肾移植受者硫嘌呤甲基转移酶基因多态性与硫唑嘌呤不良反应关系的研究

目的:探讨硫嘌呤甲基转移酶(thiopurine S-methyltransferase,TPMT)表型和基因多态性与硫唑嘌呤(AZA)所致不良反应的关系。方法:应用高效液相色谱法(HPLC)测定150例肾移植患者红细胞TPMT活性,采用等位基因特异性的PCR和限制性片断长度多态性的方法检测TPMT*2、*3A、*3B和*3C四种基因型,分析TPMT活性和基因多态性与AZA所致不良反应的关系。结果:30例(20%)患者由于发生了不良反应而停用AZA或减少了AZA的用量,其中12例患者发生了血液毒性,另外18例发生了肝脏毒性。将未发生不良反应的患者作为对照组,其红细胞TPMT活性范围为16.63~68.25 U,平均为(38.43±11.59)U。发生了血液毒性的患者红细胞TPMT活性平均为(24.16±9.84)U,明显低于未发生不良反应的患者(P=0.0003)。另外18例发生了肝脏毒性的患者TPMT活性离散度较大,与对照组比较差异无统计学意义(P=0.145)。本研究未发现TPMT活性缺乏者。共发现7例(4.7%)TPMT*3C杂合子患者,这7例患者均为TPMT中等活性13.04~19.21 U,平均为(...     

肾移植患者HGPRT活性及多态性与硫唑嘌呤所致不良反应的相关性研究

目的:本研究旨在探索次黄嘌呤鸟嘌呤磷酸核糖转移酶(HGPRT)活性及基因多态性与硫唑嘌呤(AZA)所致不良反应的相关性,为临床合理使用AZA提供理论依据。方法:用本实验室建立的HPLC法测定入选样本的HGPRT活性,直接测序法测定HGPRT IVS6-12C>A的基因型,结合受试者不良反应发生情况,分析HGPRT活性及多态性与AZA所致不良反应的相关性。结果:86例肾移植受者HGPRT活性范围为(44.59~262.16)U,平均为(100.17±33.50)U,健康受试者HGPRT活性范围为(28.43~153.65)U,平均为(99.30±17.21)U,均呈正态分布。两组HGPRT活性均值差异无统计学意义(P>0.05)。304例肾移植患者中发现2例HGPRT IVS6-12C>A突变体,突变频率为2.30%。而健康受试者中未发现突变,分析发现HGPRT活性与基因型之间无明显相关性(P>0.05)。流行性感冒样症状组患者的平均HGPRT活性明显高于肾移植对照组[(147.47±101.24)Uvs(100.46±29.31)U,P<0.05)],而血液毒性组、肝脏毒性组、胃肠道反应组与肾移植对照组比较,活性差异无统计学意义。AZA所致不良反应与HGPRT基因多态性之间没有明显相关性(P>0.05)。结论:在服用AZA之前,测定患者HGPRT活性,筛选出HGPRT高活性者,减少AZA的初始剂量,有利于减少AZA所致流行性感冒样症状不良反应的发生率。     

硫嘌呤类药物遗传药理学研究进展

临床上硫嘌呤类药物应用广泛,但在此类药物的使用过程中,血液毒性、肝脏毒性、胰腺炎等不良反应的发生率较高。研究发现,硫嘌呤甲基转移酶(thiopurine S-methyltransferase,TPMT)的活性和遗传多态性,以及三磷酸肌苷焦磷酸酶(inosine triphosphate pyrophosphatase,ITPA)的遗传多态性与硫嘌呤类药物不良反应的发生密切相关。本文综述了TPMT活性和基因多态性,以及ITPA基因多态性的研究进展。     

中国健康汉族和瑶族人群巯基嘌呤甲基转移酶活性的分布

目的研究巯基嘌呤甲基转移酶(TPMT)活性在中国汉族和瑶族人群中的分布。方法建立改良的反相高效液相色谱法,测定人红细胞(RBC)中TPMT活性。结果测定了273名中国健康汉族成年人、88名汉族儿童和148名健康瑶族儿童红细胞中TPMT活性,未发现酶缺陷者,其平均活性分别为(11.96±3.27),(13.02±2.78)和(13.27±3.92)nmol·(h·mL)-1packed红细胞。瑶族儿童TPMT活性较同龄汉族儿童差异无显著性;TPMT活性在中国汉族和瑶族人群中都呈正态分布;在中国汉族和瑶族人群中均未发现有与性别有关的差异;汉族人群TPMT活性与年龄无关;瑶族儿童TPMT活性与年龄呈正相关,但相关关系较弱。结论中国汉族和瑶族人TPMT活性分布均呈正态分布。     

正常中国汉人红细胞中儿茶酚氧位甲基转移酶的活性测定

目的测定正常中国人群红细胞儿茶酚氧位甲基转移酶(COMT)活性浓度值,为研究COMT活性变化在疾病诊断中的应用提供依据。方法采用高效液相色谱法测定279名正常健康人(其中男性134例,女性145例)红细胞中COMT的活性浓度,用SPSS统计软件对性别间测定结果进行检验比较。结果男性和女性红细胞中COMT活性浓度分别为:(16.5±7.4)、(15.5±5.3)nmol.mL RBC-1.h-1。活性频率分布男性在6.0~37.4nmol.mL RBC-1.h-1,女性为5.4~37.2 nmol.mL RBC-1.h-1,男女之间COMT活性浓度的差异无统计学意义(P>0.05)。结论本法灵敏,简便,准确,重复性好,且测定结果与国外一些报道一致,适用于临床应用测定研究。本结果可作为中国健康人红细胞COMT活性正常值及今后研究的重要参考数据。     

复方丹参滴丸对人肝脏药物代谢酶CYP1A2活性的影响

目的:研究复方丹参滴丸对人肝脏药物代谢酶CYP1A2活性的影响,指导临床合理用药。方法:采用反相高效液相色谱法测定服用复方丹参滴丸前、后人尿液内咖啡因4种主要代谢产物的相对含量;采用(AFMU+1X+1U)/17U比率法评价人肝脏药物代谢酶CYP1A2活性的变化。结果:受试者用药前CYP1A2的平均活性为4·20±1·54,服用复方丹参滴丸14d后CYP1A2的平均活性为4·26±1·95,用药28d后CYP1A2的平均活性为4·35±1·26,二者分别比用药前升高1·42%和3·57%,但无统计学差异。结论:服用治疗剂量的复方丹参滴丸对人肝脏药物代谢酶CYP1A2的活性无明显影响,不会影响与之合用的需经CYP1A2代谢药物的疗效。     

硫唑嘌呤不良反应的临床表现与安全用药

目的探讨硫唑嘌呤不良反应(ADR)发生的类型及其临床表现,为临床安全用药提供参考。方法检索国外有关硫唑嘌呤不良反应的病例报道,进行分析和总结。结果硫唑嘌呤的不良反应以血液系统损害最为多见,其次为肝功能损害、感染、胃肠道反应、肺毒性等不良反应。其中骨髓抑制、肺毒性、肝脏毒性可致命。结论临床医药人员应重视硫唑嘌呤引起的ADR,观察患者用药表现,以减少严重ADR的发生。     

安乃近滴液在正常人体内的生物利用度

比较了6例健康志愿者,单剂量po lg安乃近滴液和单剂量po lg安乃近片剂的生物利用度。采用高效液相色谱法,测定受试者体内安乃近的活性代谢产物,4-甲氨基安替比林(MAA)血浆浓度。其MAA在血浆中的达峰时间(Tp):滴液组平均为1.08±0.25h,片剂组平均为1.36±0.13h,(P<0.05)。其相对生物利用度(F=RUC滴液/AUC片剂)为1.26±0.44,P>0.05。     

基因重组人红细胞生成素治疗类风湿性关节炎贫血

目的　观察基因重组人红细胞生成素 (rh Epo)治疗类风湿性关节炎贫血 (ARA)患者的临床疗效及不良反应。方法　 6例患者用rh Epo 2 0 0 0U皮下注射 ,隔日 1次 ,疗程 4周。结果　患者血清Epo、Hb、RBC、网织红细胞 (Ret)、红细胞比积 (HCT)均明显升高 ,其中Hb从 (84 5 0± 8 83)g/L升至 (97 33± 15 2 1) g/L ,有 1例患者Hb从 97g/L升至 12 1g/L。无临床不良反应发生。 结论　rh Epo治疗ARA患者安全有效 ,在使用rh Epo过程中 ,适量补铁是需要的 ,而有效地控制风湿活动及适当增加rh Epo剂量 ,可能会进一步提高疗效。     

急性白血病患者化疗前后肿瘤相关物质群检测的临床意义

目的探讨恶性肿瘤相关物质群(Tumorsuppliedgroupoffactors,TSGF)检测在急性白血病(AL)患者疗效观察及预后判断中的价值。方法采用福建新大陆生物技术有限公司提供的TSGF检测试剂盒,对47例AL初治患者、8例复发患者及15例健康献血员血清TSGF水平进行测定。结果47例AL初治患者血清TSGF水平为78.47±14.71U/ml,8例复发患者血清TSGF水平为74.62±15.03U/ml,均明显高于对照组水平(51.29±7.54U/ml),差异非常显著(t=6.847,5.009,P<0.001);完全缓解(CR)组(11例)血清TSGF水平(56.15±9.18U/ml)明显下降,其水平与正常对照组比较无显著性差异(t=1.482,P>0.05);难治组血清TSGF水平(90.08±13.01U/ml)明显高于非难治组的水平(73.44±13.21U/ml),两者具有显著性差异(t=3.878,P<0.001)。结论TSGF对急性白血病患者疗效观察及预后判断有重要价值。     

中国汉族人三磷酸肌苷焦磷酸酶活性的分布

目的：研究三磷酸肌苷焦磷酸酶（ITPA）活性在中国汉族人中的分布。方法：运用HPLC法测定402名健康汉族人红细胞的ITPA活性。结果：不同性别、不同血型汉族人的红细胞ITPA活性均值差异无统计学意义（P〉0．05）,其ITPA活性呈双峰分布,活性缺乏率为27．6％。此外发现6例ITPA活性缺乏者,占研究总人数的1．47％。结论：中国汉族人红细胞ITPA活性呈双峰分布。     

ITPA Activity in Children Treated by Azathioprine: Relationship to the Occurrence of Adverse Drug Reactions and Inflammatory Response

Azathioprine (AZA), a thiopurine drug, is widely used in the treatment of children with immunological diseases such as inflammatory bowel disease (IBD) and autoimmune hepatitis (AIH); however, interindividual variability in the occurrence of adverse drug reactions (ADRs) and drug response is observed. This study investigated (i) the relationships between inosine triphosphate pyrophosphatase (ITPA) activity, an enzyme involved in thiopurine metabolism, and the occurrence of ADRs in children with immunological disease on AZA therapy, and (ii) the relationship between ITPA activity and the inflammatory activity observed in children with IBD. ITPA and TPMT activities were determined in 106 children with immunological disease on AZA therapy. Markers of hepatotoxicity, myelotoxicity, pancreatitis and inflammation as well as clinical information were retrospectively collected during regular medical visits. No significant association was found between ITPA activity and hepatotoxicity or clinical ADRs such as cutaneous reactions, arthralgia, flulike symptoms and gastrointestinal disorders. Concerning myelotoxicity, a significant relation was observed between ITPA activity and RBC mean corpuscular volume (MCV; p=0.003). This observation may be related to the significant relationship found between high ITPA activity and the increase in γ‐globulin level reflecting inflammation (p=0.005). In our study, ITPA activity was not associated with occurrence of ADRs, but a relationship between high ITPA activity and γ‐globulin, a marker of inflammation, was found in children with IBD. Therefore, measurement of ITPA activity may help to identify children with IBD predisposed to residual inflammation on AZA therapy. Further prospective studies are needed to confirm this result.     

Adverse drug reactions to azathioprine therapy are associated with polymorphism in the gene encoding inosine triphosphate pyrophosphatase (ITPase)

Adverse drug reactions to azathioprine (AZA), the pro-drug of 6-mercaptopurine (6-MP), occur in 15% to 28% of patients and the majority are not explained by thiopurine methyltransferase (TPMT) deficiency. Inosine triphosphate pyrophosphatase (ITPase) deficiency results in the benign accumulation of the inosine nucleotide ITP. 6-MP is activated through a 6-thio-IMP intermediate and, in ITPase deficient patients, potentially toxic 6-thio-ITP is predicted to accumulate. The association between polymorphism in the ITPA gene and adverse drug reactions to AZA therapy was studied in patients treated for inflammatory bowel disease. Sixty-two patients with inflammatory bowel disease suffering adverse drug reactions to AZA therapy were genotyped for ITPA 94C>A and IVS2 + 21A>C polymorphisms, and TPMT*3A, *3C, *2 polymorphisms. Genotype frequencies were compared to a consecutive series of 68 controls treated with AZA for a minimum of 3 months without adverse effect. The ITPA 94C>A deficiency-associated allele was significantly associated with adverse drug reactions [odds ratio (OR) 4.2, 95% confidence interval (CI) 1.6-11.5, P = 0.0034]. Significant associations were found for flu-like symptoms (OR 4.7, 95% CI 1.2-18.1, P = 0.0308), rash (OR 10.3, 95% CI 4.7-62.9, P = 0.0213) and pancreatitis (OR 6.2,CI 1.1-32.6, P = 0.0485). Overall, heterozygous TPMT genotypes did not predict adverse drug reactions but were significantly associated with a subgroup of patients experiencing nausea and vomiting as the predominant adverse reaction to AZA therapy (OR 5.5, 95% CI 1.4-21.3, P = 0.0206). Polymorphism in the ITPA gene predicts AZA intolerance. Alternative immunosuppressive drugs, particularly 6-thioguanine, should be considered for AZA-intolerant patients with ITPase deficiency.     

Analysis of ITPA phenotype-genotype correlation in the Bulgarian population revealed a novel gene variant in exon 6

Mutations in the inosine triphosphate pyrophosphohydrolase (ITPA) gene causing enzyme deficiency were shown to have pharmacogenetic implications in azathioprine-induced adverse drug reactions. The distribution of ITPA activity as well as the types and the frequencies of gene variants associated with a lower enzyme activity were determined in healthy volunteers from a Bulgarian population. The ITPA activity was measured in 185 erythrocyte samples by an established high-performance liquid chromatography procedure. All samples were genotyped for 94C > A, IVS2 + 21A > C, and IVS2 + 68T > C/G by real-time polymerase chain reaction with hybridization probes. The ITPA activity ranged from 7.5 to 587.8 micromoL IMP/(g Hb x h) with a median value of 162.9 micromoL IMP/(g Hb x h). The enzyme activity showed significant differences between females and males (P = 0.006) with 17% higher values in men than women. Mutant allele frequencies were 0.038 (94C > A) and 0.130 (IVS2 + 21A > C). Mutations at IVS2 + 68 were not identified. Using a cutoff at 75 micromoL IMP/(g Hb x h) phenotyping detected all heterozygous carriers of 94C > A, two compound heterozygotes, all IVS2 + 21A > C homozygotes and 12.5% of IVS2 + 21A > C heterozygous cases. A novel frameshift mutation 359_366dupTCAGCACC in exon 6 was found in a subject with reduced enzyme activity of 61.2 micromoL IMP/(g Hb x h). The interindividual variability in ITPA activity among the Bulgarian population resembles the distribution of enzyme activity in other whites, although the observed median activity was approximately 25% lower in the Bulgarians [163 vs 219 micromoL IMP/(g Hb x h)]. The most common mutant allele IVS2 + 21A > C showed a similar frequency like in other white populations, whereas the 94C > A mutation was less frequently observed compared with other whites. Heterozygosity for the novel gene variant 359_366dupTCAGCACC was associated with 30% enzyme activity of the wild-type median value. The role of this rare variant for the thiopurine intolerance is not explored. These data further extend the knowledge for ITPA heterogeneity in whites.     

Inosine triphosphate pyrophosphatase 94C> A polymorphism: clinical implications for patients with systemic lupus erythematosus treated with azathioprine

Importance of the field: Azathioprine (AZA) has immunosuppressive property and has been widely used in organ transplantation and in several autoimmune diseases including systemic lupus erythematosus. The use of AZA is limited by the occurrence of adverse drug reactions (ADRs) leading to treatment discontinuation. Under AZA therapy, inosine triphosphate pyrophosphatase (ITPA) deficiency presumably leads to accumulation of unusual thioinosine metabolites with the potential for ADRs. Japanese patients require lower doses of AZA compared with Caucasian patients to achieve the same concentration of active metabolites. This ethnic difference in part is probably due to genetic polymorphisms of ITPA.

Areas covered in this review: Relationships between ITPA genotype and enzyme activity, and efficacy and toxicity of AZA in both Caucasian and Asian populations are reviewed.

Take home message: Clinical studies using a dose of <?1.5 mg/kg/day in various autoimmune diseases have shown no association between ITPA genotype and ADRs. In studies using higher doses, ITPA deficiency appears to increase the risk for AZA toxicity. Genotyping of ITPA may be useful to achieve dose optimization. It is important to maintain the dose of AZA <?1.5 mg/kg/day for Asian patients with ITPA 94A allele, with careful monitoring of the therapeutic efficacy.     

Pharmacogenetics of thiopurine therapy in paediatric IBD patients

BACKGROUND: Azathioprine is widely used in the treatment of children with inflammatory bowel disease. The occurrence and type of adverse events to azathioprine may be related to thiopurine S-methyltransferase (TPMT) enzyme activity and to inosine triphophate pyrophosphatase (ITPase) deficiency. AIM: Investigate frequencies of functional TPMT polymorphisms and ITPA polymorphisms and their association with the occurrence of adverse events during azathioprine therapy in a paediatric inflammatory bowel disease population. METHODS: Seventy-two azathioprine treated paediatric inflammatory bowel disease patients, 47% girls, mean age 12.5 years (range 6.5-17.5), were assessed for TPMT and ITPA polymorphisms and for adverse events. The relation between polymorphisms and adverse events is evaluated. RESULTS: Of all azathioprine treated patients, 11 experienced an adverse event for which azathioprine was stopped: pancreatitis (n = 4), leucopenia (n = 2) and 'general malaise' (n = 5). Of the 11 patients who stopped azathioprine because of adverse events, 10 had wild-type alleles for all investigated genotypes. Genotyping of ITPA 94C>A polymorphisms showed that two patients were homozygous, both tolerated azathioprine well. CONCLUSIONS: No association of functional ITPA and TPMT polymorphisms and the occurrence of azathioprine related adverse events could be detected. Pharmacogenetic assessment prior to thiopurine therapy does not seem warranted.     

Lack of association between the ITPA 94C>A polymorphism and adverse effects from azathioprine

A 94C>A missense mutation in the ITPA gene which encodes inosine triphosphate pyrophosphatase has been associated with adverse effects from azathioprine, specifically flu-like symptoms, pancreatitis and rash. We hypothesized that this association may also be present in a larger, population-based group of inflammatory bowel disease patients intolerant of thiopurine drugs. We performed genotyping for this polymorphism and TPMT*2 and TPMT*3 in 73 such patients and 74 patients with inflammatory bowel disease who have tolerated azathioprine. We could not demonstrate a significant association between the ITPA94C>A genotype and any adverse effects (Odds ratio (OR) 1.015, 95% confidence interval (CI) 0.360-2.867, P = 0.593), flu-like symptoms (OR 1.547, 95%CI 0.368-6.496, P = 0.398), rash (no ITPA 94C>A polymorphism identified) or pancreatitis (no ITPA 94C>A polymorphism identified). We found no significant association between the ITPA 94C>A polymorphism and adverse effects to thiopurine drugs.     

左乙拉西坦联用维生素B6对药物不良反应的影响

目的：观察左乙拉西坦与维生素B6联用对其药物不良反应的影响。方法：回顾性分析2010年1月-2015年6月就诊于神经内科癫痫专科并随访大于24周的患者110例。根据自愿原则将110例门诊患者随机分为研究组（左乙拉西坦+维生素B6）和对照组（单用左乙拉西坦），在治疗后的4、12、24周动态随访其疗效和不良反应。结果：治疗24周后，研究组行为的不良反应包括兴奋、攻击、烦躁、激惹等副作用的出现明显低于对照组（P<0.05）。结论：联用维生素B6对左乙拉西坦药物不良反应的影响有一定的改善。     

别嘌醇不良反应临床案例分析

目的通过对我院临床案例的分析,获得近年别嘌醇不良反应发生及治疗的总体趋势、特点及相关因素,为临床安全合理用药提供依据。方法根据我院临床110例案例,总结归纳别嘌醇引起的不良反应。结果临床案例共110例,其中死亡4例（3.64%）。最常见的不良反应均为皮肤-黏膜反应,占100%,其主要表现为药疹。其次是发热,血液系统损害、肝、肾功能损害等不良反应。结论临床上使用该药时应加强药品不良反应监测。