OBJECTIVE: Iodine deficiency was the likely cause of a high prevalence of goitre previously in Sri Lankan schoolchildren. Salt iodination was made compulsory in 1993 but there has been no recent study, using modern techniques, of its benefits or harmful effects. METHODS: Three hundred and sixty-seven schoolgirls between the ages of 11 and 16 years had ultrasound thyroid volume, free thyroxine (T4), free tri-iodothyronine (T3), thyrotrophin (TSH), anti-thyroglobulin (TgAb) and thyroid peroxidase (TPOAb) antibodies, and urine iodine concentrations measured. RESULTS: Median ultrasound thyroid volume ranged from 4.8 ml (11-year-old girls) to 8.6 ml (16-year-old girls) with an age-related increase. Median urine iodine concentrations ranged from 105 to 152 microg/l. Free T4 and free T3 were normal in all, but TSH was elevated in four subjects (5. 53-41.29 mU/l). However, the prevalence of TgAb was markedly raised, ranging between 14.3% (11-year-old girls) and 69.7% (16-year-old girls) (P<0.03). In contrast, the prevalence of TPOAb was 10% or less in all age groups. CONCLUSIONS: Normal median thyroid volumes, iodine concentrations and thyroid function would indicate that iodine deficiency is not a major problem in this group. The high prevalence of TgAb, hitherto unreported, most likely reflects excessive iodination of Tg resulting in increased immunogenicity. There is an urgent need to continuously monitor the adequacy and risks of iodination in this population.
LD Premawardhana, AB Parkes, PP Smyth, CN Wijeyaratne, A Jayasinghe, DG de Silva and JH Lazarus
P. P. A. Smyth, N. M. McMullan, B. Grubeck-Loebenstein and D. K. O'Donovan
Abstract. Thyroid growth stimulating immunoglobulins (TGI) were assayed in IgG concentrates prepared from human plasma using a cytochemical bioassay (CBA) based on the measurement of changes in glucose-6-phosphate dehydrogenase (G6PD) activity in guinea pig thyroid follicular cells. TGI was present in all 8 patients studied who had goitrous Graves' disease, in 9 who had toxic diffuse goitres with asymmetric uptake on scintigram and/or symptomatic ophthalmopathy and in 4:8 who had toxic uninodular goitre with autonomously functioning nodules. TGI were also present in 34:54 (64%) of patients who had non-toxic goitres. In contrast, TGI were undetectable in 4 patients who had Graves' disease without palpable goitre and in all 18 euthyroid non-goitrous volunteers. Maximum increases in G6PD activity occurred at an IgG concentration of 50 μg/ml in all patients who had goitrous Graves' disease and in 5:7 who had diffuse non-toxic goitres. In contrast, IgG concentrates from 20:27 patients with nodular goitres caused maximum increases in G6PD activity at an IgG concentration of 500 μg/ml. A comparison of the prevalence of TGI with that of thyroid stimulating immunoglobulins (TSI), also measured by CBA, in 63 patients showed that although both stimulators were present in 8 patients who had goitrous Graves' disease they were only simultaneously present in 18:43 (42%) who had non-toxic goitres of various aetiologies. Thyrotrophin receptor antibodies (TRAb) were present in 11/44 (25%) of non-toxic goitrous patients but there was no significant correlation with IgG stimulators in such patients. It is concluded that the finding of IgG stimulators in a variety of thyroid disorders suggests common immunological features in their pathogenesis. The presence or absence of such stimulators and their relative potencies may play a part in determining functional or structural variations between common forms of goitre.
B. Grubeck-Loebenstein, H. Kassal, P. P. A. Smyth, K. Krisch and W. Waldhäusl
Abstract. Thyroid growth stimulating immunoglobulins microsomal antibodies and antibodies against thyroglobulin were determined in patients with simple goitre (n = 20) and controls (n = 6) living in an iodine deficient area. In addition, lymphocytic infiltration of thyroid tissue, the amount of the various lymphocyte subsets (Leu 4+, Leu 3a+, and Leu 2a+ T-cells as well as B1+ B cells) in the thyroid gland, as well as the expression of the histocompatibility antigen HLA-DR on thyrocytes and intrathyroidal T-lymphocytes were examined. Goitrous patients were subdivided into two groups according to their individual iodine supply estimated by iodine excretion values, and immunological parameters were compared between patients with low (group A, iodine excretion < 70 μg/24 h) and with higher (group B, iodine excretion> 100 μg/24 h) iodine supply. Thyroid growth stimulating immunoglobulins and antithyroid antibodies were equally prevalent in the two patient groups, but were absent in controls. Lymphocytic infiltration of thyroid tissue was present to a comparable extent in patients of groups A and B, but to a distinctly lower degree in control persons. Intrathyroidal T-lymphocyte subsets did not differ between patients and controls. B-lymphocytes, germinal centres as well as DR+ thyrocytes were detected in goitrous patients of both groups, but never in control persons. Thus, immunological abnormalities frequently occur in patients with simple goitre and do not depend upon individual iodine supply.
P. P. A. Smyth, D. Neylan, N. M. McMullan, D. F. Smith and T.J. McKenna
Abstract. The rare occurrence of hyperthyroidism with an autonomously functioning nodule which following 131I therapy presented as toxic diffuse goitre (Graves' disease) is described in a 60 year old male. This progression was characterised by the presence of varying concentrations of IgG thyroid stimulators, thyroid stimulating immunoglobulins and thyroid growth stimulating immunoglobulins, as measured by cytochemical bioassay. It is postulated that the presence of the nodule and its associated hypersecretion of thyroid hormones may have protected the gland from the effects of IgG stimulators by bringing about inhibitory short-loop feedback on normal thyroid cells. It is further suggested that following therapeutic ablation of the nodule, normal thyroid cells became sensitive to the thyroid stimulators with the evolution of typical features of toxic diffuse goitre.
T. Joseph McKenna, Sean Cunningham, Marie Culliton, Leslie Daly, Aideen Moore, Fergal Magee and Peter P. A. Smyth
Abstract. Hyperprolactinaemic patients occasionally demonstrate hirsutism and elevated levels of DHA-S, a weak androgen of adrenal origin. Abnormal adrenal function is frequently observed in hirsute patients. These observations prompted speculation that prolactin may modulate normal adrenal secretion and that derangements of adrenal androgen secretion may be due to abnormalities in prolactin. In this study we examined the possibility that elevated prolactin levels may be involved in the pathogenesis of hyperandrogenaemia in hirsute patients. However, basal prolactin levels in hirsute women, with or without menstrual disturbances, 201 ± 24.3 mU/l (mean ± se) and 192 ± 24.3 mU/l respectively, were significantly suppressed below levels in normal women, 289 ± 12.2 mU/l. The prolactin responses to stimulation with TRH and to suppression with l-dopa were also studied in hirsute patients. The prolactin response to TRH (maximum increment or integrated response) was exaggerated significantly in hirsute women with menstrual disturbances when compared to normal women, to hirsute women with normal menses or to normal men. This abnormal response may have been due to elevated oestrone levels present in patients with oligomenorrhoea (318 ± 49.5 pmol/l compared to 191 ± 12.1 pmol/l in normal women and 161 ± 15.5 pmol/l in hirsute women with normal menses, P < 0.05). There were no abnormalities detected in the suppression of prolactin in response to l-dopa in any of these groups. These findings do not support a role for prolactin in the pathogenesis of hyperandrogenaemia in hirsute patients. However, elevated androgen levels in women may bring about suppression of basal prolactin levels to values seen in normal men. In addition elevated oestrone levels may exaggerate the stimulatory effect of TRH on prolactin secretion. as was seen in oligomenorrhoeic hirsute women.
P. M. Bell, D. G. Sinnamon, P. P. A. Smyth, H. A. Drexhage, M. Haire, G. F. Bottazzo and A. B. Atkinson
Abstract. A 37 year old male with a strong family history of autoimmune disease presented with typical symptoms of hyperthyroidism. He had exophthalmos but no goitre. Hyperthyroidism was confirmed by failure of 131I neck uptake to suppress after 7 days treatment with triiodothyronine. Six years previously a diagnosis of primary hypothyroidism has been made. At diagnosis of hyperthyroidism, thyroglobulin antibodies, thyroidal microsomal antibodies and thyroid stimulating immunoglobulins were detected. The absence of thyroid growth stimulating immunoglobulins and presence of immunoglobulins blockink TSH-induced growth may account for the absence of goitre throughout. HLA -B8, -B, -DR3 and -DR4 genotypes, low C4 complement cocentrations and islet cell autoantibodies were detected at the time of diagnosis and 1 year later diabetes mellitus developed.
G Mazziotti, LD Premawardhana, AB Parkes, H Adams, PP Smyth, DF Smith, WN Kaluarachi, CN Wijeyaratne, A Jayasinghe, DG de Silva and JH Lazarus
OBJECTIVE: To study the evolution of thyroid autoimmunity, in relation to the change in goitre prevalence, during 3 Years of iodine prophylaxis in Sri Lanka. METHODS: Two groups of Sri Lankan schoolgirls between the ages of 10.8 and 17.5 Years were studied in 1998 (401 girls) and 2001 (282 girls). A prospective study was performed in 42 schoolgirls who were thyroid autoantibody (Ab)-positive (+ve) in 1998. Anthropometric measures, urinary iodine excretion (UIE), thyroid Volume, free thyroxine, free tri-iodothyronine, TSH, and thyroglobulin (Tg) and thyroid peroxidase (TPO) Ab were evaluated in all 683 girls. RESULTS: Goitre prevalence was significantly lower in 2001 compared with 1998 related to age (2.9% compared with 20.2%) and body surface area (11.6% compared with 40.8%), although UIE was unchanged. Prevalence of thyroid Ab in 2001 was also lower (23.4% compared with 49.9%); among those with the Ab, 34.8% had TgAb alone and 46.9% had a combination of TgAb+TPOAb, compared with 82.0% TgAb alone in 1998. In 2001, subclinical hypothyroidism was more frequent in Ab+ve (6.3%) than Ab-negative girls (1.0%). A cohort of 42 Ab+ve schoolgirls in 1998 (34 with TgAb alone, eight with TgAb+TPOAb) were evaluated again in 2001. Only 10 of them (23.8%) remained Ab+ve (mostly TPOAb+/-TgAb) in 2001. CONCLUSIONS: This study demonstrates that: (1) in 2001, goitre prevalence and thyroid autoimmunity rates were significantly lower than in 1998; (2) the pattern of thyroid Ab was different in the two surveys; (3) in 2001 alone, the occurrence of hypothyroidism was correlated with the presence of thyroid autoimmunity. These results indicate an evolution of thyroid autoimmune markers during the course of iodine prophylaxis, which has not been described before.
V Estienne, C Duthoit, VD Costanzo, PJ Lejeune, M Rotondi, S Kornfeld, R Finke, JH Lazarus, U Feldt-Rasmussen, WG Franke, P Smyth, M D'Herbomez, B Conte-Devolx, L Persani, C Carella, Jourdain JR, M Izembart, ME Toubert, A Pinchera, A Weetman, R Sapin, P Carayon and J Ruf
OBJECTIVE: TGPO autoantibodies (aAbs) that bind simultaneously to thyroglobulin (Tg) and thyroperoxidase (TPO) are present in the serum of patients with autoimmune thyroid diseases (AITD) and have been found to differ from monospecific Tg and TPO aAbs. To obtain further insights on the prevalence defined as the rate of occurrence and significance of TGPO aAbs in a large population, we carried out a collaborative study involving 15 European teams. METHODS: Serum samples from 3122 patients with various thyroid and non-thyroid diseases and normal subjects were assayed using a novel TGPO aAb detection kit. This test was designed so that TGPO aAbs are trapped between the Tg-coated solid phase and the soluble TPO labeled with a radioiodinated monoclonal antibody. RESULTS: Only three out of the 220 normal subjects (prevalence of 1.4%) were found to have positive TGPO aAb levels, which were mainly observed in the patients with AITD: the group of patients suffering from Hashimoto's thyroiditis had a TGPO aAb prevalence of 40.5% (n=437 patients), those with Graves' disease, a prevalence of 34.6% (n=645) and those with post-partum thyroiditis, 16.0% (n=243). Among the non-AITD patients with positive TGPO aAb levels, the TGPO aAb prevalence ranged from 20.7% among those with thyroid cancer (n=246) to 0% among those with toxic thyroid nodules (n=47). Among the patients with non-thyroid diseases, the TGPO aAb prevalence ranged from 9.8% in the case of Biermer's pernicious anemia (n=78) to 0% in that of premature ovarian failure (n=44). It is worth noting that the groups showing the highest TGPO aAb prevalence also contained the patients with the highest TGPO aAb titers. Statistical comparisons between the TGPO aAb prevalences in the various groups showed that TGPO aAb could be used as a parameter to distinguish between the groups of Hashimoto's and Graves' patients and between the women with post-partum thyroiditis and the post-partum women with only Tg and/or TPO aAb established during early pregnancy. Unexpectedly, the correlations between TGPO aAbs and Tg and TPO aAbs were found to depend mainly on the assay kit used. CONCLUSION: High TGPO aAb titers are consistently associated with AITD but the reverse was not found to be true. TGPO aAbs are a potentially useful tool, however, for establishing Hashimoto's diagnosis, and would be worth testing in this respect with a view to using them for routine AITD investigations.
S R Ali, J Bryce, M Cools, M Korbonits, J G Beun, D Taruscio, T Danne, M Dattani, O M Dekkers, A Linglart, I Netchine, A Nordenstrom, A Patocs, L Persani, N Reisch, A Smyth, Z Sumnik, W E Visser, O Hiort, A M Pereira, S F Ahmed and on behalf of Endo-ERN
To identify cross-border international registries for rare endocrine conditions that are led from Europe and to understand the extent of engagement with these registries within a network of reference centres (RCs) for rare endocrine conditions.
Database search of international registries and a survey of RCs in the European Reference Network for rare endocrine conditions (Endo-ERN) with an overall response rate of 82%.
Of the 42 conditions with orphacodes currently covered within Endo-ERN, international registries exist for 32 (76%). Of 27 registries identified in the Orphanet and RD-Connect databases, Endo-ERN RCs were aware of 11 (41%). Of 21 registries identified by the RC, RD-Connect and Orphanet did not have a record of 10 (48%). Of the 29 glucose RCs, the awareness and participation rate in an international registry was highest for rare diabetes at 75 and 56% respectively. Of the 37 sex development RCs, the corresponding rates were highest for disorders of sex development at 70 and 52%. Of the 33 adrenal RCs, the rates were highest for adrenocortical tumours at 68 and 43%. Of the 43 pituitary RCs, the rates were highest for pituitary adenomas at 43 and 29%. Of the 31 genetic tumour RCs, the rates were highest for MEN1 at 26 and 9%. For the remaining conditions, awareness and participation in registries was less than 25%.
Although there is a need to develop new registries for rare endocrine conditions, there is a more immediate need to improve the awareness and participation in existing registries.