Inability of enzyme immunoassays to discriminate between infections with herpes simplex virus types 1 and 2.

OBJECTIVE

To determine the accuracy of three commercial enzyme immunoassays in detecting and subtyping antibodies to herpes simplex virus type 1 or 2.

DESIGN

Cross-sectional.

SETTING

Referral medical center.

PATIENTS

Ninety patients with culture-positive lesions caused by infection with herpes simplex virus type 1 or 2. The results of Western blot and glycoprotein G immunodot enzyme assays showed that an additional 53 patients had subclinical herpes simplex virus 2 infection, that another 20 patients had subclinical herpes simplex virus type 1 infection, and that 23 patients were seronegative.

MEASUREMENTS

Three commercial enzyme immunoassays were used to determine herpes simplex virus antibody subtypes.

MAIN RESULTS

All three commercial assays performed poorly in all patient groups (except in patients who were seronegative for herpes simplex virus). Among the 40 patients with a first episode of genital herpes, seroconversion to the appropriate viral type was shown by the three assays in only 33%, 55%, and 75% of cases. Among patients with recurrent genital herpes, the three commercial assays identified more than 90% of patients with only herpes simplex virus type 2 antibodies but failed to identify herpes simplex virus type 2 infections in 58% to 76% of patients with antibodies to both virus subtypes. The three assays correctly identified only 55%, 75%, and 85% of the 53 "silent carriers" of herpes simplex virus type 2. Overall, the three enzyme immunoassays detected herpes simplex virus type 2 antibodies in 60%, 62%, and 93% of patients with subtype 2 infections and falsely detected type 2 antibodies in 8%, 27%, and 49% of patients with type 1 infections.

CONCLUSION

Currently licensed enzyme immunoassays give inaccurate or misleading results about the correct herpes simplex virus infecting subtype.