HIV infection of a fetus from an infected mother has severe immunological implications because it destroys still immature immune system. The abnormalities observed are precocious in the infants. When the infection occurs in perinatal period, clinical and immunological manifestations can present themselves at the age of 2-5 years. Two patterns of HIV infection can be distinguished. Humoral immunodeficiency is present in a high proportion of patients and leads to repeated bacterial infections and progression of the disease. Immunoglobulin substitution therapy improves clinical manifestations and can help to avoid viral replication.