Diagnostic challenges: lymphotropic sero-"questionables".

During a sero-survey for lymphotropic retroviruses, seven screening tests were performed for the three lymphotropic retroviruses of relevance in Djibouti, East Africa (HIV-1, HIV-2 and HTLV-1). Of the 82 subjects whose sera reacted in at least one retroviral screening assay, about one third could be followed, and their sera were re-examined after a 5-month interval, and then after an additional 3-month interval. Six selected individuals are reported here, whose retroviral serologies presented important and often unexplained changes over an eight-month period. The six cases summarize prototypic situations and present serological results in a style appropriate to stimulate thought on the significance and interpretation of lymphotropic viral serologies. Each case study is followed by a set of questions that formulate pertinent serological concepts.