Multisite comparison of methods for the quantitation of the surface expression of CD38 on CD8+ T lymphocytes

Abstract

We evaluated the effect of specimen processing variations and quantitation methods on quantitative determination of CD38 expression on CD8 T lymphocytes. Neither lysing reagent (ammonium chloride versus BD FACSlyse), fixation (paraformaldehyde versus no final fixation step), nor acquisition delay (acquisition within 6 h after fixation versus 24 h after fixation) had a significant effect on CD38 relative fluorescent intensity or CD38 quantitative estimates (RFI or antibodies bound per cell). The only significant difference in fluorescent intensity and CD38 antibodies bound per cell (ABC) was encountered when whole blood was held for 24 h prior to staining and fixation and then acquired after another 24‐h hold. However, for all sample processing methods above, the CD4 biologic calibrator and QuantiBRITE bead methods gave significantly different estimates of CD38 intensity. In many cases, however, these differences are relatively small and were more pronounced in certain laboratories. We conclude that there is some flexibility in sample processing methods for quantitative CD38 determination; however, it is preferable for a laboratory to employ one method of fluorescence quantitation calculation consistently because small differences are detected between different methods. Cytometry (Comm. Clin. Cytometry) 42:174–179, 2000. © 2000 Wiley‐Liss, Inc.

Relationship between CD38 expression on peripheral blood T‐cells and monocytes, and response to antiretroviral therapy: A one‐year longitudinal study of a cohort of chronically infected ART‐naive HIV‐1+ patients

“…To ensure consistent instrument set up along the whole longitudinal period of the study, fluorescence detectors/amplifiers were weekly tested for logarithmic amplifier linearity and dynamic range, using Rainbow beads (Spherotech, Libertyville, IL); the same batch of Rainbow beads was used throughout the duration of the study. Compensation settings were adjusted using singly stained (CD8 FITC, CD4 PE) PB samples from healthy donors (32). For data analysis, the Paint-A-Gate PRO software was used; quantitation of CD38 molecules expressed per cell was performed using the QuantiCALC software (BDB) (30).…”

CD38 Expression on CD8+ T Cells as a Prognostic Marker in Vertically HIV-Infected Pediatric Patients

“…This evidence is based predominantly on measurements of %CD8 ϩ CD38 ϩ . The %CD8 ϩ CD38 ϩ and CD8 ϩ (CD38 ϩ ) measurements are highly correlated, but the latter is preferable because of the heterogeneous expression of CD38 on the cell surface (2,6,12,13). This study confirmed that CD38 expression on CD8 ϩ T cells is negatively correlated with age (2, 8, 11) and increased in HIV-infected children in comparison to HIV-uninfected age-matched controls (1,4,5,8,9).…”

“…CD38 is ubiquitously expressed on lymphocytes in a unimodal distribution (9,12). Therefore, in HIV-uninfected or -infected patients, cells that express CD38 are difficult to clearly distinguish from those that do not ( Fig.…”

“…Therefore, in HIV-uninfected or -infected patients, cells that express CD38 are difficult to clearly distinguish from those that do not ( Fig. 1) (12). Quantitating the mean intensity of CD38 expression on CD8 ϩ T cells rather than just the proportion of positive cells (%CD8 ϩ CD38 ϩ ) is preferable and provides a better reflection of the continuous distribution of CD38 on CD8 ϩ T cells (2, 6, 13).…”

Dissociation of CD154 and Cytokine Expression Patterns in CD38+ CD4+ Memory T Cells in Chronic HIV-1 Infection

“…5–7 Particularly, the expression of the activation marker CD38 on CD8 + T cells is a strong predictor of the risk of progression to AIDS, sometimes independently of levels of HIV viremia. 8–15 …”