Katarzyna Bogunia-Kubik

Killer immunoglobulin‐like receptors (KIRs) are central regulators of natural killer (NK) and T‐cell function through interactions with HLA Class I ligands. Although KIR genes are highly polymorphic, their allele‐level diversity and their potential role in healthy ageing remain incompletely characterized. In this study, we performed high‐resolution, allele‐level genotyping of 10 KIR genes in three ethnically distinct populations from Bulgaria, Romania, and Turkey. Each population was analysed separately, using unrelated healthy young individuals (≤ 35 years) and ethnically matched healthy elderly individuals (> 65 years); allele frequencies and two‐locus KIR haplotypes were then compared between age groups. Across all populations, most KIR alleles showed similar distributions between young and elderly cohorts, consistent with a shared European allelic framework. In the Bulgarian cohort, only KIR3DL2*01001 showed a trend towards increased frequency among the elderly. In the Romanian cohort, healthy elderly individuals exhibited significant enrichment for KIR2DL2*00101 and KIR2DL3*00201 , along with increased retention of the inhibitory receptors KIR2DL1, KIR2DL2, and KIR2DL3. In the Turkish cohort, several low‐frequency alleles of the framework genes KIR3DL2 and KIR3DL3 showed age‐associated trends but did not remain significant after multiple‐testing correction. Haplotype analysis revealed that the Bulgarian allele‐level association was largely captured within the KIR3DL1*00501 ~ KIR3DL2*01001 haplotype, while multiple Romanian haplotypes carrying KIR2DL2*00101 were enriched in the elderly group. Independent analyses involving Poles also showed a largely shared allelic repertoire characteristic of all four European populations. These findings provide an exploratory assessment of KIR allele‐level variation in healthy ageing and suggest that the preservation of specific inhibitory KIR configurations may represent an immunogenetic feature of healthy ageing in Southeastern European populations. However, these associations should be considered preliminary and require validation in larger cohorts before definitive conclusions can be made.

Background: Telomere length and telomerase activity are important determinants of haematopoietic cell proliferative capacity and may influence outcomes after allogeneic haematopoietic stem cell transplantation (allo-HSCT). Genetic variation within the telomerase reverse transcriptase (TERT) gene may further contribute to transplantation success and post-transplant complications. Methods: Telomere length was assessed in 98 paediatric allo-HSCT recipients and their donors using quantitative real-time PCR before allo-HSCT and at one and two years post-transplantation. Selected four TERT polymorphisms (rs2736100, rs2853669, rs2735940, and rs10069690) were genotyped in donors and recipients before allo-HSCT. Associations between telomere length, genetic variants, and clinical outcomes were analysed. Results: Telomere length did not differ between recipients and donors before transplantation; however, donors younger than 18 years exhibited significantly longer telomeres. Telomere length increased at one and two years after allo-HSCT compared with pre-transplant values, with the most pronounced changes observed in patients with acute lymphoblastic leukaemia. No direct associations were found between TERT polymorphisms and telomere length. Nevertheless, the recipient rs2735940 T allele was associated with improved survival, the donor rs2736100 G allele with the achievement of complete chimerism, and the recipient rs2853669 C allele with an increased risk of acute graft-versus-host disease (aGvHD). Haplotype analysis identified associations between TERT variants and cytomegalovirus reactivation as well as aGvHD. Conclusions: Paediatric allo-HSCT is associated with dynamic post-transplant changes in telomere length. Although TERT polymorphisms did not directly affect telomere length, several variants were linked with clinically relevant transplantation outcomes, highlighting the potential role of telomere biology in haematopoietic reconstitution and transplant-related complications.

Rheumatoid arthritis (RA) is a chronic autoimmune disease characterized by persistent synovial inflammation and progressive joint destruction. While conventional αβ T cells have been extensively studied, the contribution of γδ T cells to RA pathogenesis remains insufficiently understood. Unlike αβ T cells, γδ T cells recognize antigens independently of major histocompatibility complex (MHC) restriction, and their surface receptor expression plays a pivotal role in regulating effector functions. This study aimed to investigate the phenotype and surface receptor profile of γδ T cells in RA patients undergoing anti-TNF therapy, to better understand their potential immunoregulatory and prognostic significance. Peripheral blood samples were collected from RA patients before and during treatment with TNF inhibitors, as well as from healthy controls. Flow cytometry was used to quantify γδ T cell frequency and to assess the expression of selected activation, differentiation, and exhaustion markers on their surface. RA patients exhibited a significant reduction in the frequency of circulating γδ T cells compared with healthy controls. Moreover, γδ T cells in RA displayed phenotypic features of advanced differentiation and functional exhaustion, including altered expression of key surface receptors. The observed alterations in γδ T cell phenotype and receptor expression suggest chronic immune activation in RA. These findings highlight the potential of γδ T cell surface markers as candidate biomarkers for disease activity and response to anti-TNF therapy.

Background: The emergence of the COVID-19 pandemic has accelerated research into diverse immune response mechanisms. One key area of interest is the regulation of cytotoxic activity by Natural Killer (NK) cells. These cells rely on a dynamic interplay between activating and inhibitory surface receptors that recognize specific ligands on target cells. Among these, receptors from the NKG2 family are particularly important, as maintaining their proper balance and function is essential for controlling NK cell cytotoxicity. Methods: In this study we employed qPCR to assess the genetic variability using single-nucleotide polymorphisms (SNPs) of NKG2A and NKG2D receptors and their ligands HLA-E and MICA/MICB. NKG2C deletion was determined by PCR-SSP, and serum-soluble levels of HLA-E and MICA/MICB molecules were measured by ELISA and Luminex methods. Results: Genotyping studies revealed that both NKG2A rs7301582 T and HLA-E rs1264457 A (HLA-E*01:01) alleles were predominant among infected individuals (OR = 2.21, p = 0.0258 and OR = 2.84, p = 0.0257, respectively). In contrast to MICB rs1065075 A, the MICA rs1051792 A (129Met) allele was most commonly found in hospitalized patients (OR = 14.95, p = 0.0114). The presence of the NKG2C del variant tended to be associated with an increased risk of SARS-CoV-2 infection (OR = 2.02, p = 0.0694). Moreover, higher concentrations of serum-soluble MICB was detected in infected individuals as compared to the control group (p = 0.008). Conclusions: Genetic variability of NK cell receptors and ligands as well as serum levels of their soluble forms showed associations with the risk of development of COVID-19 and the severity of its symptoms.

Multiple myeloma is a neoplastic disease characterised by the proliferation of clonal, atypical plasma cells. In cancer cells, the balance between two paths of cell death, necroptosis and apoptosis, is disrupted. The aim of this study was to analyse the occurrence of polymorphisms in genes encoding key proteins for the necroptosis process, i.e., RIPK-1, RIPK-3 and MAPKAPK2. We investigated the potential relations between the occurrence of genetic variability and the clinical course of the disease. We analysed six single-nucleotide polymorphisms in a population of patients with multiple myeloma (n = 205) and healthy volunteers (n = 100): RIPK1 rs2272990, RIPK1 rs9391981, RIPK3 rs724165, RIPK3rs3212243, MAPKAPK2, rs45514798 and MAPKAPK2 rs4073250. We found that genotypes rs9391981 CG, rs724165 CG, rs3212243 GG, and rs4073250 AA were independent predictors of overall survival, while genotype MAPKAPK2 rs4073250 AA was an independent predictor of progression-free survival. MAPKAPK2 rs45514798 AA was associated with polyneuropathy after thalidomide therapy. In conclusion, some of the SNPs tested have potential prognostic value and could be used as marker of survival in patients with multiple myeloma.

Introduction Telomerase reverse transcriptase (TERT) is a catalytic subunit of telomerase that maintains genome stability by maintaining telomere length (TL). The massive proliferation of donor cells in the recipient’s body for engraftment results in accelerated telomere shortening. Genetic variability within the TERT gene affects telomerase activity, and was shown to influence of haematopoietic stem cell transplantation (HSCT) outcome. In the present study, we aimed to analyse the effect of recipient and donor TL and TERT single nucleotide polymorphism (SNP) on the occurrence of post-HSCT complications. Methods Our study included 120 recipient-donor pairs. TERT promoter (TERTp) SNP (rs2853669) SNP variant was detected with the use of the LightSNiP typing assay employing real-time polymerase chain reaction (PCR) amplifications. Telomere length measurements were performed using qPCR test kits (ScienCell’s Absolute Human Telomere Length Quantification qPCR Assay Kit [AHTLQ], Carlsbad, CA, USA). Results The presence of TERTp rs2853669 T allele in the recipient was associated with a higher risk for acute graft-versus-host-disease (aGvHD) manifestation (p = 0.046) and a significantly shorter aGvHD-free survival (p = 0.041). The latter association was further confirmed in a Cox proportional hazards model (p = 0.043). However, no statistically significant association between telomere length and post-transplant complications was observed. Furthermore, we found that shorter TL characterized donors of patients with late complete chimerism at 180 day after HSCT (p = 0.011). Conclusion Our results suggest that recipient allele TERTp rs2853669 T is a marker of unfavourable outcome in the context of aGvHD. Shorter TL in donors could be associated with later achievement of complete chimerism.

This Research Topic focuses on recent advances in the identification of diagnostic, prognostic and predictive biomarkers for inflammatory rheumatic diseases (IRDs), as well as recent advances in cellbased therapies used in their treatment (1). The second volume is composed of 3 review articles and 7 original articles, and the manuscripts collected are especially dedicated to biomarkers in IRDs. They present the effects of various approaches leading to the identification and description of biomarkers, such as: (i) a review of existing biomarker recommendations and meta-analysis of existing data (e.g. of epigenetic and DNA methylation studies); (ii) application of more laboratory-based analyses, such as measurement of single protein concentrations, circulating exosomal miRNA and serum proteome profiling, detection of specific antibodies in serum and saliva; and (iii) implementation of newer biostatistical methods including machine learning. Consequently, in addition to well-known associations, several new findings in the field of IRD biomarkers are provided. Dong Liu et al. reviewed and formulated guidelines for biomarkers in the diagnosis and assessment of patients with axial spondyloarthritis (axSpA). They highlighted the usefulness of currently applied HLA-B27 testing in patients with suspected axSpA and regular C-reactive protein/erythrocyte sedimentation rate monitoring as specifically recommended for axSpA evaluation (2).Arduino A Mangoni and Angelo Zinellu in their systematic review and meta-analysis focused on the pathophysiological role of neopterin known as a biomarker of inflammation and oxidative stress, suggesting that it may be useful in identifying rheumatic diseases. Neopterin is an organic compound belonging to the pteridine class of heterocyclic compounds and belongs to the chemical group known as pteridines. It is synthesized by human macrophages after interferon-gamma stimulation and serves as a marker of activation of the cellular immune system.The role of epigenetic regulation of gene expression and function of DNA methylation was discussed by Yanqing Wang et al. who argue that genome methylation analysis may be a beneficial tool to aid in the early diagnosis of Sjögren's syndrome (SjS). Interestingly, in addition to the human leukocyte antigen (HLA) locus, several regions were found to be differentially methylated in SjS patients, including genes regulated by type I interferon, the runt-related transcription factor gene (RUNX1), lymphotoxin-α (LTA) and myxovirus A resistance protein (MxA).More experimental analyses, such the application of molecular profiling and gene expression studies for biomarker detection was also proposed. Maria Maddalena Angioni et al. performed a transcriptomic analysis of whole blood and a comparison of molecular profiles between psoriatic arthritis (PsA) patients in clinical remission after TNF inhibitor (TNFi) treatment, PsA patients with active disease and healthy controls. The results pointed the role of dysregulation of two genes involved in the processes of inflammation perpetuation and bone metabolism. Downregulation and upregulation of FOS and CCDC50, respectively, were identified as contributing to the pathophysiology of PsA as described in a study on clinical remission in PsA patients treated with TNFi.Serum proteome profiling was used in another study by Laura Cuesta-López et al. investigating ageand sex-matched control patients with newly diagnosed rheumatoid arthritis (RA) patients, and patients with established RA (with a disease duration of more than 25 years). An additional longitudinal study was conducted on two cohorts of RA patients treated with methotrexate or tofacitinib for 6 months. By analysing their cardiovascular and cardiometabolic proteome (examining serum profiling of 184 proteins using the Olink technology platform), the authors were able to identify changes in serum proteins associated with cardiovascular disease in RA patients and identify candidate protein biomarkers to distinguish RA patients from healthy individuals (such as elevated levels of CTSL1, SORT1, SAA4, TNFRSF10A, ST6GAL1 and CCL18). They were also able to show how methotrexate and tofacitinib affect serum levels of these proteins, and to identify SAA4 as a potential biomarker of response to these therapies.Serum and salivary antibody levels against Porphyromonas gingivalis (P. gingivalis, a major periodontal pathogen) were investigated by Anna Svärd et al. in a Swedish RA patient cohort. The results indicated the local production of IgA directed against P. gingivalis-specific Arg-specific gingipain B (anti-RgpB) in the salivary glands, which is not accompanied by systemic antibody production. Higher levels of IgA anti-RgpB antibodies in saliva were detected in RA patients compared to healthy controls. However, despite some common features and a potential link between RA and periodontitis (e.g., elevated levels of anti-citrullinated peptide antibodies [ACPAs])(3), anti-RgpB antibodies were not found to be associated with RA disease activity, periodontitis or serum IgG ACPAs.Four remaining original articles addressed biomarkers related to lupus nephritis (LN) development, the disease onset, activity, and response to treatment.The study by Liubing Li et al. aimed to assess whether serum levels of human epididymis protein 4 (HE4) can identify pathological classes of LN in adults and children with systemic lupus erythematosus (SLE). The study was conducted on three cohorts of SLE patients (those without LN as well as LN patients with adult or childhood onset) and showed an association of higher serum HE4 levels with adult onset LN. It was also observed that among patients with adult onset LN, elevated HE4 levels were more common in patients with proliferative LN and in patients with chronic class IV lesions.It was also found that urinary L-selectin (uL-selectin) level may act as a novel biomarker of disease activity and renal...

Multiple myeloma (MM) is a hematological malignancy characterized by the presence of abnormal plasma cells. It is associated with anemia, bone lesions and renal dysfunction. Immunomodulatory drugs (IMiDs) are commonly used in MM treatment. Recent studies indicate that their therapeutic effect is caused by binding to cereblon (CRBN), which in turn causes the degradation of 2 important immune cell regulatory factors, IKZF1 and IKZF3. These are necessary for the anti-myeloma effect of IMiDs. Their expression level has been shown to affect MM survival and response to treatment. Potentially important single-nucleotide polymorphisms (SNPs) in the genes coding for IKZF1 and IKZF3 have been identified, but they have not been analyzed in MM patients before. The study was designed to establish the relationship between 4 SNPs in the genes coding for IKZF1 (rs61731359, rs4132601 and rs10272724) and IKZF3 (rs907091), and MM survival, response to treatment and other parameters. The study involved 222 MM patients, as well as 100 control individuals. The IKZF1 and IKZF3 genotypes were determined by the LightSNiP assay. Genotyping was performed in the real-time polymerase chain reaction (PCR) LightCycler 480 device. No difference was observed between the patients and the controls for any of the SNPs, but the IKZF1 and IKZF3 variants were associated with various clinical parameters. Allele IKZF1 rs4132601 G was more common in the patients with worse response to first-line therapy (p = 0.040), particularly in the patients treated with thalidomide (p = 0.017). The patients tended to have worse overall survival. IKZF3 rs907091 CC was detected more commonly in the patients in stage I than in those in stages II and III, according to the International Staging System (ISS) criteria (p = 0.015). This genotype was also associated with a higher albumin level (p = 0.033), and was less common in the patients with the albumin level below 3.5 g/dL (p = 0.030). Our results suggest that IKZF1 rs4132601 and IKZF3 rs907091 may affect response to treatment and progression in patients with MM.