1. Immunology Division and Division of Molecular Virology, Jichi Medical School, Tochigi-Ken 329-0498,1
2. Department of Medical Sciences, Toshiba General Hospital, Tokyo 140-8522,2
3. Aikawa Internal Hospital, Ibaraki-Ken 310-0851,3
4. Department of Internal Medicine, Iwaki Kyoritsu General Hospital, Fukushima-Ken 973-8402,4
5. Department of Clinical Pathology, Kanazawa National Hospital, Ishikawa-Ken 920-0935,5
6. First Department of Internal Medicine, Yamanashi Medical University, Yamanashi-Ken 409-3898,6
7. Japanese Red Cross Saitama Blood Center, Saitama-Ken 338-0001,7 and
8. Miyakawa Memorial Research Foundation, Tokyo 107-0062,8 Japan