Immunohistochemical investigations of genital ulcers caused by Haemophilus ducreyi.

ABSTRACT

PIP: Chancroid, the most prevalent form of genital ulcer disease in developing countries, increases the risk of HIV transmission. Use of monoclonal antibodies against leukocyte differentiation antigens enabled analysis of the composition of the inflammatory infiltrate of genital ulcers. In this study, biopsies of six genital ulcers caused by Haemophilus ducreyi were examined immunohistochemically. In each case, staining revealed a superficial necrotic layer of polymorphonuclear leukocytes with fibrin and erythrocytes at the base of the ulcer, a middle layer of the edematous inflammatory dermis with prominent blood vessels and vascular thrombi, and a deep layer of an inflammatory infiltrate of plasma cells and lymphocytes. The lymphocytic infiltrate of chancroid ulcers consisted of both B- and T-lymphocytes and showed a cluster-like formation. B-lymphocytes were preferentially localized perivascularly in the middle layer, while T-lymphocytes tended to be located in the deep layer of the inflamed edematous tissue. These findings provide further evidence of the importance of the involvement of T-cells in the local immune clearance of H. ducreyi. Future studies should investigate lymphocyte secretions detected in genital ulcers caused by H. ducreyi to gain more information on the role of the cellular immune mechanisms in the disease.