PRF1 and retinitis: Quantification of perforin mRNA levels within MCMV-infected eyes of mice with MAIDS administered PEG-IL-2 intramuscularly revealed a significant intraocular upregulation of perforin transcripts that correlated with a significant reduction in the frequency of MCMV retinitis from ~80% in untreated mice with MAIDS to 0% in PEG-IL-2-treated mice with MAIDS [58].