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Cardiac conducting tissue antibodies (CCTA) were detected, using indirect immunofluorescence, in 8 (25%) out of 32 sera from patients with progressive systemic sclerosis (PSS) and in 39 (35%) out of 110 with rheumatoid arthritis (RA). Conduction abnormalities, namely right bundle branch block, were present in 19 (59%) of the PSS patients and in 37 (32%) of the RA cases. No significant correlation was found between the prevalence of CCTA and conduction abnormalities in PSS patients, while this was present in RA patients (p less than 0.001). CCTA were always negative in 18 patients with systemic lupus erythematosus and were found in one out of 8 cases with Sjögren's syndrome, also positive for rheumatoid factor without clinical RA. These data suggest that CCTA are evoked when involvement of cardiac conducting tissue (as in RA) or working myocardium (as in PSS) is present. Whether CCTA should be mainly regarded as an expression of the immunological derangement underlying these pathological conditions or whether they are secondary to myocardial tissue damage, must still be clarified.

Two immunofluorescence procedures to evaluate antinuclear antibodies were compared in a series of 221 patients with chronic liver disorders of various aetiologies. The use of HEp-2 cells allowed us to discriminate with more confidence between the homogeneous and speckled patterns, to show the presence of associated patterns in the same serum, and, above all, to identify two specificities, unrecognizable on tissue sections. The anticentromere antibody was found in 10% of cases of primary biliary cirrhosis and occasionally in other conditions; the antibody staining multiple nuclear dots was strictly confined to primary biliary cirrhosis (17%). With the exception of autoimmune chronic active hepatitis the prevalence of antinuclear antibodies increased in all groups, particularly in primary biliary cirrhosis. Homogeneous antinuclear antibody was associated by both immunofluorescence procedures with autoimmune chronic active hepatitis. The multiple nuclear dot antinuclear antibody turned out to be an additional marker of primary biliary cirrhosis, helpful for the positive diagnosis of primary biliary cirrhosis in a proportion of cases negative for antimitochondrial antibody. Absorption experiments showed that multiple nuclear dot and antimitochondrial antibody are antigenically distinct. Moreover, multiple nuclear dot antinuclear antibody was associated with the finding of a dry Schirmer's test.

R2 anti-reticulin antibody was detected in 15 of the 9,500 serum samples examined (0.16%) from a mixed hospital population. The antibody titre varied from 1:40 to 1:320, and the R2 was of the IgG class in 13 of the 15 positive samples. All the 15 serum samples with R2 were negative on human liver, confirming the lack of cross reaction of this antibody. The reactivity of R2 was not absorbed by soluble fractions of type I collagen, showing that this antibody is not directed against this antigen. R2 was confined to two groups of pathological conditions: connective tissue and digestive tract diseases. Four of 15 patients with R2 had rheumatoid arthritis and in two of these four cases the antibody was of the IgA class.

The ultrastructural morphology of mechanically and enzymatically isolated hepatocytes was compared. Plasma membrane integrity was evaluated by electron microscopy, both in the absence and in the presence of ruthenium red, which stains cell coat glycoproteins and makes it possible to identify even partially permeable cells, and by indirect immunofluorescence using experimental antibodies directed against epithelial submembranous components (prekeratin, actin). In order to evaluate the antigenic integrity of the hepatocellular plasma membrane after the isolation procedures, an immuno-electronmicroscopical technique (Staph. pA-colloidal gold) was applied using the IgG fraction from two liver-kidney microsomal antibody (LKM) positive sera, known to react with both plasma membranes and smooth endoplasmic reticulum (SER). Enzymatic procedure made it possible to isolate hepatocytes with a good preservation of both plasma membranes and subcellular organelles. Ruthenium red staining was confined to plasma membranes, thus indicating the preservation of both cell-coat glycoproteins and plasma membrane. Most cells were negative after exposure to experimental antibodies. After exposure to LKM positive sera colloidal gold was strictly confined to the plasma membrane. On the other hand, mechanically isolated hepatocytes showed wide interruptions of the plasma membrane and gross alterations of subcellular organelles. Most cells were stained by ruthenium red, thus confirming the plasma membrane permeability. In addition, a linear peripheral positivity was found in the vast majority of the cells tested with anti-prekeratin and anti-actin antibodies. LKM-colloidal gold complexes were found at the level of both residual plasma membrane and SER.(ABSTRACT TRUNCATED AT 250 WORDS)

Antibodies to dietary antigens (ovalbumin, beta-lactoglobulin, casein) have been detected by a micro-ELISA test in 47-50% of serum samples from patients with alcoholic liver cirrhosis, in 27-36% with non-alcoholic cirrhosis (HBV-related, autoimmune and primary biliary) and in 50-70% of cirrhotic patients with portacaval shunt. Dietary antibodies were mainly confined to the IgA class (90%). In patients with chronic active hepatitis dietary antibodies showed a low positivity (11%), similar to that of subjects with alcohol abuse without liver injury and of healthy subjects. Dietary antibodies were significantly associated with portal hypertension (evaluated on the presence of esophageal varices and/or ascites) both in alcoholic and non-alcoholic cirrhosis. The absence of dietary antibodies in the duodenal juice of cirrhotic patients positive for serum antibodies confirms that the intestinal mucosa is normal or slightly altered in liver cirrhosis. Unlike cirrhotics, untreated celiac patients showed a high prevalence of dietary antibodies also in the duodenal juice (55%).

Antibodies to gliadin (AGA), detected in jejunal juice by immunofluorescence and enzyme-linked immunosorbent assay, have been found in 13 of 15 (87%) children with untreated coeliac disease. Jejunal AGA were also positive in 6 of the 9 (67%) coeliac children on gluten challenge, while they were consistently negative in coeliac children on a gluten-free diet and in controls. Jejunal AGA were always of immunoglobulin A (IgA) class, associated with IgM in some cases. Moreover, the presence of IgA AGA in jejunal juice was strictly related to the severity of intestinal damage. These data suggest that IgA AGA, detected in jejunal juice are synthesized from gut mucosa and are markers of its abnormal function. Like AGA, antibodies to milk and egg proteins were only found in jejunal juice of coeliac patients with flat intestinal mucosa, but their prevalence was significantly lower than that of AGA.

R1 reticulin antibodies were found in sera from patients with childhood celiac disease (CCD). Although the overall sensitivity of R1 in the diagnosis of CCD was relatively low (16/43 = 37%), when only those cases in an active phase of the disease were considered, the sensitivity increased (16/24 = 67%). In spite of its low sensitivity, the R1 assay did show a high degree of specificity, as this antibody was not found in children with post-enteritis syndrome or in healthy controls. R1 antibodies, when found in active CCD, always turned out to be positive when tested on human liver as substrate. While this fact did not enhance the sensitivity of the test, it strengthened its specificity, since R1, found in pathological conditions other than CCD, was nearly always negative on human tissue. Although the R1 reticulin antibody test cannot replace jejunal biopsy in the diagnosis of CCD, its assay, particularly on human liver as substrate, can be considered a useful tool in the screening of celiac patients.

Antibodies to gliadin, searched for by indirect immunofluorescence and a micro-ELISA, were detected in 16 (64%) of 25 sera from patients with adult coeliac disease and in 13 (45%) of 29 with dermatitis herpetiformis. Although the sensitivity of the two tests was relatively low in the whole groups, it increased when only cases with severe jejunum abnormalities were considered (93% for coeliac disease and 81% for dermatitis herpetiformis). A significant correlation was found between antigliadin antibodies and the severity of jejunum damage in both diseases. Moreover, most coeliac and dermatitis herpetiformis patients with antigliadin antibodies were on normal diet. The specificity of the tests was 100% for the immunofluorescence and fairly good for the micro-ELISA, as only 5 (11%) of the 46 disease control patients (Crohn's disease, ulcerative colitis) were positive for antigliadin antibodies. R1-reticulin antibody test was equally specific but less sensitive in both groups. We conclude that antigliadin antibodies are useful in the diagnosis of patients with active adult coeliac disease and dermatitis herpetiformis with gluten-sensitive enteropathy. Moreover, the two tests make it possible to monitor the compliance to gluten-free diet in both diseases.

Antibodies to gliadin (AGA) were found in 77 (94%) of 82 sera from patients with active coeliac disease (untreated and after gluten challenge). Although IgG AGA had a higher nosological sensitivity than IgA AGA (88% versus 67%), their nosological specificity was lower than that of IgA antibodies (87% versus 100%). The sensitivity of antibodies to casein, beta-lactoglobulin, and ovalbumin in active coeliac disease varied from 36% to 48% without significant difference between IgG and IgA antibodies. IgG and IgA antibodies to milk and egg proteins showed a specificity similar to that of AGA, although some IgA antibodies other than AGA were found in disease controls (Crohn's disease, ulcerative colitis, post-enteritis syndrome).

Antibodies to gliadin, detected by immunofluorescence (IFL-AGA) and ELISA (ELISA-AGA), have been found in 68 of 71 (96%) sera from children with active celiac disease. AGA of IgA class were confined to celiac disease on normal diet and after gluten challenge, as all the antibodies, found in children on gluten free diet (40%) and in control gastroenterological diseases (20%), were of IgG class. Sera from 175 first-degree relatives of our celiacs were also screened for AGA. IFL-AGA were positive in 13 (7%) and ELISA-AGA in 27 cases (15%). Antibodies were of IgA class in 13 relatives (7%). A celiac's asymptomatic sister, selected for jejunal biopsy only on the basis of IgA AGA positivity, showed subtotal villous atrophy. Although AGA cannot replace jejunal biopsy in the diagnosis of celiac disease, they can be regarded as useful tools in the screening of gluten sensitive enteropathy. Moreover, as a positive IgA AGA test is closely related to the active phases of celiac disease, their research can be useful both to evaluate the effect of gluten free diet and to establish when a new biopsy is appropriate after gluten challenge.