Elevated anti-alpha-galactosyl antibody titres. A marker of progression in autoimmune thyroid disorders and in endocrine ophthalmopathy?
; Malaise, Michel ; et al
in Acta Endocrinologica (1987), 115(1), 67-74
The titres of anti-alpha-galactosyl antibodies were measured by passive haemagglutination in 50 control subjects and in 128 patients presenting with various thyroid disorders. Titres of control subjects ... [more ▼]
The titres of anti-alpha-galactosyl antibodies were measured by passive haemagglutination in 50 control subjects and in 128 patients presenting with various thyroid disorders. Titres of control subjects ranged from 1/10 to 1/80, regardless of age and blood group. Elevated titres (greater than 1/80) were constantly noted in 6/6 patients with progressive exophthalmos, in 5/5 patients with untreated Graves' disease, and in 11/12 patients with progressive nontoxic goitre. By contrast, the titres were within the normal range in primary myxoedema (17 patients) and in residual exophthalmos (11 patients), whereas they were only erratically increased in 1/31 patients with treated or cured Graves' disease and in 5/36 patients with nonprogressive nontoxic goitre. Finally, elevated titres were also found in 3/7 patients presenting with autoimmune thyroiditis. No correlations could be established between elevated titres and the thyrotropin binding inhibiting immunoglobulin activity, the antithyroglobulin antibody titres or the antimicrosomal antibody titres. As in the control subjects, the anti-alpha-galactosyl antibodies mainly belonged to the IgG class. Affinity purified anti-alpha-galactosyl antibodies were capable of binding to trypsinized human and porcine thyroid cells in culture, as shown by indirect immunofluorescence. On the other hand, they were not able to react with untreated thyroid cells. The data show that the measurement of anti-alpha-galactosyl antibody titres could represent an easy and useful tool to determine whether an autoimmune thyroid disorder is in progression. Besides, they suggest that some of the antigenic determinants implicated in the enhanced production of anti-alpha-galactosyl antibodies are present, but normally hidden, within the cell surface of thyroid cells. [less ▲]Detailed reference viewed: 1 (0 ULg)
Synthesis of basement membrane components by differentiated thyroid cells.
; Nusgens, Betty ; Foidart, Jean-Michel et al
in Biochimica et Biophysica Acta (1985), 846(2), 257-64
Morphological studies indicate that basement membrane formation or maintenance can be achieved in cultures of thyroid cells. In the present investigation we have studied the biosynthesis of this ... [more ▼]
Morphological studies indicate that basement membrane formation or maintenance can be achieved in cultures of thyroid cells. In the present investigation we have studied the biosynthesis of this extracellular matrix by differentiated porcine thyroid cells in culture. They were prepared by two procedures: (1) thyroid cells isolated by dispase digestion of the thyroid gland were maintained in serum-free medium on poly(L-lysine) coated dishes; (2) thyroid follicles released by collagenase treatment of the gland were isolated by differential filtration and cultured in suspension on agarose-coated dishes. In both cases, functional follicular-like structures were obtained as shown by their ability to organify Na125I and to respond to thyrotropin stimulation (250 microU/ml). After incubating the cells with radiolabeled proline or methionine, collagen synthesis was observed with the two types of culture, as shown by the formation of radioactive hydroxyproline and by the synthesis of peptides with electrophoretic properties identical to those of authentic collagen molecules and susceptible to collagenase. Besides variable amounts of type I and type III collagen-like peptides, significant proportions of labeled peptides migrated with type IV collagen chains and were precipitated by anti-type IV collagen antibody; thyrotropin had no significant effect either on the total collagen synthesis or on the relative amounts of the different collagen peptides. When thyroid cells were incubated with [35S]sulfate, a labeled glycosaminoglycan with chromatographic properties analogous to that of heparan sulfate could be obtained in both culture conditions; here again, no effect of thyrotropin was observed. The ability of differentiated porcine thyroid cells to synthesize basement membrane was suggested by their production of type IV collagen and heparan sulfate, two of its potential components. Thyrotropin, which drastically enhanced the functional property of the cells, did not seem to regulate this synthesis. [less ▲]Detailed reference viewed: 2 (0 ULg)