人鼻咽癌细胞SUME逃逸NK细胞免疫杀伤机制的初步探讨

目的 探讨人鼻咽癌细胞SUME逃逸NK细胞免疫杀伤的机制.方法 以K562细胞为对照,应用乳酸脱氢酶(LDH)释放法检测不同效靶比时体外培养的同种异体自然杀伤(NK)细胞杀伤SUME细胞的活性.用RT-PCR检测K562和SUME细胞MHC-Ⅰ类链相关分子A和B(MICA/B)、人巨细胞病毒糖蛋白UL16结合蛋白(ULBP)1～3基因,用流式细胞仪检测两组细胞MICA/B、ULBP1～3和HLA-Ⅰ分子的表达情况.结果 同一效靶比时NK细胞杀伤SUME细胞的活性低于杀伤K562细胞的活性(P＜0.05);K562和SUME细胞均表达基因MICA/B和ULBP1～3,但SUME细胞低表达MICA、MICB和ULBP1～3分子.结论 SUME细胞逃逸NK细胞免疫杀伤的可能机制是SUME细胞高表达HLA-Ⅰ类分子,低表达NKG2D的配体MICA/B和ULBP1～3.     

HLA-B27启动子荧光素酶报告基因载体的构建及其在Hela细胞的转录调控研究

目的 构建荧光素酶报告基因（luc）与HLA-B27启动子融合蛋白哺乳动物细胞表达载体，观察其在Hela细胞的表达调控。方法 克隆出HLA-B27启动子序列（432bp），构建pGL4．14／B27pro-luc融合蛋白表达载体。转染Hela细胞构建稳定转染细胞系。观察不同的细胞因子对B27转录水平的表达调控。结果 首先成功构建B27启动子-luc融合蛋白表达载体：然后使用此载体转染Hela细胞构建B27启动子的稳定转染Hela细胞株。应用该细胞株，发现肿瘤坏死因子（TNF）-α、干扰素（IFN）-α、IFN-β和IFN-γ可以通过调节稳定转染的B27启动子活性显著增加B27的转录水平（P〈0．05），其启动子活性比基础表达水平分别增高（1．67±0．20）倍，（1．79±0．71）倍，（2．94±0．68）倍和（1．98±0．45）倍。结论 HLA—B27启动子活性在Hela细胞中只有可调节性。细胞因子TNF-α、IFN-α、IFN-β和IFN-γ可通过调控HLA-B27启动子的活性而调节HLA-B27的表达。     

K562细胞可溶性抗原负载树突状细胞体外诱导CTL作用的研究

目的探讨经K562细胞裂解物冲击致敏的外周血单个核细胞衍生的树突状细胞（DC）的生物特性及体外诱导抗原特异性CTL应答的能力。方法采集健康人抗凝外周血分离单个核细胞，贴壁细胞用含rhGM—CSF、rhIL-4、TNF—α的RPM1640＋10％FBS培养基体外诱导培养产生DC，5天收获细胞并将细胞分组：A组：未负载抗原DC；B组：加入K562细胞裂解液脉冲DC。7天后用流式细胞仪检测成熟DC免疫表型，并将非贴壁细胞（淋巴细胞）作为效应细胞与各组DE共育，以产生细胞毒性T淋巴细胞（CTL）。12天用LDH释放试验测定对K562细胞的杀伤活性。并用ELISA方法测定细胞上清液中IL-12的含量。结果（1）经细胞因子联合体外诱导的各组DC较培养前在数量，形态及免疫表型上差异有统计学意义，CD86、CD83、CD40、CD1a表达增加，其中经K562细胞裂解液冲击的DC的CD83CD86表达率明显升高。（2）效应细胞与K562细胞混合培养时，负载K562细胞裂解液的DC刺激后的T细胞比单独DC刺激后的T细胞对K562细胞的杀伤作用更明显。（3）负载K562细胞裂解液的DC细胞培养上清液中产生IL-12含量较未负载抗原的DC明显增加。结论用GM—CSF、IL-4以及TNF—α诱导培养健康人外周血单个核细胞可以得到成熟的DC，且经K562细胞裂解液致敏可以进一步促进DC的成熟并体外诱导特异性杀伤靶细胞的CTL。     

树突状细胞与细胞因子诱导的杀伤细胞共培养对白血病耐药细胞杀伤作用的实验研究

目的探讨负载P-糖蛋白(P-gp)高表达的多药耐药(MDR)白血病K562/A02细胞冻融抗原的树突状细胞(DC)与同源细胞因子诱导的杀伤细胞(CIK)共培养对MDRK562/A02杀伤作用的影响。方法提取健康人骨髓单个核细胞,常规诱导出DC及CIK,将K562/A02细胞冻融物作为抗原冲击的DC,与CIK共培养作为实验组,抗原不冲击的DC与CIK共培养作为对照组,以CIK及DC单独培养分别作为空白对照组1和空白对照组2。光镜下观察细胞形态,流式细胞术分析细胞表型,MTT法检测杀伤活性。结果实验组、对照组细胞增殖活性均大于CIK组(P<0.05)。实验组对K562/A02、K562的杀伤活性在效靶比5∶1、10∶1、20∶1时分别为(42.90±0.67)%、(49.85±0.28)%、(63.36±0.46)%和(23.56±0.43)%、(26.11±0.34)%、(34.46±0.35)%,均高于对照组及空白对照组1(P<0.05);实验组对K562/A02的杀伤活性高于K562和MCF7(P<0.05)。结论DC与CIK共培养物是一种增殖活性和细胞毒活性高于CIK的免疫活性细胞,而经冻融抗原冲击的DC与CIK共培养能明显提高对MDRK562/A02的杀伤活性。     

外体负载特异性抗原促进小鼠抗肿瘤效应的研究

目的:验证人树突状细胞(DC)分泌的外体(exosomes,EXO)负载NY-ESO-1抗原促进转基因小鼠特异性细胞毒性T淋巴细胞(cytotoxic T lymphocyte,CTL)扩增及增强肿瘤杀伤效应。方法:应用人类白细胞抗原(human leukocyte antigen,HLA)-A2阳性健康成人的外周血分离诱导外周血单个核细胞(peripheral blood mononuclear cells,PBMC)来源的成熟DC,利用一系列不同速度的离心结合膜超滤的方法,从其上清中提取成熟DC分泌的EXO。人工负载肿瘤睾丸抗原NY-ESO-1于EXO之上(EXO/Ag),与聚肌胞(PolyI-C)共同免疫健康HLA-A2转基因C57小鼠,并在体系中加入EXO/Ag继续体外培养脾细胞。使用以上方法获得的脾细胞行四聚体实验,并对K562细胞及黑色素瘤细胞(对照组)行杀伤实验。结果:脾细胞中NY-ESO-1特异的CTL有所扩增,对K562肿瘤细胞有一定杀伤效应。体外实验显示NY-ESO-1特异的CTL较前大量扩增,对K562肿瘤细胞杀伤效应大大增加。结论:EXO/Ag结合PolyI-C作为新一代抗肿瘤疫苗具有良好的应用前景。     

强直性脊柱炎疑似患者HLA-B27检测结果分析

对111例疑似强直性脊柱炎(AS)患者外周血T淋巴细胞HLA-B27表达进行检测,结合临床资料对AS作出诊断.共检测出HLA-B27阳性49例,总检出率为44%,结合临床资料确诊AS患者46例,包括男性HLA-B27 As患者40例、HLA-B27-AS 3例,女性HLA-B27 AS 2例、HLA-B27-AS 1例,男女患病比为4.4∶1.男性AS确诊患者的HLA-B27阳性率为88%(40/43).提示HLA-B27检测有助于疑似AS病例的确诊.     

同种异体NK细胞对CD+34早期急性髓系白血病细胞的杀伤活性

目的探讨同种异体NK细胞对CD3+4早期急性髓系白血病(AML)细胞的体外杀伤活性。方法免疫磁珠法分离5例健康个体NK细胞,以NK杀伤敏感细胞株K562作为对照,乳酸脱氢酶(LDH)释放法测定不同效靶比时NK细胞对CD3+4早期AML细胞KG1a的杀伤活性。结果AML细胞株KG1a中CD34抗原表达率为98.0%±1.1%,分选后的NK细胞纯度为93.2%±3.7%。不同效靶比时NK细胞对KG1a细胞均有杀伤活性,且随着效靶比的增高,其杀伤活性增高(P<0.05)。结论同种异体NK细胞对CD34+早期AML细胞具有一定的杀伤活性。     

人脐血和外周血树突状细胞诱导抗肝癌活性

目的　观察人脐血和外周血树突状细胞 (dendriticcells ,DC)的生物学特性及其对效应细胞体外杀伤人肝癌细胞株BEL 740 2 (B)的影响。方法　免疫组化和MTT法检测DC的生物学特性。抗肿瘤实验则分两大组 ,人外周血DC组为B +LAK +DC ,人脐血DC组为B +DC CTL ,检测效应细胞的细胞毒活性。结果　①人外周血和脐血DC均高表达HLA ABC、HLA DR、HLA DQ、CD54和S 10 0蛋白 ;刺激淋巴细胞增殖的效应均比对照组明显增高 (P <0 0 1) ,两种来源DC无显著性差异 (P >0 0 5)。②人外周血DC组和脐血DC组的细胞毒活性均为实验组 >对照组 (P <0 0 1) ,人脐血DC组 >人外周血DC组 (P <0 0 1)。结论　人外周血和脐血DC均为形态和功能成熟的DC ,均能明显增强效应细胞杀伤肝癌细胞的活性 ;而经肿瘤抗原致敏DC诱导的特异性CTL杀伤活性更强。提示临床上可根据患者的具体情况选择DC的来源     

健康老年人外周血免疫细胞功能的变化

目的 探讨健康老年人免疫细胞功能变化情况.方法 采集20例20～30岁的青年健康体检者及20例60～70岁的老年健康体检者外周血,通过PEG法检测血浆循环免疫复合物,流式细胞术检测NK、CD4+T细胞及CD8+T细胞,靶细胞K562杀伤法测定NK细胞毒.结果 老年组与青年组比,外周血循环免疫复合物水平升高;NK细胞数量无明显变化,但NK细胞毒活性明显下降;老年组CD4+T细胞与CD8+T细胞比率亦下降.结论 老年人免疫细胞功能与健康青年人比较存在一定的差异.     

肝细胞癌患者外周血NK细胞频率及受体表达

目的检测肝细胞癌(hepatocellular carcinoma,HCC)患者外周血NK细胞频率、功能及受体表达的变化,并分析其在HCC患者中表达特点。方法用流式细胞术检测36例HCC患者、34例乙型肝炎肝硬化(liver cirrhosis,LC)患者的外周血NK细胞频率及其受体CD158a、CD158b、NKG2D、NKP30、NKP44、NKP46的表达情况,用IL-12刺激外周血单个核细胞(peripheral blood mononuclear cell,PBMC)、流式细胞术检测NK细胞分泌IFN-γ、TNF-α的能力,并用流式细胞毒性分析法检测NK细胞对K562细胞的杀伤效率,对2组NK细胞频率、受体及功能进行分析和比较。结果 2组患者NK细胞的频率差异无统计学意义(P0.05)。CD56dimNK细胞的活化性受体NKG2D、NKP30表达在HCC组高于LC组(P0.05)。在IL-12刺激下HCC组CD56brightNK细胞IFN-γ、TNF-α表达率、CD56dimNK细胞IFN-γ表达率均低于LC组(P0.05)。HCC组NK细胞对K562的杀伤比例高于LC组(P0.05)。结论 HCC组NK细胞分泌细胞因子能力低于LC组,但杀伤功能强于LC组,可能与其表面活化性受体高表达有关。     

Expansion and enhanced survival of natural killer cells expressing the killer immunoglobulin-like receptor KIR3DL2 in spondylarthritis

OBJECTIVE: The spondylarthritides (SpA) are strongly associated with possession of HLA-B27. We hypothesized that the expression of abnormal forms of HLA-B27 in SpA may have a pathogenic role through interaction with cells bearing natural killer (NK) receptors, in particular, killer immunoglobulin-like receptor (KIR) KIR3DL2, a receptor for HLA-B27 homodimer (B27(2)). We therefore undertook the present study to determine the number and function of NK and T cells bearing KIR3DL2 in SpA. METHODS: Expression of KIR3DL2 on NK and T cells was quantified in peripheral blood (PB) from 35 patients with SpA and 5 patients with juvenile enthesitis-related arthritis (juvenile ERA); samples were compared with samples from healthy and rheumatoid arthritis (RA) controls. Paired synovial fluid (SF) was studied where available. Expression of other KIRs as well as activation, memory, and homing markers on KIR3DL2+ NK and T cells was quantified. NK cell survival was assessed using the apoptotic markers annexin V and 7-aminoactinomycin D, and cytotoxicity by (51)Cr release assay. RESULTS: In SpA, an increased number of PB and SF NK and CD4+ T cells expressed the KIR3DL2 receptor compared with controls. In ERA, KIR3DL2 expression was increased in PB and SF CD4 T cells (and SF NK cells) compared with RA controls. KIR3DL2+ NK cells had an activated phenotype, and were protected from apoptosis by culture with a cell line expressing B27(2). SpA PB mononuclear NK cells from SpA patients showed greater cytotoxicity than those from controls. CONCLUSION: KIR3DL2 expression on NK cells and CD4 lymphocytes is increased in SpA and ERA. These cells are activated and may have a pathogenic role.     

Effects of STI571 and p27 gene clone on proliferation and apoptosis of K562 cells

AIM: To investigate the combined effect of STI571 and p27 gene clone on the regulation of proliferation, cell cycle and apoptosis of K562 cell line. METHODS: p27 gene was obtained by RT-PCR, and its sequence was approved to be correct. Then p27-pcDNA3.1 vector was constructed and transfected into K562 cell line. p27-pcDNA3.1-K562 cell clone was screened by G418 after transfection, p27 protein was identified by Western blot. MTT was used to detect the survival rate of the cell. Flow cytometry was used to detect cell cycle and apoptosis index. RESULTS: The expression of p27 protein could be detected by Western blot in p27-pcDNA3.1-K562 cells. A strong inhibition of cell proliferation was observed in p27-pcDNA3.1 -K562 cells as compared with that of the control (pcDNA3.1 -K562 cells). The cells at G0/G1 phase were significantly increased, and cells at S phase were greatly declined. The apoptosis index was increased greatly after p27-pcDNA3.1-K562 cells were treated with STI571, and survival rate of the cell was markedly declined (0.35-0.58, P<0.05-0.048 vs STI571-K562 cell,0.35-0.72,P<0.01-0.001 vs p27-K562 cell). CONCLUSION: p27 and STI571 have a synergistic action on inhibition of proliferation and induction of apoptosis on K562 cells.     

Expansion and enhanced survival of natural killer cells expressing the killer immunoglobulin‐like receptor KIR3DL2 in spondylarthritis

Objective

The spondylarthritides (SpA) are strongly associated with possession of HLA–B27. We hypothesized that the expression of abnormal forms of HLA–B27 in SpA may have a pathogenic role through interaction with cells bearing natural killer (NK) receptors, in particular, killer immunoglobulin‐like receptor (KIR) KIR3DL2, a receptor for HLA–B27 homodimer (B27₂). We therefore undertook the present study to determine the number and function of NK and T cells bearing KIR3DL2 in SpA.

Methods

Expression of KIR3DL2 on NK and T cells was quantified in peripheral blood (PB) from 35 patients with SpA and 5 patients with juvenile enthesitis‐related arthritis (juvenile ERA); samples were compared with samples from healthy and rheumatoid arthritis (RA) controls. Paired synovial fluid (SF) was studied where available. Expression of other KIRs as well as activation, memory, and homing markers on KIR3DL2+ NK and T cells was quantified. NK cell survival was assessed using the apoptotic markers annexin V and 7‐aminoactinomycin D, and cytotoxicity by ⁵¹Cr release assay.

Results

In SpA, an increased number of PB and SF NK and CD4+ T cells expressed the KIR3DL2 receptor compared with controls. In ERA, KIR3DL2 expression was increased in PB and SF CD4 T cells (and SF NK cells) compared with RA controls. KIR3DL2+ NK cells had an activated phenotype, and were protected from apoptosis by culture with a cell line expressing B27₂. SpA PB mononuclear NK cells from SpA patients showed greater cytotoxicity than those from controls.

Conclusion

KIR3DL2 expression on NK cells and CD4 lymphocytes is increased in SpA and ERA. These cells are activated and may have a pathogenic role.

     

Expression of KIR and C-type lectin receptors in Behcet's disease

OBJECTIVE: Beh?et's disease (BD) is a multisystemic disorder with a possible underlying pathology of immune-mediated vasculitis. Genetic susceptibility associated with HLA-B*51 and B*2702 has been implicated in its pathogenesis. Considering the recently defined regulatory mechanisms of NK cells through HLA class I binding receptors, we hypothesized that interactions of NK and T cells through the NK receptors may be important in the pathogenesis of BD. METHODS: The impact of different expression patterns of HLA-recognizing receptors on NK or T cells was analysed in 51 patients with BD and 32 healthy controls. We used flow cytometry to investigate the expression of KIR3DL1 from the polymorphic killer immunoglobulin-like receptor (KIR) family, which binds a shared HLA-Bw4 motif on HLA-B51 and *2702 alleles, and CD94 from the conserved C-type lectin receptor family, which binds HLA-E. Thirty-three of the BD patients and 19 of the controls carried the same HLA-Bw4 motif. RESULTS: CD3(+) T cells were increased in patients with BD compared with controls (81 vs 75%, P = 0.001), whereas the NK cells did not show any difference between the two groups. Increased expression of CD94 in BD was observed on CD16(+)CD56(+) cells (66 vs 57, P = 0.04) and on CD3(+) (7.7 vs 4.0, P < 0.001) and CD3(+)CD56(+) (44 vs 35, P = 0.02) T cells. KIR3DL1 expression on the NK and T cells was not statistically different between the two groups. No effect of HLA-Bw4 motif was observed on the expression of CD94 and KIR3DL1 in both the patients and the controls. CONCLUSION: The absence of a correlation between KIR3DL1 expression and HLA-Bw4 motif confirms previous work reporting that the expression of these molecules is regulated separately. Increased expression of CD94 may suggest that NK receptors play a pathogenic or regulatory role in BD.     

Human leukocyte antigen-B*2705 is the predominant subtype in the Korean population with ankylosing spondylitis,unlike in other Asians

This study was performed to investigate the frequency of human leukocyte antigen (HLA)-B27 subtypes in the Korean population with spondyloarthropathy (SpA). We determined the HLA subtypes of 267 SpA patients who were positive for the B27 antigen (as determined by serology) by using a PEL-FREEZ kit (Dynal Biotech, Wisconsin, USA). Clinical features, including sex, peripheral joint involvement, and the presence of uveitis, were analyzed in a retrospective cohort study. Among 267 patients, 244 were B*2705-positive and 22 were B*2704-positive. One patient was positive for B*2704/2705. No other subtype was observed among the analyzed patients. We found that HLA-B*2705 was the predominant subtype in Koreans with SpA; this finding is remarkable because other Asians such as the Han or the Japanese exclusively have the B*2704 subtype. This result suggests that the clinical features and prevalence of SpA in Koreans may be similar to those observed in Europeans.     

HLA-B27 subtypes in Turkish patients with ankylosing spondylitis and healthy controls

The aim of this study was to determine human leukocyte antigen (HLA)-B27 subtypes frequency in ankylosing spondylitis (AS) and related spondyloartropathy (SpA) patients. Therefore, we investigated the differences in HLA-B27 subtypes between HLA-B27-positive patients and controls. Sixty six patients were included in this study (51 AS and 15 SpA). Thirty-five individuals were diagnosed with leukemia or chronic renal failure, and their donors without any rheumatological problem (no SpA history) were selected as the control group. HLA-B27 subtyping was performed by PCR-SSP (polymerase chain reaction with sequence-specific primer) method in serologically HLA-B27-positive 46 AS patients, 9 SpA patients and control group. When the frequency of HLA-B27 was 4.5% in Turkish population, this frequency was 90.2% in AS patients. Four different HLA-B27 subtypes found in AS patients were B*2705 (65.2%), B*2702 (26.1%), B*2704 (6.5%) and B*2707 (2.2%). In SpA patients, B*2705 and B*2702 found in equal frequency. Five B27 alleles were identified in our control group: B*2705 (54.3%), B*2702 (31.4) %, B*2703 (2.9%), B*2704 (2.9%) and B*2702/B*2705 (8.5%). Both in the patient group and in the control group, we also observed B*2705 as most frequent allele, and B*2702 was second common allele. Our results show that the frequency of HLA-B27 subtypes is not significantly different between patients and controls (P?>?0.10).     

HLA antigens and juvenile onset spondyloarthritides: negative association with non-B27 alleles

OBJECTIVE: To describe the association between HLA-B and HLA-DR genes and juvenile onset spondyloarthritides (SpA) in Mexicans. METHODS: The study included 66 consecutive patients with SpA (45 with ankylosing spondylitis (AS) and 21 with undifferentiated SpA) and 99 non-related healthy controls. The HLA-A, -B and DR alleles were detected by the polymerase chain reaction with the sequence-specific primers technique. Statistical methods included the Mantel-Haenzel chi2 test, Fisher's exact test, and Woolf method for odds ratio (OR). RESULTS: The frequency of HLA-B27 was significantly increased in the whole group (pC < 10(-3), OR = 53.0, aetiological fraction = 51%), particularly in AS (pC < 10(-3), OR = 67.42, aetiological fraction 57%). In contrast, the frequencies of HLA-B44, and HLA-B14 were significantly decreased. Also, a weak negative association HLA-DR5 (p < 0.05) was found. CONCLUSION: Apart from an expected significant association between HLA-B27 and juvenile-onset SpA, particularly AS, we found negative associations with HLA-B44, B14, and DR5. There was also a trend for HLA-B15 and DR1 associations with SpA.     

Down-regulation of HLA-A and HLA-Bw6, but not HLA-Bw4, allospecificities in leukemic cells: an escape mechanism from CTL and NK attack?

Human leukocyte antigen (HLA) class I antigen defects may have a negative impact on the growing application of T-cell-based immunotherapeutic strategies for treatment of leukemia. Therefore in the present study, taking advantage of a large panel of HLA class I allele-specific human monoclonal antibodies, we have compared HLA class I antigen expression on leukemic cells with that on autologous and allogeneic normal cells. Down-regulation of HLA-A and/or -B allospecificities was present in the majority of the patients studied. However, down-regulation did not affect all HLA class I alleles uniformly, but was almost exclusively restricted to HLA-A allospecificities and to HLA-B allospecificities which belong to the HLA-Bw6 group. The latter allospecificities, at variance from those that belong to the HLA-Bw4 group, do not modulate the interactions of leukemic cells with natural killer (NK) cells. Therefore, our results suggest that the selective down-regulation of HLA-A and HLA-Bw6 allospecificities associated with HLA-Bw4 preservation provides leukemic cells with an escape mechanism not only from cytotoxic T lymphocytes (CTLs), but also from NK cells. As a result T-cell-based immunotherapeutic strategies for leukemia should utilize HLA-Bw4 alloantigens as restricting elements since a selective HLA-Bw4 allele loss would provide leukemic cells with an escape mechanism from CTLs, but would increase their susceptibility to NK cell-mediated lysis.     

Natural killer lymphocytes in hairy cell leukemia: presence of phenotypically identifiable cells with defective functional activity

Eleven patients with hairy cell leukemia (HCL) were studied to determine the number and function of circulating natural killer (NK) lymphocytes in this disorder using a well-defined surface marker of these cells (Mac-1), the fluorescence-activated cell sorter (FACS), and a standard 51Cr release assay to determine cytotoxicity against the K562 cell line. Four of these patients demonstrated normal numbers of phenotypic and morphological (large granular lymphocyte) NK cells in the blood, but these cells showed a severe functional deficiency in their ability to lyse the K562 target. Sorting experiments demonstrated that although all of the NK activity was contained within the phenotypically identifiable NK population, the defect in NK function persisted even when these cells were isolated from other cell populations. Of the remaining seven patients, two had normal numbers and function of NK cells and five showed a marked deficiency of both phenotypic NK cells in the blood and NK function. These data suggest that the marked in vitro functional deficiencies of NK activity that occur in a majority of patients with HCL are sometimes associated with the preservation of phenotypically identifiable NK cells that are qualitatively rather than quantitatively deficient.     

Spondyloarthropathies in eastern Asia

The association between HLA-B27 and the spondyloarthropathies (SpAs) is so strong that it is supposed that the HLA-B27 molecule plays a pathogenetic role. In whites and Indonesians, the frequency of HLA-B27 is about 10%; in Chinese it is about 8%; and in Japanese it is only about 1%. The prevalence of SpA in the Chinese is at least 0.2%, but in native Indonesians, Philippinos, and Malaysians, SpA is rarely seen. Twenty-three subtypes (B*2701-B*2723) have been distinguished. These subtypes are not equally distributed over the world. In most countries the distribution of the subtypes among HLA-B27 SpA patients is the same as that among the normal HLA-B27-positive population. In China, the subtype B*2704 is frequent and the prevalence of SpA is high. Native Indonesians, however, mostly have subtype B*2706, and SpA is rarely seen in this population. It was shown that B*2706, probably like B*2709 in Sardinia, is not associated with SpA. The difference between the SpA-associated and non-SpA-associated subtypes is limited to only two amino acid residues (114 and 116) at the bottom of the peptide-binding groove of HLA-B27. This small difference between health and disease rewards studies for different peptide-binding capacities and may help us characterize the peptides that are involved in the pathogenesis of SpA.The differences in disease associations in these countries also have clinical implications. In Southeast Asia, HLA-B27 typing without subtyping has less clinical usefulness than in parts of the world where B*2706 is rarely seen. When native Indonesians, Malaysians, or Philippinos are suspected of having ankylosing spondylitis or a related SpA, it is worth asking if they had white or Chinese ancestors. If native HLA-B27-positive Indonesians (with subtypes other than B*2706) develop SpA, the clinical features are not different from those in other parts of the world. In the Chinese population on the mainland and in Taiwan, juvenile SpA is frequently seen. The onset is often a peripheral arthritis or enthesitis.