Expression of classical HLA class I molecules: regulation and clinical impacts: Julia Bodmer Award Review 2015.

Human leukocyte antigen (HLA) class I genes are ubiquitously expressed, but in a tissue specific-manner. Their expression is primarily regulated at the transcriptional level and can be modulated both positively and negatively by different stimuli. Advances in sequencing technologies led to the identification of new regulatory variants located in the untranslated regions (UTRs), which could influence the expression. After a brief description of the mechanisms underlying the transcriptional regulation of HLA class I genes expression, we will review how the expression levels of HLA class I genes could affect biological and pathological processes. Then, we will discuss on the differential expression of HLA class I genes according to the locus, allele and UTR polymorphisms and its clinical impact. This interesting field of study led to a new dimension of HLA typing, going beyond a qualitative aspect.

Is there any impact of HLA-DPB1 disparity in 10/10 HLA-matched unrelated hematopoietic SCT? Results of a French multicentric retrospective study.

We retrospectively analyzed the impact of HLA-DPB1 mismatches in a large cohort of 1342 French patients who underwent 10/10 HLA-matched unrelated HSCT. A significant impact of HLA-DPB1 allelic mismatches (2 vs 0) was observed in severe acute GVHD (aGVHDIII-IV) (risk ratio (RR)=1.73, confidence interval (CI) 95% 1.09-2.73, P=0.019) without impact on OS, TRM, relapse and chronic GVHD (cGVHD). According to the T-cell epitope 3 (TCE3)/TCE4 HLA-DPB1 disparity algorithm, 37.6% and 58.4% pairs had nonpermissive HLA-DPB1, respectively. TCE3 and TCE4 disparities had no statistical impact on OS, TRM, relapse, aGVHD and cGVHD. When TCE3/TCE4 disparities were analyzed in the graft-vs-host or host-vs-graft (HVG) direction, only a significant impact of TCE4 nonpermissive disparities in the HVG direction was observed on relapse (RR=1.34, CI 95% 1.00-1.80, P=0.048). In conclusion, this French retrospective study shows an adverse prognosis of HLA-DPB1 mismatches (2 vs 0) on severe aGVHD and of nonpermissive TCE4 HVG disparities on relapse after HLA-matched 10/10 unrelated HSCT.

[Impact of anti-HLA antibodies on outcomes of allogeneic stem cell transplantation: a report by the SFGM-TC]. / Impact des anticorps anti-HLA sur le devenir de l'allogreffe de cellules souches hématopoïétiques : un rapport par la SFGM-TC.

The role of anti-HLA antibodies in allogeneic stem cell transplantation setting is still unclear. In the attempt to harmonize clinical practices between different French transplantation centers, the French Society of Bone Marrow Transplantation and Cell Therapies (SFGM-TC) set up its fourth annual series of workshops which brought together practitioners from all of its member centers. These workshops took place in September 2013 in Lille. This article offers the recommendations of the group that considered the impact that have anti-HLA antibodies on outcomes in allogeneic stem cell transplantation.

[Allogeneic stem cell transplantation from an HLA-haploidentical related donor: SFGM-TC recommendations (Part 1)]. / Greffes de cellules souches hématopoïétiques à partir d'un donneur haplo-identique : recommandations de la SFGM-TC (première partie).

Haploidentical allogeneic stem cell transplantation (CST) has globally taken off in the past decade. It appears to be a valid alternative to other sources of stem cells; however, further research is necessary to validate the use of this approach in standard patient care. In the attempt to harmonize clinical practices between different French transplantation centers, the French Society of Bone Marrow Transplantation and Cell Therapies (SFGM-TC) set up its fourth annual series of workshops which brought together practitioners from all of its member centers. These workshops took place in September 2013 in Lille. This is part one of the recommendations regarding allogeneic stem cell transplantation from an HLA-haploidentical related donor.

[Allogeneic stem cell transplantation from an HLA-haploidentical related donor: SFGM-TC recommendations (part 2)]. / Greffes de cellules souches hématopoïétiques à partir d'un donneur haploidentique : recommandations de la SFGM-TC (deuxième partie).

Haploidentical allogeneic stem cell transplantation (CST) has globally taken off in the past decade. It appears to be a valid alternative to other sources of stem cells; however, further research is necessary to validate the use of this approach in standard patient care. In the attempt to harmonize clinical practices between different French transplantation centers, the French Society of Bone Marrow Transplantation and Cell Therapies (SFGM-TC) set up its fourth annual series of workshops which brought together practitioners from all of its member centers. These workshops took place in September 2013 in Lille. This is part two of the recommendations regarding allogeneic stem cell transplantation from an HLA-haploidentical related donor.

The emerging role of Twist proteins in hematopoietic cells and hematological malignancies.

Twist1 and Twist2 (Twist1-2) are two transcription factors, members of the basic helix-loop-helix family, that have been well established as master transcriptional regulators of embryogenesis and developmental programs of mesenchymal cell lineages. Their role in oncogenesis in epithelium-derived cancer and in epithelial-to-mesenchymal transition has also been thoroughly characterized. Recently, emerging evidence also suggests a key role for Twist1-2 in the function and development of hematopoietic cells, as well as in survival and development of numerous hematological malignancies. In this review, we summarize the latest data that depict the role of Twist1-2 in monocytes, T cells and B lymphocyte activation, and in associated hematological malignancies.

16(th) IHIW: analysis of HLA population data, with updated results for 1996 to 2012 workshop data (AHPD project report).

We present here the results of the Analysis of HLA Population Data (AHPD) project of the 16th International HLA and Immunogenetics Workshop (16IHIW) held in Liverpool in May-June 2012. Thanks to the collaboration of 25 laboratories from 18 different countries, HLA genotypic data for 59 new population samples (either well-defined populations or donor registry samples) were gathered and 55 were analysed statistically following HLA-NET recommendations. The new data included, among others, large sets of well-defined populations from north-east Europe and West Asia, as well as many donor registry data from European countries. The Gene[rate] computer tools were combined to create a Gene[rate] computer pipeline to automatically (i) estimate allele frequencies by an expectation-maximization algorithm accommodating ambiguities, (ii) estimate heterozygosity, (iii) test for Hardy-Weinberg equilibrium (HWE), (iv) test for selective neutrality, (v) generate frequency graphs and summary statistics for each sample at each locus and (vi) plot multidimensional scaling (MDS) analyses comparing the new samples with previous IHIW data. Intrapopulation analyses show that HWE is rarely rejected, while neutrality tests often indicate a significant excess of heterozygotes compared with neutral expectations. The comparison of the 16IHIW AHPD data with data collected during previous workshops (12th-15th) shows that geography is an excellent predictor of HLA genetic differentiations for HLA-A, -B and -DRB1 loci but not for HLA-DQ, whose patterns are probably more influenced by natural selection. In Europe, HLA genetic variation clearly follows a north to south-east axis despite a low level of differentiation between European, North African and West Asian populations. Pacific populations are genetically close to Austronesian-speaking South-East Asian and Taiwanese populations, in agreement with current theories on the peopling of Oceania. Thanks to this project, HLA genetic variation is more clearly defined worldwide and better interpreted in relation to human peopling history and HLA molecular evolution.

ENTPD1/CD39 is a promising therapeutic target in oncology.

Regulatory T cells (Tregs) are a subpopulation of CD4(+) T cells that are essential for maintaining the homeostasis of the immune system, limiting self-reactivity and excessive immune responses against foreign antigens. In cancer, infiltrated Tregs inhibit the effector lymphocytes and create a favorable environment for the growth of the tumor. Although Tregs mediate immunosuppression through multiple, non-redundant, cell-contact dependent and independent mechanisms, a growing body of evidence suggests an important role for the CD39-CD73-adenosine pathway. CD39 ectonucleotidase is the rate-limiting enzyme of a cascade leading to the generation of suppressive adenosine that alters CD4 and CD8 T cell and natural killer cell antitumor activities. Here, we review the recent literature supporting CD39 as a promising therapeutic target in oncology. In vitro and in vivo experiments involving knockout models and surrogate inhibitors of CD39 provide evidence in support of the anticancer activity of CD39 inhibition and predict a favorable safety profile for CD39 inhibitory compounds. In addition, we report the ongoing development of CD39-blocking monoclonal antibodies as potential anticancer drugs. Indeed, CD39 antagonistic antibodies could represent novel therapeutic tools for selectively inhibiting Treg function without depletion, a major limitation of current Treg-targeting strategies.

Immunological follow-up of patients with neuromyelitis optica: is there a good biomarker?

A serial assessment of biomarkers related to disease activity could be clinically useful in some autoimmune diseases. Neuromyelitis optica (NMO) is a severe inflammatory disease of the optic nerves and spinal cord that can be associated with lupus erythematosus, Sjögren syndrome or myasthenia gravis. In this review, we discuss the existing data on the use of biomarkers of disease activity in NMO. A specific and pathogenic antibody (Ab) directed against aquaporin 4 (AQP4) was recently discovered in this disease. The relapses were frequently accompanied by a rise and immunosuppressive therapy by a decrease in serum anti-AQP4 Ab concentrations. However, this association is not strong enough to justify treatment changes based only on anti-AQP4 Ab level variations. This parameter might be helpful as a longitudinal biomarker but only if a threshold inducing a relapse and justifying a switch in therapy can be established. A link between disease severity and serum cytotoxicity against AQP4-expressing cells was proposed but has not yet been confirmed. Finally, the assessment of T cell immunity against AQP4 and specific cytokines could be future directions for research.

Strategies to work with HLA data in human populations for histocompatibility, clinical transplantation, epidemiology and population genetics: HLA-NET methodological recommendations.

HLA-NET (a European COST Action) aims at networking researchers working in bone marrow transplantation, epidemiology and population genetics to improve the molecular characterization of the HLA genetic diversity of human populations, with an expected strong impact on both public health and fundamental research. Such improvements involve finding consensual strategies to characterize human populations and samples and report HLA molecular typings and ambiguities; proposing user-friendly access to databases and computer tools and defining minimal requirements related to ethical aspects. The overall outcome is the provision of population genetic characterizations and comparisons in a standard way by all interested laboratories. This article reports the recommendations of four working groups (WG1-4) of the HLA-NET network at the mid-term of its activities. WG1 (Population definitions and sampling strategies for population genetics' analyses) recommends avoiding outdated racial classifications and population names (e.g. 'Caucasian') and using instead geographic and/or cultural (e.g. linguistic) criteria to describe human populations (e.g. 'pan-European'). A standard 'HLA-NET POPULATION DATA QUESTIONNAIRE' has been finalized and is available for the whole HLA community. WG2 (HLA typing standards for population genetics analyses) recommends retaining maximal information when reporting HLA typing results. Rather than using the National Marrow Donor Program coding system, all ambiguities should be provided by listing all allele pairs required to explain each genotype, according to the formats proposed in 'HLA-NET GUIDELINES FOR REPORTING HLA TYPINGS'. The group also suggests taking into account a preliminary list of alleles defined by polymorphisms outside the peptide-binding sites that may affect population genetic statistics because of significant frequencies. WG3 (Bioinformatic strategies for HLA population data storage and analysis) recommends the use of programs capable of dealing with ambiguous data, such as the 'gene[rate]' computer tools to estimate frequencies, test for Hardy-Weinberg equilibrium and selective neutrality on data containing any number and kind of ambiguities. WG4 (Ethical issues) proposes to adopt thorough general principles for any HLA population study to ensure that it conforms to (inter)national legislation or recommendations/guidelines. All HLA-NET guidelines and tools are available through its website http://hla-net.eu.

Strategy for anti-aquaporin-4 auto-antibody identification and quantification using a new cell-based assay.

NMO-IgG is a specific biomarker of neuromyelitis optica (NMO) that targets the aquaporin-4 (AQP4) water channel protein. The current gold standard for NMO-IgG identification is indirect immunofluorescence (IIF). Our aim in this study was to develop a new quantitative cell-based assay (CBA) and to propose a rational strategy for anti-AQP4 Ab identification and quantification. We observed an excellent correlation between the CBA and IIF for NMO-IgG/anti-AQP4 detection. The CBA appeared more sensitive than IIF but on the other hand, IIF allows the simultaneous detection of various auto-Abs, underlining the complementarity between both methods. In conclusion, we propose to use IIF for the screening of patients at diagnosis in order to identify auto-Abs targeting the central nervous system. A highly sensitive, AQP4 specific and quantitative assay such as our CBA could be used thereafter to specifically identify the target of the Ab and to monitor its serum concentration under treatment.

[Economic evaluation of the organization of a registry of haematopoietic stem cell donors]. / Evaluation économique de l'organisation d'un registre de donneurs de cellules souches hématopoïétiques.

BACKGROUND: Availability of a healthy, human-leukocyte-antigen-matched hematopoietic stem cell source is a prerequisite for successful allogenic hematopoietic stem cell transplantation. In 70% of cases, the search of hematopoietic stem cells shifts from siblings to unrelated donor registries. Given that the Human Leucocytes Antigens (HLA) system is highly polymorphic and that the cost of HLA typing remains high, the adequacy between registry content and patient needs must be assessed. Registries should be optimally organized to increase the probability for any given patient to find a donor. METHODS: A welfare function associated with the existence of an HLA registry was defined as was a measure of the advantage for laboratories having performed HLA typing. We hypothesized a way to formalize registry efficiency and applied it to the French Hematopoietic Stem Cell donors Registry. RESULTS: The model determined an implicit value for the stem cell graft and showed that efficiency increased very slowly with increasing number of potential donors in registries. The optimal size of a registry was found to be sensitive to model parameters. CONCLUSION: Increased registry size, in terms of number of donors foreseeable in the French registry, would have a limited impact on registry efficiency and thus social effectiveness. Nevertheless, the calibration of the model justifies the goal of recruiting 100000 new volunteer donors over the next 10 years as proposed by the French government in the "Graft Plan". The policy of the regulatory agency should be oriented towards improving the probability a compatible potential donor identified during a preliminary search would become an actual fully compatible donor and towards reducing the cost of typing.

IL-10 promoter and IL4-Ralpha gene SNPs are associated with immediate beta-lactam allergy in atopic women.

BACKGROUND: Allergic reactions to beta-lactam antibiotics represent the most frequent cause of immunological drug reactions. OBJECTIVE: This study evaluates the involvement of genetic susceptibility factors in patients with immediate allergic reactions to beta-lactams. We examined 15 single nucleotide polymorphisms (SNP) of genes coding proteins implicated in immunoglobulin (Ig)E synthesis regulation. METHODS: We performed a case-control study involving 44 patients with immediate beta-lactam allergy and 44 control subjects, all matched for sex and atopy. Interleukin (IL)-4, IL-13, IL-4Ralpha, signal transducer and activator of transcription 6 (STAT6), interferon (IFN)-gammaR1, IFN-gammaR2 and FcepsilonRIbeta gene polymorphisms were determined using polymerase chain reaction (PCR) restriction fragment length polymorphism, and IL-21R gene and IL-10 promoter polymorphisms by direct sequencing. RESULTS: Our analysis did not reveal differences in the distribution of the 15 SNPs between allergic patients and controls. However, among atopic subjects, we found two distinct significant associations between immediate beta-lactam allergy in women and the Ile75Val variant of IL-4Ralpha gene (P = 0.012, OR = 5.4, CI: 1.16-27.7), and two linked IL-10 promoter gene polymorphisms, -819C>T and -592 C>A (P = 0.023, OR = 17.5, CI: 1.26-533.07). In contrast, we observed no association in allergic male subjects in the atopic population. Interestingly, the IL-4Ralpha Ile75Val variant could have a paradoxal protective effect in atopic male patients (P = 0.004, OR = 0.07, CI: 0.01-0.66). CONCLUSION: Our findings suggest that polymorphisms in the IL-10 promoter and IL-4Ralpha genes are genetic factors that favour beta-lactam immediate allergies in female patients with atopy.

The presence of dominant T-cell clones in peripheral blood of patients with collagen vascular disorders: a prospective study of 97 cases.

BACKGROUND: T-lymphocyte dysfunction has been seldom investigated in collagen vascular disorders. The search for dominant T-cell clones has been scarcely reported, although the presence of such clones might be expected in disorders showing immune responses directed against a variety of autoantigens. OBJECTIVES: We conducted a systematic search for dominant T-cell clones in peripheral blood in patients with collagen vascular disorders. Patients and methods Ninety-seven patients with collagen vascular disorders were studied (7 cutaneous and 38 systemic lupus erythematosus; 8 multiple morphea; 12 regional scleroderma; 32 systemic sclerosis of the CREST type). A dominant T-cell clone was searched for in peripheral blood by polymerase chain reaction targeting the T-cell receptor gamma chain followed by a size analysis of amplified fragments. Peripheral blood from patients with nonlymphocyte-dependent disorders and matched by age and sex was assessed in the same conditions. Results in both groups were compared using nonparametric statistical tests. RESULTS: Overall, a circulating dominant T-cell clone was found in 52% of patients compared with 16.9% in controls. More precisely, such a dominant clone was present in 43% and 37% of cutaneous and systemic lupus erythematosus, respectively, in 75% of multiple morphea, 75% of regional scleroderma and 60% of CREST syndrome patients. The percentages in all subsets of patients were significantly higher than in the control group. CONCLUSIONS: The presence of a dominant T-cell clone in peripheral blood is significantly more frequent in collagen vascular disorders than in controls, especially in patients with scleroderma, whatever the clinical subset, which suggests T-cell involvement in the immune response dysfunction in these diseases classically characterized by disturbances of B lymphocytes. The relevance of such a dominant clone regarding diagnosis, pathomechanisms, long-term outcome and visceral prognosis of these diseases as well as therapeutic decisions remains to be evaluated.

HLA-DMA*0103 and HLA-DMB*0104 alleles as novel prognostic factors in rheumatoid arthritis.

OBJECTIVE: To evaluate HLA-DM alleles as markers for disease severity in rheumatoid arthritis (RA). METHODS: Two distinct cohorts of patients with RA were oligotyped for HLA-DB1 and HLA-DM genes using PCR amplified genomic DNA with sequence specific oligonucleotide probes. Cohort 1 comprised 199 unselected patients with RA (mean (SD) age 45.5 (13.5) years; disease duration 11.9(8.8) years), whose disease severity was assessed using Larsen score on hand and foot radiographs. Cohort 2 comprised 95 patients with severe RA and 70 patients with benign RA according to the Larsen method. RESULTS: In cohort 1, after stratification according to DRB1 genotypes, patients positive for HLA-DMA*0103 and negative for HLA-DRB1*04 tended to have greater articular damage on hands and wrists (p = 0.07 by Mann-Whitney U test) and reached statistical significance for the Larsen score per year (p = 0.05). This association between HLA-DMA*0103 and articular damage was especially observed in patients with HLA-DRB1*01. Similarly, HLA-DMB*0104 positive patients had higher Larsen score on hands and wrists (p = 0.02). This association was even stronger in DRB1*04 positive patients (p = 0.005). In cohort 2, HLA-DMA*0103 was associated with severe RA in patients negative for HLA-DRB1*04 (OD = 5.4; p = 0.014). HLA-DMB*0104 allele frequency tended to be higher in patients with severe RA but without reaching significance. CONCLUSION: This is the first study evaluating the role of HLA-DM genes in the severity of RA. Our results suggest that HLA-DMA*0103 and HLA-DMB*0104 alleles may represent new genetic markers of RA severity. The HLA-DMA*0103 allele tends to be associated with patients with RA negative for DRB1*04 and could predict a more severe form of disease especially in HLA-DRB1*01 positive patients. The HLA-DMB*0104 allele could have an additive effect in HLA-DRB1*04 patients. Combined determination of HLA-DM and HLA-DRB1 alleles could facilitate identification of patients likely to have a poor disease course.

Reduced intensity conditioning: enhanced graft-versus-tumor effect following dose-reduced conditioning and allogeneic transplantation for refractory lymphoid malignancies after high-dose therapy.

Non-myeloablative regimens have been proven to allow engraftment following allogeneic stem cells transplantation (allo-SCT) with minimal procedure-related toxicity. Conventional allo-SCT may produce remissions in patients with relapsed and refractory lymphoid malignancies (LM) but these good results may be achieved at the cost of high treatment-related morbidity and mortality. Application of allo-SCT using less intensive regimens may temper the frequency of these complications, allowing a potent graft-versus-tumor effect (GVT). We present our data on 11 patients with LM receiving allo-SCT with a reduced regimen. Ten patients had received previous high-dose therapy, and were at high risk for toxicity, thus precluding the use of allo-SCT. A fludarabine and low-dose busulfan combination facilitated engraftment while exerting GVT. Hematological recovery was quick, and full donor T cell chimerism preceded acute GVHD. GVHD and infections were the major problems. Spontaneous acute GVHD occurred in eight patients (72%). Five patients (45%) achieved complete remission, and the GVT effect was closely associated with GVHD. These results support the concept that GVT is effective against LM in patients who have been heavily pretreated. Further studies are needed to investigate strategies to generate more specific alloreactive effects providing optimal GVT and an acceptable risk of GVHD and infections.

CD4 T cell surface CCR5 density as a host factor in HIV-1 disease progression.

OBJECTIVE AND DESIGN: We have recently shown that the number of CCR5 molecules at the surface of peripheral blood CD4 T cells (CCR5 density) correlates with the viral RNA plasma level in HIV-1-infected individuals. As viral load is a strong predictor of outcome in HIV infection, the present study examines the correlation between CCR5 density and HIV-1 disease progression. METHODS: Using a quantitative flow cytometry assay, we measured CCR5 density in HIV-1-infected adults and control healthy volunteers. The CCR5 genotype (presence of a Delta 32 allele) was also determined. RESULTS: CCR5 density was stable over time on non-activated, HLA-DR(-)CD4 T cells of infected individuals. In a study cohort of 25 patients, asymptomatic and non-treated, we observed a correlation between CCR5 density on HLA-DR(-)CD4 T cells and the CD4 T cell slope (P = 0.026), which was independent of the presence or absence of the Delta 32CCR5 deletion. In particular, slow progressors expressed lower CCR5 densities than non-slow progressors (P = 0.004) and non-infected control subjects (P = 0.002). CONCLUSION: These results are compatible with the hypothesis that CCR5 density, which is a key factor of HIV-1 infectability, determines in-vivo HIV production, and thereby the rate of CD4 cell decline. Consequently, CCR5 density quantitation could be a new valuable prognostic tool in HIV-1 infection. Moreover, these data emphasize the therapeutic potential of treatments that reduce functional CCR5 density.

Prognostic factors for radiographic damage in early rheumatoid arthritis: a multiparameter prospective study.

OBJECTIVE: To determine prognostic factors of radiologic damage and radiologic progression in early rheumatoid arthritis (RA). METHODS: A cohort of 191 patients with RA whose disease duration was shorter than 1 year were prospectively followed up for 3 years. Radiologic scores (as determined by Sharp's method, modified by van der Heijde) and radiologic progression were used as outcome measures. Numerous baseline clinical, laboratory, genetic, and radiographic data were obtained. RESULTS: The change in the total radiologic score for the patients followed up over 3 years was a mean +/- SD increase of 6.1 +/- 6.2. Radiologic progression was observed in 71 of the 172 patients for whom there were data at the end of the study. By univariate analysis with Fisher's exact test, radiologic scores and progression at followup were closely correlated with the baseline values of the erythrocyte sedimentation rate (ESR), C-reactive protein level, IgM and IgA rheumatoid factor positivity, antiperinuclear antibody positivity, radiologic scores, duration of morning stiffness, and RA-associated HLA-DRB1*04 genes. No correlation was demonstrated with sex, age, Disease Activity Score, swollen or tender joint counts, extraarticular manifestations, Health Assessment Questionnaire score, Ritchie Articular Index, patient's assessment of pain, positivity for anti-heat-shock protein 90-kd antibodies, anticalpastatin antibodies, anti-RA33 antibodies, antinuclear antibodies, YKL-40, or antikeratin antibodies, and HLA-DRB1*01 genes. The logistic regression analysis revealed that the only baseline values that were predictive of the 3-year radiologic scores were IgM rheumatoid factor positivity, DRB1*04 genes, pain score, and total radiologic score. Progression of joint damage was predicted by the ESR, IgM rheumatoid factor positivity, DRB1*04 genes, and erosions score at baseline. CONCLUSION: Prognostic factors for radiographic damage in early RA were identified. A combination of these baseline values allowed us to draw up a predictive arithmetic score that could be used to predict radiologic damage at 3 years and radiologic progression in individual patients.