Genetic variants in the HLA-G region are associated with Kawasaki disease

Human Leukocyte Antigen-G Gene Polymorphism in Peninsular Malaysia: A Preliminary Report

Introduction: Expression of the nonclassical human leukocyte antigen (HLA)-G gene is upregulated in placenta during pregnancy. In other cells, HLA-G is upregulated during parasitic infections and allergic reactions. Polymorphism at the HLA-G gene locus has been reported for many populations, but so far not for any ethnic groups in Malaysia. In this survey, we screened for genetic variation in HLA-G genes from representative Malay, Chinese, and Indian individuals living in Peninsular Malaysia. Materials and Methods: Blood samples were obtained with informed consent, and ethnicity classes were assigned based on self-declared pedigree information. Exons 2, 3, and 4 of the HLA-G gene were amplified by polymerase chain reaction and subjected to Sanger sequencing. Results: The most common genotype in Malays and Indians was found to be HLA-G*01:01:01:01/01:01:01:01 with frequencies of 0.206 and 0.167, respectively, whereas the HLA-G*01:01:03:01/01:01:01:01 genotype was the one most frequently observed in Chinese (0.221). Based on this study, HLA-G*01:01:01:01 (0.427-0.448) is the most frequent HLA-G allele in the all three ethnic groups. In contrast, HLA-G*01:01:02:01 (0.186) was observed as the second most frequent HLA-G allele in Malays and HLA-G*01:04:01 in Chinese and Indians, (0.188-0.198, respectively). Several minor HLA-G alleles were detected at low frequency in Malays, Chinese, or Indians (HLA-G*01:01:05, 01:01:09, 01:04:02, and 01:04:03). These have only rarely, if ever, been reported in other population groups. Subsequent statistical analysis including using principal coordinate data mapping showed the Malays, Chinese, and Indians are distinct but quite closely related to one another as compared with other population groups from across Europe and Africa. Conclusion: The HLA-G population data collected in this study showed that the ancestrally unrelated Malays, Chinese, and Indians are genetically distinct. This new database provides a foundation for further studies to capture HLA-G allelic diversity in uncharacterized populations of Malaysia and for future attempts to identify their roles in disease resistance and susceptibility.

Association between maternal single-nucleotide polymorphisms in HLA-G gene and risk of preeclampsia

AIM

To determine the relationship between the maternal single-nucleotide polymorphisms (SNPs) in human leukocyte antigen G (HLA-G) gene and preeclampsia (PE), so as to provide guidance for the early risk prediction of PE.

METHODS

From October 2017 to October 2019, a total of 99 pregnant women were enrolled in this cross-sectional study. The PE group included 51 pregnant women with severe PE, and the control group included 48 pregnant women with normal delivery during the same period. DNA was extracted and the SNPs in HLA-G gene of the two groups were sequenced. Maternal SNPs in HLA-G gene affecting the occurrence of the PE were determined.

RESULTS

In this study, patients with PE had increased gravidity (p = .002), increased BMI before delivery (p = .004), reduced neonatal weight (p < .001), reduced gestational weeks (p < .001), reduced placental weight (p < .001), and increased proportion of cesarean section (p < .001). There were significant differences in SNPs at locus 29794467, 29796376, and 29799440 between the two groups (p < .05). In locus 29799440, patients with genotype CC had a lower risk of PE than patients with genotype TT (p = .047), with an odds ratio (OR) of 0.347(95%CI: 0.031, 3.881). And there was no significant difference in the risk of PE between patients with genotype CT, and those with genotype TT (p = .090) (OR = 2.344 95%CI: 0.187, 29.344).

CONCLUSION

There is an association between a SNP in locus 29799440 of the HLA-G gene and susceptibility of PE in Han Chinese pregnant women, and the risk of PE increases with genotype CT/TT in pregnant women.

HLA-C variants associated with amino acid substitutions in the peptide binding groove influence susceptibility to Kawasaki disease

Kawasaki disease (KD) is a pediatric vasculitis caused by an unknown trigger in genetically susceptible children. The incidence varies widely across genetically diverse populations. Several associations with HLA Class I alleles have been reported in single cohort studies. Using a genetic approach, from the nine single nucleotide variants (SNVs) associated with KD susceptibility in children of European descent, we identified SNVs near the HLA-C (rs6906846) and HLA-B genes (rs2254556) whose association was replicated in a Japanese descent cohort (rs6906846 p = 0.01, rs2254556 p = 0.005). The risk allele (A at rs6906846) was also associated with HLA-C*07:02 and HLA-C*04:01 in both US multi-ethnic and Japanese cohorts and HLA-C*12:02 only in the Japanese cohort. The risk A-allele was associated with eight non-conservative amino acid substitutions (amino acid positions); Asp or Ser (9), Arg (14), Ala (49), Ala (73), Ala (90), Arg (97), Phe or Ser (99), and Phe or Ser (116) in the HLA-C peptide binding groove that binds peptides for presentation to cytotoxic T cells (CTL). This raises the possibility of increased affinity to a "KD peptide" that contributes to the vasculitis of KD in genetically susceptible children.

Non-classical human leucocyte antigens in ankylosing spondylitis: possible association with HLA-E and HLA-F

OBJECTIVES

Ankylosing spondylitis (AS) is the most prevalent form of spondyloarthritis, with a known genetic association with the HLA-B27 molecule. The aim of this study was to assess the contribution of the HLA-G, HLA-E and HLA-F to AS susceptibility/protection in Portuguese patients with HLA-B27 AS and HLA-B27 unaffected controls.

METHODS

High-resolution typing of HLA-G, HLA-E and HLA-F was performed in 228 patients with HLA-B27 AS and 244 HLA-B27 unaffected controls. Allelic, genotypic and haplotypic frequencies were compared between cohorts. To replicate the results, single nucleotide polymorphisms (SNPs) in HLA-E and HLA-F genes were typed in Australian cohorts. For further confirmation, a group of European-descent patients with AS and unaffected controls were genotyped for Major Histocompatibility Complex SNPs using the Illumina microarray.

RESULTS

In the Portuguese population, no significant differences were found in HLA-G. For HLA-E, a significant difference was detected for the genotype HLA-E*01:01:01/01:03:01 (p=0.009; pc=0.009; OR=0.51), with a protection effect. For HLA-F, significant differences were detected in the allele HLA-F*01:01:02 (p=0.0049; pc=0.0098; OR=0.60) and corresponding SNP rs2075682 (p=0.0004; pc=0.0008; OR=0.53), suggesting protection and in the genotype HLA-F*01:01:01/01:03:01 (p=0.011; pc=0.043; OR=2.00), suggesting a susceptibility effect. Three G-E-F haplotypes with significant differences were detected but occur in a very small number of individuals. The only significant differences detected in the replication studies were for HLA-E rs1059510 in the Australians and for HLA-F rs1736924 in the European-descent cohorts.

CONCLUSION

Our results reveal suggestive AS protective and susceptibility effects from both HLA-E and HLA-F loci, however with population differences. To our knowledge, this is the first study showing association of HLA-F with AS.

Genetic variants in PLCB4/PLCB1 as susceptibility loci for coronary artery aneurysm formation in Kawasaki disease in Han Chinese in Taiwan

Kawasaki disease (KD) is an acute, inflammatory, and self-limited vasculitis affecting infants and young children. Coronary artery aneurysm (CAA) formation is the major complication of KD and the leading cause of acquired cardiovascular disease among children. To identify susceptible loci that might predispose patients with KD to CAA formation, a genome-wide association screen was performed in a Taiwanese KD cohort. Patients with both KD and CAA had longer fever duration and delayed intravenous immunoglobulin treatment time. After adjusting for these factors, 100 susceptibility loci were identified. Four genes were identified from a single cluster of 35 using the Ingenuity Pathway Analysis (IPA) Knowledge Base. Silencing KCNQ5, PLCB1, PLCB4, and PLCL1 inhibited the effect of lipopolysaccharide-induced endothelial cell inflammation with varying degrees of proinflammatory cytokine expression. PLCB1 showed the most significant inhibition. Endothelial cell inflammation was also inhibited by using a phospholipase C (PLC) inhibitor. The single nucleotide polymorphism rs6140791 was identified between PLCB4 and PLCB1. Plasma PLC levels were higher in patients with KD and CC+CG rs6140791genotypes, and these genotypes were more prevalent in patients with KD who also had CAA. Our results suggest that polymorphism of the PLCB4/B1 genes might be involved in the CAA pathogenesis of KD.

Clinical correlates of human leucocyte antigen (HLA)-G in systemic sclerosis

Human leucocyte antigen (HLA)-G has a tolerogenic function and could play a role in the pathogenesis of immune-mediated diseases, including systemic sclerosis (SSc). The aim of this study was to evaluate HLA-G serum expression (sHLA-G) and the HLA-G gene 14 base pairs (bp) insertion/deletion (del(-)/del(+)) polymorphism in patients with Ssc, to search for possible associations with clinical and laboratory variables. sHLA-G was measured by enzyme-linked immunosorbent assay (ELISA) in sera from 77 patients with SSc and 32 healthy donors (HD); the 14 bp del(-)/del(+) polymorphism was evaluated by polymerase chain reaction (PCR) amplification of peripheral blood mononuclear cells (PBMC) genomic DNA. Receiver operating characteristics (ROC) analysis identified the HLA-G cut-off that best discriminated dichotomized clinical and serological variables, that was subsequently employed to subdivide SSc patients into HLA-G high (HLA-G(+)) and low (HLA-G(-)) profile groups. sHLA-G were not statistically different between SSc patients and HD, nor between distinct SSc autoantibody subsets. Subdividing SSc patients by HLA-G positivity or negativity yielded significant differences for the modified Rodnan skin score (mRss) (P = 0.032), 'general' (P = 0.031) and 'kidney' (P = 0.028) Medsger severity scores (MSS) and disease activity index, and especially Δ heart/lung (P = 0.005). A worse 'general' MSS (P = 0.002) and Δ heart/lung (P = 0.011) were more frequent in the low sHLA-G group. These two variables and mRss were associated with sHLA-G levels at logistic regression analysis. Treatment had no influence on sHLA-G. Moreover, a higher frequency of scleredema was detected in the del(+)/del(+) than the del(-)/del(+) group (P = 0.04). These data suggest modulatory effects of sHLA-G on SSc. Prospective studies are needed to investigate a role in predicting the disease course.

Imputation of class I and II HLA loci using high-density SNPs from ImmunoChip and their associations with Kawasaki disease in family-based study

Kawasaki disease (KD) is the leading cause of acquired heart disease in children in most developed countries including the United States. The etiology of KD is not known; however, epidemiological and immunological data suggest infectious or immune-related factors in the manifestation of the disease. Further, KD has several hereditary features that strongly suggest a genetic component to disease pathogenesis. Human leucocyte antigen (HLA) loci have also been reported to be associated with KD, but results have been inconsistent, in part, because of small study samples and varying linkage disequilibrium (LD) patterns observed across different ethnic groups. To maximize the informativeness of single nucleotide polymorphism (SNP) genotypes in the major histocompatibility (MHC) region, we imputed classical HLA I (A, B, C) and HLA II (DRB1, DQA1, DQB1) alleles using SNP2HLA method from genotypes of 6700 SNPs within the extended MHC region contained in the ImmunoChip among 112 White patients with KD and their biological parents from North America and tested their association with KD susceptibility using the transmission disequilibrium test. Mendelian consistency in the trios suggested high accuracy and reliability of the imputed alleles (class I = 97.5%, class II = 96.6%). While several SNPs in the MHC region were individually associated with KD susceptibility, we report over-transmission of HLA-C*15 (z = +2.19, P = 0.03) and under-transmission of HLA-B*44 (z = -2.49, P = 0.01) alleles from parents to patients with KD. HLA-B*44 has been associated with KD in other smaller studies, and both HLA-C*15 and HLA-B*44 have biological mechanisms that could potentially be involved in KD pathogenesis. Overall, inferring HLA loci within the same ethnic group, using family-based information is a powerful approach. However, studies with larger sample sizes are warranted to evaluate the correlations of the strength and directions between the SNPs in MHC region and the imputed HLA alleles with KD.

HLA-G Molecules in Autoimmune Diseases and Infections

Human leukocyte antigen (HLA)-G molecule, a non-classical HLA-Ib molecule, is less polymorphic when compared to classical HLA class I molecules. Human leukocyte antigen-G (HLA-G) was first detected on cytotrophoblast cells at the feto-maternal interface but its expression is prevalent during viral infections and several autoimmune diseases. HLA-G gene is characterized by polymorphisms at the 3' un-translated region and 5' upstream regulatory region that regulate its expression and are associated with autoimmune diseases and viral infection susceptibility, creating an unbalanced and pathologic environment. This review focuses on the role of HLA-G genetic polymorphisms, mRNA, and protein expression in autoimmune conditions and viral infections.

Association between GRIN3A gene polymorphism in Kawasaki disease and coronary artery aneurysms in Taiwanese children

Kawasaki disease (KD) is pediatric systemic vasculitis with the classic complication of coronary artery aneurysm (CAA). It is the leading cause of acquired cardiovascular diseases in children. Some severe cases present with multi-organ involvement or neurological dysfunction. To identify the role of the glutamate receptor, ionotropic, N-methyl-d-aspartate 3A (GRIN3A) in KD, we investigated genetic variations in GRIN3A in a Taiwanese cohort of 262 KD patients (76 with and 186 without CAA complications). We used univariate and multivariate regression analyses to identify the associations between clinical characteristics and GRIN3A genetic variations in KD. According to univariate regression analysis, CAA formation in KD was significantly associated with fever duration (p < 0.0001), first Intravenous immunoglobulin (IVIG) used (days after day one of fever) (p < 0.0001), and the GRIN3A (rs7849782) genetic variant (p < 0.001). KD patients with GG+GC genotype showed a lower rate of developing CAA (GG+GC genotype: odds ratio = 0.26; 95% CI = 0.14–0.46). Significant associations were identified between KD with CAA complication and the GRIN3A (rs7849782) genetic variant by using multivariate regression analysis. Specifically, significant correlations were observed between KD with CAA complications and the presence of GG+GC genotypes for the GRIN3A rs7849782 single-nucleotide polymorphism (full model: odds ratio = 0.25; 95% CI = 0.14–0.46). Our results suggest that a polymorphism of the GRIN3A gene may play a role in KD pathogenesis.

PSORS1C1 may be involved in rheumatoid arthritis

PSORS1C1/CDSN is a susceptibility gene for psoriasis. Both psoriasis and rheumatoid arthritis (RA) are autoimmune diseases. This study investigated whether PSORS1C1/CDSN was involved in RA. The TagSNPs rs3130983, rs3778638 and rs4959053 in the PSORS1C1/CDSN locus were shown to predict susceptibility to RA in two independent RA cohorts using a TaqMan genotyping assay and Sequenom MassARRAY. The expression of PSORS1C1/CDSN was determined with western blotting and ELISA. Cultured synovial fibroblasts from RA patients (RASF) were treated with anti-PSORS1C1 siRNA. The TaqMan genotyping assay demonstrated significant differences in the rs3130983 and rs4959053 allele frequencies (p = 0.002001 and 1.74E-07, respectively) and genotype frequencies (0.010503 and 1.07E-06, respectively) between the RA patients and controls. Sequenom MassARRAY results indicated that SNP rs3778638 allele frequency and genotype frequency were significantly associated with RA (p = 7.35E-05 and 0.000357, respectively). Western blotting revealed a significant increase in expression of PSORS1C1 in RA synovial tissues, and ELISA detected high levels of PSORS1C1 and CDSN in the blood of RA patients. PSORS1C1-siRNA treatment significantly decreased the PSORS1C1 expression, IL-17 level, Il-1β level and cell proliferation in RASF. These results suggest that PSORS1C1 might play an important role in the development of RA.

Understanding the pathogenesis of Kawasaki disease by network and pathway analysis

Kawasaki disease (KD) is a complex disease, leading to the damage of multisystems. The pathogen that triggers this sophisticated disease is still unknown since it was first reported in 1967. To increase our knowledge on the effects of genes in KD, we extracted statistically significant genes so far associated with this mysterious illness from candidate gene studies and genome-wide association studies. These genes contributed to susceptibility to KD, coronary artery lesions, resistance to initial IVIG treatment, incomplete KD, and so on. Gene ontology category and pathways were analyzed for relationships among these statistically significant genes. These genes were represented in a variety of functional categories, including immune response, inflammatory response, and cellular calcium ion homeostasis. They were mainly enriched in the pathway of immune response. We further highlighted the compelling immune pathway of NF-AT signal and leukocyte interactions combined with another transcription factor NF- κ B in the pathogenesis of KD. STRING analysis, a network analysis focusing on protein interactions, validated close contact between these genes and implied the importance of this pathway. This data will contribute to understanding pathogenesis of KD.

Rate, associated factors and outcomes of recurrence of Kawasaki disease in Ontario, Canada

BACKGROUND

Previous studies on recurrence of Kawasaki disease (KD) have mostly been limited to Japan, which has an incidence of KD 8-10-fold higher than North America. The aim of the present study was to determine the rate of KD recurrence for patients in Ontario, to identify factors potentially associated with increased odds of recurrence, and to compare the clinical course and outcomes of index and recurrent KD episodes.

METHODS

Review was undertaken of all patients with recurrence of KD identified in Ontario, Canada, from 1995 to 2006. All patients with recurrence of KD (defined as at least three clinical signs of KD in addition to fever ≥ 5 days), presenting ≥ 14 days after the return to baseline from the index episode were included.

RESULTS

A total of 1010 patients were followed for 5786 patient-years. During this period a total of 17 recurrent episodes in 16 patients were identified at a median of 1.5 years after the initial episode (2 weeks-5 years). Rate of recurrence of KD was 2.9 episodes/1000 patient-years, which is higher than the expected annual incidence of KD in the same age group (26.2/100,000 per year). No factors associated with increased risk of recurrence were identified, perhaps due to the small number of events. Clinical course and outcomes of the index and recurrent KD episodes were similar.

CONCLUSIONS

A previous history of KD should increase the index of suspicion for future episodes of KD to allow for rapid recognition, treatment and to achieve optimal outcomes.

[Kawasaki disease in children and adolescents]

Kawasaki disease (KD) is a systemic vasculitis of unknown etiology. The diagnostic criteria are fulfilled with fever of unknown origin and 4 of the following 5 criteria: bilateral conjunctival injection, cervical lymphadenopathy, polymorphous rash, oral mucous membrane changes (injected lips, strawberry tongue) and peripheral extremity changes (erythema, edema, desquamation). If less than 4 criteria are found incomplete KD can be diagnosed. The therapy is 2 g/kg body weight single dose intravenous immunoglobulin and acetylsalicylic acid (ASS). In the long-term follow-up the main focus is on the coronary arteries because coronary changes play a key role in the intensity of long-term management. There is some evidence that KD is a risk factor for cardiovascular diseases in adults.

Major histocompatibility complex class I chain-related gene polymorphisms: associated with susceptibility to Kawasaki disease and coronary artery aneurysms

BACKGROUND

Kawasaki disease (KD) involves a complex interaction of immunoinflammatory process, cytokine activation, and genetic factors. We aimed to investigate whether genetic variations in a major histocompatibility complex (MHC) class could be used as markers of susceptibility in KD and coronary artery aneurysm lesions (CALs).

METHODS

Individuals were divided into following groups: (1) normal controls; (2) KD with CAL; (3) KD without CAL. Polymorphisms for MHC class I chain-related genes A (MICA) (rs2301747, rs2256184, rs2848716), MICB (rs2855804, rs3132464, rs2516400), BAT3 (rs750332), MSH5 (rs1150793), and chromosome 6 open reading frame 27 (C6orf27, rs707928) were genotyped with polymerase chain reaction and the TaqMan(®) allelic discrimination assay. Genotypes, alleles, and haplotype in each group were compared.

RESULTS

Genotype and allele frequency of MICB*rs2516400 polymorphisms in each group were significantly different. MICB (rs2516400)*C-related genotypes/alleles are correlated with development of KD and CAL. Proportions of rs2516400*TT/TC/CC were (1) 1/39/60%, (2) 0/0/100%, and (3) 0/0/100%. Other single-nucleotide polymorphisms were not associated with KD susceptibilities. Haplotypes (rs2301747-rs2256184-rs2848716-rs2855804-rs3132464-rs2516400-rs750332-rs1150793-rs707928) G-G-G-C-T-C-T-A-A, C-A-G-T-T-C-T-A-A, and G-G-G-C-C-C-T-A-A were associated with higher susceptibilities for KD. The G-G-G-T-T-T-T-G-G and C-G-G-T-T-T-T-A-A haplotypes were associated with lower susceptibilities.

CONCLUSION

MICB*rs2516400 polymorphisms and some MHC class I-related haplotypes are associated with KD susceptibility. MICB and MHC class I genetic variations might contribute to the pathogenesis of KD and CAL.

Human lymphocyte antigen B-associated transcript 2, 3, and 5 polymorphisms and haplotypes are associated with susceptibility of Kawasaki disease and coronary artery aneurysm

CAPSULE

HLA-B associated transcript (BAT) 2, 3, and 5 polymorphisms and haplotypes are associated with Kawasaki disease (KD) and coronary artery aneurysm (CAA) formations.

OBJECTIVE

KD, an acute vasculitis with unknown etiology, involves a complex interaction of immuno-inflammatory process, cytokines activation, and genetic factors. We aimed to investigate if genetic variants of human lymphocyte antigen (HLA)-BAT2, 3, and 5 (BAT2, 3, and 5) could be used as markers of susceptibility in KD and CAA.

METHODS

Individuals were divided into three groups: (1) normal controls; (2) KD with CAA; and (3) KD without CAA. Polymorphisms for BAT2 (-8671, 16483), BAT3 (8854, 2-24), and BAT5 (22655, 9569) were genotyped by PCR system with TaqMan allelic discrimination assay. Genotype/allelic frequencies and haplotypes (BAT2(-8671)-BAT2(16483)-BAT3(8854)-BAT3(2-24)-BAT5(22655)-BAT5(9569)) in each group were compared.

RESULTS

Genotype distribution and allele frequency of BAT2 -8671, BAT3 8854, and BAT5 22655, 9569 polymorphisms in each group were significantly different. BAT2 -8671*G, BAT3 8854*C, BAT5 22655*C, and 9569*A-related genotypes and alleles are correlated with the developments of KD and CAA. BAT haplotypes of ATTGTG and ATCATG are associated with higher susceptibilities of KD with CAA susceptibility.

CONCLUSION

BAT2 -8671, BAT3 8854, and BAT5 22655, 9569 polymorphisms as well as BAT haplotypes (ATTGTG and ATCATG) might be associated with higher KD susceptibility and CAA formation. HLA-B region polymorphisms might contribute to the pathogenesis of KD and CAA.

Human lymphocyte antigen B-associated transcript 2, 3, and 5 polymorphisms and haplotypes are associated with susceptibility of Kawasaki disease and coronary artery aneurysm

CAPSULE

HLA-B associated transcript (BAT) 2, 3, and 5 polymorphisms and haplotypes are associated with Kawasaki disease (KD) and coronary artery aneurysm (CAA) formations.

OBJECTIVE

KD, an acute vasculitis with unknown etiology, involves a complex interaction of immuno-inflammatory process, cytokines activation, and genetic factors. We aimed to investigate if genetic variants of human lymphocyte antigen (HLA)-BAT2, 3, and 5 (BAT2, 3, and 5) could be used as markers of susceptibility in KD and CAA.

METHODS

Individuals were divided into three groups: (1) normal controls; (2) KD with CAA; and (3) KD without CAA. Polymorphisms for BAT2 (-8671, 16483), BAT3 (8854, 2-24), and BAT5 (22655, 9569) were genotyped by PCR system with TaqMan allelic discrimination assay. Genotype/allelic frequencies and haplotypes (BAT2(-8671)-BAT2(16483)-BAT3(8854)-BAT3(2-24)-BAT5(22655)-BAT5(9569)) in each group were compared.

RESULTS

Genotype distribution and allele frequency of BAT2 -8671, BAT3 8854, and BAT5 22655, 9569 polymorphisms in each group were significantly different. BAT2 -8671*G, BAT3 8854*C, BAT5 22655*C, and 9569*A-related genotypes and alleles are correlated with the developments of KD and CAA. BAT haplotypes of ATTGTG and ATCATG are associated with higher susceptibilities of KD with CAA susceptibility.

CONCLUSION

BAT2 -8671, BAT3 8854, and BAT5 22655, 9569 polymorphisms as well as BAT haplotypes (ATTGTG and ATCATG) might be associated with higher KD susceptibility and CAA formation. HLA-B region polymorphisms might contribute to the pathogenesis of KD and CAA.

Repeated systematic surveillance of Kawasaki disease in Ontario from 1995 to 2006

BACKGROUND

Rising incidences of Kawasaki disease (KD) have been reported worldwide. Reported herein are the results of 4 triennial KD surveillances conducted in Ontario.

METHODS

Between 1995 and 2006 all hospitals in Ontario were asked on 4 occasions to identify all patients with discharge diagnoses of KD and report incident cases.

RESULTS

The latest surveillance identified 697 new KD patients (100% response rate) for a total of 2378 KD patients through all 4 surveillances. Yearly incidence was 26.2/100,000 for <5 years old, 6.7/100,000 for 5-9 years old and 0.9/100,000 for 10-14 years old. KD incidence significantly increased from 1995 to 2006, although the increase seemed to plateau between the 3rd and 4th surveillance. There was an increase in the proportion of patients diagnosed with incomplete KD and a significant reduction in the rate of coronary artery abnormalities, possibly due to better disease recognition and treatment. Hospitals reporting <20 cases per surveillance were found to be more likely to report cases with incomplete KD. These patients were also less likely to be treated with i.v. immunoglobulin and aspirin but were more likely to be treated with antibiotics, suggesting uncertainties regarding diagnosis and management of KD patients in those centers.

CONCLUSIONS

The incidence of KD in Ontario is possibly one of the highest outside of Asia and has been rising since 1995. Although the most recent surveillance demonstrated improved cardiac outcomes, treatment delays or absence thereof continue to be a problem. Effective diagnosis and prompt treatment remain critical aspects of KD management.

The role of Qa-2, the functional homolog of HLA-G, in a Behcet's disease-like mouse model induced by the herpes virus simplex

Background

It has been suggested that the HLA-G molecule is a genetic risk factor for Behcet's disease (BD). In this study, we evaluated the level of Qa-2, a murine nonclassical class I MHC molecule and possible functional homolog of HLA-G, to determine if it was associated with various symptoms of BD-like mice. In addition, we investigated siRNA (small interfering RNA) treatment to determine if it inhibited Qa-2 expression, thereby changing the symptoms of mice.

Methods

RNA interference (RNAi) and vector transfection were employed to manipulate gene expression in vivo in mice. siRNA (small interfering RNA) or Qa-2 expression vector was applied to inhibit or up-regulate Qa-2 expression, respectively.

Results

The Qa-2 levels in granulocytes were lower in BD-like mice than in normal controls. The silencing of Qa-2 by intravenous injection of siRNA (500 nmol/mouse, 4 times at 3-day intervals) specifically reduced the Qa-2 levels and worsened the BD-like symptoms.

Conclusions

Silencing Qa-2 by injecting siRNA into mice resulted in deterioration of symptoms in BD-like mice.

Involvement of tryptophan hydroxylase 2 (TPH2) gene polymorphisms in susceptibility to coronary artery lesions in Korean children with Kawasaki disease

Kawasaki disease (KD) is an acute vasculitis of childhood that predominantly affects the coronary arteries. We investigated single nucleotide polymorphisms (SNPs) of the tryptophan hydroxylase 2 (TPH2) gene as risk factors for KD with coronary artery lesions (CALs) in Korean children. We genotyped two SNPs [rs7305115 (exon 7) and rs4290270 (exon 9)] using direct sequencing in 101 KD and 256 control subjects. To analyze the genetic data, SNPStats, SNPAnalyzer, and Helixtree programs were used. The genotype analysis of rs7305115 and rs4290270 showed no significant differences between KD and control groups. However, we found a statistically significant association between the two SNPs and the development of CALs in KD (p < 0.05). The minor homozygous genotype (rs7305115, AA genotype and rs42901270, AA genotype) of each SNP showed increased susceptibility to risk of CALs in KD patients. These results suggest that TPH2 may be associated with the development of KD with CALs in Korean children.

HLA-G: a human pregnancy-related immunomodulator

In human pregnancies mothers and their embryo/fetuses are invariably genetically different. Thus, attenuation of the adaptive maternal immune response, which is programmed to reject 'foreign' entities, is required for pregnancy to be initiated and maintained. Unexpectedly, given the propensity of the immune system to dispose of non-self entities, at least 50% of expected human pregnancies reliably go forward. This indicates that to a large extent, effective systems of tolerance have evolved. Although overlapping and redundant mechanisms of tolerance have been identified, production of HLA-G by trophoblast cells derived from the external trophectoderm layer of the blastocyst appears to be of major importance. At this point in time, no pregnancies in which all of the proteins derived from the HLA-G gene are absent have as yet been reported. Many studies have shown that both membrane-bound and soluble isoforms of the proteins derived from this HLA class Ib gene are produced by placental trophoblast cells, with consequences that include but are not restricted to immune suppression at the maternal-fetal interface. Here we report new studies that are leading to a better understanding of the HLA-G proteins, their unique structures, unusual modes of regulation, diverse functions, and potential for use in diagnostic and therapeutic procedures related to suboptimal fertility in women.

Microparticle encoding technologies for high-throughput multiplexed suspension assays

The requirement for analysis of large numbers of biomolecules for drug discovery and clinical diagnostics has driven the development of low-cost, flexible and high-throughput methods for simultaneous detection of multiple molecular targets in a single sample (multiplexed analysis). The technique that seems most likely to satisfy all of these requirements is the multiplexed suspension (bead-based) assay, which offers a number of advantages over alternative approaches such as ELISAs and microarrays. In a bead based assay, different probe molecules are attached to different beads (of a few tens of microns in size), which are then reacted in suspension with the target sample. After reaction, the beads must be identifiable in order to determine the attached probe molecule, and thus each bead must be labelled (encoded) with a unique identifier. A large number of techniques have been proposed for encoding beads. This critical review analyses each technology on the basis of its ability to fulfil the practical requirements of assays, whilst being compatible with low-cost, high-throughput manufacturing processes and high-throughput detection methods. As a result, we identify the most likely candidates to be used for future integrated device development for practical applications.