Multiple skeletal muscle mitochondrial DNA deletions in patients with unilateral peripheral arterial disease

Peripheral arterial disease (PAD) is associated with metabolic derangements and accumulation of the common 4977 bp mitochondrial DNA (mtDNA) deletion mutation. The current study was undertaken to test the hypothesis that PAD is associated with multiple mtDNA deletions. Gastrocnemius biopsies were obtained from nine patients with unilateral PAD. DNA extracted from the biopsies was analyzed for mtDNA deletions using a primer-shift PCR strategy. Multiple primers and strict, prospective criteria were used to identify deletions. PAD was associated with multiple mtDNA deletions (average of 8.2 distinct deletions in muscle from the hemodynamically affected limb). mtDNA injury was present in both the worse- and less-affected limbs of the unilateral PAD patients, and the estimated degree of mtDNA injury was strongly correlated in the two limbs on an intra-subject basis. The 4977 bp deletion was frequently identified, but was not always the deletion of highest frequency in individual samples. The estimated relative frequency of the 4977 bp deletion was correlated with the overall mtDNA injury in the biopsies. In summary, PAD is associated with mtDNA injury as reflected by multiple deletion mutations. As the mutations are not limited to the ischemic limb in unilateral patients, they are unlikely to contribute to the pathophysiology of claudication.     

Haemodynamic changes in non-alcoholic (viral) liver cirrhosis studied by computed tomography (CT) arterial portography and CT arteriography

AIMS: To evaluate haemodynamic and vascular changes in non-alcoholic (viral) cirrhosis on conventional computed tomography (CT), CT arteriography (CTA) and CT arterial portography (CTAP), and to determine the cause of the observed reticular stain on angiography. METHODS: Using surgically resected liver specimens from 31 patients with viral hepatitis associated hepatocellular carcinoma, images of conventional CT, CTA, CTAP and the sinusoidal phase of hepatic arteriography were retrospectively analysed and compared with pathology of the non-cancerous portion of the liver. RESULTS: Computed tomography arteriography showed inhomogeneous enhancement (diffuse, low-density nodules) in a total of 16 samples (52%); in eight of 10 (80%) cirrhotic livers, three of six (50%) precirrhotic livers, five of 12 (42%) livers with chronic active hepatitis and none of three with no active liver disease. The frequency of inhomogeneous enhancement became significantly higher with increasing severity of parenchymal damage (P < 0.05). In contrast, conventional CT and CTAP showed homogeneous enhancement in all 31 (100%) patients. There was no correlation between inhomogeneous enhancement on CTA and reticular staining on sinusoidal-phase hepatic angiograms. Inhomogeneous enhancement was frequently seen in patients with hepatitis B surface antigen and/or anti-hepatitis C virus antibody compared with those without them (P < 0.05). CONCLUSION: The CTA was much more sensitive in detecting haemodynamic changes in the cirrhotic liver than CTAP, conventional CT and sinusoidal-phased hepatic angiography. Further study is required to clarify the mechanism of inhomogeneous enhancement on CTA and homogeneous enhancement on CTAP seen in cirrhosis.     

Atrial fibrillation is associated with accumulation of aging-related common type mitochondrial DNA deletion mutation in human atrial tissue

STUDY OBJECTIVE: Accumulation of somatic mutations of mitochondrial DNA (mtDNA) contributes to the aging process and progressive organ dysfunction. We investigated the mitochondrial DNA with 4977-base-pair mtDNA deletion mutation (mtDNA(4977)) in human atrial tissue and correlated the amount of mtDNA(4977) to clinical atrial fibrillation (AF). METHODS AND RESULTS: Atrial tissue from the right atrial appendage was obtained in 88 patients during open-heart surgery (22 children/adolescents and 66 adults). The amount of mtDNA(4977) was measured using a nested polymerase chain reaction protocol and normalized to wild-type mtDNA. We found that the mtDNA(4977) was absent in all 22 pediatric/adolescent patients. In the adult group, the relative amount of mtDNA(4977) was significantly higher in patients with AF than in patients without AF (0.55 +/- 0.26 vs 0.35 +/- 0.29, p < 0.007) [mean +/- SD]. The amount of mtDNA(4977) was also positively associated with age (r = 0.29, p < 0.01). Left and right atrial pressures, left atrial dimension, hypertension, and cardiac diagnosis did not influence the amount of mtDNA(4977) significantly. Further multivariate analysis showed that both aging and AF contributed independently to the accumulation of mtDNA(4977). CONCLUSION: AF is associated with an increase of mtDNA(4977). This change is similar to the aging process of atrial tissue and might contribute to atrial dysfunction in AF.     

Interferon reduces somatic mutation of mitochondrial DNA in liver tissues from chronic viral hepatitis patients

SUMMARY: We recently reported that the genetic instability resulting in the high rate of mitochondrial DNA (mtDNA) mutation in noncancerous liver tissue is consistent with the multicentric hepatocarcinogenesis detected clinically. Interferon (IFN) has been reported to reduce hepatocarcinogenesis in individuals with hepatitis virus infection. Liver biopsy specimens were obtained from 26 patients with chronic hepatitis C virus (HCV) infection before and after IFN therapy (total dose: 252 million units). The mean (+/-SD) age of the study population was 45 +/- 9 years and 13 (50%) were male [mode of acquisition: blood transfusion (27%), unknown (73%); viral load: 5.2 +/- 1.1 k copies/mL; duration of infection: 17 +/- 9 years (65%), unknown (35%); genotype: I (4%), II (80%), III (8%), IV (8%); alcohol intake: positive (31%), negative (69%)]. DNA samples were extracted from the specimens and subjected to direct sequencing. The mtDNA mutation frequency in the D-loop was increased in liver specimens from individuals with HCV infection compared with 21 controls (2.5 vs 0.6, P < 0.001). IFN therapy decreased the mtDNA mutation (mean difference = 0.7, P < 0.001) and the decreased number of mtDNA mutations was positively correlated with suppression of the total histological activity index score (mean difference = 1.3, P < 0.01). These results clearly indicate that the mutational rate of mtDNA is strongly associated with IFN therapy. Thus, analysis of mtDNA could provide a new criterion for the therapeutic evaluation of the effect of IFN, and may be useful for the prediction of risk of carcinogenesis.     

Relationship between iron concentration and hepatitis C virus RNA level in liver tissue

Patients with chronic hepatitis C virus (HCV) infection frequently have increased hepatic iron stores. The role of hepatitis C in hepatic iron deposition is unknown. The authors examined whether there is a relation between hepatitis C virus level in liver tissue and hepatic iron concentration. Forty-two paired samples obtained from the liver explants of five patients who underwent transplantation for liver disease due to hepatitis C were studied. Hepatitis C virus levels were measured at multiple sites within each liver by a branched deoxyribonucleic assay. Measurements of hepatic iron concentration were made at adjacent sites by a colorimetric assay. Random effects modeling showed wide intrahepatic variation in hepatic HCV ribonucleic acid (RNA) concentration (variance = 1.2 x 10(4) [mEq/g]2) and hepatic iron concentration (variance = 1.3 x 10(6) [microg/g]2). There was, however, a trend toward an association between the mean HCV level and the mean hepatic iron concentration for each liver (r = 0.30, p = 0.05). In conclusion, HCV level and iron concentration varied within and between cirrhotic livers. Variability in intrahepatic iron concentration was not related to variability in intrahepatic HCV RNA concentration. More studies are needed to determine the cause of variability in hepatic iron and HCV RNA concentration within and between livers in patients with chronic hepatitis C.     

Oxidative damage to mitochondrial DNA and its relationship to diabetic complications

Increased oxidative stress induced by hyperglycemia may contribute to the pathogenesis of diabetic complications. Oxidative stress is known to increase the conversion of deoxyguanosine (dG) to 8-hydroxydeoxyguanosine (8-OHdG) in DNA, which is linked to increased mitochondrial DNA (mtDNA) deletions. We investigated mtDNA deletions and 8-OHdG in the muscle DNA of non-insulin-dependent diabetes mellitus (NIDDM) patients. mtDNA deletion of 4977 bp (delta mtDNA4977) and the content of 8-OHdG in the muscle DNA of the NIDDM patients were much higher than those of the control subjects. There was a significant correlation between delta mtDNA4977 and the 8-OHdG content (P < 0.0001). Both delta mtDNA4977 and the 8-OHdG content were also correlated with the duration of diabetes. Delta mtDNA4977 and the 8-OHdG content in muscle DNA increased in proportion to the severity of diabetic nephropathy and retinopathy. This is the first report that an increase in delta mtDNA4977 and 8-OHdG is proportional to the severity of diabetic complications. Oxidative mtDNA damage is speculated to contribute to the pathogenesis of diabetic complications though a defect in mitochondrial oxidative phosphorylation or other mechanisms. 8-OHdG and delta mtDNA4977 are useful markers to evaluate oxidative mtDNA damage in the diabetic patients.     

Mitochondrial DNA deletions and the aging heart

Mitochondrial DNA (mtDNA) mutations appear to be associated with a wide spectrum of human disorders and proposed to be a potential contributor of aging. However, in an age-dependent increase of the common 4977 bp deletion of human mtDNA still many unanswered questions remain. Comparing mtDNA copy levels in different tissues revealed that cardiac muscle had the highest, while the cortex cerebelli showed the lowest copy number of mtDNA in every donor. Intriguingly, mtDNA copy number showed no changes during aging. In heart tissue, the amount of 4977 bp mtDNA deletion increased in an age-dependent manner showing significant differences at the age of 40 years and older (p<0.005). In vitro studies analyzing human normal cells transfected with telomerase (BJ-T) revealed that oxidative stress (OS)--a well accepted promoter of aging--induced 4977 bp deletion and point mutations as demonstrated by real-time PCR and DHPLC analysis. Interestingly, OS induced apoptosis only in transformed human fibroblasts by activation of the intrinsic (mitochondrial-mediated) signalling pathway as indicated by morphological damage of mitochondria, DNA laddering and increase of the Bax/Bcl-2 ratio. In conclusion, in heart tissue, the amount of the 4977 bp deletion increased in an age-dependent manner and it was more detectable after the 4th decade of life, although there was some scatter in the data. Since, apoptosis was induced by the mitochondria-mediated pathway only in transformed cells, the role for apoptosis in normal tissue of the aging heart remains unclear.     

Oxidative stress and its impact on mitochondrial DNA in pulmonary tuberculosis patients- a pilot study

BackgroundPulmonary tuberculosis (PTB) remains a major cause of morbidity and mortality all around the world. Recent studies have pointed out increased oxidative stress and also DNA damage in peripheral blood in PTB. Till date, to the best of our knowledge, no study has so far been conducted to show the mitochondrial DNA (mtDNA) deletions mapping in PTB patients. Therefore we performed the present study with the aim to investigate oxidative stress parameters along with mtDNA damage in newly diagnosed untreated PTB patients.Material and methodsThis is a prospective study carried out in Mahatma Gandhi Institute of Medical Sciences, Sevagram,Wardha, Maharashtra during september 2017 to september 2018.Thirty newly diagnosed untreated PTB patients and thirty age matched healthy controls were enrolled in the present study. Analysis of Oxidative stress parameters such as nitric oxide (NO) and malondialdehyde (MDA) were done by calorimetric methods. Assessment of mitochondrial DNA damage was carried out by mtDNA deletions mapping using primer shift long range polymerase chain reaction technique.ResultsThere was significant increase in levels of oxidative stress parameters, nitric oxide and malondialdehyde, in PTB patients compared to controls (p < 0.01). Generally there are two common deletion sites of “13 bp direct repeats” (ACCTCCCTCACCA) in mtDNA. One at the junction sites from bp 8470 to 8482 bp and another from bp 13447 to 13460 bp which make mtDNA more prone for 4977bp deletion. Out of thirty cases of PTB, two cases showed mtDNA damage in the form of mtDNA deletion of 4977bp. There was no mtDNA deletion in any control which can be attributed to continuous generation of oxidative stress.ConclusionThis pilot study has been able to demonstrate that compared to controls, in newly diagnosed pulmonary tuberculosis patients some mtDNA damage did occur and was probably due to continuous generation of oxidative stress in tuberculous patients. However, sample size is too small to draw any conclusions but definitely a more comprehensive study, by recruiting more number of pulmonary tuberculosis patients is warranted to establish correlation between oxidative stress and mtDNA damage in PTB.     

Occult hepatitis B virus in liver tissue of individuals without hepatic disease

BACKGROUND/AIMS: While many data are available concerning occult hepatitis B virus (HBV) infection in patients with hepatic disorders, there is little information about this cryptic infection in individuals without liver disease. The aim of this study was to investigate the prevalence of occult HBV in the general population by examining liver specimens from a large series of HBV-surface-antigen negative individuals with no clinical and biochemical evidence of liver disease. METHODS: The presence of HBV DNA was evaluated by testing, through polymerase chain reaction techniques, DNA extracts from 98 liver-disease-free individuals who underwent liver resection or needle biopsy during abdominal surgery. Sixteen of them were anti-HBV-core antigen (anti-HBc) positive and 82 were HBV serum-marker negative. All patients were negative for antibody to hepatitis C virus. RESULTS: Occult HBV infection was revealed in 16 of the 98 cases (16.3%). In particular, 10/16 anti-HBc positive (62.5%) versus 6/82 (7.3%) HBV-seronegative individuals were occult carriers (p<0.0001). CONCLUSIONS: This study revealed that about 1/6 of the Italian general population might be carriers of occult HBV infection, and this condition is significantly associated with the anti-HBc positive status.     

Assessment of fibrosis and cirrhosis in liver biopsies: an update

The liver biopsy specimen represents valuable material for the assessment of fibrosis and cirrhosis. Despite limitations related to sampling and interpretation, histologic examination remains the gold standard for staging chronic liver diseases. Hepatic fibrosis is currently viewed as a dynamic process that may often regress after successful treatment of chronic liver diseases. Even the excess fibrous tissue of cirrhotic livers may sometimes regress over time. Distinguishing between the amount of hepatic fibrosis and the disease stage is important for the assessment of the effects of antifibrotic treatments. Recent studies suggest that the proportion of the liver biopsy specimen occupied by collagen is correlated with the hepatic venous pressure gradient in liver transplant recipients with hepatitis C virus infection, with or without cirrhosis, and represents a predictor of clinical decompensation. This parameter has also been found to correlate with liver stiffness measurements of patients with chronic viral hepatitis obtained by transient elastography. Therefore, quantitative assessment of hepatic fibrosis in liver biopsy specimens holds promise as a prognostic marker, and as a means to validate noninvasive markers of fibrosis.     

心肌mtDNA4977缺失与扩张型心肌病猝死的关系

目的探讨扩张型心肌病(DCM)猝死者心肌线粒体DNA(mtDNA)4977缺失情况及其与猝死的关系.方法从近7年尸检案例中挑选11例DCM猝死和14例对照组病例及心肌组织蜡块,按常规方法提取心肌mtDNA,用PCR、琼脂糖紫外凝胶成像技术确定扩增产物激光密度,初步定量检测mtDNA4977缺失率.结果DCM猝死11例中,未成年人2例;成人9例,均为男性,年龄22～49(平均38)岁.对照组14例中,未成年人1例;成人13例,其中男11例,女2例,年龄19～47(平均37.23)岁,死因为机械性损伤和窒息各2例,电击死2例,中毒2例,非心肌病猝死6例.DCM11例(占100%)、对照组2例(占14.28%)检见不同程度的mtDNA4977缺失;两组病例mtDNA4977缺失率均值分别为0.92%和0.09%,差异有统计学意义.结论DCM猝死者心肌可检见mtDNA49 77缺失;其心肌mtDNA4977缺失突变与DCM猝死有关.     

Intrahepatic expression of pre-S1 and pre-S2 antigens in chronic hepatitis B virus infection in relation to hepatitis B virus replication and hepatitis delta virus superinfection.

Hepatocyte expression of pre-S1 and pre-S2 in relation to hepatitis B virus replication (hepatitis B virus-DNA in serum and HBcAg in the liver), histological activity and hepatitis delta virus superinfection was studied by indirect immunofluorescence on frozen sections of liver specimens from 68 patients with chronic hepatitis B virus infection. All 44 patients with chronic type B hepatitis had pre-S1 and pre-S2 display in the liver. The distribution of pre-S1 in the liver was membranous in one, mixed membranous and cytoplasmic in 12, and cytoplasmic in 31. The distribution of pre-S2 was membranous in one, mixed membranous and cytoplasmic in 26, and cytoplasmic in 17. Membranous expression of pre-S1 was significantly more prevalent in patients with active hepatitis B virus replication than in those without (13/28 v 0/16, p < 0.001), regardless of the histological activity, as was membranous expression of pre-S2 (27/28 v 0/16, p < 0.001). In contrast, a significantly higher extent of cytoplasmic expression of pre-S1 and pre-S2 was noted in patients without active hepatitis B virus replication than in those with. Of 24 patients with chronic type D hepatitis virus, eight had active hepatitis B virus replication, and the other 16 did not. The distribution and quantitative expression of pre-S1 and pre-S2 in the liver in these patients also correlated significantly with the status of hepatitis B virus replication and, moreover, showed little or no difference from those without hepatitis delta virus infection. In conclusion, all patients with chronic type B hepatitis had synthesis and display of pre-S1 and pre-S2 in the liver. The distribution and quantitative expression of pre-S1 and pre-S2, however, were closely related to the status of hepatitis B virus replication, but not to the histological activity. Hepatocyte expression of pre-S1 and pre-S2 in chronic type D hepatitis also correlated significantly with status of hepatitis B virus replication, and was not modulated by concurrent hepatitis delta virus infection.     

Simultaneous occurrence of malignant fibrous histiocytoma and hepatocellular carcinoma in cirrhotic liver: A case report

Primary hepatic malignant fibrous histiocytoma (MFH) is rarely encountered. There have been no reports to date of hepatic MFH associated with liver cirrhosis. The presence of liver cirrhosis is considered an adjunctive feature favoring sarcomatoid hepatocellular carcinoma (HCC) in the diagnosis of spindle cell tumors in liver. We describe here a 59-year-old man with liver cirrhosis due to hepatitis B virus infection 20 years ago. On abdominal computed tomography scanning, two distinct hepatic masses were identified in the background of cirrhosis, which had different radiological features from conventional HCC. He underwent segmentectomy for removal of the tumors. The pathological examination of surgically resected specimen revealed the large malignant spindle cell tumor and small conventional HCC. Additional tissue sampling and immunohistochemical stainings demonstrated that the spindle cell tumor was consistent with MFH. On the post-operative follow-up for 21 mo, a round mass showing similar radiological findings for the previous MFH was appeared on the surface of resection margin, suggesting the recurrence. Despite its rarity, hepatic MFH should be considered during differential diagnosis, even in cirrhotic patients, and extensive tissue sampling and immunohistochemical analyses are necessary in the diagnosis of hepatic spindle cell tumors.     

Lack of evidence for involvement of fetal microchimerism in pathogenesis of primary biliary cirrhosis

Microchimerism may be involved in the etiopathogenesis of autoimmune diseases such as scleroderma. Primary biliary cirrhosis (PBC) shares some features with scleroderma, including a female predominance and a histologic picture reminiscent of chronic graft-versus-host disease. Our aim was to detect Y-chromosome-specific sequences as a marker for microchimerism in liver tissue of female patients with PBC. Liver biopsies of 105 female patients were investigated (28 patients with primary biliary cirrhosis, 25 patients with chronic hepatitis C, 6 patients with chronic hepatitis B, 9 with autoimmune hepatitis, and 37 patients with other liver diseases) by a sensitive Y-chromosome-specific polymerase chain reaction and/or fluorescence in situ hybridization (FISH) technique for the detection of the Y chromosome on a single cell level. In the liver of 9 (8.6%) female patients Y-chromosome-specific sequences were detected by PCR. Five of the patients had PBC as underlying disease, 2 had chronic hepatitis C, and 2 other liver diseases. No significant difference in the positivity rate for Y-specific sequences in females with PBC and patients with other liver diseases was found (P > 0.05). By FISH, single cells with one Y chromosome were detected in liver specimens from 3 of 21 patients suffering from PBC and from 1 of 13 patients with other liver diseases. In summary, microchimerism can be detected in livers of patients with hepatic diseases. However, in our study we found no evidence for an increased prevalence of microchimerism in the livers of patients with primary biliary cirrhosis. Our data suggest that microchimerism does not play a significant role in the development of PBC.     

Chronic delta infection and liver biopsy changes in chronic active hepatitis B

The delta agent consists of particles of RNA nucleoprotein and is probably a defective virus present only in the livers of patients with B-viral acute or chronic liver disease. Its frequency is significantly greater in patients with chronic active hepatitis B than in those with persistent viral hepatitis B, suggesting that chronic delta infection may increase the severity of liver disease. We studied biopsy or autopsy tissue samples from 57 patients with chronic active hepatitis B for morphologic differences between chronic delta-positive and delta-negative cases. The delta-positive cases had significantly greater portal and parenchymal inflammatory change, parenchymal necrosis, and nuclear dysplastic and polyploid change than did the delta-negative cases. These findings suggest that chronic delta infection, with ongoing delta replication, may increase the degree of hepatic damage, and possibly hasten the progression of liver disease, in patients with chronic active hepatitis B.     

病毒性心肌炎患者心肌细胞线粒体DNA缺失的定量分析

为探讨病毒性心肌炎 (VMC)患者心肌细胞线粒体 DNA(mt NDA)缺失突变情况及意义 ,用定量 PCR法检测 2 0例 VMC患者心肌细胞及其外周血淋巴细胞 mt DNA4 977碱基对 (mt DNA4 977)和 mt DNA74 36 碱基对 (mt D-NA74 36 )缺失率。取 10例健康意外死亡者心肌和 2 0例献血员外周血淋巴细胞作正常对照。结果显示 ,正常对照者和 VMC患者心肌细胞均存在 m t DNA4 977及 mt DNA74 36缺失 ,合计缺失率分别为 0 .176 %、0 .384 % ,二者差异显著 ,P<0 .0 5 ;VMC患者外周淋巴细胞 mt DNA缺失程度与心肌细胞呈一致性改变 ,且有良好的相关性 (r=0 .92 0 ,P<0 .0 0 1)。提示 mt DNA缺失可能是 VMC发病过程中重要的心肌损伤机制 ;外周淋巴细胞在研究心肌细胞 mt DNA缺失中的作用值得进一步探讨     

Histopathological heterogeneity in fulminant hepatic failure

The clinicopathological features of 38 patients admitted consecutively for fulminant hepatic failure were studied. Histopathological material was reviewed in all patients. Both percutaneous and whole livers (either explanted or autopsy specimens) were available in 16 patients: whole livers only in 12 patients and biopsy specimens only in 10 patients. All patients were negative for antibodies to hepatitis C, whereas 24% had hepatitis B infection and 10% had adverse drug reactions. Livers from 75% of patients showed confluent hepatic necrosis. However, there was considerable variability in the extent of necrosis, and biopsy specimens from about 50% of the most severely affected livers showed only minimal bridging necrosis. In patients with massive hepatic necrosis, percutaneous liver biopsy specimens were frequently misleading because of regional inhomogeneities. Interestingly, five patients (13%) had established cirrhosis at the time of diagnosis. The best clinical predictors of survival were age and the maximal grade of encephalopathy. By contrast, neither the severity of confluent hepatic necrosis nor the etiology predicted the decision to transplant or the outcome. There were no differences in the histopathology corresponding to different etiologies. In summary, the approach to the patient with fulminant hepatic failure should be guided principally on clinical grounds, and further classification should be based on pathological and etiologic considerations. However, histological classification and prognosis based on percutaneous biopsy specimens alone may be misleading.     

Changes of hepatitis B virus DNA in liver and serum caused by recombinant leukocyte interferon treatment: analysis of intrahepatic replicative hepatitis B virus DNA

Twenty patients with HBeAg-positive chronic liver disease were given large doses of recombinant leukocyte interferon for 4 weeks. Changes of hepatitis B virus DNA in livers and sera were analyzed by the molecular hybridization technique in paired biopsies obtained before and 2 weeks after treatment. Serum hepatitis B virus DNA was examined before, during and after the treatment until 4 weeks post-interferon. Analysis of hepatic hepatitis B virus DNA revealed species that appeared to represent various forms of replicative hepatitis B virus DNA, i.e., relaxed circular, linear, supercoiled and single-stranded hepatitis B virus DNA, respectively. No evidence of integration of hepatitis B virus DNA in genomic DNA was obtained. Of 15 cases which were positive for hepatic hepatitis B virus DNA before treatment and in which paired biopsies were obtained, hepatic hepatitis B virus DNA became negative in 4, decreased in 5 and unchanged in 6. Among several types of replicative viral DNA in liver tissue, supercoiled hepatitis B virus DNA tended to remain after other forms were reduced. A close correlation between hepatic and serum hepatitis B virus DNA was found in 37 liver biopsy samples and corresponding sera. These results indicate that interferon treatment reduces serum hepatitis B virus levels by inhibiting viral replication in the liver and that persistence or reappearance of hepatitis B virus in serum after interferon is associated with replication.