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<snip>Shah JS, Du Cruz I, Narciso W, Lo W and Harris NS. Improved Sensitivity of Lyme disease Western
Blots Prepared with a Mixture of Borrelia Burgdorferi Strains 297 and B31. Chronic Dis Int. 2014;1(2): 7.
Received:October 28, 2014;Accepted:December 08, 2014;Published: December 10, 2014
Testing for Borrelia burgdorferi (BB), the spirochetal agent of Lyme disease, is problematic due to poor sensitivity of commercially available serological tests. We evaluated an in-house Western Blot (WB) prepared with a mixture of two strains of BB, B31 and 297. Sensitivity and specificity of IgG and IgM testing using the two-strain WB was compared to testing with a commercial single-strain WB, and interpretation of the in-house WB using in-house criteria was compared to interpretation using criteria recommended by the Centers for Disease Control and Prevention (CDC). A total of 364 control and patient sera (including 88 from treated patients with confirmed Lyme disease) were tested. The sensitivity of the combined IgG and IgM commercial WB using CDC criteria was 77.1%. When the in-house IgG and IgM WB and CDC criteria were used, the combined sensitivity improved to 88.6 %, while use of the in-house IgG and IgM WB and in-house interpretation criteria resulted in a combined sensitivity that increased to 97.1%. Using CDC criteria, the specificity of the in-house IgG and IgM WB was 100% and 97.1%, respectively; using in-house criteria; the specificity was 95.3% and 93.1% respectively. By removal of patients who reacted to band 31kDa but tested negative for antibodies to recombinant OspA antigen, in-house IgG and IgM WB specificity increased to >97%. Based on these results, we conclude that the use of the two-strain IgG and IgM WB and in-house interpretation criteria significantly increased the combined sensitivity of the test without significant loss of specificity. In patients with indeterminate WB results, a confirmation test with recombinant OspA is recommended.
Antibodies to the OspA antigen banding at 31kDa is present in vaccinated patients and in late stage Lyme disease [28,29]. A large number of serum samples from patients with symptoms of Lyme disease have only bands at 31kDa and 41kDa on either IgG or IgM WB. We reviewed results of Osp A confirmation test results performed on 500 patients with bands 31 and 41kDa on IgG and/or IgM WBs. About 50% of the patients were positive by the Osp A confirmation test. The negative patient samples probably had cross-reacting antibodies to a non-specific BB protein that co-migrates with Osp A at 31kDa. While the truly positive samples would be missed if band 31kDa is not included, the confirmation test was able to resolve a large number of false-positive results. We also observed that 30% of the patients with IgM antibodies to EBV had band 93kDa present with or without band 31kDa on the IgM WB. Removal of band 93kDa from IgM WB interpretive criteria did not affect sensitivity of IgM WB. Thus, the interpretive criteria for Lyme WB have been changed. The in-house WB is considered positive if two bands from the following six bands are present: 23, 31,34, 39, 41 and 93kDa, with the following exception: indeterminate if only bands 31 and 41kDa or 31 and 93kDa are present; and IgM WB is considered negative if only bands 41 and 93kDa are present.