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.

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.

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.

[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.

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.

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.

[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.

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.

HLA DR-DQ associations with cervical carcinoma show papillomavirus-type specificity.

Cervical carcinoma is now known to be associated with human papillomaviruses (HPV), but the evidence for a link with specific HLA loci is controversial. The role of genetic variation at the HLA class II loci and among HPV types in cervical carcinoma was investigated by PCR DNA amplification and oligonucleotide probe typing of paraffin-embedded invasive cervical cancer tissue from Hispanic patients and of cervical swabs from Hispanic controls. Certain HLA class II haplotypes (such as DRB1*1501-DQB1*0602) were associated significantly, while DR13 haplotypes were negatively associated with cervical carcinoma. These associations are HPV16-type specific. These results suggest that specific HLA class II haplotypes may influence the immune response to specific HPV-encoded epitopes and affect the risk of cervical neoplasia.

[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.

[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.

Celiac disease and HLA typing using real-time PCR with melting curve analysis.

Celiac disease (CD) is an autoimmune disease characterized by chronic diarrhea, inflammatory lesions of small bowel and nutritional malabsorption. CD is strongly associated with the presence of HLA-DQB*02, DQB*03:02 and DQA*05. The absence of any one of these three human leukocyte antigen (HLA) alleles rules out the diagnosis of CD in suspected patients. Here, we describe a novel method to detect the presence of these specific HLA alleles using real-time polymerase chain reaction (PCR) with melting curve analysis. Compared with current HLA typing assays, the real-time PCR method is faster, requires fewer handling steps and provides 100% sensitivity and specificity for typing of HLA-DQB*02, DQB*03:02 and DQA*05 alleles.

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.

Clonal V alpha 12.1+ T cell expansions in the peripheral blood of rheumatoid arthritis patients.

Rheumatoid arthritis (RA) represents a heterogenous disease characterized by chronic polyarthritis. Most patients with adult RA inherit HLA-DR4 or -DR1 major histocompatibility complex (MHC) genes. While the molecular basis for this genetic predisposition is unknown, the major function of these MHC-encoded molecules is to present peptides to T lymphocytes. It is hypothesized that an endogenous or environmental antigen initiates a MHC-restricted immune response mediated by T lymphocytes, which is followed by a chronic inflammatory reaction involving many cell types. In chronic RA, previous or ongoing antigenic activation might result in detectable skewing of the peripheral alpha/beta T cell receptor (TCR) repertoire. Here we demonstrate a marked expansion of V alpha 12.1-bearing CD8+ T cells in the peripheral blood (mean, 22%; range, 10-43%) of > 15% of RA patients. A major proportion of these patients shared HLA-DQ2 in addition to the expected high frequency DR1 and DR4 alleles. Detailed molecular analysis in three of the RA patients with elevated V alpha 12.1+ T cells identified repeated TCR alpha chain sequences consistent with clonal V alpha 12.1+,CD8+ T cell expansion. In addition to shared TCR V alpha 12.1 germline gene usage among unrelated subjects, a conserved J alpha motif was also detected. Together, these results suggest an antigen-driven mechanism of T cell expansion in these patients and may offer a new approach in examining specific antigen that stimulate T cells in RA.

An isotype-specific trans-acting factor is defective in a mutant B cell line that expresses HLA-DQ, but not -DR or -DP.

The B lymphoblastoid cell line clone 13 (a subclone of the mutant cell line P3JHR-1) has been found to express high levels of HLA-DQ; by contrast, HLA-DR and -DP antigens are not expressed and cannot be induced by interferon gamma. Northern blot analysis using gene-specific probes indicated that the lack of surface expression of the DR and DP antigens is due to a marked decrease in the levels of steady-state RNA for both the alpha and beta chains. Southern blots demonstrated that none of the transcriptionally repressed genes are grossly deleted. Preparations of interspecific transient heterokaryons between clone 13 and the class II antigen-positive murine B cell lymphoma, A20, resulted in reactivation of the DRA gene and surface expression of both the DR and DP molecules. The efficiency of the DRA promoter relative to the DQB promoter is markedly and specifically diminished in clone 13 (P3JHR-1) as compared with the parental cell line, Jijoye, as assayed both by transient expression of appropriate chloramphenicol acetyltransferase gene (CAT) constructs and by in vitro transcription analysis. These data clearly demonstrate the existence of an isotype-specific trans-acting factor, and provide direct evidence that the highly homologous class II genes have distinct regulatory mechanisms.

Analysis of HLA and non-HLA alleles can identify individuals at high risk for celiac disease.

BACKGROUND & AIMS: Celiac disease (CD) is a common chronic disorder of the small intestine, resulting from aberrant cellular responses to gluten peptides, and often remains undiagnosed. It is a complex genetic disorder, although 95% of the patients carry the risk heterodimer human leukocyte antigen (HLA)-DQ2. Genome-wide association studies on CD have identified 9 non-HLA loci that also contribute to CD risk, most of which are shared with other immune-related diseases. Our aim is to predict the genetic risk for CD using HLA and non-HLA risk alleles. METHODS: We selected 10 independent polymorphisms in 2,308 cases and 4,585 controls from Dutch, UK, and Irish populations and categorized the individuals into 3 risk groups, based on their HLA-DQ2 genotype. We used the summed number of non-HLA risk alleles per individual to analyze their cumulative effect on CD risk, adjusting for gender and population group in logistic regression analysis. We validated our findings in 436 Italian cases and 532 controls. RESULTS: CD cases carried more non-HLA risk alleles than controls: individuals carrying > or = 13 risk alleles had a higher CD risk (odds ratio, 6.2; 95% confidence interval, 4.1-9.3) compared with those carrying 0-5 risk alleles. Combining HLA and non-HLA risk genotypes in one model increases sensitivity by 6.2% compared with using only HLA for identification of high-risk individuals with slight decrease in specificity. CONCLUSIONS: We can use non-HLA risk factors for CD to improve identification of high-risk individuals. Our risk model is a first step toward better diagnosis and prognosis in high-risk families and population-based screening.

Altered natural killer (NK) cell frequency and phenotype in latent autoimmune diabetes in adults (LADA) prior to insulin deficiency.

Approximately 10% of the patients diagnosed with type 2 diabetes (T2D) have detectable serum levels of glutamic acid decarboxylase 65 autoantibodies (GADA). These patients usually progress to insulin dependency within a few years, and are classified as being latent autoimmune diabetes in adults (LADA). A decrease in the frequency of peripheral blood natural killer (NK) cells has been reported recently in recent-onset T1D and in high-risk individuals prior to the clinical onset. As NK cells in LADA patients have been investigated scarcely, the aim of this study was to use multicolour flow cytometry to define possible deficiencies or abnormalities in the frequency or activation state of NK cells in LADA patients prior to insulin dependency. All patients were GADA-positive and metabolically compensated, but none were insulin-dependent at the time blood samples were taken. LADA patients exhibited a significant decrease in NK cell frequency in peripheral blood compared to healthy individuals (P=0.0018), as reported previously for recent-onset T1D patients. Interestingly, NKG2D expression was increased significantly (P<0.0001), whereas killer cell immunoglobulin-like receptor (KIR)3DL1 expression was decreased (P<0.0001) within the NK cell population. These observations highlight a defect in both frequency and activation status of NK cells in LADA patients and suggest that this immunological alteration may contribute to the development of autoimmune diabetes by affecting peripheral tolerance. Indeed, recent evidence has demonstrated a regulatory function for NK cells in autoimmunity. Moreover, the decrease in NK cell number concords with observations obtained in recent-onset T1D, implying that similar immunological dysfunctions may contribute to the progression of both LADA and T1D.

Estimation of genetic risk for Type 1 diabetes mellitus in newborns on dried blood spot.

BACKGROUND: The main contribution to genetic susceptibility for Type 1 Diabetes Mellitus (T1DM) is conferred by the Human Leukocyte Antigens (HLA). AIM: We evaluated the feasibility of large scale screening on Dried Blood Spot (DBS) to estimate the genetic risk for T1DM in newborns. SUBJECTS AND METHODS: Peripheral blood DBS samples from 256 newborns, were genotyped for HLA DRB1 and DQB1 alleles identification by a commercially available assay based on a dissociation enhancer lanthanide fluorescence system available in many newborn screening laboratories. Results were compared with those obtained in two wide multicentric studies on cord blood (DIABFIN and PREVEFIN). RESULTS: Genotyping on DBS revealed 6 subjects at high risk for T1DM, 99 at moderate risk for T1DM and the remaining at low risk for T1DM. We found 100% concordance between both techniques for HLA-DQB1 and DRB1 determination, confirming the feasibility of large scale screening on DBS. CONCLUSIONS: DBSs represent a resource for future studies about new genetics markers. This assay for estimate the genetic risk of T1DM on DBS showed an excellent sensitivity, specificity and accuracy compared with conventional techniques. Moreover, this assay resulted less expensive, and it could be easily performed on material already collected for newborn screening programs.

A rapid sample method for HLA haplotype typization. A preliminary study on celiac patients.

AIM: The aim of the present work was to determine the human leukocyte (HLA) haplotype in 64 Sardinian patients affected with celiac disease, using a rapid and easy to apply sampling method that permits samples from blood drawing to be stored more easily. Numerous studies have demonstrated how the HLA system plays a very important role in immune system regulation, determining a link between this gene and a high number of pathologies including celiac disease. In fact a genetic susceptibility exists in celiac sprue, linked to HLA-DQB1*0201 and -DQB1*0302 genes which represent sierologic groups -DQ2 and -DQ8 whose early identification could be fundamental in obtaining a diagnosis of celiac disease. METHODS: To realize this study a collecting method of samples was developed through the brushing of oral mucosa, which is extremely less traumatic than the classic sampling method using blood drawing, and which also allows a long conservation period before sample analysis. Samples were later analyzed with Van Embden's DNA extraction method to extract the patient's DNA, on which we executed the Polymerase Chain Reaction (PCR). To obtain the HLA haplotype from each patient we used 8 specific primers that amplified the HLA-DQB1 allele in low-resolution. RESULTS: Out of the 64 patients we found 26 HLA-DQB1*02 homozygotes, 28 HLA-DQB1*02 heterozygotes and 10 negative samples for the HLA-DQB1*02 allele, thus confirming what had emerged from previous blood draws. CONCLUSION: These results show how the method we developed using oral brushing is a sure method to obtain samples for determining the HLA haplotype in extra-hospital areas. This could allow the use of this method to obtain early diagnosis for chronic pathologies linked to the HLA groups and for recognizing this genotype in extensive population studies.

Stratifying risk for celiac disease in a large at-risk United States population by using HLA alleles.

BACKGROUND & AIMS: Susceptibility to celiac disease (CD) is related to HLA-DQ2 and DQ8 alleles and the heterodimers they encode. The objective of this study was to stratify risk for CD on the basis of HLA-DQ genotype. METHODS: DNA from 10,191 subjects who are at risk for CD was analyzed for HLA-DQ haplotypes. Individuals with CD were identified as those who tested positive for anti-endomysial immunoglobulin A (EMA+) in an immunofluorescence assay. RESULTS: Samples homozygous for DQ2.5 (HLA-DQA1 05-DQB1 02) or DQ2.2/DQ2.5 (HLA-DQA1 05-DQB1 02 and HLA-DQA1 0201-DQB1 02) comprised 5.38% of the total; 28.28% of these were EMA+ (95% confidence interval [CI], 24.55-32.26). Of the samples that were DQ2.5 heterozygous (HLA-DQA1 05-DQB1 02); 9.09% were EMA+ (95% CI, 7.82-10.51). Among samples in which HLA-DQ8 (HLA-DQA1 03-DQB1 0302) was detected, 8.42% of homozygotes (95% CI, 3.71-15.92) and 2.11% of heterozygotes (95% CI, 1.43-3.00) were EMA+. Samples with DQ2.2/DQ8 or DQ2.5/DQ8 comprised 5.08% of the total, and 11.78% of these were EMA+ (95% CI, 9.13-14.87). HLA-DQ2 and HLA-DQ8 were absent in 4283 samples (42.03% of the total); 0.16% of these samples were EMA+ (95% CI, 0.07-0.34). CONCLUSIONS: High-resolution, sequence-specific oligonucleotide probe typing with 35 DQA1-specific and 37 DQB1-specific probes of DNA from more than 10,000 subjects was used to stratify risk of CD in an at-risk U.S. population. DQ2 homozygosity (DQ2.5/DQ2.2+2.5) increased risk for CD, estimated by the rate of EMA positivity, compared with the entire sample population and other DQ genotypes. These data suggest a quantitative relationship between the type/proportion of DQ heterodimers and the risk of CD and identify potential immunotherapeutic targets.