Letters to the Editor
97
The Role of anti-HBc IgM Screening of Blood Donors Dear Editor, I read with interest the article ‘The Role of anti-HBc IgM Screening of Blood Donors’ [1]. Authors recommend screening of blood donors for antibody to hepatitis B core antigen (anti-HBc) IgM class in addition to hepatitis B surface antigen (HBsAg) for reduction of residual risk of transfusion transmitted hepatitis B virus (TT-HBV) infection. Traditionally ‘anti-HBc alone’ has been studied extensively in blood donors. ‘anti-HBc alone’ denotes presence of anti-HBc (total) in absence of HBsAg and anti-HBs (antibody to HBsAg). Studies from countries with moderate endemicity of HBV infection reported HBV-DNA in 20-67% of blood donors with ‘anti-HBc alone’ [2,3]. Rarely donors with antiHBc and anti-HBs were reported with HBV-DNA [3]. In contrast, authors are first to recommend anti-HBc IgM for screening of blood donors. Authors hypothesis is based on the fact that the anti-HBc IgM appears first thus making it suitable for screening. It is simplistic view of perplexing serological and virological events associated with HBV infections and clinical syndromes. Anti-HBc IgM is known to have major role in diagnosis of acute as compared to chronic HBV infection of carrier state including HBsAg (Hepatitis B e Antigen) negative HBV infections [4]. Anti HBc IgM also has limited utility to diagnosis of chronic HBV infections with mutant strains and such infections are not uncommon in our country [5]. Thus anti-HBc IgM screening will result in low yield in blood donors [6].
Table 1 Anti-HBs and anti-HBc IgM status in anti HBc (total) positive blood donors Anti-HBs positive
Anti HBs negative (i.e. anti-HBc alone)
Total
Anti-HBc IgM positive Anti-HBc IgM negative
6 (22.2%)
4
(19%)
1 0 (20.8%)
2 1 (77.8%)
17
(81%)
3 8 (79.2%)
Total
2 7 (100%)
21
(100%)
4 8 (100%)
χ2 (Yates Correction) = 0.008, df =1, p> 0.5, NS. DNA in blood donors for policy formulation. Till such time, it is recommended that ‘anti-Hbc alone’ positive blood units should be discarded. References 1. Kumar H, Gupta PK, Jaiprakash M. The role of anti-HBc IgM in screening of blood donors. MJAFI 2007; 63;350-2. 2. Chaudhari V, Nanu A, Panda SK, Chand P. Evaluation of serologic screening of blood donors in India reveals a lack of correlation between anti-HBc titer and PCR- amplified HBC DNA. Transfusion 2003; 43: 1142-8.
A study undertaken from January to June 2005 (unpublished data) contradicts hypothesis of IgM anti-HBc in blood screening. A total 476 voluntary blood donors were enrolled for the study. They were healthy male, free from infections as per current National Blood Transfusion guidelines. Donors were HBs Ag negative and did not give past history of jaundice (deferral rate of 2.1% and 1.9% respectively). They were screened for anti-HBc (total) by Enzyme Immune Assay (EIA) of which 48 (10.1%) tested positive. These 48 subjects were assayed for anti-HBs and anti-HBc IgM by EIA (Table 1). It was concluded that 4.4% (21/476) donors were ‘anti-HBc alone’. 2.1% (10/476) donors were anti-HBc IgM positive and they represented only 19.0% (4/21) of ‘anti-HBc alone’ donors. Thus 81% (17/21) of potentially infectious ‘anti-Hbc alone’ donors would have been overlooked with anti-HBc IgM assay.
3. Behzad-Behbahani A, Mafi-Nejad A, Tabei SZ, Lankarani KB,Torab A, Moaddeb A. Anti-HBc & HBV-DNA detection in blood donors negative for hepatitis virus surface antigen in reducing risk of transfusion associated HBV infection. Indian J Med Res 2000; 123: 37-42.
Of course, there is unanimity in necessity for additional screening of blood donors in reducing residual risk of TT-HBV. However, anti-HBc IgM in blood donor screening may not be beneficial. In this background, it will be prudent to undertake a multi-centric study correlating anti-HBc (total and IgM), anti-HBs and HBV-
6. AC Anand, P Puri. Hepatitis B Virus Infection: Emerging challenges for the Armed Forces. MJAFI 2007; 63: 312-4.
4. Roggendorf M, Deinhardt F, Frosner G, Scheid R, Bayerl B, Zachoval R. Immunoglobulin M Antibodies to Hepatitis B Core Antigen: Evaluation of Enzyme Immunoassay for Diagnosis of Hepatitis B Virus Infection. J Clin Microbiol 1981; 13:4618-26. 5. Vivekanandan P, Abraham P, Sridharan G, et al. High frequency of the 1896 precore mutation in patients and blood donors with hepatitis B virus infection form the Indian subcontinent. Mol Diagn 2004; 8: 51-6.
Surg Cdr CN Chaudhari* *Classified Specialist (Microbiology), INHS Jeevanti, Vasco-daGama-403802.
Reply Dear Editor, Thanks for the interest generated in the article published in MJAFI. The aim of the study was to screen blood donors for antiHBc IgM for detection of HBV infection in the window period of infection when the donor may be HBsAg negative. In blood donors we are more interested in acute HBV infection than the carrier state, which can be easily detected by screening blood donors for HBsAg and anti-HBc IgM. In early cases of infection where the individual may be negative for these markers, then nucleic acid technology (NAT) for screening for HBV DNA can be useful. In our study, we have highlighted the limitations of screening
MJAFI, Vol. 64, No. 1, 2008
the donors for anti-HBc (total), as the positivity rate varies from 17 - 29%, whereas, the positivity rate for anti-HBc IgM is only 0.39% in HBsAg negative donors. Screening of blood for anti-HBc total is practical in the western countries as the incidence of HBsAg and anti-HBc is low in these countries. Whereas, in our country the incidence of HBsAg is high. It is therefore recommended that all blood units should be tested for anti-HBc IgM alongwith HBsAg to check the infectivity status of blood donors in the window period. Col H Kumar Professor & Head (Department of Transfusion Medicine), Armed Forces Medical College, Pune.
97
The Role of anti-HBc IgM Screening of Blood Donors Dear Editor, I read with interest the article ‘The Role of anti-HBc IgM Screening of Blood Donors’ [1]. Authors recommend screening of blood donors for antibody to hepatitis B core antigen (anti-HBc) IgM class in addition to hepatitis B surface antigen (HBsAg) for reduction of residual risk of transfusion transmitted hepatitis B virus (TT-HBV) infection. Traditionally ‘anti-HBc alone’ has been studied extensively in blood donors. ‘anti-HBc alone’ denotes presence of anti-HBc (total) in absence of HBsAg and anti-HBs (antibody to HBsAg). Studies from countries with moderate endemicity of HBV infection reported HBV-DNA in 20-67% of blood donors with ‘anti-HBc alone’ [2,3]. Rarely donors with antiHBc and anti-HBs were reported with HBV-DNA [3]. In contrast, authors are first to recommend anti-HBc IgM for screening of blood donors. Authors hypothesis is based on the fact that the anti-HBc IgM appears first thus making it suitable for screening. It is simplistic view of perplexing serological and virological events associated with HBV infections and clinical syndromes. Anti-HBc IgM is known to have major role in diagnosis of acute as compared to chronic HBV infection of carrier state including HBsAg (Hepatitis B e Antigen) negative HBV infections [4]. Anti HBc IgM also has limited utility to diagnosis of chronic HBV infections with mutant strains and such infections are not uncommon in our country [5]. Thus anti-HBc IgM screening will result in low yield in blood donors [6].
Table 1 Anti-HBs and anti-HBc IgM status in anti HBc (total) positive blood donors Anti-HBs positive
Anti HBs negative (i.e. anti-HBc alone)
Total
Anti-HBc IgM positive Anti-HBc IgM negative
6 (22.2%)
4
(19%)
1 0 (20.8%)
2 1 (77.8%)
17
(81%)
3 8 (79.2%)
Total
2 7 (100%)
21
(100%)
4 8 (100%)
χ2 (Yates Correction) = 0.008, df =1, p> 0.5, NS. DNA in blood donors for policy formulation. Till such time, it is recommended that ‘anti-Hbc alone’ positive blood units should be discarded. References 1. Kumar H, Gupta PK, Jaiprakash M. The role of anti-HBc IgM in screening of blood donors. MJAFI 2007; 63;350-2. 2. Chaudhari V, Nanu A, Panda SK, Chand P. Evaluation of serologic screening of blood donors in India reveals a lack of correlation between anti-HBc titer and PCR- amplified HBC DNA. Transfusion 2003; 43: 1142-8.
A study undertaken from January to June 2005 (unpublished data) contradicts hypothesis of IgM anti-HBc in blood screening. A total 476 voluntary blood donors were enrolled for the study. They were healthy male, free from infections as per current National Blood Transfusion guidelines. Donors were HBs Ag negative and did not give past history of jaundice (deferral rate of 2.1% and 1.9% respectively). They were screened for anti-HBc (total) by Enzyme Immune Assay (EIA) of which 48 (10.1%) tested positive. These 48 subjects were assayed for anti-HBs and anti-HBc IgM by EIA (Table 1). It was concluded that 4.4% (21/476) donors were ‘anti-HBc alone’. 2.1% (10/476) donors were anti-HBc IgM positive and they represented only 19.0% (4/21) of ‘anti-HBc alone’ donors. Thus 81% (17/21) of potentially infectious ‘anti-Hbc alone’ donors would have been overlooked with anti-HBc IgM assay.
3. Behzad-Behbahani A, Mafi-Nejad A, Tabei SZ, Lankarani KB,Torab A, Moaddeb A. Anti-HBc & HBV-DNA detection in blood donors negative for hepatitis virus surface antigen in reducing risk of transfusion associated HBV infection. Indian J Med Res 2000; 123: 37-42.
Of course, there is unanimity in necessity for additional screening of blood donors in reducing residual risk of TT-HBV. However, anti-HBc IgM in blood donor screening may not be beneficial. In this background, it will be prudent to undertake a multi-centric study correlating anti-HBc (total and IgM), anti-HBs and HBV-
6. AC Anand, P Puri. Hepatitis B Virus Infection: Emerging challenges for the Armed Forces. MJAFI 2007; 63: 312-4.
4. Roggendorf M, Deinhardt F, Frosner G, Scheid R, Bayerl B, Zachoval R. Immunoglobulin M Antibodies to Hepatitis B Core Antigen: Evaluation of Enzyme Immunoassay for Diagnosis of Hepatitis B Virus Infection. J Clin Microbiol 1981; 13:4618-26. 5. Vivekanandan P, Abraham P, Sridharan G, et al. High frequency of the 1896 precore mutation in patients and blood donors with hepatitis B virus infection form the Indian subcontinent. Mol Diagn 2004; 8: 51-6.
Surg Cdr CN Chaudhari* *Classified Specialist (Microbiology), INHS Jeevanti, Vasco-daGama-403802.
Reply Dear Editor, Thanks for the interest generated in the article published in MJAFI. The aim of the study was to screen blood donors for antiHBc IgM for detection of HBV infection in the window period of infection when the donor may be HBsAg negative. In blood donors we are more interested in acute HBV infection than the carrier state, which can be easily detected by screening blood donors for HBsAg and anti-HBc IgM. In early cases of infection where the individual may be negative for these markers, then nucleic acid technology (NAT) for screening for HBV DNA can be useful. In our study, we have highlighted the limitations of screening
MJAFI, Vol. 64, No. 1, 2008
the donors for anti-HBc (total), as the positivity rate varies from 17 - 29%, whereas, the positivity rate for anti-HBc IgM is only 0.39% in HBsAg negative donors. Screening of blood for anti-HBc total is practical in the western countries as the incidence of HBsAg and anti-HBc is low in these countries. Whereas, in our country the incidence of HBsAg is high. It is therefore recommended that all blood units should be tested for anti-HBc IgM alongwith HBsAg to check the infectivity status of blood donors in the window period. Col H Kumar Professor & Head (Department of Transfusion Medicine), Armed Forces Medical College, Pune.
