Varicella zoster virus deoxythymidine kinase is present in serum before the onset of varicella

Varicella-zoster virus: a re-emerging infection

Varicella-zoster virus (VZV) causes chickenpox (varicella), becomes latent in cranial nerve and dorsal root ganglia, and can reactivate many years later to produce shingles (zoster) and postherpetic neuralgia (PHN). Elderly and immunocompromised individuals are also at risk for complications of VZV reactivation involving the central nervous system (CNS), including myelitis, large-vessel encephalitis/granulomatous arteritis, small-vessel encephalitis, meningoencephalitis, and ventriculitis. Peripheral nervous system (PNS) complications range from zoster and postherpetic neuralgia to postinfectious polyneuritis (Guillain-Barre syndrome, GBS). These complications can occur with or without cutaneous manifestations. An increase in elderly and immunocompromised individuals will likely result in a higher prevalence of these conditions; therefore, VZV can be seen as a "re-emerging" infection of the early twenty-first century. In this review, we summarize our experience and the existing literature on CNS and PNS complications of VZV reactivation. Special attention is paid to reports of complications without rash, as these entities are more difficult to diagnose.

Dose-dependent effects of oral acyclovir in the incubation period of varicella

Dose of acyclovir (ACV) and clinical features of varicella were evaluated in 65 household contacts (0.8-9 y) who received oral ACV (5-80 mg/kg daily in four divided doses) during the latter half of the incubation period of varicella. The severity of the disease was compared with that of 23 children who did not receive ACV. Infection was confirmed by a fluorescent antibody to membrane antigen assay. The antibody titers and the rate of apparent infection increased as the dose of ACV administered decreased. The number of skin lesions in patients who received ACV was significantly reduced when compared to the control group. These data suggest dose-dependence of ACV for modification of varicella during secondary viremia in the incubation of the disease.

Effect of oral acyclovir against primary and secondary viraemia in incubation period of varicella

The effect of oral acyclovir (approximately 40 mg/kg daily in four divided doses) against primary and secondary viraemia of varicella zoster virus (VZV) was examined in 27 children susceptible to VZV who were exposed to the virus in their families and their clinical features were compared with those of 19 non-treated subjects. The infection was confirmed by a fluorescent antibody to membrane antigen assay in 11 (85%) of 13 children who received acyclovir for the first seven days after exposure to VZV and in 11 (79%) of 14 who received acyclovir for the next seven days. The geometric mean antibody titre of the former group was significantly higher than that of the latter group. Varicella developed in 10 (91%) and was subclinical in one (9%) in the former group, whereas a very mild disease occurred in three (27%) and was subclinical in eight (73%) in the latter group. The severity of varicella was significantly greater in the former group than that in the latter group. On the other hand, all of the control group developed typical varicella and their clinical features were more severe than those of the acyclovir administered group. These data indicate that oral acyclovir more effectively inhibits replication of VZV in secondary viraemia than that of the primary viraemia.

Thymidine kinase: a tumor marker with prognostic value for non-Hodgkin's lymphoma and a broad range of potential clinical applications

Thymidine kinase (TK) is a cellular enzyme which is involved in a "salvage pathway" of DNA synthesis. It is activated in the G1/S phase of the cell cycle, and its activity has been shown to correlate with the proliferative activity of tumor cells. Additionally, certain viruses are able to induce cellular TK production and activity. Clinical studies have reported elevated serum TK levels in a variety of neoplasias. The majority of these studies concerned hematologic malignancies. TK seems to be a useful marker in non-Hodgkin's lymphoma, where it correlates with clinical staging and provides significant prognostic information on (progression-free) survival. Preliminary results in acute myeloid leukemia indicate that pretreatment serum TK values may predict the response to the first induction chemotherapy. Moreover, serum TK appears to have some clinical value in such solid tumors as prostate cancer, breast cancer, and small-cell lung cancer, whereas it is not a reliable marker of non-small-cell lung cancer and brain tumors.