antibodies may have a role in monitoring gluten free diet compliance.