Histochemical analysis (NSE) and FISH of LTCs from 9 patients with MDS
. | . | . | Long-term marrow cultures . | . | |
|---|---|---|---|---|---|
| Patient no. . | MDS marker chromosome . | % FISH false positive, Mean + 3 SD . | % NSE+ cells . | % FISH+ cells . | |
| 1 | 5q- | 3.8 | 0.9 | 0.5 | |
| 2 | 5q- | 3.8 | 0.0 | 2.3 | |
| 3 | 5q- | 3.8 | 0.5 | 4.1 | |
| 4 | -7 | 3.5 | 5.4 | 1.5 | |
| 5 | 7q- | 5.7 | 7.8 | 2.5 | |
| 6 | 7q- | 5.7 | 4.4 | 2.0 | |
| 7 | +8 | 2.1 | 0.4 | 6.5 | |
| 8 | +8 | 2.1 | 0.8 | 0.5 | |
| 9 | 5q- | 3.8 | 1.4 | 1.0 | |
| -7 | 3.5 | 1.4 | 5.0 | ||
. | . | . | Long-term marrow cultures . | . | |
|---|---|---|---|---|---|
| Patient no. . | MDS marker chromosome . | % FISH false positive, Mean + 3 SD . | % NSE+ cells . | % FISH+ cells . | |
| 1 | 5q- | 3.8 | 0.9 | 0.5 | |
| 2 | 5q- | 3.8 | 0.0 | 2.3 | |
| 3 | 5q- | 3.8 | 0.5 | 4.1 | |
| 4 | -7 | 3.5 | 5.4 | 1.5 | |
| 5 | 7q- | 5.7 | 7.8 | 2.5 | |
| 6 | 7q- | 5.7 | 4.4 | 2.0 | |
| 7 | +8 | 2.1 | 0.4 | 6.5 | |
| 8 | +8 | 2.1 | 0.8 | 0.5 | |
| 9 | 5q- | 3.8 | 1.4 | 1.0 | |
| -7 | 3.5 | 1.4 | 5.0 | ||
The cytogenetic marker specific for the MDS clone from each of 9 patients is listed together with the false-positive rate for the probe used to label that chromosome marker. Each of these background levels was determined with cells from 6 healthy individuals. The macrophage component of the LTC was estimated by the percentage of NSE-positive cells. A previous study showed that NSE is comparable to labeling with CD14 or CD45 for detecting the macrophage component of LTC.5 The data indicate that, with the exception of patient no. 7, the percentage of LTC cells derived from the MDS clone can be accounted for by the combination of macrophages and background levels of the FISH probe. In patient no. 7, we noted an unusual retention of myelocytes in the LTC, which explains the higher percentage of clonally marked cells.