Those genes whose expression is altered by immunosuppressive drug treatment may play an important role in ocular HSV-1 recurrence. Changes in gene expression in the prostaglandin pathway, a transcription factor, and an enzyme in the cell cycle are considered of special importance for HSV-1 reactivation by immunosuppression. Altered gene expression at 6 and 24 hours after heat stress was different from previously reported changes in gene expression 1 hour after hyperthermia in HSV-1 latently infected mice.

Real-time PCR quantitated HSV genome in the cornea even at a quiescent phase of infection. HSV genome was detected in the corneas and scleras without a past history of herpetic keratitis by this method.

Real-time PCR is a useful method for quantifying HSV DNA in tear samples from patients with herpetic keratitis. Using this method, we demonstrate that HSV reproduction occurs in persistent epithelial defect and disciform stromal keratitis.

Herpetic eye diseases exhibit various clinical manifestations making a diagnosis difficult in some patients. We quantitated herpes simplex virus (HSV) genomes in the tear fluid and aqueous humor obtained from patients with various herpetic eye diseases by real time PCR. The resulting amounts of HSV-DNA in herpetic epithelial keratitis (HEK), herpetic stromal keratitis (HSK) in active phase, and persistent epithelial defects (PED) were 3.9 x 10(6) copies (detection rate, 81.1%), 8.9 x 10(5) copies (detection rate, 59.1%), and 9.2 x 10(4) copies (detection rate, 88.9%), respectively. In the tear samples obtained from quiescent phase of HSK and endotheliitis, no HSV-DNA was detected. In the aqueous humor of uveitis patients, HSV-DNA was found 3.8 x 10(5) copies/ml (detection rate, 16.7%). Previous studies have shown that active viral replication is not directly related to the persistent epithelial defects and progressive HSK. A relatively high level of HSV-DNA, however, was detected in the tear samples of these two disease forms, although the source of the viral replication was not identified. These findings might bring new ideas about the mechanisms of developments in HSK and PED.