The convergent distribution of the Human Immunodeficiency Virus (HIV) and helminth infections has led to the suggestion that infection with helminths exacerbates the HIV epidemic in developing countries. A large body of suggestive evidence in support of this hypothesis has been accumulated in many countries over the past two decades. Although 57% of the South African population lives in poverty and carry the highest burden of both HIV and helmith infection, the disease interactions are under-researched in South Africa. This book details work undertaken in Khayelitsha, an informal settlement in the Western Cape Province of South Africa, where both HIV and intestinal helminth infections are highly prevalent. The immune profile of adults who are either singly-or dually- infected with HIV and Ascaris lumbricoides and/or Trichuris trichuria, plus non-infected HIV negative controls, is described in relation to the ability to control HIV infection. Four different phenotypes that respond differently to helminth infection are described and immunological profile related to HIV pathogenesis analysed.