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PubMed2006

Comparison of a LightCycler-based real-time PCR for quantitation of Epstein-Barr viral load in different clinical specimens with semiquantitative PCR.

Measurement of viral load is important in predicting and monitoring of Epstein-Barr virus (EBV)-associated diseases especially in immunocompromised patients. The objectives of this study were the development of a LightCycler-based real-time PCR assay using primers and probes which recognize the virus capsid antigen p23-encoding region and its comparison to the semiquantitative PCR. The LightCycler protocol shows a high degree of specificity and inter- and intra-assay reproducibility. Concerning sensitivity, a good correlation between both methods was demonstrated for standard plasmid DNA, reference DNA isolated from the EBV-genome containing Namalwa cell line, and DNA extracted from plasma/cerebrospinal fluid (CSF). The detection limit was determined with 1 copy/microl eluate for the standard plasmid DNA and with 500 copies/ml plasma or CSF. For DNA derived from peripheral blood mononuclear cells (PBMCs), a decrease of sensitivity by factor 10-100 was found when larger amounts of background DNA (500 and 100 ng) were used presuming an inhibitory effect of cellular DNA. This was supported by running dilutions of the plasmid standard carried out with EBV-negative Ramos cell DNA. Thus, the cut-off level was estimated with 100-500 copies/10(5) PBMCs, when 50 or 10 ng total DNA were tested. The results indicate that the real-time PCR described here is a first line tool for the determination of viral load in plasma and CSF. Semiquantitative nested PCR is used for screening of PBMCs viral load. Positive specimens containing more than 500 copies/10(5) cells are measured for exact values by real-time PCR. To circumvent inhibitory effects of cellular DNA, measurements should be carried out generally with 50-10 ng DNA.

Capsid Proteins↗

PubMed2002

[Clinical study on treatment of HIV infected persons based on viral load detection and CD4+ T lymphocyte counting].

OBJECTIVE: To study the usage of viral load and CD4+ cell count methods in evaluating the effects of clinical treatment in HIV infected people. METHODS: Totally 73 cases of HIV infected persons were studied with clinical observation and laboratory examinations, six cases were treated with cocktail therapy, 36 cases with chinese herbs and the other 31 cases were untreated. RESULTS: The results indicated that the viral load levels in cocktail therapy group were significantly lower than the other two groups within 3 months and then kept at very low level. The CD4+ T lymphocyte levels showed a significant increase after 3 months and kept rising up. The chinese herb group, however, had no significant difference in viral load level and CD4+ T lymphocyte level as compared with untreated group. But in clinical observation chinese herbs showed the effect of improving clinical status in some cases. CONCLUSIONS: The authors conclude that the viral load and CD4+ count are efficient methods in clinical evaluation of HIV treatment, especially in routine anti-HIV therapy. As for the chinese herbs treatment, these two monitors did not reflect changes in clinical status.

Anti-HIV Agents↗

PubMed2000

Response of foot-and-mouth disease virus to increased mutagenesis: influence of viral load and fitness in loss of infectivity.

Passage of foot-and-mouth disease virus (FMDV) in cell culture in the presence of the mutagenic base analog 5-fluorouracil or 5-azacytidine resulted in decreases of infectivity and occasional extinction of the virus. Low viral loads and low viral fitness enhanced the frequency of extinction events; this finding was shown with a number of closely related FMDV clones and populations differing by up to 10(6)-fold in relative fitness in infections involving either single or multiple passages in the absence or presence of the chemical mutagens. The mutagenic treatments resulted in increases of 2- to 6.4-fold in mutation frequency and up to 3-fold in mutant spectrum complexity. The largest increase observed corresponded to the 3D (polymerase)-coding region, which is highly conserved in nonmutagenized FMDV populations. As a result, nucleotide sequence heterogeneity for the 3D-coding region became very similar to that for the variable VP1-coding region in FMDVs multiply passaged in the presence of chemical mutagens. The results suggest that strategies to combine reductions of viral load and viral fitness could be effectively associated with extinction mutagenesis as a potential new antiviral strategy.

Amino Acid Substitution↗

PubMed2002

HIV-1 infection and low steady state viral loads.

Highly active antiretroviral therapy (HAART) reduces the viral burden in human immunodeficiency virus type 1 (HIV-1) infected patients below the threshold of detectability. However, substantial evidence indicates that viral replication persists in these individuals. In this paper we examine the ability of several biologically motivated models of HIV-1 dynamics to explain sustained low viral loads. At or near drug efficacies that result in steady state viral loads below detectability, most models are extremely sensitive to small changes in drug efficacy. We argue that if these models reflect reality many patients should have cleared the virus, contrary to observation. We find that a model in which the infected cell death rate is dependent on the infected cell density does not suffer this shortcoming. The shortcoming is also overcome in two more conventional models that include small populations of cells in which the drug is less effective than in the main population, suggesting that difficulties with drug penetrance and maintenance of effective intracellular drug concentrations in all cells susceptible to HIV infection may underlie ongoing viral replication.

Antiretroviral Therapy, Highly Active↗

PubMed2004

Serial changes of intrathecal viral loads evaluated by chemiluminescence assay and nested PCR with aciclovir treatment in herpes simplex virus encephalitis.

OBJECTIVE: We assessed the potential for estimating the effects of antiviral therapy on the clearance of intrathecal herpes simplex virus (HSV) antigens as evaluated by the chemiluminescence assay (CL) and on that of intrathecal HSV-DNA as evaluated by the nested polymerase chain reaction (PCR) in serial patients with herpes simplex virus encephalitis (HSVE). METHODS: The materials comprised serial cerebrospinal fluid (CSF) samples from 18 patients with HSVE. All patients were diagnosed as having HSVE retrospectively based on the detection of intrathecal HSV antigens by the CL, that of HSV-DNA by the nested PCR, and also serological confirmation of intrathecal antibody production. The relationships between the days of aciclovir therapy and serial HSV viral loads as evaluated by the CL and nested PCR in the serial CSFs were assessed. RESULTS: The serial intrathecal viral loads evaluated by the CL and nested PCR declined after the commencement of aciclovir administration in all patients. The serial alterations of the intrathecal viral load evaluated by the CL in each patient were similar to those of the intrathecal viral load evaluated by the nested PCR. The initial and maximum viral loads evaluated by the CL and nested PCR showed a wide distribution in the CSF samples taken from the patients with poor and good outcomes. Differences in the means of the viral loads in the CSF samples taken from the patients between a poor outcome and a good outcome were not evident. A transient increase of viral load as evaluated by these two methods was noted in the same 4 patients. The viral loads in these 4 patients also declined in the subsequent CSF samples. The outcome of these 4 patients was good in one patient and poor in the others. CONCLUSION: Evaluation of intrathecal viral antigens by the CL has a potential for estimating the effects of antiviral therapy, as does evaluation of the intrathecal HSV-DNA by the nested PCR. The intrathecal viral loads evaluated by CL and nested PCR were not a predictor of outcome in HSVE.

Acyclovir↗

PubMed1998

Immunization with both T cell-dependent and T cell-independent vaccines augments HIV viral load secondarily to stimulation of tumor necrosis factor alpha.

Vaccination of HIV-infected individuals increases HIV viral load, reduces CD4 cell counts, and might influence disease progression. Because these deleterious effects are postulated to be secondary to a direct activation of T lymphocytes induced by the immunogen, we compared immunologic and virologic effects of a T cell-dependent and a T cell-independent vaccine. Seventeen HIV-infected children were immunized with influenza (FLU) (T cell-dependent) or pneumococcal (PNEUMO) (T cell-independent) vaccines. HIV viral load and type 1 (IL-2 and IFN-gamma) and type 2 (IL-4 and IL-10) cytokine production were evaluated before and 7, 14, and 28 days after vaccination. Slopes of CD4 cell counts analyzed 6 months before and 6 months after vaccination were not significantly different. HIV viral load increased in both groups of children despite the fact that type 1 cytokine production and the type 1-to-type 2 ratio increased in FLU-vaccinated but not in PNEUMO-vaccinated patients. Thus, an increase in HIV viral load in the absence of T cell activation (as measured by cytokine production) was observed in PNEUMO-vaccinated children. Because polysaccharides of the bacterial cell wall stimulate TNF-alpha production by monocyte-macrophages and TNF-alpha was shown to stimulate HIV replication directly on activation of NF-kappa b after binding the long terminal repeat (LTR) sequences of HIV, we measured TNF-alpha production and observed a significant increase in both groups of vaccines. These data suggest that an increase in HIV viral load can be observed in vaccinated HIV-infected children even independent of direct antigen-induced activation of T lymphocytes, and that augmented production of TNF-alpha might play a role in this phenomenon.

Bacterial Vaccines↗

PubMed2007

Analytical and clinical sensitivity of the Procleix Ultrio HIV-1/HCV/HBV assay in samples with a low viral load.

BACKGROUND AND OBJECTIVES: The Procleix Ultrio human immunodeficiency virus type 1 (HIV-1)/hepatitis C virus (HCV)/hepatitis B virus (HBV) (Ultrio) assay simultaneously detects HIV-1 RNA, HCV RNA and HBV DNA in individual blood donations. The main objective of the study was to assess the analytical and clinical sensitivity of the multiplex and discriminatory probe assays in samples with a low viral load. MATERIAL AND METHODS: The VQC HIV RNA genotype B, HCV RNA genotype 1 and HBV DNA genotype A standard dilutions were tested in 26 repeats. The probability of detection by Ultrio was compared with previously obtained data of the Procleix Duplex HIV-1/HCV assay on the same reference panels. A selection of 121 anti-HIV-1, 138 anti-HCV and 190 HBsAg positive samples from patients receiving antiviral therapy were tested. The majority of patient samples had a viral load below the detection limit of the diagnostic nucleic acid test assays, which made them suitable to evaluate the performance of the multiplex and discriminatory assays on yield cases with a similar low viral load. RESULTS: The 95% and 50% detection end-points of the Ultrio assay along with the corresponding 95% confidence intervals are 53.7 (32.9-117.2) and 8.6 (6.2-12.1) geq/ml for HIV-1 RNA, 30.3 (19.0-62.4) and 5.2 (3.7-7.2) geq/ml for HCV RNA and 393.7 (147.9-6978) and 54.5 (22.4-143.8) geq/ml for HBV DNA. The analytical sensitivity of Ultrio expressed as a potency factor relative to previously obtained Duplex results on the same HIV-1 RNA and HCV-RNA standard dilutions was 1.09 (0.20-6.10) and 1.11 (0.21-5.89), respectively. The assay detected all 22 HIV-1 infected patients with viral load > 50 copies/ml, and 41 of 99 patients (41%) with viral load < 50 copies/ml, of which 23 (56%) were detected by the discriminatory assay. All 47 patients with HCV RNA load > 521 IU/ml and 10/91 polymerase chain reaction-negative patients with viral load < 50 IU/ml tested positive in Ultrio assay of which five were missed in the discriminatory test. The assay detected 53/55 HBV infected patients (96%) with viral load > 250 copies/ml and 108/135 patients (80%) with viral load < 250 copies/ml of which 17 (16%) were missed by the discriminatory test. CONCLUSIONS: The new Procleix Ultrio assay is as sensitive as the Procleix Duplex assay for HIV-1 and HCV detection meeting the requirements of universal guidelines. The ability of the assay to detect HBV DNA in low viral load samples could be useful for screening blood. Inevitable negative results of discriminatory probe assays caused by stochastic sample variation will reduce the chance of recognizing low viraemic blood donors detected by individual donation nucleic acid test.

Blood Donors↗

PubMed2001

[Correlation between CD4 lymphocytes and viral load in patients with HIV and tuberculosis].

OBJECTIVE: A retrospective study of the correlation between CD4 lymphocytes and the viral load in 16 HIV-patients with tuberculosis. MATERIAL AND METHODS: The clinical forms of presentation of tuberculosis were classified according to the location/s of the disease into: pulmonary, distinguishing between typical pulmonary and atypical according to the radiological pattern; extrapulmonary; mixed forms: pulmonary and extrapulmonary; and miliary tuberculosis. RESULTS: Tuberculosis was exclusively pulmonary in 7 cases (44%), all were atypical; extrapulmonary 6 (38%); mixed 2 (12%); and miliary 1 (6%). The mean CD4 lymphocyte count was 111.1 (range 5-360), in 11 (69%) the counts were below 200 cells/mm3. The lowest CD4 count was in the mixed forms with a mean of 45 cells/mm3 whilst the highest was obtained in pulmonary forms with a mean of 128.3 cells/mm3. The mean viral load was 4.82 log (range, 0-5.93), the highest load was for mixed forms with a mean 5.69 log, whereas the lowest load was for pulmonary forms with a mean of 4.19 log. No significant correlation was observed between CD4 lymphocytes and viral load (correlation coefficient--0.1163). CONCLUSIONS: Though no significant correlation was observed, a high CD4 was associated to a low viral load and inversely a low CD4 with a high viral load.

AIDS-Related Opportunistic Infections↗

PubMed2000

Effect of PMPA and PMEA on the kinetics of viral load in simian immunodeficiency virus-infected macaques.

In this study we compared the effect of postexposure treatment of the acyclic nucleoside analogs 9-(2-phosphonylmethoxyethyl)-adenine (PMEA) and 9-(2-phosphonylmethoxypropyl)-adenine (PMPA) on the kinetics of viral load in the blood and lymph nodes of rhesus macaques chronically infected with SIVmac251 for 18 weeks. Two of the four macaques treated with PMPA (20 mg/kg per day) for 28 consecutive days had demonstrable reductions in viral loads of 1.5 and 3 logs. Three of four macaques given the same dosing regimen of PMEA had viral load reductions ranging from 1.25 to 2.8 logs. Furthermore, treatment with either drug caused a reduction in virus burden in the lymph nodes by 2 weeks posttreatment. However, in both PMEA- and PMPA-treated animals, viral loads rebounded to day of treatment levels by 2 weeks after termination of treatment. The extent to which viral load was suppressed was similar for both drugs. In contrast, viral loads in three of four mock-treated animals remained persistently high throughout the study. This study has demonstrated that postexposure treatment with these acyclic nucleoside analogs could modulate the kinetics of viral load reduction in some animals.

Adenine↗

PubMed1993

Cellular and plasma viral load in patients infected with HIV-2.

OBJECTIVE: To determine circulating viral load in HIV-2-infected individuals. METHODS: Viral load was determined in 40 HIV-2-infected adults using standardized quantitative cell and qualitative plasma viraemia assays. We also tested for proviral HIV-2 DNA using single and nested polymerase chain reaction (PCR) in fresh lymphocytes from 27 subjects. The results were compared, on the basis of the CD4+ lymphocyte count, with our published data for HIV-1 infection. RESULTS: HIV-2 was isolated from peripheral blood mononuclear cells (PBMC) from 19 individuals and plasma from four patients. The rate of cell and plasma viraemia positivity correlated with the CD4+ cell count and HIV-2 virus load increased as the CD4+ cell count fell. The cellular HIV-2 load in the patients with a CD4+ count < 200 x 10(6)/l was similar to reported values for HIV-1, but the HIV-2 isolation rate from the plasma of these individuals was significantly lower than for HIV-1. When the CD4+ count was between 200 and 500 x 10(6)/l, the rate of HIV-2 isolation from plasma and the cellular virus load were both significantly lower than for HIV-1. When the CD4+ count was > 500 x 10(6)/l, HIV-1 and HIV-2 were undetectable in plasma and HIV-1 was isolated from PBMC in significantly more cases than HIV-2. By single PCR, amplification were positive in 14 out of 27 subjects and there was a correlation between positivity and CD4+ cell count. By nested PCR, only four of the 27 subjects, all with a high CD4+ count, remained negative. CONCLUSIONS: Differences in viral load between individuals infected with HIV-2 and those infected with HIV-1 could partly account for reported differences in the pathogenicity of the two viruses.

Adult↗

PubMed2005

Epstein-Barr viral load as a marker of lymphoma in AIDS patients.

Epstein-Barr virus (EBV) is implicated in the pathogenesis of acquired immunodeficiency syndrome (AIDS) lymphoma, and viral DNA is present within the malignant cells in about half of affected patients. We examined the extent to which EBV viral load is elevated in the plasma of AIDS lymphoma patients compared to AIDS patients with opportunistic infections. Sixty-one AIDS patients were studied including 35 with lymphoma (24 non-Hodgkin, six Hodgkin, and five brain lymphoma) and 26 with various opportunistic infections. In situ hybridization revealed EBV encoded RNA (EBER) expression in the malignant cells of 17/28 AIDS lymphomas (61%). In 232 serial plasma samples from 35 lymphoma patients and in 128 samples from AIDS controls, EBV viral load was assayed by quantitative-polymerase chain reaction (Q-PCR) using a TaqMan probe targeting the BamH1W sequence. EBV was detected in plasma from all 17 EBER-positive AIDS lymphoma patients, with viral loads ranging from 34 to 1,500,000 copies per ml (median 3,210). Viral load usually fell rapidly upon initiation of lymphoma therapy and remained undetectable except in two patients with persistent tumor. In 11 AIDS patients, whose lymphoma lacked EBER expression, and in 26 control patients without lymphoma, levels of EBV in plasma were usually low or undetectable (range 0-1,995 and 0-2,409, median 0 and 0, respectively). There was no association between EBV viral load and human immunodeficiency virus (HIV) load or CD4 count. In conclusion, EBV viral load shows promise as a tool to assist in diagnosis and management of EBV-related lymphoma patients.

Acquired Immunodeficiency Syndrome↗

PubMed2004

Older age and plasma viral load in HIV-1 infection.

BACKGROUND: The purpose of the study was to examine the relationship between age and plasma viral load in HIV-1-infected individuals. DESIGN: The experimental method was to recruit older (> 50 years of age) and younger (18-39 years of age) HIV-1-infected individuals. The plasma viral load was measured using the Roche Molecular Systems UltraSensitive Roche HIV-1 Monitor test reflexively with the standard Amplicor HIV Monitor test to quantify viral load in the range of 50-750,000 copies of HIV-1 RNA/ml plasma. SUBJECTS: A total of 135 HIV-1-seropositive individuals (at Centers for Disease Control and Prevention early symptomatic stage B or late symptomatic stage/AIDS C) were enrolled as part of a larger cohort also consisting of HIV-1-seronegative individuals. RESULTS: A generalized linear models statistical analysis was conducted in order to evaluate age category as a predictor of plasma viral load. The result was a significant effect of age category, with older age associated with a lower plasma viral load. The association held controlling for antiretroviral therapy usage, disease stage, antiretroviral medication adherence, HIV-1 serostatus duration, alcohol and substance use, recent sexually transmitted disease, and sociodemographics (except income). CONCLUSION: Older age was associated with lower levels of HIV-1 replication in this sample, independent of antiretroviral therapy usage, regimen adherence, and disease stage. It is suggested that the effect may be caused by changes in viral evolution or immunological monitoring specific to older individuals with HIV-1 infection.

Adult↗

PubMed2001

The significance of human papillomavirus viral load in prediction of histologic severity and size of squamous intraepithelial lesions of uterine cervix.

OBJECTIVES: Persistence of high-risk types of human papillomavirus (HPV) in cervical scrapes is responsible for the development, maintenance, and progression of squamous intraepithelial lesions (SILs). Previous studies of viral load and histologic severity have ended with controversial results. This study evaluated the relationships of HPV viral load with size and histologic severity of cervical lesions, which has not been reported previously. METHODS: By using Hybrid Capture II, DNA level of high-risk HPVs was determined in cervical scrapes and correlated with lesion size and histologic confirmation for 73 women referred for colposcopy. The lesion size was classified as nonvisible (n = 12), small (< or =2/5 of the 12x colposcopic visual filed, n = 36), and large (>2/5 of the 12x field, n = 25) lesions. The final disease status was categorized as high-grade SIL (HSIL)/squamous cell carcinoma (SCC) (designated HSIL+) (n = 32), low-grade SIL (LSIL) (n = 19), and no detectable SIL (n = 22). RESULTS: A distinct upward trend of high-risk HPV DNA levels paralleled increasing size and histologic severity of cervical lesions (P = 0.003 and 0.001, respectively). With respect to relative risk, women who had high viral load of HPV were at significantly greater risk for large lesion size (odds ratio [OR] = 5.3, 95% confidence interval [CI] = 1.1-24.9) and HSIL+ (OR = 35.0, 95% CI = 4.2-294.5). Of particular note, the risk of developing large lesion size and HSIL+ significantly increased with increasing viral load of HPV (P values for trend test were 0.008 and 0.0004, respectively). In contrast, there were no significant associations of trend in viral load with risk in small lesion size and LSIL. CONCLUSIONS: The present study revealed that the effect of HPV infection on SIL development is highly influenced by high viral load and highlighted a potential application of viral load testing in predicting the size and severity of lesions of the uterine cervix.

Adult↗

PubMed2006

Mutations in carboxy-terminal part of E2 including PKR/eIF2alpha phosphorylation homology domain and interferon sensitivity determining region of nonstructural 5A of hepatitis C virus 1b: their correlation with response to interferon monotherapy and viral load.

AIM: To study the amino acid substitutions in the carboxy (C)-terminal part of E2 protein and in the interferon (IFN) sensitivity determining region (ISDR) and their correlation with response to IFN and viral load in 85 hepatitis C virus (HCV)-1b-infected patients treated with IFN. METHODS: The C-terminal part of E2 (codons 617-711) including PKR/eIF2alpha phosphorylation homology domain (PePHD) and ISDR was sequenced in 85 HCV-1b-infected patients treated by IFN monotherapy. RESULTS: The amino acid substitutions in PePHD detected only in 4 of 85 patients were not correlated either with response to IFN or with viral load. The presence of substitutions in a N-terminal variable region (codons 617-641) in the C-terminal part of E2 was significantly correlated with both small viral load (33.9% vs 13.8%, P = 0.0394) and sustained response to IFN (25.0% vs 6.9%, P = 0.0429). Four or more substitutions in ISDR were significantly correlated with both small viral load (78.6% vs 16.2%, P < 0.0001) and sustained response to IFN (85.7% vs 2.9%, P < 0.0001). In multivariate analysis, ISDR in nonstructural (NS) 5A (OR = 0.39, P < 0.0001) and N-terminal variable region (OR = 0.51, P = 0.039) was selected as the independent predictors for small viral load, and ISDR (OR = 39.0, P < 0.0001) was selected as the only independent predictor for sustained response. CONCLUSION: The N-terminal variable region in the C-terminal part of E2 correlates with both response to IFN monotherapy and viral load and is one of the factors independently associated with a small viral load.

Adult↗

PubMed2000

Relationship between viral load in blood, cerebrospinal fluid, brain tissue and isolated microglia with neurological disease in macaques infected with different strains of SIV.

The role of the viral burden in the brain for the pathogenesis of human immunodeficiency virus-associated neurological disorders is still unclear. To address this issue, we have quantified the viral load in plasma, cerebrospinal fluid (CSF) and brain tissue of macaques infected with simian immunodeficiency virus (SIV). We discovered that the viral strain used for infection determines the replicative capacity in microglial cells as well as the extent of neuropathological lesions and the occurrence of neurological symptoms. Moreover, the viral load in the brain parenchyma correlated with the development of overt neurological disease whereas the one in plasma did not. By comparing the viral load in three different compartments, we demonstrated that the viral burden in the CSF is influenced both by the viral replication in the periphery as well as in the brain parenchyma. According to these results, it is not the absolute amount of viral load in the CSF but rather the viral antigen contributed by the viral production within the brain which correlates with the development of neurological disease. In longitudinal studies, we observed that this autochthonous virus production, as evidenced by a ratio of the viral load in CSF to the one in plasma, takes place for a prolonged period of time before overt neurological signs are manifested. This finding suggests that this ratio could be used as a prognostic marker for immunodeficiency virus-induced neurological disease.

AIDS-Related Complex↗

PubMed2002

Monitoring of viral load by quantitative plasma PCR during active cytomegalovirus infection of individual liver transplant patients.

A quantitative PCR test, the Cobas Amplicor CMV Monitor, was used for the monitoring of viral load in the peripheral blood of 27 individual liver transplant patients and correlated with cytomegalovirus (CMV) pp65 antigenemia. Altogether, 243 specimens were analyzed. During the first 3 months, 20 patients showed PCR positivity which correlated with pp65 antigenemia. Of those, 13 patients developed symptomatic CMV infection 27 to 52 days after transplantation, with a significantly higher peak viral load in PCR and in pp65 assay compared with the seven asymptomatic infections (median 10,200 versus 2,240 copies/ml, P < 0.05, and median 100 versus 30 pp65-positive cells/50,000 leukocytes, P < 0.01). Five were primary infections of D+/R- cases (donor CMV seropositive and recipient seronegative) and demonstrated, except in one case, a high peak viral load (>10,000 copies/ml; range, 10,200 to 21,600 copies, and > or =50 positive cells, range, 50 to 800 cells). The peak viral loads of the six D+/R+ patients with symptomatic infection varied widely (range, 2,290 to 126,000 copies and 50 to 300 positive cells). Two D-/R+ patients developed symptomatic infection with a lower viral load (range, 1,120 to 6,510 copies and 25 to 100 positive cells). All symptomatic infections were successfully treated with ganciclovir. The asymptomatic infections all in D+/R+ patients with low copy numbers (<5,500 copies) were monitored until CMV disappeared. One of the seven PCR-negative patients had one sample with low antigenemia, but the subsequent specimens were all negative. The time-related correlation of the two methods was also good. In summary, quantitative PCR could equally well be used as the CMV pp65 assay for the monitoring of viral load in individual transplant patients.

Adult↗

PubMed2005

Viral load change and sequential evolution of entire hepatitis C virus genome in Irish recipients of single source-contaminated anti-D immunoglobulin*.

In hepatitis C virus (HCV) infection, serum viral load is important in the prediction of therapeutic efficacy. However, factors that affect the viral load remain poorly understood. To identify viral genomic elements responsible for the viral load, we investigated samples from a population of Irish women who were iatrogenically infected from a single HCV source by administration of HCV 1b-contaminated anti-D immune globulin between 1977 and 1978 (Kenny-Walsh, N Engl J Med 1999; 340: 1228). About 15 patients were divided into two groups, viral load increasing group (11 patients) and decreasing group (4 patients). Pairs of sera were collected from each patient at interval between 1.1 and 5.8 years. Full-length sequences of HCV genome were determined, and analyzed for changes in each patient. Sliding window analysis showed that the decreasing group had significantly higher mutation rates in a short segment of NS5B region that may affect the activity of RNA-dependent RNA polymerase. By comparing each coding regions, significantly higher mutation numbers were accumulated in NS5A region in the increasing group than the decreasing group (0.92 vs 0.16 nucleotides/site/year, P = 0.021). The mutation in certain positions of the HCV genome may be determinant factors of the viral load in a relatively homogeneous patient population.

Amino Acid Sequence↗

PubMed2005

[Influence of the clinical and biological variables CD4 and viral load on the neuropsychologic efficiency of patients with HIV-1 infection].

INTRODUCTION: Diverse investigations have tried to relate the neuropsychologic efficiency with the levels of CD4 and viral load, however the results don't seem to be conclusive. The objective of the present investigation is to determine the relationship grade among the variable level of CD4 and viral load and the neuropsychologic efficiency of patients HIV-I infected. METHOD: A total of 88 seropositive patients of the Complexo Hospitalario Cristal-Piñor (Ourense), in different phases of the infection (A=30,B=17 and C=41) they were recruited after completing a series of inclusion approaches to participate in the study. A total of 4 four patients was rejected by not completing the proposed approaches. To all they were applied a neuropsychologic battery, an evaluation of the anxious-depressive symptomatology and an interview over sociodemographical, toxicological, neuropsychiatrics and clinical-biological aspects. In the same day of the evaluation the levels of CD4 and viral load were determined in peripheral blood. Previous to establish the correlation levels among the studied variables--levels of CD4, viral load in peripheral blood and neuropsychologic efficiency--it was necessary to carry out a factorial analysis to determine the factors that it evaluated the neuropsychologic battery and to standardize the punctuations, transforming them in typical punctuations. Then, the execution levels and neurocognitive deterioration was determined, contrasting them with a group designed control adhoc. Later on, it practiced correlation analysis and multiple regression. RESULTS AND DISCUSSION: The result of the correlates analyses and of regression it seems to indicate the relationship absence between CD4 and viral load in peripheral blood with each one of the five factors studied neuropsychologic (visual memory, attention/psychomotor speed, ver bal intelligence/abstract thought, verbal memory for digits and words and verbal memory for texts). Our data are coincident with other many investigations that throw similar data. The study of this thematic one requires more investigation with innovative methodological focuses. CONCLUSIONS: The neuropsychological execution, seems to be independent of the levels of CD4 and viral load. The disagreement among the investigators, perhaps, respond to complex methodological questions.

CD4 Lymphocyte Count↗