Correction to: EStradiol and PRogesterone in In vitro ferTilization (ESPRIT): a multicenter study evaluating third­ versus second­generation estradiol and progesterone immunoassays.

The article "EStradiol and PRogesterone in In vitro ferTilization (ESPRIT): a multicenter study evaluating third­ versus second­generation estradiol and progesterone immunoassays.

EStradiol and PRogesterone in In vitro ferTilization (ESPRIT): a multicenter study evaluating third- versus second-generation estradiol and progesterone immunoassays.

PURPOSE: To assess estradiol (E2) and progesterone levels during ovarian stimulation determined by third-generation (Gen III) and second-generation (Gen II) Elecsys® immunoassays. METHODS: E2 and progesterone concentrations were measured using Elecsys® Gen III and Gen II immunoassays, and progesterone concentrations on the day of ovulation triggering were determined by LC-MS/MS. This was a retrospective, non-interventional study conducted at European tertiary referral infertility clinics in women aged 18-45 years, with a body mass index 18-35 kg/m2, regular menses, and both ovaries. RESULTS: Serum samples were obtained from 230 women classified by oocyte retrieval as poor (33.0%; 0-3 oocytes), normal (40.9%; 4-15 oocytes), or high (26.1%; > 15 oocytes) responders. E2 and progesterone levels increased during ovarian stimulation, with greatest increases observed in high responders. Elecsys® Gen III and Gen II assay results were highly correlated for E2 (Pearson's r = 0.99) and progesterone (r = 0.89); Gen III results were lower than Gen II for both E2 and progesterone. On the day of triggering, Gen III E2 and progesterone levels showed a difference of - 15.0% and - 27.9%, respectively. Progesterone levels (on day of triggering) measured by LC-MS/MS correlated better with Gen III (0.98) than Gen II (0.90). Mean relative differences for Gen III and Gen II assays versus LC-MS/MS were 14.6% and 62.8%, respectively. CONCLUSION: E2 and progesterone levels determined with Elecsys® Gen II and III assays were highly correlated; results were lower for Gen III versus Gen II. Differences observed for progesterone on the day of triggering may be clinically relevant.

IDDM patients neither show humoral reactivities against endogenous retroviral envelope protein nor do they differ in retroviral mRNA expression from healthy relatives or normal individuals.

Recently, human endogenous retrovirus type K (HERV-K [IDDMK(1,2)22]) was isolated from an IDDM patient's beta-cell supernatant and shown to be implicated in expression as a superantigen. Furthermore, HERV-K RNA was found in plasma samples from newly diagnosed patients but not in those from healthy control subjects. We had earlier identified the presence of a HERV-K long terminal repeat element of the HLA DQ gene (DQ-LTR) to be positively associated with IDDM, which led us to investigate whether DQ-LTR is related to transcription of the putative retroviral superantigen. Additionally, we sought immunological evidence to determine whether those retroviral antigens could evoke an antibody response. Patients with IDDM (n = 14), Hashimoto's thyroiditits (n = 5), and Graves' disease (n = 12), as well as healthy control subjects (n = 12), were investigated, as were four nuclear families of Graves' disease patients and two of IDDM patients. RNA was isolated from plasma and peripheral blood lymphocytes and subjected to reverse transcription-polymerase chain reaction for transcripts of the env region of the HERV-K (IDDMK(1,2)22) sequence. We identified env transcripts in both plasma and peripheral blood lymphocytes in all individuals studied: patients with recent-onset or long-standing IDDM, their relatives, and healthy control subjects, as well as patients with thyroid autoimmune disorders. Furthermore, we screened the sera of patients (n = 62) and control subjects (n = 35) for evidence of humoral immunity against HERV-K by Western blot specific for the ENV protein. Similar frequencies of antibody-positives were observed both in patients with IDDM (29%) and in healthy control subjects (26%). We conclude that neither the ubiquitous HERV-K transcripts nor the comparable percentage of ENV protein antibodies are associated with IDDM. An earlier, presymptomatic antibody response against HERV-K (IDDMK(1,22)22) ENV cannot be ruled out. However, the superantigen hypothesis of an endogenous retrovirus in beta-cell autoimmunity awaits confirmation.

Vitamin D receptor allele combinations influence genetic susceptibility to type 1 diabetes in Germans.

Vitamin D has been shown to exert manifold immunomodulatory effects. Because type 1 diabetes is regarded to be immune-mediated and vitamin D prevents the development of diabetes in the NOD mouse, we investigated the role of the vitamin D receptor (VDR) gene as a candidate for type 1 diabetes susceptibility. A total of 152 Caucasian families with at least one affected offspring were genotyped for four VDR restriction-site polymorphisms (FokI, BsmI, ApaI, and TaqI). Whereas the BsmI, ApaI, and TaqI polymorphisms are in strong linkage disequilibrium with each other, no significant linkage disequilibrium with the FokI site was observed. Extended transmission disequilibrium testing (ETDT) was used to detect preferential transmission of allelic combinations to affected offspring. We found significant haplotype-wise ETDT results for the BsmI/ApaI/TaqI (chi2 = 18.886, df = 7, P = 0.0086), the BsmI/TaqI (chi2 = 8.373, df = 3, P = 0.0389), and theApaI/TaqI (chi2 = 17.182, df = 3, P = 0.0006) haplotypes. The "At" and "Bt" alleles confer an increased risk, whereas "AT" and "at" are protective. The combination with the strongest susceptibility was the "BAt" haplotype (64% transmitted, P = 0.0106). Analysis of the FokI site does not provide more information on susceptibility (FokI/BsmI/ApaI/TaqI [chi2 = 24.702, df = 15, P = 0.0541]). These findings suggest a linkage of VDR itself or a nearby gene with type 1 diabetes susceptibility in Germans, confirming respective observations previously made in Indian Asians.

The codon 17 polymorphism of the CTLA4 gene in type 2 diabetes mellitus.

Several studies have demonstrated an association of CTLA4 (IDDM12) alanine-17 with type 1 diabetes, but CTLA4 variants have not yet been investigated in type 2 diabetes. The CTLA4 exon 1 polymorphism (49 A/G) was analyzed in 300 Caucasian patients with type 2 diabetes and 466 healthy controls. All patients were negative for glutamate decarboxylase and islet cell antibodies. CTLA4 alleles were defined by PCR, single-strand conformational polymorphism, and restriction length fragment polymorphism analysis using BBV:I. The distribution of alleles as well as the genotypic and phenotypic frequencies were similar among patients and controls [AA, 42 vs. 39%; AG, 47 vs. 46%; GG, 11 vs. 15%, P = not significant (n.s.); A/G, 65/35% vs. 62/38%, P = n.s.; alanine/threonine 92/58% vs. 85/61%, P = n.s.]. However, detailed analysis of clinical and biochemical parameters revealed a tendency of GG (alanine/alanine) toward younger age at disease manifestation (46.8 +/- 0.8 vs. 49.5 +/- 0.8 yr, mean +/- SEM), lower body mass index (21.4 +/- 0.5 vs. 24.4 +/- 0.5 kg/m(2), P = 0.042), and basal C-peptide level (0.33 +/- 0.07 vs. 0.53 +/- 0.07nmol/L), as well as earlier start of insulin treatment (5.8 +/- 1.2 vs. 8.7 +/- 0.6 yr) and higher portion of patients on insulin (71 vs. 61%). Patients with the AA genotype were significantly less likely to develop microangiopathic lesions (P < 0.0005). No differences were found for hypertension or family history of type 2 diabetes. In conclusion, CTLA4 alanine-17 does not represent a major risk factor for type 2 diabetes. Additional studies on larger groups and different ethnic groups are warranted to clarify the association of the GG genotype with faster ss-cell failure and the lower rate of microvascular complications in AA carriers.

Codon 17 polymorphism of the cytotoxic T lymphocyte antigen 4 gene in Hashimoto's thyroiditis and Addison's disease.

Endocrine autoimmune disorders share susceptibility and resistance factors of the human leukocyte antigen system on the short arm of chromosome 6, but other gene loci also contribute to predisposition and protection. Because the cytotoxic T lymphocyte antigen 4 (CTLA4) alanine-17 encoded by the CTLA4 gene on chromosome 2q33 confers susceptibility to Graves' disease, as well as to type 1 (insulin-dependent) diabetes mellitus, we investigated this dimorphism in the other endocrine autoimmune disorders: Hashimoto's thyroiditis and Addison's disease. We analyzed the CTLA4 exon 1 polymorphism (49 A/G) in 73 patients with Hashimoto's thyroiditis, 76 with Addison's disease, and 466 healthy controls. This dimorphism corresponds to an aminoacid exchange (Thr/Ala) in the leader peptide of the expressed protein. CTLA4 alleles were defined by PCR, single-strand conformational polymorphism analysis, and restriction fragment length polymorphism analysis using BbvI. Patients with Hashimoto's thyroiditis had significantly more Ala alleles than controls, both as homozygotes (22% vs. 15%) and heterozygotes (53% vs. 46%), and less Thr than controls as homozygotes (25% vs. 39%), P < 0.04. The phenotypic frequency for Ala was significantly higher in patients (75%), compared with controls (61%), P < 0.03. Patients with Addison's disease did not differ significantly from controls, but those carrying the suceptibility marker, human leukocyte antigen DQA1*0501, were significantly more CTLA4 Ala17 positive than controls with the same DQA1 allele (P < 0.05). In conclusion, an alanine at codon 17 of CTLA4 confers genetic susceptibility to Hashimoto's thyroiditis, whereas this applies only to the subgroup of DQA1*0501+ patients with Addison's disease.

CTLA4 alanine-17 confers genetic susceptibility to Graves' disease and to type 1 diabetes mellitus.

The genetic susceptibility to Graves' disease and type 1 (insulin-dependent) diabetes mellitus is conferred by genes in the human leukocyte antigen region on the short arm of chromosome 6, but several other genes are presumed to determine disease susceptibility. Among those candidate genes is the cytotoxic T lymphocyte antigen 4 (CTLA4) located on chromosome 2q33 in man. We investigated the distribution of the CTLA4 exon 1 polymorphism (49 A/G) in Graves' disease and IDDM. This dimorphism at codon 17 results in an amino acid exchange (Thr/Ala) in the leader peptide of the expressed protein and was analyzed by PCR, single strand conformation polymorphism, and restriction fragment length polymorphism analysis in 305 patients with Graves' disease, 293 patients with IDDM, and 325 controls. Patients with Graves' disease had significantly more Ala alleles than controls, both as homozygotes (21% vs. 13%) and as heterozygotes (53% vs. 46%), and less Thr as homozygotes (26% vs. 42%; P < 2 x 10(-4). The phenotypic frequency of Ala-positive patients (73%) was significantly higher than of controls (58%; P = 10(-4); relative risk = 2). Patients with IDDM also had significantly more Ala alleles as homozygotes (19%) or heterozygotes (50%; P = 0.01). In conclusion, an alanine at codon 17 of CTLA4 is associated with genetic susceptibility to Graves' disease as well as to IDDM.

The presence or absence of a retroviral long terminal repeat influences the genetic risk for type 1 diabetes conferred by human leukocyte antigen DQ haplotypes. Belgian Diabetes Registry.

Major genetic susceptibility to type 1 diabetes mellitus maps to the human leukocyte antigen (HLA) region on chromosome 6p. During evolution, endogenous retroviral long terminal repeats (LTR) have been integrated at several sites within this region. We analyzed the presence of a solitary HERV-K LTR in the HLA DQ region (DQ-LTR3) and its linkage to DRB1, DQA1, and DQB1 haplotypes derived from 246 German and Belgian families with a patient suffering from type 1 diabetes mellitus. Segregation analysis of 984 HLA DQA1/B1 haplotypes showed that DQ-LTR3 is linked to distinct DQA1 and DQB1 haplotypes but is absent in others. The presence of DQ-LTR3 on HLA DQB1*0302 haplotypes was preferentially transmitted to patients from heterozygous parents (82%; P < 10(-6)), in contrast to only 2 of 7 DQB1*0302 haplotypes without DQ-LTR3. Also, the extended HLA DRB1*0401, DQB1*0302 DQ-LTR3-positive haplotypes were preferentially transmitted (84%; P < 10(-6)) compared with 1 of 6 DR-DQ matched DQ-LTR3 negative haplotypes. DQ-LTR3 is missing on most DQB1*0201 haplotypes, and those LTR3 negative haplotypes were also preferentially transmitted to patients (80%; P < 10(-6)), whereas DQB1*0201 DQ-LTR3-positive haplotypes were less often transmitted to patients (36%). Other DQA1/B1 haplotypes did not differ for DQ-LTR3 between transmitted and nontransmitted haplotypes. Thus, the presence of DQLTR3 on HLA DQB1*0302 and its absence on DQB1*0201 haplotypes are independent genetic risk markers for type 1 diabetes.

The electrocardiogram at rest and exercise during a simulated ascent of Mt. Everest (Operation Everest II).

To evaluate the effect of extreme altitude on cardiac function in normal young men, electrocardiograms were recorded at rest and during maximal exercise at several simulated altitudes up to the equivalent of the summit of Mt. Everest (240 torr or 8,848 m). The subjects spent 40 days in a hypobaric chamber as the pressure was gradually reduced to simulate an ascent. Changes in the resting electrocardiogram were evident at 483 torr (3,660 m) and were more marked at 282 torr (7,620 m) and 240 torr (8,848 m). They consisted of an increase in resting heart rate from 63 +/- 5 to a maximum of 89 +/- 8 beats/min; increase in P-wave amplitude in inferior leads; right-axis shift in the frontal plane; increased S/R ratio in the left precordial leads; and increased T negativity in V1 and V2. No significant arrhythmias or conduction defects were observed. Most changes reverted to normal within 12 hours of return to sea level, with the exception of the frontal-plane axis and T-wave alterations. Maximal cycle ergometer exercise at 282 torr (7,620 m) and 240 torr (8,848 m) resulted in a heart rate of 138 +/- 7 and 119 +/- 6 beats/min at the 2 altitudes, respectively. No ST depression or T-wave changes suggestive of ischemia occurred despite a mean arterial oxygen saturation of 49% and a mean pH of 8 during peak exercise. Occasional ventricular premature beats were observed during exercise in 2 subjects.(ABSTRACT TRUNCATED AT 250 WORDS)

An endogenous retroviral long terminal repeat at the HLA-DQB1 gene locus confers susceptibility to rheumatoid arthritis.

Human endogenous retrovirus (HERV) long terminal repeat (LTR) elements contain regulatory sequences that can influence the expression of adjacent cellular genes, which may contribute to breakdowns of the immune function leading to autoimmune disease. Rheumatoid arthritis (RA) is associated with particular HLA-DR/DQ haplotypes that modulate the pathogenesis of this autoimmune disease. We have therefore studied a solitary LTR element (DQ-LTR3) of the HERV-K family at the HLA-DQB1 locus for a possible disease association among 228 RA patients and 311 unrelated blood donors. The DQ-LTR3 was significantly more frequent among patients (76% vs 33%, OR = 5.07,p < 0.0001), with the majority of patients being heterozygous for the DQ-LTR3 (61% vs 22%, p < 0.0001). HLA-DRB1*04 positive patients did still differ for the presence of the DQ-LTR3 (88% vs 70%, OR = 3.03, p < 0.001), with an increase of both DQ-LTR3 homozygous and heterozygous patients, when compared to DRB1*04 positive controls (p = 0.0015). HLA-DR/DQ genotype analysis among HLA-DRB1*04 positive individuals revealed significantly more DQ-LTR3 homozygotes among HLA-DRB1*04-DQBI*03 homozygous patients (72% vs 27%, P = 0.015), and the number of DQ-LTR3 homozygous (23% vs 19%) and heterozygous (66% vs 53%) individuals was also increased among HLA-DRB1*04 heterozygous patients (p = 0.034). The presence of the DQ-LTR3 element increased both the relative risk and the positive predictive value for either DRB1*04-DQB1*03 positive/negative individuals when compared to the presence of HLA-DRB1*04-DQB1*03 alone. In conclusion, these data suggest that this DQ-LTR3 enhances susceptibility to RA.

Endogenous retroviral long terminal repeats of the HLA-DQ region are associated with susceptibility to insulin-dependent diabetes mellitus.

HLA-DQ genes are the main inherited factors predisposing to IDDM. This gene region harbors long terminal repeat (DQ LTR) elements of the human endogenous retrovirus HER V-K, which we analyzed for a possible association with disease. We first investigated whether LTR segregate with DQ alleles in families. Members (n = 110) of 29 families with at least one diabetic child, unrelated patients with IDDM (n = 159), and healthy controls (n = 173) were analyzed. Genomic DNA was amplified for DQ LTR3 by a nested primer approach as well as for DQA1 and DQB1 second exons, to assign DQA1 and DQB1 alleles. DQ LTR segregated in 24 families along with DQ alleles. Of the 29 families, 20 index patients were positive for DQ LTR. The DQ LTR was in all patients on the haplotype carrying the DQA1 *0301 and DQB1 *0302 alleles. A majority of patients had DQ LTR (62%) compared with controls (38%) (p < 1.3 x 10(-5)), even after matching for the high-risk alleles DQA1 *0501, DQB1 *0201-DQA1 *0301, and DQB1 *0302 (79% of patients and 48% of controls; p < 0.02). Subtyping for DRB1 *04 alleles in all DQB1 *0302+ individuals showed 56% DRB1 *0401, DQB1 *0302 [LTR' patients vs. 29% controls with the same haplotype (p < 0.002)]. In conclusion, these data demonstrate the segregation of DQ LTR with DQA1, DQB1 alleles on HLA haplotypes. Furthermore their presence on DRB1 *0401-, DQA1 *0301-, and DQB1 *0302-positive haplotypes suggest that they contribute to DQ-related susceptibility for IDDM.

Vitamin D binding protein alleles and susceptibility for type 1 diabetes in Germans.

Vitamin D has been shown to modulate the immune system thereby preventing the development of diabetes in NOD mice. Since the vitamin D binding protein (DBP) is the main transporter for vitamin D and DBP has immunomodulatory properties itself, we investigated three polymorphic sites within the DBP gene as candidates for type 1 diabetes susceptibility for the first time. 152 Caucasian families with at least one affected offspring were genotyped for intron 8 [(TAAA)n repeat] and exon 11 (HaeIII, StyI) polymorphisms. Transmission disequilibrium testing was used to detect preferential transmission to affected offspring. We found no significant transmission disequilibrium for DBP alleles. The strongest deviation from expected values was observed for the "10" allele (relative risk = 0.57, transmitted 13 of 36 times (corrected p = 0.249)). Although we cannot exclude an association of the studied DBP alleles with type 1 diabetes at present, these data do not suggest their contribution to this disease in Germans.

Interferon-gamma gene microsatellite polymorphisms in patients with Graves' disease.

Although some of the susceptibility to Graves' disease is conferred by genes in the human leucocyte antigen (HLA) region on the short arm of chromosome 6, other genetic factors must also predispose. Among the cytokines involved in thyroid autoimmunity interferon-gamma (IFN-gamma) plays a key role in the pathogenesis of Graves' disease. We therefore analyzed the first intron of the IFN-gamma gene for a dinucleotide (CA) repeat polymorphism on chromosome 12q. Two hundred two Caucasian patients with Graves' disease and 214 Caucasian controls were analyzed by polymerase chain reaction (PCR) and subsequent polyacrylamide gel electrophoresis technique: eight different alleles designated as IFN-gamma*1 to IFN-gamma*8 could be differentiated. Among Graves' disease patients IFN-gamma*5 (12.9% vs. 6.8%, p < 0.04) was significantly more frequent whereas IFN-gamma*2 (2.5% vs. 9.8%, p < 0.002) was significantly less frequent. Patients positive for the genetic susceptibility marker HLA DQA1*0501 had significantly more IFN-gamma*3 alleles (13.6% vs. 2.6%, p < 0.009) and IFN-gamma*5 alleles (22.1% vs. 7.6%, p < 0.03) compared with DQA1*0501 positive controls. Also, among patients with endocrine ophthalmopathy IFN-gamma*3 (17.9% vs. 4.2%, p < 8 x 10(-6)) and IFN-gamma*5 (18.9% vs. 7.0%, p < 0.003) were significantly more frequent compared with controls. Although a significant association of IFN-gamma microsatellite polymorphism was observed, only a small proportion of Graves' disease patients have these markers. Thus, it is likely that the detected microsatellite polymorphisms play only a minor role in the susceptibility to Graves' disease.

Genetic markers in diagnosis and prediction of relapse in Graves' disease.

Hyperthyroidism of Graves' disease takes an unpredictable clinical course in the long-term follow-up. Whereas roughly 30-60% of patients relapse after their first antithyroid drug treatment, the likelihood of remission in the remaining group can not be foreseen. We have analysed-retrospectively-patients with Graves' disease that had been on antithyroid drug treatment for one year and were followed up thereafter. Patients were investigated for a variety of clinical parameters like ophthalmopathy status and relapse or remission as well as gene polymorphisms of the HLA and other regions. Of the 259 patients analysed so far, patients with ophthalmopathy did not differ from those without for HLA DQA1 and CTLA4 alleles tested. Also, the subgroup of patients with relapses after antithyroid drug treatment showed no different distribution of those alleles from the group with long-term remission. This study also confirms that the allele HLA DQA1* 0501 confers susceptibility to Graves' disease, furthermore, that the CTLA4-alanine 17 allele is an additional predisposing factor.

Genetic susceptibility to type 1 diabetes: clinical and molecular heterogeneity of IDDM1 and IDDM12 in a german population.

Type 1 Diabetes mellitus (IDDM) results from an immune-mediated destruction of the pancreatic b-cells. The genetic predisposition is mainly confered by variations within MHC class II region on chromosome 6p as well as the CTLA4 gene located on chromosome 2q33. We analysed the transmission of HLA DQA1, DQB1, DRB1*04 alleles as well as an endogenous retroviral element (DQLTR3) in 130 families with a type 1 diabetic offspring in order to evaluate their role in genetic susceptibility to IDDM. Also the combined transmission of HLA and CTLA4 haplotypes was investigated. MHC class II alleles were typed using sequence-specific primer analysis. The presence or absence of DQLTR3 was defined by a nested PCR approach and CTLA4 microsatellite polymorphisms were detected with fluorescence-labeled primer on an automated sequencing system. By transmission distortion test we confirm the linkage of HLA DQA1*0501 DQB1*0201 (DR3 DQ2) as well as DQA1*0301 DQB1*0302 (DR4 DQ8) with IDDM. Whereas the combination with CTLA4 risk markers leads to the highest transmission rate on DR3 positive haplotypes, the predisposing CTLA4 variant does not modulate the risk on DR4 haplotypes. However, the absence of DQLTR3 on DR3, but its presence on DR4 haplotypes significantly increases the genetic risk for type 1 diabetes. Therefore predisposing MHC class II haplotypes are defined by distinct loci which differentially control genetic susceptibility. The combined transmission of protective CTLA4 and HLA DR3 as well as DR4 haplotypes confirms the dominant role of HLA class II polymorphisms in defining disease susceptibility to type 1 diabetes mellitus.

No association between the deltaF508 cystic fibrosis mutation and type 2 diabetes mellitus.

Cystic fibrosis (CF) is one of the most common recessively inherited disorders in Caucasian populations and is caused by mutations in the CF transmembrane conductance regulator (CFTR) gene. A three base deletion known as deltaF508 occurs on about 70%, of CF chromosomes and accounts for the high prevalence of the disease. Since type 2 diabetes mellitus occurs more frequently in relatives of patients with CF than in the normal population, we addressed the hypothesis whether heterozygosity for deltaF508 might be a genetic risk factor for type 2 diabetes. We screened 301 patients with type 2 diabetes mellitus which had been treated for at least three years from diagnosis by diet or oral antihyperglycemic agents. Healthy controls (n = 282) had no family history for diabetes. The genotype distribution did not differ significantly between patients with type 2 diabetes (2% heterozygotes) and controls (3% heterozygotes). According to these results, we conclude, that the deltaF508 mutation in its heterozygous form does not represent a major genetic risk factor for type 2 diabetes mellitus.

[Genetic risk markers in Graves' disease]. / Genetische Risikomarker des Morbus Basedow.

Graves' disease is exceptional as a disorder of stimulatory autoimmunity in comparison with all other endocrine autoimmunopathies. Research into its pathogenesis has so far focussed on the genetics next to characterisation of antibody-antigen as well as T-lymphocyte interactions. A multigenic predisposition similar to other autoimmune diseases has been proposed. Such polygenic disorders are frequent in the population and require special genetic epidemiological tools to dissect the many gene loci, where polymorphisms are readily detectable by several molecular typing assays. This review presents these tools and methods as well as the currently identified main susceptibility loci in the Human Leukocyte Antigen (HLA DQA1*0501), cytotoxic T-lymphocyte antigen 4 (CTLA4-ala17) as well as interferon-gamma (IFN-gamma *2) regions. Most of these predisposing alleles are shared risk factors in several endocrine autoimmune diseases. Further research is required to identify those gene variants that determine the individual course of thyroid stimulation or destruction.

Polymorphisms of tumor necrosis factor receptor 2 are not associated with insulin-dependent diabetes mellitus or Graves' disease.

Insulin-dependent diabetes mellitus (IDDM) and Graves' disease (GD) are autoimmune endocrinopathies and associated with distinct HLA-DR and -DQ alleles as well as several tumor necrosis factor alpha (TNF-alpha) and beta (TNF-beta) alleles. TNF-alpha and TNF-beta interact with TNF receptor (TNF-R), of which two subtypes have been described: TNF-R1 and TNF-R2. We investigated TNF-R2 alleles in 90 patients with IDDM, 101 with GD and 70 healthy controls. Genomic DNA was amplified with specific flanking primers for the untranslated 3' region of TNF-R2. SSCP analysis revealed two alleles by different fragment patterns: TNF-R2*1 and TNF-R2*2. Patients with IDDM or Graves' disease and controls did not differ significantly: TNF-R2*1/*1:IDDM(8%)/GD(2%)/KO(4%); TNF-R2*2/*2:IDDM(34%)/GD(48%)/KO(42%), heterozygosity TNF-R2*1/*2:IDDM(58%)/GD(50%)/KO(54%) (IDDM vs KO: P=0.46, chi2=1.57; GD vs KO: P=0.59, chi2=1.05). In conclusion, the studied polymorphism of TNF-R2 was associated with neither IDDM nor GD in a German population.

HLA-DMA and HLA-DMB alleles in German patients with type 1 diabetes mellitus.

The HLA-DMA and HLA-DMB genes are located in the HLA-D region between DQ and DP. Four variants of DMA (DMA*0101-0104) and five of the DMB (DMB*0101-0105) have so far been identified. HLA-DM molecules are required in the process of peptide loading to HLA class II antigens, both regulating the dissociation of class II-associated invariant chain peptides (CLIP) and the subsequent binding of exogenous peptides to HLA class II molecules. In order to investigate the immunogenetic heterogeneity within the HLA-D susceptibility region, we analysed the distribution of DMA alleles in 125 patients with type 1 diabetes mellitus and 90 healthy controls, and of DMB alleles in 102 patients and 89 healthy controls. Patients and controls were all from central Germany. The polymerase chain reaction (PCR) amplified products were purified and separated on a 10% polyacrylamide gel electrophoresis. Among the four recognized DMA alleles, DMA*0102 was significantly less frequent (12% vs. 28.9%, P<0.01) in patients with type 1 diabetes mellitus. DMB*0101 (70.6% vs. 97.8%, P<5.5x10(-3)) was also reduced in frequency compared to controls. Comparing patients and controls positive for the type 1 diabetes high-risk markers we found a significant association between DMA*0102 and DQA*0501 (9.5% vs. 39.1%, P<0.02), as well as DMB*0101 and DQA*0501 (62.5% vs. 96.2%, P<0.03). In conclusion, DMA*0102 and DMB*0101 contribute to genetic protection to type 1 diabetes mellitus in individuals with high-risk DQA markers in the German population.