1995 Fiscal Year Final Research Report Summary
Study of the mechanism of in-vitro activation of complement and formation of cryoglobulin in the sera from patients with C type hepatitis
| Project/Area Number |
06807180
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| Research Category |
Grant-in-Aid for General Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Research Field |
Laboratory medicine
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| Research Institution | Osaka Medical College |
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Principal Investigator |
SHIMIZU Akira Osaka Medical College, Department of Clinical Pathology, Professor, 医学部, 教授 (00028581)
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| Co-Investigator(Kenkyū-buntansha) |
NAKANISHI Toyohumi Osaka Medical College Research Fellow, 医学部, 助手 (10247843)
HATANAKA Michiyo Osaka Medical College Research Fellow, 医学部, 助手 (50218484)
NAKAGAWA Toshimasa Osaka Medical College Assistant Professor, 医学部, 講師 (30237226)
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| Project Period (FY) |
1994 – 1995
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| Keywords | rheumatoid factor / hepatitis C virus / cryoglobulin / immune complex / complement activation in vitro / complement cold activatiomn / lymphocyte / chronic hepatitis |
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| Research Abstract |
The in vitro activation of the classical complement pathway at a low temperature has been reported as cold activation of complement since the mid 1970's, and it has been observed among patients with non-A non-B hepatitis. Subsequently, such cold activation was confirmed to be strongly associated with hepatitis C virus (HCV) infection. In addition to complement activaiton at a low temperature, types II and III cryoglobulin have been frequently found in HCV antibody-positive sera. The complement may be activated by an immune complex formed at a low temperature, and this phenomenon may be related to cryoglobulin. Cryoglobulin consists of IgM with rheumatoid factor (RF) activity and IgG,which reacts as an antigen against the IgM RF.We encountered a case in which RF in fresh serum was negative but became positive after the serum was kept in a refrigerator. This serum was HCV antibody-positive and showed complement activation in vitro at a low temperature. Herein, we examined whether the RF detected after cold storage is specific for HCV infection, and whether the titer of the RF increases when complement activity decreases in the sera.
Storage of sera at 4ﾟC elevated the titer of rheumatoid factor (RF) in some of the HCV-positive specimens, as measured by hephelometry with IgG-coated latex. This RF was not detected in HCV-negative sera. Most of the sera showing the cold-hependent elevation of RF had decreased complement hemolytic activity (CH50) after the cold storage. The RF elevated by cold storage decreased to the level of fresh sera by the addition of guinea pig serum as a complement supplement in a dose-dependent fashion. Thus, in some of the HCV-infected sera, the affinity of RF appears to be weak, and the binding between the RF and IgG coated on latex may be inhibited by complement components in fresh sera.
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Research Products
(8 results)
