Host determinants in HIV infection and disease part 1: Cellular and humoral immune responses

The course of HIV infection varies widely among individuals. Long-term nonp rogressors or slow progressors may remain asymptomatic and have normal CD4 counts despite more than a decade of untreated HIV infection, In contrast, rapid progressors develop AIDS within 5 years. In addition, some persons re main uninfected despite repeated exposure to HIV, Immunologic and genetic s tudies of long-term nonprogressors and exposed yet uninfected persons, as w ell as data from studies of primary HIV infection, have helped to elucidate the mechanisms by which some persons are protected from HIV acquisition or have slow rates of disease progression, This review (the first of two part s) describes what is currently known about host factors in HIV-1 infection. Studies for inclusion were identified by a systematic search of PubMed for English-language literature published from 1988 through June 2000. Abstrac ts of presentations at major meetings convened in 2000 were also included i f appropriate. Growing evidence suggests a crucial role of cytotoxic T cell s and T-helper cells in controlling viremia, slowing disease progression, a nd perhaps preventing establishment of infection. Humoral and mucosal immun ity, soluble inhibitory factors, the cytokine milieu, and concomitant infec tions also affect outcome. Genetic host factors, such as inheritance of mut ant chemokine receptors or certain HLA types, affect susceptibility to infe ction and subsequent clinical course. The role of cellular and humoral immu nity, mucosal immunity, and other local factors in determining the course o f HIV infection is discussed.