TT virus infection in chronic liver disease.

BACKGROUND/AIMS: The exact role of the novel hepatotropic TT virus regarding the etiology of viral hepatitis, as well as the progression towards chronic liver disease has as yet not been defined. Moreover, the contribution of TTV infection to the course of chronic hepatitis B or C virus infections also still awaits clarification. Hence, the aim of our study was to investigate the impact of TTV infection on clinical severity and histology of chronic liver disease originating from HBV and/or HCV infections in Thai patients concomitant with the determination of TTV's association with non-B, non-C chronic liver disease and compared to its prevalence among voluntary blood donors. METHODOLOGY: DNA was extracted from the sera collected from 115 hepatitis B patients, 41 hepatitis C, and 48 negative for either viral marker, who had all been diagnosed with chronic liver disease ranging from chronic hepatitis over cirrhosis to hepatocellular carcinoma. The sera obtained from 200 voluntary blood donors served as controls. TTV DNA was amplified by seminested polymerase chain reaction (PCR) employing primers derived from the genome's most conserved region. The PCR products were analyzed by gel electrophoresis. Liver function tests were performed by means of a chemical analyzer. RESULTS: TTV DNA was detected in 20% of the HBV-positive and 19.5% of the HCV-positive chronic liver disease patients. Within the group of patients seronegative for both viral markers, TTV was detected in 8.3%. Furthermore, its DNA was identified in 6.8% of the HCC patients and finally, in 7% of the blood donors. Yet, no significant differences between TTV infected and non-infected patients were found as to demographic data, assumed source of infection, biochemical abnormalities, or severity of liver histology. CONCLUSIONS: TTV appears to be highly prevalent on a worldwide scale but regarding etiology of and progression towards serious liver disease, its contribution seems to be minor if not altogether non-existent. Hence, regarding clarification of its clinical significance, further studies are certainly required.     

A prospective study on TT virus infection in transfusion-dependent patients with beta-thalassemia

A novel DNA virus designated TT virus (TTV) has been reported to be involved in the development of posttransfusion non-A-C hepatitis. We evaluated the frequency and natural course of TTV infection in a cohort of transfusion-dependent thalassemic patients in a 3-year follow-up study. Ninety-three serum hepatitis C virus (HCV) antibody-negative patients (median age of 8 years; range, 0 to 25) from eight centers were studied. Of them, 34 (37%) had an abnormal alanine-aminotransferase (ALT) baseline pattern, and the other 12 (13%) showed ALT flare-ups during the follow-up. TTV DNA in patient sera collected at the time of enrollment and at the end of follow-up was determined by polymerase chain reaction (PCR). In parallel, serum samples from 100 healthy blood donors were also tested. At baseline, 87 patient sera (93.5%) tested positive for the TTV DNA. Of these TTV DNA-positive patients, 84 (96.5%) remained viremic at the end of the study period. Of the 6 TTV DNA-negative patients, 3 acquired TTV infection during follow-up. However, no definite relation was observed between the results of TTV DNA determination and ALT patterns. TTV viremia was also detectable in 22% of blood donors. In conclusion, TTV infection is frequent and persistent among Italian transfusion-dependent patients. The high rate of viremia observed in healthy donors indicates that the parenteral route is not the only mode of TTV spread.     

A prospective study of transfusion-transmitted virus transmission by blood transfusion

Recently, a new single-stranded DNA virus (TT virus, TTV) has been isolated and related to post-transfusion hepatitis. The aim of this study was to investigate the prevalence of TTV in blood donors and blood recipients, and the incidence of TTV transmission by blood transfusion. TTV DNA and serum markers of hepatitis B virus (HBV) and hepatitis C virus (HCV), were examined in 130 blood recipients, and the presence of TTV was studied in their 340 corresponding blood donors. The prevalence of TTV infection was 10.6% (36/340) in donors and 8.5% (11/130) in blood recipients, before transfusion. Eighteen subjects (15.1%) were found to be TTV positive, after transfusion, in the 119 blood recipients without TTV before transfusion; at least one of the corresponding donors was TTV positive. There were 46 subjects with post-transfusion hepatitis virus infection, 45 with HCV infection (including seven co-infected with TTV) and two with HBV infection (including one co-infected with HCV and one co-infected with TTV). The recipient with TTV and HBV co-infection and three of the seven patients with TTV and HCV infection had alanine aminotransferase (ALT) levels higher than 90Ul^–1, but only two of the 10 isolated TTV infections had a mild ALT elevation. These results show that prevalence of TTV was high in blood donors and hospitalized patients, and isolated TTV infection is not related to significant ALT elevation.     

TT viral infection through blood transfusion: retrospective investigation on patients in a prospective study of post-transfusion hepatitis

AIM To investigate the role of blood transfusion in TT viral infection (TTV).METHODS We retrospectively studied serum samples from 192 transfusion recipients who underwent cardiovascular surgery and blood transfusion between July 1991 and June 1992. All patients had a follow-up every other week for at least 6 months after transfusion. Eighty recipients recipents blood before screening donors for hepatitis C antibody (anti-HCV), and 112 recipients reveiver screened blood.Recipients with alanine aminotransferase level ＞ 2.5 times the upper normal limit were tested for serological markers for viral hepatitis A, B,C, G, Epstein-Barr virus and cytomegalovirus.TTV infection was defined by the positivity for serum TTV DNA using the polymerase chain reaction method. RESULTS Eleven and three patients, who reveiver anti-HCV unscreened and screened blood, respectively, had serum ALT levels ＞90 IU/L. Five patients (HCV and TTV: 1; HCV,HGV, and TTV: 1; TTV: 2; and CMV and TTV: 1 )were positive for TTV DNA, and four of them had sero-conversion of TTV DNA. CONCLUSION TTV can be transmitted via blood transfusion. Two recipients infected by TTV alone may be associated with the hepatitis.However, whether TTV was the causal agent remains unsettled, and further studies are necessary to define the role of TTV infection in chronic hepatitis.     

上海地区血液透析患者与供血者中输血传播病毒DNA检测及部分核苷酸序列分析

目的　了解上海地区暴露于血及血制品的血透患者中输血传播病毒（ＴＴＶ）感染率。方法　采用套式ＰＣＲ技术,检测了 ６例血透患者和 ４９例供血员血清中 ＴＴＶ ＤＮＡ,并对其中各 １例 ＰＣＲ产物（２７２ｂｐ）测］３。结果血透患者ＴＴＶ ＤＮＡ的检出率为 ３２．８％（２０／６１）,供血员的检出率为 ２４． ５％（１２／４９）。 ２０例 ＴＴＶＤＮＡ阳性血透患者中,６例为单纯ＴＴＶ感染,６例为ＴＴＶ、ＨＣＶ及ＨＧＶ重叠感染,４例为ＴＴＶ、ＨＣＶ和４例为ＴＴＶ、ＨＧＶ重叠感染。在所有ＴＴＶ感染者中,仅发现１例血清ＡＬＴ升高,该病例为ＴＴＶ、ＨＣＶ及ＨＧＶ重叠感染。对ＰＣＲ阳性扩增产物２７２ｂｐ测序结果显示,上海株（ＳＨＰ、ＳＨＤ）核苷酸的同源性为９９．６％,与深圳株、２株日本株核着酸的同源性分别为９７．４％、９８．７％和９８．７％,表明ＴＴＶ上海株与深圳株及日本株（Ｎ２２、Ｇ１ａ）属同一亚型,首次证实了上海地区的ＴＴＶ感染。结论ＴＴＶ感染可经血传播。其致病性较弱,对ＴＴＶ的研究尚属开始,ＴＴＶ的病原学、流行病学及临床意义等问题还有待进一步探索和阐明。     

输血传播性病毒的流行病学及临床研究

目的:观察分析不同人群中TTV(transfusion transmitted virus)感染状况及相关临床意义。方法:在TTVORF1设计引物,建立巢式聚合酶链反应,检测不同人群中血清TTV DNA,并对比观察肝炎病人的临床表现。结果:29例健康人群,27例职业献血员,56例乙型肝炎,31例丙型肝炎和47例非甲～非庚型肝炎患者中,TTV DNA阳性率分别为6.9％、3.7％、23.2％、25.8％和42.6％。3种肝炎病人中,TTV DNA阳性和阴性组间4项主要临床指标无显著差异。结论:健康人群和职业献血员存在TTV健康携带者。非甲～非庚型肝炎患者TTV感染率最高。乙型和丙型肝炎患者重叠TTV感染较常见。3种肝炎病人中,合并TTV感染组与非感染组临床表现无明显差异。TTV的致病性尚待深入研究。     

Transfusion-transmissible virus and hepatocellular carcinoma: a case-control study

Although transfusion-transmissible virus (TTV) is often present in the serum of patients with acute and chronic non-A–C liver diseases, its hepatotropism, pathogenicity to the liver and hepatocarcinogenicity have not been proven. We used a case-control format to compare the prevalence of TTV infection among 148 southern African Blacks with hepatocellular carcinoma and 148 matched hospital-based controls, and to test for possible interactive effects between this virus and hepatitis B virus (HBV) and hepatitis C virus (HCV) in the development of the tumour. We also determined the prevalence of TTV in 988 blood donors in Gauteng province of South Africa. The presence of TTV DNA in serum samples was detected by using the polymerase chain reaction, Southern hybridization and nucleotide sequencing. Individuals infected with TTV did not have an increased risk of developing hepatocellular carcinoma (relative risk 1.1; 95% confidence limits 0.5–2.4). Moreover, co-infection with TTV did not further increase the risk of tumour development in patients chronically infected with HBV and/or HCV. TTV was present in the serum of 2.2% of blood donors: 4.0% in Black and 1.5% in White donors. We conclude that TTV is unrelated to the development of hepatocellular carcinoma in Black Africans.     

丙型及非甲-庚型肝炎患者血清TTV检测及临床分析

目的 了解郑州地区不同肝病患者中ＴＴＶ（ｔｒａｎｓｆｕｓｉｏｎ ｔｒａｎｓｍｉｔｔｅｄ ｖｉｒｕｓ）感染状况及其临床特点。方法 自行设计ＴＴＶ ＯＲＦ１保守区的两对引物,对２０例非甲－庚型肝炎和９７例丙型肝炎患者血清进行ＰＣＲ检测,并对３０例资料完整的丙肝患者是否合并ＴＴＶ感染及其临床特点进行分析。结果 丙型和非甲－庚型肝炎患者血清ＴＴＶ ＤＮＡ检出率分别为１６．５％（１６／９７）和２０％（４／２     

武汉地区职业献血员血清TTV等病毒核酸的检测

目的 调查武汉地区既往职业献血员血清TTVV DNA及其他几种肝炎病毒基因的状况与特点。方法采用PCR或巢式PCR对74例既往乡村献血员进行血清TTV DNA及HCV RNA、HGV RNA的检测。结果 TTVDNA、HCV RNA及HGV RNA阳性检出率分别为43.2％、23.0％与2.7％,TTV DNA检出显著高于其他肝炎相关病毒,HCV RNA阳性率显著高于HGV RNA阳性率。结论 既往长期的献血已造成地区乡村职业献血员TTV与HCV感染率的显著升高。     

Natural history of the TT virus infection through follow-up of TTV DNA-positive multiple-transfused patients

Little is known about the natural history and the pathogenicity of the TT virus (TTV). We present our findings of a cross-sectional study based on the TTV DNA screening of 173 multiple-transfused patients and a longitudinal study based on the follow-up of TTV DNA-positive patients. Overall, 48 patients (27.7%) tested positive for TTV DNA. The influence of the number of blood donor exposures on the prevalence of blood-borne viral infection indicates that TTV, hepatitis C virus (HCV), and an RNA virus known as GB virus C/hepatitis G virus (GBV-C/HGV) share a parenteral transmission, but that TTV, in contrast to the 2 other viruses, is also transmitted by at least another efficient means. The patients having a well-defined date of TTV infection were positive for TTV DNA during a mean period of 3.1 years. A chronic infection was observed in 31 cases (86%). TTV carriage appeared clinically benign in all patients. No clinical evidence of a disease potentially linked to the TTV infection was observed in patients with TTV DNA carriage over several years. The majority of TTV carriers had no biochemical evidence of liver disease. The prevalence of elevated serum alanine aminotransferase (ALT) level was higher in the TTV DNA-positive group, even in the absence of HCV infection, but the observed peaks of ALT level were most often transient and very mild. The prevalence of TTV DNA observed in blood recipients is consistent with that of TTV infection observed in blood donors. TTV infection frequently tends to persist. (Blood. 2000;95:347-351)     

TT virus infection in adult beta-thalassemia major patients

BACKGROUND AND OBJECTIVES: Patients with thalassemia-major are at risk of blood-borne viral infections. TT virus (TTV), a single stranded, circular DNA virus, has recently been found to be associated with acute and chronic hepatitis. The aims of this study were to assess the prevalence of TTV infection in adult patients with transfusion-dependent thalassemia, and to evaluate the clinical significance of TTV. DESIGN AND METHODS: We studied 68 adult patients with thalassemia major, 97% of whom were hepatitis C virus (HCV) antibody positive. TTV DNA was amplified from serum by heminested polymerase chain reaction (PCR). Direct sequencing of PCR products was used to establish TTV genotypes. RESULTS: TTV DNA was detected in 47 patients (69.1%). Sequence analysis of PCR products identified TTV genotype 1b as the most common viral genotype in this group. Patients co-infected by HCV and TTV had a significantly higher histologic grade score than patients with isolated HCV infection (5.1+/-2.7 vs. 2.8+/-1.7, p=0.02) while the stage score was not significantly different. INTERPRETATION AND CONCLUSIONS: TTV is highly prevalent among Italian multiply transfused patients. In these patients TTV viremia appears to affect the necro-inflammatory activity of hepatitis C, though no evidence of an effect on the evolution of fibrosis was found.     

Transfusion-transmitted virus in association with hepatitis A-E viral infections in various forms of liver diseases in India

AIM: To describe the prevalence of transfusion-transmitted virus (TTV) infection in association with hepatitis A-E viral infections in different forms of liver diseases in North India. METHODS: Sera from a total number of 137 patients, including 37 patients with acute viral hepatitis (AVH), 37 patients with chronic viral hepatitis (CVH), 31 patients with cirrhosis of liver and 32 patients with fulminant hepatic failure (FHF), were analyzed both for TTV-DNA and hepatitis A-E viral markers. Presence of hepatitis B virus (HBV), hepatitis C virus (HCV) and hepatitis E virus (HEV) infections was detected in different proportions in different groups. Moreover, TTV-DNA was simultaneously tested in 100 healthy blood donors also. RESULTS: None of the patients had hepatitis A virus (HAV) and hepatitis D virus (HDV) infections. Overall prevalence of TTV-DNA was detected in 27.1% cases with AVH, 18.9% cases with CVH, 48.4% cases with cirrhosis and 9.4% cases with FHF. TTV-DNA simultaneously tested in 100 healthy blood donors showed 27% positivity. On establishing a relation between TTV infection with other hepatitis viral infections, TTV demonstrated co-infection with HBV, HCV and HEV in these disease groups. Correlation of TTV with ALT level in sera did not demonstrate high ALT level in TTV-infected patients, suggesting that TTV does not cause severe liver damage. CONCLUSION: TTV infection is prevalent both in patients and healthy individuals in India. However, it does not have any significant correlation with other hepatitis viral infections, nor does it produce an evidence of severe liver damage in patients with liver diseases.     

Infection with TT virus, a novel transfusion-transmissible DNA virus, in haemophiliacs and in blood products

We evaluated the characteristics and rate of infection with TT virus (TTV), a novel DNA virus, in Japanese haemophiliacs. TTV DNA was measured in 60 haemophiliacs by semi-nested polymerase chain reaction. Co-infection with hepatitis C virus (HCV), hepatitis G virus (HGV) and human immunodeficiency virus (HIV) was also evaluated. In addition, the rate of detection of TTV DNA in blood products was evaluated. TTV DNA was detected in 35/60 haemophiliacs (58.3%). There were no differences in the backgrounds or characteristics between haemophiliacs with and without TTV infection, except for higher levels of IgG and IgM in patients with TTV infection. In patients infected with TTV of types other than type 1, which are rarely detected in Japan, the rate of co-infection with HCV of imported types was high; TTV of types other than type 1 in Japanese haemophiliacs were probably transmitted by imported blood products. TTV DNA was detected in over half of the blood products tested, but TTV DNA concentrations in these products were lower than in the serum of haemophiliacs.     

Prevalence of TT virus infection in blood donors with elevated ALT in the absence of known hepatitis markers

OBJECTIVE: Recently a novel DNA virus (TT virus) has been identified in Japan and shown to be associated with elevated aminotransferase levels after blood transfusion. The exact role of TTV in the pathogenesis of liver disease is yet to be established. Our aim was to determine the prevalence and role of TTV in the pathogenesis of elevated transaminases in healthy blood donors in the absence of markers for viral hepatitis A-C. METHODS: Stored sera were collected from 99 healthy blood donors with elevated alanine amino transferase (ALT) values that were discovered at the time of blood donation. A total of 146 samples were obtained from healthy donors with normal ALT values who were used as controls. None of the patients or controls had a history of blood transfusion or had clinical signs of acute or chronic hepatitis. Serological markers for hepatitis A, hepatitis B, and hepatitis C viruses were negative. TTV DNA was amplified and detected using polymerase chain reaction followed by gel electrophoresis. RESULTS: Five of 99 (5%) samples obtained from donors with elevated ALT had TTV DNA detected by PCR, as compared to one of 146 (0.7%) of those with normal ALT (p = 0.006). Among those with elevated ALT, mean ALT values in patients with TTV (296 +/- 305 U/L) were higher than in patients without TTV (95 +/- 37 U/L), but the difference was not statistically significant (p = 0.08). The two samples with highest ALT values (both >450 U/L) were among the five samples with detectable TTV DNA in serum. CONCLUSIONS: Although TTV is not likely to explain the majority of elevated ALT cases in otherwise healthy blood donors, TTV infection may potentially be associated with some cases. Based on these findings, we propose that the role of TTV in the pathogenesis of acute and chronic liver diseases merits further investigation.     

TTV与其它肝炎病混合感染及其基因型的研究

研究TTV与其它肝炎病混合感染对肝脏病变的影响及本地区TTVDNA的基因型。选TTV ORF1的保守序列作内外引物,采用微板核酸杂交－ELISA方法检测患者血清TTVDNA并对检测结果和临床资料进行统计学分析。选取异源性大于50％的序列作显色探针Ⅰ和显色探针Ⅱ,进行分型研究。学生、非甲－非戊型肝炎、慢性乙型肝炎和肝硬化患者血清TTV阳性率分别为3．3％、14．3％、12％、16％。TTV阳性和TTV阴性的慢性乙型肝炎及肝硬化患者,在年龄、性别、ALT和TBil之间无显著差异（P＞0．05）。本地区流行的TTV可分为两个主要的基因型,即I型（66．75）、Ⅱ型（25％）,部分存在混合感染（8．3％）。TTV可能与HBV、HCV有类似的传播途径,故常重叠感染。TTV与乙型肝炎及肝硬化混合感染后不影响两者的肝脏病变。TTV不是本地区非甲－非戊型肝炎的主要病因。     

Response of TT virus to IFN plus ribavirin treatment in patients with chronic hepatitis C

AIM: TT virus (TTV) is a newly described DNA virus related to postransfusion hepatitis that produces persistent viremia in the absence of clinical manifestations. PEG-IFN plus ribavirin have been useful in the treatment of chronic hepatitis C infection. This study investigated the responses ofTT virus(TTV) and hepatitis C virus (HCV) to PEG-IFN plus ribavirin therapy. METHODS: Fifteen patients infected with HCV were treated with PEG-IFN(0.5 μg/body weight/week) and ribavirin(1 000 mg-1 200 mg/daily) for 48 weeks. Blood samples were drawn at the beginning and the end of the therapy. Serum TTV DNA and HCV RNA were quantified by real time PCR. RESULTS: At the beginning of treatment, TIV infection was detected in 10/15 (66.6%) of HCV-infected patients. Loss of serum Trv DNA at the end of therapy occurred in 6/10(60%) patients. Out of these 6 patients, 4 (67%) became positive for TTV DNA after 6 months of therapy. Regarding HCV viremia, 11/15 (73%) patients were negative for serum HCV RNA after 48 weeks of therapy, 7/11 (64%) of these cases also became negative for TTV DNA following the combined treatment. In the 3/4 (75%) patients who were positive for HCV RNA at the end of therapy, TTV DNA was detected as well. Sustained HCV response at 6 months after treatment was 53% (8/15). CONCLUSION: No TTV sustained response can be achieved in any patient after PEG-IFN plus ribavirin administration.     

Transmission of and liver injury by TT virus in patients on maintenance hemodialysis

To study the prevalence and clinical significance of TT virus (TTV) infection in hemodialysis patients, we tested for TTV DNA in serum, using the nested polymerase chain reaction. The prevalence of TTV DNA in 352 hemodialysis patients was 32%, significantly higher than that in 50 healthy blood donors (12%). The prevalence increased with age (P = 0.0098); it was 20% (22/110) in patients aged less than 49 years, 37% (69/188) in those aged 50–69 years, and 41% (22/54) in those aged over 70 years. Other clinical features and the prevalence of other hepatitis viral markers tested did not differ between patients with TTV DNA and those without it. The detection rate of hepatitis C virus (HCV) and hepatitis G virus (HGV) viremias increased with duration of hemodialysis and with the number of blood transfusion units, but the prevalence of TTV viremia did not. Twenty-nine of 91 patients followed for 5 years were initially positive for TTV DNA. Of these 29 patients, 17 (59%) carried this viremia for at least 5 years. Fourteen of the 62 patients (23%) who were initially negative for TTV DNA acquired TTV viremia. Serum alanine aminotransferase (ALT) levels were elevated in patients with HCV viremia but not in patients with HGV or TTV viremia. However, the mean ALT level in patients with all three viremias (HCV, HGV, and TTV) was significantly higher than that in patients with one or two of the viremias. More than 30% of the hemodialysis patients had TTV viremia and the carrier state was maintained for years. The hemodialysis procedures, including blood transfusion, did not seem to be crucial for the transmission of TTV. The pathogenic effects of TTV on hepatitis appear to be limited. (Received July 21, 1998; accepted Sept. 25, 1998)     

TT virus infection in Thailand: prevalence in blood donors and patients with aplastic anemia

Aplastic anemia has been reported to occur after viral hepatitis of unknown etiology. Recently, TT virus (TTV), a novel DNA virus, was identified in a Japanese patient with posttransfusion non-A-E hepatitis. The prevalence of TTV infection was investigated among blood donors and patients with aplastic anemia in Thailand. Of 99 blood samples from blood donors, 37 tested positive for TTV DNA via semi-nested polymerase chain reaction (PCR) using TTV-specific primers. Seventeen percent of samples from blood donors younger than 20 were positive for TTV DNA, whereas 48% from donors older than 20 were positive. The high prevalence of TTV infection in Thailand is comparable to that reported in China (28%), Mongolia (43%), and Egypt (29%). Forty-two percent of newly diagnosed aplastic anemia patients tested also had TTV DNA in blood. The detection rate of TTV DNA in aplastic anemia patients does not differ significantly from rates in normal blood donors. Our present data thus argue against the role of this novel hepatitis-associated virus in the pathogenesis of aplastic anemia in Thailand. However, larger epidemiological studies may be needed to further evaluate their association.     

TT virus and hepatitis G virus infections in Korean blood donors and patients with chronic liver disease

AIM: To determine the prevalences of TTV and HGV infections among blood donors and patients with chronic liver disease in Korea, to investigate the association of TTV and HGV infections with blood transfusion, and to assess the correlation between TTV and HGV viremia and hepatic damage. METHODS: A total of 391 serum samples were examined in this study. Samples were obtained from healthy blood donors (n=110), hepatitis B surface antigen (HBsAg)-positive donors (n=112), anti-hepatitis C virus (anti-HCV)-positive donors (n=69), patients with type B chronic liver disease (n=81), and patients with type C chronic liver disease (n=19). TTV DNA was detected using the hemi-nested PCR. HGV RNA was tested using RT-PCR. A history of blood transfusion and serum levels of alanine aminotransferase (ALT) and aspartate aminotransferase (AST) were also determined. RESULTS: TTV DNA was detected in 8.2 % of healthy blood donors, 16.1 % of HBsAg-positive donors, 20.3 % of anti-HCV-positive donors, 21.0 % of patients with type B chronic liver disease, and 21.1 % of patients with type C chronic liver disease. HGV RNA was detected in 1.8 % of healthy blood donors, 1.8 % of HBsAg-positive donors, 17.4 % of anti-HCV-positive donors, 13.6 % of patients with type B chronic liver disease, and 10.5 % of patients with type C chronic liver disease. The prevalence of TTV and HGV infections in HBV- or HCV-positive donors and patients was significantly higher than in healthy blood donors (P<0.05), except for the detection rate of HGV in HBsAg-positive donors which was the same as for healthy donors. There was a history of transfusion in 66.7 % of TTV DNA-positive patients and 76.9 % of HGV RNA-positive patients (P<0.05). No significant increase in serum ALT and AST was detected in the TTV- or HGV-positive donors and patients. CONCLUSION: TTV and HGV infections are more frequently found in donors and patients infected with HBV or HCV than in healthy blood donors. However, there is no significant association between TTV or HGV infections and liver injury.     

Effect of TT virus co‐infection on interferon response in chronic hepatitis C patients

Abstract: Aim: TT virus (TTV) is a single stranded DNA virus found in serum of patients with post‐transfusion non‐A to ‐G hepatitis. TTV‐DNA has been investigated in sera of patients with various liver diseases. This study aimed at finding whether co‐infection with TTV in HCV patients, may influence the effect of interferon (IFN) in complete elimination of HCV, and analysed the correlation between HCV and TTV by semi‐quantification of both HCV RNAs and TTV DNA. Methods: In 28 chronic hepatitis C (CH‐C) patients with TTV co‐infection, the presence of TTV DNA was checked in sera six months before and after the end of IFN therapy. Result: Five out of 28 patients became negative for both HCV‐RNA and TTV‐DNA following IFN therapy. But 10 out of 28 patients persistently remained positive for both. Among the remaining 13 patients, 5 tested negative for HCV‐RNA but positive for TTV‐DNA. Post IFN therapy changes in serum alanine aminotransferase (ALT) levels did not appear to be influenced by the presence of TTV co‐infection. HCV‐RNA was found to be the most important predictor of IFN response in CH‐C patients with TTV co‐infection. TTV DNA level in sera had no correlation with IFN response. In addition, there was no relationship between HCV RNA and TTV DNA. Conclusion: Based on these results, it can be concluded that the effectiveness of IFN in eliminating HCV does not seem to be influenced by co‐infection.