Hemodialysis International 2015; 19:353–359
Scholarly Review (Solicited)
Occult hepatitis B among patients with chronic renal failure on hemodialysis from a capital city in northeast Brazil Andrea Martins Melo FONTENELE,1 Juliana Braga Furtado GAINER,2 Daniel Viana da SILVA E SILVA,3 Max Diego CRUZ SANTOS,3 João Victor SALGADO,4 Natalino SALGADO FILHO,1,5 Adalgisa Sousa Paiva FERREIRA3,5 1 Nephrology Service and 3Clinical Research Center, University Hospital, Federal University of Maranhão, São Luís, Brazil; 2Central Public Health Laboratory of Maranhão-Oswaldo Cruz Institute (LACEN), São Luís, Brazil; 4Kidney Disease Prevention Center, University Hospital and Department of Physiological Sciences, Federal University of Maranhão, São Luís, Brazil; 5Department of Medicine I, Federal University of Maranhão, São Luís, Brazil
Abstract Occult hepatitis B (OHB) is characterized by the presence of HBV-DNA in the absence of HBsAg in the serum of patients. Hemodialysis patients are at high risk for hepatitis B virus and there are few data on the prevalence of OHB in this population, mainly in Brazil. Thus, the aim of this study was to determine the prevalence of OHB in patients undergoing hemodialysis. A cross-sectional study was performed, including 301 patients on chronic hemodialysis at two dialysis centers in São Luís (Maranhão), northeast Brazil. Serological tests were performed for HBsAg, anti-HBc, anti-HBs, and anti-HCV using enzyme immunoassays (ELISA); HBV-DNA and HCV-RNA were studied by real-time PCR. The mean age was 49 ± 15 years, and 128 (42%) were female. Serological tests confirmed that all samples were HBsAg negative. Anti-HBc was positive in 114 (38%) patients, anti-HBc and anti-HBs were simultaneously positive in 104 (35%), and anti-HBc alone was positive in 10 (3%). Tests were negative for anti-HBc and anti-HBs in 55 patients (18%). Anti-HBs was the only positive marker in 132 (44%) patients. Anti-HCV was positive in 15 (5%) patients with HCV-RNA present in 14 of them (93%). HBV-DNA was positive in seven cases (2.3%). There was no association of HBV-DNA with age, gender, time on dialysis, previous kidney transplant, or HBV serological pattern, but there was a positive correlation with the presence of anti-HCV (P < 0.001). OHB in chronic renal failure patients on hemodialysis appears to be a relevant finding, suggesting that studying HBV-DNA in this population using sensitive molecular tests should be a recommended course of action, especially in candidates for renal transplant. Key words: Hemodialysis, HBV, HCV, occult HBV, real-time PCR
INTRODUCTION Correspondence to: A. M. M. Fontenele, PharmD, PhD, Nephrology Service, Hospital Universitário da Universidade Federal do Maranhão, Rua Barão de Itapary, 227 Centro, São Luís, Maranhão CEP-65020070, Brazil. E-mail: [email protected]
The hepatitis B virus (HBV) infection is one of the most common infections in the world. It is estimated that there are more than 360 million chronic carriers of the infection, an important cause of liver cirrhosis and
© 2015 International Society for Hemodialysis DOI:10.1111/hdi.12285
353
Fontenele et al.
hepatocellular carcinoma (HCC).1 It has been shown since the 1980s that HBV can be transmitted through blood products and organs donated by individuals negative for HBV surface antigen (HBsAg).2 Such individuals are considered carriers of occult hepatitis B (OHB).3 A greater prevalence of OHB has been identified in populations at higher risk of parenteral infection, immunocompromised patients, carriers of hepatitis C virus (HCV), and patients with cirrhosis and HCC of unknown causes.4–8 OHB can be considered a significant problem in patients with chronic renal failure (CRF) being treated with renal replacement therapy (RRT) because they are susceptible to parenteral infection (due to permanent venous access and immunosuppression)9 and the possibility of reactivating infection when using immunosuppressants after renal transplantation.10,11 The prevalence of OHB in patients on hemodialysis is highly variable and has been related to the magnitude of the presence of chronic infection in the regions studied.12–33 The aim of this study was to determine the prevalence of OHB in patients on hemodialysis in São Luís, Maranhão state, Brazil.
MATERIALS AND METHODS Study population The study was conducted between 2010 and 2013 in the Clinical Research Center of the University Hospital at the Federal University of Maranhão (Hospital Universitário da Universidade Federal do Maranhão—HUUFMA), in the Central Public Health Laboratory of Maranhão-Oswaldo Cruz Institute (Laboratório Central de Saúde Pública do Maranhão-Instituto Oswaldo Cruz—LACEN), Brazil, and in two of the three dialysis units in São Luís, the capital of Maranhão state. The two hemodialysis centers studied comprise more than two-thirds of the city’s population on dialysis. The study was approved by the Ethics Committee of the institution under protocol number 004913/2009-40. All patients from the two units on RRT, hemodialysis modality (with minimum treatment time of 6 months), were interviewed, representing 342 patients. A total of 301 subjects agreed to participate in the study and signed an informed consent form. Blood samples were collected from the subjects and tests performed. All selected patients had records in their charts showing that HBsAg was negative. Data were collected on age, gender, marital status, history of blood transfusion, etiology of renal disease, duration of RRT, complete vaccination
354
against HBV (four doses), and previous history of renal transplantation.
Serological assays Serological tests were performed using the enzyme-linked immunosorbent assay (ELISA) (SIEMENS, Munich, Germany, ADVIA Centaur). All samples collected were screened for serological markers of HBV (HBsAg, antiHBc, and anti-HBs) and HCV (anti-HCV).
HBV real-time polymerase chain reaction (PCR) The Abbott RealTime HBV PCR assay combined with fluorescence detection was conducted using an ABBOTT (Illinois, USA) m2000rT and the procedures were performed according to the manufacturer’s instructions. This assay is standardized according to the World Health Organization (WHO) Guidelines on the International Standard for HBV-DNA (NIBSC code 97/746)34 The results are reported as undetectable or detectable below the limit of quantification and quantified in international units per milliliter (IU/mL). The detection limit of the assay is 10 IU/mL for a 0.5 mL prepared sample.
HCV real-time PCR The Abbott RealTime HCV PCR assay combined with fluorescence detection was employed using an ABBOTT m2000rT according to the manufacturer’s instructions. This assay is standardized according to the Second International Standard for RNA of the HCV (NIBSC code 96/798).35 The results are reported as undetectable or below the detectable limit of quantification and quantified in international units per milliliter (IU/mL). The detection limit of the assay is 12 IU/mL for a 0.5 mL prepared sample.
Statistical analysis The IBM SPSS Statistics version 21.0 software was used for data analysis. Numerical variables were presented as the mean ± standard deviation (SD), and frequencies were presented as numbers (N) and percentages (%). Differences between numerical variables were calculated by Student’s t-test, and differences between nominal variables were calculated using the chi-square or Fisher’s exact test when indicated. The level of significance was set at P ≤ 0.05.
Hemodialysis International 2015; 19:353–359
Occult hepatitis B on hemodialysis
Table 1 Clinical and demographic characteristics of patients on hemodialysis, São Luis, Maranhão, Brazil, 2013 (N = 301)
All samples were negative for HBsAg. Isolated anti-HBs was found in 132 (44%) patients. Anti-HBc and anti-HBs were simultaneously positive in 104 (35%) patients. AntiHBc alone was positive in 10 patients (3%). Fifty-five patients (18%) were negative for anti-HBc and anti-HBs. Because all the patients were submitted to complete HBV vaccination and 132 presented isolated anti-HBs, we may assume that vaccination rate response was 44%. AntiHCV antibodies were detected in 15 (5%) patients, and 14 (93%) of them were positive for HCV-RNA. Screening for HBV-DNA revealed seven patients with a detectable viral load (2.3%) being all from the unit B and with
Scholarly Review (Solicited)
Occult hepatitis B among patients with chronic renal failure on hemodialysis from a capital city in northeast Brazil Andrea Martins Melo FONTENELE,1 Juliana Braga Furtado GAINER,2 Daniel Viana da SILVA E SILVA,3 Max Diego CRUZ SANTOS,3 João Victor SALGADO,4 Natalino SALGADO FILHO,1,5 Adalgisa Sousa Paiva FERREIRA3,5 1 Nephrology Service and 3Clinical Research Center, University Hospital, Federal University of Maranhão, São Luís, Brazil; 2Central Public Health Laboratory of Maranhão-Oswaldo Cruz Institute (LACEN), São Luís, Brazil; 4Kidney Disease Prevention Center, University Hospital and Department of Physiological Sciences, Federal University of Maranhão, São Luís, Brazil; 5Department of Medicine I, Federal University of Maranhão, São Luís, Brazil
Abstract Occult hepatitis B (OHB) is characterized by the presence of HBV-DNA in the absence of HBsAg in the serum of patients. Hemodialysis patients are at high risk for hepatitis B virus and there are few data on the prevalence of OHB in this population, mainly in Brazil. Thus, the aim of this study was to determine the prevalence of OHB in patients undergoing hemodialysis. A cross-sectional study was performed, including 301 patients on chronic hemodialysis at two dialysis centers in São Luís (Maranhão), northeast Brazil. Serological tests were performed for HBsAg, anti-HBc, anti-HBs, and anti-HCV using enzyme immunoassays (ELISA); HBV-DNA and HCV-RNA were studied by real-time PCR. The mean age was 49 ± 15 years, and 128 (42%) were female. Serological tests confirmed that all samples were HBsAg negative. Anti-HBc was positive in 114 (38%) patients, anti-HBc and anti-HBs were simultaneously positive in 104 (35%), and anti-HBc alone was positive in 10 (3%). Tests were negative for anti-HBc and anti-HBs in 55 patients (18%). Anti-HBs was the only positive marker in 132 (44%) patients. Anti-HCV was positive in 15 (5%) patients with HCV-RNA present in 14 of them (93%). HBV-DNA was positive in seven cases (2.3%). There was no association of HBV-DNA with age, gender, time on dialysis, previous kidney transplant, or HBV serological pattern, but there was a positive correlation with the presence of anti-HCV (P < 0.001). OHB in chronic renal failure patients on hemodialysis appears to be a relevant finding, suggesting that studying HBV-DNA in this population using sensitive molecular tests should be a recommended course of action, especially in candidates for renal transplant. Key words: Hemodialysis, HBV, HCV, occult HBV, real-time PCR
INTRODUCTION Correspondence to: A. M. M. Fontenele, PharmD, PhD, Nephrology Service, Hospital Universitário da Universidade Federal do Maranhão, Rua Barão de Itapary, 227 Centro, São Luís, Maranhão CEP-65020070, Brazil. E-mail: [email protected]
The hepatitis B virus (HBV) infection is one of the most common infections in the world. It is estimated that there are more than 360 million chronic carriers of the infection, an important cause of liver cirrhosis and
© 2015 International Society for Hemodialysis DOI:10.1111/hdi.12285
353
Fontenele et al.
hepatocellular carcinoma (HCC).1 It has been shown since the 1980s that HBV can be transmitted through blood products and organs donated by individuals negative for HBV surface antigen (HBsAg).2 Such individuals are considered carriers of occult hepatitis B (OHB).3 A greater prevalence of OHB has been identified in populations at higher risk of parenteral infection, immunocompromised patients, carriers of hepatitis C virus (HCV), and patients with cirrhosis and HCC of unknown causes.4–8 OHB can be considered a significant problem in patients with chronic renal failure (CRF) being treated with renal replacement therapy (RRT) because they are susceptible to parenteral infection (due to permanent venous access and immunosuppression)9 and the possibility of reactivating infection when using immunosuppressants after renal transplantation.10,11 The prevalence of OHB in patients on hemodialysis is highly variable and has been related to the magnitude of the presence of chronic infection in the regions studied.12–33 The aim of this study was to determine the prevalence of OHB in patients on hemodialysis in São Luís, Maranhão state, Brazil.
MATERIALS AND METHODS Study population The study was conducted between 2010 and 2013 in the Clinical Research Center of the University Hospital at the Federal University of Maranhão (Hospital Universitário da Universidade Federal do Maranhão—HUUFMA), in the Central Public Health Laboratory of Maranhão-Oswaldo Cruz Institute (Laboratório Central de Saúde Pública do Maranhão-Instituto Oswaldo Cruz—LACEN), Brazil, and in two of the three dialysis units in São Luís, the capital of Maranhão state. The two hemodialysis centers studied comprise more than two-thirds of the city’s population on dialysis. The study was approved by the Ethics Committee of the institution under protocol number 004913/2009-40. All patients from the two units on RRT, hemodialysis modality (with minimum treatment time of 6 months), were interviewed, representing 342 patients. A total of 301 subjects agreed to participate in the study and signed an informed consent form. Blood samples were collected from the subjects and tests performed. All selected patients had records in their charts showing that HBsAg was negative. Data were collected on age, gender, marital status, history of blood transfusion, etiology of renal disease, duration of RRT, complete vaccination
354
against HBV (four doses), and previous history of renal transplantation.
Serological assays Serological tests were performed using the enzyme-linked immunosorbent assay (ELISA) (SIEMENS, Munich, Germany, ADVIA Centaur). All samples collected were screened for serological markers of HBV (HBsAg, antiHBc, and anti-HBs) and HCV (anti-HCV).
HBV real-time polymerase chain reaction (PCR) The Abbott RealTime HBV PCR assay combined with fluorescence detection was conducted using an ABBOTT (Illinois, USA) m2000rT and the procedures were performed according to the manufacturer’s instructions. This assay is standardized according to the World Health Organization (WHO) Guidelines on the International Standard for HBV-DNA (NIBSC code 97/746)34 The results are reported as undetectable or detectable below the limit of quantification and quantified in international units per milliliter (IU/mL). The detection limit of the assay is 10 IU/mL for a 0.5 mL prepared sample.
HCV real-time PCR The Abbott RealTime HCV PCR assay combined with fluorescence detection was employed using an ABBOTT m2000rT according to the manufacturer’s instructions. This assay is standardized according to the Second International Standard for RNA of the HCV (NIBSC code 96/798).35 The results are reported as undetectable or below the detectable limit of quantification and quantified in international units per milliliter (IU/mL). The detection limit of the assay is 12 IU/mL for a 0.5 mL prepared sample.
Statistical analysis The IBM SPSS Statistics version 21.0 software was used for data analysis. Numerical variables were presented as the mean ± standard deviation (SD), and frequencies were presented as numbers (N) and percentages (%). Differences between numerical variables were calculated by Student’s t-test, and differences between nominal variables were calculated using the chi-square or Fisher’s exact test when indicated. The level of significance was set at P ≤ 0.05.
Hemodialysis International 2015; 19:353–359
Occult hepatitis B on hemodialysis
Table 1 Clinical and demographic characteristics of patients on hemodialysis, São Luis, Maranhão, Brazil, 2013 (N = 301)
All samples were negative for HBsAg. Isolated anti-HBs was found in 132 (44%) patients. Anti-HBc and anti-HBs were simultaneously positive in 104 (35%) patients. AntiHBc alone was positive in 10 patients (3%). Fifty-five patients (18%) were negative for anti-HBc and anti-HBs. Because all the patients were submitted to complete HBV vaccination and 132 presented isolated anti-HBs, we may assume that vaccination rate response was 44%. AntiHCV antibodies were detected in 15 (5%) patients, and 14 (93%) of them were positive for HCV-RNA. Screening for HBV-DNA revealed seven patients with a detectable viral load (2.3%) being all from the unit B and with
