Pathogenesis of pelvic inflammatory disease. What are the questions?
P. A. Rice and J. Schachter
Maxwell Finland Laboratory for Infectious Diseases, Boston City Hospital, MA 02118.
Pelvic inflammatory disease is usually caused by Chlamydia trachomatis or
Neisseria gonorrhoeae. Chlamydiae and gonococci are primary pathogens of
the cervix and often ascend. Resultant damage to the cervix may permit
organisms to move upward, but this mechanism of action is not well
understood. Puberty and hormones, particularly oral contraceptives, may
enhance chlamydial infection, but the mechanisms and likelihood of spread
to the upper tract are ill defined. Upper tract infection with C
trachomatis involves an acute phase, characterized by an influx of
polymorphonuclear leukocytes and a chronic or persistent phase
characterized by the presence of mononuclear cells (delayed
hypersensitivity). Gonococci invade nonciliated epithelial cells, but are
toxic to ciliated cells, due to elaborated lipooligosaccharides and
peptidoglycan. Certain gonococci stimulate chemotaxis of polymorphonuclear
leukocytes whose release of toxic metabolites may damage tissue. The
immunologic mechanisms that permit specific host responses to these two
organisms are now being elucidated and should receive more attention by
researchers.
