OP0231 MASS CYTOMETRY DATA RECLASSIFY SYSTEMIC AUTOIMMUNE DISEASE PATIENTS IN PHENOTYPICALLY DISTINCTIVE GROUPS

Background

Systemic lupus erythematosus (SLE), rheumatoid arthritis (RA), systemic sclerosis (SSC), Sjögren’s syndrome (SJS), mixed connective tissue disease (MCTD), primary antiphospholipid syndrome (PAPS) and undifferentiated connective tissue disease (UCTD) are classified as systemic autoimmune diseases (SADs). They are diagnosed based on different clinical and laboratory criteria. Due to their high internal heterogeneity and overlapping symptoms, SADs are difficult to diagnose. Therefore, molecular and cellular-based studies need to be undertaken to precisely classify the patients. Mass cytometry is a single-cell proteomics technology that measures approximately 50 markers per cell, thus it is a suitable tool to perform deep-phenotyping studies in SADs.

Objectives

Explore differences and similarities between SADs and build reclassification framework using high-dimensional cytometry data.

Methods

The whole blood samples collected from 129 individuals, including patients and controls were stained with a 39-plex antibody panel and acquired in 9 batches on a CyTOF (HELIOS) instrument. Data were cleaned, and normalized for batch effects using semi-automated cytof analysis pipeline. Cell frequencies and median signal intensities (MSI) for each population were extracted using FlowSOM for mononuclear cells (PBMC) and Phenograph for granulocytes. Secretion of 44 cytokines and chemokines were analyzed using a multiplexed luminex assay. Diseases were compared by Kruskal-Wallis analysis and hierarchical clustering and reclassification was done using unsupervised k-means clustering. Cytokine analysis across clusters was performed using Kruskal-Wallis test.

Results

Differently expressed features were observed between patient groups, regarding frequency of classical monocytes, B and T cells subpopulations, mature and immature granulocytes and intensities of CD38, HLA-DR and CD95 across various populations. However, none of them were disease specific. K-means clustering identified four patient clusters, which were composed by a mixture of different diagnosis. Cluster C1 was characterized by increased levels of circulating cells from PBMC compartment, and lower activation of different populations of the T cell compartment. It presented lower frequency in multiple granulocyte populations and the highest expression of CD95 and CD38. This cluster was also associated with antimalarial and steroid treatment. Clusters C1 and C2 were exactly opposite to each other, cluster C3 was characterized by intermediate features between C1 and C2 and cluster C4 could be considered as undifferentiated, mixed group. Higher production of TNFα, IL-10 and IP-10 were found in patients from C1 compared to C2, suggesting more active phenotype in C1 and physiological one in C2. The cytokine levels were independent of the treatment.

Conclusion

We constructed a patient reclassification framework using cell frequencies and expression levels of functional markers. To our knowledge this is the first time when 7 different SADs were compared using mass cytometry. In agreement with other reports we did not detect any disease-specific cellular markers. Distribution of diagnosis across different clusters confirms diseases heterogeneity. Patients can be classified into phenotypically similar groups, that could potentially benefit from the same line of treatment.

Acknowledgements

This project has received funding from the Innovative Medicines Initiative 2 Joint Undertaking (JU) under grant agreement No 831434 (3TR) and The JU receives support from the European Union’s Horizon 2020 research and innovation programme and EFPIA. Also from No 115565 PRECISESADS.

Disclosure of Interests

None declared

Benznidazole treatment reduces the induction of indoleamine 2,3-dioxygenase (IDO) enzymatic activity in Chagas disease symptomatic patients

The enzyme indoleamine 2,3-dioxigenase (IDO) is critical for the regulation of immune responses in pro-tolerogenic antigen-presenting cell. To address the profile of immune responses associated with Chagas disease, we measured IDO activity of peripheral blood mononuclear cells from 168 chronic patients and 13 healthy donors. We found that IDO activity was increased in patients with Chagas disease when compared with controls. Moreover, the IDO activity of patients with Chagas disease in the symptomatic chronic phase, involving cardiac or digestive alterations, was higher than that detected in asymptomatic patients and correlated with the severity of the symptoms. Furthermore, benznidazole treatment induced a long-lasting decrease in IDO activity in symptomatic patients, reaching levels comparable with those of healthy donors. These results suggest that a pro-tolerogenic state is associated with the severity of Chagas disease and that benznidazole treatment is a valuable tool for breaking the parasite-driven immune tolerance in the symptomatic chronic phase of Chagas disease.

Differential CD86 and CD40 co-stimulatory molecules and cytokine expression pattern induced by Trypanosoma cruzi in APCs from resistant or susceptible mice

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Trypanosoma cruzi heat-shock protein-70 kDa,alone or fused to the parasite KMP11 antigen, induces functional maturation of murine dendritic cells

We analyse the effect of Trypanosoma cruzi heat-shock protein-70 (HSP70) on the maturation of murine dendritic cells (DC)generated from bone marrow precursor cells. The results obtained show that HSP70, both alone and fused to the KMP11 antigen, as well as a HSP70 fragment, is capable of maturing murine DC. Mature DC have enhanced expression of IL12, TNF-alpha cytokines, costimulation molecules and activation markers, showing a clear increase in the allostimulatory capacity. These findings suggest that T. cruzi HSP70 may be a very useful vehicle for developing DC-based immunoprophylaxis and therapy against infections.

The immunization of A2/K(b) transgenic mice with the KMP11-HSP70 fusion protein induces CTL response against human cells expressing the T. cruzi KMP11 antigen: identification of A2-restricted epitopes

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Mapping of the antigenic determinants of the T. cruzi kinetoplastid membrane protein-11. Identification of a linear epitope specifically recognized by human Chagasic sera

The high variability among strains and isolates of Trypanosoma cruzi and the existence of shared antigenic determinants with other pathogens, particularly with members of the Leishmania genus make difficult the specific diagnosis of Chagas' disease. The data reported in this paper show that the T. cruzi KMP11 protein is an immunodominant antigen highly recognized by the sera from chagasic and leishmaniasis patients. By the use of amino- and carboxyl-terminal truncated KMP11 recombinant proteins and synthetic peptides, evidence is provided that while the sera from chagasic patients recognize linear peptides the sera from patients with visceral leishmaniasis must be predominantly directed against conformational epitopes. We found that a particular linear determinant, located in the carboxyl-terminal region of the protein, is recognized with high specificity and sensitivity only by sera from Chagas' disease patients, suggesting it could be a good candidate for differential serodiagnosis of Chagas' disease.

HSP70 from Trypanosoma cruzi is endowed with specific cell proliferation potential leading to apoptosis

The Trypanosoma cruzi HSP70 recombinant protein has the capacity to stimulate splenocytes or lymph node cells from naive mice in a non-haplotype-restricted way. The proliferative response is abolished by proteinase K digestion and by specific anti-HSP70 antibodies. The induced stimulation index was maximal after 24 h of incubation with the protein. This stimulation leads to cell death in a Fas-Fas ligand-independent way. The phenotype of the expanded cells was CD3(+) TCRalphass(+) CD4(+). HSP70-responsive cells express a broad range of cytokines including IFN-gamma, IL-2 and tumor necrosis factor-alpha. After 48 h of incubation with HSP70 there was a significant increase in relative intracellular levels of CD3 TCRalphass receptors. The expanded CD4(+) cell population expressed CD25; however, in contrast to concanavalin A-treated culture, delayed CD44 expression was observed.

Plasticity of the histone H2A genes in a Brazilian and six Colombian strains of Trypanosoma cruzi

The analysis of three recombinant clones containing the histone H2A locus isolated from a genomic library of Trypanosoma cruzi DNA shows that the H2A gene loci are formed by 1.2 and 0.76 kb long intercalated units organized in a head-to-tail tandem array. The difference in length between the two gene units is due to the presence of a short interspersed nucleotide element (SINE)-like DNA sequence inserted at the 3' end of some of these units. Southern, northern and chromosomal blot analysis of a Brazilian Y strain and six Colombian strains demonstrated the existence of polymorphisms regarding the relative copy number of the H2A gene units, the relative abundance of the H2A transcripts and their chromosomal location. These results show the existence of a dynamic organization in the H2A loci among T. cruzi strains in which a SINE-like sequence may be involved and support the fact that T. cruzi has a high degree of plasticity in its genome.

The stability and maturation of the H2A histone mRNAs from Trypanosoma cruzi are implicated in their post-transcriptional regulation

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Phage recovery by electroporation of naked DNA into host cells avoids the use of packaging extracts

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Control mechanisms of the H2A genes expression in Trypanosoma cruzi

In a previous report we have described that the T. cruzi histone H2A gene is encoded in two independent gene clusters located in a single chromosome. In the present paper we show that both gene cluster are actively transcribed as two sized classes of polyadenylated mRNAs demonstrating, moreover, the existence of alternative splicing sites and microheterogeneities at the polyadenylation site. We also describe that while the expression of the H2A genes in the non replicative trypomastigote forms is only residual, in the replicative forms there is constitutive transcription of these genes and that the transcription is not associated to DNA replication. The data show, moreover, that in the replicative forms the steady state levels of the H2A mRNAs are controlled at a post-transcriptional level which is associated to DNA replication.

Identification of a Trypanosoma cruzi antigenic epitope implicated in the infectivity of fibroblast LLC-MK2 cells

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Multiprimer PCR system for differential identification of mycobacteria in clinical samples

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Characterization of a non-long terminal repeat retrotransposon cDNA (L1Tc) from Trypanosoma cruzi: homology of the first ORF with the ape family of DNA repair enzymes

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