Mercolino TJ, Grenier K, Ward AJ, Bach BA, Borowitz M, Robertson MJ, Recktenwald DJ; International Conference on AIDS.

Int Conf AIDS. 1991 Jun 16-21; 7: 285 (abstract no. W.B.2413).

Becton Dickinson Immunocytometry Systems, San Jose, California, USA

OBJECTIVE: Absolute CD4 count is the most powerful, accepted predictor of clinical HIV disease progression. Current methods for this measurement require multi-step sample preparation and are known to have cumulative errors related to determining both the proportion of CD4 lymphocytes and the absolute lymphocyte count. This study was undertaken to evaluate a flow cytometric assay for the direct determination of absolute CD4 count. METHODS: CD3+ and CD4+ lymphocytes were enumerated on FACScan(TM) flow cytometers, using whole blood samples prepared without erythrocyte lysing or centrifugation. The staining diluent contained a known concentration of fluorescent reference particles and appropriate fluorophore-conjugated monoclonal antibodies. We used fluorescence triggering to identify both stained cells and reference particles. We obtained standard measurements of absolute CD4 counts from % CD4+ cell determinations on a FACScan flow cytometer with lysed whole blood, and absolute counts from an automated three-part differential and WBC (white blood cell) count. RESULTS: We evaluated 12 HIV seronegative and 17 HIV seropositive individuals, using both the current technology (standard WBC/differential and flow cytometry) and the new technique. Correlation coefficients between methods, using linear regression analysis, exceeds 0.96. Moreover, the precision of the new assay exceeded the conventional technique throughout the dynamic range (counts of less than 20/muL to greater than 1400/muL). DISCUSSION AND CONCLUSIONS: Direct flow cytometric, unlysed whole blood determinations of absolute CD4 offer significant advantages over existing technology. These advantages include improved biosafety, speed, and inter- and intra-laboratory precision.

Publication Types:

• Meeting Abstracts

Keywords:

• Acquired Immunodeficiency Syndrome
• CD4-Positive T-Lymphocytes
• Cell Count
• Flow Cytometry
• Fluorescent Antibody Technique
• HIV Infections
• HIV Seropositivity
• Leukocyte Count
• Lymphocyte Count
• methods

Other ID:

• 3241391

UI: 102193043

From Meeting Abstracts