European Society Paediatric Gastroenterology, Hepatology and Nutrition Guidelines for Diagnosing Coeliac Disease 2020.

OBJECTIVES: The ESPGHAN 2012 coeliac disease (CD) diagnostic guidelines aimed to guide physicians in accurately diagnosing CD and permit omission of duodenal biopsies in selected cases. Here, an updated and expanded evidence-based guideline is presented. METHODS: Literature databases and other sources of information were searched for studies that could inform on 10 formulated questions on symptoms, serology, HLA genetics, and histopathology. Eligible articles were assessed using QUADAS2. GRADE provided a basis for statements and recommendations. RESULTS: Various symptoms are suggested for case finding, with limited contribution to diagnostic accuracy. If CD is suspected, measurement of total serum IgA and IgA-antibodies against transglutaminase 2 (TGA-IgA) is superior to other combinations. We recommend against deamidated gliadin peptide antibodies (DGP-IgG/IgA) for initial testing. Only if total IgA is low/undetectable, an IgG-based test is indicated. Patients with positive results should be referred to a paediatric gastroenterologist/specialist. If TGA-IgA is ≥10 times the upper limit of normal (10× ULN) and the family agrees, the no-biopsy diagnosis may be applied, provided endomysial antibodies (EMA-IgA) will test positive in a second blood sample. HLA DQ2-/DQ8 determination and symptoms are not obligatory criteria. In children with positive TGA-IgA <10× ULN at least 4 biopsies from the distal duodenum and at least 1 from the bulb should be taken. Discordant results between TGA-IgA and histopathology may require re-evaluation of biopsies. Patients with no/mild histological changes (Marsh 0/I) but confirmed autoimmunity (TGA-IgA/EMA-IgA+) should be followed closely. CONCLUSIONS: CD diagnosis can be accurately established with or without duodenal biopsies if given recommendations are followed.

Evaluation of T cells in blood after a short gluten challenge for coeliac disease diagnosis.

BACKGROUND AND AIM: To diagnose coeliac disease (CD) in individuals on a gluten free diet (GFD), we aimed to assess the utility of detecting activated γδ and CD8 T cells expressing gut-homing receptors after a short gluten challenge. METHODS: We studied 15 CD patients and 35 non-CD controls, all exposed to three days of gluten when following a GFD. Peripheral blood was collected before and six days after starting gluten consumption, and the expression of CD103, ß7 and CD38 in γδ and CD8 T cells was assessed by flow cytometry. Determination of IFN-γ and IP-10 was performed by means of ELISPOT and/or Luminex technology. RESULTS: We observed both γδ and CD8 T cells coexpressing CD103, ß7hi and CD38 in every patient with CD on day six, but only in one control. The studied CD8 T subpopulation was easier to detect than the γδ subpopulation. Increased IFN-γ and IP-10 levels after challenge were observed in patients with CD, but not in controls. CONCLUSION: A short three-day gluten challenge elicits the activation of CD103+ ß7hi CD8+ T cells in CD. These cells can be detected by flow cytometry in peripheral blood, opening new possibilities for CD diagnosis in individuals on a GFD.

Is celiac disease better identified through HLA-DQ8 than through HLA-DQ2 in Mexican subjects? / ¿Es posible una mejor identificación de la enfermedad celiaca en sujetos mexicanos por medio de HLA-DQ8 que de HLA-DQ2?

INTRODUCTION AND AIMS: A strong genetic association between celiac disease (CD) and the human leukocyte antigen (HLA) has been widely demonstrated. In Europe, the HLA-DQ2 allele is predominant. However, studies in Latin America indicate that HLA-DQ8 could be more frequent. In Mexico, the frequency of those alleles has not been reported in subjects with CD. Therefore, the aim of the present study was to evaluate the distribution of HLA-DQ2 and HLA-DQ8 in Mexican individuals with CD. MATERIAL AND METHODS: An exploratory study was conducted on a cohort of 49 subjects with chronic diarrhea. Autoantibodies for CD, duodenal atrophy, and HLA haplotypes were determined. RESULTS: Thirty individuals had CD (23 women, mean age 54.2 ± 15.5 years), 24 (80%) of whom expressed HLA-DQ8, 15 (50%) expressed HLA-DQ2, and 11 (37%) presented with both alleles. However, neither the HLA-DQ2 nor the HLA-DQ8 allele was found in 5 (10%) individuals. In subjects with chronic diarrhea that did not have CD, 12 (63%) presented with HLA-DQ2, and 7 (37%) with HLA-DQ8. Individuals with CD expressed the combinations of the HLA-DQ8/DQ2 alleles (37 vs. 5%) and the HLA-DR4/DQ8 alleles (60 vs. 26%) more frequently than the subjects without CD. CONCLUSIONS: In Mexican subjects with CD, HLA-DQ8 distribution was more frequent than that of HLA-DQ2, indicating a possible similarity to the frequency reported in other Latin American countries. However, given the nature of the present study and its sample size, further conclusions could not be reached.

Human leukocyte antigen matching in organ transplantation: what we know and how can we make it better (Revisiting the past, improving the future).

PURPOSE OF REVIEW: A renaissance for human leukocyte antigen (HLA) testing emerged with the understanding that donor-specific HLA antibodies play a significant role in long-term allograft survival. This renewed focus on donor/recipient histocompatibility led to a recent quest to decipher antibody responses or, as introduced into the transplantation lexicon, 'HLA-epitope matching'. RECENT FINDINGS: Whether matching is at the antigen or the epitope level, in-depth understanding of how histo-incompatibility leads to activation of an immune response is required. HLA-DQ donor-specific antibody (DSA) has the highest association with poor graft survival. However, HLA-DQ antigens and antibodies are understudied and significant gaps still exist in understanding the function of HLA-DQ in immune activation. Much of our knowledge about HLA class-II molecules is derived from studies performed on HLA-DR, whether it is crystallography, antigen processing and presentation analysis, or activation of T-cell signal-transduction pathways. Indeed, HLA-DQ molecules are less amenable for laboratory testing, but the limited studies that were performed indicate that HLA-DQ might have, at least to some extent, a different role compared with HLA-DR. SUMMARY: This review highlights qualities of HLA-DQ that may be associated with different pathways of activating an immune response. Understanding the consequences of such differences may lead to better appreciation and significance of HLA-DQ for matching purposes.

Celiac antibodies in children with type 1 diabetes - A diagnostic validation study.

INTRODUCTION: Autoimmune diseases, such as celiac disease (CD) and diabetes mellitus type 1, tend to co-occur within the same patient. The prevalence of CD in diabetic children is higher than in the general population, and is estimated to be 0.6-16.4%. The diagnosis of CD is based on histopathological examination and serological testing, however, these methods are still imperfect and new diagnostic algorithms should be considered. AIM: The aim of the study was to assess the diagnostic value of serological tests detecting antibodies against deamidated gliadin peptide, endomysium, tissue transglutaminase, neo-epitope tissue transglutaminase and to identify HLA-related genetic predisposition to CD in patients with type 1 diabetes mellitus (DM1). METHODS: Autoantibodies were measured in the sera of 392 children suffering from DM1 aged 1-19 years old (mean 11.76 ± 4.14 years old). Additionally, PCR-based assessment of HLA DQ2/DQ8 genotyping was performed. RESULTS: A positive result of at least one serological test was obtained from 81 children (20.66%). The sensitivity and specificity were 76.47% and 91.67% for anti-DGP IgA, 70.59% and 58.33% for IgG anti-DGP, respectively. A positive predictive value was 100% for the anti-TG IgA at cutoff levels of 5 and 10 times higher than upper limit of reference values. HLA DQ2 and/or DQ8 were found in 97.6% of examined children. CONCLUSIONS: Tests based on anti-TG IgA are more accurate for detecting CD in children with type 1 diabetes than anti-DGP IgA. A high percentage of diabetic children carry HLA alleles predisposing to CD, which indicates that genetic screening in this group of patients is not obligated.

A study on HLA-DR/DQ typing in adult Malay patients with acute amoebic liver abscess.

INTRODUCTION: Amoebiasis is a parasitic disease caused by Entamoeba histolytica that may lead to death in developing countries. Few important risk factors have been identified in the development of amoebic liver abscess (ALA). There are limited reports that suggest an association between antigens of the major histocompatibility complex (MHC) particularly class II antigens and ALA development. This present work aimed at studying the possible association of HLA antigens with ALA and disease severity. Results of the study may serve as a guide for further immunological studies dealing with E. histolytica. METHODS: This preliminary study involved two groups of subjects: 20 ALA patients in the experimental group and 40 healthy individuals in the control group. Cases were selected from adult Malay patients confirmed with ALA based on clinical signs and symptoms, radiological findings, microbiological findings and who were admitted to the medical or surgical ward, Hospital USM, Kelantan. Venous blood was obtained from each patient and HLA typing was then conducted using polymerase chain reaction specific primer sequence. RESULTS: HLA DR12 was most frequently found in the healthy control and ALA groups at 40% and 55% respectively. HLA DQ7 and DQ8 were found to have the highest percentage in the ALA group at 65%. In the control group, HLA DQ8 (57.5%) had the highest percentage. CONCLUSION: HLA antigens play a role in acquisition of ALA and provide understanding of the disease outcome.

Serum 25-Hydroxyvitamin D Concentrations in Children Progressing to Autoimmunity and Clinical Type 1 Diabetes.

CONTEXT: The role of vitamin D in the development of type 1 diabetes (T1D) remains controversial. OBJECTIVE: The objective of the investigation was to study whether there are detectable differences in serum 25-hydroxyvitamin D (25[OH]D) concentrations between children who later progressed to T1D (cases) and matched children who remained nondiabetic and negative for islet autoantibodies (controls) when followed up from birth until disease onset. DESIGN: A total of 3702 prospective serum samples from 252 children were measured for 25(OH)D from the age of 3 months onward using an enzyme immunoassay. Differences between the groups were compared by the mixed-model analysis of variance. SETTING: T1D prediction and prevention study clinics in Turku, Oulu, and Tampere University Hospitals, Finland, participated in the study. PARTICIPANTS: By the end of 2012, all 126 case children were diagnosed with T1D. The control children (n = 126) were matched for age, sex, study site, and human leukocyte antigen-HLA-DQ-conferred risk for T1D. MAIN OUTCOME MEASURE: Median circulating 25(OH)D concentration (nanomoles per liter) was measured. RESULTS: The patterns of variation in circulating 25(OH)D concentrations were similar between cases and controls and did not correlate with the age at seroconversion to autoantibody positivity (P = .79) or disease onset (P = .13). The median concentration of all collected samples did not differ between case and control children (66.6 nmol/L [range 14.0-262.8] vs 67.4 nmol/L [range 19.9-213.0]) P = .56). CONCLUSIONS: This study shows that serum 25(OH)D concentrations are not associated with the development of T1D in Finland.

Serological Screening for Celiac Disease in Adult Chinese Patients With Diarrhea Predominant Irritable Bowel Syndrome.

Celiac disease (CD) is common in Caucasians, but thought to be rare in Asians. Our aim was to determine the prevalence of CD in Chinese patients with chronic diarrhea predominant irritable bowel syndrome (IBS-D).From July 2010 to August 2012, 395 adult patients with IBS-D and 363 age and sex-matched healthy controls were recruited in Zhongnan Hospital of Wuhan University and Xiaogan Central Hospital in Hubei province, central China. Patients with IBS-D were diagnosed according to the Rome III criteria. Serum Immunoglobulin (IgA/IgG) anti-human tissue transglutaminase (anti-htTG)-deamidated gliadin peptide (DGP) antibodies were measured in a single ELISA (QUANTA Lite h-tTG/DGP Screen). Upper endoscopy with duodenal biopsies and HLA-DQA1 and HLA-DQB1 genotyping were performed in seropositive subjects and a gluten-free diet was prescribed.Seven IBS-D patients (7/395, 1.77%) and 2 healthy controls (2/363, 0.55%), were positive for anti-htTG/DGP antibodies. Of these 9 cases, 1 was lost to follow-up, 3 were suspected to have CD and 5 were eventually diagnosed as CD with intestinal histological lesions classified as Marsh Type II in 2 and Type III in 3. Of these 5 diagnosed CD patients, 4 (4/395, 1.01%) were from the IBS-D group and 1 (1/363, 0.28%) from the healthy control had asymptomatic CD. Two Type III CD patients with relatively high titers in the serologic assay were homozygous and heterozygous for haplotype HLA-DQA1*03-DQB1*03:03 (HLA-DQ9.3), respectively.In the present study, CD was present in 1.01% of patients with IBS-D and in 0.28% of the control group. We like to suggest that the haplotype HLA-DQA1*03-DQB1*03:03 (HLA-DQ9.3), which is common in Chinese, is a new susceptibility factor for CD in China. Larger screening and genetic studies are needed in the Chinese population of different regions.

[Not everything is coeliac disease what it seems]. / Nem minden coeliakia, ami annak látszik. Coeliakia és gyulladásos bélbetegség együttes elofordulása.

The prevalence of inflammatory bowel disease is ten times more common in patients with celiac disease; however, studies investigating the reverse relation have contradictory findings. Many gene polymorphisms are known to be present in both diseases; furthermore, similarities observed in their pathophysiological mechanism, their family concomitance, results of the serologic analysis and their macroscopic and microscopic symptoms in the gastro-intestinal system suggest a relevant association between the two diseases. The author presents the history of four patients, of whom two had both Crohn's and coeliac diseases. In the two other patients with inflammatory bowel disease the possible diagnosis of coeliac disease was suspected, but after additional examinations coeliac disease was excluded in one patient and seemed to be unlikely in the other patient. The author concludes that the differential diagnosis of the two diseases is not easy and if one of them is diagnosed, the possible presence of the other one should be taken into consideration.

Medium-high resolution electrochemical genotyping of HLA-DQ2/DQ8 for detection of predisposition to coeliac disease.

Coeliac disease is a small intestinal disorder, induced by ingestion of gluten in genetically predisposed individuals. Coeliac disease has been strongly linked to human leukocyte antigens (HLA) located on chromosome 6, with almost 100 % of coeliac disease sufferers carrying either a HLA-DQ2 or HLA-DQ8 heterodimer, with the majority carrying HLA-DQ2 encoded by the DQA1*05:01/05:05, DQB1*02:01/02:02 alleles, whereas the remaining carry the HLA-DQ8 encoded by the DQA1*03:01, DQB1*03:02 alleles. In this work, we present the development of a multiplex electrochemical genosensor array of 36 electrodes, housed within a dedicated microfluidic platform and using a total of 10 sequence-specific probes for rapid medium-high resolution HLA-DQ2/DQ8 genotyping. An evaluation of the selectivity of the designed probes was carried out with the target sequences and 44 potentially interfering alleles, including single base mismatch differentiations; good selectivity was demonstrated. The performance of the electrochemical genosensor array was validated, analyzing real human samples for the presence of HLA-DQ2/DQ8 alleles, and compared with those obtained using laboratory-based HLA typing, and an excellent correlation was obtained.

Ex-vivo whole blood secretion of interferon (IFN)-γ and IFN-γ-inducible protein-10 measured by enzyme-linked immunosorbent assay are as sensitive as IFN-γ enzyme-linked immunospot for the detection of gluten-reactive T cells in human leucocyte antigen (HLA)-DQ2·5(+) -associated coeliac disease.

T cell cytokine release assays are used to diagnose infectious diseases, but not autoimmune or allergic disease. Coeliac disease (CD) is a common T cell-mediated disease diagnosed by the presence of gluten-dependent intestinal inflammation and serology. Many patients cannot be diagnosed with CD because they reduce dietary gluten before medical workup. Oral gluten challenge in CD patients treated with gluten-free diet (GFD) mobilizes gluten-reactive T cells measurable by interferon (IFN)-γ enzyme-linked immunospot (ELISPOT) or major histocompatibility complex (MHC) class II tetramers. Immunodominant peptides are quite consistent in the 90% of patients who possess HLA-DQ2·5. We aimed to develop whole blood assays to detect gluten-specific T cells. Blood was collected before and after gluten challenge from GFD donors confirmed to have CD (n = 27, all HLA-DQ2·5(+) ), GFD donors confirmed not to have CD (n = 6 HLA-DQ2·5(+) , 11 HLA-DQ2·5(-) ) and donors with CD not following GFD (n = 4, all HLA-DQ2·5(+) ). Plasma IFN-γ and IFN-γ inducible protein-10 (IP-10) were measured by enzyme-linked immunosorbent assay (ELISA) after whole blood incubation with peptides or gliadin, and correlated with IFN-γ ELISPOT. No T cell assay could distinguish between CD patients and controls prior to gluten challenge, but after gluten challenge the whole blood IFN-γ ELISA and the ELISPOT were both 85% sensitive and 100% specific for HLA-DQ2·5(+) CD patients; the whole blood IP-10 ELISA was 94% sensitive and 100% specific. We conclude that whole blood cytokine release assays are sensitive and specific for detection of gluten-reactive T cells in CD; further clinical studies addressing the utility of these tests in patients with an uncertain diagnosis of CD is warranted.

[Clinical analysis of gluten-related disease].

OBJECTIVE: To explore the diagnosis and treatment of gluten-related disorders (GRD). METHODS: Anti-gliadin antibodies(AGA), anti-tissue transglutaminase (tTG) antibody, deamidated gliadin peptides (DGP) antibody and serum specific IgG antibodies of 14 kinds of intolerable food were tested in people who developed chronic diarrhea after the intake of gluten diet. HLA-DQ2, HLA-DQ8 and intestinal endoscopic multiple biopsies would be performed further in patients with positive coeliac disease (CD)-specific serology. Gluten free diet was given to patients with positive CD-specific serology.One patient received prednisone (30 mg/d and diminished 5 mg/w). RESULTS: Nine patients were confirmed with celiac disease (CD) and four cases were suspected non-coeliac gluten sensitivity (NCGS) in 13 patients with positive serologic tests. Twelve cases received effective therapy. In CD group, 6 cases were accompanied with comorbidities mainly autoimmune diseases and osteoporosis. The positive rates of AGA and tTG antibody were 9/9 and 2/9 respectively in the CD group, while tTG antibody in the NCGS group were both negative.Endoscopic intestinal biopsy was performed in all 13 cases. Plasma cell proliferation and lymphocyte infiltration in the lamina propria without villus atrophy were identified in 4 cases, representing chronic inflammation of the small intestine. Villus atrophy was detected in 9 cases. Two patients with NCGS ingested gluten after 4 and 6 months of gluten-free diet respectively, and the number of bowel movements increased 1-2 times per day. CONCLUSIONS: The diagnosis of CD is mainly based on serologic tests and characteristic of histological features. CD may be companied by other autoimmune diseases or metabolic disease of bone. Lifelong adherence to a gluten free diet is the most basic and effective therapy.

[Celiac disease in children from the northwest of Mexico: clinical characteristics of 24 cases]. / Enfermedad celiaca en niños del noroeste de México: características clínicas de 24 casos.

BACKGROUND: Celiac disease (CD) is an autoimmune enteropathy induced by dietary wheat gluten that can have serious consequences if not diagnosed and treated early. It is important to be familiar with other alterations associated with gluten ingestion due to the multiplicity of clinical presentations. OBJECTIVES: To describe the most common CD presentation patterns and alterations associated with gluten in children from the northwest region of Mexico, with an incipient knowledge of its prevalence. PATIENTS AND METHODS: Age, sex, family history, and gastrointestinal and extraintestinal symptoms were recorded in 24 patients within the time frame of 2006 to 2010. Biochemical and hematologic data were collected. Anti-gliadin and anti-transglutaminase antibodies were analyzed in all the cases, and haplotypes (HLA-DQ2/DQ8) and duodenal biopsy were evaluated in some of the cases. RESULTS: Of the 24 patients (14 girls and 10 boys), 13 presented with typical CD with symptoms of poor gastrointestinal absorption; 7 patients with a mean age of 5 years presented with atypical CD; 2 had disease onset with gastrointestinal and extraintestinal (neurologic) problems; and 2 with other gluten-related disorders. All of the patients had positive serology; 11/15 presented with HLA-DQ2/DQ8 and 4 with at least one allele; damaged mucosa was observed in the 6 biopsies taken. A third of the patients were anemic, 6 presented with an albumin value of<3.5g/dL, and 4 with mineral deficiencies. A total of 83% of the patients improved with a gluten-free diet. CONCLUSIONS: The presentation patterns were: 1) typical CD, 2) atypical CD, 3) CD with gastrointestinal and extraintestinal (neurologic) symptoms, and 4) gluten-related disorders other than CD.

[Lymphocytic duodenosis: etiological study and clinical presentations]. / Duodenosis linfocítica: estudio etiológico y formas de presentación clínica.

INTRODUCTION: Lymphocytic duodenosis (LD) is a characteristic lesion in the initial phases of celiac disease (CD) but can be associated with many other entities. The aim of this study was to evaluate the prevalence of distinct causes of LD and possible differences in clinical presentation according to etiology. METHODS: A retrospective study was performed that included 194 patients diagnosed with LD (more than 25 intraepithelial lymphocytes per 100 epithelial cells). A preestablished strategy to evaluate the cause of the disease was followed that included celiac serology (antitransglutaminase antibodies), HLA-DQ2/DQ8 genotypes, diagnosis of Helicobacter pylori and small intestinal bacterial overgrowth (SIBO). Diagnosis of CD was established on the basis of clinical and histological response to a gluten-free diet in patients with positive serology or compatible findings on HLA-DQ2 (at least one of the alleles) or -DQ8 (both alleles) study. RESULTS: The most frequent cause of LD was CD (39%), followed by SBBO (22%), H.pylori (14%), CD and SIBO (12%), and other causes (13%). Most of the patients (83%) had a compatible HLA-DQ2 or -DQ8 genotype. In these patients, the most frequent diagnosis was CD (46%), while in the absence of HLA-DQ2/DQ8, the most frequent diagnoses were SIBO (44%) and H. pylori (22%). CD was the most frequent diagnosis in patients referred for dyspepsia, diarrhea and anemia, while H. pylori was the most frequent diagnosis in patients with abdominal pain. CONCLUSIONS: The most common causes of LD in our environment are CD, followed by SIBO and H. pylori infection.

A multiplex assay to rapidly exclude HLA-DQ2.5 and HLA-DQ8 expression in patients at risk for celiac disease.

BACKGROUND: Celiac disease (CD) is an inflammatory disorder of the small intestine induced by gluten ingestion. CD has a strong genetic association with human leukocyte antigen (HLA)-DQ2.5 and HLA-DQ8. The absence of HLA-DQ2.5 and HLA-DQ8 has a strong negative predictive value for CD. Genetic screening of HLA-DQ2.5 and HLA-DQ8 in patients at risk is of great value. METHODS: We designed, developed, and validated a multiplex assay based on multiplex ligation-dependent probe amplification (MLPA) technology, allowing the simultaneous detection of DQA1*05-DQB1*02, encoding HLA-DQ2.5, and DQA1*03-DQB1*03:02, encoding HLA-DQ8. The amplified products were separated and identified using capillary electrophoresis. RESULTS: When compared with a polymerase chain reaction followed by single-strand conformation polymorphism/ heteroduplex analysis, one discrepancy was found. Sequencing analysis showed that the developed MLPA assay result was correct. Furthermore, we demonstrated that the MLPA method is able to distinguish between the heterozygote and homozygote expression of HLA-DQ2.5 or HLA-DQ8. CONCLUSIONS: This study shows that it is possible to rapidly and accurately screen for the absence of HLA-DQ2.5 and HLA-DQ8 using MLPA, excluding patients at risk for CD for further serological or histological follow-up. In addition, MLPA might be an accurate tool to screen for other specific HLA types in the context of disease association in a diagnostic laboratory setting.

Cutoff values and data handling for solid-phase testing for antibodies to HLA: effects on listing unacceptable antigens for thoracic organ transplantation.

Application of single-antigen solid-phase immunoassay (SPI) in virtual crossmatch-based organ allocation has been hindered by continued debate over the biologic relevance of detected antibodies and the relationship between cutoff mean fluorescence intensity (MFI) values with crossmatch testing results. To define SPI parameters accurately predicting crossmatch testing, we analyzed a series of anti-HLA antibodies from highly-sensitized patients awaiting lung or heart transplantation. Serial dilution of serum for SPI and cytotoxic crossmatch (CXM) enabled comparison over a wide spectrum of antibody "strengths". Receiver operating characteristic (ROC) analysis identified predictive cutoff values for HLA Class I and DR-specific antibodies. However, antibodies to HLA-DQ antigens demonstrated a significantly different characteristic, highlighting difficulties in interpretation of clinical significance. We also quantitatively characterized two data handling methods, MFI ratio (MR) and relative ratio (RR), to examine their potential impact on identifying unacceptable antigens. In combination with user defined cutoff values, MFI, MR and RR lead to discordant identification of antibodies. Establishment of cutoff values for MR and RR that are comparable to MFI demonstrated increased consistency in antibody identification. This single laboratory experience is an example of establishing statistically robust cutoff values and validation across different data handling methods for use of SPI in virtual crossmatch.

Predictors of associated autoimmune diseases in families with type 1 diabetes: results from the Type 1 Diabetes Genetics Consortium.

BACKGROUND: Type 1 diabetes (T1D) is a clinically heterogeneous disease. The presence of associated autoimmune diseases (AAIDs) may represent a distinct form of autoimmune diabetes, with involvement of specific mechanisms. The aim of this study was to find predictors of AAIDs in the Type 1 Diabetes Genetics Consortium data set. METHODS: Three thousand two hundred and sixty-three families with at least two siblings with T1D were included. Clinical information was obtained using questionnaires, anti-GAD (glutamic acid decarboxylase) and anti-protein tyrosine phosphatase (IA-2) were measured and human leukocyte antigen (HLA) genotyping was performed. Siblings with T1D with and without AAIDs were compared and a multivariate regression analysis was performed to find predictors of AAIDs. T1D-associated HLA haplotypes were defined as the four most susceptible and protective, respectively. RESULTS: One or more AAIDs were present in 14.4% of the T1D affected siblings. Age of diabetes onset, current age and time since diagnosis were higher, there was a female predominance and more family history of AAIDs in the group with AAIDs, as well as more frequent anti-GAD and less frequent anti-IA-2 antibodies. Risk and protective HLA haplotype distributions were similar, though DRB1*0301-DQA1*0501-DQB1*0201 was more frequent in the group with AAIDs. In the multivariate analysis, female gender, age of onset, family history of AAID, time since diagnosis and anti-GAD positivity were significantly associated with AAIDs. CONCLUSIONS: In patients with T1D, the presence of AAIDs is associated with female predominance, more frequent family history of AAIDs, later onset of T1D and more anti-GAD antibodies, despite longer duration of the disease. The predominance of certain HLA haplotypes suggests that specific mechanisms of disease may be involved.