DQA1*0102 DQB1*0602 haplotype distinguishes coeliac disease and its complications from gluten unrelated enteropathies.

BACKGROUND: Duodenal villous atrophy is due not only to coeliac disease and its complications but also to other rare enteropathies unrelated to gluten consumption, defined as noncoeliac enteropathies. The diagnosis of noncoeliac enteropathies remains challenging, and HLA typing has been widely used to exclude coeliac disease if DQ2 and DQ8 alleles are absent. However, the frequency of the various HLA alleles in noncoeliac enteropathies is still unknown. AIMS: To describe the HLA genetic profile of patients affected by noncoeliac enteropathies who have been evaluated at our centres between 2000 and 2021, and to investigate the diagnostic role of HLA typing. METHODS: Genomic DNA was collected from 44 Italian and 19 British adult patients with noncoeliac enteropathies. Patient genotypes were compared with those of healthy Italian and British populations obtained from HLA bone marrow donors' banks. In addition, genotypes were also compared with those of patients with coeliac disease and complicated coeliac disease. RESULTS: Both in the Italian and in the British group, the DQA1*0102 DQB1*0602 haplotype and related alleles occurred significantly more frequently in patients with noncoeliac enteropathies compared to coeliac disease and complicated coeliac disease. CONCLUSIONS: Together with negative HLA-DQ2 and DQ8 haplotypes, the DQA1*0102 DQB1*0602 haplotype can be used to guide the differential diagnosis between coeliac disease and noncoeliac enteropathies.

Luminex® xMAP® technology is an effective strategy for high-definition human leukocyte antigen typing of cord blood units prior to listing.

INTRODUCTION: Allele-level donor-recipient match at HLA-A, HLA-B, HLA-C and HLA-DRB1 loci impacts the outcome after cord blood transplantation for hematologic malignancies and modifies the strategy of donor selection. High definition of both class I and II HLA loci at time of listing is a way to improve the attractiveness of cord blood bank inventories, reducing the time for donor search and procurement and simplifying donor choice, in particular, for patients of non-European heritage. METHODS: In 2014, Luminex® xMAP® technology was introduced in our laboratory practice and was applied to cord blood units typing. In this study, we evaluated the impact of this strategy in comparison with the platform in use until 2013, relying on LiPA reverse polymerase chain reaction-sequence-specific oligonucleotide (revPCR-SSO) plus polymerase chain reaction-sequence-specific primer (PCR-SSP). RESULTS: In 2014, the time for testing was shorter (141 vs 181 days on average), the number of test repetitions was lower (in particular for HLA-A locus, p = 0.026), and the cost reduced (240.7 vs 395.6 euros per unit on average) compared to 2013, demonstrating that Luminex xMAP technology is superior to the previous approach. CONCLUSION: Luminex xMAP platform has useful application in cord blood banking programs, to achieve high-definition HLA typing of cord blood units at the time of banking in a quick, accurate, and cost-effective manner.

Anti-Zinc Transporter Protein 8 Antibody Testing Is Not Informative in Routine Prediabetes Screening in Young Patients with Autoimmune Thyroiditis and Celiac Disease.

BACKGROUND/AIMS: Patients with type 1 diabetes mellitus (T1DM), autoimmune thyroiditis (ATD), and celiac disease (CD) are at increased risk for developing other autoimmune diseases. We evaluated zinc transporter 8 (ZnT8) prevalence in patients with ATD and/or CD in order to define the usefulness of ZnT8 autoantibodies for prediabetes screening. METHODS: Eighty-one young patients with ATD and/or CD were included in the study; 32 subjects with clinical onset of T1DM were enrolled as a control group. GAD65, IA-2, and ZnT8 antibodies were measured. An intravenous glucose tolerance test, C-peptide, glycosylated hemoglobin levels, and genomic analysis of HLA-DQA1* and -DQB1* were also considered in patients positive for autoantibodies. RESULTS: The ZnT8 prevalence was higher in T1DM patients than in patients with other autoimmune diseases (p < 0.001); positive ZnT8 detection was found in 2 ATD (p = 0.004) and 3 ATD + CD (p = 0.04) patients. Positive ZnT8 was associated with GAD65 (p = 0.01) but not with IA-2 positivity. No correlation between ZnT8 detection and the number of T1DM-susceptible HLA-DQ heterodimers was found. Pathological C-peptide levels and insulin response were found in subjects with islet autoimmunity and genetic susceptibility. CONCLUSION: ZnT8 autoantibodies detection in ATD and/or CD patients is low, and routine ZnT8 screening is not justified. ZnT8 evaluation may be recommended in subjects with autoimmune diseases as a marker for predicting compromised insulin secretion.

Ex vivo immunosuppressive effects of mesenchymal stem cells on Crohn's disease mucosal T cells are largely dependent on indoleamine 2,3-dioxygenase activity and cell-cell contact.

INTRODUCTION: Crohn's disease (CD) is a disabling chronic enteropathy sustained by a harmful T-cell response toward antigens of the gut microbiota in genetically susceptible subjects. Growing evidence highlights the safety and possible efficacy of mesenchymal stem cells (MSCs) as a new therapeutic tool for this condition. Therefore, we aimed to investigate the effects of bone marrow-derived MSCs on pathogenic T cells with a view to clinical application. METHODS: T-cell lines from both inflamed and non-inflamed colonic mucosal specimens of CD patients and from healthy mucosa of control subjects were grown with the antigen muramyl-dipeptide in the absence or presence of donors' MSCs. The MSC effects were evaluated in terms of T-cell viability, apoptotic rate, proliferative response, immunophenotype, and cytokine profile. The role of the indoleamine 2,3-dioxygenase (IDO) was established by adding a specific inhibitor, the 1-methyl-DL-tryptophan, and by using MSCs transfected with the small interfering RNA (siRNA) targeting IDO. The relevance of cell-cell contact was evaluated by applying transwell membranes. RESULTS: A significant reduction in both cell viability and proliferative response to muramyl-dipeptide, with simultaneous increase in the apoptotic rate, was found in T cells from both inflamed and non-inflamed CD mucosa when co-cultured with MSCs and was reverted by inhibiting IDO activity and expression. A reduction of the activated CD4(+)CD25(+) subset and increase of the CD3(+)CD69(+) population were also observed when T-cell lines from CD mucosa were co-cultured with MSCs. In parallel, an inhibitory effect was evident on the expression of the pro-inflammatory cytokines tumor necrosis factor-α, interferon-γ, interleukin-17A and -21, whereas that of the transforming growth factor-ß and interleukin-6 were increased, and production of the tolerogenic molecule soluble HLA-G was high. These latter effects were almost completely eliminated by blocking the IDO, whose activity was upregulated in MSCs co-cultured with CD T cells. The use of a semipermeable membrane partially inhibited the MSC immunosuppressive effects. Finally, hardly any effects of MSCs were observed when T cells obtained from control subjects were used. CONCLUSION: MSCs exert potent immunomodulant effects on antigen-specific T cells in CD through a complex paracrine and cell-cell contact-mediated action, which may be exploited for widespread therapeutic use.

Soluble HLA-G in pregnancies complicated by autoimmune rheumatic diseases.

Autoimmune rheumatic diseases in pregnancies are associated with increased adverse obstetric outcomes. We compared maternal soluble human leucocyte antigen-G (sHLA-G) blood levels in subjects with a rheumatic disease preexisting pregnancy and unaffected controls. Third-trimester blood maternal sHLA-G concentrations were significantly higher in subjects with rheumatic diseases than in controls (mean 93.1ng/ml [SD 42.1] vs 58.1ng/ml [SD 96.3], p=0.003). Cord blood sHLA-G concentrations were significantly higher in rheumatic disease than in those born to control mothers (median 41.2ng/ml [IQR: 3.3-44.0] vs 17.9ng/ml [IQR: 17.2-88.1], p=0.007). A strict positive correlation (r=0.88, p<0.001) was found between the maternal and fetal titers of ANA autoantibodies as well as between maternal and fetal sHLAG circulating levels (r=0.58 and r=0.67, respectively, for controls and cases, p<0.001). Maternal s-HLA-G blood concentrations were significantly higher in subjects with rheumatic disease DEL/DEL homozygous for a polymorphism of the 3' untranslated regulatory region of HLA-G (HLA-G 14bp) than in the corresponding healthy controls (mean values 141.5ng/ml [SD: 166] vs 54.2ng/ml [SD: 35], p=0.009). Increasing maternal and cord blood levels of s-HLA-G concentrations among pregnant subjects with rheumatic diseases compared with controls suggest that autoimmune diseases prompt a maternal and fetal immune response that favors pregnancy immune tolerance.

Tolerogenic effect of mesenchymal stromal cells on gliadin-specific T lymphocytes in celiac disease.

BACKGROUND AIMS: Celiac disease is caused by a dysregulated immune response toward dietary gluten, whose only treatment is a lifelong gluten-free diet. We investigated the effects of mesenchymal stromal cells (MSCs) on gliadin-specific T cells, which are known to induce intestinal lesions, in view of a possible use as new therapy. METHODS: Bone marrow-derived MSCs and gliadin-specific T-cell lines were obtained from allogeneic donors and mucosal specimens of celiac patients, respectively. The immunosuppressant effect of MSCs was evaluated in terms of proliferative response and interferon (IFN)-γ production upon gliadin stimulation of long-term T-cell lines; the immunomodulant effect was assessed in terms of apoptotic rate, immunophenotype and cytokine profile of short-term T-cell lines generated in the presence of MSCs. Different MSC:T-cell ratios were applied, and statistics were performed as appropriate. RESULTS: MSCs inhibited both proliferative response and IFN-γ production of long-term T-cell lines in a dose-dependent manner while limiting the expansion of short-term T-cell lines by increasing the apoptotic rate. Moreover, a reduction of the CD4(+) population and expansion of the regulatory FoxP3+ subset were found in T-cell lines cultured with MSCs, in which a significant decrease of interleukin (IL)-21, IFN-γ and IL-10 paralleled by an upregulation of transforming growth factor-ß1, IL-6 and IL-8 were observed. Finally, an increase of the indoleamine 2,3-dioxygenase activity was found, possibly playing a key role in mediating these effects. CONCLUSIONS: MSCs exert potent immunomodulant effects on gliadin-specific T cells, which may be exploited for future therapeutic application in celiac disease.

Temporal variation in soluble human leukocyte antigen-G (sHLA-G) and pregnancy-associated plasma protein A (PAPP-A) in pregnancies complicated by gestational diabetes mellitus and in controls.

PROBLEM: To target gestational diabetes mellitus (GDM) by means of temporal variation in pregnancy-associated plasma protein A (PAPP-A) and soluble human leukocyte antigen-G (sHLA-G). METHOD OF STUDY: Retrospective analysis of PAPP-A and sHLA-G blood levels in historical samples of 112 GDM and 112 controls, drawn at first trimester, and prospective study in 18 GDM and 105 controls collected in triplicate along the pregnancy. Six hundred and sixty-five samples were analyzed. RESULTS: Gestational diabetes mellitus had significantly lower first-trimester PAPP-A concentrations than controls (2343±1519 versus 2996±1955 mU/mL, in retrospective brunch and 2490.57±1828.52 versus 3240.84±1930.69 mU/L in prospective one, P<0.001). First-trimester sHLA-G level was significantly lower in GDM than in controls (52.88±59.69 versus 66.81±50.14 ng/mL, P<0.001) and increased during gestation in diabetic women showing an opposite trend with respect to the controls. CONCLUSION: PAPP-A and sHLA-G are independent markers of GDM. Quantitative variations during pregnancy help to early unravel the onset of GDM.

Common immunogenetic profile in children with multiple autoimmune diseases: the signature of HLA-DQ pleiotropic genes.

Type 1 diabetes mellitus (T1DM), celiac disease (CD) and autoimmune thyroid disease (ATD) are autoimmune conditions relatively common in paediatric age and frequently occur in association in the same subject. This event is not by chance and requires an explanation. Here, we studied the distribution of HLA-DQ αß heterodimers in 334 Italian children with T1DM, ATD and CD alone or in association and in 224 Italian healthy controls. In particular, 164 patients had T1DM (133 alone, 20+ATD, 7+CD and 4+CD+ATD), 118 had ATD (110 alone, 8+CD) and 52 had CD (40 alone, 11+ATD and 1+T1DM). 51 patients suffered from multiple autoimmune diseases. The risk for multiple autoimmune diseases was significantly associated with the increased number of HLA-DQ markers of susceptibility for both T1DM (p = 0.003) and CD (p = 0.006). The presence of one or more diabetogenic DQ molecules significantly increased the probability of developing not only T1DM (p < 0.001) but also CD (p < 0.001) and ATD (p = 0.001). Similarly, the presence of one or more celiac HLA-DQ heterodimers significantly increased the likelihood of developing not only CD (p < 0.001), but also T1DM (p < 0.001) and ATD (p < 0.001). We confirm that the sharing of the immunogenetic background is responsible for the development of multiple autoimmune diseases although with a different risk according to the number and type of susceptible HLA-DQ heterodimers as reported in the algorithm proposed here. It is likely that combinations of DQA1 and DQB1 alleles are the real culprits of the progression towards multiple autoimmune diseases and HLA-DQ genomic typing will improve the capability to predict associated autoimmune diseases in infancy.

Influence of HLA-DQ2 and DQ8 on severity in celiac Disease.

BACKGROUND: HLA-DQB1*02 homozygosity was shown to be more common in patients with complicated rather than uncomplicated celiac disease (CD). GOALS: To study HLA-DQA1 and DQB1 profile in adult patients with different forms of CD, including patients with complicated and potential CD, the most affected and the most preserved histologic end of the pathologic celiac spectrum. STUDY: HLA-DQA1 and DQB1 molecular typing was performed in 218 adult CD patients (169 with uncomplicated CD, 27 with complicated CD, and 22 with potential CD) and 224 healthy stem cell donors. HLA-DQA1 and DQB1 gene polymorphism was analyzed using polymerase chain reaction sequence-specific primers and/or reverse polymerase chain reaction sequence-specific oligonucleotides techniques. RESULTS: As expected, the frequency of HLA-DQB1*02 allele, DQB1*02 homozygosity, and DQB1*0302 gene were statistically different in the 4 groups. However, multivariate analysis demonstrated that patients with potential CD have a higher frequency of both HLA-DQB1*0302 and HLA-DQB1*0603 alleles and a reduced frequency of DQB1*02 homozygosity compared with patients with uncomplicated and complicated CD. CONCLUSIONS: The increased frequency of DQB1*0302 and the reduced frequency of DQB1*02 homozygosity in potential CD is consistent with the idea that different clinical/pathologic evolutions might be related to different immunogeneses. This could be clinically relevant in the future.

Implementing non-invasive RHD genotyping on cell-free foetal DNA from maternal plasma: the Pavia experience.

BACKGROUND: The occurrence of cell-free foetal DNA in maternal circulation opens new possibilities in non-invasive antenatal diagnosis. Real-time polymerase chain reaction (PCR) analysis is an useful approach to foetal RhD blood group determination, thus being important in the prevention of haemolytic disease of foetus and new-born (HDFN). STUDY DESIGN AND METHODS: Using real-time PCR assays we typed 20 samples of plasma, provided in a blinded fashion, from the International Reference Laboratory, two plasma samples sent by the "2010 Workshop on Molecular Blood Group Genotyping"; seven samples from D-negative mothers at the 16th week of gestation provided by our Hospital as prospective validation cases, and two plasma samples received from the "1(st) Collaborative study establishing the sensitivity standard for non-invasive prenatal determination of foetal RHD genotype". To confirm the RHD typing of the seven prospective samples, PCR with sequence specific primers (PCR-SSP) was applied on genomic DNA from amniocytes (5 cases) and paternal peripheral blood (2 cases). RESULTS: The results for the 31 investigated samples showed 100% concordance. Our measurable benefits were: confidence with a new technology, awareness of having gained the European standard level and increased self-assurance regarding the introduction of this typing technique in prenatal diagnostics. DISCUSSION: These results demonstrate the feasibility and accuracy of our validation protocol. RHD typing on cell-free foetal DNA is a procedure which requires particular care and a great degree of expertise for diagnostic use. International collaborations are essential for monitoring the performance of laboratories in the absence of specific quality control programmes.

The HLA alleles DRB1*13 and DQB1*06 are associated to Whipple's disease.

BACKGROUND & AIMS: Whipple's disease is a systemic, chronic, relapsing disorder caused by a combination of environmental (Tropheryma whipplei) and unknown host factors. Because it is a rare disease, the association between HLA type and Whipple's disease has been studied in only small numbers of patients; these studies have led to conflicting results. We aimed to investigate whether disease phenotype and outcome are associated with HLA type in 122 patients with Whipple's disease. METHODS: Genomic DNA was collected from 103 German, 11 Italian, and 8 Austrian patients with Whipple's disease, along with 62 healthy Austrian workers exposed to T whipplei (14 stool samples contained the bacterium). HLA class I and II alleles were identified by polymerase chain reaction analysis. Patient genotypes were compared with those of healthy German and Austrian populations; data for Italian controls were obtained from the Pavia HLA bone marrow donors' bank. RESULTS: HLA-DRB1*13 and DQB1*06 alleles occurred significantly more frequently in patients with Whipple's disease but not in healthy individuals who had been exposed to T Whipplei. The cumulative odds ratios for disease were 2.23 for the DRB1*13 allele (P < .0001) and 2.25 for the DQB1*06 allele (P < .0001). CONCLUSIONS: DRB1*13 and DQB1*06 alleles were found to be risk factors in the largest HLA study ever performed in patients with Whipple's disease.

Specific polymorphisms of cytokine genes are associated with different risks to develop single-system or multi-system childhood Langerhans cell histiocytosis.

Cytokines and chemokines determine mobilisation of Langerhans cells and their dysregulation is implicated in the pathogenesis of Langerhans cell histiocytosis (LCH). Twenty point mutations of 12 different cytokine genes were studied in 41 Italian children, 15 with single-system (SS) and 26 with multi-system disease. The allele and genotype distributions of interleukin-4 (IL-4) and interferon-gamma (IFNgamma) were significantly different in patients vs. 140 controls (P = 0.007, and P = 0.018). Older children with single-system disease shared the 'anti-inflammatory profile' determined by the intermediate producer genotype IFNgamma +874A/T (P = 0.029) and the high-producer genotypes IL-4 -590C/T and T/T (P = 0.029). Our findings suggest that specific cytokine gene variants affect susceptibility to LCH and its clinical heterogeneity.