Human platelet alloantigens HPA-1, HPA-2, and HPA-3 polymorphisms associated with extent of severe coronary artery disease

The contribution of human platelet antigen (HPA)-1 (GPIIb/IIIa), HPA-2 (GPIb/IX), and HPA-3 (GPIIb/IIIa) polymorphisms to the risk of coronary artery disease (CAD) was investigated in 341 CAD patients and 316 matched control subjects. HPA genotyping was performed by PCR-SSP. Regression analysis was employed in assessing the contribution of these variants to CAD risk. The frequency of HPA-1b (P = .009) and HPA-3b (P = .004) alleles, and HPA-1a/1b (P = .045), HPA-1b/1b (P = .007), and HPA-3b/3b (P = .008) genotypes were higher in patients than control subjects. No significant association was demonstrated between the HPA variants and 1-, 2- and 3-vessel disease. HPA-1b/2a/3b (Pc = .021) and HPA-1b/2b/3a (Pc = .002) haplotypes were positively associated with CAD, thereby conferring a disease susceptibility nature to these haplotypes. Multivariate analysis confirmed the positive association of HPA-1b/2a/3b (aOR = 3.72; 95% CI = 1.49–9.28), and in addition identified HPA-1b/2a/3a (aOR = 2.49; 95% CI = 1.06–5.86) to be positively associated with CAD, after adjusting for a number of covariates. Our results demonstrate positive association of HPA variants and specific HPA-1/HPA-2/HPA-3 haplotypes with CAD in Tunisians.     

In vivo platelet activation in atherothrombotic stroke is not determined by polymorphisms of human platelet glycoprotein IIIa or Ib

Platelet membrane glycoprotein polymorphisms are candidate risk factors for thrombosis, but epidemiological data are conflicting. Thus, demonstration of a genotype-dependent alteration in function is desirable to resolve these inconsistencies. We investigated in vivo platelet activation in acute thrombosis and related this to platelet genotype. Frequencies of the 1b and 2b alleles of the HPA 1a/1b and HPA 2a/2b platelet glycoprotein polymorphisms were determined in 150 (52 men/98 women, mean age 58.3 years) patients with atherothrombotic stroke, and the influence of genotype on markers of platelet activation was assessed. Platelet P-selectin (CD62P) expression and fibrinogen binding was measured using whole blood flow cytometry within 24 h of stroke and 3 months later in 77 patients who provided a repeat blood sample. Results were compared with matched controls. Neither the 1b allele [allele frequency 0.11 vs. 0.13, odds ratio (OR) confidence interval (CI) 0.8 (0.5-1.3)] nor the 2b allele [0.09 vs. 0.07, OR (CI) 1.4 (0.8-2.4)] was significantly over-represented in patients. Increased numbers of activated platelets were found following stroke (acute mean P-selectin expression 0.64% vs. control 0.35%, P < 0.001; acute mean fibrinogen binding 1.6% vs. control 0.9%, P < 0.001). Activation persisted in the convalescent phase (P < 0.001 and P = 0.005 vs. controls for P-selectin and fibrinogen respectively). Expression of P-selectin and fibrinogen was not influenced by either the HPA 1a/1b genotype (P > 0.95 for each marker, Scheffe's test) or the 2a/2b genotype (P > 0.95 for each). Although persisting platelet activation is seen in atherothrombotic stroke, it is independent of HPA 1a/1b and 2a/2b genotypes. These data suggest an underlying prothrombotic state, but do not support the polymorphisms studied as risk factors for thrombotic stroke in this population.     

Allele Frequencies of Human Platelet Antigen 1, 2, 3, and 5 Systems in Patients with Chronic Refractory Autoimmune Thrombocytopenia and in Normal Persons

BACKGROUND AND OBJECTIVES: Chronic refractory autoimmune thrombocytopenic purpura (AITP) is an autoimmune disorder due to autoantibodies against platelet glycoproteins (GP). Human platelet alloantigenic (HPA) systems are distributed to different platelet GPs. We carried out genotyping of diallelic HPA-1, -2, -3, and -5 systems to clarify potential associations between HPA alleles and the development of chronic refractory AITP. PATIENTS AND METHODS: DNA was isolated from 33 unrelated German patients with chronic refractory AITP and from 80 randomly selected German blood donors to determine the phenotype and allele frequencies for the HPA-1, -2, -3, and -5 systems. Fragments carrying the polymorphic sequences corresponding to those alleles were amplified by the polymerase chain reaction and further characterized by restriction analysis. RESULTS: Whereas HPA-1, -3, and -5 allele frequencies were identical in 33 patients with chronic refractory AITP and in controls, HPA-2 allele frequencies showed a statistically significant difference (p = 0.017). In our group of patients, the HPA-2a allele frequency was 100%, but HPA-2b was not seen. In contrast, the allele frequency of HPA-2a in the control group was 92% (n = 147), and in HPA-2b it was 8% (n = 13). CONCLUSION: This study suggests an association between the HPA-2a allele and chronic refractory AITP. The HPA-2a allele may be involved in the formation of an AITP-specific autoepitope.     

武汉地区人群血小板特异性基因(HPA-1～17)的多态性分析

目的:研究武汉地区人群HPA-1~17基因的多态性及其表达频率,建立HPA基因型资料库。方法:采用序列特异性引物-聚合酶链反应(SSP-PCR)对284名健康的已加入中华骨髓库的血小板捐献者HPA基因进行分型,计算基因型频率、基因频率。结果:武汉地区健康血小板捐献者中检测出HPA-a基因中的1a~17a基因;各基因独立的分布频率中,HPA-1a(98.77%)、2a(97.01%)、3a(59.68%)、4a(99.82%)、5a(99.82%)、6a(98.42%)、15a(49.47%),HPA-7a~14a、16a和17a均为100%。仅检测出HPA-b基因中HPA-1b(1.23%)、2b(2.99%)、3b(40.32%)、4b(0.18%)、5b(0.18%)、6b(1.58%)、15b(50.53%),未检测出HPA-7b~14b、16b和17b。文中调查和分析了HPA基因组合型及其频率,发现武汉地区HPA基因有28种组合型,其中仅有3种基因组合型频率10%(44%),另外25种基因组合型的频率均9%(56%)。在与国内外不同地区人群HPA基因多态性分布的比较分析中发现,武汉地区人群中HPA基因频率与上海、成都地区人群没有差异性,与美国、英国、欧洲人群有较有明显差异,而与日本人群的差异较小。结论:HPA-3、15系统具有多态性,在随机血小板输注中,供受者HPA-3、HPA-15系统不配合的机会分别为36.54%、37.50%,是HPA配合性输注关注重点。HPA基因多态性研究数据有利于指导地区性血小板供者库库容的设计,配合临床开展选择适合性血小板输注具有重要意义。     

HPA-1a phenotype-genotype discrepancy reveals a naturally occurring Arg93Gln substitution in the platelet beta 3 integrin that disrupts the HPA-1a epitope

A single nucleotide polymorphism (SNP) at position 196 in the beta 3 integrin causes a Leu33Pro substitution in the mature protein. Alloimmunization against the beta 3Leu33 form (human platelet antigen [HPA]-1a, Pl(A1), Zw(a)) in patients who are beta 3Pro33 homozygous (HPA-1b1b, Pl(A2A2), Zw(bb)) causes neonatal alloimmune thrombocytopenia, posttransfusion purpura, or refractoriness to platelet transfusion. Studies with recombinant proteins have demonstrated that amino acids 1 to 66 and 288 to 490 of the beta 3 integrin contribute to HPA-1a epitope formation. In determining the HPA-1a status of more than 6000 donors, we identified a donor with an HPA-1a(weak) phenotype and an HPA-1a1b genotype. The platelets from this donor had normal levels of surface alpha IIb beta 3 but reacted only weakly with monoclonal and polyclonal anti-HPA-1a by whole blood enzyme-linked immunosorbent assay (ELISA), flow cytometry, and sandwich ELISA. We reasoned that an alteration in the primary nucleotide sequence of the beta 3Leu33 allele of this donor was disrupting the HPA-1a epitope. In agreement with this hypothesis, sequencing platelet RNA-derived alpha IIb and beta 3 cDNA identified a novel G/A SNP at position 376 of the beta 3 integrin that encodes for an Arg93Gln replacement in the beta 3Leu33 allele. Coexpression of the beta 3Leu33Gln93 encoding cDNA in Chinese hamster ovary cells with human alpha IIb cDNA showed that the surface-expressed alpha IIb beta 3 reacted normally with beta 3 integrin-specific monoclonal antibodies but only weakly with monoclonal anti-HPA-1a. Our results show that an Arg93Gln mutation in the beta 3Leu33 encoding allele disrupts the HPA-1a epitope, suggesting that Arg93 contributes to the formation of the HPA-1a B-cell epitope.     

Gene frequencies of the HPA-1 to HPA-8w platelet antigen alleles in Taiwanese,Indonesian, and Thai

Human platelet antigen (HPA) systems consist of more than eight biallelic antigen polymorphisms in which a base pair substitution leads to change in an amino acid of a glycoprotein expressed on the platelet. HPA typing is essential in the diagnosis and treatment for a variety of diseases. We developed a polymerase chain reaction (PCR)-based method to detect HPA-1 through HPA-8w. In this method, the amplified PCR products were used to recognize the polymorphism after restriction enzyme digestions. Among 295 Taiwanese, 107 Indonesian, and 137 Thai subjects studied, HPA-1a, 2a, 4a, 5a, 6a, 7aw, and 8aw genes were present in every sample tested. HPA-1b, 2b, 4b, 5b, and 6b were rarely found among subjects. Only monomorphic HPA-7aw and 8aw alleles were noted in the samples. HPA-3a and 3b alleles showed frequencies of 0.595/0.405, 0.504/0.496, and 0.507/0.493 in Taiwanese, Indonesian, and Thai subjects, respectively. Our report is the first PCR-based method to detect most of the HPA antigen variants in Taiwanese, Indonesian, and Thai. The genomic typing results were also confirmed by direct sequencing for uncertain and some representative cases. The prevalence rates of HPA-1, 2, 3, 4, and 5 in this study were also consistent with other previous reports using different methods.     

Interaction of angiotensin-converting enzyme and apolipoprotein E gene polymorphisms in ischemic stroke involving large-vessel disease

A relationship between apolipoprotein E (Apo E) genotype and angiotensin-converting enzyme (ACE) insertion-deletion (Ins-Del) mutation and stroke was suggested. We investigated the association of Apo E4 and ACE Ins/Del genotypes with stroke risk and changes in serum lipids in 228 consecutive Tunisian stroke patients, and 323 age-and gender-matched controls. Comparable frequencies of ACE Ins/Del alleles were seen between patients and controls. The prevalence of Apo ε3 allele and Apo E3/E3 were lower (P < 0.001), while the frequency of Apo ε4 allele and ε4-containing genotypes (E3/E4 and E4/E4) were elevated (P < 0.001) among patients. Higher proportion of Apo E4-carrying + ACE Del/Del positive cases were seen in young (<50 years) patients (P = 0.012), and was associated with large vessel stroke (P = 0.035). Mean serum cholesterol, LDL, HDL, and triglycerides were comparable between E4-containing and no E4-containing and ACE Del/Del-positive patients. Apo E4 and ACE Del/Del genotype combination substantially increase stroke risk, supporting the notion that interactions of multiple gene variants influence stroke pathogenesis.     

The plasminogen activator inhibitor (PAI)-1 promoter 4G/4G genotype is not associated with ischemic stroke in a population of German children. Childhood Stroke Study Group

OBJECTIVES: To investigate the relationship between an insertion/deletion (4G/5G) polymorphism of the plasminogen activator inhibitor (PAI)-1 gene and childhood patients with a past history of ischemic stroke. METHODS: The PAI-1 4G/4G genotype and the coinheritance with lipoprotein (Lp) (a) levels, the factor V (FV) G1691A mutation, the prothrombin (PT) G20210A variant, and the methylene-tetrahydrofolate reductase (MTHFR) T677T genotype were studied in 198 Caucasian children with stroke and 951 controls (same age, sex and ethnical distribution). In a randomly selected subgroup of patients/controls (n=60) PAI-I activities have been investigated. RESULTS: The distribution of the 4G/5G genotypes was no different in childhood stroke patients and controls, with a 4G allele frequency of 55.8% in patients compared with 53.8% in control subjects (P=0.49). The 4G/4G genotype compared with the remaining genotypes was present in 43 cases and 167 (17.6% vs. 21.7%; OR/CI: 1.30/0.89-1.98; P=0.3). PAI-1 activity was significantly elevated (P < 0.001) in the patient group. CONCLUSIONS: Data presented here suggest that the 4G/4G genotype is not a major risk factor in the aetiology of childhood ischemic stroke.     

One-tube method for complete HPA-1 genotyping by PCR using sequence-specific primers

Human platelet antigens (HPA) can be targets for antibody responses that cause life-threatening thrombocytopenia following platelet transfusions or pregnancy. As an aid to diagnosis and prevention, serologic and DNA-based methods have been developed to type HPA. Of the DNA-based strategies, those using the polymerase chain reaction (PCR) are very sensitive, but often require processing of amplification products. Sequence-specific primers (SSP) in the PCR eliminate the need for extensive handling of reaction products beyond gel electrophoresis. However, current methods require a separate reaction for each allele being typed. In this report we describe a method to simultaneously and completely genotype both alleles of HPA-1 in a single PCR. In addition, because the absence of an amplification product might also show the failure of a SSP, we introduced a recombinant template that can only be amplified by the SSP, thus ensuring primer performance and the identified genotype.     

MICB 0106等位基因与湖北汉族人溃疡性结肠炎的相关性

目的 MHC Ⅰ类相关基因(MHC class Ⅰ chain-related gene,MIC)与MHC Ⅰ类基因连锁,同源性很高.我们的前期研究发现MICA和MICB微卫星多态性与溃疡性结肠炎(UC)相关,本研究继续探讨MICB第2、3、4外显子基因多态性与UC的相关性,以期发现UC的易感基因.方法 采用聚合酶链反应-单链构象多态性方法(PCR-SSCP),对105例湖北汉族UC患者和213例正常对照者进行MICB基因分型.结果 UC患者的MICB 0106等位基因频率较正常组显著增高(19.0%比8.9%,P=0.000,Pc＜0.001,OR=2.402,95%CI为1.488～3.879).在临床亚型分析中,MICB 0106等位基因频率在全结肠炎、中重度UC组及有肠外表现的UC患者中均显著增高(分别为24.4%比8.9%,P=0.000,Pc＜0.001,OR=3.294,95%CI为1.800～6.027;24.1%比8.9%,P=0.000,Pc＜0.001,OR=3.249,95%CI为1.893～5.576;20.5%比8.9%,P=0.002,Pc=0.012,OR=2.626,95%CI为1.418～4.861).而且MICB 0106等位基因频率在男性和年龄≥40岁的患者中比正常组显著增高(分别为22.1%比8.0%,P=0.001,Pc=0.006,OR=3.276,95%CI为1.737～6.178;28.8%比8.3%,P=0.000,Pc＜0.001,OR=4.500,95%CI为2.381～8.504).结论 MICB 0106等位基因与湖北汉族人UC存在显著相关性,而且与全结肠炎、中重度UC、肠外表现、男性及年龄≥40岁的患者有关,提示携带MICB 0106等位基因的个体对UC存在遗传易感性.     

白细胞介素-1F7基因单核苷酸多态性对强直性脊柱炎易感性与病情的影响

目的 探讨白细胞介素(IL)-1F7基因rs3811047位点单核苷酸多态性(SNP)对强直性脊柱炎(AS)易感性和临床表现型的影响.方法 收集AS患者158例和同期健康献血人群181名,采用连接酶检测反应(LDR-PCR)方法检测IL-1F7基因rs3811047位点SNP,分析其等位基因频率及基因型频率在AS和对照组中的分布,并比较不同基因型AS患者间临床表现型的差别.结果 AS患者和对照人群中rs3811047位点A等位基因频率(12.03%,17.68%)和G等位基因频率(87.97%,82.32%)的分布差异有统计学意义(x2=4.2204,P=0.0399);AA,AG,GG基因型频率在AS中分别为0,24.05%,75.95%,与对照组分布(2.76%,29.83%,67.41%)相比,差异亦有统计学意义(x2=6.2675,P=0.043).AG基因型的AS患者中人类白细胞抗原(HLA)-B27阳性率为70.27%(26/37),明显低于GG基因型AS中HLA-B27的阳性率94.23%(98/104),差异有统计学意义(x2=2.168,P=0.030);其红细胞沉降率和C反应蛋白水平明显亦低于GG基因型组(t=2.971,P=0.013;t=3.300,P=0.001).结论 安徽籍汉族人群AS易感性与IL-1F7基因rs3811047位点SNP有关,其基因型对AS的临床表现型有影响,携带A等位基因患者的炎症表现轻于不携带A等位基因的患者.     

MMP-2C735T、MMP-9C1562T基因多态性与缺血性卒中患者的卒中及其亚型大动脉粥样硬化性卒中有关，但与转归无关

目的 探讨基质金属蛋白酶（matrix metallop roteinase,MMP）-2C735T和MMP-9C1562T基因多态性与缺血性卒中患者的TOAST分型和转归的关系。方法232例缺血性卒中患者根据TOAST标准分被为大动脉粥样硬化性卒中（large arery atherosclerosis,LAA）(n...     

Human platelet alloantigens (HPA) 1, HPA2, HPA3, HPA4, and HPA5 polymorphisms in sickle cell anemia patients with vaso‐occlusive crisis

Objectives: Vaso‐occlusive crisis (VOC) is a significant cause of morbidity and mortality in sickle cell anemia (SCA) patients. Insofar as polymorphism in human platelet alloantigen (HPA) exhibit a prothrombotic nature, we hypothesized that specific HPA polymorphic variants are associated with VOC. We investigated the distribution of HPA1, HPA2, HPA3, HPA4, and HPA5 alleles genotypes among VOC and non‐VOC control SCA patients. Patients/methods: This was a case–control study. Study subjects comprised SCA patients with (VOC group; n = 127) or without (Steady‐state group; n = 130) VOC events. HPA genotyping was done by PCR‐SSP. Results: Significantly higher frequencies of HPA‐2b, HPA‐3b, and HPA‐5b alleles, and marked enrichment of HPA‐3b/3b, HPA‐5a/5b, and HPA‐5b/5b genotypes, were seen in VOC than in control SCA patients. Taking homozygous wild‐type genotypes as reference, univariate analysis identified HPA‐3a/3b, HPA‐3b/3b, and HPA‐5b/5b to be associated with VOC. Multivariate analysis confirmed the independent association of only HPA‐3a/3b and HPA‐3b/3b genotypes with VOC. HPA‐3 genotypes were significantly correlated with VOC frequency, type, and medication, and requirement for hospitalization. While both HPA 3a/3b (P = 0.002; OR = 2.94; 95% CI = 1.49–5.77) and 3b/3b (P = 0.006; OR = 3.16; 95% CI = 1.40–7.17) genotypes were associated with need for hospitalization, only HPA‐3b/3b was associated with VOC frequency, type (localized vs. generalized), and medication (narcotics vs. NSAIDs). Conclusion: This confirms the association of HPA polymorphisms with SCA VOC, of which HPA‐3 appears to be independent genetic risk factors for SCA VOC.     

NOD2/CARD15 gene polymorphisms in Crohn's disease: a genotype- phenotype analysis

OBJECTIVES: Three recently identified NOD2/CARD15 mutations have been described associated with an increased susceptibility Crohn's disease (CD). Our aim was to examine the potential association of these NOD2 mutations with CD and different subsets of CD phenotypes in our population. METHODS: Two hundred and five well-defined CD patients from north-western France and 95 ethnically matched healthy controls were genotyped for mutations R702W, G908R and Leu1007insC by DNA sequencing. Allele and genotype frequencies of NOD2 variants were examined in the whole series of CD and in different subgroups of CD phenotypes defined by the clinical characteristics of the Vienna classification (age at diagnosis, location and behaviour) or by histological features (granuloma). RESULTS: Carriers of at least one NOD2/CARD15 variant were significantly more frequent in CD than in controls (38.0% versus 20.0%, P < 0.002), and the R702W allele was the most significant contributor to this NOD2 association with CD. Homozygotes and compound heterozygotes combined had a higher risk of CD (odds ratio = 12.0, P < 0.0026) than simple heterozygotes for any variant (odds ratio = 2.2, P < 0.013) compared with subjects with no variant. Univariate analysis revealed that carriage of at least one NOD2 mutation was significantly associated with ileal involvement (P < 0.03), and stricturing evolution (P < 0.0015). Granuloma was associated with an excess of the R702W allele (16.1% versus 8.0%, Pc < 0.035), and was correlated with a young age at diagnosis, whatever the NOD2/CARD15 genotype. Multivariate analysis demonstrated that carriage of NOD2/CARD15 mutants, especially R702W, was primarily and independently associated both with stricturing evolution of CD and the presence of granuloma. CONCLUSIONS: In our population, all NOD2/CARD15 mutant genotypes, especially compound heterozygosity, were found to increase the risk of CD, but R702W was the sole allele showing a significant association with CD. In addition, we confirm the positive and independent association of the R702W mutation with stricturing behaviour and describe a second one with the presence of granuloma.     

Gene frequencies of human platelet alloantigens in Bahraini Arabs

Human platelet antigens (HPA) are implicated in the pathophysiology of certain hematological disorders, and as varied distribution of HPA-1 alleles and genotypes were reported fordifferent countries and ethnic populations, we determined the distribution of HPA-1, -2, -3, -4, and -5 alleles, genotypes and haplotypes for 194 healthy Bahraini subjects by polymerase chain reaction with sequence specific primers. The distribution of the HPA polymorphisms was in Hardy-Weinberg equilibrium. Allele frequencies of 0.76 and 0.24 (HPA-1a and -1b), 0.77 and 0.23 (HPA-2a and -2b), 0.57 and 0.43 (HPA-3a and -3b), 0.93 and 0.07 (HPA-4a and -4b), and 0.86 and 0.13 (HPA-5a and -5b) were seen. With the exception of HPA-3a/a (30.4%), the frequencies of homozygous HPA-1a/a (56.8%), 2a/a (60.1%), 4a/a (87.2%), and 5a/a (75.7%) were higher than those of heterozygous (a/b) or homozygous (b/b) variants. Our results provide basic information for further studies of the HPA system polymorphism, which in turn will be instrumental in understanding and treating immune-mediated platelet disorders.     

Rheumatoid arthritis association with the FCRL3 -169C polymorphism is restricted to PTPN22 1858T-homozygous individuals in a Canadian population

OBJECTIVE: Variants in genes encoding the Fc receptor-like 3 (FcRL-3) and the class II major histocompatibility complex (MHC) transactivator proteins have been associated with an increased risk of rheumatoid arthritis (RA) in Japanese and Nordic populations, respectively. The aim of this study was to investigate these associations in a Canadian Caucasian cohort of RA cases and healthy controls. METHODS: A total of 1,187 RA patients and 462 healthy controls were genotyped for FCRL3 and MHC2TA gene variants associated with RA. Epistasis between the FCRL3 -169C and the PTPN22 1858T variants was also examined. RESULTS: An association was detected between RA and both the FCRL3 -169C allele (OR 1.19, P = 0.023) and the homozygous genotype (OR 1.41, P = 0.027), but association of the MHC2TA promoter region variant (-168G) with RA was not replicated. Stratification of the RA cohort by PTPN22 genotypes revealed the FCRL3 risk variant and RA association was stronger in the patient subgroup lacking PTPN22 1858T variants (P = 0.004) and was not detectable in the subgroup with PTPN22 1858T variants (P = 0.52). The PTPN22 association with RA was greater in the absence than in the presence of the FCRL3 -169C allele (P = 0.0008 versus P = 0.001). The PTPN22 1858T variant also increased the risk of autoimmune thyroid disease (AITD) in the RA patients, whereas the FCRL3 risk variant was protective against AITD. CONCLUSION: Our findings support an association of RA with an FCRL3 functional polymorphism and reveal that this association is stronger in the absence of PTPN22 risk genotypes. These findings support a genetic heterogeneity across RA populations, suggesting that both the FCRL3 and PTPN22 genes play roles in RA susceptibility, but in different individuals.     

DNA sequencing-based typing of HPA-1 to HPA-17w systems

Although several DNA-based human platelet antigens (HPA) typing techniques, such as PCR-SSP and PCR-SSO, have been established, the typing errors and the lack of interlaboratory reproducibility are still the issues of concerns. In the present study, polymerase chain reaction primers were designed for identification of all the phenotypically different HPA-1 to HPA-17w types by sequencing-based typing (SBT) method using genomic DNA samples. No discrepancies were observed between PCR-SSP typing and SBT typing in typing a panel of HPA-typed platelet donors that included all common HPA types and the rare HPA-1b, 2b, 3b, and 6bw homozygous donors.     

Cytotoxic T lymphocyte-associated molecule-4 polymorphism and relapse of Graves' hyperthyroidism after antithyroid withdrawal

We studied the A/G single nucleotide polymorphism (SNP) at position 49 in exon 1 of the cytotoxic T lymphocyte-associated molecule-4 gene in 148 Chinese Graves' disease (GD) patients and 171 controls. Our primary aim was to test for the association of this SNP with the relapse of the hyperthyroidism after antithyroid withdrawal. Our secondary aim was to investigate the relationship between GD patients and controls according to the SNP genotypes. All GD patients were divided into the following three groups according to the time of relapse after drug discontinuation: group 1, early relapse within 9 months; group 2, relapse between 10 and 36 months; and group 3, relapse 3 or more years after discontinuation of treatment. There was a significant difference of genotype frequencies (P < 0.001) and allele frequencies (P < 0.001) among the three groups of patients. The frequency of the G/G genotype decreased from 79% to 64% and 39% in groups 1, 2, and 3, respectively. Compared with controls, a strong association (P < 0.001) of G allele was found for group 1, and moderate significance (P = 0.04) was found for group 2, but no association (P = 0.33) was found for group 3. At the end of treatment, the percentage of patients with persistent TSH-receptor antibody was statistically different (A/A, 9.0%; A/G, 20.8%; G/G, 45.5%; P = 0.004). Using 3 yr as the cutoff point for multivariate logistic regression analysis, we found that the G/G genotype (adjusted odds ratio, 3.1 compared with A/G plus A/A; 95% confidence interval, 1.3-7.1), larger goiter size at the end of treatment, and positive TSH-receptor antibody at the end of treatment were independent risk factors of recurrence. We conclude that the A/G polymorphism of the cytotoxic T lymphocyte-associated molecule-4 gene affects the progress of GD. The G/G genotype is associated with poor outcome.     

Human platelet antigen 1, 2 and 5 gene polymorphisms in Egyptians and their potential association with susceptibility to immune thrombocytopenic purpura in Egyptian patients

Objectives: This study determined the incidence of HPA1, HPA2 and HPA5 polymorphisms in 120 Egyptian immune thrombocytopenic purpura (ITP) patients and 120 healthy Egyptian subjects.

Methods: Human platelet antigen (HPA) genotyping was done using the polymerase chain reaction-restriction fragment length polymorphism.

Results: The frequency of HPA1 allele a and b was 78.75 and 21.25% in controls, 80.8 and 19.2% in ITP, respectively. HPA2 allele a and b frequency was 86.25 and 13.75% in controls and of 74.6 and 25.4% in patients, respectively. HPA5 allele a and b frequency was 87.5 and 12.5% in controls, in patients it was 85 and 15%, respectively. With the exception of HPA2, no other significant difference was encountered in HPA allele frequency between controls and ITP patients.

Discussion: Egyptian HPA profile is closely linked to Middle East and neighboring Arabs. The current study noted that in all the studied HPA systems 1, 2 and 5, the ‘a’ allele is more prevalent than the b allele; the most frequent genotype was the homozygous a/a genotype. HPA2b frequency, homo- and hetero-zygous HPA2b genotype frequencies were significantly higher in ITP patients compared to controls.

Conclusion: HPA 2b are 2.37 times more likely to develop ITP compared to those without this allele. The relatively high allele frequency of the HPA-1b in the Egyptian population suggests that this ethnic group has a higher risk of alloimmunization.     

Investigation of the interleukin 1 gene cluster and its association with acute pancreatitis

The interleukin 1 (IL-1) gene cluster has been implicated in acute pancreatitis. Penta-allelic and bi-allelic polymorphisms exist in the IL-1RN and IL-1B genes, respectively. The aim of the study was to investigate these polymorphisms in acute pancreatitis. Genotype and allele frequencies were determined in patients (n = 116) and healthy controls (n = 170) using the polymerase chain reaction. PCR products from the IL-1B study were further digested with Taq I restriction endonuclease. Patients were categorised according to aetiology, severity, and organ-failure scores. Allele 1 of the IL-1RN polymorphism was significantly increased in patients compared with controls (72.0 vs. 63.0%; p = 0.029, Pc = 0.029), in severe cases compared with controls (81.9 vs. 63.0%; p = 0.002, Pc = 0.004), in idiopathics compared with controls (82.4 vs. 63.0%; p = 0.002, Pc = 0.006), and in severe cases compared with mild cases (81.9 vs. 67.5%; p = 0.023, Pc = 0.046). Allele 2 was significantly decreased in severe cases compared with controls (18.1 vs. 33.0%; p = 0.013, Pc = 0.026), in idiopathics compared with controls (17.6 vs. 33%; p = 0.013, Pc = 0.039), and in severe cases compared with mild cases (18.1 vs. 32.5%; p = 0.023, Pc = 0.046). No significant differences were found for the Taq I allele or genotype frequencies between controls and patients/subgroups of patients. IL-1RN appears to determine severity of acute pancreatitis and susceptibility to idiopathic acute pancreatitis. No association was found between IL-1B and the disease.