Effect of thyroglobulin autoantibodies on the clearance of serum thyroglobulin in humans Francesco Latrofa, MD1, Debora Ricci, PhD1, Sara Bottai, MD1, Paolo Piaggi, PhD2, Michele Marinò, MD1, Paolo Vitti, MD1 1Endocrinology Unit I, Department of Clinical and Experimental Medicine, University Hospital of Pisa, Italy 2Phoenix Epidemiology and Clinical Research Branch, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Phoenix, AZ To establish whether TgAb influence Tg clearance in humans, we correlated serum TgAb and Tg shortly after 131I treatment. Samples were taken at the time of 131I treatment and at intervals of 15 days thereafter (up to 90 days) in 30 consecutive patients undergoing 131I treatment because of Graves’ hyperthyroidism. Tg was measured by an IMA (functional sensitivity 0.1 ng/mL), TgAb by an IMA (analytical sensitivity 6 IU/mL). Tg was detectable in all patients at day 0. The concentrations of Tg rose from 33.2 (17.8-61.0) ng/mL at day 0 to 214.6 (116.9-393.4 ng/mL) at day 30 and then steadily decreased, reaching the lowest concentration at day 90 (10.9 [5.5-20.9] ng/mL). Compared to their levels at day 0 (23.6 [10.5-52.9] IU/mL), TgAb remained stable through 15 day and then gradually increased up to 116.6 (51.9-262.2) IU/mL at day 90. Patients were then split into two groups: with undetectable (<6 UI/l) (9 patients) or detectable (≥6) (21 patients) TgAb at day 0. Compared to the other cohort, patients with detectable TgAb showed significantly lower Tg concentrations at day 0 (20.3 [10.1-40.2] vs. 101.8 [36.6-279.8] ng/mL), similar at day 15, lower at day 30 (146.5 [74.3-287.8] vs. 514.8 [187.8-1407.9] ng/mL), at day 45 (87.5 [43.1-176.6] vs. 337.9 [120.1-947.0] ng/mL), at day 60 (61.6 [31.0-121.4] vs. 255.8 [79.0-823.8] ng/mL) and at day 75 (24.5 [11.9-49.2] vs. 249.5 [63.5-971.1] ng/mL) and similar at day 90. Compared to other patients, those with detectable TgAb showed a lower (182.5 [92.0-361.0] vs. 514.8 [187.8-1407.9] ng/mL) and an earlier (day 15 vs. day 30) peak of Tg. The mean of AUC of Tg concentrations was higher in patients with undetectable TgAb (36883 ± 44625 ng/mL) compared to the other group (17340 ± 16481 ng/mL) (p=0.02). In conclusion, TgAb modify the changes in Tg concentrations observed immediately after 131I treatment, inducing lower levels and a precocious peak of Tg. These observations indicate that TgAb influence significantly Tg clearance in humans because they remove Tg from serum and support the concept that TgAb interference on Tg measurement is mainly due to an in vivo effect and not to analytical interference.
Effect of thyroglobulin autoantibodies on the clearance of serum thyroglobulin in humans
Francesco Latrofa;Debora Ricci;Paolo Piaggi;Michele Marinò;Paolo Vitti
2018-01-01
Abstract
Effect of thyroglobulin autoantibodies on the clearance of serum thyroglobulin in humans Francesco Latrofa, MD1, Debora Ricci, PhD1, Sara Bottai, MD1, Paolo Piaggi, PhD2, Michele Marinò, MD1, Paolo Vitti, MD1 1Endocrinology Unit I, Department of Clinical and Experimental Medicine, University Hospital of Pisa, Italy 2Phoenix Epidemiology and Clinical Research Branch, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Phoenix, AZ To establish whether TgAb influence Tg clearance in humans, we correlated serum TgAb and Tg shortly after 131I treatment. Samples were taken at the time of 131I treatment and at intervals of 15 days thereafter (up to 90 days) in 30 consecutive patients undergoing 131I treatment because of Graves’ hyperthyroidism. Tg was measured by an IMA (functional sensitivity 0.1 ng/mL), TgAb by an IMA (analytical sensitivity 6 IU/mL). Tg was detectable in all patients at day 0. The concentrations of Tg rose from 33.2 (17.8-61.0) ng/mL at day 0 to 214.6 (116.9-393.4 ng/mL) at day 30 and then steadily decreased, reaching the lowest concentration at day 90 (10.9 [5.5-20.9] ng/mL). Compared to their levels at day 0 (23.6 [10.5-52.9] IU/mL), TgAb remained stable through 15 day and then gradually increased up to 116.6 (51.9-262.2) IU/mL at day 90. Patients were then split into two groups: with undetectable (<6 UI/l) (9 patients) or detectable (≥6) (21 patients) TgAb at day 0. Compared to the other cohort, patients with detectable TgAb showed significantly lower Tg concentrations at day 0 (20.3 [10.1-40.2] vs. 101.8 [36.6-279.8] ng/mL), similar at day 15, lower at day 30 (146.5 [74.3-287.8] vs. 514.8 [187.8-1407.9] ng/mL), at day 45 (87.5 [43.1-176.6] vs. 337.9 [120.1-947.0] ng/mL), at day 60 (61.6 [31.0-121.4] vs. 255.8 [79.0-823.8] ng/mL) and at day 75 (24.5 [11.9-49.2] vs. 249.5 [63.5-971.1] ng/mL) and similar at day 90. Compared to other patients, those with detectable TgAb showed a lower (182.5 [92.0-361.0] vs. 514.8 [187.8-1407.9] ng/mL) and an earlier (day 15 vs. day 30) peak of Tg. The mean of AUC of Tg concentrations was higher in patients with undetectable TgAb (36883 ± 44625 ng/mL) compared to the other group (17340 ± 16481 ng/mL) (p=0.02). In conclusion, TgAb modify the changes in Tg concentrations observed immediately after 131I treatment, inducing lower levels and a precocious peak of Tg. These observations indicate that TgAb influence significantly Tg clearance in humans because they remove Tg from serum and support the concept that TgAb interference on Tg measurement is mainly due to an in vivo effect and not to analytical interference.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
