Human immunodeficiency virus type 1 RNA populations in faeces with higher homology to intestinal populations than to blood populations.

To determine whether human immunodeficiency virus type 1 (HIV-1) in faeces is representative of the HIV-1 population in intestinal tissue, we studied HIV-1 V3 variation in faeces, intestinal biopsies and serum from two individuals. Phylogenic analysis of HIV-1 V3-coding RNA in faeces from one individual showed three distinct genotypes. Viruses belonging to all three genotypes were also present in sigmoidal tissue and in serum. Jejunal tissue contained two of these three genotypes. Analysis of the V3-coding RNA in faeces of the other individual showed five distinct genotypes. One of these genotypes was present in all specimens from this individual. Besides this shared genotype, jejunal tissue and serum contained sequences belonging to one other genotype. In addition, one of the other three V3 variants was detected in sigmoidal tissue. For both persons the shared HIV-1 RNA genotypes in faeces and serum displayed a distinctly different frequency distribution. In one individual, the genotype which was detected in a majority of the clones in faeces (59%) and as a minority in serum (11%), was the most abundant genotype in jejunal and sigmoidal tissue (61% and 80%, respectively). For the other individual the genotype that was present in faeces in a significant number of clones (43%) was detected in serum as a minority (8%), whereas this genotype composed 47% of the clones isolated from jejunal tissue. Taken together these data suggest that faeces contain HIV-1 sequences that are derived from local HIV-1 replication in intestinal tissue.