Conjunctival impression cytology for vitamin A deficiency in the presence of infectious trachoma

摘要

BACKGROUND/AIMS—Increased morbidity and mortality from a number of infectious diseases have been associated with vitamin A deficiency. Trachoma and vitamin A deficiency are both important causes of blindness in Nepal. The purpose of this study was to determine the association between the diagnosis of vitamin A deficiency by conjunctival impression cytology and the diagnosis of infectious trachoma by the polymerase chain reaction (PCR) in the Lumbini zone of Nepal.
METHODS—70 children under the age of 11 in a rural village in the Lumbini zone were examined for clinical evidence of active trachoma. The conjunctiva of each child was tested for ocular Chlamydia trachomatis infection using PCR, and for loss of goblet cells (a sign of subclinical vitamin A deficiency) using conjunctival impression cytology.
RESULTS—The presence of infectious trachoma was associated with the loss of goblet cells on conjunctival impression cytology (p=0.02). This relation was present and significant even when adjusted for age (p=0.05) and degree of inflammation (p=0.02). In fact, even subclinical infection with chlamydia was associated with an abnormal conjunctival impression cytology (p=0.02).
CONCLUSIONS—Children with infectious trachoma are significantly more likely to have an abnormal conjunctival impression cytology, even if the infection is subclinical. Thus, the diagnosis of vitamin A deficiency from conjunctival impression cytology alone should be made with some caution in areas with endemic trachoma. Further studies will be needed to determine the cause of this association.

Keywords: trachoma; vitamin A; impression cytology; chlamydia