IMPACT OF STRAIN HETEROGENEITY ON LYME-DISEASE SEROLOGY IN EUROPE - COMPARISON OF ENZYME-LINKED IMMUNOSORBENT ASSAYS USING DIFFERENT SPECIES OF BORRELIA-BURGDORFERI SENSU-LATO

For the standardization of serological tests for Lyme borreliosis (LB) in Europe, the influence of the heterogeneity of Borrelia burgdorferi sensu late must be assessed in detail. For this study four immunoglob ulin M (IgM) and IgG enzyme-linked immunosorbent assays (ELISAs) with octyl-P-D-glucopyranoside extracts of strains PK0 (Borrelia afzelii), PBi (Borrelia garinii), and PKa2 and B31 (both B. burgdorferi sensu st ricto) were compared. Strains PK0, PBi, and PKa2 at the passages used for antigen preparations abundantly expressed outer surface protein C (OspC), whereas strain B31 at the passage used for antigen preparation did not express OspC. Sera (all from Germany) from 222 patients with clinically defined LB of ail stages, 133 blood donors, and 458 forest workers were tested. None of the forest workers had symptoms consisten t with LB at the time that the samples were collected. For IgM tests, receiver operating characteristic curves demonstrated that discriminat ion between sera from patients end blood donors was best with strain P K0 and worst with strain B31. The discriminatory abilities of the four IgG ELISAs were similar in a diagnostically reasonable specificity ra nge (90 to 100%). More than 20% of the sera from forest workers reacte d strongly in the PK0 IgG ELISA (optical density value, >1.5; other as says, less than 8%). Western blots of the sera with the most discrepan t ELISA results revealed almost exclusive reactivity with p17. This hi ghly immunogenic antigen is only expressed by strain PK0. This observa tion might be important for the development of assays enabling discrim ination between asymptomatic or previous infection and active disease.