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Hepatitis B virus associated DNA polymerase activity, hepatitis b surface antigen (HBsAg), and serum aspartate aminotransferase were followed in 21 patients with chronic active hepatitis while immunosuppressive therapy (prednisone +/- azathioprine) was being withdrawn. In every case, DNA polymerase activity fell within 6-10 wk of decreasing treatment and became undetectable in 8 patients. This was usually accompanied by a fall in HbsAg titer and a transient rise in serum aspartate aminotransferase activity. Four additional patients with previously untreated HbsAg positive chronic active hepatitis were placed on prednisone for 12 wk. There was a rise in DNA polymerase activity and HBsAg titer with a fall in serum aspartate aminotransferase values during treatment. Upon discontinuing therapy, DNa polymerase activity fell dramatically in all 3 patients who completed their course of prednisone and became undetectable in 1. These findings suggest that immunosuppressive therapy has a potentiating effect on hepatitis B viral replication in patients with chronic active hepatitis.

Stable E-rosette forming cells from peripheral blood of patients with acute type B hepatitis and from human thymus were compared with respect to buoyant density and FclgG receptors to stable E-rosette forming lymphocytes generated during culture of normal peripheral blood lymphocytes with concanavalin A. Stable E-rosette forming lymphocytes from patients were distributed in the same high density region of discontinuous bovine serum albumin density gradients as thymus stable E-rosette forming cells but thymus cells did not have FclgG receptors. 5-21% of normal peripheral blood lymphocytes formed stable E-rosettes after culture with concanavalin A but they were found in all densilty fractions. 6-29% of these lymphocytes had receptors for FclgG. The ability to form stable E-rosettes may be a marker for a subset of peripheral blood lymphocytes able to suppress immunological responses.

Lymphocytes forming E-rosettes with sheep erythrocytes which do not disintegrate at 37 degrees C have been demonstrated in increased numbers in peripheral blood of patients with acute type B hepatitis (6--20% of lymphocytes) and with HBsAg negative active chronic hepatitis (9--28% of lymphocytes). They were not increased in patients with HBsAg positive active chronic hepatitis. Such lymphocytes were adherent to nylon wool and a large proportion of them had FcIgG receptors (21--69%). These are properties of a subpopulation of T lymphocytes having suppressor function.

A virus given the name ground squirrel hepatitis virus (or GSHV), with many of the unique characteristics of human hepatitis B virus (HBV), has been found in Beechey ground squirrels in northern California. Common features include virus morphology, viral DNA size and structure, a virion DNA polymerase that repairs a single-stranded region in the viral DNA, crossreacting viral antigens, and persistent infection with viral antigen continuously in the blood. Although similar, GSHV and HBV Are not identical. The ground squirrel virion has a slightly greater diameter, the viral surface antigens crossreact only partially and, thus, are not identical, and GSHV DNA has two restriction endonuclease EcoRI cleavage sites in contrast to the single site in HBV DNA. Thus, GSHV is a member of the virus group that includes HBV and the virus recently found in woodchucks in the eastern United States and named woodchuck hepatitis virus. It is not yet known how closely the ground squirrel and woodchuck viruses are related.

In an uncontrolled trial, 29 patients with chronic hepatitis B virus infection were treated with 93 courses of adenine arabinoside at doses ranging from 2.5 to 15 mg/kg per day. Most patients were treated concomitantly with human leukocyte interferon. Significant, but transient, neurotoxicity was seen with adenine arabinoside therapy in 44% of all courses. Manifestations of toxicity were mainly neurological and ranged from pain syndromes to tremors and, rarely, seizures. Suppression of numbers of lymphocytes was also noted. All effects were reversible with time. The extent of toxicity was dependent upon the dosage of adenine arabinoside. Treatment with interferon appeared to potentiate the occurrence of toxicity with adenine arabinoside. Arabinofuranosylhypoxanthine serum levels increased in a dose-dependent manner and tended to accumulate in interferon-treated hepatitis patients during a course of therapy. Elevated blood levels and drug accumulation were associated with toxicity in a significant fashion. Human leukocyte interferon was administered to 38 patients in 113 separate courses. Interferon side effects were rapidly reversible upon cessation of therapy. These included initial fever, myalgias, and hair loss as well as suppression of granulocytes, platelets, and lymphocytes in the blood.

Three patients with HBsAg-positive and DNA-polymerase-positive chronic hepatitis were treated with increasing dosages of intravenous acyclovir. A fall in DNA polymerase activity was seen with all courses of acyclovir but no dose-response relationship was evident. In only one patient did DNA polymerase fall to zero where it has remained for five months. Two out of 10 courses were associated with significant side effects with the highest dosages of acyclovir but these promptly resolved when the agent was stopped. Acyclovir's apparently partial and transient action suggests that it will not have a role in the treatment of chronic hepatitis B virus infection.

Fifty patients with chronic HBs antigenemia and Dane particle-associated DNA polymerase and HBeAg in their serum were contrasted to 46 HBsAg positive patients who had neither serum DNA polymerase or HBeAg. The time from acute onset and the duration of antigenemia were longer in patients who were DNA polymerase and HBeAg negative than in those who had both serum markers. Cirrhosis, hypoalbuminemia, and sequelae of chronic liver disease were more common in DNA polymerase, HBeAg negative patients than in those who were positive. These findings are consistent with the hypothesis that active viral replication is an early, albeit prolonged stage in the development of advanced HBsAg-associated liver disease.

Eight patients with chronic hepatitis B infection (seven with chronic active hepatitis and one with chronic persistent hepatitis) were treated with daily intramuscular injections of human leucocyte interferon for periods of 5 to 8 weeks and in one case for 5 months. In one patient there was a marked fall in virus-associated DNA polymerase activity and in the number of DNA containing viral particles during each of two courses of interferon. Hepatitis Be antigen (HBeAg) also disappeared, the aspartate transaminase levels fell and liver histology improved. In the four other patients with detectable DNA polymerase activity there was an early fall but this was transient and in one of these patients there was a continuing rise in activity despite treatment. One other patient became HBeAg negative but hepatitis B surface antigen (HBsAg) titres were mostly unaffected by treatment. A marked decrease in T-lymphocyte mediated cytotoxicity towards HBsAg coated target cells was demonstrated and raises the possibility that an immunosuppressant action of interferon may offsets its direct anti-viral action but may also account for the improvement in liver function which occurred in some patients.

Ten young adult patients with chronic hepatitis B virus infection and positive hepatitis B e antigen and DNA polymerase (DNAP) levels were treated with alternating courses of seven to 28 days of 5 to 7.5 mg/kg of vidarabine monophosphate (adenine arabinoside monophosphate) and 28 days of human leukocyte interferon (IFN-alpha); three different regimens were given on an outpatient basis. All patients with a fall in their DNAP level, and the DNAP remained undetectable six months after treatment was stopped in one patient. The major side effect, which most often occurred in those patients receiving 7.5 mg/kg of vidarabine monophosphate, was severe muscular pains. This study demonstrated the feasibility of administering vidarabine monophosphate and interferon to outpatients. Based on data from this and other studies, it is now possible to use a relatively nontoxic regimen that includes 28 days of 5 mg/kg of vidarabine monophosphate in a larger controlled study to answer the question of efficacy.

Circulating complete and defective hepatitis B virus forms, as represented by full, DNA polymerase-positive and empty, DNA polymerase-negative Dane particles, respectively, were investigated in sera from patients with chronic hepatitis B virus infection and related to the presence of e antigen and antibody and to the histological findings on liver biopsy. Complete hepatitis B virus particles were detected in the serum of all patients postive for e antigen, their percentage ranging from 15 to 61% of the total Dane particle population. Although most of these cases had chronic persistent or chronic active hepatitis, complete viral particles were also found in serum of 3 healthy carriers of hepatitis B surface antigen who had e antigen. These results indicate that e antigen is a marker of active virus replication and support its association with infectivity. It is also associated with liver damage because production of complete virus is a feature of chronic hepatitis. In the presence of anti-e, detection of Dane particles in serum appeared to be related to the histological findings. Most of the healthy carriers had no Dane particles in serum, whereas 80% of the cases with chronic liver disease had circulating Dane particles. However, in contrast to the cases with e antigen, 98 to 100% of Dane particles in these cases appeared to be defective in nucleic acid material on electron microscopy after positive staining. All of the patients with chronic active hepatitis in this group had progressed to cirrhosis and it is possible that production of complete virus particles is reduced in the later stages of the illness.

Twenty patients with chronic active hepatitis and 12 patients with chronic persistent hepatitis associated with hepatitis B virus (HBV) infection were treated with human leukocyte interferon or adenine arabinoside alone or in combination. With interferon alone, four of 16 patients showed a permanent disappearance of HBV-associated DNA polymerase (DNAP) activity from serum. Of six patients treated with adenine arabinoside alone, only one patient became permanently DNAP-negative. With a regimen of multiple cycles of combined interferon and adenine arabinoside, seven of 16 male patients became permanently DNAP-negative. Of 69 patients who met the criteria for admission to the program, spontaneous decreases in DNAP activity without treatment were observed in only 9% during a mean observation period of 10 months. In general, patients with chronic active hepatitis, those who are female, and those with a history of recent steroid therapy responded to the antiviral agents significantly better than did the other patients.

Fourteen chimpanzees were inoculated with pre- and posttreatment sera from seven patients with persistent hepatitis B virus infection and chronic hepatitis who had permanent responses of their infection to treatment with interferon and/or adenine arabinoside. Inoculation of pretreatment serum at a dilution of 10(-8) from a patient with a Type I response to treatment [disappearance of Dane particle DNA polymerase (DNAP) activity, HBeAg, and HBsAg from serum] resulted in infection, while undiluted posttreatment serum (all markers negative) failed to infect another animal. Pretreatment sera (DNAP, HBeAg, and HBsAg positive) from all six patients with a Type II response to treatment (disappearance of DNAP activity and HBeAg but not HBsAg from serum) led to infection in six chimpanzees after inoculation of serum dilutions varying between 10(-2) and 10(-7). Inoculation of undiluted posttreatment sera (HBsAg positive and DNAP and HBeAg negative) from the same six patients produced no evidence of hepatitis B virus infection in another six animals. These results indicate that a Type I or II response to treatment with these antiviral agents reduces the infectivity in the serum of patients with chronic hepatitis B to below the level of detection by this assay. Such changes should be useful in interrupting spread of the infection between individuals. Our findings suggest that the serum of some patients who, without treatment are HBsAg positive and DNAP and HBeAg negative, may also be free of detectable infectious hepatitis B virus.

Experiments were done on rats to investigate the nature of the renal response to metabolic acidosis and the changes in enzyme activity associated with increased ammoniagenesis. When metabolic acidosis was induced with oral feeding of ammonium chloride for 48 hr, there was an increase of activity of the enzyme phosphoenolpyruvate carboxykinase (PEPCK) in whole kidneys as well as in the kidney cortex. There was no change in PEPCK in liver, and glucose-6-phosphatase showed no change in kidney or liver in response to metabolic acidosis. The increase in PEPCK activity in kidney cortex varied with the degree of acidosis and there was a close correlation between cortical PEPCK activity and urinary ammonia. Kidney cortex mitochondrial PEPCK did not change in response to metabolic acidosis. An increase in PEPCK occurred as early as 6 hr after NH(4)Cl feeding, before there was any increase in kidney glutaminase I activity. Rats fed sodium phosphate, or given triamcinolone intramuscularly, developed a metabolic alkalosis, but there was increased urinary ammonia and an increase in activity of renal cortical PEPCK. Triamcinolone plus ammonium chloride induced a greater increase of PEPCK activity than triamcinolone by itself; on the contrary, the rise of glucose-6-phosphatase induced by triamcinolone was not enhanced by acidosis. Glucose-6-phosphatase from control and acidotic rats had identical kinetic characteristics. The results indicate that increased PEPCK activity is constantly related to increases of urinary ammonia. It is proposed that the increase of PEPCK activity is the key event in the ammoniagenesis and gluconeogenesis which follow on metabolic acidosis.