Serum inhibitory factors (SIF) in patients with acute and chronic hepatitis and their clinical significance

Serum inhibitory factors (SIF) were demonstrated in a follow-up study in eighteen patients with HBSAg-positive viral hepatitis, in nine patients with chronic persistent hepatitis (CPH) and in six patients with progressive viral hepatitis (CAH). In addition these factors were studied in fifteen patients with HBSAg-positive and HBSAg-negative CAH. SIF appeared during the incubation period up to 4 weeks before onset and disappeared in most instances within 4 weeks after onset of jaundice. Sera from patients with CPH showed no marked inhibitory activity when studied over a period of up to 3 years as compared to patients with a progressive course of hepatitis. The presense of SIF may depend upon persistence of virus, and may help to predict the development of chronic hepatitis.

[Change of the prevalent subtype of hepatitis B antigen in acute hepatitis B infections (author's transl)]

Subtyping of hepatitis B antigen (HBs Ag) in patients with acute hepatitis B revealed subtype ay in 75 percent while subtype ad was much more common in chronic hepatitis B infections: 81 percent of HBs Ag positive blood donors and 76 percent of patients with HBs Ag positive chronic aggressive hepatitis revealed subtype ad. In contrast to blood donors and chronic hepatitis patients, a change of the prevalent subtype was noted in acute hepatitis patients between 1970 and 1974. Before May 1972, subtype ad was found in 67 percent of patients, whereas later subtype ay dominated in 93 percent. An unequal distribution of subtypes between acute and chronic forms of hepatitis B infections has been explained by differences in the virulence of virus strains. Our results suggest that the higher prevalence of subtype ad in longterm carriers may be due to infection during an earlier time when subtype ad was also common in acute infections. The change of the prevalent subtype in acute infections may be attributed to differences in contagiosity rather than differences in virulence of virus strains.

[Humoral immune phenomena in acute and chronic viral hepatitis (author's transl)]

During HBAg positive acute viral hepatitis transitory antibodies of a low titer against smooth muscle, vascular endothelium, nuclei, and liver cell membrane antigens (polygonal pattern of immunofluorescence) occur. In HBAg positive chronic aggressive hepatitis, sometimes antibodies against nuclei or smooth muscle are associated with HBAg. Their occurrence heralds an unfavorable prognosis. High titer antibodies against nuclei and smooth muscle - a typical serology finding in lupoid chronic aggressive hepatitis - and mitochondrial antibodies have not been observed in a HBAg positive hepatitis. Subdividing chronic hepatitis in six different groups is possible with HBAg and antibodies. The predominance of histocompatability antigen HLA 8 in lupoid hepatitis and a lack of this leukocyte antigen in HGAg positive chronic aggressive hepatitis suggests that in the various forms of hepatitis, a different susceptability and capability for immune response towards microorganism is reflected. It is postulated that for course and outcome of hepatitis, the type of immune reaction plays a decisive role.

[Heterogenicity of mitochondrial antibodies (author's transl)]

Sera from 137 patients with mitochondrial antibodies were tested against two different mitochondrial antigens. The mitochondrial antibodies from patients with pseudo-lupus erythematosus (PLE antigen) reacted exclusively with antigen which sedimented on moving-zone centrifugation at a density of 1.10, and contained no antigenic activity when tested against sera from patients with primary biliary cirrhosis (PBC). Purified PBC antigen had no PLE antigen activity at a density of 1.19, and all sera from patients with autoimmune liver disease fixed complement with this fraction. Sera from 54 of 55 patients with PLE reacted with the antigen of the PLE-gradient fraction. But 71 patients with liver disease had no such uniform reaction: sera from 39 patients fixed complement only with the PBC fraction, whereas 32 reacted stimultaneously with both the 1.10 and 1.19 density gradient fraction. The latter pattern was especially found in patients with chronic active hepatitis in whom antibodies to smooth muscle and nuclei were frequently detected.

Non-organ-specific cytoplasmic antibodies detected by immunofluorescence

Appearances in the immunofluorescence test produced by mitochondrial antibodies associated with primary biliary cirrhosis (‘M’ fluorescence) are compared and contrasted with those of the cardiolipin fluorescent antibodies (‘CLF’) seen in patients with active secondary syphilis. The corresponding antigens are quite distinct but are both situated in the inner membrane of the mitochondria. A further structural connection between them is suggested by the selective staining with both antibodies of mitochondria engaged in high energy work and utilizing fatty acid pathways for energy production. Two other cytoplasmic autoantibodies are described. Both are thought to be of rare occurrence and could be absorbed-out with ribosomal subfractions of rat liver homogenates while mitochondria had no effect. The pathogenic role of all these non-organ-specific reactions is still unknown but they are thought to be stimulated by contact with viruses or other microorganisms.

Mitochondrial antibodies in primary biliary cirrhosis. IV. Significance of membrane structure for the complement-fixing antigen

The effect on the mitochondrial antigen of different agents known to influence the integrity and structure of membranes has been studied using quantitative complement fixation with autoantibodies from the serum of a patient with primary biliary cirrhosis. The susceptibility to proteolytic enzymes suggests that the antigen is a protein. Activity depends upon an association with phospholipids. Addition of phospholipids prevents loss of antigen during artificial ageing of mitochondria at 37°. Activity is lost after treatment with phospholipases or solvents which extract phospholipids. Antigen is also destroyed by surface active agents which dissociate the link with phospholipid but those which weaken bonds between phospholipids and hydrophobic molecules yield fragments of antigen-containing membrane structures which, nonetheless, still react with the mitochondrial autoantibody.

Mitochondrial antibodies in primary biliary cirrhosis. 3. Characterization of the inner-membrane complement fixing antigen

The mitochondrial inner-membrane autoantigen reacting with the serum of patients with primary biliary cirrhosis, was purified up to fifty-fold by centrifugal fractionation of sub-mitochondrial fragments obtained by hypotonic swelling and ultrasonication. Respiration and oxidative phosphorylation as well as swelling and contraction were not affected by the presence of the antibody and it could be shown that a number of readily extractable mitochondrial enzymes, and the components of the electron transport chain were not associated with the antigen. The highly purified antigen fraction, although having a vesicular ultrastructure with phospholipid composition characteristic of inner membranes, was nonetheless devoid of cytochrome oxidase activity. Although the exact location of the antigen on the inner membranes is not yet known, it can be physically dissociated from the components of the respiratory chain.

Mitochondrial antibodies in primary biliary cirrhosis. II. The complement fixing antigen as a component of mitochondrial inner membranes

The autoantibodies found in the sera of patients with primary biliary cirrhosis have been shown to react with a component of the mitochondrial inner membranes. Outer membranes were inactive. The purity of the inner and outer membrane fractions obtained by 2 different methods was assessed by electron microscopy and marker enzyme tests. Using negative-staining it was possible to visualize antibody binding to mitochondrial membranes. At high resolution it could be seen that the 90° particles on the cristal membranes were not involved in the reaction with antibody, but it was not possible to establish in the present studies the precise antigenic site upon the mitochondrial inner membranes.

Mitochondrial antibodies in primary biliary cirrhosis. I. Localization of the antigen to mitochondrial membranes

The antigen reacting with complement-fixing antibodies in the sera of patients with primary biliary cirrhosis was localized predominantly in the mitochondrial fraction of tissue homogenates obtained by differential centrifugation. Purified mitochondrial preparations had a high content of the antigen whereas purified lysosomes failed to fix complement with PBC sera. Analysis of a number of fractionation experiments showed a high correlation between antigen content and the mitochondrial enzyme succinic dehydrogenase in all fractions. There was much poorer correlation with lysosomal and micrososomal enzyme markers. The patterns of staining obtained with a fluorescein conjugate of IgG from a PBC patient closely paralleled those obtained with a histochemical method for the demonstration of succinic dehydrogenase, further confirming the mitochondrial localization of the antigen. Staining was brightest in cells containing mitochondria with well-developed cristae. Studies on mitochondria fragmented by osmotic lysis, hexane, lysolecithin, and ultrasound suggest that the antigen is associated with the mitochondrial inner membranes.