The uterine cervix--a new member of the family of immunologically exceptional sites?

As a bystander effect, immune responses against infectious organisms can damage normal cells. Immune privilege can protect such endangered tissues from immune destruction. One example is the eye where potentially devastating inflammatory reactions are prevented by active, counter-regulating processes that prevent lymphocyte activation. Recent epidemiological data from transplant patients in Sweden showed, surprisingly, that the frequency of cervical cancers did not increase in organ transplant recipients, in contrast to cancers of the vagina, vulva and anus. The same subtypes of HPV are known to be involved in the genesis of all these tumors. The immune surveillance mechanisms known to antagonize the outgrowth of virally-associated neoplasms would have been expected to affect them all. The special case of cervical carcinomas may reflect a site-specific immune privilege that could have evolved to protect the integrity of the reproductive function.