HIV-infected individuals on long-term antiretroviral therapy are at higher risk for ocular disease.

Introduction of antiretroviral therapy (ART) has dramatically reduced the incidence of infectious ocular diseases in human immunodeficiency virus (HIV)-infected individuals. However, the effects of long-term ART and chronic HIV infection on the eye are ill-defined. This study determined the occurrence and severity of ocular diseases among 342 participants in a rural South African setting: HIV-naïve (n = 105), HIV-infected ART-naïve (n = 16), HIV-infected on ART for 36 months (long-term ART; n = 165). More HIV-infected participants presented with an external eye condition, in particular blepharitis, than HIV-naïve individuals (18% vs. 7%; age-adjusted odds ratio (aOR) = 2·8, P < 0·05). Anterior segment conditions (particularly keratoconjunctivitis sicca and pterygium) were also more common (50% vs. 27%; aOR = 2·4; P < 0·01). Compared with individuals on short-term ART, participants receiving long-term ART were more likely to have clinically detectable cataract (57% vs. 38%; aOR = 2·2, P = 0·01) and posterior segment diseases, especially HIV retinopathy (30% vs. 11%; aOR = 3·4, P < 0·05). Finally, long-term ART was significantly associated with presence of HIV retinopathy (P < 0·01). These data implicate that ocular disease is more common and of more diverse etiology among HIV-infected individuals, especially those on long-term ART and suggest that regular ophthalmological monitoring of HIV-infected individuals on ART is warranted.

Clinical and corneal microbial profile of infectious keratitis in a high HIV prevalence setting in rural South Africa.

The purpose of this investigation was to determine the clinical and corneal microbial profile of infectious keratitis in a high human immunodeficiency virus (HIV) prevalence setting in rural South Africa. Data in this cross-sectional study were collected from patients presenting with symptoms of infectious keratitis (n = 46) at the ophthalmology outpatient department of three hospitals in rural South Africa. Corneal swabs were tested for herpes simplex virus type 1 (HSV-1) and 2 (HSV-2), varicella zoster virus (VZV) and adenovirus DNA by real-time polymerase chain reaction (PCR) and for bacteria and fungi by culture. Based on clinical history, disease characteristics and laboratory results, 29 (63 %) patients were diagnosed as viral keratitis, including 14 (48 %) viral keratitis cases complicated by bacterial superinfection, and 17 (37 %) as bacterial keratitis. VZV and HSV-1 DNA was detected in 11 (24 %) and 5 (11 %) corneal swabs, respectively. Among clinically defined viral keratitis cases, a negative viral swab was predominantly (93 %) observed in cases with subepithelial inflammation and was significantly associated with an increased duration of symptoms (p = 0.003). The majority of bacteria cultured were Gram-positive (24/35), including Staphylococcus epidermidis and S. aureus. Viral aetiology was significantly associated with a history of herpes zoster ophthalmicus (p < 0.001) and a trend was observed between viral aetiology and HIV infection (p = 0.06). Twenty-one (47 %) keratitis cases were complicated by anterior uveitis, of which 18 (86 %) were HIV-infected cases with viral keratitis. The data implicate a high prevalence of herpetic keratitis, in part complicated by bacterial superinfection and/or uveitis, in HIV-infected individuals presenting with infectious keratitis in rural South Africa.

CD4 T-cell memory responses to viral infections of humans show pronounced immunodominance independent of duration or viral persistence.

Little is known concerning immunodominance within the CD4 T-cell response to viral infections and its persistence into long-term memory. We tested CD4 T-cell reactivity against each viral protein in persons immunized with vaccinia virus (VV), either recently or more than 40 years ago, as a model self-limited viral infection. Similar tests were done with persons with herpes simplex virus 1 (HSV-1) infection as a model chronic infection. We used an indirect method capable of counting the CD4 T cells in blood reactive with each individual viral protein. Each person had a clear CD4 T-cell dominance hierarchy. The top four open reading frames accounted for about 40% of CD4 virus-specific T cells. Early and long-term memory CD4 T-cell responses to vaccinia virus were mathematically indistinguishable for antigen breadth and immunodominance. Despite the chronic intermittent presence of HSV-1 antigen, the CD4 T-cell dominance and diversity patterns for HSV-1 were identical to those observed for vaccinia virus. The immunodominant CD4 T-cell antigens included both long proteins abundantly present in virions and shorter, nonstructural proteins. Limited epitope level and direct ex vivo data were also consistent with pronounced CD4 T-cell immunodominance. We conclude that human memory CD4 T-cell responses show a pattern of pronounced immunodominance for both chronic and self-limited viral infections and that this pattern can persist over several decades in the absence of antigen.

Quantification of viral DNA and liver enzymes in plasma improves early diagnosis and management of herpes simplex virus hepatitis.

Herpes simplex virus (HSV) hepatitis is a rare and potential life-threatening disease. The diagnosis of HSV hepatitis is hampered by its indifferent clinical presentation, which necessitates confirmatory laboratory data to identify HSV in the affected liver. However, liver biopsies are often contraindicated in the context of coagulopathy, are prone to sampling errors and have low sensitivity in mild HSV hepatitis cases. There is an unmet need for less invasive diagnostic tools. The diagnostic and therapeutic value of HSV DNA load and liver enzyme level kinetics was determined in five patients with HSV hepatitis and twenty disease controls with HSV-DNAemia without hepatitis. At time of hospitalization, patients with HSV hepatitis had a higher median (± interquartile range) HSV DNA load (6.0 × 10(6) ± 1.2 × 10(9)) compared to disease controls (171 ± 2845). Viral DNA load correlated with liver transaminase levels and disease severity. Antiviral treatment led to rapid decline of HSV DNA load and improvement of liver function of patients with HSV hepatitis. The data advocate the prompt and consecutive quantification of the HSV DNA load and liver enzyme levels in plasma of patients suspected of HSV hepatitis as well as those under antiviral treatment.

Prevalence of herpes simplex virus type 1 glycoprotein G (gG) and gI genotypes in patients with herpetic keratitis.

AIM: Recent phylogenetic analyses on the herpes simplex virus type 1 (HSV-1) genes US4, encoding glycoprotein G (gG) and US7, encoding gI, of clinical HSV-1 isolates have led to the classification of HSV-1 into three genotypes, arbitrarily designated as A, B and C. The prevalence of the HSV-1 gG and gI genotypes and their potential disease association was determined in a large cohort of patients with herpetic keratitis (HK). METHODS: Primary corneal HSV-1 isolates of 178 HK patients were genotyped by a PCR-based restriction fragment length polymorphism method targeting the viral genes US4 and US7. RESULTS: Genotype B was more frequently expressed by the corneal HSV-1 isolates compared with genotypes A and C. Fifty-five of 178 corneal isolates (31%) had different genotypes in both loci. No clinically relevant associations were observed between the HSV-1 genotypes and disease outcome in the HK patients studied. CONCLUSIONS: The data presented demonstrate a high frequency of recombinant corneal HSV-1 isolates and suggest that clinical outcome of HSV-1-induced keratitis is independent of a gG or gI genotype.

Imbalances in circulating lymphocyte subsets in Hu antibody associated paraneoplastic neurological syndromes.

In paraneoplastic neurological syndromes (PNS) associated with small cell lung cancer (SCLC) and Hu antibodies, neuron-specific Hu antigens expressed by the tumour hypothetically trigger an immune response that cross-reacts with Hu antigens in the nervous system, resulting in tumour suppression and neuronal damage. To gain more insight into the hypothesized cell-mediated immune pathogenesis of these syndromes, we analysed the circulating lymphocyte subsets in untreated patients with SCLC, PNS and Hu antibodies (n = 18), SCLC without PNS (n = 19) and controls (n = 29) using flow cytometry. SCLC patients with PNS had a variety of imbalances within their circulating lymphocyte subsets as compared with SCLC patients without PNS and healthy controls: (i) a lymphopenia of the major subsets (i.e. B, CD4+ and CD8+ T lymphocytes); (ii) increased proportions of activated CD4+ and CD8+ T cells; (iii) reduced numbers of terminally differentiated effector CD8+ T cells and cells with a cytotoxic T-cell phenotype (CD56+ and CD57+). Although indirect, our data provide further support for the involvement of T cells in the pathogenesis of Hu antibody associated PNS.

Identification of a common HLA-DP4-restricted T-cell epitope in the conserved region of the respiratory syncytial virus G protein.

The cellular immune response to respiratory syncytial virus (RSV) is important in both protection and immunopathogenesis. In contrast to HLA class I, HLA class II-restricted RSV-specific T-cell epitopes have not been identified. Here, we describe the generation and characterization of two human RSV-specific CD4(+)-T-cell clones (TCCs) associated with type 0-like cytokine profiles. TCC 1 was specific for the matrix protein and restricted over HLA-DPB1*1601, while TCC 2 was specific for the attachment protein G and restricted over either HLA-DPB1*0401 or -0402. Interestingly, the latter epitope is conserved in both RSV type A and B viruses. Given the high allele frequencies of HLA-DPB1*0401 and -0402 worldwide, this epitope could be widely recognized and boosted by recurrent RSV infections. Indeed, peptide stimulation of peripheral blood mononuclear cells from healthy adults resulted in the detection of specific responses in 8 of 13 donors. Additional G-specific TCCs were generated from three of these cultures, which recognized the identical (n = 2) or almost identical (n = 1) HLA-DP4-restricted epitope as TCC 2. No significant differences were found between the capacities of cell lines obtained from infants with severe (n = 41) or mild (n = 46) RSV lower respiratory tract infections to function as antigen-presenting cells to the G-specific TCCs, suggesting that the severity of RSV disease is not linked to the allelic frequency of HLA-DP4. In conclusion, we have identified an RSV G-specific human T helper cell epitope restricted by the widely expressed HLA class II alleles DPB1*0401 and -0402. Its putative role in protection and/or immunopathogenesis remains to be determined.

Seal gammaherpesviruses: identification, characterisation and epidemiology.

Phocid herpesvirus type 2 (PhHV-2), tentatively classified as a gammaherpesvirus, has been isolated from European and American harbour seals (Phoca vitulina). Here we describe the isolation and the molecular as well as biological characterisation of different PhHV-2 isolates from harbour seals and grey seals (Halichoerus grypus). Of 522 harbour seals and 231 grey seals that had been admitted to the seal research and rehabilitation centre in Pieterburen, The Netherlands, between 1992 and 2000, 38 and 18%, respectively, proved to have PhHV-2 neutralising antibodies. PhHV-2 was isolated from peripheral blood mononuclear cells (PBMCs) of 12 and 28% of these seropositive animals, respectively, and 26 and 56% of these cell samples, respectively, were positive by PCR analysis. Analysis of amino acid sequences of PCR products and of the growth characteristics of different PhHV-2 isolates indicated that harbour and grey seals are infected with distinct gamma-herpesviruses, which however, may co-circulate between the two species.