ABSTRACT
Objective To investigate the concurrent application value of indirect immunofluorescence (IIF) and enzyme-linked immunosorbent assay (ELISA) in systemic lupus erythematosus (SLE).Methods A retrospective study.All patients who took anti-double stranded DNA (dsDNA) antibody test from June 1 2011 to September 30 2011 in our department were recruited in this study.The patients' anti-dsDNA antibody results and clinical diagnosis were collected and analyzed retrospectively.The consistence,sensitivity and specificity of IIF and ELISA tests were calculated and the consistence was compared by Kappa test.Results The positive rates of detecting anti-dsDNA antibodies by ELISA and IIF tests were 16.3％ and 13.1％ respectively.The consistency between these two tests was 90.8％,and showed good correlation by Kappa test (Kappa =0.641,P ＜ 0.05 ).Of 9.2％ of inconsistent results between IIF andi ELISA,most cases ( 6.2％ ) were ELISA positive and IIF negative.Taking the clinical diagnosis of lupus as a golden standard,the accuracy of IIF and ELISA was 84.8％ and 84.4％ respectively and the difference was no significant (x2 =0.25,P ＞ 0.05 ).The sensitivity and specificity for diagnosing lupus by IIF were 46.1％ and 99.2％,and 51.3％ and 96.7％ by ELISA.Conclusions Our results suggested that anti-dsDNA antibodies in samples should be detected by both ELISA and IIF tests simultaneously.If ELISA was used first and the positive samples were further tested by IIF,at least 3％ of ELISA negative and IIF positive samples would be misdiagnosed as anti-dsDNA antibodies negative.IIF negative and ELISA positive samples should be further analyzed the affinity of anti-dsDNA antibodies in order to help the diagnosis and evaluation of SLE.
ABSTRACT
Objective This study was designed to investigate positive rate of serum antibody and the distribution of serotypes of Legionella pneumophila in the patients of author's hospital for recent 5 years.Methods All the inspecting results of antibodies in the 1212 serums by indirect immunofluorescence from Jan 1, 2003 to Oct 31, 2007 were reviewed. The clinical information of patients was collected.Results 163 serums were positive (13.5%). Serotype 4 had the highest positive rate of 12.0% followed by serotype 12 (8.5%), 5 (7.8%), 14 (6.1%), 10 (5.9%). Three simultaneously positive serotypes were dominant (21.0%), and 4 or 5 simultaneously positive serotypes were common. In all departments, the highest positive rate (23.3%) was in respiratory ward, in which serotype 4 and 12 were the most (19.0% and 17.2%, respectively).Conclusions Serotype 4 was the most common type of Legionella pneumophila in serotype 1-14. Cross reaction could exist between Legionella pneumophila and other pathogenic microorganism or in different serotypes.
ABSTRACT
Objective To investige the sensitivity and specificity of anti-proteinase 3 (PR3) capture ELISA in diagnosis of Wegener's granulomatosis (WG),and the correlation between the capture ELISA and indirect immunofluorescence assay (IIF).Methods Anti-PR3 antibody and anti-neutrophil cytoplasmic antibody (cANCA) in sera from 72 patients with WG,206 healthy blood donors and 24 patients with autoimmune diseases were detected by classic ELISA,capture ELISA and IIF.Results The sensitivities of classic ELISA and capture ELISA for detection of anti-PR3 in WG diagnosis were 73.6% and 87.5% respectively.The specificities of both the ELISAs were identical (100%).Detection of anti-PR3 by ELISA or IIF alone led to the serological hit rate of 87.5% and 84.7% for WG respectively,but the combination of capture ELISA and IIF increase the hit rate up to 91.6%.Conclusions The sensitivity of anti-PR3 capture ELISA as well as its correlation with IIF is prior to classic anti-PR3 ELISA.The combined detection of anti-PR3 capture ELISA and IIF may increase the diagnosis rate of clinically suspected WG.