红花对肝星状细胞基质分解素-1及其抑制因子基因表达的调节

目的 观察红花对HSC-T6细胞基质分解素-1(MMP3)及其抑制因子基因表达的影响.方法 以不同浓度的红花(1.0、0.5 g/L)作用于培养的肝星状细胞株HSC-T6细胞48 h,收集细胞,提取总RNA;用逆转录-聚合酶链反应(RT-PCR)方法测定MMP3及金属蛋白酶组织抑制因子-1(TIMP-1)的基因表达水平.结果 MMP3基因表达水平在红花1.0、0.5 g/L两组分别为2.80±0.36、2.52±0.32,而空白对照组为2.13 ±0.30.TIMP-1基因表达水平在红花1.0、0.5 g/L两组分别为1.66±0.23、2.04±0.30,而空白对照组为4.03±0.56.结论 红花可增强HSC-T6细胞MMP3的基因表达,并显著抑制HSC-T6细胞TIMP-1的基因表达,且与剂量有关.     

表皮生长因子对肝星状细胞c-jun基因表达的影响

目的 观察表皮生长因子(EGF)对肝星状细胞c-jun基因表达的影响.方法 在培养的肝星状细胞株中加入不同浓度的EGF(终质量浓度20、100、500μg/L),于8、24、48、72 h四个时间点分别收集细胞,提取肝星状细胞总RNA;用逆转录定量聚合酶链反应(PCR)方法测定c-jun的基因表达水平.结果 EGF 3组HSC-T6细胞c-jun基因表达水平在8 h(1.46±0.16、2.12±0.20、2.78±0.32)、24 h(1.32±0.13、1.87±0.17、2.43±0.26)、48 h(1.03±0.10、1.51±0.13、2.03±0.20)、72 h(0.77±0.09、1.17±0.10、1.66±0.12)四个时间点均显著高于对照组;随剂量加大,HSC-T细胞c-jun基因表达水平逐渐升高;3组间差异有统计学意义.结论 EGF对肝星状细胞c-jun基因表达有明显的上调作用.     

熊果酸对肝癌细胞株Bel-7404转移及侵袭能力的影响

目的 观察熊果酸(UA)对肝癌细胞株Bel-7404细胞转移侵袭能力及相关基因基质金属蛋白酶(MMP)-2、金属蛋白酶组织抑制因子(TIMP)-2 mRNA和蛋白表达水平的影响.方法 选用3个组:A组(UA 50 μmol/L)、B组(顺铂10mg/L)和C组(DMEM空白对照)对Bel-7404细胞进行处理,用细胞迁移实验及Transwell小室法检测细胞的迁移及侵袭能力,逆转录-聚合酶链反应(RT-PCR)及Western blot法检测细胞中MMP-2、TIMP-2 mRNA及蛋白的表达水平.结果 对Bel-7404细胞作用48 h后,A、B两组细胞的迁移速率(35.2±8.7)、(30.5±8.6)μm/h及侵袭穿膜细胞数(21.2±5.3)、(20.2±5.7)个、MMP-2 mRNA 0.24±0.06、0.23±0.05及蛋白0.21±0.01、0.24±0.04表达水平均较C组(75.6±8.7)μm/h、(54.8±7.8)个、0.46±0.11、0.42±0.06明显降低,差异均有统计学意义(P<0.01),而TIMP-2 mRNA0.87±0.05、0.83±0.06及蛋白0.98±0.06、0.95±0.09表达水平均比C组0.31±0.02、0.59±0.02高,差异均有统计学意义(P<0.01);A、B两组间细胞的迁移速率、侵袭穿膜细胞数、MMP-2和TIMP-2 mRNA及蛋白表达水平的比较差异均无统计学意义(P>0.05).结论 UA可抑制肝癌Bel-7404细胞株的迁移侵袭,其机制可能与MMP-2表达下调而TIMP-2表达上调有关.UA 50 μmol/L对Bel-7404细胞迁移侵袭能力的抑制作用与顺铂10 mg/L具有相同的效果及机制.     

腺相关病毒和慢病毒作为小干扰RNA转运载体的比较

目的 观察以腺相关病毒(adeno-associated virus,AAV)和慢病毒(Lenti virus)为载体、含有针对大鼠金属蛋白酶组织抑制因子(tissue inhibitor of metalloproteinase,TIMP)-1、具有较强抑制作用的小干扰RNA(small interfering RNA,siRNA)感染大鼠肝星状细胞系(hepatic stellate cell,HSC)-T6的感染效率和其对TIMP-1的表达抑制作用.方法 挑选针对大鼠TIMP-1基因具有较强抑制作用的siRNA序列,在体外构建为短发夹表达载体后,将其包装为重组AAV/siRNA-TIMP-1/GFP和Lenti/siRNA-TIMP-1/GFP,同时包装阴性对照AAV/GFP和Lenti/GFP,并以MOI=10感染大鼠肝星状细胞系HSC-T6,感染后72 h,通过流式细胞仪及荧光显微镜观察病毒的感染效率.在感染后7 d,应用Western bloting方法检测TIMP-1蛋白表达情况.结果 感染HSC-T6后细胞形态、增生速度未发生明显变化.通过流式细胞仪及荧光显微镜证实感染效率分别为:空载体AAV/GFP和Lenti/GFP组分别为72.7%和70.0%,AAV/siRNA.TIMP-1/GFP和Lenti/siRNA-TIMP-1/GFP感染组分别为64.58%和61.86%.与正常细胞相比,感染后7 d,siRNA感染组TIMP-1蛋白表达均下降约40.0%,但两组siRNA感染组下降幅度无统计学意义.结论 构建的重组AAV/siRNA-TIMP-1/GFP和Lenti/siRNA.TIMP-1/GFP均可有效感染大鼠HSC-T6,感染效率相近,且均可在短期内有效抑制大鼠肝星状细胞系HSC-T6 TIMP-1蛋白的表达.     

生长因子对大鼠肝星状细胞间质胶原酶基因表达的调节作用

目的 了解转化生长因子—β(TGF—β)、表皮生长因子(EGF)、血小板衍生生长因子(PDGF)对大鼠肝星状细胞间质胶原酶(MMP13)基因表达的影响。方法 在培养的肝星状细胞系中加入TGF—β(1μg／L)、EGF(100μg／L)和PDGF(200μg／L)，于不同的时间点(8、24、48、72h)收集细胞，提取总RNA；用逆转录定量多聚酶链反应(PCR)方法测定MMP13的基因表达水平。结果 TGF-β组肝星状细胞MMP13基因表达水平在8、24、48、72h4个时间点均明显低于对照组。EGF组肝星状细胞MMP13的基因表达水平在8、24、48h均明显高于对照组；24h达高峰，为对照组的3倍。PDGF组肝星状细胞MMP13的基因表达水平在8、24、48、72h均明显高于对照组；48h达高峰，为对照组的3倍。结论 TGF—β可抑制大鼠肝星状细胞MMP13基因的表达；而EGF、PDGF可增强肝星状细胞MMP13基因的表达。     

细菌脂多糖对人肝细胞过氧化物酶体增殖物受体γ共激活因子1a、线粒体融合蛋白2基因表达的调节及对线粒体形态和功能的影响

目的 观察细菌脂多糖(LPS)对肝细胞株LO2细胞过氧化物酶体增殖物受体γ共激活因子1a(PGC-1a)、线粒体融合蛋白2(Mfn2)基因表达的调节作用以及对线粒体形态和细胞三磷酸腺苷(ATP)、活性氧(ROS)生成的影响.方法 分别以LPS(10 μg/L)、LPS(10μg/L)+罗格列酮(10 μmol/L)、LPS( 10 μg/L)+GW9662( 10 μmol/L)作用LO2细胞株12h,实时定量-聚合酶链反应(Real-time PCR)和Western blot法检测各组细胞PGC -1a、Mfn2 mRNA转录及蛋白表达水平,透射电镜观察线粒体形态变化,荧光素酶二磷酸腺苷( ADP)/ATP发光检测细胞ATP含量,荧光探针2',7'-二氯荧光素乙二酯(DCFH-DA)测定细胞ROS生成水平.结果 经LPS处理LO2细胞后PGC-1a、Mfn2基因的mRNA及蛋白表达水平显著低于空白对照组,差异有统计学意义(1.2314±0.0366比2.5896 ±0.2591；0.7432 ±0.1626比1.6236±0.3058,P＜0.05)；细胞线粒体数量减少、肿胀明显、嵴模糊不清、基质密度低、少数线粒体膜不完整；细胞内ATP浓度显著低于对照组(2.50 ±0.15比5.81 ±0.31,P＜0.05)；而ROS生成水平较对照组明显升高(150.1920±6.3571比55.1920±9.1140,P＜0.05).罗格列酮可通过提高PGC-1a、Mfn2基因表达逆转这一改变；而GW9662抑制PGC-1 a、Mfn2基因表达,进一步加重线粒体损伤.结论 LPS通过抑制肝细胞PGC-1a、Mfn2基因表达诱导线粒体形态改变及功能障碍.     

大鼠肝星状细胞TGF-β3/TGF-β1mRNA比值与TGF-β1、MMP-9、TIMP-1表达的关系

目的 探讨大鼠肝星状细胞(HSC-T6)中转化生长因子-β3(TGF-β3)和转化生长因子-β1(TGF-β1)mRNA比值变化与TGF-β1、MMP-9、TIMP-1表达的关系.方法 构建质粒pcDNA 3.1(+)-TGF-β3和pcDNA 3.1(+)-TGF-β1.将pcDNA 3.1(+)-TGF-1β1转染HSC-T6细胞株,经筛选建立高表达TGF-β1的HSC-T6细胞阳性克隆.pcDNA 3.1(+)-TGF-β3转染该阳性克隆,48 h后荧光定量PCR法和Western blot法分别检测TGF-β3、TGF-β1、MMP-9和TIMP-1 mRNA和蛋白的变化.结果 空白组、对照组、阳性克隆组及TGF-β3干预组中,TGF-β3/TGF-β1mRNA比值分别为0.286±0.070、0.874±0.141、0.448±0.327和1.277±0.244;阳性克隆组与空白组和对照组相比,TGF-β1和TIMP-1的mRNA及蛋白表达明显增高(P<0.05),MMP-9的mRNA及蛋白表达明显减少(P<0.05);TGF-β3干预组与阳性克隆组相比,TGF-β1蛋白和TIMP-1 mRNA及蛋白表达明显下降(P<0.05),MMP-9 mRNA及蛋白表达明显增加(P<0.05).结论 TGF-β3能下调TGF-β1蛋白表达;当TGF-β3/TGF-β1mRNA比值>1时,TGF-β1和TIMP-1表达减少,MMP-9表达增加;当TGF-β3/TGF-β1mRNA比值<1时,TGF-β1表达减少,TIMP-1和MMP-9表达无变化.     

绝经后妇女基质金属蛋白酶3和抑制因子水平及其与骨密度和骨桥蛋白的关系

目的探讨绝经后妇女血清基质金属蛋白酶-3(MMP-3)和抑制因子(TIMP-1)水平及其与骨密度和骨桥蛋白的关系。方法将102名绝经后妇女用酶联免疫吸附试验(ELISA)测定的血清MMP-3、TIMP-1和骨桥蛋白(OPN)水平,计算MMP-3/TIMP-1比值,用双能X线吸收法(DEXA)测定腰椎正位,股骨颈,Ward’s区和大粗隆的骨密度(BMD)。结果①骨质疏松组中MMP-3的数值(154±111)ng/ml高于正常组(124±103)ng/ml,而TIMP-1的数值(134±116)μg/L低于正常组(146±130)μg/L,血清OPN数值(57±19)ng/ml明显高于正常组(26±10)ng/ml。②骨质疏松组中MMP-3与MMP-3/TIMP-1比值和血清OPN存在明显正相关性(P<0.05),MMP-3/TIMP-1比值与骨密度存在明显负相关性(P<0.05),TIMP-1和Ward’s区骨密度存在明显正相关性(P<0.05),和血清OPN存在明显负相关性(P<0.05),校正年龄和体重指数后,以上数据相关性增高(P<0.05)。结论绝经后骨质疏松症妇女MMP-3/TIMP-1比值与骨密度和OPN具有关联性,MMP-3/TIMP-1比值升高可能为绝经后骨质疏松症伴随骨代谢转换过程增快的表现。     

血管紧张素Ⅱ受体拮抗影响肝纤维化的实验研究

目的 观察血管紧张素Ⅱ及其受体拮抗剂对体外培养的肝星状细胞合成转化生长因子-β1(TGF-β1),以及金属蛋白酶组织抑制因子-1(TIMP-1)mRNA表达的影响. 方法 采用HSC-T6肝星状细胞系作为活化的肝星状细胞的研究模型.将培养的肝星状细胞随机分为对照组、血管紧张素Ⅱ(AngⅡ)组、受体拮抗剂(AT1RA)组和血管紧张素Ⅱ+受体拮抗剂(AngⅡ+AT1RA)组.采用ELISA法检测细胞培养上清液中TGF-β1蛋白的含量.RT-PCR法检测肝星状细胞中TIMP-1 mRNA的表达. 结果 细胞培养上清液中TGF-β1蛋白的含量,对照组、AngⅡ组和AngⅡ+AT1RA组分别为(7.531±0.654)pg/mL、(9.855±1.485)pg/mL和(7.719±0.329)pg/mL,AngⅡ组高于对照组(P＜0.05),AngⅡ+AT1RA组显著低于AngⅡ组(P＜0.05).肝星状细胞TIMP-1mRNA的表达水平,对照组、AngⅡ组和AngⅡ+AT1RA组分别为3.387±0.042、4.870±0.061和3.837±0.042,AngⅡ组高于对照组(P＜0.05),AngⅡAT1RA组显著低于AngⅡ组(P＜0.05). 结论 血管紧张素Ⅱ能够促进肝星状细胞TGF-β1蛋白的合成以及TIMP-1 mRNA的表达,而血管紧张素Ⅱ1型受体拮抗剂能够明显抑制这一作用.     

自体血管内皮祖细胞移植治疗高肺血流量肺动脉高压

目的 观察自体血管内皮祖细胞(EPCs)移植对高肺血流肺动脉高压(PAH)的治疗作用.方法 将30头实验幼猪随机分为3组,每组10头.假手术组(Sham组)仅开胸;对照组(Control组)行左胸后外侧切口,降主动脉与主肺动脉分流术;EPCs治疗组(EPCs组)手术操作同对照组,术后2周给予EPCs 2×10 7个细胞,颈静脉输入.术前与术后30 d,观察3组猪的肺动脉收缩压(PASP)、肺血管阻力(PVR),血清基质金属蛋白酶(MMP)-9、内皮素-1(ET-1)、白细胞介素(IL)-6、IL-8水平变化,以及肺组织p38丝裂原激活蛋白激酶(p38 MAPK)表达活性,肺动脉标本的组织学变化.结果 术后30 d,与Sham组比较,PASP、PVR、MMP-9、ET-1、IL-6、IL-8、p38MAPK在Control组[(6.63±1.20) kPa、(10.44 ±2.53) wood's U、(76.63±10.39) μg/L、(103.66±17.31) μg/L、(43.00 ±7.33) ng/L、(67.39±9.65) ng/L、3.63 ±0.33]和EPCs组[(4.07 ±0.77) kPa、(6.27±0.65) wood's U、(64.11 ±9.73) μg/L、(90.44±13.11) μg/L、(30.44±8.17) ng/L、(53.23±7.37) ng/L、1.73 ±0.37]明显升高(P＜0.01);EPCs组明显低于Control组(P＜0.05);肺组织病理学改变,Control组最为明显,EPCs组轻度改变,Sham组未见明显病理改变.结论 EPCs移植对高肺血流肺动脉高压具有治疗作用,其机制可能为抑制MMP-9、ET-1等致肺组织重构因素的水平,以及抑制肺动脉高压过程中的炎症损伤而发挥作用.     

Deficiency of TBL1XR1 causes asthenozoospermia

Transducin (β)-like 1 X-linked receptor 1 (TBL1XR1) is an evolutionarily conserved protein related to spermatozoa. To clarify its role and mechanism of action in spermatozoa, qRT-PCR was used to analyse the expression of TBL1XR1 in human spermatozoa and mouse testes. The mice were established as an animal model by injecting the mice testes with small interfering RNA against TBL1XR1 or control siRNA. Our results indicated that deficiency of TBL1XR1 in mice reduced the motility of spermatozoa and disrupted the histone-to-protamine transition. We also found the decreased expression of TBL1XR1 in the spermatozoa of human patients with asthenozoospermia (AZ) compared with that in the spermatozoa of healthy males. Moreover, we carried out chromatin immunoprecipitation analyses and found that genes downstream of TBL1XR1 were related to sperm motility. Thus, TBL1XR1 might be related to sperm motility and might function through its downstream genes. Our data highlight the role of TBL1XR1 involved in spermatozoa and provide new molecular insights into the intricate systems required for male fertility.     

Alpha1-antitrypsin deficiency. 1: epidemiology of alpha1-antitrypsin deficiency

The protein and molecular characteristics of variants of the alpha1-antitrypsin (AAT) gene are described, and available data on the genetic epidemiology of AAT deficiency are presented.     

Genetic polymorphisms of CYP1A1, CYP2E1, GSTM1, and GSTT1 associated with head and neck cancer

BACKGROUND: Alcohol intake and tobacco smoke, in addition to other environmental and genetic factors, have been associated with head and neck cancer. We evaluated the role of metabolic enzyme polymorphisms on the risk of head and neck cancer in a hospital-based case-control study. METHODS: CYP1A1MspI, CYP2E1PstI, GSTM1, and GSTT1polymorphisms were evaluated in 103 histologically confirmed head and neck cancer cases and 102 controls by means of polymerase chain reaction-restriction fragment length polymorphism methods. RESULTS: GSTM1null increased the risk of head and neck cancer (odds ratio [OR], 2.2; 95% confidence interval [95% CI], 1.24-3.79), oral cancer (OR, 2.8; 95% CI, 1.28-5.98), and pharyngeal cancer (OR, 2.2; 95% CI, 1.08-4.63). CYP2E1PstI polymorphism indicated a risk for oral cancer (OR, 3.6; 95% CI, 1.29-11.56). The joint effect of GSTM1 null and CYP1A1 polymorphism increased the risk of head and neck cancer (OR, 2.4; 95% CI, 1.13-5.10). CONCLUSIONS: GSTM1 null alone or associated with CYP1A1 increased the risk of head and neck cancer; the CYP2E1PstI mutated allele increased the risk for only oral cancer.     

手术创伤中腹膜组织Sp1、COL1A1和TIMP-1的表达

目的　探讨人手术创伤腹膜组织中核转录因子Sp1激活 ,COL1A1和TIMP 1表达变化与腹膜纤维化之间的关系。方法　采用凝胶电泳迁移率改变分析法 (EMSA)检测手术创伤后不同时间的腹膜组织核转录因子Sp1的表达水平 ,WesternBlot检测COL1A1和TIMP 1蛋白表达 ,Masson染色观察腹膜组织中胶原纤维的变化。结果　Sp1在手术创伤后 0 .5h被活化 ,随着手术时间延长Sp1活性逐渐增强 ,至创伤后 4h时达高峰 ,同时创伤腹膜组织中的COL1A1和TIMP 1蛋白表达水平逐渐升高 ,存在差异显著性 (P <0 .0 1)。在手术创伤期内随手术时间的延长腹膜组织中胶原纤维增加。结论　核转录因子Sp1活化导致Ⅰ型胶原合成增加 ,细胞外基质降解减少 ,从而启动腹膜纤维化进程。     

IgA肾病患者C1GALT1C1基因的体细胞突变筛查

目的 探讨IgA肾病（IgAN）患者β1,3半乳糖转移酶的分子伴侣Cosme编码基因C1GALT1C1基因体细胞突变情况。方法 27例IgA肾病患者及19例正常健康对照作为研究对象。提取研究对象外周血基因组DNA,扩增C1GALT1C1基因的编码区,采用PCR产物直接测序的方法进行突变筛查。然后,分离其中15例IgA肾病患者及7例健康男性对照的外周血B淋巴细胞,提取DNA。对C1GALT1C1基因编码区进行扩增,PCR产物进行克隆,各挑选平均8～10个克隆进行体细胞突变筛查。结果 46例个体全血基因组DNA的PCR扩增产物测序发现,2例患者及1例健康对照存在外显子T393A变异,次等位基因频率（MAF）为6．9%[SNP数据库（dbSNP）报告为9．5%]。B淋巴细胞DNA序列分析显示,在22例个体（15例IgA肾病患者,7例健康对照）送检的总共202个克隆中,未发现新的突变和多态性位点。结论 C1GALT1C1基因编码区T393A多态位点在本研究人群中为唯一发现的多态性位点,其次等位基因频率（MAF）较既往报道略低。本研究尚未发现IgA肾病患者B淋巴细胞存在体细胞突变。     

Evaluation of the influence of polymorphic variants CYP1A1 2B, CYP1B1 2, CYP3A4 1B, GSTM1 0, and GSTT1 0 in prostate cancer

Background/objectiveGenetic polymorphisms in cytochrome P-450 (CYPs) and glutathione S-transferase (GSTs) genes can influence the appearance of tumors by the formation of new enzymes with altered activities. In the present study, 5 polymorphic variants were examined in 154 patients with prostate carcinoma and in 154 controls.Materials and methodsDNA analysis was carried out through PCR-based methods. The statistical methods used were odds ratio and confidence interval (95% CI), χ², Fisher, and Mann-Whitney.ResultsThe study showed absence of association for CYP1A1*2B, CYP1B1*2, GSTM1*0, and GSTT1*0. The statistical analysis implied a positive association of variant CYP3A4*1B for prostate cancer. The combined analysis of CYP1A1*2B, CYP1B1*2, and CYP3A4*1B genotypes showed positive association. The analysis of histopathologic parameters detected statistically significant differences for Gleason score and biochemistry recurrence risk. The presence of the GSTT1*0 genotype in red meat consumers increased the risk for this disease.ConclusionSome polymorphic variants analyzed can influence the development and the progression of prostate cancer.     

Impact of CYP1A1, GSTM1, and GSTT1 polymorphisms in overall and specific prostate cancer survival

ObjectivePrognostic biomarkers that distinguish between patients with good or poor outcome can be used to guide decisions of whom to treat and how aggressively. In this sense, several groups have proposed genetic polymorphisms as potential susceptibility and prognostic biomarkers; however, their validity has not been proven. Thus, the main goal of the present work was to investigate the potential role of single and combined CYP1A1, GSTM1, and GSTT1 genotypes as modifiers of cancer survival in Chilean patients with prostate cancer.Methods and materialsA total of 260 histologically confirmed patients were recruited from a voluntary screening, and genomic DNA was obtained from their blood samples for genotyping analyses to detect the CYP1A1*2A polymorphism and GSTM1 and GSTT1 deletions. The progression of illness and mortality were estimated with a median follow-up of 8.82 years. Adjusted estimated genotype risks were evaluated by hazard ratio and 95% CI using the Cox proportional model. In addition, the Kaplan-Meier survival method and log-rank test were used to evaluate patient survival with regard to genotype.ResultsThe 9-year overall and specific survival rates were 67.6% and 36.6% in the GSTT1null group, 67.6% and 58.7% in the GSTM1non-null group, 69.0% and 51.6% in the *1A/*2A group, 63.9% and 61.5% in the *2A/*2A group vs. 76.2% and 62.3% in the GSTT1non-null group, 82.3% and 50% in the GSTM1null group, and 83.7% and 56.3% in the *1A/*1A group, respectively. The hazard ratios and the Kaplan-Meier curve results demonstrate that the GSTM1non-null, GSTT1null, and CYP1A1*2A genotypes are significantly associated with mortality. Our study has two main limitations: a relatively small sample size and a low global mortality percentage (25.4%); thus, we need to continue the follow-up to confirm these findings.ConclusionsOur results suggest that the GSTM1non-null, GSTT1null, and CYP1A1*2A genotypes may be good prognosis markers, particularly in patients with high-risk tumors.     

The HLA-DPB1--associated component of the IDDM1 and its relationship to the major loci HLA-DQB1, -DQA1, and -DRB1

The major histocompatibility complex (MHC) HLA region on chromosome 6p21 contains the major locus of type 1 diabetes (IDDM1). Common allelic variants at the class II HLA-DRB1, -DQA1, and -DQB1 loci account for the major part of IDDM1. Previous studies suggested that other MHC loci are likely to contribute to IDDM1, but determination of their relative contributions and identities is difficult because of strong linkage disequilibrium between MHC loci. One prime candidate is the polymorphic HLA-DPB1 locus, which (with the DPA1 locus) encodes the third class II antigen-presenting molecule. However, the results obtained in previous studies appear to be contradictory. Therefore, we have analyzed 408 white European families (200 from Sardinia and 208 from the U.K.) using a combination of association tests designed to directly compare the effect of DPB1 variation on the relative predisposition of DR-DQ haplotypes, taking into account linkage disequilibrium between DPB1 and the DRB1, DQA1, and DQB1 loci. In these populations, the overall contribution of DPB1 to IDDM1 is small. The main component of the DPB1 contribution to IDDM1 in these populations appears to be the protection associated with DPB1*0402 on DR4-negative haplotypes. We suggest that the HLA-DP molecule itself contributes to IDDM1.