Milena Iwaszko

Clinical significance of the HLA-E and CD94/NKG2 interaction

HLA-E belongs to the non-classical HLA (class Ib family) broadly defined by a limited polymorphism and a restricted pattern of cellular expression. So far, only two functional alleles differing at only one amino acid position (non-synonymous mutation) in the α2 heavy chain domain, where an arginine in position 107 in HLA-E*0101 is replaced by a glycine in HLA-E*0103, have been reported. The interaction between non-classical HLA-E molecule and CD94/NKG2A receptor plays a crucial role in the immunological response involving natural killer (NK) cells and cytotoxic T lymphocytes. All proteins forming CD94/NKG2 receptors are encoded by genes situated in the same cluster on chromosome 12, allowing tight control over the order of their expression. The inhibitory members of the NKG2 receptor family are available on the cell surface before activating the members to prevent autoimmune incidents during immune cells’ ontogenesis. In the present review, the potential role of this interaction in viral infection, pregnancy and transplantation of allogeneic hematopoietic stem cells (HSC) is presented and discussed. The review will also include the effect of HLA-E polymorphism on the outcome of HSC transplants in humans.

[The role of HLA-E polymorphism in immunological response].

The HLA-E protein is one of the most extensively studied MHC class Ib antigens and the least polymorphic one compared to other MHC class I molecules. In the human population there have been reported just ten alleles encoding three different peptides. Only two of these alleles, namely HLA-E*0101 and HLA-E*0103, are widely distributed (around 50% each). The proteins encoded by these alleles differ from each other in one amino acid at position 107. In HLA-E*0101 it is arginine and in HLA-E*0103 it is glycine. The difference between these proteins manifests itself in surface expression levels, affinities to leader peptides and thermal stabilities of their complexes. The HLA-E molecule is a ligand for CD94/NKG2 receptors on NK cells and TCR receptors on NK-CTL (NK-cytotoxic T lymphocyte) cells, so it plays a double role in both innate and adaptive immunity. This paper reviews the knowledge on the role of the HLA-E molecule in the immunological response. Aspects related to polymorphism of the HLA-E gene and the course of several diseases including type I diabetes, ankylosing spondylitis, HCV and HIV infections, nasopharyngeal cancer and recurrent spontaneous abortions, as well as the outcome of hematopoietic stem cell transplantation, are presented and discussed in more detail.

Polymorphisms within the human leucocyte antigen‐E gene and their associations with susceptibility to rheumatoid arthritis as well as clinical outcome of anti‐tumour necrosis factor therapy

Involvement of the non‐classical human leucocyte antigen‐E (HLA‐E) in both innate and acquired immune response suggests its possible role in development of autoimmune pathologies. This study was undertaken to investigate relationships between the HLA‐E gene single nucleotide polymorphisms (SNPs) and a risk of rheumatoid arthritis (RA), as well as to evaluate a potential of these polymorphisms to modulate clinical outcome of anti‐tumour necrosis factor (TNF) treatment in female patients. A total of 223 female patients with RA receiving anti‐TNF biological therapy and 134 female healthy subjects were enrolled into the study. Genotypings for two SNPs within the HLA‐E gene (rs1264457 HLA‐E*01:01/01:03; rs1059510 HLA‐E*01:03:01/01:03:02) were performed using a polymerase chain reaction (PCR) amplification employing LightSNiP assays. Clinical response was evaluated according to the European League Against Rheumatism (EULAR) criteria at 12 and 24 weeks after initiation of the therapy. The frequency of the HLA‐E*01:01/01:01 genotype was decreased significantly in RA patients in comparison to controls (P = 0·031). The presence of the HLA‐E*01:01/01:01 genotype in patients correlated with better EULAR response after 12 weeks of anti‐TNF treatment, while 01:03 allele carriers were generally unresponsive to the treatment (P = 0·014). The HLA‐E*01:03/01:03 genotype was also over‐represented among non‐responding patients in comparison to HLA‐E*01:01/01:01 homozygotes (P = 0·021). With respect to the HLA‐E rs1059510 variation, a better response after 12 weeks was observed more frequently in patients carrying the HLA‐E*01:03:01/01:03:01 genotype than other genotypes (P = 0·009). The results derived from this study imply that HLA‐E polymorphisms may influence RA susceptibility and affect clinical outcome of anti‐TNF therapy in female RA patients.

Significance of association of HLA-C and HLA-E with psoriatic arthritis

Psoriatic arthritis (PsA) is a complex genetic disorder that results from an interplay between multiple genetic and environmental factors. The aim of the study was to assess the significance of the association between the HLA-C and HLA-E allelic groups and PsA. Our results confirm the association between HLA-C(∗)06 and PsA (OR=5.16, p<0.0001). Furthermore, HLA-C(∗)06-positive patients develop more severe disease (p<0.01) and more frequently present with polyarticular pattern of PsA (p=0.08). Additionally our study revealed that the HLA-C(∗)02 allele was more frequently observed in PsA patients (OR=5.40, p<0.0005) and also that the HLA-E(∗)01:01 allele was significantly over-represented among HLA-C(∗)02-negative patients in comparison to healthy individuals (OR=6.44, p=0.045). Therefore these results suggest that the HLA-E and HLA-C(∗)02 molecules may also play an important role in determination immune response contributing to the PsA development.

Influence of NKG2D Genetic Variants on Response to Anti-TNF Agents in Patients with Rheumatoid Arthritis

A natural killer group 2 member D (NKG2D) acts as a powerful activating and co-stimulatory receptor on immune effector cells including NK and T cells. Disruptions within the NKG2D signalling pathway may trigger an exacerbated immune response and promote autoimmune reactions. The objective of the study was to evaluate a plausible role of polymorphisms within the NKG2D gene as a predictor of how effective anti-tumor necrosis factor (TNF) therapy is in rheumatoid arthritis (RA) patients. A total of 280 RA patients receiving anti-TNF therapy were genotyped for NKG2D rs2255336 (A > G), rs1049174 (C > G), and rs1154831 (C > A). Clinical response was evaluated according to the European League against Rheumatism (EULAR) criteria at the 12th and 24th week. Both the NKG2D rs225336 and rs1049174 polymorphisms were significantly associated with efficacy of TNF inhibitors. Inefficient therapy was more frequently observed in patients with rs2255336 GG or rs1049174 CC genotype as compared to other genotypes (p-value = 0.003 and p-value = 0.004, respectively). The presence of the rs2255336 G or the rs1049174 C allele correlated with a worse EULAR response (p-value = 0.002, p-value = 0.031, respectively). Moreover, patients carrying the rs2255336 or rs1049174 heterozygous genotype achieved better EULAR responses than patients with homozygous genotypes (p-value = 0.010 and p-value = 0.002, respectively). Data from the present study provides evidence that NKG2D polymorphisms may affect response to anti-TNF inhibitors in RA patients.

Influence of CD94 and NKG2A variants on susceptibility to rheumatoid arthritis and efficacy of anti-TNF treatment

OBJECTIVES The present study aimed to investigate relationships between the CD94 and NKG2A gene polymorphisms and the risk of rheumatoid arthritis (RA) development as well as their association with the response to anti-TNF therapy. METHODS A total of 284 patients with RA receiving anti-TNF therapy and 124 healthy subjects were enrolled to the study. Genotypings for CD94 (rs2302489) and NKG2A (rs7301582, rs2734440, rs2734414) polymorphisms were performed using a polymerase chain reaction (PCR) amplification employing LightSNiP assays (TIB-MolBiol, Berlin, Germany). Clinical response was evaluated at 12th and 24th week after initiation of the therapy according to the EULAR response criteria. RESULTS The frequency of the CD94 AA genotype was significantly decreased in RA patients compared to controls (OR=0.44; P=0.016). The CD94 AA homozygotes were also more common among patients negative to anti-cyclic citrullinated peptide (anti-CCP) antibodies (OR=11.28; P=0.001) as compared to anti-CCP-positive patients and the presence of the CD94 allele A was associated with lack of anti-CCP antibodies (OR=5.00; P=0.0005). The CD94 rs2302489 TT genotype was over-represented in patients exhibiting worse EULAR response at 12th week (OR=3.33; P=0.017). Furthermore, the lack of response after 12 weeks was more frequent among patients carrying the NKG2A rs7301582C allele (OR=3.68; P=0.019) or the CC genotype (OR=3.58; P=0.035) in comparison to allele T or CT/TT genotypes, respectively. CONCLUSIONS These results indicate that CD94 and NKG2A polymorphisms may contribute to genetic susceptibility to RA or affect the response to anti-TNF therapy in patients of Caucasian origin.

Polymorphisms within the HLA‐E gene and their associations with susceptibility to rheumatoid arthritis as well as clinical outcome of anti‐TNF therapy

Involvement of the non‐classical human leucocyte antigen‐E (HLA‐E) in both innate and acquired immune response suggests its possible role in development of autoimmune pathologies. This study was undertaken to investigate relationships between the HLA‐E gene single nucleotide polymorphisms (SNPs) and a risk of rheumatoid arthritis (RA), as well as to evaluate a potential of these polymorphisms to modulate clinical outcome of anti‐tumour necrosis factor (TNF) treatment in female patients. A total of 223 female patients with RA receiving anti‐TNF biological therapy and 134 female healthy subjects were enrolled into the study. Genotypings for two SNPs within the HLA‐E gene (rs1264457 HLA‐E*01:01/01:03; rs1059510 HLA‐E*01:03:01/01:03:02) were performed using a polymerase chain reaction (PCR) amplification employing LightSNiP assays. Clinical response was evaluated according to the European League Against Rheumatism (EULAR) criteria at 12 and 24 weeks after initiation of the therapy. The frequency of the HLA‐E*01:01/01:01 genotype was decreased significantly in RA patients in comparison to controls (P = 0·031). The presence of the HLA‐E*01:01/01:01 genotype in patients correlated with better EULAR response after 12 weeks of anti‐TNF treatment, while 01:03 allele carriers were generally unresponsive to the treatment (P = 0·014). The HLA‐E*01:03/01:03 genotype was also over‐represented among non‐responding patients in comparison to HLA‐E*01:01/01:01 homozygotes (P = 0·021). With respect to the HLA‐E rs1059510 variation, a better response after 12 weeks was observed more frequently in patients carrying the HLA‐E*01:03:01/01:03:01 genotype than other genotypes (P = 0·009). The results derived from this study imply that HLA‐E polymorphisms may influence RA susceptibility and affect clinical outcome of anti‐TNF therapy in female RA patients.

OP0071 Tnf-Alpha, TNF Receptor, HLA-E and NKG2A Gene Polymorphisms and Response to Anti-TNF-Alpha Treatement in Rheumatoid Arthritis

Background Despite the fact that therapy with TNF-alpha inhibitors constitutes a breakthrough in rheumatoid arthritis (RA) management, no improvement is still achieved in approximately 30% of cases. Objectives The aim of the study was to evaluate whether single nucleotide polymorphisms (SNPs) within the TNF-α and TNF receptor, and HLA-E and NKG2A receptor encoding genes affect the efficacy of therapy with TNF-α inhibitors in patients with RA. Methods For these purpose 280 RA patients who had been treated with TNF-alpha inhibitors for at least 6 months or they stopped therapy because of adverse events were investigated and genotyped for 9 SNPs within the TNFA promoter (rs1800629 G>A; rs361525 G>A; rs1799724 C>T); TNF receptors (TNFR1A: rs767455 G>A; TNFR1B: rs1061622; T>G) while 89 patients were studied for the HLA-E (rs1264457 C>T; HLA-E*01:01, HLA-E*01:03, A>G) and NKG2A (rs7301582 C>T; rs2734440 A>G) genes using LightSNiP typing or Custom TaqMan® SNP Genotyping Assays. Results Among polymorphisms located within TNF-alpha and receptors genes only the TNFR1A (rs767455, G>A) and one of the TNFA (rs1799724, C>T) promoter polymorphisms were found to be associated with response to anti-TNF therapy. Significantly more patients with the homozygous TNFR1A AA genotype achieved a good EULAR response at 3 months compared to patients carrying the G allele (p=0.011). At week 24 DAS28 was significantly lower in patients homozygous for the TNFA T variant (DAS28 – 2.05) compared to the C allele carriers (p=0.045). As for HLA-E and NKG2A genes, after 3 months of anti-TNF treatment the significantly worse (EULAR DAS28) response was observed in patients carrying the HLA-E C allele (20/45 vs. 9/28, p=0.030), HLA-E*01:03/01:03 genotype (8/10 vs. 30/73, p=0.038), NKG2A-(rs7301582)-CC genotype (28/51 vs. 10/33, p=0.043) or NKG2A-(rs2734440)-AA genotype (15/26 vs. 15/50, p=0.026). At week 12 low disease activity or remission was not observed in any of the patients with the HLA-E CC genotype (p=0.09). Also treatment failure (inefficiency or loss of effectiveness of therapy) was more frequently observed in the HLA-E CC homozygous patients (5/8 vs. 12/61, p=0.018) as well as in those with the NKG2A-(rs2734440)-AA genotype (15/37 vs. 3/33, p=0.005). Conclusions These results imply that the polymorphisms within genes coding for TNF-alpha and its TNFR1 receptor as well as HLA-E and NKG2A affect the response to anti-TNF therapy in patients with RA. Acknowledgements Supported by the UMO-2012/05/N/NZ5/02607 and 2011/01/B/NZ5/05367 grants from the National Science Center. Disclosure of Interest J. Swierkot Grant/research support: UMO-2012/05/N/NZ5/02607 and 2011/01/B/NZ5/05367, M. Iwaszko Grant/research support: UMO-2012/05/N/NZ5/02607 and 2011/01/B/NZ5/05367, K. Gebura Grant/research support: UMO-2012/05/N/NZ5/02607 and 2011/01/B/NZ5/05367, B. Nowak Grant/research support: UMO-2012/05/N/NZ5/02607 and 2011/01/B/NZ5/05367, L. Korman Grant/research support: UMO-2012/05/N/NZ5/02607 and 2011/01/B/NZ5/05367, K. Kolossa: None declared, S. Jeka: None declared, P. Wiland: None declared, K. Bogunia-Kubik Grant/research support: UMO-2012/05/N/NZ5/02607 and 2011/01/B/NZ5/05367 DOI 10.1136/annrheumdis-2014-eular.5416

IL-6 gene polymorphism is associated with protein serum level and disease activity in Polish patients with rheumatoid arthritis

Interleukin 6 (IL‐6) is a pro‐inflammatory cytokine involved in the development of rheumatoid arthritis (RA). The present study aimed to determine the possible association of the IL6 (rs1800795, G > C) polymorphism with RA susceptibility, disease progression and protein serum levels. Distribution of IL6 alleles and genotypes was similar in RA patients and controls. As expected, patients before induction of anti‐tumour necrosis factor agents had significantly higher IL‐6 levels as compared with controls (P = 0.002). The CC homozygous patients were characterised with the highest average concentrations of this pro‐inflammatory cytokine before treatment (P = 0.028), and they also more frequently presented with more active disease (P = 0.048). These results imply that the IL6 rs1800795 CC homozygosity may play a rather unfavourable role in RA.