- Email: [email protected]
Transfusion-transmitted virus infection in renal transplant recipients
Transfusion-Transmitted Virus Infection in Renal Transplant Recipients M. Usta, K. Dilek, A. Ersoy, R. Mıstık, Y. Heper, M. Gullulu, M. Yavuz, B. Oktay, and M. Yurtkuran
T
HE TRANSFUSION-TRANSMITTED virus (TTV) described recently was first detected in peripheral blood and liver tissue of symptomatic patients with posttransfusion hepatitis non A-G.1,2 TTV is presumed to be an unenveloped, circular, negative stranded DNA virus containing a genome of 3852 bases. It is proposed that TTV is a member of a new virus family that infects humans, tentatively named the Circinoviridae.3 TTV infection in humans occurs worldwide, and its prevalence is regionally very different.4 It was first isolated from patients with posttransfusion hepatitis.2 Viremia may be transient or persistent, and viremic individuals are often asymptomatic. Its transmission occurs not only by blood transfusion, but also by non-parenteral infection.5 Renal transplant (RTx) recipients can be infected with TTV because of exposure to the frequent blood transfusions during hemodialysis treatments. However, not much data is available about TTV infection in renal transplant recipients.6,7 Therefore, we investigated the prevalence of TTV and the relation to liver diseases in these populations. PATIENTS AND METHODS Our study includes 33 RTx recipients (8 women, 25 men) and 100 blood donors (55 women, 45 men) of mean ages 34 ⫾ 9 years and 36 ⫾ 6 years, respectively. The mean transplant duration of RTx recipients was 20.3 ⫾ 19.0 months. Except for 5 patients, serum alanine aminotransferase (ALT) activities were normal in all subjects (26 ⫾ 14 U/L in RTx recipients). Twenty patients had a history of blood transfusion. HBsAg, anti– hepatitis C virus (HCV) and HGV-RNA were positive in 6%, 9%, and 18.1% of patients, respectively. All patients were seronegative for anti-HIV antibody. Five patients (15.1%) had abnormal liver function tests (ALT ⬎ 40 IU/liter). All blood donors had anti-HCV, anti-HBc, and HBsAg negativity and none had a blood transfusion history. EDTA plasma samples were obtained from all cases. TTV DNA was detected by polymerase chain reaction (PCR) using seminested primers. The master mixture contained Taq polymerase, MgCL2, dntp (Boehringer, Mannheim, Germany), and NGO59 (5⬘ACA GAC AGA GGA GAA GGC AAC ATG-3⬘) and NGO63 (5-CTG GCA TTT TAC CAT TTC CAA AGTT-3). We performed the first PCR with 35 cycles (temperature: 30 seconds at 94°C, 45 seconds at 60°C, 45 seconds at 72°C for PCR, and an additional final cycle of 7 minutes). The second PCR also was performed at the same temperatures as the first test, using the primers NGO61 (5⬘-GGC AAC ATG YTR TGG ATA GAC TGG-3⬘) and NGO63 with 25 cycles. The products of the first (286
base pair [bp]) and the second PCR (271 bp) were demonstrated by gel electrophoresis after staining with ethidium bromide.8
RESULTS
TTV DNA was positive in 17 (51.5%) of the RTx recipients and in 12 (12%) of the blood donors, a statistically significant difference (P ⬍ .0001). Among the 20 RTx recipients who had history of blood transfusion, 9 (46.1%) were TTV DNA–positive. There were no significant differences between the mean total number of blood transfusions, the mean duration of dialysis, and the mean posttransplantation period in the TTV DNA–positive and –negative groups (2.2 ⫾ 2.4 units vs 1.8 ⫾ 2.4 units, 26 ⫾ 43 months vs 16 ⫾ 14 months, and 39 ⫾ 35 months vs 39 ⫾ 44 months, respectively). In addition, there was no difference between the ages and genders of both groups. Among 17 patients who had TTV DNA–positivity, 2 had anti-HCV–positivity, 1 had HBsAg-positivity, and 3 had HGV DNA–positivity. In the TTV DNA–negative group, 1 patient had anti-HCV– positivity, 1 had HBsAg, and 3 had HGV DNA–positivity. Among all patients, 5 had abnormal liver function test results. Of these, 2 had anti-HCV, 1 had HBs Ag and TTV DNA–positivity, and the remaining 2 patients’ serologic tests were negative. DISCUSSION
The association between TTV infection and hepatitis remains controversial.9 Concomitant infection with TTV and hepatitis B virus (HBV) or HCV is common.10 However, the effect of TTV infection on chronic HBV or HCV is unknown. Kao et al10 reported that co-infection with TTV did not affect the clinicopathological course of chronic HBV or HCV and the response to interferon alpha therapy. The prevalence of TTV-positivity in uremic patients in various studies ranges from 29.5% to 61%, which is much higher than that reported among the normal population From the Department of Nephrology (M.U., K.D., A.E., M.G., M.Y., M.Y.), Department of Microbiology (R.M., Y.H.), and Department of Urology (B.O.), Medical Faculty, Uludagˇ University Medical School, Bursa, Turkey. Address reprint requests to Kamil Dilek, Department of Nephrology, Uludagˇ University Medical School, 16059 Gorukle, Bursa, Turkey. E-mail: [email protected]
© 2002 by Elsevier Science Inc. 360 Park Avenue South, New York, NY 10010-1710
0041-1345/02/$–see front matter PII S0041-1345(02)03555-8
Transplantation Proceedings, 34, 3209 –3210 (2002)
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(range, 1% to 12%).9,11 Recently, Ikeuchi et al12 investigated the frequency of super-infection of this virus and HCV, which is known to be endemic among hemodialysis patients, and reported no deleterious effect of TTV on HCV-induced chronic liver disease. Wolff et al5 found that the prevalence of TTV was 25% among 495 heart transplant HTx recipients. The frequency of TTV-positivity (51.5%) in our RTx recipients was greater than that of the blood donors or HTx recipients. We have no data about TTV DNA–positivity of our patients before transplantation. We could not demonstrate any relationship between TTV viremia and the total number of blood transfusions or the duration of hemodialysis or the time after the transplantation. Michitaka et al7 did not find a clear association between TTV infection and posttransplantation liver function abnormality. In our series, we did not observe any fluctations in serum ALT levels of TTV DNA–positive patients in routine follow-up, which may suggest a lack of hepato-pathogenicity of the virus. However, Yokosuka et al6 suggested that special strains of TTV could produce abnormalities of the liver function test results. But, in our patients, TTV infection did not adversely affect clinical outcomes. The cause of a high prevalence among our immunosuppressed RTx recipient population is unclear. A possible reason for the high prevalence of TTV in RTx recipients might be activation of the virus by immunosuppression therapy. Also, the renal allograft may be a source of TTV infection. The high prevalence of TTV positivity in our RTx recipients who did not receive prior blood transfusions suggests a non-parenteral transmission of the virus
USTA, DILEK, ERSOY ET AL
in addition to the parenteral route. Our data failed to reveal any significant association of TTV virus with anti-HCV, anti-HBs, and HGV DNA–positivity. Consequently, in this study we found that TTV DNA– positivity in RTx recipients was high in contrast to healthy individuals. The RTx recipients can be considered to be at risk for TTV infection but hepatic involvement remains obscure, warranting further investigations. Renal survival in TTV-positive RTx recipients should be investigated in further detail. REFERENCES 1. Nishizawa T, Okamoto H, Konishi K, et al: Biochem Biophys Res Commun 241:92, 1997 2. Okamoto H, Nishizawa T, Kato N, et al: Hepatol Res 10:1, 1998 3. Mushahwar IK, Erker JE, Muerhoff AS, et al: Proc Natl Acad Sci U S A 96:3177, 1999 4. Prescott LE, Simmonds P: N Engl J Med 339:776, 1998 5. Wolff C, Diekmann A, Boomgaarden M, et al: Transplantation 69:351, 2000 6. Yokosuka O, Ikeuchi T, Kanda T, et al: Transplantation 70:1194, 2000 7. Michitaka K, Horiike N, Matsubara H, et al: Hepatol Res 18:122, 2000 8. Okamoto H, Akahane Y, Ukita M, et al: J Med Virol 56:128, 1998 9. Chan YJ, Hsu YH, Chen MC, et al: J Microbiol Immunol Infect 33:14, 2000 10. Kao JH, Chen W, Chen PJ, et al: J Med Virol 60:387, 2000 11. Tanaka H, Miyano M, Yukawa S: Nippon Rinsho 57:1410, 1999 12. Ikeuchi T, Okuda K, Yokosuka O, et al: J Gastroenterol Hepatol 14:796, 1999
T
HE TRANSFUSION-TRANSMITTED virus (TTV) described recently was first detected in peripheral blood and liver tissue of symptomatic patients with posttransfusion hepatitis non A-G.1,2 TTV is presumed to be an unenveloped, circular, negative stranded DNA virus containing a genome of 3852 bases. It is proposed that TTV is a member of a new virus family that infects humans, tentatively named the Circinoviridae.3 TTV infection in humans occurs worldwide, and its prevalence is regionally very different.4 It was first isolated from patients with posttransfusion hepatitis.2 Viremia may be transient or persistent, and viremic individuals are often asymptomatic. Its transmission occurs not only by blood transfusion, but also by non-parenteral infection.5 Renal transplant (RTx) recipients can be infected with TTV because of exposure to the frequent blood transfusions during hemodialysis treatments. However, not much data is available about TTV infection in renal transplant recipients.6,7 Therefore, we investigated the prevalence of TTV and the relation to liver diseases in these populations. PATIENTS AND METHODS Our study includes 33 RTx recipients (8 women, 25 men) and 100 blood donors (55 women, 45 men) of mean ages 34 ⫾ 9 years and 36 ⫾ 6 years, respectively. The mean transplant duration of RTx recipients was 20.3 ⫾ 19.0 months. Except for 5 patients, serum alanine aminotransferase (ALT) activities were normal in all subjects (26 ⫾ 14 U/L in RTx recipients). Twenty patients had a history of blood transfusion. HBsAg, anti– hepatitis C virus (HCV) and HGV-RNA were positive in 6%, 9%, and 18.1% of patients, respectively. All patients were seronegative for anti-HIV antibody. Five patients (15.1%) had abnormal liver function tests (ALT ⬎ 40 IU/liter). All blood donors had anti-HCV, anti-HBc, and HBsAg negativity and none had a blood transfusion history. EDTA plasma samples were obtained from all cases. TTV DNA was detected by polymerase chain reaction (PCR) using seminested primers. The master mixture contained Taq polymerase, MgCL2, dntp (Boehringer, Mannheim, Germany), and NGO59 (5⬘ACA GAC AGA GGA GAA GGC AAC ATG-3⬘) and NGO63 (5-CTG GCA TTT TAC CAT TTC CAA AGTT-3). We performed the first PCR with 35 cycles (temperature: 30 seconds at 94°C, 45 seconds at 60°C, 45 seconds at 72°C for PCR, and an additional final cycle of 7 minutes). The second PCR also was performed at the same temperatures as the first test, using the primers NGO61 (5⬘-GGC AAC ATG YTR TGG ATA GAC TGG-3⬘) and NGO63 with 25 cycles. The products of the first (286
base pair [bp]) and the second PCR (271 bp) were demonstrated by gel electrophoresis after staining with ethidium bromide.8
RESULTS
TTV DNA was positive in 17 (51.5%) of the RTx recipients and in 12 (12%) of the blood donors, a statistically significant difference (P ⬍ .0001). Among the 20 RTx recipients who had history of blood transfusion, 9 (46.1%) were TTV DNA–positive. There were no significant differences between the mean total number of blood transfusions, the mean duration of dialysis, and the mean posttransplantation period in the TTV DNA–positive and –negative groups (2.2 ⫾ 2.4 units vs 1.8 ⫾ 2.4 units, 26 ⫾ 43 months vs 16 ⫾ 14 months, and 39 ⫾ 35 months vs 39 ⫾ 44 months, respectively). In addition, there was no difference between the ages and genders of both groups. Among 17 patients who had TTV DNA–positivity, 2 had anti-HCV–positivity, 1 had HBsAg-positivity, and 3 had HGV DNA–positivity. In the TTV DNA–negative group, 1 patient had anti-HCV– positivity, 1 had HBsAg, and 3 had HGV DNA–positivity. Among all patients, 5 had abnormal liver function test results. Of these, 2 had anti-HCV, 1 had HBs Ag and TTV DNA–positivity, and the remaining 2 patients’ serologic tests were negative. DISCUSSION
The association between TTV infection and hepatitis remains controversial.9 Concomitant infection with TTV and hepatitis B virus (HBV) or HCV is common.10 However, the effect of TTV infection on chronic HBV or HCV is unknown. Kao et al10 reported that co-infection with TTV did not affect the clinicopathological course of chronic HBV or HCV and the response to interferon alpha therapy. The prevalence of TTV-positivity in uremic patients in various studies ranges from 29.5% to 61%, which is much higher than that reported among the normal population From the Department of Nephrology (M.U., K.D., A.E., M.G., M.Y., M.Y.), Department of Microbiology (R.M., Y.H.), and Department of Urology (B.O.), Medical Faculty, Uludagˇ University Medical School, Bursa, Turkey. Address reprint requests to Kamil Dilek, Department of Nephrology, Uludagˇ University Medical School, 16059 Gorukle, Bursa, Turkey. E-mail: [email protected]
© 2002 by Elsevier Science Inc. 360 Park Avenue South, New York, NY 10010-1710
0041-1345/02/$–see front matter PII S0041-1345(02)03555-8
Transplantation Proceedings, 34, 3209 –3210 (2002)
3209
3210
(range, 1% to 12%).9,11 Recently, Ikeuchi et al12 investigated the frequency of super-infection of this virus and HCV, which is known to be endemic among hemodialysis patients, and reported no deleterious effect of TTV on HCV-induced chronic liver disease. Wolff et al5 found that the prevalence of TTV was 25% among 495 heart transplant HTx recipients. The frequency of TTV-positivity (51.5%) in our RTx recipients was greater than that of the blood donors or HTx recipients. We have no data about TTV DNA–positivity of our patients before transplantation. We could not demonstrate any relationship between TTV viremia and the total number of blood transfusions or the duration of hemodialysis or the time after the transplantation. Michitaka et al7 did not find a clear association between TTV infection and posttransplantation liver function abnormality. In our series, we did not observe any fluctations in serum ALT levels of TTV DNA–positive patients in routine follow-up, which may suggest a lack of hepato-pathogenicity of the virus. However, Yokosuka et al6 suggested that special strains of TTV could produce abnormalities of the liver function test results. But, in our patients, TTV infection did not adversely affect clinical outcomes. The cause of a high prevalence among our immunosuppressed RTx recipient population is unclear. A possible reason for the high prevalence of TTV in RTx recipients might be activation of the virus by immunosuppression therapy. Also, the renal allograft may be a source of TTV infection. The high prevalence of TTV positivity in our RTx recipients who did not receive prior blood transfusions suggests a non-parenteral transmission of the virus
USTA, DILEK, ERSOY ET AL
in addition to the parenteral route. Our data failed to reveal any significant association of TTV virus with anti-HCV, anti-HBs, and HGV DNA–positivity. Consequently, in this study we found that TTV DNA– positivity in RTx recipients was high in contrast to healthy individuals. The RTx recipients can be considered to be at risk for TTV infection but hepatic involvement remains obscure, warranting further investigations. Renal survival in TTV-positive RTx recipients should be investigated in further detail. REFERENCES 1. Nishizawa T, Okamoto H, Konishi K, et al: Biochem Biophys Res Commun 241:92, 1997 2. Okamoto H, Nishizawa T, Kato N, et al: Hepatol Res 10:1, 1998 3. Mushahwar IK, Erker JE, Muerhoff AS, et al: Proc Natl Acad Sci U S A 96:3177, 1999 4. Prescott LE, Simmonds P: N Engl J Med 339:776, 1998 5. Wolff C, Diekmann A, Boomgaarden M, et al: Transplantation 69:351, 2000 6. Yokosuka O, Ikeuchi T, Kanda T, et al: Transplantation 70:1194, 2000 7. Michitaka K, Horiike N, Matsubara H, et al: Hepatol Res 18:122, 2000 8. Okamoto H, Akahane Y, Ukita M, et al: J Med Virol 56:128, 1998 9. Chan YJ, Hsu YH, Chen MC, et al: J Microbiol Immunol Infect 33:14, 2000 10. Kao JH, Chen W, Chen PJ, et al: J Med Virol 60:387, 2000 11. Tanaka H, Miyano M, Yukawa S: Nippon Rinsho 57:1410, 1999 12. Ikeuchi T, Okuda K, Yokosuka O, et al: J Gastroenterol Hepatol 14:796, 1999