The HLA-G molecule presents immunomodulatory properties that might inhibit immune responses when interacting with specific Natural Killer and T cell receptors, such as KIR2DL4, ILT2 and ILT4. Thus, HLA-G might influence the outcome of situations in which fine immune system modulation is required, such as autoimmune diseases, transplants, cancer and pregnancy. The majority of the studies regarding the HLA-G gene variability so far was restricted to a specific gene segment (i.e., promoter, coding or 3' untranslated region), and was performed by using Sanger sequencing and probabilistic models to infer haplotypes. Here we propose a massively parallel sequencing (NGS) with a bioinformatics strategy to evaluate the entire HLA-G regulatory and coding segments, with haplotypes inferred relying more on the straightforward haplotyping capabilities of NGS, and less on probabilistic models. Then, HLA-G variability was surveyed in two admixed population samples of distinct geographical regions and demographic backgrounds, Cyprus and Brazil. Most haplotypes (promoters, coding, 3'UTR and extended ones) were detected both in Brazil and Cyprus and were identical to the ones already described by probabilistic models, indicating that these haplotypes are quite old and may be present worldwide.

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The contribution of specific HLA Class II alleles in type 1 diabetes is determined by polymorphic amino acid epitopes that direct antigen binding therefore, along with conventional allele frequency analysis, epitope analysis can provide important insights into disease susceptibility. We analyzed the highly heterogeneous Cypriot population for the HLA class II loci of T1DM patients and controls and we report for the first time their allele frequencies. Within our patient cohort we identified a subgroup that did not carry the DRB1*03:01-DQA1*05:01-DQB1*02:01 and DRB1*04:xx-DQA1*03:01-DQB1*03:02 risk haplotypes but a novel recombinant one, DRB1*04:XX-DQA1*03:01-DQB1*02:01 designated DR4-DQ2.3. Through epitope analysis we identified established susceptibility (DQB1 A57, DRB1 H13) and resistance (DQB1 D57) residues as well as other novel susceptibility residues DRB1 Q70, DQB1 L26 and resistance residues DRB1 D70, R70 and DQB1 Y47. Prevalence of susceptibility epitopes was higher in patients and was not exclusively a result of linkage disequilibrium. Residues DRB1 Q70, DQB1 L26 and A57 and a 10 amino acid epitope of DQA1 were the most significant in discriminating risk alleles. An extended haplotype containing these epitopes was carried by 92% of our patient cohort. Sharing of susceptibility epitopes could also explain the absence of risk haplotypes in patients. Finally, many significantly associated epitopes were non-pocket residues suggesting that critical immune functions may exist spanning further from the binding pockets.

Type I diabetes mellitus (T1DM) is an organ-specific autoimmune disorder affecting the insulin-producing pancreatic cells. T1DM genetic association studies have so far revealed the involvement of more than 40 loci, with particularly strong associations for the human leucocyte antigens (HLA). Further to the well-established HLA class II associations, the immunomodulatory elements in the telomeric major histocompatibility complex locus, specifically nonclassical HLA class I, were also associated with T1DM, either in conferring susceptibility or by contributing to the overall pathogenesis. This study investigates the involvement of a 14-bp deletion polymorphism (rs371194629) at the 3' untranslated region of HLA-G in the context of T1DM and age of onset. The frequency of the polymorphism was determined in unrelated T1DM Cypriot patients and findings that emerge from this study show a strong association between the HLA-G 14-bp polymorphism and T1DM with respect to the age of onset. Specifically, the deletion/deletion (DEL/DEL) genotype was found to be associated with an early age of onset (P = 0.001), while the presence of the insertion allele (INS) was associated to a later age of onset (P = 0.0001), portraying a possible dominant effect over the deletion allele, a role in delaying disease onset and an overall involvement of HLA-G in the pathogenesis of type I diabetes mellitus.

BackgroundThe synthesis of complementary DNA (cDNA) for use in the detection of BCR-ABL1 at the Major Molecular Response (MMR) level is a well-established method used by clinical laboratories world-wide. However, the quality of cDNA provides sensitivity challenges and consequently affects the detection of Minimal Residual Disease (MRD).ResultsHerein, we evaluated six commercially available kits for the synthesis of cDNA according to amplification success rate, linearity and ABL1 copy number. Based on our results, the Invitrogen SuperScript® III Reverse Transcriptase kit performed better, among the ones used in this study, for the cDNA synthesis, followed by the First Strand cDNA Synthesis Kit for RT-PCR (AMV), available from Roche Applied Sciences.ConclusionsAccurate and sensitive testing for the detection of abnormal transcripts, allows the correct stratification and treatment of patients. Hence, the use of a suitable kit for the cDNA synthesis is of great importance. This study provides a comprehensive point of reference for clinical laboratories in an attempt to optimize BCR-ABL1 detection. We propose that the Invitrogen SuperScript® III Reverse Transcriptase kit is the most suitable, among the ones used in this study, for the cDNA synthesis to be used for the detection of BCR-ABL1 at the MMR level in a CML MRD assay.Electronic supplementary materialThe online version of this article (doi:10.1186/s12575-015-0014-x) contains supplementary material, which is available to authorized users.