AB0068 INTERLEUKIN 40 SERUM LEVELS ARE ELEVATED IN PATIENTS WITH EARLY RHEUMATOID ARTHRITIS AND ASSOCIATE WITH NEUTROPHIL ACTIVATION

Background

IL-40 is a newly described cytokine associated with immune system function and malignant transformation. We have recently shown that IL-40 is up-regulated in rheumatoid arthritis (RA) and associates with disease activity, autoantibodies and NETosis1.

Objectives

As autoantibodies and neutrophil activation are factors thought to drive the pathological processes at early phase of RA development, we aimed to investigate IL-40 in relation to neutrophils and early stages of RA (ERA).

Methods

The levels of serum IL-40 were determined in a cohort of treatment naïve patients with ERA at baseline (n=60) and three months after initiation of conventional treatment (n=60). Serum IL-40 was also determined in sex- and age- matched healthy controls (n=60). Levels of IL-40, cytokines and NETosis markers (proteinase 3, PR3 and neutrophil elastase, NE) were measured by commercially available ELISA kits. The levels of autoantibodies were analysed by routine laboratory techniques. In vitro experiments were performed on peripheral blood neutrophils from patients with ERA (n=15).

Results

Levels of IL-40 were elevated in ERA patients at baseline compared to healthy controls (p<0.0001) and normalised after three months of the treatment (p<0.0001). Baseline serum IL-40 was associated with the levels of autoantibodies RF (IgM) (p<0.01) and anti-CCP (p<0.01) and markers of NETosis PR3 and NE) (both p<0.0001). Moreover, significant decreases in the serum IL-40 following the therapy correlated with the decrease of NETosis markers PR3 (p<0.01) and NE (p<0.05). In vitro, neutrophils from patients with ERA significantly enhanced the release of IL-40 following NETosis induction (p<0.05) or after exposure to pro-inflammatory cytokines such as IL-1β, IL-8 (p<0.05), TNF (p<0.01) or to LPS (p<0.05). Lastly, recombinant IL-40 induced the secretion of IL-1β (p<0.05) and TNF (p<0.05) by ERA neutrophils.

Conclusion

We demonstrated for the first time that IL-40 is upregulated in ERA and decreases after three months of conventional therapy. Moreover, we showed that neutrophils are an important source of IL-40 in RA and its release is potentiated by pro-inflammatory cytokines and NETosis. Our results suggest that IL-40 may play an important role in early stages of RA.

References

[1]Navrátilová A, Andrés Cerezo L, Hulejová H, Bečvář V, Tomčík M, Komarc M, et al. IL-40: A New B Cell-Associated Cytokine Up-Regulated in Rheumatoid Arthritis Decreases Following the Rituximab Therapy and Correlates With Disease Activity, Autoantibodies, and NETosis. Front Immunol. 2021 Oct 21;12:745523. doi: 10.3389/fimmu.2021.745523.

Acknowledgements

Supported by AZV-NU21-05-00276, MHCR 023728, SVV 260 523 and BBMRI-CZ LM2018125

Disclosure of Interests

None declared

IL-40: A New B Cell-Associated Cytokine Up-Regulated in Rheumatoid Arthritis Decreases Following the Rituximab Therapy and Correlates With Disease Activity, Autoantibodies, and NETosis

Background

Interleukin 40 (IL-40) is a newly identified B cell-associated cytokine implicated in humoral immune responses and B cell homeostasis. As B cells play a pivotal role in autoimmunity, we investigated the function of IL-40 in rheumatoid arthritis (RA).

Methods

IL-40 expression was determined in the synovial tissue from RA and osteoarthritis (OA) patients. IL-40 was analysed in the serum/synovial fluid of patients with RA (n=50), systemic lupus erythematosus (SLE, n=69), OA (n=44), and healthy controls (HC, n=50). We assessed the changes of IL-40 levels in RA patients following the B cell depletion by rituximab (n=29) or after the TNF inhibition by adalimumab (n=25). We examined the relationship between IL-40, disease activity, autoantibodies, cytokines, and NETosis markers. Effect of IL-40 on synovial fibroblasts was determined.

Results

IL-40 was overexpressed in RA synovial tissue, particularly by synovial lining and infiltrating immune cells. The levels of IL-40 were up-regulated in the synovial fluid of RA versus OA patients (p<0.0001). Similarly, IL-40 was increased in the serum of RA patients compared to HC, OA, or SLE (p<0.0001 for all) and decreased after 16 and 24 weeks (p<0.01 and p<0.01) following rituximab treatment. No significant effect of adalimumab on IL-40 was observed. IL-40 levels in RA patients correlated with rheumatoid factor-IgM and anti-cyclic citrullinated peptides (anti-CCP) in the serum (p<0.0001 and p<0.01), as well as in the synovial fluid (p<0.0001 and p<0.001). Synovial fluid IL-40 was also associated with disease activity score DAS28 (p<0.05), synovial fluid leukocyte count (p<0.01), neutrophil attractants IL-8 (p<0.01), MIP-1α (p<0.01), and markers of neutrophil extracellular traps externalization (NETosis) such as proteinase 3 (p<0.0001) and neutrophil elastase (p<0.0001). Synovial fibroblasts exposed to IL-40 increased the secretion of IL-8 (p<0.01), MCP-1 (p<0.05), and MMP-13 (p<0.01) compared to the unstimulated cells.

Conclusions

We show the up-regulation of IL-40 in RA and its decrease following B cell depleting therapy. The association of IL-40 with autoantibodies, chemokines, and markers of NETosis may imply its potential involvement in RA development. Moreover, IL-40 up-regulates the secretion of chemokines and MMP-13 in synovial fibroblasts, indicating its role in the regulation of inflammation and tissue destruction in RA.

POS0388 INTERLEUKIN 40 (IL-40) IS UP-REGULATED IN RHEUMATOID ARTHRITIS (RA) AND ASSOCIATED WITH DISEASE ACTIVITY, LEVELS OF AUTOANTIBODIES AND CHEMOKINES

Background:

Interleukin 40 (IL-40) is newly identified B cell - associated cytokine implicated in humoral immune responses and in B cell development. As B cells play a pivotal role in autoimmunity, we aimed to investigate the function of IL-40 in rheumatoid arthritis (RA).

Objectives:

The aim of our study was to determine the function of IL-40 in RA.

Methods:

IL-40 expression in the synovial tissue was determined by immunohistochemistry and immunofluorescence (n=4-5). IL-40 was analysed in the serum/synovial fluid of patients with RA (n=69), systemic lupus erythematosus (SLE; n=69), osteoarthritis (OA; n=44), and in healthy controls (HC; n=25). Given the association of IL-40 with B cells, we analysed the effect of rituximab therapy on the serum IL-40 in 19 patients with RA after 16 and 24 weeks of the therapy. The clinical activity of patients with RA was assessed according to the 28 joint count Disease Activity Score (DAS28). Levels of C-reactive protein (CRP) and autoantibodies were measured by routine laboratory techniques. In vitro experiments were performed in RA synovial fibroblasts (n=9). Levels of cytokines and inflammatory mediators were determined in serum, synovial fluid and supernatants using ELISA or multiplex immunoassay.

Results:

IL-40 was overexpressed in RA synovial tissue compared to OA, particularly by synovial fibroblasts and immune cells such as B and T lymphocytes, macrophages and neutrophils. The levels of IL-40 were significantly higher in the synovial fluid of RA patients compared to OA (33.2 (6.6-68.9) vs. 0.7 (0.1-2.4) ng/ml; p<0.0001). In addition, IL-40 was increased in the serum of RA patients compared to SLE, OA or HC (4.8 (1.7-24.9) vs. 1.4 (1.0-1.9), 1.6 (0.6-3.1) or 1.5 (0.7-2.7) ng/ml; p<0.0001 for all) and decreased after 16 (p<0.01) and 24 weeks (p<0.001) in a subgroup of rituximab treated patients with RA. IL-40 levels in RA patients correlated with autoantibodies rheumatoid factor (IgM) and anti-citrullinated protein antibody (ACPA) in the serum (p<0.0001 and p<0.01) as well as in the synovial fluid (p<0.0001 and p<0.001). IL-40 in RA synovial fluid was also significantly associated with DAS28 (p<0.05), synovial fluid leukocyte count (p<0.01), number of swollen joints (p<0.05) and neutrophil attractants IL-8 (p<0.01) and MIP-1α (p<0.01). RA synovial fibroblasts exposed to recombinant IL-40 increased secretion of IL-8 (p<0.01), MCP-1 (p<0.05) and MMP-13 (p<0.01) compared to unstimulated cells in in vitro conditions.

Conclusion:

Our results show for the first time that IL-40 is elevated in RA and decreases following B-cell depletion therapy. The association of IL-40 with autoantibodies and chemokines may imply its potential involvement in RA development. Moreover, IL-40 up-regulates the secretion of chemokines and MMP-13 by synovial fibroblasts, indicating its role in the regulation of inflammation and tissue destruction in RA.

Acknowledgements:

Supported by MHCR 023728 a SVV 260 523

Disclosure of Interests:

None declared

POS1142 INTERLEUKIN-37: ASSOCIATIONS OF PLASMA LEVELS AND GENETIC VARIANTS IN GOUT

Background:

IL-37, recently characterized IL-1 family member, has anti-inflammatory effects by suppression of IL-1ß and other proinflammatory cytokines. In this study we investigated the effects of genetics variants in IL-37 link with IL-37 plasma levels in a cohorts of patients with hyperuricemia/gout.

Objectives:

The aim of this study was to determine the association of IL-37 gene polymorphism and plasma IL-37 levels in patients with hyperuricemia and gout.

Methods:

The cohorts consisted of 50 control subjects, 50 subjects of primary hyperuricemia, 50 subjects of primary gout, 28 subjects of tophaceous gout and 19 subjects of acute gout flare. The analyzed cohorts were selected from a previously reported set of 250 hyperuricemia/gout patients and 132 normouricemic subjects (1) according to the descending level of serum urate. All coding regions and intron-exon boundaries of IL-37, exon 1-5, were amplified and sequenced directly. Comparisons of presence/absence of identified variants was performed using P-values binomial test. Levels of plasma IL-37 were measured using Enzyme-Linked ImmunoSorbent Assay. All tests were performed in accordance with standards set by the institutional ethics committees, which approved the project in Prague (no.6181/2015).

Results:

We identified 12 IL-37 genetic variants: five intron (rs28947188, rs2466448, rs3811045, rs3811048, rs2708944), and seven non-synonymous allelic variants (rs3811046, rs3811047, rs2708943, rs2723183, rs2723187, rs2708947, rs27231927). Minor allele frequency (MAF) of those variants in European population from ExAC databases were used for comparison. Our data showed that the rs28947188, rs3811045, rs3811046, rs3811047, rs2723187, rs2708947, and rs27231927 variants were under-represented in the Czech hyperuricemia, gout, and tophaceous gout cohort compared with the control cohort and general European population (P = 0.0082 – 0.0395).

The levels of plasma IL-37 were significantly higher in patients with tophaceous gout compared to control subjects (P 0.0329) whereas no changes were observed in subjects with primary hyperuricemia, primary gout or acute gout flare compared to control subjects. However, IL-37 was elevated in cohorts of patients with gout, tophaceous gout and acute gout flare compared to primary hyperuricemia subjects (P 0.0198, 0.0005, 0.0099; respectively).

Conclusion:

Although further analyzes are needed to elucidate the role of IL-37 in the gout, our results show that genetic variants in anti-inflammatory cytokine IL-37 are probably implicated in the pathogenesis of gout.

References:

[1]Toyoda Y, et al. Functional characterization of clinically-relevant rare variants in ABCG2 identified in a gout and hyperuricemia cohort. Cells. 2019 Apr 18;8(4).

Acknowledgements:

This study was supported by the grant from the Czech Republic Ministry of Health RVO 00023728.

Disclosure of Interests:

None declared.

Long-range organization of plant satellite repeats investigated using strand-specific FISH

The technique of chromosomal orientation and direction fluorescence in situ hybridization (COD-FISH) was adapted for plant chromosomes in order to study long-range organization of two families of satellite repeats, VicTR-B of Vicia sativa and PisTR-B of Pisum sativum. The technique allowed FISH to be performed on mitotic chromosomes in a strand-specific manner, resulting in visualization of the repeat orientation along the chromosomes and with respect to the direction of telomeric repeats. The VicTR-B probe applied to V. sativa chromosomes produced signals on a single chromatid at most regions containing corresponding sequences, thus confirming a presence of long arrays of head-to-tail arranged repeat monomers which is typical for satellite DNA. However, hybridization signals of different or equal intensities on both chromatids were also detected at some loci, suggesting a more complex arrangement of the repeats. Similar observations were made for PisTR-B repeats on P. sativum chromosomes, although the proportion of loci displaying signals on both chromatids was lower. In contrast to VicTR-B, orientation of the PisTR-B clusters with respect to telomeric sequences appeared to be conserved among subtelomeric regions of metacentric chromosomes and of the short arms of acrocentric chromosomes.

Microarray-based survey of repetitive genomic sequences in Vicia spp

A modified DNA microarray-based technique was devised for preliminary screening of short fragment genomic DNA libraries from three Vicia species (V. melanops, V. narbonensis, and V. sativa) to isolate representative highly abundant DNA sequences that show different distribution patterns among related legume species. The microarrays were sequentially hybridized with labeled genomic DNAs of thirteen Vicia and seven other Fabaceae species and scored for hybridization signals of individual clones. The clones were then assigned to one of the following groups characterized by hybridization to: (1) all tested species, (2) most of the Vicia and Pisum species, (3) only a few Vicia species, and (4) preferentially a single Vicia species. Several clones from each group, 65 in total, were sequenced. All Group I clones were identified as rDNA genes or fragments of chloroplast genome, whereas the majority of Group II clones showed significant homologies to retroelement sequences. Clones in Groups III and IV contained novel dispersed repeats with copy numbers 10(2)-10(6)/1C and two genus-specific tandem repeats. One of these belongs to the VicTR-B repeat family, and the other clone (S12) contains an amplified portion of the rDNA intergenic spacer. In situ hybridization using V. sativa metaphase chromosomes revealed the presence of the S12 sequences not only within rDNA genes, but also at several additional loci. The newly identified repeats, as well as the retroelement-like sequences, were characterized with respect to their abundance within individual genomes. Correlations between the repeat distributions and the current taxonomic classification of these species are discussed.

Two new families of tandem repeats isolated from genus Vicia using genomic self-priming PCR

A modified genomic self-priming technique was used for rapid isolation of tandem repeats from several Vicia species. Based on homologies of their nucleotide sequences the newly isolated clones were assigned to two repeat families named VicTR-A and VicTR-B. Both families are rich in AT (74%) and are organized as long blocks of tandemly repeated units. The VicTR-A repeats are characterized by a monomer size of 69 bp, whereas the VicTR-B repeat monomer is about 38 bp long, and the two families do not share significant sequence homology. VicTR sequences show different degrees of amplification (up to 10(6)-10(7) copies/haploid genome) in individual Vicia species and are not amplified in other legumes. The abundances of these repeats do not correlate with genome sizes but are similar in species that belong to the same taxonomic section within the genus Vicia. Primed in situ (PRINS) labeling of metaphase chromosomes of V. pannonica revealed that VicTR-A sequences are located predominantly in the telomeric regions of the short arms of all chromosomes. In contrast, labeling of VicTR-B repeats in V. sativa resulted in mainly intercalary bands of various intensities and only weak telomeric signals.

[Our surgical approach in the treatment of otosclerosis over the past 10 years]

The most frequently used technique of surgery of otosclerosis used during the past ten years in the Central Military Hospital was Schuknecht's technique of wire and fat. 575 thus operated patients account for 89.4% of the total number of 643 operations. A compensation of the bone reserve to 0-10 dB was achieved in the late results of 56.3% of the operated patients, in another 30% there were auditory gains of speech frequencies, on average above 10 dB. Favourable late results were thus achieved in 86.3% of the operated patients, deterioration of hearing was recorded in 4.8% (13 operated patients). Pistons of Schuknecht's type were used in 23 patients with the obliterating form of otosclerosis. As to late results, in 21 of the evaluated patients compensation of the bone reserve to 0-10 dB was recorded in 28.6%. The mean auditory gains as regards speech frequencies higher than 10 dB were achieved in 47.6%. Favourable late results were thus recorded in 76.2% of operated patients with the obliterating form of otosclerosis. Deterioration of hearing occurred in this group in one operated patient (4.8%).

[Revision after surgical procedures in the middle ear and mastoid]

In a group of 46 revised operations the most frequent cause of revision was persisting secretion--in 41 patients. After elimination of general causes and after failure of conservative treatment, during revision the following local causes were revealed: relapse of cholesteatoma in 44%, inflammation of the residual or repneumatized spaces in 41%, ostitis of the long process of the incus in 10% and inflammation in the divided trepanation cavities in 5%. By the first revision the authors achieved a dry trepanation cavity in 58.5% of the operated patients. By the second and third revision they increased the number of dry trepanation cavities to 83% and in the remaining ones there was only an occasional secretion. The revision involved usually a more radical procedure. In some of the patients operated by the "closed" technique the authors changed to the "open" technique. A radical approach to the auditory ossicles and the ear drum, if they were preserved during the primary operation, led to a deterioration of hearing in 22 of 41 operated patients, i. e. in 53.66%. This is the cost of obtaining a dry trepanation cavity.