Clinical diagnosis in patients with smooth muscle antibodies. A study of a one-year material

A re-examination of patients with previously detected autoantibodies to smooth muscle

A group of patients which previously had been found to possess smooth muscle antibody (SMA) activity was re-examined for persistence of the autoantibody. The mean observation time was four years (range 0.5-9 years). Thirty out of 140 patients, who initially had SMA associated with rheumatic or other symptoms, had autoantibody activity at re-examination. Most were low in titer, and none of the 30 had developed chronic liver disease. Twenty-four patients with SMA at the first testing were analyzed because of liver pathology. Five had CAH at that time. SMA in low titer associated with liver pathology was a transient phenomenon. SMA in high titer combined with liver pathology seems to be a persistent condition with respect to both parameters, although no additional patients developed CAH between the first testing and re-examination.

Autoantibodies and serum immunoglobulins in chronic liver diseases

In a prospective consecutive study, 68 patients with various liver diseases and 67 control persons were examined for the occurrence of smooth muscle antibodies (SMA), antinuclear antibodies (ANA) and mitochondrial antibodies (MTA) of IgG, IgA and IgM class. A determination of serum immunoglobulins (S-IgG, S-IgA and S-IgM) was also performed. IgG-SMA in titres of greater than 80 occurred in 8 of 12 patients (67%) with hepatitis B antigen (HBag)-negative chronic active liver disease (CALD) and not in other diseases. Apart from one patient with primary biliary cirrhosis (PBC), IgG-ANA in titres of greater than 40 were likewise detected only in HBag-negative CALD (33%). The titres of IgG-SMA and IgG-ANA varied analogously with the biochemical liver parametres. There was a mutual exclusion between HBag and IgG-SMA/-ANA in titres of greater than 20, while IgM-SMA occured in titres of 80 in two patients with HBag-positive CALD. The incidence and titres of IgM-SMA and -ANA were not higher than in the controls. IgA-SMA and -ANA were detected only sporadically. The MTA demonstrated were of IgG PCLASS AND TITRES OF GREATER THAN 40 WERE FOUND ONLY IN PATIENTS WITH PBC (4 of 5). Som of the patients in all groups had an increased conenctration of one or more of the serum immunoglobulins. S-IgG levels were found to be significantly higher in CALD than in the other groups

Pathogenesis of autoimmune hepatitis

Autoimmune hepatitis (AIH) is an idiopathic disorder affecting the hepatic parenchyma. There are no morphological features that are pathognomonic of the condition but the characteristic histological picture is that of an interface hepatitis without other changes that are more typical of other liver diseases. It is associated with hypergammaglobulinaemia, high titres of a wide range of circulating auto-antibodies, often a family history of other disorders that are thought to have an autoimmune basis, and a striking response to immunosuppressive therapy. The pathogenetic mechanisms are not yet fully understood but there is now considerable circumstantial evidence suggesting that: (a) there is an underlying genetic predisposition to the disease; (b) this may relate to several defects in immunological control of autoreactivity, with consequent loss of self-tolerance to liver auto-antigens; (c) it is likely that an initiating factor, such as a hepatotropic viral infection or an idiosyncratic reaction to a drug or other hepatotoxin, is required to induce the disease in susceptible individuals; and, (d) the final effector mechanism of tissue damage probably involves auto-antibodies reacting with liver-specific antigens expressed on hepatocyte surfaces, rather than direct T-cell cytotoxicity against hepatocytes.

Specific liver autoreactivity in schistosomiasis mansoni

To investigate the possible involvement of autoimmune mechanisms in the development of hepatosplenic schistosomiasis (HSS), 234 patients with chronic Schistosoma mansoni infections were screened for a wide range of non-organ-specific autoantibodies as well as for antibodies reacting with the GOR peptide and with a liver-specific autoantigen, the hepatic asialoglycoprotein receptor (ASGP-R). Thirty-five (15.0%) were seropositive for antinuclear, smooth muscle or gastric parietal cell antibodies at low titres (< or = 1:80), and 15/176 (8.5%) had anti-GOR, all of whom had concomitant hepatitis C viral (HCV) infections. Anti-ASGP-R was found in 64 (27.4%) of the 234 patients at titres similar to those found in 18 untreated auto-immune hepatitis patients studied concurrently. Anti-ASGP-R seropositivity occurred significantly (P < 0.005) more frequently in patients with HSS (62/190, 32.6%) than in those with hepatointestinal schistosomiasis (2/44, 4.5%), but did not correlate with severity of liver disease or with the presence of the non-organ-specific autoantibodies. Anti-ASGP-R was found significantly (P < < 0.0005) less frequently in HSS patients who had had a splenectomy for portal hypertension (5/86, 5.8%) than in those who had not had a splenectomy (57/104, 54.8%). The findings suggest that liver-specific autoreactivity may play a role in the development of HSS.

Anti-actin antibodies in sera from patients with autoimmune liver diseases and patients with carcinomas by ELISA

Smooth muscle antibodies (SMA) were initially detected in sera of patients with chronic active hepatitis (CAH). Subsequently, their presence was demonstrated in a wide variety of other diseases. SMA are a mixture of antibodies directed towards different cytoskeletal antigens. Sera with high titers of anti-actin antibodies (AAA), a subgroup of SMA, are most frequently found among patients with autoimmune chronic active hepatitis (CAH) and, to a lesser extent, among patients with primary biliary cirrhosis (PBC) and other diseases. It is therefore established that AAA are a reliable marker to autoimmune CAH. The purpose of this study was to determine the titer of AAA in sera of patients with liver, autoimmune diseases and carcinomas, using the enzyme-linked immunoabsorbent assay (ELISA) method. The results were expressed as the optical density (OD) of the examined sera divided by the OD of a sera from a healthy control (presented as percentages +/- standard deviation). Sera of 33 patients with cirrhosis, nine patients with autoimmune CAH, fifteen patients with non-autoimmune CAH, eight patients with PBC, 30 patients with Sjogren's syndrome, 60 patients with SLE, 142 patients with carcinomas of different kinds, and 34 healthy donors were examined for the presence of AAA by ELISA. Statistically significant (P < 0.003) higher titers of AAA were detected in patients with autoimmune CAH (57 +/- 23%) compared with the control group and to other groups of diseases. AAA titers in non-autoimmune CAH were not significantly higher compared to the control group. High titers of AAA were detected in 67% of the patients with autoimmune CAH, as compared with other diseases in which only up to 13% of the patients exhibited AAA positivity.

CONCLUSION

existence of higher levels of AAA noted in 67% of the patients with autoimmune CAH with regard to other groups of diseases, emphasizes the value of AAA as sensitive and specific markers, capable of characterizing the patients with autoimmune chronic active hepatitis.

M-component with reactivity against actin associated with thrombotic thrombocytopenic purpura

A patient with a monoclonal B-cell disorder producing an M-component with antiactin activity is described. After more than 3 years of observations, the final diagnosis is not completely established, but a malignant lymphoproliferative process is evidently under evolution. On three occasions, she has presented with symptoms compatible with a thrombotic thrombocytopenic purpura-like syndrome, concomitant with an increase in paraprotein. A relationship between this autoantibody and the patient's symptoms is proposed. Steroids have so far had a beneficial effect on the symptoms.

Elevated levels of smooth muscle autoantibodies in patients with acromegaly

Screening of sera from patients with central nervous system (CNS) tumors for serum antibodies to tumor and normal tissue antigens revealed that the sera from a significant percentage of patients with pituitary adenoma demonstrated reactivity for smooth muscle antibodies (SMA) at a serum titer (1/25) at which other CNS tumors are devoid of this reaction. The sera were assessed by an indirect immunofluorescent antibody assay on fresh cryostat sections of rat kidney, liver, diaphragm, and stomach tissue. Absorption of SMA-positive sera with extracts containing smooth muscle tissue abolished the reaction. The overall incidence of SMA among patients harboring pituitary tumors was 30% (12/40). Assessment of the functional types of the tumor revealed a distinct predilection for such findings among patients with clinical acromegaly. Among patients with hypersecretion of growth hormone (CA) 90% (9/10) have SMA (both IgG and IgM type) whereas SMA was positive in only 10% (3/30) of corresponding group of patients with pituitary tumors resulting in hypercortisolemia or those that did not result in a hyperfunctional endocrine state.

Immunologic tests of value in diagnosis. 1. Acute phase reactants and autoantibodies

Acute phase reactants are nonspecific indicators of tissue necrosis and/or inflammation but may be helpful in determining activity of disease. Rheumatoid factor is likewise rather nonspecific, but its presence is helpful in predicting the course, severity, and complications of rheumatoid arthritis. Numerous antinuclear antibodies have been identified in collagen vascular diseases; perhaps the most specific association is between anti-Sm antibody and systemic lupus erythematosus. Anti-smooth-muscle and antimitochondrial antibodies can aid in differential diagnosis of liver disease, while antithyroid antibodies can perform a similar function in diffuse goiter. Anti-parietal-cell and anti-intrinsic-factor antibodies are quite specific for pernicious anemia.