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At least 163 records · Page 9Linked to original sources
PubMed1995

Standardization of absolute CD4+ lymphocyte counts across laboratories: an evaluation of the Ortho CytoronAbsolute flow cytometry system on normal donors.

The Ortho CytoronAbsolute is a flow cytometer designed to provide direct absolute counts of lymphocytes and their subsets from a single instrument. This study was designed to determine the performance of four geographically separated CytoronAbsolute instruments using 24-h-old, shipped, whole blood samples and to compare the results obtained on the CytoronAbsolute to those obtained using combinations of hematology instruments and other flow cytometers. The absolute count feature of the CytoronAbsolutes located at the four sites were cross calibrated and gave across-site coefficients of variation (CVs) of <4.0% for absolute count and 8.2% for absolute lymphocyte count. The calibration was stable for at least 2 months. Absolute lymphocyte counts and lymphocyte percentage immunophenotypes were determined on blood from 50 healthy human immunodeficiency virus (HIV)-seronegative donors. There were no significant site-to-site differences (each P > .05) in CD3+/CD4+ absolute lymphocyte counts determined on the CytoronAbsolute. In contrast, there was a significant site-to-site difference (P < .001) between sites 2 and 3 and sites 3 and 4 in the absolute CD3+/CD4+ lymphocyte counts determined via the conventional method of combining a flow cytometry-derived percentage with a hematology instrument-derived lymphocyte count. There was no significant difference (P = .388) in CD3+/CD4+ lymphocyte percent determinations between the CytoronAbsolute and the FACScan or Profile II flow cytometers used in this study. These results demonstrate that different operators can cross calibrate CytoronAbsolutes for absolute CD3+/CD4+ lymphocyte subset determinations, even over large geographic distances.

CD4 Lymphocyte Count↗
PubMed1990

CD4 lymphocyte counts and serum p24 antigen of no diagnostic value in monitoring HIV-infected patients with pulmonary symptoms.

The diagnostic value of the CD4 cell counts and the HIV p24 antigen were evaluated in a consecutive series of 105 HIV-infected patients experiencing 128 episodes of pulmonary symptoms which required bronchoscopy. One-third of patients with opportunistic infection (OI) had CD4 counts greater than 0.200 x 10(9)/l, and 60% of patients without OI had CD4 counts less than 0.200 x 10(9)/l; 47 and 42% of patients with and without OI, respectively, had detectable p24 antigen in serum. Only 36% of the patients with OI presented the combination of CD4 cells less than 0.200 x 10(9)/l and p24 in serum. In conclusion, the CD4 cell counts and the presence of p24 antigen in serum had a very limited predictive value for the presence of OI in HIV-infected patients with pulmonary symptoms.

Acquired Immunodeficiency Syndrome↗
PubMed1993

Crossover of human immunodeficiency virus-infected patients from aerosolized pentamidine to trimethoprim-sulfamethoxazole: lack of hematologic toxicity and relationship of side effects to CD4+ lymphocyte count.

Trimethoprim-sulfamethoxazole (TMP/SMZ) was given in a crossover study to 130 human immunodeficiency virus-infected patients who had been receiving aerosolized pentamidine; 86 (66%) successfully crossed over to TMP/SMZ without hypersensitivity reactions or hematologic toxicity. No significant changes occurred in mean hemoglobin concentration, leukocyte count, or platelet count between study enrollment and 12-month follow-up. Predominant side-effects, in 41 patients (33.8%), were fever and maculopapular rashes, which resolved promptly with discontinuation of TMP/SMZ. The mean time to first side effect was 12.3 days, and 86% of side effects developed within 30 days. Three patients experienced toxicity serious enough to warrant hospitalization. Of patients with < or = 200 CD4+ lymphocytes/mm3, 57% developed rashes after the cross-over compared with only 27% of patients with higher CD4+ cell counts. Many patients currently receiving aerosolized pentamidine can be safely crossed over without hematologic toxicity or hypersensitivity reactions.

Adult↗
PubMedDate not supplied

Absolute lymphocyte count as a marker for CD4 T-lymphocyte count: criterion for initiating antiretroviral therapy in HIV infected Nigerians.

BACKGROUND: Few laboratories in resource-constrained countries can afford to perform laboratory-monitoring tests required for the implementation of HIV therapy. In this case control study, we have investigated the relevance of absolute lymphocyte count as a surrogate marker for CD4 lymphocyte count as a criterion for initiating HAARTin HIV-infected Nigerians. METHODS: A total of 100 consecutive recruited HIV-infected, previously antiretroviral naive persons and 30 HIV-negative individuals blood samples were run for absolute lymphocyte and CD4 lymphocyte counts and results were compared by a model of linear regression analysis. RESULTS: An overall modest correlation was observed between absolute lymphocyte count and CD4 lymphocyte (r = 0.51) and at CD4 lymphocyte threshold relevant for clinical management of HIV-infected; <200, 200-350 and >350 cells/microL (r = 0.41, 0.30 and 0.21) respectively. Mean absolute lymphocyte count of 1.60 +/- 0.77 x 10(9)/L, 1.88 +/- 1.11 x 10(9)/L and 2.04 +/- 0.54 x 10(9)/L was equivalent respectively to CD4 of <200, 200-350 and >350 cells/microL. CONCLUSIONS: This study indicates a modest correlation between absolute and CD4 lymphocyte counts of HIV-infected Nigerians and at CD4 lymphocyte count threshold significant for clinical management of HIV-infected. Absolute lymphocyte count can become a minimal inexpensive alternative to CD4 lymphocyte count in conjunction with WHO staging and clinical status of patient in determining the optimal time to initiate therapy particularly in resource limited settings where other expensive methods of CD4 enumeration are unavailable.

Adolescent↗
PubMed1994

Specific western blot bands are associated with initial CD4+ lymphocyte counts in human immunodeficiency virus seroconverters. The Navy HIV Working Group.

The Western blot is the most widely used confirmatory test for determining human immunodeficiency virus (HIV) seropositivity. Specific bands in the Western blot indicate antibody responses to various portions of HIV or its precursors, and each is assigned a score from 0 to 3+. While the precise role of humoral antibody responses has not been fully established, specific antibody responses might influence the course of HIV infection. This study investigated the association between antibody reactivity to nine principal Western blot bands and initial CD4+ counts among 877 Navy and Marine Corps personnel during 1988 to 1991. Multiple regression was used to evaluate the strength and significance of the associations and to adjust for age and estimated duration of infection. Strong antibody responses to the p24 core (P < 0.05), p53 reverse transcriptase (P < 0.005), and p55 core precursor (P < 0.0001) antigens were associated with higher initial CD4+ counts, with 33 to 48 additional cells/mm3 associated with each unit increase in the Western blot score, according to a multiple regression analysis which controlled for age and duration of infection (maximum 24 months). By contrast, antibodies to the gp41 transmembrane antigen (P < 0.0001) were associated with lower initial CD4+ counts. Each unit increase in the gp41 band was associated with 76 fewer CD4+ cells/mm3. A negative association was also observed for the gp160 envelope precursor antigen, with each unit increase in reactivity associated with 51 fewer CD4+ cells, although this association was not statistically significant (P = 0.09).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed2003

Estimation of CD4 T-lymphocyte counts from percent CD4 T-lymphocyte determinations in HIV-1-infected subjects in sub-Saharan Africa.

The relationship between CD4 percent and CD4 count has been reported to be different in industrialized countries compared to sub-Saharan Africa, where often only the former is reliable. CD4 determinations from an open cohort of hotel workers in Dar es Salaam followed between 1990 and 1998 were evaluated. T-lymphocyte determinations were offered once a year to 190 HIV-1 seropositive, 80 seroconverters and 495 sex and age matched HIV-seronegative subjects. After log transformation of the CD4 percent and CD4 counts a good fit to a linear regression curve was found, R(2) 0.697. The CD4 percent corresponding to a CD4 count of 200 cells/mm(3) was found to be 9.8%. CD4 percent determination can be useful to estimate CD4 counts, but needs to be locally standardized. The CD4 percent in Africa corresponding to AIDS defining CD4 counts seems to be lower than in the industrialized world.

Adult↗
PubMed1996

Evolution of tumor necrosis factor-alpha serum concentrations in HIV infected individuals treated with zidovudine.

We studied the evolution of Tumor Necrosis Factor-alpha serum concentration (TNF-alpha) and CD4+ lymphocyte counts (CD4+) in a pilot cohort study of HIV-infected patients during the first year of zidovudine therapy. Data on 17 patients remaining asymptomatic during the one-year follow-up period (non progressors) were analysed. Serum samples were obtained at entry and at each follow-up visit (1, 3, 6, 9 and 12 months). TNF-alpha was quantified in pg/ml using a very sensitive radioimmunoassay (Medgenix). All patients had increased TNF-alpha at entry (median: 26.4 pg/ml). TNF-alpha decreased significantly as soon as the first month of therapy (median: 16 pg/ml). A steady state was then observed until Month 6 (median: 17.5 pg/ml), from which a slow increase appeared, without reaching the initial level (median at Month 9: 21.3, at Month 12: 19.8). During the same time, less sustained changes in CD4+ lymphocytes count and beta-2 microglobulin level were observed. The results of this pilot study suggest that, during HIV infection treated course, TNF-alpha could potentially be an additional surrogate marker to CD4+ lymphocyte count.

Anti-HIV Agents↗
PubMed1998

[Interrelationship between the duration of HIV infection, viral load and CD4 positive lymphocyte count].

BACKGROUND: The decline in CD4+ lymphocytes occurs at different rates in patients with HIV infection. A longer duration of HIV infection and a higher level of viral replication, represented by the viral load, are associated with a lower CD4+ lymphocyte count. However, the interelationship between these variables is still not well known. PATIENTS AND METHODS: 107 HIV-infected patients for whom the date of infection was known, were included in a transversal study, in which the CD4+ lymphocyte count and the plasma viral load were analysed, the last using an isothermal amplification method (NASBA). Patients were not receiving antiretroviral drugs or suffered intercurrent infections at the time of the study. RESULTS: The mean duration of HIV infection was 8.6 +/- 2.9 years. The mean CD4+ lymphocyte count was 366 +/- 264 x 10(6)/l. The mean plasma viraemia was 4.3 +/- 0.9 logs. In a linear regression model, the CD4+ lymphocyte count was explained in 21.7% of cases by the duration of HIV infection, meanwhile the viral load justified up to 36.2 of CD4+ cell variability. When both parameters were combined, up to 58.4% of CD4+ lymphocyte values were explained. In this model, changes of 1 log in viral load had a 4-fold higher effect on the CD4+ cell count than each year of HIV infection. CONCLUSIONS: The duration of HIV infection and, particularly the viral load strongly influences the current CD4+ lymphocyte count, although other variables should exist (virus with syncytium-inducing phenotype, age of the patient and his immunegenetic repertoire) influencing the different decline seen in CD4+ T-cells.

CD4 Lymphocyte Count↗
PubMed1996

CD4 and total lymphocyte counts as predictors of HIV disease progression.

CD4+ T-lymphocyte (CD4) counts are a standard laboratory marker of disease progression in HIV infection, but expense precludes their use in large parts of the world. Total lymphocyte counts (TLC), in contrast, are widely available. We compared CD4 and TLC counts as predictors of developing AIDS or death in 831 HIV-positive out-patients (582 males and 249 females with both homosexual (males, n = 316) and heterosexual (n = 515) transmission patterns. The first CD4 count < 200/microliter and first TLC < 1250/microliter predicted similar (p = 0.52) survival, irrespective of clinical stage. For each clinical stage, a significant difference in progression to AIDS and mortality was predicted by TLC above or below 1250/microliter (p < 0.03). Survival and progression to AIDS occurred at similar rates in patients with a TLC < 1250/microliter or a CD4 count < 200/microliter (p > 0.1), and patients with a TLC > 1250/microliter or a CD4 count > 200/microliter (p > 0.5). A TLC < 1250/microliter preceded the development of Pneumocystis carinii pneumonia or cerebral toxoplasmosis in 76% of patients. In this longitudinal study, TLC and CD4 counts were equal predictors of disease progression. A TLC < 1250/microliter could be considered an indication for commencing cotrimoxazole prophylaxis.

Acquired Immunodeficiency Syndrome↗
PubMed2004

CD4 T-lymphocyte subset counts in HIV-seropositive patients during the course of community-acquired pneumonia caused by Streptococcus pneumoniae.

Total lymphocyte counts, CD4 T-lymphocyte counts and CD4/CD8 ratios were measured in 30 anti-retroviral-naive HIV-seropositive patients upon hospital admission for acute community-acquired pneumonia (CAP) caused by Streptococcus pneumoniae, and again 1 month after resolution of infection. There was a significant depression of the total lymphocyte count (p < 0.005) and CD4 T-lymphocyte count (p < 0.001) in the acute stage of CAP caused by S. pneumoniae, with a subsequent increase in 90% (27/30) of cases after resolution of the infection. There was no significant difference in the CD4/CD8 T-lymphocyte ratio on admission compared with 1 month later (p 0.9).

Adult↗
PubMed1995

[Cellular immune defect caused by postoperative irradiation in patients with squamous epithelial carcinomas of the upper aerodigestive tract].

The effect of locoregional postoperative radiation therapy on cellular immunity was investigated in 11 patients with head and neck cancer. During the course of the radiation therapy, total lymphocyte counts, CD8+ lymphocyte counts and especially CD4+ lymphocyte counts decreased significantly. The mean CD4+ lymphocyte counts dropped from 739/microliters to 183/microliters (p < 0.001) and the average CD4+/CD8+ ratio also decreased significantly. In addition all patients showed impaired in vitro lymphocyte stimulation responses to several mitogens, with reductions found to be 10% to 50% of normal responses. Within 3-4 weeks after radiation therapy there was a slight increase of CD4+ lymphocyte counts and the in vitro lymphocyte stimulation responses showed a tendency to normalization. These results indicate that locoregional postoperative radiation therapy in patients with head and neck cancer can induce a severe impairment of cellular immunity.

CD4 Lymphocyte Count↗