ABSTRACT
BACKGROUND: Human leukocyte antigen (HLA)-B27 is closely connected to the occurrence of some rheumatic diseases such as ankylosing spondylitis and can be used as an important factor for evaluating the diagnosis of ankylosing spondylitis. Immunomagnetic separation and enzymelinked immunosorbent assay (IMS-ELISA) has been applied to the detection of HLA-B27.OBJECTIVE: To explore the accuracy, sensitivity and specificity of IMSELISA for detecting HLA-B27 and its value in the auxiliary diagnosis of ankylosing spondylitis.DESIGN: A clinical trial in comparison with the gold standard.SETTING: Departments of Rheumatology and Clinical Laboratory, Third Affiliated Hospital of Sun Yat-sen University.PARTICIPANTS: Eighty-six patients suffering from low back pain and/or arthritis who were treated for the first time in Department of Rheumatology from December 2002 to April 2003. Inclusion criteria: ① Presence of manifestations of low back pain and/or arthritis; ② Thorough documentation of clinical and other examinations; ③ Informed consent to HLA-B27 examination; ④ Treatment for the first time in the Third Affiliated Hospital of Sun Yet-sen University. Those with other serious diseases or with incomplete record of clinical and/or accessory examinations were excluded. The 86 patients included 56 male and 30 female patients aged from 12 to 65 years.METHODS: Blood sample was detected for HLA-B27 by both IMS-ELISA and microlymphocytotoxicity test, and the latter was selected as the gold standard. The coincidence rate of the results detected by the two methods as well as the sensitivity, specificity, positive and negative predictive values of IMS-ELISA were calculated.MAIN OUTCOME MEASURES: ① The coincidence rate of the results of the two methods. ② The sensitivity and specificity of IMS-ELISA for detecting HLA-B27.RESULTS: None of the patients was lost. For the 33 patients with ankylosing spondylitis, the positivity rate of IMS-ELISA (90.9％) was higher than that of microlymphocytotoxicity test (87.9％), but the difference was not statistically significant (P＞0.05). The total coincidence rate of the two methods was 93.0％ in all the 86 patients. The sensitivity, specificity, positive and negative predictive values of IMS-ELISA were 90.0％, 95.7％,94.7％ and 91.7％ respectively.CONCLUSION: Both IMS-ELISA and microlymphocytotoxicity test are capable of reliable examination of HLA-B27 with high sensitivity and specificity.
ABSTRACT
AIM: To study the expression of hepatitis B virus core gene in Pichia pastoris and to obtain high-level expressed recombinant HBcAg with good immunoreactivity and high specificity. METHODS: HBV core gene was amplified by PCR from plasmid pHBV1 which contained HBV whole DNA sequence. The PCR product was cloned into pGEM-T vector by TA cloning strategy. After confirmed by DNA sequence analysis, the gene of interest was inserted into the yeast expression vector pPIC9. The recombinant plasmid pPIC9-cAg was constructed and transformed into GS115 by electroporation. The recombinant yeast GS115 was induced by 0.5% methanol. The expressed product was analysed by SDS-PAGE,Western blot and ELISA. RESULTS: The restriction analysis and DNA sequence analysis proved that HBV core gene had already been cloned to yeast expression plasmid pPIC9. The expressed HBcAg existed in SDS-PAGE. Good immunoreactivity and high specificity of the recombinant HBcAg have been proved by ELISA and Western blot. The titre of the recombinant HBcAg in the cell lysate was 1∶ 12 800 . CONCLUSION: The recombinant plasmid pPIC9-cAg was successfully constructed. The recombinant HBcAg with good immunoreactivity and high specificity was successfully expressed in Pichia pastoris expression system and can be applied to further developing HBcAb immunoassay. [
ABSTRACT
AIM: To investigate the pentanucleotide repeat(PNR) polymorphism of apolipoprotein(a) in patients with coronary heart disease(CHD) in Hubei area, and evaluate the association of polymorphism of apo(a) PNR with the level of serum lipid. METHODS: Objects examined were composed of two groups: 88 patients with CHD and 153 healthy controls. Lp(a), TC,TG, HDL-C, LDL-C, ApoAⅠand ApoB of two groups were tested. Meanwhile,the PNR in the 5' control region of the Apo(a) was detected by using polymerase chain reaction (PCR) and high voltage polyacrylamid gels electropherosis. RESULTS: The serum Lp(a), TC, TG and LDL-C levels were remarkably higher in the CHD than that in control( P