Intracytoplasmic vacuoles in cervical smears: relationship to chlamydial inclusions--morphology, mucin histochemistry, and immunocytochemistry.

Cytomorphology, mucin stains, and immunocytochemistry were used to determine the characteristics of intracytoplasmic vacuoles in cervical smears and their relationship to chlamydial infections. Three study groups were examined: A) cervical smears containing intracytoplasmic vacuoles suggesting chlamydial infection: B) cervical smears from patients known to be either culture positive or culture negative for chlamydia; and C) control smears of chlamydia-infected McCoy cell cultures. Forty-nine smears containing vacuoles suspected of being chlamydial inclusions were studied. In 21 of 31 smears the vacuoles were shown by histochemistry to contain mucin. Immunoperoxidase staining performed on the remaining 18 smears revealed only two vacuoles to be chlamydial inclusions. Of 38 smears from chlamydia-culture-positive patients, only 4 showed chlamydial inclusions by immunoperoxidase methods. Of 30 smears from chlamydia-culture-negative patients, none were positive by immunoperoxidase staining. The "nebular body" of Shiina appears to be the most specific cytomorphologic evidence of chlamydial infection in cervical smears, but distinction from mucin vacuoles and other nonspecific vacuoles is difficult. The immunoperoxidase technique is unlikely to be useful in diagnosis in cervical smears unless samples are specifically obtained from the endocervical canal by endocervical brushing.