Increase in Normal (Ph−) LTC-IC in 10-Day Cultures of CD34+CD38− CML Blood Cells
| CML No. . | LTC-IC (per 100 input cells)4-150 . | |||||||
|---|---|---|---|---|---|---|---|---|
| . | Day 0 . | Day 10 . | . | . | . | |||
| . | No. . | % Ph− . | No. . | % Ph− . | Expansion . | . | . | . |
| 5a | 18 | 100 (2/2)4-151 | 93 | 100 (11/11) | 5.3 x | |||
| 5b‡ | 2 | 100 (4/4) | <0.03 | — | <0.01 x | |||
| 6 | 102 | 100 (22/22) | 467 | 100 (26/26) | 4.6 x | |||
| 7 | 12 | 100 (17/17) | 47 | 100 (25/25) | 4.1 x | |||
| 8 | 196 | 100 (20/20) | 87 | 100 (1/1) | 0.4 x | |||
| 9 | 2 | 100 (4/4) | <0.0004 | — | <0.0002 x | |||
| CML No. . | LTC-IC (per 100 input cells)4-150 . | |||||||
|---|---|---|---|---|---|---|---|---|
| . | Day 0 . | Day 10 . | . | . | . | |||
| . | No. . | % Ph− . | No. . | % Ph− . | Expansion . | . | . | . |
| 5a | 18 | 100 (2/2)4-151 | 93 | 100 (11/11) | 5.3 x | |||
| 5b‡ | 2 | 100 (4/4) | <0.03 | — | <0.01 x | |||
| 6 | 102 | 100 (22/22) | 467 | 100 (26/26) | 4.6 x | |||
| 7 | 12 | 100 (17/17) | 47 | 100 (25/25) | 4.1 x | |||
| 8 | 196 | 100 (20/20) | 87 | 100 (1/1) | 0.4 x | |||
| 9 | 2 | 100 (4/4) | <0.0004 | — | <0.0002 x | |||
Cells were incubated in a serum-free medium containing FL and SF at 100 ng/mL each, and IL-3, IL-6, and G-CSF at 20 ng/mL each.
All LTC-IC numbers in this study were determined by dividing the total CFC detected in the 6-week-old LTC-IC assay cultures by 8 based on preliminary data suggesting that this represents the average CFC output per Ph+ LTC-IC cultured under the conditions used here (unpublished data, 1996). The corresponding average CFC output from normal cytokine-mobilized LTC-IC is 25.31 Therefore, the values shown in this table may represent overestimates of absolute Ph− LTC-IC frequencies by up to threefold. However, this would be unlikely to affect the expansion values shown because we have previously shown that the CFC output per LTC-IC does not change when normal LTC-IC are expanded in cultures containing the cytokines used here.23
Values shown in parentheses are the numbers of LTC-IC–derived colonies scored as Ph− divided by the total number of LTC-IC–derived colonies analyzed.
b experiment was set up with a separately thawed aliquot of cells from the same patient sample used for the “a” experiment and represents the control (CML cells only) set up in parallel with the mixing experiment reported in Table 6.