Journal of Viral Hepatitis, 2014, 21, 818–823
doi:10.1111/jvh.12219
Maternal ABO and rhesus blood group phenotypes and hepatitis B surface antigen carriage T. T. Lao, D. S. Sahota, M.-K. Chung, T. K. W. Cheung, Y. K. Y. Cheng and T. Y. Leung Department of Obstetrics & Gynaecology, The Chinese University of Hong Kong, Prince of Wales Hospital, Shatin, Hong Kong, China Received July 2013; accepted for publication September 2013
SUMMARY. In view of a persistently high prevalence of hepatitis B surface antigen (HBsAg) carriage in our obstetric population, we examined the association between HBsAg carriage with maternal ABO and rhesus (Rh) blood group phenotypes determined at routine antenatal screening. In a retrospective study, the antenatal screening results of women booked for confinement between 1998 and 2011 in our hospital were examined for the relationship between HBsAg carriage with the ABO and rhesus blood groups, taking into account also the effects of advanced maternal age (≥35 years) and parity status (nulliparous or multiparous), and year of birth before or following the availability of the hepatitis B vaccine (1984). HBsAg carriage was found in 9.9%, 9.6%, 9.1% and 10.2% (P = 0.037) for group-A (n = 20 581 or 26.1%), -B (n = 20 744 or 26.4%), -AB (n = 5138 or 6.5%) and -O (n = 32 242 or 41.0%) among the 78 705 women in the study cohort.
INTRODUCTION The prevalence of chronic hepatitis B virus (HBV) infection is much higher in the Asian and Chinese populations, being 20% or more even among the immigrants to western countries [1–3]. In Hong Kong, the maternal carriage rate for hepatitis B surface antigen (HBsAg) remains around 10% [4,5], despite the introduction of the hepatitis B vaccine in the 1980s [6,7]. We suspect that this could be related to phenotypic differences among different populations, such as the different frequency of the ABO and Rhesus (Rh) blood groups. In China and Hong Kong, the group-O phenotype of the ABO blood type is found in 50.0% [8] and 41.83% [9], respectively, compared with 44.0% in both the United Kingdom [10] and United States Abbreviation: AA, Australian antigen; HBsAg, hepatitis B surface antigen; HBV, hepatitis B virus; HCC, hepatocellular carcinoma; HCV, hepatitis C virus. Correspondence: Prof. Terence T. Lao, MD, Department of Obstetrics & Gynaecology, Prince of Wales Hospital, Shatin, Hong Kong SAR, China. E-mail: [email protected]
Rhesus negativity was found in 0.6%, and HBsAg carriage was 12.3% and 9.8%, respectively, for the Rh-negative and Rh-positive women (P = 0.071). Carriage rate between group-O and non-O was influenced by nulliparity, age ≥35 years and Rh-positive status. Regression analysis indicated that group-B (P = 0.044, aOR = 1.062, 95% CI 1.002–1.127) and group-AB (P = 0.016, aOR = 1.134, 95% CI 1.024–1.256) were associated with HBsAg carriage. Blood groups-B and -AB are associated with increased hepatitis B virus (HBV) infection in our population, and further studies are warranted to elucidate the implications of this on the sequelae of HBV infection. Keywords: ABO blood group, Chinese, hepatitis B surface antigen carriage, hepatitis B virus infection, obstetric population, rhesus blood group.
[11]. On the other hand, the Rh D-negative phenotype is found in 0.63% in China [8] and 0.68% in Hong Kong [9], as compared with 17.0% in the United Kingdom [10] and 15.0% in the United States [11]. While providing a selective advantage against severe malaria, the group-O phenotype increases the severity of cholera infection and susceptibility to gastrointestinal infection by E. coli O157 and H pylori (O Le group) [12]. For viral infections, secretors of the ABH and Le antigens have greater susceptibility to influenza viruses, rhinoviruses, respiratory syncytial virus and echoviruses [12], but the relationship with HBV infection remains inconclusive [13–24]. As for the Rh phenotypes, which reflect genetic drift and migration [12], no association with serum hepatitis was found [14,18,20,22,23], although in volunteer blood donors, Rh D positivity was significantly higher among HBV carriers [15]. In Hong Kong, routine antenatal screening for maternal ABO and Rh blood group phenotypes and HBsAg status is performed. To clarify the relationship between ABO and Rh blood group phenotypes with HBsAg carriage, we performed a retrospective study on all pregnant women who attended our antenatal clinic from 1998 to 2011. © 2013 John Wiley & Sons Ltd
Hepatitis B influenced by blood groups
MATERIALS AND METHODS Our hospital is a university teaching hospital with an annual delivery rate of ≥6000, and obstetric management is according to established practice and protocols. The results of routine antenatal screening of ABO and Rh blood groups and HBsAg status are entered in the medical records. All the clinical data, including the ICD-coded diagnoses and procedures, are captured in a computerized database set up by the local hospital authority using a standardized template. Data entry is made by trained midwives and obstetricians and double checked after delivery. This database has been validated previously [5]. For this retrospective cohort study approved by the Institutional Review Board, we retrieved data on maternal characteristics, HBsAg status, and ABO and Rh blood groups for all the pregnant women booked for confinement, irrespective of the number of foetuses or the outcome of pregnancy, between January 1998 and December 2011. The incidence of HBsAg carriage was analysed by blood group. The effects of advanced maternal age (≥35 years) and parity status (nulliparous or multiparous), as well as year of birth before or following the availability of the HBV vaccine (1984), and factors shown previously to have influenced the HBV carriage rate [5,25], were also examined. Each phenotype of the ABO blood group was examined individually, then all the non-O groups were combined for comparison with group-O, and further analysis was stratified by Rh D status. Student’s t-test and chisquared test with the calculated odds ratio (OR) and 95% confidence intervals (CI) were used for analysis. A P-value of
doi:10.1111/jvh.12219
Maternal ABO and rhesus blood group phenotypes and hepatitis B surface antigen carriage T. T. Lao, D. S. Sahota, M.-K. Chung, T. K. W. Cheung, Y. K. Y. Cheng and T. Y. Leung Department of Obstetrics & Gynaecology, The Chinese University of Hong Kong, Prince of Wales Hospital, Shatin, Hong Kong, China Received July 2013; accepted for publication September 2013
SUMMARY. In view of a persistently high prevalence of hepatitis B surface antigen (HBsAg) carriage in our obstetric population, we examined the association between HBsAg carriage with maternal ABO and rhesus (Rh) blood group phenotypes determined at routine antenatal screening. In a retrospective study, the antenatal screening results of women booked for confinement between 1998 and 2011 in our hospital were examined for the relationship between HBsAg carriage with the ABO and rhesus blood groups, taking into account also the effects of advanced maternal age (≥35 years) and parity status (nulliparous or multiparous), and year of birth before or following the availability of the hepatitis B vaccine (1984). HBsAg carriage was found in 9.9%, 9.6%, 9.1% and 10.2% (P = 0.037) for group-A (n = 20 581 or 26.1%), -B (n = 20 744 or 26.4%), -AB (n = 5138 or 6.5%) and -O (n = 32 242 or 41.0%) among the 78 705 women in the study cohort.
INTRODUCTION The prevalence of chronic hepatitis B virus (HBV) infection is much higher in the Asian and Chinese populations, being 20% or more even among the immigrants to western countries [1–3]. In Hong Kong, the maternal carriage rate for hepatitis B surface antigen (HBsAg) remains around 10% [4,5], despite the introduction of the hepatitis B vaccine in the 1980s [6,7]. We suspect that this could be related to phenotypic differences among different populations, such as the different frequency of the ABO and Rhesus (Rh) blood groups. In China and Hong Kong, the group-O phenotype of the ABO blood type is found in 50.0% [8] and 41.83% [9], respectively, compared with 44.0% in both the United Kingdom [10] and United States Abbreviation: AA, Australian antigen; HBsAg, hepatitis B surface antigen; HBV, hepatitis B virus; HCC, hepatocellular carcinoma; HCV, hepatitis C virus. Correspondence: Prof. Terence T. Lao, MD, Department of Obstetrics & Gynaecology, Prince of Wales Hospital, Shatin, Hong Kong SAR, China. E-mail: [email protected]
Rhesus negativity was found in 0.6%, and HBsAg carriage was 12.3% and 9.8%, respectively, for the Rh-negative and Rh-positive women (P = 0.071). Carriage rate between group-O and non-O was influenced by nulliparity, age ≥35 years and Rh-positive status. Regression analysis indicated that group-B (P = 0.044, aOR = 1.062, 95% CI 1.002–1.127) and group-AB (P = 0.016, aOR = 1.134, 95% CI 1.024–1.256) were associated with HBsAg carriage. Blood groups-B and -AB are associated with increased hepatitis B virus (HBV) infection in our population, and further studies are warranted to elucidate the implications of this on the sequelae of HBV infection. Keywords: ABO blood group, Chinese, hepatitis B surface antigen carriage, hepatitis B virus infection, obstetric population, rhesus blood group.
[11]. On the other hand, the Rh D-negative phenotype is found in 0.63% in China [8] and 0.68% in Hong Kong [9], as compared with 17.0% in the United Kingdom [10] and 15.0% in the United States [11]. While providing a selective advantage against severe malaria, the group-O phenotype increases the severity of cholera infection and susceptibility to gastrointestinal infection by E. coli O157 and H pylori (O Le group) [12]. For viral infections, secretors of the ABH and Le antigens have greater susceptibility to influenza viruses, rhinoviruses, respiratory syncytial virus and echoviruses [12], but the relationship with HBV infection remains inconclusive [13–24]. As for the Rh phenotypes, which reflect genetic drift and migration [12], no association with serum hepatitis was found [14,18,20,22,23], although in volunteer blood donors, Rh D positivity was significantly higher among HBV carriers [15]. In Hong Kong, routine antenatal screening for maternal ABO and Rh blood group phenotypes and HBsAg status is performed. To clarify the relationship between ABO and Rh blood group phenotypes with HBsAg carriage, we performed a retrospective study on all pregnant women who attended our antenatal clinic from 1998 to 2011. © 2013 John Wiley & Sons Ltd
Hepatitis B influenced by blood groups
MATERIALS AND METHODS Our hospital is a university teaching hospital with an annual delivery rate of ≥6000, and obstetric management is according to established practice and protocols. The results of routine antenatal screening of ABO and Rh blood groups and HBsAg status are entered in the medical records. All the clinical data, including the ICD-coded diagnoses and procedures, are captured in a computerized database set up by the local hospital authority using a standardized template. Data entry is made by trained midwives and obstetricians and double checked after delivery. This database has been validated previously [5]. For this retrospective cohort study approved by the Institutional Review Board, we retrieved data on maternal characteristics, HBsAg status, and ABO and Rh blood groups for all the pregnant women booked for confinement, irrespective of the number of foetuses or the outcome of pregnancy, between January 1998 and December 2011. The incidence of HBsAg carriage was analysed by blood group. The effects of advanced maternal age (≥35 years) and parity status (nulliparous or multiparous), as well as year of birth before or following the availability of the HBV vaccine (1984), and factors shown previously to have influenced the HBV carriage rate [5,25], were also examined. Each phenotype of the ABO blood group was examined individually, then all the non-O groups were combined for comparison with group-O, and further analysis was stratified by Rh D status. Student’s t-test and chisquared test with the calculated odds ratio (OR) and 95% confidence intervals (CI) were used for analysis. A P-value of
