Background

Anti-Smooth-Muscle Antibody (ASMA) was discovered by Johnson in 1965. Antibodies in sera of patients who have chronic liver disease can attach to the smooth muscle of rat stomachs. These antibodies are found in conditions like malignancy, hepatitis, heroin use, and autoimmune liver diseases like primary biliary cirrhosis.

As per the study of Gabbiani, ASMA targeted actin after a platelet derived actin thrombosthenin A eliminated smooth muscle antibody activity in the sera of 5 patient who have chronic active hepatitis. Actin is a common, ubiquitous contractile protein. It can be present in non-muscle cells. Glomerular smooth-muscle antibody (SMA-G) and tubular smooth-muscle antibody (SMA-T) immunofluorescence staining pattern reacts with F-actin filamentous actin.

Immunologic detection

The IIF immunofluorescence is used to detect the ASMA. IFF is a standard method to detect ASMA. This includes a thin samples of rodent stomach, liver, or kidney of serum of patient. 1:20 or 1:40 dilution of serum of patient is used to screen. If it is present in the serum, antibodies are attached to smooth muscle antigen on the rodent tissue samples. These antibodies are seen by a fluorescein conjugated anti-immunoglobin Ab. It acts as a secondary antibody. The tissue is detected with a fluorescence microscope, and if staining is seen, it is positive. The serum of patient is titrated with dilution till immunofluorescence is not detected.

Indications/Applications

ASMA titer test is performed to evaluate the patients who have liver disease which is suspected to have autoimmune etiology. The clinical symptoms of patients may vary.

Asymptomatic patients with transaminitis

Overlap syndromes

Fulminant hepatic failure

Acute hepatitis

Chronic active hepatitis

Established cirrhosis

ASMA test is performed as a panel test to detect the etiology of liver diseases of the different symptoms like overlap syndromes.

ASMA test must be performed along with ancillary test to evaluate the dysfunction of liver because of AIH-1. Other tests like immunoglobulin level test, anti-LKM test, ANA test, and anti-LC1 test.

Symptoms of autoimmune diseases are like:

Joint pain

Fatigue

Abdominal pain

Jaundice

Loss of appetite

Dark color urine

Light color stool

Skin diseases like rash, acne, psoriasis

Reference Range

The normal range of ASMA test is less than 1:20. There is no variation in sex or race to the results.

Interpretation

Negative result of ASMA test is seen in health individuals. Positive result of ASMA is seen in conditions like:

Hepatitis B

Autoimmune hepatitis type 1

Hepatitis C

Primary sclerosing cholangitis

Overlap syndromes

Primary biliary cirrhosis

As per the study of Alvarex, a scoring of (AIH-1) autoimmune hepatitis type 1 was given. Negative titer has 0 points. 1:40 titer has 1 point, 1:80 titer has 2 points, and more than or equal to 1:80 titer has 3 points. A good diagnosis is made by a score of more than 15 and a score of 10 to 15 suggested a diagnosis of AIH-1.

As per the study of Czaja, a new scoring was introduced. More than or equal to 1:40 titer has 1 point, and more than or equal to 1:80 titer has 2 points. A good diagnosis is more than or equal to 7, and a possible diagnosis is 6.

Collection And Panels

Sample: blood or serum

Sample collection method: Routine venipuncture

Sample collection container: Red top vacutainer

Considerations: there is no need for any prior preparation to perform this test. There is no contraindications for the ASMA test.

Sample storage instructions: Samples can be stored in refrigerator a 2 to 8 °C. Sample is stable for 1 to 2 weeks.

Panels:

Autoimmune liver disease panel includes ASMA. Other tests are included ANA test, anti-LKM test, AMA test.

References