[1] Division of Gastroenterology,
[2] Department of Internal Medicine,undefined
[3] Institute of Clinical Medicine,undefined
[4] University of Tsukuba,undefined
[5] 1-1-1 Tennodai,undefined
[6] Tsukuba 305-8575,undefined
[7] Japan,undefined
[8] Department of Pathology,undefined
[9] Institute of Basic Medicine,undefined
[10] University of Tsukuba,undefined
[11] Tsukuba,undefined
[12] Japan,undefined
[13] Division of Pathology,undefined
[14] Ibaraki Prefectural Central Hospital and Cancer Center,undefined
[15] Ibaraki,undefined
[16] Japan,undefined
[17] AIDS Research Center,undefined
[18] National Institute of Infectious Diseases,undefined
[19] Tokyo,undefined
[20] Japan,undefined