Molecular Investigation of Human Immunodeficiency Virus Type 2 Subtype A Cases in South Korea
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微生物临床杂志 2006年第4期
Center for AIDS Research, Department of Virology, National Institute of Health, #194, TongIl-Lo, Eunpyung-Gu, Seoul 122-701, Korea
ABSTRACT
We investigated the molecular characteristics of human immunodeficiency virus type 2 (HIV-2) subtype A isolates to clarify the transmission mode of HIV-2 within Korea. These findings indicated that the viruses from the six patients infected within Korea formed a distinct subcluster in the phylogenetic tree and might have been transmitted from one source.
TEXT
Human immunodeficiency virus type 2 (HIV-2) infection is restricted primarily to West Africa, Brazil, and Portugal (14). In Asia, 95% of the reported HIV-2 cases came from India (7, 13). Molecular epidemiology studies have led to classification of HIV-2 into eight specific subtypes, subtypes A to H (5). Molecular epidemiological analysis of nucleotide sequence data has been used in several investigations of HIV-1 transmission (1, 2, 10, 11, 12). Although the rate of sexual transmission of HIV-2 is very low relative to that of HIV-1, HIV-2 appears to be transmitted by the same routes as HIV-1 (6). Molecular evidence of homosexual transmission of HIV-2 in Spain has been reported (4).
In addition to the five HIV-2-infected individuals reported in our previous paper (8), five new HIV-2-infected people were identified from 2000 to 2002. Four of these additional five HIV-2-infected individuals were women between 19 and 21 years of age and were infected within Korea (Table 1). Of interest was that 9 of the 10 HIV-2-infected individuals resided in the southern part of Korea (the "SP" region), and domestic transmission was accounting for a large portion of the cases of HIV-2 transmission in Korea. Therefore, we conducted molecular epidemiological research on the HIV-2 isolates to find why HIV-2 infection was located in a specific region, to analyze the scale of HIV-2 infection, and to determine the future transmission trend for Korea.
This retrospective study was conducted with 10 HIV-2-infected individuals who had shown specific HIV-2 antibody reactivity by Western blot and particle agglutination assays from 1991 to 2004. According to Korea's monitoring policy for HIV-infected and AIDS patients, we measured CD4 and CD8 lymphocyte numbers every 6 months to monitor disease progression. We collected data on the epidemiological and clinical aspects of HIV-infected and AIDS patients, such as demographic characteristics and transmission routes (Table 1).
Of the 10 HIV-2-infected Koreans, the C2 to C5 region of HIV-2 env gene was analyzed for 9 of them. We conducted sequence analysis of two or three clones from them, as in the previous study (8). As shown in Fig. 1, based on the env gene alignment, isolates from eight patients clustered within the known subtype A. However, isolate KRC2080 belonged to subtype B. The patient with subtype B had engaged in unprotected heterosexual contact with prostitutes in Congo, which led to the introduction of the HIV-2 subtype B isolates into Korea. Interestingly, the earliest identified HIV-2-infected individual (subject KRB7051), a coresident of subject KRB7051 (subject KRB8091), and four female cases (subjects KRC0047, KRC0115, KRC2044, and KRC2235) formed a cluster whose sequences were distinguishable from the foreign reference sequences (bootstrap value = 100) (Fig. 1).
We randomly selected one clone sequence from each patient and analyzed the genetic diversity, divergence, and similarity. The interpatient sequence variability of the "SP" subcluster was 3.8 ± 1.0, an extremely low variability between sequences compared with the variability within the eight domestic Korean isolates (8.4 ± 5.4), African isolates (14.1 ± 2.8), and European isolates (12.8 ± 2.4) (Table 2). Furthermore, the divergence of the C2 to C5 region sequences between Korean and African isolates was lower than that between Korean and European isolates. This indicates that the nucleotide sequences of HIV-2 subtype A circulating in Korea are close to those of the African strain used in the reference sequences. These results are consistent with the epidemiological histories of the HIV-2-infected patients.
In addition, we investigated each patient's similarity with subject KRB7051, the earliest diagnosed patient in the "SP" subcluster (Table 3). The similarity of the sequence of the isolate from subject KRB7051 to that of the isolate from subject KRB8091 was 97.7%, followed by that to the isolate from subject KRC0047 with 97.0%, that to the isolate from subject KRC2044 with 96.8%, that to the isolate from subject KRC0115 with 96.3%, and that to the isolate from subject KRC2235 with 95.3%. The similarities of the sequence of the isolate from subject KRB7051 to those of the isolates from subjects KRB4063 and KRB4075, which were not in the "SP" subcluster, were 86.4% and 86.9%, respectively. Among the four female cases in the "SP" subcluster, two had had multiple sexual partners, and the other two recorded that they had had multiple contacts with an unidentified male.
HIV-2 infection is mostly confined to West Africa and is rarely discovered in Asia, except in India (7). In Korea, HIV-2 infection was first detected in the early 1990s in a seafarer infected overseas and his wife (8); however, cases of domestic infection have been identified since 2002. In particular, two infected females were in a potentially high-risk group for heterosexual transmission, which indicated a need for research on HIV-2 transmission routes in Korea.
Subject KRB7051 was the earliest patient in the "SP" subcluster detected and was followed up five times since being identified in 1997. His CD4 count stayed at less than 200 cells/μl, and he died of AIDS in 1999. We could not find any information on subject KRB8091. Four infected women were followed up for about 24 to 48 months and kept relatively high CD4 counts of more than 500 cells/μl, with no reports of specific opportunistic infections. Subject KRC2080, who was infected with subtype B, was detected in 2002 and was reported by a Japanese team (9). Extensive investigation of his history showed that he had experienced sexual contacts with prostitutes in Africa (1980 to 1984), Korea, and Japan (1989 to 2002). He also had a history of tuberculosis, and despite treatment with antiretroviral drugs, his CD4 counts gradually decreased to less than 250 cells/μl.
The genetic diversity of the HIV-2 isolates in the eight patients infected with subtype A was 8.4%, which is consistent with the values of 11.0 to 29.0% reported in other countries (3) and 12.8 to 14.1% in the reference sequences. The genetic diversity of the isolates from the six patients belonging to the "SP" subcluster was 3.8%, which is extremely low compared with the genetic diversity of 5.6% in a homosexual group in Spain (4). Furthermore, the V3 region genetic diversity in our Korean "SP" subcluster was 4.1%, which is lower than the interpatient variability range of 8.2 to 14.0% for unrelated viruses (15).
These results indicate that the viruses from the six patients infected inside Korea were closely related and might have been transmitted from one source. Although it was not revealed in the epidemiological investigation, there was suspicion of homosexual activity between two male patients (subjects KRB7051 and KRB8091) who once shared the same residence. HIV-2 infection and transmission inside Korea are rare and are restricted to specific areas.
ACKNOWLEDGMENTS
This project was supported by an intramural fund from the National Institute of Health of Korea.
REFERENCES
Birch, C. J., R. F. McCaw, D. M. Bulach, P. A. Revill, J. T. Carter, J. Tomnay, B. Hatch, T. V. Middleton, D. Chibo, M. G. Catton, J. L. Pankhurst, A. M. Breschkin, S. A. Locarnini, and D. S. Bowden. 2000. Molecular analysis of human immunodeficiency virus strains associated with a case of criminal transmission of the virus. J. Infect. Dis. 182:941-944.
Blanchard, A., S. Ferris, S. Chamaret, D. Guetard, and L. Montagnier. 1998. Molecular evidence for nosocomial transmission of human immunodeficiency virus from a surgeon to one of his patients. J. Virol. 72:4537-4540.
Breuer, J., N. W. Douglas, N. Goldman, and R. S. Daniels. 1995. Human immunodeficiency virus type 2 (HIV-2) env gene analysis: prediction of glycoprotein epitopes important for heterotypic neutralization and evidence for three genotype clusters within the HIV-2a subtype. J. Gen. Virol. 76:333-345.
Cilla, G., B. Rodes, E. Perez-Trallero, J. Arrizabalaga, and V. Soriano. 2001. Molecular evidence of homosexual transmission of HIV type 2 in Spain. AIDS Res. Hum. Retrovir. 17:417-422.
Damond, F., M. Worobey, P. Campa, I. Farfara, G. Colin, S. Matheron, F. Brun-Vezinet, D. L. Robertson, and F. Simon. 2004. Identification of a highly divergent HIV type 2 and proposal for a change in HIV type 2 classification. AIDS Res. Hum. Retrovir. 20:666-672.
Kanki, P. J., K. U. Travers, S. Mboup, C. C. Hsieh, R. G. Marlink, A. Gueye-Ndiaye, T. Siby, I. Thior, M. Hernandez-Avila, J. L. Sankale, I. Ndoye, and M. E. Essex. 1994. Slower heterosexual spread of HIV-2 than HIV-1. Lancet 343:943-946.
Kannangai, R., S. Ramalingam, K. J. Prakash, O. C. Abraham, R. George, R. C. Castillo, D. H. Schwartz, M. V. Jesudason, and G. Sridharan. 2000. Molecular confirmation of human immunodeficiency virus (HIV) type 2 in HIV-seropositive subjects in south India. Clin. Diagn. Lab. Immunol. 7:987-989.
Kim, S. S., E. Y. Kim, K. Y. Park, S. D. Suh, H. K. Park, Y. O. Shin, M. Bae, and J. S. Lee. 2000. Introduction of human immunodeficiency virus 2 infection into South Korea. Acta Virol. 44:15-22.
Kusagawa, S., Y. Imamura, A. Yasuoka, H. Hoshino, S. Oka, and Y. Takebe. 2003. Identification of HIV type 2 subtype B transmission in East Africa. AIDS Res. Hum. Retrovir. 19:1045-1049.
Machuca, R., L. B. Jorgensen, P. Theilade, and C. Nielsen. 2001. Molecular investigation of transmission of human immunodeficiency virus type 1 in a criminal case. Clin. Diagn. Lab. Immunol. 8:884-890.
Metzker, M. L., D. P. Mindell, X. M. Liu, R. G. Ptak, R. A. Gibbs, and D. M. Hillis. 2002. Molecular evidence of HIV-1 transmission in a criminal case. Proc. Natl. Acad. Sci. USA 99:14292-14297.
Ou, C. Y., C. A. Ciesielski, G. Myers, C. I. Bandea, C. C. Luo, B. T. Korber, J. I. Mullins, G. Schochetman, R. L. Berkelman, A. N. Economou, J. J. Witte, L. J. Furman, G. A. Satten, K. A. MacInnes, J. W. Curran, and H. W. Jaffe. 1992. Molecular epidemiology of HIV transmission in a dental practice. Science 256:1165-1171.
Pfutzner, A., U. Dietrich, U. von Eichel, H. von Briesen, H. D. Brede, J. K. Maniar, and H. Rubsamen-Waigmann. 1992. HIV-1 and HIV-2 infections in a high-risk population in Bombay, India: evidence for the spread of HIV-2 and presence of a divergent HIV-1 subtype. J. Acquir. Immune Defic. Syndr. 5:972-977.
Reeves, J. D., and R. W. Doms. 2002. Human immunodeficiency virus type 2. J. Gen. Virol. 83:1253-1265.
Sankale, J. L., R. S. de la Tour, B. Renjifo, T. Siby, S. Mboup, R. G. Marlink, M. E. Essex, and P. J. Kanki. 1995. Intrapatient variability of the human immunodeficiency virus type 2 envelope V3 loop. AIDS Res. Hum. Retrovir. 11:617-623.(Jeong-Gu Nam, Gab Jung Ki)
ABSTRACT
We investigated the molecular characteristics of human immunodeficiency virus type 2 (HIV-2) subtype A isolates to clarify the transmission mode of HIV-2 within Korea. These findings indicated that the viruses from the six patients infected within Korea formed a distinct subcluster in the phylogenetic tree and might have been transmitted from one source.
TEXT
Human immunodeficiency virus type 2 (HIV-2) infection is restricted primarily to West Africa, Brazil, and Portugal (14). In Asia, 95% of the reported HIV-2 cases came from India (7, 13). Molecular epidemiology studies have led to classification of HIV-2 into eight specific subtypes, subtypes A to H (5). Molecular epidemiological analysis of nucleotide sequence data has been used in several investigations of HIV-1 transmission (1, 2, 10, 11, 12). Although the rate of sexual transmission of HIV-2 is very low relative to that of HIV-1, HIV-2 appears to be transmitted by the same routes as HIV-1 (6). Molecular evidence of homosexual transmission of HIV-2 in Spain has been reported (4).
In addition to the five HIV-2-infected individuals reported in our previous paper (8), five new HIV-2-infected people were identified from 2000 to 2002. Four of these additional five HIV-2-infected individuals were women between 19 and 21 years of age and were infected within Korea (Table 1). Of interest was that 9 of the 10 HIV-2-infected individuals resided in the southern part of Korea (the "SP" region), and domestic transmission was accounting for a large portion of the cases of HIV-2 transmission in Korea. Therefore, we conducted molecular epidemiological research on the HIV-2 isolates to find why HIV-2 infection was located in a specific region, to analyze the scale of HIV-2 infection, and to determine the future transmission trend for Korea.
This retrospective study was conducted with 10 HIV-2-infected individuals who had shown specific HIV-2 antibody reactivity by Western blot and particle agglutination assays from 1991 to 2004. According to Korea's monitoring policy for HIV-infected and AIDS patients, we measured CD4 and CD8 lymphocyte numbers every 6 months to monitor disease progression. We collected data on the epidemiological and clinical aspects of HIV-infected and AIDS patients, such as demographic characteristics and transmission routes (Table 1).
Of the 10 HIV-2-infected Koreans, the C2 to C5 region of HIV-2 env gene was analyzed for 9 of them. We conducted sequence analysis of two or three clones from them, as in the previous study (8). As shown in Fig. 1, based on the env gene alignment, isolates from eight patients clustered within the known subtype A. However, isolate KRC2080 belonged to subtype B. The patient with subtype B had engaged in unprotected heterosexual contact with prostitutes in Congo, which led to the introduction of the HIV-2 subtype B isolates into Korea. Interestingly, the earliest identified HIV-2-infected individual (subject KRB7051), a coresident of subject KRB7051 (subject KRB8091), and four female cases (subjects KRC0047, KRC0115, KRC2044, and KRC2235) formed a cluster whose sequences were distinguishable from the foreign reference sequences (bootstrap value = 100) (Fig. 1).
We randomly selected one clone sequence from each patient and analyzed the genetic diversity, divergence, and similarity. The interpatient sequence variability of the "SP" subcluster was 3.8 ± 1.0, an extremely low variability between sequences compared with the variability within the eight domestic Korean isolates (8.4 ± 5.4), African isolates (14.1 ± 2.8), and European isolates (12.8 ± 2.4) (Table 2). Furthermore, the divergence of the C2 to C5 region sequences between Korean and African isolates was lower than that between Korean and European isolates. This indicates that the nucleotide sequences of HIV-2 subtype A circulating in Korea are close to those of the African strain used in the reference sequences. These results are consistent with the epidemiological histories of the HIV-2-infected patients.
In addition, we investigated each patient's similarity with subject KRB7051, the earliest diagnosed patient in the "SP" subcluster (Table 3). The similarity of the sequence of the isolate from subject KRB7051 to that of the isolate from subject KRB8091 was 97.7%, followed by that to the isolate from subject KRC0047 with 97.0%, that to the isolate from subject KRC2044 with 96.8%, that to the isolate from subject KRC0115 with 96.3%, and that to the isolate from subject KRC2235 with 95.3%. The similarities of the sequence of the isolate from subject KRB7051 to those of the isolates from subjects KRB4063 and KRB4075, which were not in the "SP" subcluster, were 86.4% and 86.9%, respectively. Among the four female cases in the "SP" subcluster, two had had multiple sexual partners, and the other two recorded that they had had multiple contacts with an unidentified male.
HIV-2 infection is mostly confined to West Africa and is rarely discovered in Asia, except in India (7). In Korea, HIV-2 infection was first detected in the early 1990s in a seafarer infected overseas and his wife (8); however, cases of domestic infection have been identified since 2002. In particular, two infected females were in a potentially high-risk group for heterosexual transmission, which indicated a need for research on HIV-2 transmission routes in Korea.
Subject KRB7051 was the earliest patient in the "SP" subcluster detected and was followed up five times since being identified in 1997. His CD4 count stayed at less than 200 cells/μl, and he died of AIDS in 1999. We could not find any information on subject KRB8091. Four infected women were followed up for about 24 to 48 months and kept relatively high CD4 counts of more than 500 cells/μl, with no reports of specific opportunistic infections. Subject KRC2080, who was infected with subtype B, was detected in 2002 and was reported by a Japanese team (9). Extensive investigation of his history showed that he had experienced sexual contacts with prostitutes in Africa (1980 to 1984), Korea, and Japan (1989 to 2002). He also had a history of tuberculosis, and despite treatment with antiretroviral drugs, his CD4 counts gradually decreased to less than 250 cells/μl.
The genetic diversity of the HIV-2 isolates in the eight patients infected with subtype A was 8.4%, which is consistent with the values of 11.0 to 29.0% reported in other countries (3) and 12.8 to 14.1% in the reference sequences. The genetic diversity of the isolates from the six patients belonging to the "SP" subcluster was 3.8%, which is extremely low compared with the genetic diversity of 5.6% in a homosexual group in Spain (4). Furthermore, the V3 region genetic diversity in our Korean "SP" subcluster was 4.1%, which is lower than the interpatient variability range of 8.2 to 14.0% for unrelated viruses (15).
These results indicate that the viruses from the six patients infected inside Korea were closely related and might have been transmitted from one source. Although it was not revealed in the epidemiological investigation, there was suspicion of homosexual activity between two male patients (subjects KRB7051 and KRB8091) who once shared the same residence. HIV-2 infection and transmission inside Korea are rare and are restricted to specific areas.
ACKNOWLEDGMENTS
This project was supported by an intramural fund from the National Institute of Health of Korea.
REFERENCES
Birch, C. J., R. F. McCaw, D. M. Bulach, P. A. Revill, J. T. Carter, J. Tomnay, B. Hatch, T. V. Middleton, D. Chibo, M. G. Catton, J. L. Pankhurst, A. M. Breschkin, S. A. Locarnini, and D. S. Bowden. 2000. Molecular analysis of human immunodeficiency virus strains associated with a case of criminal transmission of the virus. J. Infect. Dis. 182:941-944.
Blanchard, A., S. Ferris, S. Chamaret, D. Guetard, and L. Montagnier. 1998. Molecular evidence for nosocomial transmission of human immunodeficiency virus from a surgeon to one of his patients. J. Virol. 72:4537-4540.
Breuer, J., N. W. Douglas, N. Goldman, and R. S. Daniels. 1995. Human immunodeficiency virus type 2 (HIV-2) env gene analysis: prediction of glycoprotein epitopes important for heterotypic neutralization and evidence for three genotype clusters within the HIV-2a subtype. J. Gen. Virol. 76:333-345.
Cilla, G., B. Rodes, E. Perez-Trallero, J. Arrizabalaga, and V. Soriano. 2001. Molecular evidence of homosexual transmission of HIV type 2 in Spain. AIDS Res. Hum. Retrovir. 17:417-422.
Damond, F., M. Worobey, P. Campa, I. Farfara, G. Colin, S. Matheron, F. Brun-Vezinet, D. L. Robertson, and F. Simon. 2004. Identification of a highly divergent HIV type 2 and proposal for a change in HIV type 2 classification. AIDS Res. Hum. Retrovir. 20:666-672.
Kanki, P. J., K. U. Travers, S. Mboup, C. C. Hsieh, R. G. Marlink, A. Gueye-Ndiaye, T. Siby, I. Thior, M. Hernandez-Avila, J. L. Sankale, I. Ndoye, and M. E. Essex. 1994. Slower heterosexual spread of HIV-2 than HIV-1. Lancet 343:943-946.
Kannangai, R., S. Ramalingam, K. J. Prakash, O. C. Abraham, R. George, R. C. Castillo, D. H. Schwartz, M. V. Jesudason, and G. Sridharan. 2000. Molecular confirmation of human immunodeficiency virus (HIV) type 2 in HIV-seropositive subjects in south India. Clin. Diagn. Lab. Immunol. 7:987-989.
Kim, S. S., E. Y. Kim, K. Y. Park, S. D. Suh, H. K. Park, Y. O. Shin, M. Bae, and J. S. Lee. 2000. Introduction of human immunodeficiency virus 2 infection into South Korea. Acta Virol. 44:15-22.
Kusagawa, S., Y. Imamura, A. Yasuoka, H. Hoshino, S. Oka, and Y. Takebe. 2003. Identification of HIV type 2 subtype B transmission in East Africa. AIDS Res. Hum. Retrovir. 19:1045-1049.
Machuca, R., L. B. Jorgensen, P. Theilade, and C. Nielsen. 2001. Molecular investigation of transmission of human immunodeficiency virus type 1 in a criminal case. Clin. Diagn. Lab. Immunol. 8:884-890.
Metzker, M. L., D. P. Mindell, X. M. Liu, R. G. Ptak, R. A. Gibbs, and D. M. Hillis. 2002. Molecular evidence of HIV-1 transmission in a criminal case. Proc. Natl. Acad. Sci. USA 99:14292-14297.
Ou, C. Y., C. A. Ciesielski, G. Myers, C. I. Bandea, C. C. Luo, B. T. Korber, J. I. Mullins, G. Schochetman, R. L. Berkelman, A. N. Economou, J. J. Witte, L. J. Furman, G. A. Satten, K. A. MacInnes, J. W. Curran, and H. W. Jaffe. 1992. Molecular epidemiology of HIV transmission in a dental practice. Science 256:1165-1171.
Pfutzner, A., U. Dietrich, U. von Eichel, H. von Briesen, H. D. Brede, J. K. Maniar, and H. Rubsamen-Waigmann. 1992. HIV-1 and HIV-2 infections in a high-risk population in Bombay, India: evidence for the spread of HIV-2 and presence of a divergent HIV-1 subtype. J. Acquir. Immune Defic. Syndr. 5:972-977.
Reeves, J. D., and R. W. Doms. 2002. Human immunodeficiency virus type 2. J. Gen. Virol. 83:1253-1265.
Sankale, J. L., R. S. de la Tour, B. Renjifo, T. Siby, S. Mboup, R. G. Marlink, M. E. Essex, and P. J. Kanki. 1995. Intrapatient variability of the human immunodeficiency virus type 2 envelope V3 loop. AIDS Res. Hum. Retrovir. 11:617-623.(Jeong-Gu Nam, Gab Jung Ki)