Recombinant rmIFNα induces a transient increase of ISGs in vivo. A heat map of the fold change in gene expression relative to day −21 of treatment as measured from mRNA extracted from PBMCs of SIV-infected SMs (n = 8) treated longitudinally with recombinant rmIFNα2 and hybridized to Affymetrix Rhesus Arrays shows a significant up-regulation of ISGs during treatment. Genes with differential expression over time (P < .0006 by ANOVA) and documented function as ISGs are shown on the left; P values are shown on the right. Individual colored panels represent the average fold change. The color scale is indicated at bottom.