Welcome to the Autoimmunity 2021 Congress Calendar

Background and Aims

Graft Vs Host disease (GvHD) remains the Achilles’ heel of hematopoietic stem cell transplantation: GvHD elicit patient 's risk for transplant-related mortality and decreased quality of life while treduced GvHD increase the risk of relapse.While GvHD is T cell mediated, the APCs are required for the initiation and maintenance of the GvHD. To reduce the risk for GvHD, grafts are sometimes depleted of their T cells, however, while preventing GvHD, the critically important attributes of rate and pace of engraftment and the graft versus leukemia (GvL) effect are reduced significantly. Novel strategies that aim to abrogate or ameliorate GvHD, while preserving engraftment and GvL are of great need.

Methods

A short incubation (2hr) of G-CSF mobilized PBCs with multimeric Fas ligand (i.e. ApoGraft) selectively induces apoptosis in T cell subsets and to a lesser degree in B cells and APCs, but not in CD34+ progenitor cells. FasL treatment preferentially induces apoptosis in mature T cell subsets which express high levels of Fas (CD95) as well as the pro-inflammatory T cell subtypes TH1 and TH17 cells, while no apoptotic signal is detected in Tregs and hematopoietic progenitor cells.

Results

In preliminary studies we tested the In-Vivo effect of FasL treated BMT in the context of diabetes type I and Osteoarthritis as two autoimmune models.

Conclusions

After initiating human trials in USA and Israel, Cellect is looking for the next indications where FasL Ex-Vivo treatment of Apheresis products can be adopted. Data and opportunities for this breakthrough technology will be presented.

Background and Aims

Mesenchymal stromal cells (MSC) exert immunomodulatory and regenerative effects by releasing paracrine mediators including extracellular vesicles (EV), nanoparticles involved in cell-to-cell communication through transfer of proteins, mRNA and microRNA. The aim of this in vitro study was the evaluation of MSC-EV in T regulatory cell (Treg) generation and inhibition of glomerular cell alterations observed in lupus nephritis (LN).

Methods

EV were characterized for size, protein and RNA content after MSC supernatant ultracentrifugation. The effects of EV were studied on: 1) T cells isolated from peripheral blood and co-cultured with B cells purified by spleen of matched donors; 2) human glomerular endothelial and mesangial cells cultured in presence of anti-dsDNA containing sera drawn from LN patients.

Results

MSC-EV sized 60-150 nm and carried different microRNA and mRNA including the immunoregulatory Foxp3, Tim-1 and thrombospondin-1. EV were internalized in T cells inhibiting proliferation induced by PHA/ionomycin or by co-culture with spleen-derived B cells. EVs horizontally transferred to T cells Foxp3 mRNA inducing a Treg phenotype: EV-induced Tregs decreased T cell proliferation. MSC-EV also induced a regulatory phenotype in B cells (increased Tim-1 expression). EV were internalized in glomerular endothelial and mesangial cells inducing a significant decrease of LN sera-associated alterations. Indeed, MSC-EV reduced the release of TNF-alpha, IL-6 and MCP-1, endothelial-to-mesenchymal transition, inflammatory cell adhesion and fibrosis.

Conclusions

MSC-EV exert tolerogenic and regenerative effects by inhibiting T cell proliferation, inducing T/B cell regulatory phenotypes and protecting glomerular cells from LN sera-associated injury. MSC-EV could be evaluated as therapeutic strategy in LN and other autoimmune diseases.

Background and Aims

The chemokine receptor CCR9 play important role in the migration of immune cells in the gut and shows a strong clinical association in inflammatory bowel disease (IBD). Several clinical trials were conducted by targeting CCR9 or its ligand CCL25 in IBD but failed. The detailed cellular and mechanism of CCR9 and CCL25 interactions and its effect various immune cells are not clearly understood.

Methods

Gut inflammation in C57BL/6 mice was induced by giving dextrans sodium sulfate (DSS; 2% w/v) in the drinking water. Dendritic cells (DC) subsets and CD4 T cells were characterized using flow cytometry. Naive CD4⁺CD25^-CD44^- T cells were in vitro differentiated into Th17 and Treg cells in the presence of CCR9⁺ or CCR9^- DCs and recombinant CCL25.

Results

DSS treatment significantly increased the infiltration of CCR9⁺DCs in the gut-associated lymphoid tissues (GALT) compared to control mice. Among the CCR9⁺CD11c⁺DCs, the frequency of CD11b^-CD103⁺ DCs was significantly higher in the GALT. CCR9⁺ DCs showed lower expression of MHC II and CD86 molecules, and higher FasL and latency associated peptides in the GALT. CCR9⁺DCs in the presence of purified recombinant CCL25 promoted the differentiation of Foxp3⁺ regulatory CD4 T cells in the culture. The differentiation of Foxp3⁺Tregs was due to thymic stromal lymphopoietin (TSLP) produced by DCs in the culture. Furthermore, the adoptive transfer of CCR9⁺DCs in C57BL6 mice suppresses the ova-specific gut allergic response.

Conclusions

Our data showed that CCR9⁺DCs have a regulatory function and may be exploited as a cellular therapy to control gut inflammation and autoimmunity.

Background and Aims

Sarcoidosis is one of granulomatous diseases. Granuloma formation is a result of lymphocytes activation. In different studies the changes in B cells and T cells subsets in blood and broncho-alveolar fluid were found. Alteration of B cells and T cells subsets might be the result of T follicular helpers (Tfh) activity. Nowadays there is no data about the role of T follicular helpers in sarcoidosis.

The aim of this study was to determine the peripheral blood Tfh in patients with sarcoidosis.

Methods

In a prospective comparative study conducted in 2016-2018 we analyzed peripheral blood circulating Tfh cell subsets in 34 patients with first diagnosed sarcoidosis and 30 healthy donors using multicolor flow cytometry. The statistical comparisons of data were performed using the Mann–Whitney U test and ROC analysis with GraphPad Prism Version 6.0 (USA).

Results

According to Mann-Whitney U test in sarcoidosis patients in comparison with healthy subjects the level of Tfh1 in effector and central memory was found to be decreased and the level of Tf2, Tfh17 increased (p<0.01). According to the ROC analysis the difference significant for diagnostic purpose wasn`t found (AUC ≤0.7).

Conclusions

In sarcoidosis group were found an increase of Tfh2 and Tfh17 cells, that induce antibody secretion in B cells, and a decrease in Tfh1 cells, that regulate the apoptosis of B cells. This results might be the additional confirmation of autoimmune origin of sarcoidosis.

Background and Aims

Basophils are rare granulocytes, and mediate Th2 responses and B cell differentiation. Basophils are also implicated in the pathogenesis of various allergic, autoimmune and inflammatory diseases. Therefore, considering the impact of dysregulated functions of basophils in various diseases, it is essential to understand the regulatory mechanisms by which basophils are kept in check. As regulatory T cells (Tregs) are well known for the maintenance of immune tolerance, we sought to explore the role of human Tregs on basophils function.

Methods

CD4⁺CD25⁺ FoxP3⁺ Tregs and basophil were isolated from the buffy bags of healthy donors or human spleen. The interaction between basophils and Tregs was investigated by the analyses of surface markers, intracellular signaling molecules, release of cytokines and histamine. Blocking experimens were performed to explore the mechanisms.

Results

In contrast to the central dogma on Tregs as immunosuppressors, we discovered that human basophils are refractory to Treg-mediated suppression. On the contrary, we found that Tregs stimulate resting basophils to induce the expression of activation markers CD69, CD203c, and CD13, and release cytokines IL-4, IL-8, and IL-13. Mechanistically, Treg-induced activation of basophils involves IL-3 and STAT5.

Conclusions

Our results provide evidence of direct positive effects that human Tregs have on basophil activation and reveal a previously unrecognized feature of this cell subset well known for immunosuppressive functions. These fundamental findings have broad implications in the immunotherapy and management of allergic diseases.

Ref: 1) Sharma et al. Sci Immunol. 2018;3:eaan0829; 2) Stephen Victor et al. Haematologica. 2017;102:e233-e237; 3) Sharma & Bayry. Nat Rev Rheumatol. 2015;11:129-31.

Background and Aims

Oxidized 1-palmitoyl-2-arachidonoyl-sn-glycerol-3-phosphoryocholine (Ox-PAPC) is a major phospholipid in oxidized LDL (increased in atherosclerosis and other autoimmune diseases including SLE.) Such lipids are increased in autoimmune disease as SLE and associated with disease activity and cardiovascular disease. Here, we studied the effect of Ox-PAPC on immune activation in connection with atherosclerosis and autoimmunity.

The aim is to investigate how oxidized lipids can contribue to autoimmunity.

Methods

Macrophages and T-cells from human peripheral blood or atherosclerotic plaques were stimulated with Ox-PAPC in absence or presence of mitochondrial reactive oxygen species inhibitor (mito tempo) or glutathione (GSH) inhibitor (BSO). phosphatidylcholine (PTC), GSH or oxidized glutathione (GSSG) were measured from plasma. Immune activation, apoptosis, ROS production, heat shock protein 60 (HSP60), IL-1 beta, and mitochondrial membrane potential were measured by flow cytometry and/or ELISA. The level of GSH or GSSG and phosphatidylcholine in cells or plasma of atherosclerotic patients was measured by colorimetric and fluorometric kit.

Results

Ox-PAPC induced a pro-inflammatory type of T-cell activation but also induced apoptosis at a higher concentration. The Ox-PAPC-induced-activation and apoptosis of T-cells was inhibited by the mito tempo, and the mito tempo or BSO inhibited inflammatory macrophage activation. Furthermore, mitochondrial membrane potential was increased in macrophages but not in T cells. The level of PTC, GSH and GSSG were significantly higher in atherosclerotic patients as compared to control groups.

Conclusions

OxPAPC is a cause of proinflammatory activation of T cells through a direct mechanism and of macrophages in atherosclerotic plaques. Inhibition of OxPAPC could be useful to maintain plaque stability.

Background and Aims

Chronic glomerulonephritis (CGN) with nephrotic syndrome (NS) is a disease with high activity of immune inflammation. An imbalance of proinflammatory and anti-inflammatory mediators may underlie the progression of CGN. Aim: to determine the clinical significance of the Th17, Th1, and Treg cytokines to assess the activity and progression of CGN.

Methods

The study included 98 patients with CGN. The laboratory data were compared with the clinical and histological features of nephritis activity. The levels of IL-6, IL-10, IL-17, tumor necrosis factor α (TNFα) in the urine were determined using ELISA. The number of FoxP3-positive cells in the inflammatory interstitial infiltrate of the cortical layer was determined using immunohistochemistry.

Results

There was an increase in the levels of Th17, Th1, and T reg cytokines in urine - TNFα and IL-10 in patients with CGN, compared with healthy individuals. An imbalance between the proinflammatory cytokines (TNF-α, IL-6 and IL-17A) and anti-inflammatory factors (IL-10 and Treg in the tissue) in patients with NS was demonstrated. There was a decrease in the number of T-reg cells in the interstitium of the kidney and a decrease in the production of IL-10 in CGN patients with NS, compared with patients without NS. The most pronounced changes in the cytokine profile were observed in patients with focal segmental glomerulosclerosis (FSGS).

Conclusions

The data indicate that cytokine imbalance was the most pronounced in the activation of IL-17 and TNF-α; a decrease in the regulatory anti-inflammatory link (Treg) in the kidney tissue was observed in FSGS, the most severe form of CGN.