Kaposi sarcoma (KS) is an invasive angioproliferative inflammatory condition that occurs commonly in men infected with human immunodeficiency virus (HIV; see 609423). In the early stages of KS, lesions appear reactive and are stimulated to grow by the actions of inflammatory cytokines and growth factors. In the late stages of KS, a malignant phenotype that appears to be monoclonal can develop. Infection with human herpesvirus-8 (HHV-8), also known as KS-associated herpesvirus (KSHV), is necessary but not sufficient for KS development. Coinfection with HIV markedly increases the likelihood of KS development, and additional environmental, hormonal, and genetic cofactors likely contribute to its pathogenesis (summary by Foster et al., 2000). Suthaus et al. (2012) noted that HHV-8 is the etiologic agent not only of KS, but also of primary effusion lymphoma and plasma cell-type multicentric Castleman disease (MCD).

An abnormal reduction in numbers of all blood cell types (red blood cells, white blood cells, and platelets).

A type of hemolytic anemia in which the Coombs test is positive.

Failure of the immune system to protect the body adequately from infection, due to the absence or insufficiency of some component process or substance.

Abnormal increased size of the spleen.