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Journal ArticleDOI

Human monoclonal thyroglobulin autoantibodies: epitopes and immunoglobulin genes.

TL;DR: The TgAb panel provides novel information regarding the repertoire of H chain genes encoding human TgAbs as well as the relationship between the H chains and the epitopes recognized on this major thyroid autoantigen.
Abstract: Autoantibodies to thyroglobulin (TgAbs) are common markers of thyroid autoimmunity, but relatively few human monoclonal TgAbs have been described. From a panel of 64 human monoclonal TgAbs (isolated from a thyroid-disease derived combinatorial Ig gene library), we selected seven with unique genetic features for detailed characterization. These TgAbs preferentially recognize native (not denatured) Tg, like serum autoantibodies. Most have high affinities for Tg (dissociation constant 10(-10) to 10(-9) m). Their light (L) chain Ig genes are not unusual, but four of the five heavy (H) chain genes are new. Moreover, one H chain belongs to the small VH2 family, not previously reported for autoantibodies to Tg or thyroid peroxidase. The TgAbs inhibit the binding to Tg of the thyroid donor's serum autoantibodies, indicating epitopic overlap. Competition analysis (surface plasmon resonance) shows that the TgAbs recognize overlapping epitopes in an immunodominant region on the Tg dimer ( approximately 660 kDa). Two major and several minor epitopic regions were defined, each associated with a particular H + L chain combination. In conclusion, our TgAb panel provides novel information regarding the repertoire of H chain genes encoding human TgAbs as well as the relationship between the H chains and the epitopes recognized on this major thyroid autoantigen.

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Citations
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Journal ArticleDOI
TL;DR: Results of TgAb from P TC-T are more concordant than those from PTC because their epitope pattern is more restricted, and Discrepancy is lower when comparing assays with similar methodology.
Abstract: Context: Thyroglobulin autoantibodies (TgAb) have been proposed as a surrogate marker of thyroglobulin in the follow-up of differentiated thyroid carcinoma. Commercially available TgAb assays are often discordant. We investigated the causes of discrepancy. Design: TgAb were measured by three noncompetitive immunometric assays and three competitive RIA in 72 patients with papillary thyroid carcinoma and associated lymphocytic thyroiditis (PTC-T), 105 with papillary thyroid carcinoma and no lymphocytic thyroiditis (PTC), 160 with Hashimoto's thyroiditis, and in 150 normal subjects. The results of the six assays were correlated. TgAb epitope pattern, evaluated by inhibition of serum TgAb binding to thyroglobulin by TgAb-Fab regions A, B, C, and D, were compared in sera which were positive in all six assays (concordant sera) and positive in only one to five assays (discordant sera) were compared. TgAb International Reference Preparation (IRP) was measured in 2007 and 2009. Results: The correlations of the six...

48 citations


Cites background or methods or result from "Human monoclonal thyroglobulin auto..."

  • ...0) in Tg-coated ELISA wells (60 min at room temperature) (24)....

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  • ...The epitope pattern of 87 (37 PTC-T, 10 PTC, and 40 HT) sera was evaluated by inhibiting serum TgAb binding to Tg by each single TgAb-Fab in ELISA, as previously reported (2, 24, 25)....

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  • ...ognize four different, partially overlapping Tg regions (24, 25)....

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  • ...Cloning and characterization of human recombinant monoclonal TgAb expressed as Fab has been previously reported (23, 24)....

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  • ...32 (region D)] (24) were employed in the present study....

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Journal ArticleDOI
TL;DR: It is shown that the unmasking of a cryptic epitope on Tg contributes to iodine-induced thyroid autoimmunity in humans and plays a major role in the association of PTC with Hashimoto's thyroiditis, as a consequence of the autoimmune process leading to a progressive increase of serum TSH in these patients.
Abstract: This review focuses on two different topics: (a) iodine and autoimmune thyroid disease (AITD) and (b) AITD and papillary thyroid carcinoma (PTC). Iodine intake modifies the expression of thyroid diseases and has been associated with induction of AITD. Thyroglobulin (Tg) is an important target in iodine-induced autoimmune response due to post-translational modifications of iodinated Tg, as suggested in animal models. We have shown that the unmasking of a cryptic epitope on Tg contributes to iodine-induced thyroid autoimmunity in humans. The relationship between AITD and PTC has been suggested in many studies. The presence of two different mechanisms has been hypothesized, one typical of AITD and the other of an immune reaction to PTC. We have shown that in AITD, the pattern of Tg recognition by anti-Tg antibodies (TgAb) is ‘restricted' to the immunodominant regions of Tg, while in patients with non-AITD, such as nodular goiter and PTC devoid of thyroid lymphocytic infiltration at histology, TgAb show a less restricted epitopic pattern and bind also to other regions of Tg. Thyroid function may also affect the frequency of PTC, the risk of cancer increasing with serum TSH levels. We have shown that this mechanism, rather than thyroiditis per se, plays a major role in the association of PTC with Hashimoto's thyroiditis, as a consequence of the autoimmune process leading to a progressive increase of serum TSH in these patients.

39 citations

Journal ArticleDOI
TL;DR: Selenium completed with L-thyroxine is a suitable therapy for patients with autoimmune thyroiditis and an inverse correlation was found between antioxidant capacity and the level of antithyroid peroxidase antibodies.
Abstract: A szelen nelkulozhetetlen nyomelem, amely antioxidans hatasa reven lenyeges az immun- es az endokrin rendszer műkodeseben. A pajzsmirigy hormonszintezise soran kepződő szabad gyokoknek szerepuk lehet a thyreoidea autoimmun betegsegeiben. A vizsgalat celja az volt, hogy meghatarozzak, a szelenkezeles hat-e a pajzsmirigy-peroxidaz, a tireoglobulin elleni antitestek szintjere es az antioxidans statusra. Modszer: Szazharmincket autoimmun thyreoiditises betegben kettős vakmodszerrel teszteltek a szelen hatasait. Mindket csoportban alkalmaztak L-tiroxin-szubsztitucios kezelest, igy a TSH-szint az elettani tartomanyban maradt. A kezelt csoportba 70 beteg (68 nő, atlageletkor 41,4 ± 9,5 ev), a placebocsoportba 62 beteg (61 nő, atlageletkor 42,7 ± 8,3 ev) tartozott. A TSH, az fT4, az fT3 es az antitestek mereset kemilumineszcens technikaval vegeztek. A teljes antioxidans-kapacitast Randox kittel, a szerumszelenszintet atomabszorpcios modszerrel hataroztak meg. A kezeles soran a vizsgalt betegek 2 × 100 µg L-szelen...

27 citations

Journal ArticleDOI
13 Jun 2016-Thyroid
TL;DR: In the in vitro study, low levels of TgAb do not preclude Tg measurement in vitro, but they can be associated with an undetectable Tg in DTC patients with residual thyroid tissue after thyroidectomy, however, the finding of low Levels of TGAb by sensitive assays associated withAn undetectables Tg rules out metastatic disease.
Abstract: Background: The management of patients with differentiated thyroid carcinoma (DTC) showing low levels of serum thyroglobulin autoantibodies (TgAb) and undetectable Tg after thyroidectomy is unsettled. This study sought to elucidate the clinical significance of low levels of TgAb and to evaluate their interference with Tg measurement in vitro. Methods: Tg and TgAb levels were correlated with the post-thyroidectomy staging of 177 consecutive DTC patients undergoing 131I ablation after total thyroidectomy (clinical study). Tg was measured by an immunometric assay (functional sensitivity: 0.1 ng/mL), and TgAb were evaluated by six assays (functional sensitivities: 1.2–96 IU/mL; positive cutoffs: 4–150 IU/mL). The changes in Tg concentration (Tg recovery) of diluted specimens from DTC patients were also measured after incubation with 67 sera from DTC patients with undetectable Tg and low levels of TgAb (in vitro study). DTC sera containing Tg were diluted serially (from 330 to 0.1 ng/mL) and incubated with TgA...

26 citations


Cites background from "Human monoclonal thyroglobulin auto..."

  • ...Positive TgAb are suggestive of autoimmune thyroid disease (30,31,13,14,15)....

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01 Jan 2008
TL;DR: The role of selenium is important because the level of free oxygen radicals is elevated in physiological thyroid hormone synthesis as discussed by the authors, which can have complex effects on the endocrine and immune system by its antioxidant capacity.
Abstract: A szelen nelkulozhetetlen nyomelem, amely antioxidans hatasa reven lenyeges az immun- es az endokrin rendszer műkodeseben. A pajzsmirigy hormonszintezise soran kepződő szabad gyokoknek szerepuk lehet a thyreoidea autoimmun betegsegeiben. A vizsgalat celja az volt, hogy meghatarozzak, a szelenkezeles hat-e a pajzsmirigy-peroxidaz, a tireoglobulin elleni antitestek szintjere es az antioxidans statusra. Modszer: Szazharmincket autoimmun thyreoiditises betegben kettős vakmodszerrel teszteltek a szelen hatasait. Mindket csoportban alkalmaztak L-tiroxin-szubsztitucios kezelest, igy a TSH-szint az elettani tartomanyban maradt. A kezelt csoportba 70 beteg (68 nő, atlageletkor 41,4 ± 9,5 ev), a placebocsoportba 62 beteg (61 nő, atlageletkor 42,7 ± 8,3 ev) tartozott. A TSH, az fT4, az fT3 es az antitestek mereset kemilumineszcens technikaval vegeztek. A teljes antioxidans-kapacitast Randox kittel, a szerumszelenszintet atomabszorpcios modszerrel hataroztak meg. A kezeles soran a vizsgalt betegek 2 × 100 µg L-szelen-metionin tablettat kaptak. A betegek klinikai es laboratoriumi vizsgalatat haromhavonta vegeztek egy even at. Eredmenyek: A szelenszint a betegek szerumaban lenyegesen alacsonyabb volt, mint az egeszseges kontrollokban. Az fT3/fT4 arany magasabb volt a szelennel kezeltekben, mint a placebocsoportban. A szelen hatasara az autoantitestek (főleg a pajzsmirigy-peroxidazenzim elleni antitestek) titere szignifikansan csokkent a megfigyelesi idő vegere. Inverz osszefuggest talaltak az antioxidans status es a pajzsmirigy-peroxidazenzim elleni antitestek titere kozott. A pajzsmirigy terfogata a kezelt betegekben nem csokkent jelentősen. Mellekhatast a kezeles soran nem tapasztaltak. Kovetkeztetes: A szelenkezeles autoantitest-kepzest gatlo hatasa miatt alkalmas az autoimmun thyreoiditises betegek kezelesere. | Selenium as an essential trace element is capable of exerting complex effects on the endocrine and immune system by its antioxidant capacity. The role of selenium is important because the level of free oxygen radicals is elevated in the physiological thyroid hormone synthesis. The aim of study was to determine whether selenium therapy can influence the level of antithyroid peroxidase and antithyroglobulin antibodies or whether there is a correlation between antioxidant capacity and the titer of autoantibodies. Method: 132 patient with autoimmune thyroiditis were investigated in a prospective, blind and placebo-controlled study. L-thyroxine substitution therapy was made in both groups and the level of TSH remained in the normal range. The selenium-treated group (n = 70 patients, 68 female, mean age 41,4 ± 9,5 year) was compared with the placebo-treated group (n = 62 patients, 61 female, mean age 42,7 ± 8,3 year). Selenium therapy was continued by L-seleno-methionine (per os 2 × 100 µg/day) for one year. Determination of TSH, fT4, fT3 and autoantibodies was carried out by chemiluminescence method. Total antioxidant capacity was determined by Randox kit, the level of selenium in the sera by atomic absorption technique was measured. In the follow-up study, patients were controlled every third month and at the end of a one-year observation period. Results: The level of selenium in the untreated patients was significantly lower than in treated patients and controls. The fT3/fT4 ration proved to be higher in patients after selenium therapy. The titer of antithyroid antibodies (mostly the antithyroid peroxidase) significantly decreased at the end of the study. An inverse correlation was found between antioxidant capacity and the level of antithyroid peroxidase antibodies. The volume of thyroid gland slightly diminished in treated patients. Side effects were not observed. Conclusions: Selenium completed with L-thyroxine is a suitable therapy for patients with autoimmune thyroiditis.

25 citations

References
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Journal ArticleDOI
TL;DR: The polymerase chain reaction and VH family-based primers are used to clone and sequence 74 human germline VH segments from a single individual and a directory is built to include all known germline sequences.

1,003 citations

Journal ArticleDOI
TL;DR: The RIA method used in this study provided more clinically appropriate serum Tg values in the group of TgAb-positive patients with metastatic DTC and may be an additional clinically useful tumor marker parameter for following T gAb- positive patients.
Abstract: The prevalence of circulating thyroid autoantibodies (TgAb or antithyroid peroxidase) was increased nearly 3-fold in patients with differentiated thyroid cancers (DTC) compared with the general population (40% vs. 14%, respectively). Serum TgAb (with or without antithyroid peroxidase) was present in 25% of DTC patients and 10% of the general population. Serial postsurgical serum TgAb and serum Tg patterns correlated with the presence or absence of disease. Measurements of serum Tg were made in 87 TgAb-positive sera by a RIA and two immunometric assay (IMA) methods to study TgAb interference. TgAb interference, defined as a significant intermethod discordance (>41.7% coefficient of variation) between the Tg RIA and Tg IMA values relative to TgAb-negative sera, was found in 69% of the TgAb-positive sera. TgAb interference was characterized by higher Tg RIA vs. IMA values and was, in general, more frequent and severe in sera containing high TgAb concentrations. However, some sera displayed marked interference when serum TgAb was low (1-2 IU/mL), whereas other sera with very high TgAb values (>1000 IU/mL) displayed no interference. An agglutination method was found to be too insensitive to detect low TgAb concentrations (1-10 IU/mL) causing interference. Exogenous Tg recovery tests were an unreliable means for detecting TgAb interference. Specifically, the exogenous Tg recovered varied with the type and amount of Tg added and the duration of incubation employed. Further, recoveries of more than 80% were found for some sera displaying gross serum RIA/IMA discordances. The measurement of serum Tg in DTC patients with circulating TgAb is currently problematic. It is important to use a Tg method that provides measurements that are concordant with tumor status. IMA methods are prone to underestimate serum when TgAb is present, increasing the risk that persistent or metastatic DTC will be missed. The RIA method used in this study provided more clinically appropriate serum Tg values in the group of TgAb-positive patients with metastatic DTC. Furthermore, as serial serum TgAb measurements paralleled serial serum Tg RIA measurements, TgAb concentrations may be an additional clinically useful tumor marker parameter for following TgAb-positive patients. Disparities between serial serum Tg and TgAb measurements might alert the physician to the possibility of TgAb interference with the serum Tg measurement and prompt a more cautious use of such data for clinical decision-making.

515 citations

Journal ArticleDOI
TL;DR: The first report of the physical linkage of the variable and constant loci of a human Ig gene family is provided by demonstrating that the most proximal known human VH segments lie within 100 kb of the constant region locus.
Abstract: We present a detailed analysis of the content and organization of the human immunoglobulin VH locus. Human VH genes representing five distinct families were isolated, including novel members belonging to two out of three of the known VH gene families (VH1 and VH3) as well as members of three new families (VH4, VH5, and VH6). We report the nucleotide sequence of 21 novel human VH genes, many of which belong to the three new VH gene families. In addition, we provide a preliminary analysis of the organization of these gene segments over the full extent of the locus. We find that the five multi-segment families (VH1-5) have members interspersed over nearly the full 1500-2000 kb of the VH locus, and estimate that the entire heavy chain locus covers 2500 kb or less. Finally, we provide the first report of the physical linkage of the variable and constant loci of a human Ig gene family by demonstrating that the most proximal known human VH segments lie within 100 kb of the constant region locus.

458 citations

Journal ArticleDOI
TL;DR: Comparison with 236 rearranged sequences revealed that no more than 24 of these germ‐line sequences could be assigned rearranged counterparts, that some of these were rarely used, and that only about 11 sequences are used frequently, suggesting that the expressed Vχ repertoire is mainly derived from a limited number of segments.
Abstract: From the genomic DNA of a single individual, we have amplified, cloned and sequenced 37 human germ-line V kappa segments. Four of these segments were new. We then compiled a comprehensive directory of all germ-line V kappa segments and identified 50 different sequences with open reading frames. Comparison with 236 rearranged sequences revealed that no more than 24 of these germ-line sequences could be assigned rearranged counterparts, that some of these were rarely used, and that only about 11 sequences are used frequently. This suggests that the expressed V kappa repertoire is mainly derived from a limited number of segments. Most surprisingly, the J kappa-distal region of the locus appears to be rarely used: we could unambiguously assign 162 rearranged sequences to V kappa segments of the J kappa-proximal region, but only 5 to segments of the J kappa-distal region.

405 citations

Journal ArticleDOI
TL;DR: A large group of patients with differentiated thyroid carcinoma who had serum thyroid peroxidase, thyroglobulin, or TSH-receptor antibodies due to coexistent thyroid autoimmune disease were studied, finding gradual disappearance of antibodies gradually disappeared in most patients.
Abstract: Le malattie autoimmuni della tiroide sono caratterizzate dalla presenza di anticorpi diretti contro la tireoperossidasi (TPO), la tireoglobulina (Tg) e il recettore per l’ormone tireotropo (TSH-R). Questo studio ha valutato se la rimozione completa degli antigeni tiroidei fosse in grado di indurre la scomparsa dei segni di autoimmunita tiroidea circolante. Lo studio e basato su una revisione retrospettiva delle cartelle cliniche di pazienti che erano stati seguiti e trattati secondo un protocollo standard. Sono stati studiati 182 pazienti affetti da tumore differenziato della tiroide i quali, per la coesistenza di una tiroidite cronica autoimmune, di un morbo di Basedow o di una tiroidite focale autoimmune, risultavano positivi per anticorpi anti-TPO (TPOAb), anti-Tg (TgAb) o anti-TSH-R (TRAb). Dei 182 soggetti, 151 erano di sesso femminile e 31 di sesso maschile; l’eta media era di 39,7±13,7 anni, con un range da 6 a 81 anni. Tutti i pazienti sono stati sottoposti a tiroidectomia totale e a trattamento con iodio radioattivo allo scopo di ablare il tessuto tiroideo residuo o metastatico. Il follow-up e stato effettuato mediante scintigrafie corporee totali con radioiodio e dosaggio della Tg circolante. La media del follow-up era di 10,1±4,1 anni, con un range di 4–20 anni. A seguito del trattamento con tiroidectomia totale e iodio radioattivo, si e verificata la scomparsa dei TgAb, TPOAb e TRAb. La mediana di scomparsa e stata di 6,3 anni per iTPOAb e di 3,0 anni per i TgAb. La scomparsa del tessuto tiroideo e quella degli anticorpi antitiroide erano correlate in modo statisticamente significativo. La persistenza di TPOAb e TgAb non veniva influenzata dal sesso, dall’eta e dalla concomitanza della tiroidite autoimmune o del morbo di Basedow.

318 citations

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