Prognostic value of cerebrospinal fluid cytokine changes in herpes simplex virus encephalitis.

A recent trial suggested that corticosteroid was beneficial in herpes simplex virus encephalitis (HSVE), but that precise role remains unclear. We assessed the differences of cerebrospinal fluid (CSF) cytokine changes between different outcomes and between patients with and without corticosteroid administration at the acute stage of HSVE. Interleukin (IL)-1beta, IL-2, IL-6, IL-10, interferon (IFN)-gamma, and tumor necrosis factor-alpha were measured in 56 serial CSFs taken from 20 adult HSVE patients. Their outcomes were poor in 7 and good in 13 patients, and corticosteroid was administered in 10. The differences in the initial and maximum cytokine values were assessed among the different outcomes. The decline rate of cytokine values between the initial and second CSF samples was also assessed between patients with and without corticosteroid. The initial IFN-gamma and maximum IL-6 with a poor outcome were higher than those with a good outcome (p=0.019 for IFN-gamma and p=0.013 for IL-6). The decline rate of IL-6 in patients with corticosteroid was higher than that without corticosteroid (p=0.034). The initial IFN-gamma and maximum IL-6 CSF values represented prognostic biomarkers in HSVE. One pharmacological mechanism related to corticosteroid in HSVE is apparently inhibition of pro-inflammatory cytokines such as IL-6.

The herpes simplex virus type 1 BgKL variant, unlike the BgOL variant, shows a higher association with orolabial infection than with infections at other sites, supporting the variant-dispersion-replacement hypothesis.

The identification and geographic distribution of the herpes simplex virus type 1 (HSV-1) BglII restriction fragment length polymorphism (RFLP) variants named BgK(L) and BgO(L) in clinical isolates from orolabial and cutaneous sites were described in our previous reports, in which the dispersion and replacement of HSV-1 variants were proposed. The base substitution sites deduced from the BgK(L) multiple RFLP variations were mapped to the U(L)12 (DNase), R(L)2 (alpha0 transactivator), and latency-associated transcript genes in the present study. The results show that the relative frequencies (RFs) of BgK(L) are significantly higher in orolabial and cutaneous HSV-1 infections than in ocular infections. For the BgO(L) variant, the opposite was found; i.e., the RF of BgO(L) was significantly lower in orolabial and cutaneous infections than in ocular infections. No significant differences in the RFs of non-BgK(L):non-BgO(L) isolates were observed. The ratio of the BgK(L) RF to the BgO(L) RF was much higher for the orolabial and cutaneous infection groups than for the ocular infection group, whereas the BgK(L) RF-to-non-BgK(L):non-BgO(L) RF ratios for the former groups were slightly higher than those for the latter group. The higher efficiency of orolabial and cutaneous infections caused by BgK(L) compared to the efficiency of infections caused by BgO(L) allows BgK(L) to spread more efficiently in human populations and to displace BgO(L), because the mouth and lips are the most common HSV-1 infection sites in children. The present study supports our HSV-1 dispersion-and-replacement hypothesis and suggests that HSV-1, the latency-reactivation of which allows variants to accumulate in human populations, has evolved under competitive conditions, providing a new perspective on the polymorphism or variation of HSV-1.

Intradermal doxorubicin reduces ganglionic reactivation of latent herpes simplex virus in mice after pretreatment with hypertonic saline.

Recurrent lesions from herpes simplex virus (HSV) occur after reactivation of latent HSV in neurons of sensory ganglion, axonal transport of reactivated virus, and HSV replication on the skin. A potential treatment strategy is to inject epithelial sites of frequent recurrences with anti-viral or cytotoxic agents that are taken up by nerve terminals and transported by axoplasmic flow to latently infected ganglionic neurons. Doxorubicin is transported by nerves and destroys the corresponding nerve cell bodies, but earlier attempts in HSV animal models required intraneural injection to eliminate HSV infection and this treatment destroyed the nerve and large portions of the ganglion. The present study used intradermal doxorubicin in latently infected mice that had been inoculated with HSV by the lip route and passively immunized at the time of inoculation. As found previously, doxorubicin injection in the lip 2 or more months after HSV inoculation did not eliminate HSV latency as evaluated by recovery of virus from trigeminal ganglionic explants. However, when hypertonic saline was injected in the same site 24 hr prior to doxorubicin, there was a 55% reduction of positive ganglionic explant cultures. Edema from the hypertonic saline may increase access of doxorubicin to nerve terminals. This technique with hypertonic saline, which has also been used to enhance virulence of HSV skin innoculation, may have general application of increasing axoplasmic transport of drugs or biologicals. Skin toxicity may preclude doxorubicin use for HSV recurrences in patients; however, the results of this study support the concept of anti-HSV treatment via retrograde axoplasmic transport.