- Email: [email protected]
The “ABO Cross-transplantation Problem” in Liver Transplantation in Korea
The “ABO Cross-transplantation Problem” in Liver Transplantation in Korea M.S. Park, K.W. Lee, T. You, S.W. Suh, H. Kim, Y. Choi, G. Hong, O.K. Kim, N.J. Yi, and K.S. Suh ABSTRACT ABO blood group matching policy between donor and recipients is a chief element of organ allocation. However, O blood group donors may donate to all other blood group recipients, and ABO cross-transplantation has led to excessively long delays for blood group O. To investigate the consequence of this problem, we analyzed the recipients/donor rates according to ABO blood groups and cross-transplantation rates among them. Data about deceased donors and liver transplants performed in Korea from January 2008 to September 2012 were reviewed. The proportion of recipient to donor in the O blood group was lower compared to non-O groups (0.61). The percentage of O blood group transplantations in the Korean Network for Organ Sharing (KONOS) status 2B was lower than non-O groups (13.6%). In the status 1 and 2A groups, 44.4% of O blood group donors were allocated to non-O transplantations. Also, 30.7% O blood group donors were allocated to non-O transplantations in the status 2B groups. In conclusion, the ABO crosstransplantation in blood group O donors has led to lower transplantation rates of blood group O in status 1, 2A, and especially, the 2B group. Therefore, the KONOS allocation system should be re-evaluated to address this problem.
B
ECAUSE of the shortage of deceased donors, livers must be allocated in a fair and transparent way to patients on the waiting list. ABO blood group matching policy between donor and recipients is a key element of organ allocation. However, unequal distribution of the ABO blood groups in the population can lead to inequality in the distribution of organs. Also, O blood group donors may donate to all other blood group recipients and A, B, and O blood group donors may donate to the AB blood group recipients. The cross-transplantation of deceased donors may lead to different waiting times according to ABO blood group.1,2 In Korea, liver transplantation was allocated by the Korean Network for Organ Sharing (KONOS) status based on Child-Turcotte-Pugh score instead of the model for end-stage liver disease (MELD) system of UNOS (United Network for Organ Sharing). KONOS status was divided into 4 groups (1, 2A, 2B, 3) according to the severity of liver disease. KONOS status 1 or 2A designates an urgent condition. In the current allocation system, O blood group donors should be allocated to all blood groups in KONOS status I or 2A first, then allocated to all blood groups in status 2B.3 Finally, O blood recipients may have a lower chance of liver transplantation. Therefore, in the present study, we analyzed the transplant rates according
to ABO blood groups and cross-transplantation rates among them. PATIENTS AND METHODS We analyzed the data concerning deceased donors and liver transplantations performed in Korea from January 2008 to Table 1. Recipient and Donor Rates According to ABO Blood Group and Number of Recipients in Relation to Status Condition Deceased Recipients by Recipient/ Status 1&2A Blood Donors by ABO ABO Recipients Donor (Urgency Group Donor Group (%) Group (%) Rates Patients) Status 2B
A B AB O
457 333 133 378
(35.1) (25.6) (10.2) (29.1)
479 376 217 229
(36.8) (28.9) (16.7) (17.6)
1.04 1.13 1.63 0.61
262 198 88 139
(38.2) 210 (36.2) (28.8) 171 (29.4) (12.8) 121 (20.8) (20.2) 79 (13.6)
From the Department of Surgery, Seoul National University College of Medicine, Seoul, Korea. Address reprint requests to Kwang-Woong Lee, Department of Surgery, Seoul National University College of Medicine, 28 Yongon-Dong, Chongno-gu, Seoul, 110-744, Korea. E-mail: [email protected]
0041-1345/13/$esee front matter http://dx.doi.org/10.1016/j.transproceed.2013.08.046
ª 2013 by Elsevier Inc. All rights reserved. 360 Park Avenue South, New York, NY 10010-1710
2878
Transplantation Proceedings, 45, 2878e2879 (2013)
ABO CROSS-TRANSPLANT PROBLEM
2879
Table 2. ABO Cross-transplantation Rates in Status 1 and 2A Groups
A B AB O
A
B
AB
211 (86.8%) 32 (13.2%)
151 (92.1) 13 (7.9)
30 (100%)
Donor Blood Type
Recipient Blood Type
Donor Blood Type
Recipient Blood Type
Table 3. ABO Cross-transplantation Rates in Status 2B Groups
O
51 47 13 139
(20.4%) (18.8%) (5.2%) (55.6%)
September 2012. Data were obtained by the KONOS. We divided liver transplantation procedures into two subgroups based on KONOS status (status 1 & 2A and status 2B).
RESULTS Recipient/Donor Rates According to ABO Blood Groups
The percentage of A, B, AB, and O blood group donors were 35.1%, 25.6%, 10.2%, and 29.1%, respectively. The proportion of transplant to donor in A, B, AB, and O blood groups were 1.04, 1.13, 1.63, and 0.61, respectively. The proportion of A, B, AB, and O blood group transplantations in status 2B were 36.2%, 29.4%, 20.8%, and 13.6%, respectively (Table 1). ABO Cross-transplantation Rates
In the status 1 and 2A group, the percentage of A, B, AB, and O blood group transplantations allocated O blood group donors were 20.4%, 18.8%, 5.2%, and 55.6%, respectively (Table 2). And the percentage of A, B, AB, and O blood group transplantations allocated O blood group donors were 9.6%, 16.7%, 4.4%, and 69.3%, respectively, in the status 2B group (Table 3). DISCUSSION
When we compared recipients/donor rates according to ABO blood groups, we observed lower transplantation rates of O blood group compared to the non-O blood group. In an analysis of ABO blood type distribution by country, blood type percentage in Korea is as follows: A blood group, 34%; B blood group, 27%; AB blood group, 11; and O blood group, 28%. In our study, the ABO distribution of deceased donors was similar with nationwide ABO distribution.4 The main reason for lower transplantation rates of O recipients is the cross-transplantation of the O blood group liver to non-O recipients. In the current KONOS system, O blood group donors first should be allocated all
A B AB O
A
B
AB
199 (96.1%) 8 (3.9%)
152 (93.8) 10 (6.2)
98 (100%)
O
11 19 5 79
(9.6%) (16.7%) (4.4%) (69.3%)
blood groups in status l or 2A. Some of their livers are also used for non-O recipients in status 2B this may lead to lower transplantation rates of blood group O recipients in status 2B, especially. In our study, 44.4% (111/250) O blood group donors were allocated to non-O recipients of the status l and 2A groups, and 30.7% (35/114) O blood group donors were also allocated to non-O recipients in the status 2B groups. To resolve this problem, a new allocation system that best suits our society is needed. If the O blood group donors were allocated to all blood groups transplantations of status 1 or 2A first, then allocated to only O blood groups of status 2B, the transplantation rate of blood group O in status 2B would increase. If 250 of all O blood group donors were allocated all blood group transplantations of status 1 or 2A first, then 128 O blood group donors would be allocated to only O blood group transplantations of status 2B in this study, and the transplantation rate of O blood group in status 2B would be 21.5%. In conclusion, the export of blood group O donor livers to the other blood groups leads to a lower transplantation rate of blood types O in status 2B, especially. Therefore, allocation of livers from O blood group deceased donors to recipients of other blood groups should be prevented as much as possible. REFERENCES 1. Avolio AW, Barone M. Use of “O” blood group liver donors for no identical recipients: does this represent a double penalty for “O” blood group candicates? Transplant Proc. 2006;38:1063. 2. de Meester J, Bogers M, de Winter H, et al. Which ABOmatching rule should be the decisive factor in the choice between a highly urgent and an elective patient? Transpl Int. 2002;15:431. 3. Korean Network for Organ Sharing (KONOS). An enforecement ordinance of law about organ or transplantation[Internet]. Seoul: KONOS; 2009. Accessed April 9, 2012. Available from: http://www.konos.go.kr. 4. Racial and Ethnic Distribution of ABO Blood Types BloodBook.com, Blood Information for Life. Accessed: November 2012.
B
ECAUSE of the shortage of deceased donors, livers must be allocated in a fair and transparent way to patients on the waiting list. ABO blood group matching policy between donor and recipients is a key element of organ allocation. However, unequal distribution of the ABO blood groups in the population can lead to inequality in the distribution of organs. Also, O blood group donors may donate to all other blood group recipients and A, B, and O blood group donors may donate to the AB blood group recipients. The cross-transplantation of deceased donors may lead to different waiting times according to ABO blood group.1,2 In Korea, liver transplantation was allocated by the Korean Network for Organ Sharing (KONOS) status based on Child-Turcotte-Pugh score instead of the model for end-stage liver disease (MELD) system of UNOS (United Network for Organ Sharing). KONOS status was divided into 4 groups (1, 2A, 2B, 3) according to the severity of liver disease. KONOS status 1 or 2A designates an urgent condition. In the current allocation system, O blood group donors should be allocated to all blood groups in KONOS status I or 2A first, then allocated to all blood groups in status 2B.3 Finally, O blood recipients may have a lower chance of liver transplantation. Therefore, in the present study, we analyzed the transplant rates according
to ABO blood groups and cross-transplantation rates among them. PATIENTS AND METHODS We analyzed the data concerning deceased donors and liver transplantations performed in Korea from January 2008 to Table 1. Recipient and Donor Rates According to ABO Blood Group and Number of Recipients in Relation to Status Condition Deceased Recipients by Recipient/ Status 1&2A Blood Donors by ABO ABO Recipients Donor (Urgency Group Donor Group (%) Group (%) Rates Patients) Status 2B
A B AB O
457 333 133 378
(35.1) (25.6) (10.2) (29.1)
479 376 217 229
(36.8) (28.9) (16.7) (17.6)
1.04 1.13 1.63 0.61
262 198 88 139
(38.2) 210 (36.2) (28.8) 171 (29.4) (12.8) 121 (20.8) (20.2) 79 (13.6)
From the Department of Surgery, Seoul National University College of Medicine, Seoul, Korea. Address reprint requests to Kwang-Woong Lee, Department of Surgery, Seoul National University College of Medicine, 28 Yongon-Dong, Chongno-gu, Seoul, 110-744, Korea. E-mail: [email protected]
0041-1345/13/$esee front matter http://dx.doi.org/10.1016/j.transproceed.2013.08.046
ª 2013 by Elsevier Inc. All rights reserved. 360 Park Avenue South, New York, NY 10010-1710
2878
Transplantation Proceedings, 45, 2878e2879 (2013)
ABO CROSS-TRANSPLANT PROBLEM
2879
Table 2. ABO Cross-transplantation Rates in Status 1 and 2A Groups
A B AB O
A
B
AB
211 (86.8%) 32 (13.2%)
151 (92.1) 13 (7.9)
30 (100%)
Donor Blood Type
Recipient Blood Type
Donor Blood Type
Recipient Blood Type
Table 3. ABO Cross-transplantation Rates in Status 2B Groups
O
51 47 13 139
(20.4%) (18.8%) (5.2%) (55.6%)
September 2012. Data were obtained by the KONOS. We divided liver transplantation procedures into two subgroups based on KONOS status (status 1 & 2A and status 2B).
RESULTS Recipient/Donor Rates According to ABO Blood Groups
The percentage of A, B, AB, and O blood group donors were 35.1%, 25.6%, 10.2%, and 29.1%, respectively. The proportion of transplant to donor in A, B, AB, and O blood groups were 1.04, 1.13, 1.63, and 0.61, respectively. The proportion of A, B, AB, and O blood group transplantations in status 2B were 36.2%, 29.4%, 20.8%, and 13.6%, respectively (Table 1). ABO Cross-transplantation Rates
In the status 1 and 2A group, the percentage of A, B, AB, and O blood group transplantations allocated O blood group donors were 20.4%, 18.8%, 5.2%, and 55.6%, respectively (Table 2). And the percentage of A, B, AB, and O blood group transplantations allocated O blood group donors were 9.6%, 16.7%, 4.4%, and 69.3%, respectively, in the status 2B group (Table 3). DISCUSSION
When we compared recipients/donor rates according to ABO blood groups, we observed lower transplantation rates of O blood group compared to the non-O blood group. In an analysis of ABO blood type distribution by country, blood type percentage in Korea is as follows: A blood group, 34%; B blood group, 27%; AB blood group, 11; and O blood group, 28%. In our study, the ABO distribution of deceased donors was similar with nationwide ABO distribution.4 The main reason for lower transplantation rates of O recipients is the cross-transplantation of the O blood group liver to non-O recipients. In the current KONOS system, O blood group donors first should be allocated all
A B AB O
A
B
AB
199 (96.1%) 8 (3.9%)
152 (93.8) 10 (6.2)
98 (100%)
O
11 19 5 79
(9.6%) (16.7%) (4.4%) (69.3%)
blood groups in status l or 2A. Some of their livers are also used for non-O recipients in status 2B this may lead to lower transplantation rates of blood group O recipients in status 2B, especially. In our study, 44.4% (111/250) O blood group donors were allocated to non-O recipients of the status l and 2A groups, and 30.7% (35/114) O blood group donors were also allocated to non-O recipients in the status 2B groups. To resolve this problem, a new allocation system that best suits our society is needed. If the O blood group donors were allocated to all blood groups transplantations of status 1 or 2A first, then allocated to only O blood groups of status 2B, the transplantation rate of blood group O in status 2B would increase. If 250 of all O blood group donors were allocated all blood group transplantations of status 1 or 2A first, then 128 O blood group donors would be allocated to only O blood group transplantations of status 2B in this study, and the transplantation rate of O blood group in status 2B would be 21.5%. In conclusion, the export of blood group O donor livers to the other blood groups leads to a lower transplantation rate of blood types O in status 2B, especially. Therefore, allocation of livers from O blood group deceased donors to recipients of other blood groups should be prevented as much as possible. REFERENCES 1. Avolio AW, Barone M. Use of “O” blood group liver donors for no identical recipients: does this represent a double penalty for “O” blood group candicates? Transplant Proc. 2006;38:1063. 2. de Meester J, Bogers M, de Winter H, et al. Which ABOmatching rule should be the decisive factor in the choice between a highly urgent and an elective patient? Transpl Int. 2002;15:431. 3. Korean Network for Organ Sharing (KONOS). An enforecement ordinance of law about organ or transplantation[Internet]. Seoul: KONOS; 2009. Accessed April 9, 2012. Available from: http://www.konos.go.kr. 4. Racial and Ethnic Distribution of ABO Blood Types BloodBook.com, Blood Information for Life. Accessed: November 2012.