TABLE 7.
Differences and correlations between fresh and cryopreserved PBMC flow cytometric enumeration of CD4+ and CD8+ T-cell subpopulations
| Phenotype | No. of subjects per lab | Median % in fresh (frozen) PBMC | Median difference (%) (range) between fresh and frozen PBMCa | Median (range) of correlation coefficientb | No. (%) of labs with significant correlationsc |
|---|---|---|---|---|---|
| CD4+ CD45RA+ CD95− | 11-18 | 36 (34) | −3.0 (−6.0-4.0) | 0.90 (0.51-0.94) | 6 (86) |
| CD4+ CD28+ CD95− | 11-12 | 37 (41) | −3.0 (−8.0-−0.6) | 0.87 (0.76-0.93) | 7 (100) |
| CD4+ CD28+ CD95+ | 11-12 | 57 (52) | 5.7 (−1.4-6.5) | 0.90 (0.81-0.94) | 7 (100) |
| CD4+ CD38+ HLADR+ | 4-12 | 7 (7) | 0.0 (−2.0-1.0) | 0.73 (0.52-0.76) | 5 (83) |
| CD4+ CD45RA+ CD62L+ | 2-8 | 35 (22) | 11.0 (6.0-14.5) | 0.47 (−1.0-0.70) | 0 |
| CD3+ CD4+ CD45RO+ | 3-8 | 18 (15) | 3.0 (−6.0-12.0) | 0.32 (−1.0-1.0) | 0 |
| CD8+ CD28+ CD95− | 3-8 | 7 (10.0) | −1.0 (−9.5-8.0) | 0.65 (0.12-0.92) | 2 (40) |
| CD8+ CD28+ CD95+ | 3-8 | 25 (23) | 1.1 (−2.0-12.0) | 0.74 (−0.50-1.0) | 2 (40) |
| CD8+ CD38+ HLADR+ | 13-20 | 33 (25) | 6.5 (3.0-12.0) | 0.85 (0.76-0.93) | 7 (100) |
Differences of the indicated phenotype in fresh versus frozen PBMC were calculated by subtracting the percentage of the indicated phenotype in cryopreserved PBMC from the percentage of the phenotype in fresh PBMC. The data represent the median difference across all laboratories and the range of median differences at individual laboratories.
Spearman correlation analysis of fresh and frozen PBMC in each laboratory was used to generate a coefficient of correlation. The data indicate the median and the range of medians of the coefficient of correlations at individual laboratories.
Significance, defined by P ≤ 0.05, was calculated only for laboratories that tested PBMC from five or more donors.