Sialoadhesin (CD169) expression in CD14+ cells is upregulated early after HIV-1 infection and increases during disease progression.

BACKGROUND: Sialoadhesin (CD169, siglec-1 or Sn) is an activation marker seen on macrophages in chronic inflammatory diseases and in tumours, and on subsets of tissue macrophages. CD169 is highly expressed by macrophages present in AIDS-related Kaposi's sarcoma lesions. It is also increased on blood monocytes of HIV-1 infected patients with a high viral load despite antiretroviral treatment. METHODOLOGY/PRINCIPAL FINDINGS: We investigated expression of sialoadhesin in untreated HIV-1 and HHV-8 infected patients, by real-time PCR and FACS analysis to establish its expression in relation to infection and disease progression. Patients analysed were either HIV-1 seroconverters (n = 7), in the chronic phase of HIV-1 infection (n = 21), or in the AIDS stage (n = 58). Controls were HHV-8 infected, but otherwise healthy individuals (n = 20), and uninfected men having sex with men (n = 24). Sialoadhesin mRNA was significantly elevated after HIV-1, but not HHV-8 infection, and a further increase was seen in AIDS patients. Samples obtained around HIV-1 seroconversion indicated that sialoadhesin levels go up early in infection. FACS analysis of PBMCs showed that sialoadhesin protein was expressed at high levels by approximately 90% of CD14(+) and CD14(+)CD16(+)cells of HIV-1(+) patients with a concomitant 10-fold increase in sialoadhesin protein/cell compared with uninfected controls. CONCLUSIONS/SIGNIFICANCE: We have shown that sialoadhesin is induced to high levels on CD14(+) cells early after HIV-1 infection in vivo. The phenotype of the cells is maintained during disease progression, suggesting that it could serve as a marker for infection and probably contributes to the severe dysregulation of the immune system seen in AIDS.

Cytomegalovirus and human herpesvirus 8 DNA detection in peripheral blood monocytic cells of AIDS patients: correlations with the presence of Kaposi's sarcoma and CMV disease.

To establish the effect of the presence in blood cells of cytomegalovirus (CMV) and human herpesvirus 8 (HHV8) DNA, two herpesviruses that are activated frequently in AIDS patients, were selected from the Amsterdam Cohort Studies on HIV/AIDS 181 PBMC samples from patients with and without Kaposi's sarcoma (KS), and with and without CMV-related disease. The viral loads of both HHV8 and CMV were determined by real-time PCR at the time of diagnosis of AIDS. There was no significant difference in prevalence and load for CMV between the KS and non-KS patients. The variable related most strongly to KS was the presence of HHV8 DNA in PBMCs, whilst CMV DNA was related to the development of CMV disease and shortened survival. The frequency of detection of HHV8 increased when the patient presented with more severe KS symptoms at diagnosis, but detection of HHV8 DNA did not influence survival. Therefore, HHV8 and CMV DNA measured in the blood of AIDS patients, are each related mainly to the associated disease, and have no additional predictive value in these patients.

SIVdrl detection in captive mandrills: are mandrills infected with a third strain of simian immunodeficiency virus?

A pol-fragment of simian immunodeficiency virus (SIV) that is highly related to SIVdrl-pol from drill monkeys (Mandrillus leucophaeus) was detected in two mandrills (Mandrillus sphinx) from Amsterdam Zoo. These captivity-born mandrills had never been in contact with drill monkeys, and were unlikely to be hybrids. Their mitochondrial haplotype suggested that they descended from founder animals in Cameroon or northern Gabon, close to the habitat of the drill. SIVdrl has once before been found in a wild-caught mandrill from the same region, indicating that mandrills are naturally infected with a SIVdrl-like virus. This suggests that mandrills are the first primate species to be infected with three strains of SIV: SIVmnd1, SIVmnd2, and SIVdrl.

An IL-8 gene promoter polymorphism is associated with the risk of the development of AIDS-related Kaposi's sarcoma: a case-control study.

In a case-control study, we studied the effect of a single nucleotide polymorphism in the IL-8 promoter on the risk of the development of AIDS-related Kaposi's sarcoma (KS). KS developed in 46% of individuals with the TT genotype and in 66% of AA/AT genotypes (P=0.038). Patients with TT genotype were rarely affected with visceral KS (7% versus 36%; P=0.06), which suggests that carriers of the TT genotype are protected from (severe) KS development.

Human herpesvirus 8 load in matched serum and plasma samples of patients with AIDS-associated Kaposi's sarcoma.

Human herpesvirus 8 (HHV-8) (or Kaposi's sarcoma [KS]-associated herpesvirus) is associated with all forms of KS. HHV-8 DNA load in peripheral blood mononuclear cells (PBMCs) of KS patients has been shown to correlate with the clinical stage of the disease. Studies have been done to assess the HHV-8 viral load in different sample types from KS patients and its clinical relevance. This paper describes the design and evaluation of a quantitative real-time (TaqMan) PCR assay for routine diagnosis of HHV-8 infection. The linear dynamic range was 5 to 5 x 10(6) copies of HHV-8 DNA (r(2) > 0.99). The assay is very sensitive, specific, and easily reproducible (less than 2% variability) and can be used for different clinical samples, such as serum, plasma, and PBMCs. The question of which clinical sample, serum or plasma, is preferable for HHV8 DNA testing was addressed, using this newly developed real-time PCR assay. From 85 patients with diagnosed AIDS-KS, matched plasma and serum samples were collected. Of the 85 patients tested, 35 were positive for HHV-8 DNA in both plasma and serum (41%), 8 were positive in serum but not plasma, and 7 had detectable HHV-8 DNA only in plasma. The HHV-8 load was similar in both plasma and serum, and no significant difference was found. However, more inhibition was seen in the plasma samples with the use of a system quality control, seal herpesvirus type 1. Therefore, our results suggest that serum is the preferred material for HHV-8 load testing, since there is less possible hindrance in the amplification than with plasma.

Identification of sequential viral escape mutants associated with altered T-cell responses in a human immunodeficiency virus type 1-infected individual.

Control of viremia in natural human immunodeficiency virus type 1 (HIV-1) infection in humans is associated with a virus-specific T-cell response. However, still much is unknown with regard to the extent of CD8(+) cytotoxic T-lymphocyte (CTL) responses required to successfully control HIV-1 infection and to what extent CTL epitope escape can account for rises in viral load and ultimate progression to disease. In this study, we chose to monitor through full-length genome sequence of replication-competent biological clones the modifications that occurred within predicted CTL epitopes and to identify whether the alterations resulted in epitope escape from CTL recognition. From an extensive analysis of 59 biological HIV-1 clones generated over a period of 4 years from a single individual in whom the viral load was observed to rise, we identified the locations in the genome of five CD8(+) CTL epitopes. Fixed mutations were identified within the p17, gp120, gp41, Nef, and reverse transcriptase genes. Using a gamma interferon ELIspot assay, we identified for four of the five epitopes with fixed mutations a complete loss of T-cell reactivity against the wild-type epitope and a partial loss of reactivity against the mutant epitope. These results demonstrate the sequential accumulation of CTL escape in a patient during disease progression, indicating that multiple combinations of T-cell epitopes are required to control viremia.

Gene expression profile of AIDS-related Kaposi's sarcoma.

BACKGROUND: Kaposi's Sarcoma (KS) is a proliferation of aberrant vascular structures lined by spindle cells, and is caused by a gammaherpes virus (HHV8/KSHV). Its course is aggravated by co-infection with HIV-1, where the timing of infection with HIV-1 and HHV8 is important for the clinical outcome. METHODS: In order to better understand the pathogenesis of KS, we have analysed tissue from two AIDS-KS lesions, and from normal skin by serial analysis of gene expression (SAGE). Semi-quantitative RT-PCR was then used to validate the results. RESULTS: The expression profile of AIDS-related KS (AIDS-KS) reflects an active process in the skin. Transcripts of HHV8 were found to be very low, and HIV-1 mRNA was not detected by SAGE, although it could be found using RT-PCR. Comparing the expression profile of AIDS-KS tissue with publicly available SAGE libraries suggested that AIDS-KS mRNA levels are most similar to those in an artificially mixed library of endothelial cells and leukocytes, in line with the description of KS lesions as containing spindle cells with endothelial characteristics, and an inflammatory infiltrate. At least 64 transcripts were found to be significantly elevated, and 28 were statistically downregulated in AIDS-KS compared to normal skin. Five of the upregulated mRNAs, including Tie 1 and sialoadhesin/CD169, were confirmed by semi-quantitative PCR to be elevated in additional AIDS-KS biopsies. Antibodies to sialoadhesin/CD169, a known marker of activated macrophages, were shown to specifically label tumour macrophages. CONCLUSION: The expression profile of AIDS-KS showed 64 genes to be significantly upregulated, and 28 genes downregulated, compared with normal skin. One of the genes with increased expression was sialoadhesin (CD169). Antibodies to sialoadhesin/CD169 specifically labelled tumour-associated macrophages, suggesting that macrophages present in AIDS-KS lesions belong to a subset of human CD169+ macrophages.

Primary effect of chemotherapy on the transcription profile of AIDS-related Kaposi's sarcoma.

BACKGROUND: Drugs & used in anticancer chemotherapy have severe effects upon the cellular transcription and replication machinery. From in vitro studies it has become clear that these drugs can affect specific genes, as well as have an effect upon the total transcriptome. METHODS: Total mRNA from two skin lesions from a single AIDS-KS patient was analyzed with the SAGE (Serial Analysis of Gene Expression) technique to assess changes in the transcriptome induced by chemotherapy. SAGE libraries were constructed from material obtained 24 (KS-24) and 48 (KS-48) hrs after combination therapy with bleomycin, doxorubicin and vincristine. KS-24 and KS-48 were compared to SAGE libraries of untreated AIDS-KS, and to libraries generated from normal skin and from isolated CD4+ T-cells, using the programs USAGE and HTM. SAGE libraries were also compared with the SAGEmap database. RESULTS: In order to assess the primary response of AIDS-related Kaposi's sarcoma (AIDS-KS) to chemotherapy in vivo, we analyzed the transcriptome of AIDS-KS skin lesions from a HIV-1 seropositive patient at two time points after therapy. The mRNA profile was found to have changed dramatically within 24 hours after drug treatment. There was an almost complete absence of transcripts highly expressed in AIDS-KS, probably due to a transcription block. Analysis of KS-24 suggested that mRNA pool used in its construction originated from poly(A) binding protein (PABP) mRNP complexes, which are probably located in nuclear structures known as interchromatin granule clusters (IGCs). IGCs are known to fuse after transcription inhibition, probably affecting poly(A)+RNA distribution.Forty-eight hours after chemotherapy, mRNA isolated from the lesion was largely derived from infiltrating lymphocytes, confirming the transcriptional block in the AIDS-KS tissue. CONCLUSIONS: These in vivo findings indicate that the effect of anti-cancer drugs is likely to be more global than up- or downregulation of specific genes, at least in this single patient with AIDS-KS. The SAGE results obtained 24 hrs after chemotherapy can be most plausibly explained by the isolation of a fraction of more stable poly(A)+RNA.