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COMPLEMENT COMPONENT C9 IN GRAVES' DISEASE
Author(s) -
OLEESKY D. A.,
RATANACHAIYAVONG S.,
LUDGATE M.,
MORGAN B. P.,
CAMPBELL A. K.,
MCGREGOR A. M.
Publication year - 1986
Publication title -
clinical endocrinology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.055
H-Index - 147
eISSN - 1365-2265
pISSN - 0300-0664
DOI - 10.1111/j.1365-2265.1986.tb03617.x
Subject(s) - graves' disease , medicine , endocrinology , immunoradiometric assay , thyroid , monoclonal antibody , carbimazole , pathogenesis , antibody , complement system , thyroid disease , chemistry , immunology , radioimmunoassay
SUMMARY C9, the terminal component of complement, is the key part of the membrane attack complex formed as a result of complement activation; it has also been reported to be an acute phase protein. Its potential role in Graves' disease has been studied by measuring plasma C9 concentrations using an automated two‐site immunoradiometric assay employing monoclonal antibodies, whose binding to thyroid tissue has also been investigated. The plasma C9 concentration in patients with hyperthyroid Graves' disease (86.3 ± 21.6 mg/L mean±SD; n = 49) was significantly increased ( P < 0.001) compared with normal subjects (60.4 ± 13.4 mg/l; n = 48). In contrast, the plasma concentration of C‐reactive protein, a marker of the acute phase response, was not significantly different between the two groups. The plasma C9 concentration in patients with hyperthyroid Graves' disease decreased significantly ( P < 0.01) after treatment with antithyroid drugs (carbimazole or methimazole; n = 14), but not after radioactive iodine ( 131 I) treatment (n = 18). Immunohistochemical staining demonstrated that monoclonal antibody to C9 bound to the basement membranes of thyroid follicular cells of Graves' thyroid tissue but not to normal thyroid tissue. Radiolabeled monoclonal antibody to C9 bound to membrane fragments prepared from thyroid glands from two patients with Graves' disease. We conclude that C9, and by implication the membrane attack complex, may be involved in the pathogenesis of Graves' disease.