Improvement of Lyme borreliosis serodiagnosis by a newly developed recombinant immunoglobulin G (IgG) and IgM line immunoblot assay and addition of VlsE and DbpA homologues

Abstract

We developed and evaluated a recombinant Borrelia line immunoblot assay based on 18 homologues of seven different antigens, i.e., p100, p58, p41i, BmpA, VlsE, OspC, and DbpA. Each recombinant antigen can be detected separately and is distinct even from homologues with identical molecular weights. This blot was compared to the recently described recombinant Borrelia Western immunoblot assay (U. Schulte-Spechtel, G. Lehnert, G. Liegl, V. Fingerle, C. Heimerl, B. J. Johnson, and B. Wilske, J. Clin. Microbiol. 41:1299-1303, 2003). To verify sensitivity and specificity, both blots were evaluated for reactivity with Borrelia-specific immunoglobulin G (IgG) and IgM antibodies with 85 sera from patients with different manifestations of Lyme borreliosis and 110 controls. According to European interpretation criteria for Borrelia Western blots, which define a serum as positive when it recognizes at least two bands, sensitivity increased significantly from 70.6% (Western blot) to 84.7% (line blot) for IgG (P = 0.042) and from 40.0% (Western blot) to 73.8% (line blot) for IgM (P < 0.005). The increased sensitivity for IgG detection is due to the new line blot technique, whereas the improvement in detection of IgM is mainly achieved through incorporation of the additional antigens. Notably, the recombinant VlsE of Borrelia garinii strain PBi displayed the highest sensitivity of all antigens tested for IgG detection and is also one of the most useful antigens for IgM. Due to its excellent sensitivity and specificity combined with ease of evaluation, this line immunoblot assay offers a useful improvement in serodiagnosis of Lyme borreliosis.

FIG. 1.

Representative IgG line immunoblots of patient and control sera. Strains belong to the following species: B31 and PKa2 to B. burgdorferi sensu stricto, PKo to B. afzelii, PBr to B. garinii OspA type 3, PBi to B. garinii OspA type 4, and 20047 to B. garinii unknown OspA type. Sera were obtained from patients with EM, early neuroborreliosis (NB), acrodermatitis chronica atrophicans or Lyme arthritis (late LB), and controls. *, additional antigen on the IgG line blot.

FIG. 2.

Representative IgM line immunoblots of patient and control sera. Strains belong to the following species: B31 and PKa2 to B. burgdorferi sensu stricto, PKo to B. afzelii, PBr to B. garinii OspA type 3, PBi to B. garinii OspA type 4, and 20047 to B. garinii unknown OspA type. Sera were obtained from patients with EM, early neuroborreliosis (NB), acrodermatitis chronica atrophicans or Lyme arthritis (late LB), and controls. [p100], not included in the valuation of the IgM blot results (note p100 reactivity of control sera); *, additional antigen on the IgM line blot.