The central role of natural killer cells in mediating acute myocarditis after mRNA COVID-19 vaccination.

BACKGROUND: Vaccine-related acute myocarditis is recognized as a rare and specific vaccine complication following mRNA-based COVID-19 vaccinations. The precise mechanisms remain unclear. We hypothesized that natural killer (NK) cells play a central role in its pathogenesis. METHODS: Samples from 60 adolescents with vaccine-related myocarditis were analyzed, including pro-inflammatory cytokines, cardiac troponin T, genotyping, and immunophenotyping of the corresponding activation subsets of NK cells, monocytes, and T cells. Results were compared with samples from 10 vaccinated individuals without myocarditis and 10 healthy controls. FINDINGS: Phenotypically, high levels of serum cytokines pivotal for NK cells, including interleukin-1ß (IL-1ß), interferon α2 (IFN-α2), IL-12, and IFN-γ, were observed in post-vaccination patients with myocarditis, who also had high percentage of CD57+ NK cells in blood, which in turn correlated positively with elevated levels of cardiac troponin T. Abundance of the CD57+ NK subset was particularly prominent in males and in those after the second dose of vaccination. Genotypically, killer cell immunoglobulin-like receptor (KIR) KIR2DL5B(-)/KIR2DS3(+)/KIR2DS5(-)/KIR2DS4del(+) was a risk haplotype, in addition to single-nucleotide polymorphisms related to the NK cell-specific expression quantitative trait loci DNAM-1 and FuT11, which also correlated with cardiac troponin T levels in post-vaccination patients with myocarditis. CONCLUSION: Collectively, these data suggest that NK cell activation by mRNA COVID-19 vaccine contributed to the pathogenesis of acute myocarditis in genetically and epidemiologically vulnerable subjects. FUNDING: This work was funded by the Hong Kong Collaborative Research Fund (CRF) 2020/21 and the CRF Coronavirus and Novel Infectious Diseases Research Exercises (reference no. C7149-20G).

Efficient and accurate KIR and HLA genotyping with massively parallel sequencing data.

Killer cell immunoglobulin like receptor (KIR) genes and human leukocyte antigen (HLA) genes play important roles in innate and adaptive immunity. They are highly polymorphic and cannot be genotyped with standard variant calling pipelines. Compared with HLA genes, many KIR genes are similar to each other in sequences and may be absent in the chromosomes. Therefore, although many tools have been developed to genotype HLA genes using common sequencing data, none of them work for KIR genes. Even specialized KIR genotypers could not resolve all the KIR genes. Here we describe T1K, a novel computational method for the efficient and accurate inference of KIR or HLA alleles from RNA-seq, whole-genome sequencing, or whole-exome sequencing data. T1K jointly considers alleles across all genotyped genes, so it can reliably identify present genes and distinguish homologous genes, including the challenging KIR2DL5A/KIR2DL5B genes. This model also benefits HLA genotyping, where T1K achieves high accuracy in benchmarks. Moreover, T1K can call novel single-nucleotide variants and process single-cell data. Applying T1K to tumor single-cell RNA-seq data, we found that KIR2DL4 expression was enriched in tumor-specific CD8+ T cells. T1K may open the opportunity for HLA and KIR genotyping across various sequencing applications.

Association of KIR2DL5, KIR2DS5, and KIR2DS1 allelic variation and atopic dermatitis.

Natural killer cells (NK) have been associated with the pathophysiology of atopic dermatitis (AD). NK function is regulated by killer cell Ig-like receptor family (KIR) receptors that interact with HLA ligands. The study goal was to focus on allelic variation in genes KIR2DL5, KIR2DS5, and KIR2DS1 with respect to AD. This was a case-control study of individuals with (n = 313) and without (n = 176) AD. Associations were estimated using logistic regression. The prevalence of KIR2DL5 was 52.5% (95% CI 48.0,57.0), KIR2DS5 was 33.0% (28.8,37.3), and KIR2DS1 was 33.6% (29.4,38.0). The presence of the KIR2DL5*001:01 increased the odds of having AD by about 86% (odds ratio (OR): 1.86(1.23,2.82) p = 0.003). The risk for individuals homozygous for KIR2DL5*001:01 was even greater (OR: 2.16 (95% CI 1.31,3.53) p = 0.0023). The odds of having AD with KIR2DL5*001:01 was similar in Whites and Blacks. Allelic variation in KIR2DS5 and KIR2DS1 was not associated with AD. There is no known HLA binding ligand for KIR2DL5. The effect of KIR2DL5*001:01 increased in the presence of HLA-B*-21TT leader sequence (2.46(1.37,4.41) p = 0.0025) and the HLA-C2 ligand (2.07 (1.37,4.41, p = 0.000002). Our study shows an independent association of the KIR2DL5*001:01 with AD and is the first study to associate AD with KIR allelic variation.

Killer cell immunoglobulin-like receptor (KIR) gene contents: Are they associated with cervical cancer?

Killer cell immunoglobulin-like receptors (KIRs) are required for natural killer cell function against virus-infected cells or tumor cells. KIR gene content polymorphisms in Indian women with cervical cancer (CaCx) remain unexplored. Hence, we analyzed the frequencies of KIR genes, KIR haplotypes, and Bx subsets to draw their association with CaCx. The polymerase chain reaction-sequence-specific primer method was used for KIR genotyping in three groups of women: healthy controls (n = 114), women with human papillomavirus (HPV) infection (n = 70), and women with CaCx (n = 120). The results showed that the frequency of KIR2DS5 was significantly higher in women with CaCx compared to women with HPV infection (p = 0.02) and healthy controls (p = 0.01). Whereas the frequency of KIR2DL5B was significantly higher in healthy controls than in women with HPV infection (p = 0.02). The total number of activating KIR genes was higher in women with CaCx than in healthy controls (p = 0.006), indicating their positive association with CaCx. Moreover, the C4T4 subset was higher in women with CaCx than in women with HPV infection, though not significant. In conclusion, our findings highlight KIR2DS5, the C4T4 subset, and activating KIR genes are susceptible factors or positively associated with CaCx. Besides KIR2DL5B, this study also reported for the first time significantly high frequency of KIR2DL1 in healthy controls, indicating its possible protective association against CaCx. Further, significantly high frequency of KIR2DL3 observed in HPV-infected women might be also a promising biomarker for viral infections. Thus, the study confirms the association of KIR genes with cervical cancer in women with HPV infection.

KIR2DL5B and HLA DRB1*12 alleles seems to be associated with protection against HIV-1 in serodiscordant couples in Burkina Faso.

The human immunodeficiency virus (HIV) belongs to the Retroviridae family and remains a public health problem in sub-Saharan Africa. Recent reports from WHO have shown that 33 million people died from HIV infections. HIV is one of the most serious fatal human diseases of the 20th and 21st centuries. However, variations in genetic and immunological factors are associated with protection against HIV infection in uninfected people exposed to HIV. This is the case with naturals killers which play an important role in the progression or regression of HIV infection. The objective of this study is to characterize certain HLA (human leukocyte antigen) class II genes and KIR genes in HIV-1 serodiscordant couples in Burkina Faso. This study was carried out at Burkina Faso among nineteen (19) HIV-1 serodiscordant couples. Classical multiplex PCR (SSP-PCR) was used to characterize the presence or absence of the KIR genes and certain class II HLAs (DRB1*11 and DRB1*12). The characterization of the KIR and HLA genes DRB1*11, DRB1*12 in this study demonstrated that the inhibitor KIR2DL5B, would confer protection against HIV-1 infection in seronegative partners (odd ratio [OR] = 0.13 [0.02-0.72] and p = 0.029), and the HLA DRB1*12 allele was associated with protection against HIV-1 infection in seronegative partners (OR = 0.16 [0.03-0.77] and p = 0.038). AA and Bx haplotypes were not found to be associated with HIV-1 infection in serodiscordant couples. This study confirms the involvement of the KIR genes in viral pathologies such as HIV-1 infection. Future larger-scale studies may provide a better understanding of the molecular mechanism by which the KIR haplotype and combination of KIR/HLA are associated with protection against HIV infection.

KIR/HLA ligands immunogenetics markers associated with outcome of hepatitis B virus infection in the Bulgarian population.

BACKGROUND: Hepatitis B virus (HBV) infection is one of the most common infections worldwide, having negative impact on world health due to the tendency for chronification with late complications such as liver cirrhosis and hepatocellular carcinoma. Natural killer (NK) cells as part of innate antiviral defense influence the clinical course of HBV infection: elimination of the virus or chronic disease. AIM: Therefore, we investigated the polymorphisms of the main gene systems, regulating NK-cell function: killer cell immunoglobulin-like receptors (KIRs) and their appropriate HLA class I ligands in 144 HBV infected patients (124 chronic carriers and 20 spontaneously recoved) and 126 ethnically matched healthy controls from the Bulgarian population in a case-control study. METHODS: KIRs and HLA ligands were determined by PCR-SSP or PCR high-resolution typing methods. RESULTS: KIR2DL5B allele variant was significantly less frequent in spontaneously recovered (SR) patients compared to healthy controls (10.0% vs. 45.5%, Pcorr=0.006). The presence of KIR3DL1*004 allele was higher in chronic HBV carriers (CH) than in controls (33.1% vs. 17.6%, Pcorr=0.036). Additionally, SR patients differed from healthy individuals by the lower frequency of HLA-Bw4Ile80 group ligands (30.0% vs 63.7%, P=0.015). Three KIR genotypes were found more frequent in healthy in comparison with HBV infected individuals: ID2 (13.5% vs 5.6%, P=0.025), KIR genotype containing 6 activating KIRs (18.0% vs 7.6%, P=0.017), and KIR genotype composed of 4 activating and 5 inhibitory KIRs (23.8% vs 5.6%, P=0.001). CONCLUSION: These data suggest that inherited KIR and HLA class I ligand polymorphisms may influence the clinical course of HBV infection.

KIR and HLA-C genes in male infertility.

PURPOSE: Approximately 50% of men reporting to clinics for assisted reproduction have abnormal sperm parameters; we therefore considered whether they differ from fertile males in terms of the frequency of KIR and HLA-C genes, suggesting the involvement of NK cells and some T cells in the inflammatory reaction that can occur in the testes, vas deferens, or epididymis. METHOD: We tested a total of 1064 men: 445 of them were patients who, together with their female partners, participated in in vitro fertilization (IVF), 298 men whose female partners suffered from recurrent spontaneous abortion. Three hundred twenty-one fertile men constituted the control group. KIRs were genotyped using KIR Ready Gene kits and HLA-C by PCR-SSP methods. RESULTS: We found differences in KIR gene frequencies between men who became fathers via natural conception and men who participated in in vitro fertilization for KIR2DL2 (p/pcorr. = 0.0015/0.035, OR = 1.61), KIR2DL5 gr.2 (p/pcorr. = 0.0023/0.05, OR = 1.64), KIR2DS2 (p/pcorr. = 0.0019/0.044, OR = 1.59), and KIR2DS3 (p/pcorr. = 0.0016/0.037, OR = 1.67). KIRs in Cen AA region were significantly overrepresented in fertile males than in IVF males (p/pcorr. = 0.0076/0.03, OR = 0.67), whereas Cen AB + Cen BB frequency was higher in IVF males than in fertile males (p/pcorr. = 0.0076/0.03, OR = 1.50). We also observed a limited association in KIR-HLA-C combinations. CONCLUSION: Fertile men differ in profile of KIR genes and KIR-HLA-C combinations from men participating in IVF.

A Platform for Extracellular Interactome Discovery Identifies Novel Functional Binding Partners for the Immune Receptors B7-H3/CD276 and PVR/CD155.

Receptors expressed on the plasma membrane and their interacting partners critically regulate cellular communication during homeostasis and disease, and as such represent main therapeutic targets. Despite its importance for drug development, receptor-ligand proteomics has remained a daunting field, in part because of the challenges associated to the study of membrane-expressed proteins. Here, to enable sensitive detection of receptor-ligand interactions in high throughput, we implement a new platform, the Conditioned Media AlphaScreen, for interrogation of a library consisting of most single transmembrane human proteins. Using this method to study key immune receptors, we identify and further validate the interleukin receptor IL20RA as the first binding partner for the checkpoint inhibitor B7-H3. Further, KIR2DL5, a natural killer cell protein that had remained orphan, is uncovered as a functional binding partner for the poliovirus receptor (PVR). This interaction is characterized using orthogonal assays, which demonstrate that PVR specifically engages KIR2DL5 on natural killer cells leading to inhibition of cytotoxicity. Altogether, these results reveal unappreciated links between protein families that may importantly influence receptor-driven functions during disease. Applicable to any target of interest, this technology represents a versatile and powerful approach for elucidation of receptor-ligand interactomes, which is essential to understand basic aspects of the biology of the plasma membrane proteins and ultimately inform the development of novel therapeutic strategies.

Killer immunoglobulin-like receptor genotypes and chronic myeloid leukemia outcomes after imatinib cessation for treatment-free remission.

BACKGROUND: Natural Killer (NK) cells are innate lymphoid cells that can be cytotoxic toward a large panel of solid tumors and hematological malignancies including chronic myeloid leukemia (CML). Such a cytotoxicity depends on various receptors. Killer immunoglobulin-like receptors (KIR) belong to these receptors and are involved in maturation process, then in the activation abilities of NK cells. METHODS: We investigated the prognostic impact of the KIR2DL5B genotype in 240 CML patients included in two clinical trials investigating tyrosine kinase inhibitors (TKI) discontinuation: STIM and STIM2. RESULTS: After adjustment for standard risk factors in CML, we found that the inhibitory receptor KIR2DL5B-positive genotype was independently related to a delayed second deep molecular remission (HR 0.54, 95% CI [0.32-0.91], P = 0.02) after TKI rechallenge but not to time to first deep molecular remission or treatment-free remission rates. CONCLUSION: These results suggest that KIR2DL5B could carry a role in lymphocyte-mediated control of leukemic residual disease control in patient with CML relapse.

KIR2DS1, 2DS5, 3DS1 and KIR2DL5 are associated with the risk of head and neck squamous cell carcinoma in Iranians.

BACKGROUND: Activating and inhibitory KIR receptors (aKIR, iKIR) control the development and function of NK cells whose function alterations adjust the tumor microenvironment immunity. This research was conducted to determine the KIRs gene impact on genetic predisposition to Head and Neck Squamous Cell Carcinoma (HNSCC) in Iranians. METHODS: KIR genotyping using sequence-specific primers-polymerase chain reaction (SSP-PCR) method was performed to identify the presence of all 16 KIR genes in 285 HNSCC patients, including laryngeal, oral cavity and pharyngeal SCC and 273 controls (CNs). RESULTS: Comparison of KIRs gene frequency between HNSCC and CNs revealed a highly significant increase in KIR2DL5, 2DS1, 2DS5, 3DS1 and CxT4 genotype and a decrease in KIR2DS4 deleted variant and AA genotype carriers. A significant increase was noted in individuals withhigher iKIRs than aKIRs in HNSCC compared with CNs. Individuals with ≥4 iKIR and those with ≥5 aKIRs were significantly more common in HNSCC than CNs. 68distinct KIR genotypes were identified in 558 individuals. CONCLUSION: Our findings determined the detrimental impact of KIR2DS1, 2DS5, 3DS1, 2DL5 and CxT4 genotype as well as the protective impact of KIR2DS4del and AA genotype on genetic predisposition to HNSCC in Iranians.

The effect of killer cell immunoglobulin-like receptor genotype on outcome of hematopoietic stem cell transplantation from matched sibling.

The alloreactivity of natural killer (NK) cell after allogeneic hematopoietic stem cell transplantation (AHSCT) is regulated by the interaction between donor killer immunoglobulin-like receptors (KIRs) and recipient human leukocyte antigen (HLA)-class I molecules. The aim was to identify KIR genes, haplotypes and their HLA-class I ligands and to investigate their association with transplantation outcome. The study included 65 patient/donor pairs who received AHSCT from HLA-matched identical siblings. KIR genotyping was done for donors using reverse sequence specific oligonucleotide probes (rSSO) coupled with luminex technology, while HLA-C genotyping was performed in patients using rSSO strip assay. In multivariate analysis, KIR2DS4 was associated with significant reduced incidence of relapse (p = .002). A trend towards reduced incidence of relapse was also observed with more than two KIR B motifs (p = .09), whereas a significant increased relapse was associated with homozygous HLA-C2 ligand compared to combined C1/C2 and C1/C1 (p = .04). Activating KIR2DS3 was associated with rapid leukocyte engraftment (p = .02). While, KIR 2DL5 was associated with decreased CMV infection (p = .03) and better platelets engraftment (p = .05). KIR genes, haplotypes and HLA-C alleles have an impact on HSCT outcome. Better selection of donors with favorable KIR genotype can improve HLA-matched sibling HSCT outcome especially for AML patients.

HIV exposed seronegative (HESN) compared to HIV infected individuals have higher frequencies of telomeric Killer Immunoglobulin-like Receptor (KIR) B motifs; Contribution of KIR B motif encoded genes to NK cell responsiveness.

Previously, we showed that Killer Immunoglobulin-like Receptor (KIR)3DS1 homozygotes (hmz) are more frequent in HIV exposed seronegative (HESN) than in recently HIV infected (HIV+) individuals. KIR3DS1 encodes an activating Natural Killer (NK) cell receptor (NKR). The link between KIR genotype and HIV outcomes likely arises from the function that NK cells acquire through expression of particular NKRs. An initial screen of 97 HESN and 123 HIV+ subjects for the frequency of KIR region gene carriage observed between-group differences for several telomeric KIR region loci. In a larger set of up to 106 HESN and 439 HIV+ individuals, more HESN than HIV+ subjects were KIR3DS1 homozygotes, lacked a full length KIR2DS4 gene and carried the telomeric group B KIR haplotype motif, TB01. TB01 is characterized by the presence of KIR3DS1, KIR2DL5A, KIR2DS3/5 and KIR2DS1, in linkage disequilibrium with each other. We assessed which of the TB01 encoded KIR gene products contributed to NK cell responsiveness by stimulating NK cells from 8 HIV seronegative KIR3DS1 and TB01 motif homozygotes with 721.221 HLA null cells and evaluating the frequency of KIR3DS1+/-KIR2DL5+/-, KIR3DS1+/-KIR2DS1+/-, KIR3DS1+/-KIR2DS5+/- NK cells secreting IFN-γ and/or expressing CD107a. A higher frequency of NK cells expressing, versus not, KIR3DS1 responded to 721.221 stimulation. KIR2DL5A+, KIR2DS1+ and KIR2DS5+ NK cells did not contribute to 721.221 responses or modulate those by KIR3DS1+ NK cells. Thus, of the TB01 KIR gene products, only KIR3DS1 conferred responsiveness to HLA-null stimulation, demonstrating its ligation can activate ex vivo NK cells.

Natural killer (NK) cell receptor-HLA ligand genotype combinations associated with protection from HIV infection: investigation of how protective genotypes influence anti HIV NK cell functions.

The anti-HIV activity of natural killer (NK) cells could be induced fast enough to potentially prevent the establishment of HIV infection. Epidemiological studies identified two genotypes encoding NK receptors that contribute to NK cell function, that were more frequent in people who remained uninfected despite multiple HIV exposures than in HIV-susceptible subjects. NK cells from carriers of the *h/*y+B*57 genotype have higher NK cell functional potential and inhibit HIV replication in autologous HIV-infected CD4+ T cells (iCD4) more potently than those from carriers of non-protective genotypes. HIV suppression depends on the secretion of CC-chemokines that block HIV entry into CD4+ cells. NK cell education and the effect of HIV infection on iCD4 cell surface expression of MHC-I antigens both influenced NK cell responses to autologous iCD4. The second KIR3DS1 homozygous protective genotype encodes an activating receptor that upon interacting with its HLA-F ligand on iCD4 induces anti-viral activity.

Human Leukocyte Antigen C*12:02:02 and Killer Immunoglobulin-Like Receptor 2DL5 are Distinctly Associated with Ankylosing Spondylitis in the Taiwanese.

Human leukocyte antigen (HLA) class I ligands and Killer immunoglobulin-like receptors (KIRs) regulate the cytolytic activity of natural killer (NK) cells and certain T cells. We examined their genetic predisposition to disease susceptibility and clinical phenotypes in Taiwanese ankylosing spondylitis (AS) patients. KIR genotyping and Human Leucocyte Antigen C (HLA-C) sequencing were performed in 653 Taiwanese AS patients and 952 healthy controls. KIR genotype distributions and HLA-C allele frequencies were compared in patients and controls and among patients with and without HLA-B27 positivity, early age onset and spinal syndesmophytes. HLA-C alleles were functionally characterized using 3D structural modelling with peptide simulation. This study discovered that the HLA-C*12:02:02 allele (43.42% vs. 3.31%; p < 0.00001 odds ratio (OR), 16.88; 95% confidence intervals (CI): 11.27-25.28) confers a strong risk for Taiwanese AS development. The 3D modelling results identified four unique amino acid polymorphisms, Ala73, Trp156, Arg219 and Met304, that may affect the function of the HLA-C*12:02:02 allele. KIR2DL5 (p = 0.0047; pFDR = 0.0423) and the KIR Bx haplotype (p = 0.0000275) were protective against Taiwanese AS, while KIR 2DS4/1D (22 base pair truncated deletion; p = 0.0044; pFDR = 0.1998) appeared to be a risk factor for it. KIR2DL5 combined with the HLA-C1/C2 heterozygous genotype showed a protective effect (AS 5.97% vs. normal 11.66%; p = 0.002; pFDR = 0.0127, OR, 0.48 95% CI: 0.33-0.70); in contrast, KIR 2DS4/1D combined with the HLA-C1C1 homozygous genotype (AS 45.33% vs. normal 35.92%; p = 0.002; pFDR = 0.0127, OR, 1.48 95% CI: 1.21-1.81) represented a risk factor for AS development. Our data suggested that interactions between KIRs and their cognate HLA-C ligands may contribute to the pathogenesis of AS.

KIR2DL5 mutation and loss underlies sporadic dermal neurofibroma pathogenesis and growth.

Dermal neurofibromas (DNFs) are benign peripheral nerve sheath tumors thought to originate from Schwann cell progenitors. These tumors represent one of the hallmarks of the neurofibromatosis type 1 (NF1) tumor predisposition syndrome, where they can number in the thousands. While NF1-DNFs arise due to mutations in the NF1 gene, the vast majority of DNFs occur sporadically (sp-DNFs), where the genetic etiology is currently unknown. Herein, we employed whole-exome sequencing of sp-DNFs to identify a recurrent mutation in the KIR2DL5 gene, which codes for a protein suppressor of natural killer (NK) cell activity. While the function of KIR2DL5 outside of the immune system is unknown, we identified a KIR2DL5N173D mutation in three of nine sp-DNFs, resulting in loss of KIR2DL5 protein expression. In contrast, two of these subjects had unrelated tumors, which retained KIR2DL5 protein expression. Moreover, loss of KIR2DL5 expression was demonstrated in 15 of 45 independently-identified sp-DNFs. Consistent with its potential role as a negative growth regulator important for neurofibroma maintenance, ectopic KIR2DL5N173D expression in normal human Schwann cells resulted in reduced KIR2DL5 expression and increased cell proliferation. Similarly, KIR2DL5 short hairpin RNA knockdown (KD) decreased KIR2DL5 protein levels and increased cell proliferation, as well as correlated with PDGFRß and downstream RAS/AKT/mTOR hyperactivation. Importantly, inhibition of PDGFRß or AKT/mTOR activity in KIR2DL5-KD human Schwann cells reduced proliferation to control levels. Collectively, these findings establish KIR2DL5 as a new Schwann cell growth regulator relevant to sp-DNF pathogenesis, which links sporadic and NF1-associated DNFs through RAS pathway hyperactivation.

Identification of the novel KIR2DL4*00503 allele from a southern Chinese Han individual.

The novel KIR2DL4*00503 allele differs from the closest allele 2DL4*00501 by a single synonymous mutation.

Killer-cell immunoglobulin-like receptors and cytomegalovirus reactivation during late pregnancy.

Human cytomegalovirus (CMV) represents an important public health concern as it is associated with severe morbidity and mortality in transplant recipients, HIV-infected individuals and pregnant women given the risk of congenital infection. Congenital CMV is a leading cause of neurological sequelae, developmental delay and birth defects worldwide. Cytomegalovirus can be transmitted to the foetus following maternal infection or reactivation. NK cells expressing killer-cell immunoglobulin-like receptors (KIR) are part of the innate immune system and the first line of defence against viral incursions. Previous reports have shown that KIR genes are associated with CMV infections in the post-transplant setting. In this study, we set out to determine whether a protective effect of KIR genes over CMV infection is seen in Mexican pregnant women. Cytomegalovirus infection was assessed through nucleic acid testing in 200 pregnant women and 600 healthy blood donors comprising the Mexican mestizo reference population. Killer-cell immunoglobulin-like receptors and HLA-C genotypes were obtained from 200 pregnant women and 300 reference samples using a comprehensive PCR-SSP approach. We observed statistically lower carrier frequencies of cB03|tA01 gene-content haplotype, of cB03 haplotype motif, of the KIR2DL5 + 2DS3/2DS5 gene pair and of KIR2DL5 amongst CMV-positive pregnant women in comparison with those CMV negative. None of these were associated with CMV status in the reference population. Logistic regression analysis revealed that the most important factor determining CMV status during third-trimester pregnancies was the KIR2DL5 + 2DS3/2DS5 gene pair (OR 0.376 (95%CI 0.174, 0.811, P = 0.013). Our results indicate that CMV-protective KIR gene associations described in Caucasoid populations are also present in the genetically distinct Mexican mestizo population. Our results suggest that certain KIR gene combinations provide protection against CMV infections occurring during late-term pregnancies, a finding of utmost epidemiological importance given its implication with congenital CMV infections.

The investigation of killer cell immunoglobulin-like receptor genotyping in patients with systemic lupus erytematosus and systemic sclerosis.

Systemic lupus erythematosus (SLE) is an autoimmune disease characterised by the production of autoantibodies and the involvement of multiple organ systems. Systemic sclerosis (SSc) is another autoimmune disease that causes fibrosis. We will aim to analyse the role of killer cell immunoglobulin-like receptor (KIR) genotypes and their existence with the respective HLA ligands in patients with SLE and SSc. Forty-five SLE, 25 SSc and 40 healthy controls were included. We examined the presence/absence of KIR2DL1, 2DL2, 2DL3, 2DL4, 2DL5A, 2DL5B, 2DS1, 2DS1, 2DS2, 2DS3, 2DS4, 2DS5, 3DL1, 3DL2, 3DL3, 3DS1, 2DP1, 3DP1 and their known HLA ligands. In the SLE group, the KIR2DL5, KIR2DL5B and KIR2DS3 genes were significantly more frequent, and KIR2DL3 gene was significantly less than in controls (p values <0.05). In SSc patients, the KIR2DS3 gene was more frequent than in controls (p = 0.032). The KIR2DL3 gene was detected more frequently in controls while KIR2DS3 gene was more frequent in the patient group when SLE and SSc patients were combined (p values < 0.05). The KIR2DS2/HLA-C and KIR2DS2/HLA-C combinations were significantly more in both SLE and SSc groups than in controls. The KIR2DL2 and KIR2DL5B genes were protective from neurologic involvement in SLE patients (p values <0.05). The variations of some KIR genes such as KIR2DL5, KIR2DL5B, KIR2DS3 and KIR2DL3 may have a role in the pathogenesis of SLE and SSc. Also, the presence of KIR2DL2 and KIR2DL5B may cause major organ involvement, like neurologic involvement, in SLE.

KIR2DL5B genotype predicts outcomes in CML patients treated with response-directed sequential imatinib/nilotinib strategy.

Killer immunoglobulin-like receptors (KIRs) on natural killer (NK) cells have been shown to predict for response in chronic phase-chronic myeloid leukemia (CP-CML) patients treated with tyrosine kinase inhibitors. We performed KIR genotyping in 148 newly diagnosed CP-CML patients treated with a novel sequential imatinib/nilotinib strategy aimed at achievement of optimal molecular responses at defined time points. We found the presence of KIR2DL5B to be associated with inferior transformation-free survival and event-free survival and an independent predictor of inferior major molecular response (BCR-ABL1 ≤0.1%) and molecular response 4.5 (BCR-ABL1 ≤0.0032%). This suggests a critical early role for NK cells in facilitating response to imatinib that cannot be overcome by subsequent intensification of therapy. KIR genotyping may add valuable prognostic information to future baseline predictive scoring systems in CP-CML patients and facilitate optimal frontline treatment selection.

Characterisation of cell functions and receptors in Chronic Fatigue Syndrome/Myalgic Encephalomyelitis (CFS/ME).

BACKGROUND: Abnormal immune function is often an underlying component of illness pathophysiology and symptom presentation. Functional and phenotypic immune-related alterations may play a role in the obscure pathomechanism of Chronic Fatigue Syndrome/Myalgic Encephalomyelitis (CFS/ME). The objective of this study was to investigate the functional ability of innate and adaptive immune cells in moderate and severe CFS/ME patients. The 1994 Fukuda criteria for CFS/ME were used to define CFS/ME patients. CFS/ME participants were grouped based on illness severity with 15 moderately affected (moderate) and 12 severely affected (severe) CFS/ME patients who were age and sex matched with 18 healthy controls. Flow cytometric protocols were used for immunological analysis of dendritic cells, monocytes and neutrophil function as well as measures of lytic proteins and T, natural killer (NK) and B cell receptors. RESULTS: CFS/ME patients exhibited alterations in NK receptors and adhesion markers and receptors on CD4(+)T and CD8(+)T cells. Moderate CFS/ME patients had increased CD8(+) CD45RA effector memory T cells, SLAM expression on NK cells, KIR2DL5(+) on CD4(+)T cells and BTLA4(+) on CD4(+)T central memory cells. Moderate CFS/ME patients also had reduced CD8(+)T central memory LFA-1, total CD8(+)T KLRG1, naïve CD4(+)T KLRG1 and CD56(dim)CD16(-) NK cell CD2(+) and CD18(+)CD2(+). Severe CFS/ME patients had increased CD18(+)CD11c(-) in the CD56(dim)CD16(-) NK cell phenotype and reduced NKp46 in CD56(bright)CD16(dim) NK cells. CONCLUSIONS: This research accentuated the presence of immunological abnormalities in CFS/ME and highlighted the importance of assessing functional parameters of both innate and adaptive immune systems in the illness.