Objective. To describe the clinical characteristics of intrauterine infection with lymphocytic choriomeningitis (LCM) virus, an uncommonly recognized cause of congenital viral infection. Patients. Three infants born in the midwestern United States in 1994 and 1995 with clinical features and serologic studies consistent with congenital LCM virus infection and cases of congenital infection identified by review of the medical literature between 1955 and 1996. Results. Twenty-six infants with serologically confirmed congenital LCM virus infection were identified. Twenty-two infants were products of term gestations, and birth weights ranged from 2384 to 4400 g (median, 3520 g). Ocular abnormalities, macrocephaly, or microcephaly were the most commonly identified neonatal features. Twenty-one infants (88%) had chorioretinopathy, 10 (43%) had macrocephaly (head circumference >90th percentile) at birth, and 3 (13%) were microcephalic (head circumference <10th percentile). Macrocephaly and hydrocephalus developed postnatally in one of the latter infants. Hydrocephalus or intracranial calcifications were documented in five infants by computed tomography or magnetic resonance imaging. Nine infants (35%) died, and 10 (63%) of the 16 reported survivors had severe neurologic sequelae, consisting of spastic quadriparesis, seizures, visual loss, or mental retardation. One-half of the mothers reported illnesses compatible with LCM virus infection, and 25% reported exposures to rodents during their pregnancies. Conclusions. These cases suggest that congenital LCM virus infection could be an underrecognized cause of congenital infection among infants born in the United States. Because of the clinical similarities of these congenital infections, cases of congenital LCM virus infection can be confused with infections with cytomegalovirus or Toxoplasma gondii.

Objective: Varicella-zoster virus (VZV) infection may trigger the inflammatory cascade that characterizes giant cell arteritis (GCA). Methods: Formalin-fixed, paraffin-embedded GCA-positive temporal artery (TA) biopsies (50 sections/TA) including adjacent skeletal muscle and normal TAs obtained postmortem from subjects >50 years of age were examined by immunohistochemistry for presence and distribution of VZV antigen and by ultrastructural examination for virions. Adjacent regions were examined by hematoxylin & eosin staining. VZV antigen–positive slides were analyzed by PCR for VZV DNA. Results: VZV antigen was found in 61/82 (74%) GCA-positive TAs compared with 1/13 (8%) normal TAs (p < 0.0001, relative risk 9.67, 95% confidence interval 1.46, 63.69). Most GCA-positive TAs contained viral antigen in skip areas. VZV antigen was present mostly in adventitia, followed by media and intima. VZV antigen was found in 12/32 (38%) skeletal muscles adjacent to VZV antigen–positive TAs. Despite formalin fixation, VZV DNA was detected in 18/45 (40%) GCA-positive VZV antigen–positive TAs, in 6/10 (60%) VZV antigen–positive skeletal muscles, and in one VZV antigen–positive normal TA. Varicella-zoster virions were found in a GCA-positive TA. In sections adjacent to those containing VZV, GCA pathology was seen in 89% of GCA-positive TAs but in none of 18 adjacent sections from normal TAs. Conclusions: Most GCA-positive TAs contained VZV in skip areas that correlated with adjacent GCA pathology, supporting the hypothesis that VZV triggers GCA immunopathology. Antiviral treatment may confer additional benefit to patients with GCA treated with corticosteroids, although the optimal antiviral regimen remains to be determined.

Varicella-zoster virus (VZV) is an alphaherpesvirus with the characteristic neurotropism of this group, but VZV also infects T cells productively and downregulates major histocompatibility complex (MHC) class I expression on infected T cells, as shown in the SCID-hu mouse model. T-cell tropism is likely to be critical for the cell-associated viremia associated with primary VZV infection. In these experiments, we found that VZV infects human tonsillar CD4⁺T cells in culture, with 15 to 25% being positive for VZV proteins as detected by polyclonal anti-VZV immunoglobulin G (IgG) staining and monitored by flow cytometry analysis. RNA transcripts for VZV gE, a late gene product, were detected in T-cell populations that expressed VZV surface proteins, but not in the VZV-negative cell fraction. Exposure to phorbol myristate acetate resulted in an increase in VZV-positive T cells, indicating that viral DNA was present within these cells and that VZV gene expression could be induced by T-cell activation. By immune scanning electron microscopy, VZV virions were detected in abundance on the surfaces of infected tonsillar T cells. The predominant CD4⁺T-lymphocyte subpopulations that became infected were activated CD69⁺T cells with the CD45RA⁻memory phenotype. Subsets of CD4⁺T cells that expressed skin homing markers, cutaneous leukocyte antigen, and chemokine receptor 4 were also infected with VZV. By chemotaxis assay, VZV-infected T cells migrated to SDF-1, demonstrating that skin migratory function was intact despite VZV infection. The susceptibility of tonsil T cells to VZV suggests that these cells may be important targets during the initial VZV infection of upper respiratory tract sites. Viral transfer to migrating T cells in the tonsils may facilitate cell-associated viremia, and preferential infection of CD4 T cells that express skin homing markers may enhance VZV transport to cutaneous sites of replication.

Varicella-zoster virus (VZV) is a remarkably stable virus that until recently was thought to exhibit near-universal genetic homogeneity among circulating wild-type strains. In recent years, the expanding knowledge of VZV genetics has led to a number of groups proposing sequence-based typing schemes, but no study has yet examined the relationships between VZV genotypes at a full-genome level. A central hypothesis of this study is that VZV has coevolved with humankind. In this study, 11 additional full VZV genomic sequences are presented, bringing the current number of complete genomic sequences publicly available to 18. The full-genome alignment contained strains representing four distinct clades, but the possibility exists that a fifth clade comprised of African and Asian-like isolates was not represented. A consolidated VZV genotyping scheme employing the origin-associated region between reiteration region R4 and open reading frames (ORFs) 63 and 70 is described, one which accurately categorizes strains into one of four clades related to the geographic origin of the isolates. The full-genome alignment also provided evidence for recombination having occurred between the major circulating VZV clades. One Canadian clinical isolate was primarily Asian-like in origin, with most of the genome showing strong sequence identity to the Japanese-like clade B, with the exceptions being two putative recombination regions, located in ORFs 14 to 17 and ORFs 22 to 26, which showed clear similarity to the European/North American clade A. The very low rate of single-nucleotide polymorphisms scattered across the genome made full-genome sequencing the only definitive method for identifying specific VZV recombination events.