Practical implementation of automated closed-loop insulin delivery: A French position statement

Automated closed-loop (CL) insulin therapy has come of age. This major technological advance is expected to significantly improve the quality of care for adults, adolescents and children with type 1 diabetes. To improve access to this innovation for both patients and healthcare professionals (HCPs), and to promote adherence to its requirements in terms of safety, regulations, ethics and practice, the French Diabetes Society (SFD) brought together a French Working Group of experts to discuss the current practical consensus. The result is the present statement describing the indications for CL therapy with emphasis on the idea that treatment expectations must be clearly defined in advance. Specifications for expert care centres in charge of initiating the treatment were also proposed. Great importance was also attached to the crucial place of high-quality training for patients and healthcare professionals. Long-term follow-up should collect not only metabolic and clinical results, but also indicators related to psychosocial and human factors. Overall, this national consensus statement aims to promote the introduction of marketed CL devices into standard clinical practice.

Unraveling the intrafamilial correlations and heritability of tumor types in MEN1: a Groupe d'étude des Tumeurs Endocrines study

BACKGROUND

MEN1, which is secondary to the mutation of the MEN1 gene, is a rare autosomal-dominant disease that predisposes mutation carriers to endocrine tumors. Most studies demonstrated the absence of direct genotype-phenotype correlations. The existence of a higher risk of death in the Groupe d'étude des Tumeurs Endocrines-cohort associated with a mutation in the JunD interacting domain suggests heterogeneity across families in disease expressivity. This study aims to assess the existence of modifying genetic factors by estimating the intrafamilial correlations and heritability of the six main tumor types in MEN1.

METHODS

The study included 797 patients from 265 kindred and studied seven phenotypic criteria: parathyroid and pancreatic neuroendocrine tumors (NETs) and pituitary, adrenal, bronchial, and thymic (thNET) tumors and the presence of metastasis. Intrafamilial correlations and heritability estimates were calculated from family tree data using specific validated statistical analysis software.

RESULTS

Intrafamilial correlations were significant and decreased along parental degrees distance for pituitary, adrenal and thNETs. The heritability of these three tumor types was consistently strong and significant with 64% (s.e.m.=0.13; P<0.001) for pituitary tumor, 65% (s.e.m.=0.21; P<0.001) for adrenal tumors, and 97% (s.e.m.=0.41; P=0.006) for thNETs.

CONCLUSION

The present study shows the existence of modifying genetic factors for thymus, adrenal, and pituitary MEN1 tumor types. The identification of at-risk subgroups of individuals within cohorts is the first step toward personalization of care. Next generation sequencing on this subset of tumors will help identify the molecular basis of MEN1 variable genetic expressivity.

Gender-related differences in MEN1 lesion occurrence and diagnosis: a cohort study of 734 cases from the Groupe d'etude des Tumeurs Endocrines

CONTEXT

Multiple endocrine neoplasia type 1 (MEN1) disease is an autosomal dominant syndrome that is believed to equally affect men and women. This assumption has never been confirmed.

OBJECTIVE

The aims of this study were to evaluate the impact of gender on the prevalence of MEN1 lesions, on their lifetime probability of occurrence, and on the diagnosis of MEN1.

DESIGN

Data regarding a study of 734 cases of MEN1 from the multicenter 'Groupe d'étude des Tumeurs Endocrines' were analyzed.

RESULTS

There were 57.8% females. The prevalence and probability of pancreatic tumors were higher in males than in females (P=0.06, P=0.0004). This difference was due to gastrinomas. The prevalence and probability of developing pituitary tumors were significantly greater in females (P<0.001, P<0.0001). Thymic tumors were exclusively found in men. There were no significant gender differences in the prevalence and the probability of developing hyperparathyroidism, or adrenal and bronchial tumors, or in the proportion of positive genetic tests. A family history of MEN1 was more frequently found in men than in women at the time of diagnosis (P=0.02). In the case of pituitary tumor, the proportion of patients diagnosed with MEN1 at the time of the first lesion was lower in women (44.2%) than in men (67.3%).

CONCLUSION

The phenotype expression of the MEN1 disease gene was different in males and females. In female patients, the possibility of MEN1 is not sufficiently taken into account. Any patient presenting a lesion that belongs to the MEN1 spectrum, such as a pituitary tumor, should be closely questioned about their family history and should be tested for hypercalcemia.

Technical risks with subcutaneous insulin infusion

The popularity of continuous subcutaneous insulin infusion (CSII), as a way for achieving long term strict glycaemic control in diabetic patients, has increased over the last ten years. Most reports on technical faults, often leading to metabolic emergencies, mainly ketoacidosis, have been published in the 1980s. Obstruction of infusion set and infection of infusion site are the most frequent events. Insulin precipitation or aggregation is thought to be one of the precipitating factors. Few data are available about failures of the pump itself. We report our experience of pump malfunctions recorded between 2001 and 2004 in 376 pumps used by patients treated with CSII therapy in Brittany. Recent studies indicate a decrease of metabolic complication frequency during CSII. This suggests technical improvements and/or a greater experience of physicians in selecting and educating patients. We report instructions for monitoring insulin pump therapy that should be included in a formal educational program for pump users. Clinical studies using newly available devices should reassess technical risks associated with CSII.

[Anti-TPO antibodies and screening of thyroid dysfunction in type 1 diabetic patients]

The diagnosis of thyroid dysfunction is often late in type 1 diabetic population. So, the aims of this study were 1) to evaluate the prevalences of thyroperoxydase (TPO) and thyroglobulin (Tg) autoantibodies detected by highly sensitive radioimmunological method in a cohort of 258 adult type 1 diabetic patients without evidence of clinical thyroid disease; 2) to determine whether or not measurement of TPO and/or Tg antibodies can identify subjects at risk of clinical or infraclinical thyroid dysfunction by measuring TSH in the entire group. TPO antibodies were found in 45 of the 258 diabetic patients (17%). The prevalence of TPO antibodies was not influenced by the following factors: gender, duration of disease, age at screening and at diabetes diagnosis, positivity of familial history. Tg antibodies were found in 19 patients (7%), including 13 cases with TPO antibodies. All patients without TPO antibody (n=213), including Tg-positive patients displayed TSH values in normal range. Among the 45 TPO-positive patients, 11 patients displayed infraclinical thyroid dysfunction. At the end of the 5-year follow-up, only 2/45 patients became anti-TPO negative. Thirteen of the 45 patients developed subclinical or clinical thyroid diseases (4 Graves'disease and 9 thyroiditis with hypothyroidism). By contrast, none of 45 TPO negative patients, sex and age matched with the TPO-positive patients, developed during follow-up anti-TPO positivity and/or infraclinical thyroid dysfunction. In conclusion, the determination of TPO antibodies by a highly sensitive method allows identifying diabetic patients with thyroid autoimmunity and at risk of subsequent impaired thyroid function, whatever age at diagnosis and diabetes duration. By contrast, anti-Tg determination did not give further information about subsequent thyroid dysfunction. In TPO antibody positive patients repeated thyroid clinical examination and TSH determination could be recommended to detect infraclinical thyroid dysfunction.

Antithyroid drugs and Graves' disease--prospective randomized assessment of long-term treatment

OBJECTIVE

Although antithyroid drugs (ATD) are widely used in the treatment of Graves' disease, management protocols, especially treatment duration, remain a subject of debate. The rate of relapse after short-term regimens of less than 6 months with ATD at decreasing doses is higher than after longer treatments from 12 to 24 months. As no prospective study has provided data on even longer protocols exceeding 2 years, we conducted a prospective trial to determine potential benefits of a 42-month treatment compared with an 18-month treatment.

DESIGN, PATIENTS AND MEASUREMENTS

The aim of this prospective randomized trial was to compare relapse rates achieved two years after treatment withdrawal in patients who received carbimazole at decreasing doses for 18 months (n = 62) vs 42 months (n = 72). In addition to clinical relapse rate, the percentage of patients who normalized antithyroperoxidase (TPO) antibody and anti-TSH receptor stimulating antibody (TSAb) levels and early iodine uptake at the end of treatment were assessed as outcome criteria.

RESULTS

The relapse rate two years after discontinuation of treatment did not differ significantly in patients treated for 18 months from those treated for 42 months (36% vs 29%, NS). At the end of treatment, there was no significant difference between the two groups in the percentage of anti-TPO positive patients (53% vs 46%, NS) or early iodine uptake (27% vs 21%, NS). Although the percentage of patients with TSAb was significantly lower in the 42-month treatment group (18% vs 42%, P = 0.004) at treatment withdrawal, the percentage of TSAb-positive patients did not significantly decrease between 18 and 42 months in this group (27% vs 18%, NS).

CONCLUSION

Treatment duration greater than 18 months did not improve remission rate determined 2 years after treatment withdrawal or immunological variables or early iodine uptake measured at the time of discontinuation of treatment. These findings would indicate that, when a defined duration treatment is planned, prolonging treatment beyond 18 months does not provide any additional benefit.

Clinical and statistical evaluation of self-monitoring blood glucose meters

OBJECTIVE

Our objective was to compare statistical and clinical methods for the evaluation of five self-monitoring blood glucose (SMBG) meters.

RESEARCH DESIGN AND METHODS

Two successive capillary blood glucose measurements were performed, and a simultaneous laboratory venous glucose measurement was used as the reference value. Accuracy was studied by comparing each of the two successive meter values with the reference value by 1) a Spearman's correlation test, 2) a Wilcoxon's paired test, 3) the percentage of values within the 10% interval of the reference value according to the American Diabetes Association consensus statement, and 4) the error grid analysis.

RESULTS

The first two methods did not discriminate between the SMBG systems: r was >0.92 for the five meters, and a significant difference between the meter and reference values was found for all but one meter. The two other methods allowed classification of the devices into three groups according to their accuracy: good (two meters), acceptable (two meters), and unacceptable (one meter). These two methods gave consistent results and both had a good reproducibility, because the classification was similar for the two successive measurements.

CONCLUSIONS

Both the Spearman's and Wilcoxon's paired tests, although commonly used, are inappropriate to evaluate SMBG systems. The percentage of SMBG values within the +/-10% interval and the error grid analysis are more accurate, because they consistently classified the five glucose meters tested in our study with a high degree of reproducibility.

[Early therapeutic management of patients genetically predisposed to medullary thyroid cancer]

STUDY

The aim of our study was to study therapeutic results after thyroidectomy in patients positive for predictive genetic analysis and with preoperative calcitonin (CT) response to pentagastlin (Pg) < 150 pg/ml.

MATERIAL AND METHODS

36 patients (13 F, 23 M) were selected: 13 F-MTC from 8 families, 22 MEN 2A from 15 families and 1 MEN 2B. They were positive for direct RET mutation analysis. CT was assayed by immunoradiometric method before and after Pg. Pg test results before and after thyroidectomy, age at operation and histologic results were analysed.

RESULTS

Mean preoperative peak CT was 82.5 +/- 34.0 pg/ml (22-133): among these 36 patients preoperative basal and peak CT were normal in 16 and 2 patients respectively. F-MTC and MEN 2A patients were different according to their preoperative peak CT levels (58.1 +/- 24.0 vs 97.6 +/- 31.3) pg/ml, p < 0.01) and age at thyroidectomy (20.4 +/- 10.5 vs 11.6 +/- 7.6 years, p < 0.01 by Mann-Whitney test). Total thyroidectomy was performed in all patients at a mean age of 14.8 +/- 9.8 years (2.5-41.7) and was associated with lymph node dissection in 30 cases. The 2 F-MTC patients with normal preoperative peak CT levels had bilateral C-cell hyperplasia (CCH) associated with uni or bilateral micro-MTC. Other patients had uni or bilateral micro MTC except 4 who had isolated CCH without carcinoma. The age of two MEN-2A and 1 MEN 2B patients with micro-MTC ranged from 2.5 to 4.7 yr. Micro MTC was present in 100% of MEN-2A cases after the age of 10 yr. There were no lymph nodes metastases. During postoperative survey, the last PG tests (n = 33) were performed 27.5 months (1-92) after thyroidectomy: peak CT values were always < 10 pg/ml.

IN CONCLUSION

Thyroidectomy should be performed at a very young age in RET mutation carriers, regardless of the plasma CT values. This choice is justified in NEM-2A and NEM-2B patients but must be discussed in F-MTC families with less aggressive forms of the disease.

[Primary adrenal lymphoma with latent adrenal insufficiency: a case report and literature review]

We report a new case of primary adrenal lymphoma with latent adrenal insufficiency and long-term remission after hydrocortisone replacement therapy. We have analyzed 29 other cases described in the literature. This disease with poor prognosis can be revealed by an incidentally discovered, frequently bilateral, adrenal mass. Adrenal insufficiency may be latent and the diagnostic procedure should include both cortisol and ACTH determination with an additional ACTH stimulation test if appropriate. Early adrenal substitution can improve patient survival.

Prognostic factors for survival and for biochemical cure in medullary thyroid carcinoma: results in 899 patients. The GETC Study Group. Groupe d'étude des tumeurs à calcitonine

BACKGROUND

Prognostic factors of sporadic or inherited medullary thyroid carcinoma (MTC) are still controversial and have been assessed in old and small series. A better knowledge of these factors would improve patient management.

OBJECTIVE

To evaluate factors involved in the prognosis of MTC in a large series of cases, using uni- and multivariate analysis.

DESIGN AND PATIENTS

Clinical, biological, surgical and epidemiological data on 899 MTC patients, diagnosed between 1952 and 1996, were collected by the French Calcitonin Tumors Study Group (GETC) with a standardized questionnaire, and processed in a national database.

MEASUREMENTS

Survival and biochemical cure (i.e. normal basal post-operative serum calcitonin levels) were analysed with Kaplan and Meier and log-rank test statistical procedures. Data are presented as adjusted rather than observed survival, to consider only patients who died of MTC. Cox's forward-stepping proportional hazard model was used to analyse factors with a significant influence on survival by univariate analysis.

RESULTS

Apart from the large proportion of familial forms (43%), the general characteristics of our population were similar to those in other studies: mean age at surgery = 43.4 years; sex ratio = 1 male/1.35 female; stage I = 20.8%; stage II = 21.2%; stage III = 46.5% and stage IV = 11.5%. 863 (96%) patients underwent surgery; 43% of operated patients were biochemically cured. Adjusted survival was 85.7 +/- 1.5% at 5 years and 78.4 +/- 2.1% at 10 years. Multivariate analysis showed that age and stage were independent predictive factors of survival. Gender, type of surgery, type of familial form were predictive only in univariate analysis. Biochemical cure predicts a survival rate of 97.7% at 10 years. Authentic recurrence, that is subsequent elevation of calcitonin (CT) after post-operative normalization, was found in 4.9%. In non-cured patients (57%), survival was still good: 80.2% (+/- 2.2%) and 70.3% (+/- 2.9%) at 5 and 10 years, respectively. Similarly, prediction of biochemical cure was solely dependent on stage.

CONCLUSION

Survival of these medullary thyroid carcinoma patients appears better than expected even in non-cured patients. Considering the strong impact of stage, the necessity for pre-operative diagnosis of MTC is obvious.

Anti-pancreatic autoimmunity and Graves' disease: study of a cohort of 600 Caucasian patients

The aim of this study was to investigate the frequencies of clinical diabetes and humoral markers of anti-pancreatic autoimmunity in a homogeneous population of 600 Caucasian patients with recently diagnosed Graves' disease (GD), in order to characterize the specific features of this group of endocrine patients among subjects at risk of diabetes. Ten were already diabetic at GD diagnosis. Among the 590 non-diabetic patients, 29 had islet cell antibodies (ICA), including 15 with low titre ICA and only 1 ICA-positive subject with a familial history of diabetes. Twenty-four patients had insulin autoantibodies, including three in association with ICA. Glutamic acid decarboxylase (GAD)/64 kDa antibodies were found in 16 of the 150 tested sera, including 13 of the 29 ICA-positive sera. Four ICA-positive patients displayed 37/40 kDa antibodies, including three in association with GAD/64 kDa antibodies. During follow-up, one of the ICA-positive patients developed insulin-dependent diabetes, 14 years after the GD diagnosis. To summarize, this anti-pancreatic autoimmunity study was focused on a large but specific and homogeneous group of subjects at risk for diabetes: recently diagnosed GD patients. This population was characterized by a high prevalence of GAD/64 kDa antibodies but also by a low frequency of evolution towards diabetes and the slowness of the process which could be due to the fact that only a minority of subjects possessed a sufficient combination of anti-pancreatic markers at the same time.

Increased prevalence of thyroid autoantibodies and subclinical thyroid failure in relatives of patients with overt endocrine disease-associated diabetes but not type 1 diabetes alone

The purpose of this study was to determine the prevalence of thyroperoxidase (TPO) and thyroglobulin (Tg) antibodies, using a sensitive and specific radioimmunoassay method in a large cohort of 254 first-degree relatives of Type 1 diabetic patients with or without other autoimmune endocrinopathy, and to evaluate the predictive value of thyroid antibodies for impaired thyroid function in these groups. TPO and Tg antibodies were found at similar frequencies (12%) in the 254 relatives, and both antibodies were present in 23 cases (9%). Seven subjects displayed subclinical thyroid dysfunction without an abnormal free T4 level. Among first-degree relatives of probands with Type 1 diabetes alone, TPO or Tg antibodies were found in 8 subjects (6%), including 6 with both antibodies. The prevalence of TPO antibodies was significantly greater among relatives of TPO-positive than TPO-negative probands (p < 0.01). In relatives of diabetic patients with other endocrinopathy, frequencies of TPO (20%), Tg (19%) and a combination of both antibodies (15%) were significantly higher than in relatives of Type 1 diabetic patients without endocrinopathy (p < 0.001). TSH levels were abnormal in only one relative of the group without endocrinopathy but occurred in 6 relatives of the proband with overt endocrinopathy-associated diabetes (p < 0.02) in marked association with TPO antibodies (p < 10(-4). It is concluded that relatives of probands with overt endocrine autoimmune disease-associated diabetes, unlike those of probands with diabetes alone, showed increased prevalence of thyroid antibodies and thyroid dysfunction. These results argue for a different risk of thyroid autoimmunity and clinical disease in families of diabetic patients without or with overt endocrine disease. A screening of thyroid autoimmunity is highly recommended for the latter group.

Genetic heterogeneity between type 1a and type 1b insulin-dependent diabetes mellitus: HLA class II and TAP gene analysis

The aim of this study was to compare the genetic susceptibility linked to the HLA Class II region genes of the Major Histocompatibility Complex in isolated insulin-dependent diabetes mellitus (1a-IDDM) and insulin-dependent diabetes mellitus associated with another autoimmune endocrinopathy (1b-IDDM). HLA genes DRB1, DQA1 and DQB1 were studied at the genomic level, as well as genes TAP1 and TAP2. One hundred and seventy-nine 1a-IDDM diabetic patients were compared with 83 1b-IDDM patients. While it appeared that common genetic traits characterize diabetes regardless of the subtype (1a or 1b), certain features differentiate the two forms of IDDM. Extending the analysis of risk haplotypes DRB1*03 and DRB1*04 to TAP genes elicited a difference between 1a-IDDM and 1b-IDDM patients. Haplo-type DRB1*03 was thus characterized in 1a-IDDM patients by a lower frequency of alleles TAP1-B (13.5%) and TAP2-B (16.2%), not found in 1b-IDDM patients (33.3% for each allele). Likewise, haplotype DRB1*04 is characterized in 1b-IDDM patients by a lower frequency of alleles TAP1-C (4.0%) and TAP2-B (8.0%) than in 1a-IDDM patients (22.2% and 25.9%, respectively). In total, this study showed that extending the characterization of HLA Class II haplotypes to TAP genes discriminates between the forms of diabetes restricted to a specific pancreatic affection and those reflecting a wider autoimmune disorder affecting several organs.

Differential beta-cell response to glucose, glucagon, and arginine during progression to type I (insulin-dependent) diabetes mellitus

Acute insulin responses to glucose (AIRG), glucagon (AIRGln), and arginine (AIRArg) were evaluated prospectively in nine subjects positive for islet-cell antibodies (ICAs) who later progressed to type I diabetes or impaired glucose tolerance (IGT) (progressors), 64 ICA-positive subjects at risk who did not develop type I diabetes, 365 ICA-negative relatives of diabetic patients who also remained free of the disease, and 89 control subjects. Seven progressors already had a low AIRG at entry into the study, and the other two became low responders 3 to 9 months before diabetes or IGT, with a progressive decline of AIRG over serial intravenous (IV) glucose tolerance tests. At entry into the study, the group of progressors displayed lower AIRG, AIRGln, and AIRArg than the other three groups (P<.001). However, AIRArg was less altered than AIRG. During the course of the prediabetic phase, there was a progressive decline in AIRG and AIRGln analyzed as a function either of time (P<.006) or of basal glycemia (P<.05), ie, two different ways of estimating worsening of the disease process. Conversely, there was no significant decrease in AIRArg with time or with increasing basal glycemia, so that AIRArg was not totally blunted in these prediabetic subjects even a few months before the onset of diabetes. The persistence of a substantial response to arginine, ie, higher than the fifth control percentile, even at a late stage, was confirmed in five of nine diabetic patients tested either at onset of the disease or during non-insulin-receiving remission. Whereas AIRG deteriorates during prediabetes, AIRArg appears to be less altered with time and increased basal glycemia, remaining substantial even at the onset of the disease. This reinforces the supposition that the prediabetic state may be associated with a glucose-specific beta-cell functional abnormality in addition to a decreasing beta-cell mass.

Pheochromocytoma and secondary erythrocytosis: role of tumour erythropoietin secretion

Certain neoplasias can induce unregulated erythropoietin (EPO) secretion which results in secondary erythrocytosis. Pheochromocytoma associated with erythrocytosis constitute a rare condition, where the secondary red cell abnormality is believed to be due to tumour EPO secretion. In one such case of pheochromocytoma related erythrocytosis, quantitative determination of serum EPO by enzyme immunoassay was combined with immunohistochemical examination of tumour tissue sections to locate the site of EPO secretion. EPO levels were initially high but decreased after tumour surgery, while immunolocalization showed EPO to be secreted by the neoplastic cells.

Comparative effects of 6 week fructose, dextrose and starch feeding on fat-cell lipolysis in normal rats: effects of isoproterenol, theophylline and insulin

The precise effects of fructose feeding on adipose tissue is not clearly known. Consequently, we studied the effects of fructose feeding on stimulated and inhibited in vitro lipolysis. Twenty seven male Sprague Dawley rats, 5 weeks of age, were fed for 6 weeks on one of three diets containing 57% CHO as fructose (F), dextrose (D) or starch (S). At week 6 the epididymal fat pad weights showed no difference between groups. Stimulation of lipolysis by isoproterenol or theophylline showed: decreased sensitivity of adipocytes to isoproterenol, but not to theophylline, in F (p less than 0.05); the maximal responses were decreased, but NS, after stimulation by either isoproterenol or theophylline. The maximal antilipolytic responses to insulin were increased in F (27%) and D (29%) when compared to S (16%), (p less than 0.05). Only, in F there was an increase (NS) in ED50 (0.63 +/- 0.23 ng/ml) compared to D (0.45 +/- 0.18) and S (0.29 +/- 0.18), indicating decreased sensitivity. Nonfasting plasma insulin and triglycerides were increased at the 6th week in F (p less than 0.01), without any change in plasma glucose levels. However, there was no difference in 12 h fasting plasma glucose, insulin or triglycerides. In conclusion, a 6 week 57% fructose containing diet in normal rats led to: 1) decreased lipid mobilization in the epididymal adipose tissue; and 2) increased nonfasting plasma insulin and triglycerides. Thus fructose, under these experimental conditions, seems to have adverse metabolic effects in normal rats.

Comparison of thyroperoxidase and microsomal antibody assays in sera from patients with Graves disease

Anti-microsomal (anti-Mic Ab) and anti-thyroperoxidase antibody activities (anti-TPO Ab) were compared by using commercially available radioassay kits. Sera were collected from 52 patients with Graves disease before and after administration of carbimazole (1-methyl-2-thio-3-carbethoxyimidazole). The two antibody concentrations were significantly correlated, both before treatment (r = 0.835, P less than 0.001, n = 52) and at the end of treatment (r = 0.584, P less than 0.001, n = 52). Twenty-nine (Group I) of the 52 patients were in remission for two years after drug withdrawal, whereas 23 (Group II) relapsed. Within each group, the anti-Mic and anti-TPO Ab concentrations were significantly correlated (Group I: r = 0.781, P less than 0.0001; Group II: r = 0.866, P less than 0.0001). Relapse vs nonrelapse was linked to the antibody positivities measured before treatment: 91% vs 65% (chi 2 = 4.75, P less than 0.02) for anti-Mic Ab and 87% vs 62% (chi 2 = 4.05, P less than 0.02) for anti-TPO Ab. We conclude that assays of anti-Mic and anti-TPO Ab are equally reliable analytically and equally informative clinically. Because of its rapid implementation, the anti-TPO assay may advantageously replace anti-Mic Ab assay, especially for forming a prognosis of Graves disease.

Comparison of thyroperoxidase and microsomal antibody assays in sera from patients with Graves disease

Anti-microsomal (anti-Mic Ab) and anti-thyroperoxidase antibody activities (anti-TPO Ab) were compared by using commercially available radioassay kits. Sera were collected from 52 patients with Graves disease before and after administration of carbimazole (1-methyl-2-thio-3-carbethoxyimidazole). The two antibody concentrations were significantly correlated, both before treatment (r = 0.835, P less than 0.001, n = 52) and at the end of treatment (r = 0.584, P less than 0.001, n = 52). Twenty-nine (Group I) of the 52 patients were in remission for two years after drug withdrawal, whereas 23 (Group II) relapsed. Within each group, the anti-Mic and anti-TPO Ab concentrations were significantly correlated (Group I: r = 0.781, P less than 0.0001; Group II: r = 0.866, P less than 0.0001). Relapse vs nonrelapse was linked to the antibody positivities measured before treatment: 91% vs 65% (chi 2 = 4.75, P less than 0.02) for anti-Mic Ab and 87% vs 62% (chi 2 = 4.05, P less than 0.02) for anti-TPO Ab. We conclude that assays of anti-Mic and anti-TPO Ab are equally reliable analytically and equally informative clinically. Because of its rapid implementation, the anti-TPO assay may advantageously replace anti-Mic Ab assay, especially for forming a prognosis of Graves disease.