Comparison of immunocytochemistry and in situ hybridization in the cytodiagnosis of genital herpetic infection.

Over a 62-month period, 53 patients were found to have cervicovaginal smears that contained cells consistent with, or equivocal cells for, a herpes simplex virus (HSV) infection. The Papanicolaou-destained smears from these cases were restrained in situ hybridization (ISH) with a biotinylated cloned DNA probe and immunocytochemistry (ICC) assay and were compared for the detection of HSV in cervicovaginal smears by two methods. Cytological findings classified the 53 slides into two groups, i.e., cytologically herpes positive (33 patients) and equivocal cases (20 patients). Each group was subdivided into two groups: group A was confirmed by ICC, and group B was confirmed by ISH technique. Of the 33 cellular samples containing cells considered to be consistent with a herpes infection, 15 (88%) of 17 were positive by means of ICC technique (group A), 6 (43%) of 14 were positive by ISH technique (group B). Of the 20 smears showing equivocal cell changes thought unlikely to be caused by an HSV infection, 6 (60%) of 10 were positive by ICC (group A), 2 (29%) of 7 were positive by ISH (group B). With the ISH technique, five smears showed dislodged cells from glass slides due to enzyme treatment and denaturation. The results revealed that the ICC technique is a rapid and reliable procedure and thus recommended for routine diagnosis of HSV infection. Moreover, ICC is easier to perform and interpret and is less expensive than ISH. Therefore, the ICC may be preferable to ISH for detecting HSV in routine Papanicolaou diagnostic work.