The influence of bacterial lysate [see text]PC-19 on the mucosal immunity of children with HIV infection was evaluated. The action of this topical immunomodulator was found to increase the synthesis of sIgA, which was indirectly reflected in a rise of the local immunity of the upper respiratory ways, preventing the aggravation of the chronic focal infection and the main disease. It should be pointed out that in a group of HIV-infected children and adolescents with an initially high level of salivary IgG the prescription of preparation [see text]PC-19 led to its considerable decrease. A decrease in the level of IgG and a rise in the content of sIgA in saliva under the action of the preparation correlated with a decrease in inflammatory changes in the nasopharyngeal mucosa. On the basis of results obtained in this study additions to the algorithm of the prophylactic medical observation of children and adolescents with HIV infection have been developed.