Transfusion transmitted virus in screened United Arab Emirates blood donors

OBJECTIVE

To investigate the rate of infection caused by Torque teno virus (TTV) in United Arab Emirates (UAEs) healthy population as a pilot study in detecting TTV DNA in 100 healthy blood donors.

METHODS

We randomly choose a total of 100 healthy blood donors who attended Zayed Military Hospital, Abu Dhabi, UAE from January 20 to May 30, 2005. We carried out a real-time polymerase chain reaction (PCR) test to detect TTV DNA.

RESULTS

Real-time for TTV was positive in 75 (75%) donors. Eight (73%) non-UAE donors were TTV positive while 67 (75%) were UAEs. Among these donors, 72 (77%) were males and 3 (50%) were females.

CONCLUSION

Our results demonstrated a high prevalence of TTV in UAE.

Prevalence, epidemiological aspects and clinical importance of TT virus infection in Slovakia

The aim of the study was to assess the prevalence, clinical impact and importance of different risk factors of transmission of TTV infection in Slovakia using two PCR methods. Sera of 426 adult persons were examined. TTV DNA was identified by PCR using primers from N22 and untranslated region (UTR) respectively. The established prevalence of TTV tested with N22 and UTR primers according to patients groups was: acute hepatitis of unknown etiology 4 resp. 28 of 37, acute hepatitis B 3 resp. 29 of 38, chronic hepatitis B 11 resp. 41 of 44, chronic hepatitis C 10 resp. 93 of 102, hemodialysis patients 13 resp. 72 of 72, health care workers 0 resp. 27 of 33, control group 8 resp. 83 of 100. Using N22 primers, TTV infection occurred more frequently in chronic hepatitis B group compared with health care workers, if UTR primers were used the group of hemodialysis patients differed significantly from both acute hepatitis groups, health care workers and controls (p < 0.05). From possible risk factors hemodialysis and transfusion count showed notable differences. Bilirubin and aminotransferase levels did not differ between TTV positive and negative groups. No pathogenetic role of TT virus in liver injury was confirmed.

Prevalence of transfusion-transmitted virus infection in patients on maintenance hemodialysis from New Delhi, India

Transfusion-transmitted virus (TTV) has been reported from a number of hemodialysis (HD) units from various countries throughout the world. TTV has been associated with liver diseases, viral hepatitis B, and C. Clinical details and information regarding TTV prevalence from India are insufficient. The prevalence and clinical significance of TTV infection were studied in New Delhi, India in HD patients. Serum samples were derived from 75 patients on maintenance HD, and 75 age- and sex-matched voluntary blood donors were examined for TTV viremia by nested polymerase chain reaction (PCR) using primers derived from UTR (A) region of the TTV genome. The prevalence of TTV DNA in patients on HD (83%) was significantly (p<0.05) higher than in blood donors (43%). Clinical background including the mean age, sex, mean duration of HD, and mean alanine aminotransferase (ALT) levels did not differ significantly between TTV DNA-positive and -negative HD patients. Fifty-four (72%) TTV-positive HD patients and 7 (56%) TTV-negative HD patients had blood transfusion histories (p>0.05). Among TTV-positive patients, Hepatitis B virus (HBV) co-infection was present in 14.2% cases while hepatitis C virus (HCV) co-infection was absent. Persistent elevation of ALT levels was observed in 7(9.3%) HD patients; 3 (43%) of them were TTV positive and 4 (57%) were TTV negative (p>0.05). All 3 TTV-positive patients with elevated ALT levels were co-infected with HBV. Patients with TTV infection alone showed normal ALT levels. Prevalence of TTV infection is high in North Indian patients on maintenance HD. Also, none of the exclusively TTV DNA-positive patients had clinical or biochemical signs of liver disease. TTV seems to spread through parenteral routes. More often, TTV seems to be associated with parenterally transmitted virus HBV, indicating a parenteral mode of TTV transmission. The pathogenicity of TTV remains unclear from the present study.

Presence of TT virus infection in chronic hepatitis patients from a hospital in New Delhi, India

BACKGROUND & OBJECTIVE

The recent discovery of a novel parenterally transmitted, unenveloped, single-stranded DNA virus called TT virus (TTV) in chronic hepatitis patients with unclear pathogenesis throughout the world led us to investigate, its presence in chronic hepatitis patients attending a hospital in New Delhi, India, and to evaluate its role in liver disease.

METHODS

TT virus DNA was investigated in serum samples of 70 patients with various types of chronic hepatitis, and 100 healthy subjects from New Delhi, India by nested PCR using the primers that belonged to UTR (A) region of the genome.

RESULTS

TTV DNA was detected in 6 of 23 patients (26%) with type B chronic hepatitis, 3 of 20 patients (15%) with type C chronic hepatitis, and 12 of 100 subjects (12%) from healthy control group with normal liver function profile tests. None of the 27 non-B, non-C chronic hepatitis patients had TTV DNA positivity. The prevalence of TTV was significantly higher in type-B chronic hepatitis patients as compared to normal subjects (P< 0.05) but comparable to type C chronic hepatitis patients. The clinical course and biochemical profiles of type B, or type C chronic hepatitis patients co-infected with TTV did not differ significantly from those without TTV infection.

INTERPRETATION & CONCLUSION

Interestingly, in chronic hepatitis patients, TTV was always associated with either hepatitis B or C virus indicating a likely parenteral route of transmission. All TTV-positive subjects in healthy control group showed normal clinical and biochemical profiles. Thus, the presence of TTV infection is unlikely to influence the course of chronic hepatitis related to hepatitis B virus (HBV) or hepatitis C virus (HCV) or cause liver diseases in healthy subjects.

SEN virus has an adverse effect on the survival of HIV-positive patients

BACKGROUND

Patients infected with HIV are often coinfected with other viruses.

OBJECTIVE

To investigate the effect of SEN virus (SENV) strains D and H on mortality in HIV-positive patients.

METHODS

A total of 217 HIV-positive patients were analysed retrospectively after first presentation and blood sampling (January 1997 to July 1997) and the effect of coinfection with SENV-D and SENV-H on survival was examined. Analysis periods were the time from blood sampling to the end of follow-up, and the time from diagnosis of HIV infection to the end of study follow-up. SENV-H DNA was measured quantitatively. Prevalences of SENV-D and SENV-H were compared with those in 112 healthy blood donors.

RESULTS

SENV prevalence was significantly higher in HIV-positive patients than in controls (56/217 and 12/112, respectively; P < 0.001). SENV positivity had no influence on survival, but a significant negative influence of SENV-H on survival was observed when SENV-H DNA was > 530 copies/ml, which was the mean SENV-H DNA level found in HIV-negative controls. This adverse effect was found for both studied time periods in a Kaplan-Meier analyses. A multivariate Cox regression analysis, including CD4 cell count, Centers for Disease Control and Prevention stage, age, sex, HIV RNA, highly active antiretroviral therapy and hepatitis C virus status, revealed that a high SENV DNA level was an independent risk factor or indicator for adverse disease outcome.

CONCLUSION

SENV infection is common in HIV-positive patients. High SENV-H DNA levels were predictive for poor survival in HIV-positive patients.

SEN virus: epidemiology and characteristics of a transfusion-transmitted virus

SEN virus (SEN-V) is a blood-borne, single-stranded, nonenveloped DNA virus. Although its prevalence varies by geographic region, it has been detected in as many as 30 percent of postoperative transfusion recipients, compared to 3 percent of postoperative patients who did not receive transfusions. A significant association has been observed between transfusion volume and the occurrence of SEN-V infection. Transmission by transfusion also has been confirmed by the detection of greater than 99 percent homology between SEN-V in donor and recipient sera. Concurrent infections with SEN-V and hepatitis B virus, hepatitis C virus, or human immunodeficiency virus type 1 have been documented, and these observations probably reflect the blood-borne transmission of these viruses as well as SEN-V. Although SEN-V was discovered as part of a search for causes of posttransfusion hepatitis, there is no firm evidence so far that SEN-V infection either causes hepatitis or worsens the course of coexistent liver disease. Nevertheless, SEN-V appears to be transmitted by transfusion, and further studies may reveal more about its role in the future.

Transfusion-transmitted virus is not present in factor IX concentrates commonly used to treat haemophilia B

Transfusion-transmitted virus (TTV) is a potential cause of post-transfusion hepatitis in patients with haemophilia. Plasma-derived clotting factor concentrates currently undergo processes that are effective in removal and inactivation of viruses such as HIV, hepatitis B and C; however, their effectiveness with respect to TTV is unknown. To determine if TTV DNA is present in plasma-derived concentrates of factor IX, we tested 14 lots of Mononine and compared the results with BeneFix. Nucleic acid isolation, followed by a two-round polymerase chain reaction (PCR) and agarose gel analysis indicated that all 17 lots were negative for TTV. Although TTV may be considered an emerging pathogen, no evidence of the virus was detected in the commercially available plasma-derived concentrate of FIX most commonly used to treat haemophilia B.

TT virus among blood donors in Alexandria

TTV is a non enveloped, single-stranded, circular- DNA virus that has been assigned to the Family Circiniviridae. The primary mode of TTV transmission was proposed to be transfusion (and hence its name). Little is known about the clinical significance and the natural history of TTV infection. Hence, responsibility of the virus for specific liver disease is still debated. In our study, we tested ninety five blood donors attending Kom EL-Decka regional blood bank in Alexandria for the presence of TTV DNA in their sera by PCR technique. The same samples were tested for ALT and AST levels by colorimetric technique and for HBsAg and anti-HCV by the ELISA technique. Out of the 95 blood donors, 46 (48.4%) had TTV DNA in their sera. None of the 95 blood donors included in this study was positive for HBsAg, while 22 (23.2%) were anti-HCV positive. Out of the 22 anti-HCV positive blood donors, 13 (59.1%) were TTV DNA positive, while out of the 73 anti-HCV negative blood donors, 33 (45.2%) had TTV DNA in their sera. There was no statistically significant difference between the prevalence of TTV DNA and anti-HCV in blood donors. No biochemical evidence of liver disease potentially linked to the TTV infection was observed in our blood donors who were TTV DNA positive. Furthermore, the occurrence of elevated serum AST and ALT was most often linked to HCV rather than TTV.

Co-infections with hepatitis G and TT virus in patients with chronic hepatitis C in Hungary

The significance of co-infections with novel hepatitis viruses Hepatitis G (GBV-C, HGV) and TT virus (TTV) in chronic hepatitis C is not clear. We determined the prevalence of HGV RNA and TTV DNA in chronic hepatitis C patients and in asymptomatic hepatitis C virus (HCV) carriers, and assessed the influence of these agents on the course of HCV infection. Seventy-seven patients with chronic hepatitis C--50 of them treated with interferon (IFN)--and 33 HCV carriers with normal alanine aminotransferase have been investigated. Previous HBV infection was detected by testing serum HBsAg and aHBc. HGV RNA and TTV DNA were detected by PCR. In the healthy population, the prevalence of anti-HCV was 0.3%, HGV RNA 8.0% and TTV DNA 18.5%. In chronic hepatitis C HGV RNA occurred in 9.09% and TTV DNA in 40.25% of cases. In IFN-treated patients with sustained remission, the frequency of TTV was 20% vs. 45.7% found in non-responders. Among asymptomatic HCV-carriers, the prevalence of HGV RNA was 9.09% and TTV DNA 75.7%. Neither HGV RNA nor TTV DNA had apparent effect on the HCV infection. TTV was detected with the lowest frequency in persons with sustained remission due to IFN, suggesting antiviral effect of IFN on TTV.

TT virus infection in acute and chronic liver diseases and in patients regularly receiving blood products in Belgium

BACKGROUND

TT viruses are single-stranded DNA viruses, suggested to be involved in non A-E hepatitis. We studied the prevalence of TTV infection in acute or chronic hepatitis in Belgium in comparison with that in blood donors and in patients regularly receiving blood products.

METHODS

TTV-DNA was detected by PCR using the primer set of Takahashi et al (1998) or a nested-PCR specific for genotype-2, because it had been reported that this subtype might be more pathogenic (Tagger et al. 1999).

RESULTS

TTV-DNA was present in 49% of 128 patients with chronic hepatitis C, in 54% of 54 with chronic hepatitis B and in 54% of 24 with acute liver failure. This prevalence is similar to the 47% in 127 patients with clotting disorders, or the 64% in 103 undergoing chronic haemodialysis, but lower than the 29.7% found in 340 healthy blood donors. Significant differences in clinical or biochemical characteristics between TTV- positive or TTV-negative patients could not be substantiated. The genotype-2 subgroup comprised 3.9%, but they also did not differ from non genotype-2 patients.

CONCLUSIONS

The prevalence of TTV infection was higher in patients than in healthy blood donors. Its clinical significance remains questionable since clinical and biochemical characteristics were not different between TTV positive and TTV negative patients. The higher prevalence of TTV in patients might be related to parenteral transmission, but the relatively high prevalence in healthy blood donors points to an additional presumably faeco-oral infection. The presence of TTV in animals suggests that infection might also originate from food. Long term follow-up will have to define whether co-infection with TTV eventually alters the natural history of chronic hepatitis.

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 of TT 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 (1000 mg-1200 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, TTV infection was detected in 10/15 (66.6%) of HCV-infected patients. Loss of serum TTV 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.

TT virus-positive hepatocellular carcinoma arising from non-cirrhotic liver in an elderly man

A 43-mm hepatic tumor was incidentally detected by computed tomography in a 72-year-old man. Liver function test results were normal. Serum hepatitis B, C and G viruses were negative, while serum TT virus was positive. Autoantibodies were negative. The patient had no history of alcohol consumption. The tumor was found to be a moderately differentiated hepatocellular carcinoma (HCC) from a resected specimen. Neither lobular inflammation nor fibrosis was observed in the surrounding liver. Intrahepatic hepatitis B virus was not detected. This is a case of non-B, non-C HCC positive for only TT virus arising from a non-cirrhotic liver.

Prevalence of transfusion transmitted virus infection and its effect on renal graft survival in renal transplant recipients

OBJECTIVE

Little is known about the prevalence of transfusion transmitted virus (TTV) infection in renal transplant recipients (RTxs) and its effects on allograft survival. We investigated the prevalence of TTV and its effects on liver injury and graft survival in RTxs.

MATERIAL AND METHODS

The study was performed in 33 consecutive RTxs (8 females, 25 males) and 100 blood donors (35 females, 65 males). A nested polymerase chain reaction was used to detect TTV DNA in serum. Serum creatinine and alanine aminotransferase (ALT) levels and 24-h protein excretion were determined in both TTV-positive and-negative patients. The total number of blood transfusions, the duration of hemodialysis and the total duration after transplantation were recorded in RTxs. In addition, hepatitis B surface antigen (HbsAg), anti-hepatitis C virus (HCV) and hepatitis G virus DNA antibodies were determined in all patients.

RESULTS

TTV DNA was detected in 51.5% of RTxs and in 7% of the control group and this difference was statistically significant (p < 0.01). In the RTx group, 64.7% of TTV-positive and 56.2% of TTV-negative patients had undergone a previous blood transfusion. However, the blood transfusion replacement rate, total duration of dialysis therapy and posttransplant period did not differ between these two groups. Five (15.1%) patients in the RTx group had abnormal liver function tests (ALT >40 IU/l). Of these patients, 2 were anti-HCV-positive, 1 was HBsAg-positive and anti-HCV- plus TTV DNA-positive and the serologic tests of the remaining 2 patients were all negative. Among the TTV-positive patients, 2 (11.7%) were anti-HCV-positive, 1 (5.8%) was HBsAg-positive and 3 (17.6%) were HGV DNA-positive. The baseline serum creatinine levels did not differ significantly between the TTV-positive and-negative patients, being 1.5 +/- 0.6 and 1.4 +/- 0.6 mg/dl, respectively ( p > 0.05). Two of the TTV-positive patients and 1 of the TTV-negative patients had proteinuria. A 1-year follow-up of TTV-positive and-negative patients demonstrated neither acute nor chronic graft rejection.

CONCLUSION

In RTxs, TTV infection was more prevalent than in the normal population. In our patients the virus did not have an important effect on renal graft rejection and did not cause liver injury. However, the question of whether TTV infection may affect graft survival requires further long-term investigation in larger groups.

No effect of transfusion transmitted virus viremia on the distribution and activation of peripheral lymphocytes in hemodialyzed patients

AIM

We aimed to examine the distribution and activation of peripheral T cells in TTV positive (n = 32) and negative (n = 17) hemodialyzed patients. The control group (n = 20) consisted of healthy blood donors.

METHOD

TTV-DNA was detected by seminested PCR. CD3, CD4, CD8, CD19, CD56, CD3/HLA-DR, CD3/CD69 and the Th1/Th2 ratio of T cells were analyzed by flow cytometry. Circulating IFN-gamma, IL-2, IL-4, IL-6, IL-10, IL-13, TNF-alpha, TGF-beta levels were measured by ELISA in the sera.

RESULTS

There was no difference between the CD3, CD4, CD8 and CD19 values of HD subjects. In addition, the expression of both activation markers, HLA-DR and CD69, was significantly elevated in the TTV-positive and -negative HD groups compared to the controls, but not showing any difference from each other. The measurements of intracellular cytokines showed the enhanced occurrence of INF-gamma + CD4 T cells, and decreased appearance of IL-4 + CD4 lymphocytes in the HD groups without any significant difference between the TTV virus positive and negative patients. In addition, HD also elevated the expression of IL-10 in CD4 and CD8 (Th2) cells. There were only two significant changes in the levels of circulating cytokines: (a) IL-2 increased; (b) IL-13 decreased in both groups of HD patients compared to the controls, independently of TTV positivity or negativity.

CONCLUSIONS

We assume that transfusion-transmitted virus does not cause any specific change in the distribution and activation of lymphocytes in the peripheral blood of hemodialyzed patients. Hemodialysis itself, however, results in a significant activation of peripheral T cells with the domination of increased production of Th1 type cytokines, IFN-gamma, IL-2, in contrast to the decreased synthesis of Th2 type cytokines, IL-4 and IL-13. Furthermore, the increased expression of IL-10 in the CD4 and CD8 cells of HD patients can be the sign of a contraregulatory Th2 activation as an answer on the Th1 effect.

Investigation of TT virus in the etiology of pediatric acute lymphoblastic leukemia

Infectious agents have been implicated in the pathogenesis of pediatric acute lymphoblastic leukemia (ALL). A novel human DNA virus, TT virus (TTV), has been identified in children possessing characteristics as an etiologic agent, making the virus a potential candidate. Analysis of specimens from children with ALL was performed to determine if an association exists. Archived specimens (79 peripheral blood mononuclear cells, PBMC/bone marrow cells, BMC, and 125 cerebrospinal fluid, CSF) obtained at diagnosis and during therapy from 28 pediatric patients were tested for TTV. All of the diagnostic BMC/PBMC were negative for TTV, but 7 patients had follow-up specimens that converted to TTV positivity. TTV was not detected in any CSF. The absence of TTV at diagnosis suggests TTV is unlikely to be causally associated with ALL in the cases analyzed. However, the data support TTV transmission through blood products and suggest that the CNS is not a sanctuary site for TTV.

New prevalence estimate of TT virus (TTV) infection in low- and high-risk population from São Paulo, Brazil

The prevalence of TT virus (TTV) infection was investigated by Polymerase Chain Reaction (PCR) in low- (blood donors and healthy children/adolescents) and high-risk (hemophiliacs) groups from São Paulo, Brazil. Primers based on the untranslated region (UTR) of the viral genome proved to be much more ubiquitous, leading to much higher frequencies for both groups (>or= 81%) than the earlier N22-PCR directed to the open reading frame 1 (blood donors, 5.5%, and hemophiliacs, 42.3%). The UTR-PCR also revealed an interesting profile for healthy children/adolescents: very high prevalence at the early years and significant decrease in male teenagers. The N22-PCR, in turn, demonstrated higher frequency in hemophiliacs treated with fresh blood products (58%), than in those treated with virus-inactivated clotting factors (9.4%) and blood donors (5.5%).

Investigation of transfusion transmitted viruses in cases clinically suspected of posttransfusion hepatitis with undetermined ethiology

Transfusion transmitted viruses (TTV) were investigated in cardiac surgery cases who were previously transfused with blood and/or blood products and were suspected of having posttransfusion hepatitis (PTH) based on the results of physical examination, clinical findings, biochemical blood test results and in a smaller number, on radiological results. They were identified as having non-A-C hepatitis based on serological or molecular test methods. In this study, out of 90 cases suspected for PTH and non-A-C, 78 (86.7%) were male, 12 (13.3%) were female and their ages were between 17 and 67. Ninety healthy blood donors, who donated blood for the first time and had never had a transfusion, were selected as the control group. They had alanine aminotransferase (ALT) levels < 40 U, were seronegative for hepatitis B virus (HBV) and hepatitis C virus (HCV). Seventy-seven were immune, and 13 were seronegative for hepatitis A virus (HAV). In this study, TTV-deoxyribonucleic acid (DNA) investigation was performed by the polymerase chain reaction (PCR) method suggested by Takahashi et al. with 5' GCT ACG TCA CTA ACC ACG TG 3' (T801) and 5' CTG CGG TGT GTA AAC TCA CC 3' (T935) primers. TTV-DNA was found to be positive in 21 (23.3%) of the patient group and 4 (4.4%) of the control group (p < 0.05). In the patients determined to be TTV-DNA positive, the admission time following transfusion was a minimum of 3, and a maximum of 15 (average 7) weeks. The average ALT levels detected at the time of admission did not show a difference between TTV-DNA positive and negative cases (p > 0.05). However the ALT levels had a tendency to rise and reached their highest level nine weeks after transfusion in the TTV-DNA positive cases, although in two cases the ALT levels decreased to normal value after the 13th week. During the 24 month follow up of the TTV-DNA positives all cases except one were positive at the end of this period. The results of this study are the same as those reported in the literature suggesting that TTV-DNA, excluding the main viral agents which are known to cause PTH, can be determined in transfused PTH or non-transfused asymptomatic patients in varying ratios. In order to define the epidemiological properties and hepatic-extrahepatic pathologies more clearly we have looked for evidence of the viral agent, which probably contaminates both by transfusion and non-transfusion routes. It is suggested that, in addition to the case groups in this study, new clinical studies are necessary including transfused but non-PTH patients.

Prevalence of TT virus in a CAPD population

TT virus (TTV) has recently been identified in patients with post-transfusion non-A, non-G hepatitis. It is reported to be common in patients with a variety of liver diseases and with history of transfusion. Its pathogenesis in chronic liver diseases remains unclear. In this study, we have determined the prevalence of TTV in a continuous ambulatory peritoneal dialysis (CAPD) population and related its prevalence with history of previous hemodialysis, transfusion, HCV positivity and serum alanine amino-transferase (ALT) levels. TTV was detected in 44% of 63 CAPD patients and 30% of 43 healthy controls (p = 0.15). Frequency of TTV was similar in previously hemodialysed and never hemodialysed (8/14, 57% vs. 20/40, 41%, p = 0.15) and previously transfused and non-transfused (7/19, 37% vs. 15/44, 34%) CAPD patients. Prevalence of TTV was also similar in HCV(+) and HCV(-) patients. Serum ALT levels were 19 +/- 16 and 20 +/- 12 U/l in TTV(+) and TTV(-) patients, respectively. These results indicate that prevalence of TTV in a CAPD population is similar to healthy controls, and other routes of transmission in addition to parenteral routes might be involved in the transmission of TTV.

Coinfection of TT virus and response to interferon therapy in patients with chronic hepatitis B or C

AIM

To investigate the serum positive percentage of TT virus (TTV) in patients with chronic hepatitis B or C and the response of the coinfected TTV to interferon (IFN) during IFN therapy for chronic hepatitis B and C.

METHODS

We retrospectively studied the serum samples of 70 patients with chronic hepatitis who had received IFN-alpha therapy from January 1997 to June 2000, which included 40 cases of hepatitis B and 30 hepatitis C. All the patients had been followed up for at least 6 months after the end of IFN therapy. The serum TTV DNA was detected using the polymerase chain reaction (PCR) before and every month during the course of IFN treatment.

RESULTS

TTV infection was detected in 15% (6/40) of the chronic hepatitis B group and 30% (9/30) of the chronic hepatitis C group. Loss of serum TTV DNA during IFN therapy occurred in 3 of 6 patients (50%) and 6 of 9 (67%) of hepatitis B and C groups, respectively. Seronegativity of TTV was found all during the first month of IFN therapy in the 9 patients. There was no correlation between the seroconversion of TTV and the biochemical changes of the patients.

CONCLUSION

TTV is not infrequently coinfected in patients with chronic hepatitis B and C in Taiwan, and more than half of the TTV infections are IFN-sensitive. However, the loss of serum TTV DNA does not affect the clinical course of the patients with chronic hepatitis B or C.

Infectious hepatitis C, hepatitis G, and TT virus: review and implications for dentists

In the past 10 years, hepatitis C and G viruses have been identified, and in the last two years a further parenterally transmitted agent, termed TT virus (TTV), has been discovered. These viruses have a worldwide distribution and frequently cause chronic infection. The purpose of this article was to promote an understanding of these viral agents and their relevance in dental practice. Infected patients may develop a chronic carrier state without clinical disease or may develop liver disease, and may have related oral conditions. Dental providers will see a growing number of patients with HCV/HGV and possibly TTV infection. All of these patients require appropriate infection control measures during dental treatment.

[Relationship between TT virus infection and hepatocellular carcinoma]

OBJECTIVE

To clarify the relationship between TT virus (TTV) infection and the development of hepatocellular carcinoma (HCC).

METHODS

TTV was examined in sera of 112 patients with HCC and 95 patients with chronic liver disease (CLD) without HCC. 30 patients without liver disease were examined as control. TTV DNA was detected by the second generation of TTV PCR primers (NG059, NG061 and NG063) after extraction of DNA from 50 microliters serum. The relationship between TTV infection and clinical features of each group patients was analyzed.

RESULTS

TTV DNA was detected in 17.86% (20/112) of HCC patients, and this prevalence in HCC patients was not significantly higher than that of TTV DNA in CLD patients (15.78%, 15/95). There were no significant differences in age, gender, tumor factors (size, TNM classification and markers) and other hepatitis virus markers between TTV-positive and TTV-negative in HCC and CLD patients, except history of blood transfusion [(80.00% vs 35.87% (P < 0.05) in HCC patients and 73.33% vs 27.50% (P < 0.05) in CLD patients)] and ALT [(93 +/- 27) IU/L vs (68 +/- 31) IU/L (P < 0.05) in HCC patients]. It seemed that TTV did not do any harm to the liver function of patients who infected with HBV or HCV, except for elevating ALT level in such a kind of HCC patients.

CONCLUSION

Although TTV could do harm to the liver function of HCC patients, it does not contribute to the development of HCC from CLD.