2001 Fiscal Year Final Research Report Summary
Pitfalls in Neonatal Mass-screening for Cretinism - False hyperthyrotropinemia caused by human anti-mouse antibody (HAMA) of meternal origin
| Project/Area Number |
10670699
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Pediatrics
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| Research Institution | Asahikawa Medical College |
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Principal Investigator |
ITO Yoshiya Asahikawa Medical College, Pediatrics, Instructor, 医学部, 助手 (70241437)
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| Co-Investigator(Kenkyū-buntansha) |
ISHII Takuma Asahikawa Medical College, Pediatrics, Instructor, 医学部, 助手 (70312452)
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| Project Period (FY) |
1998 – 2000
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| Keywords | Neonatal Mass-Screening / TSH / HAMA / Cretinism / Anti-Mouse Antibody / false hyperthyrotropinemia |
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| Research Abstract |
We had two cases with falsely positive results in neonatal screening for congenital hypothyroidism.The TSH activity in the sera from both infants and mothers corresponded to the peak of serum IgG in size-exclusion HPLC analysis. However, no anti-TSH autoantibody was detected in these sera. The TSH levels decreased when the sera were treated with protein A or immunoabsorbed with anti-human IgG serum. Furthermore, the high levels of serum TSH were abolished by using sheep, but not mouse, anti-human TSH antibody as a capture antibody. These results demonstrate that placental transfer of maternal IgG class human anti-mouse antibody (HAMA) results in falsely elevated TSH levels in newborn sera in sandwich immunoassays using mouse anti-TSH monoclonal antibody.
We studied another cause of falsely positive elevation of TSH. Two boys and their mother had high TSH value with normal thyroid function. Elevation of TSH value in the boys were gradually diminished, so that placentally transferred substance may cause false hyperthyrotropinemia. In the TSH profile of HPLC analysis, two peaks are detected from sera of their mother. One peak corresponded to TSH molecule and another one is just near the TSH peak. The binding of extracted IgG with TSH was 37.2 %. We concluded these boys with falsely elevated TSH had anti-TSH autoantibody, which were transferred from their mother through placenta.
In the last year we did nation-wide survey to explore the incidence of false hyperthyrotropinemia in neonatal screening for congenital hypothyroidism. In this survey 160 (from 130 to 234) patients were reported to have congenital hypothyroidism each year in these 10 years. But we have only 3 cases with falsely elevated TSH value. It is very difficult to get the precise information about the cases with false hyperthyrotropinemia from the central laboratories in each prefectures.
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Research Products
(6 results)
