Specificity of the hypersensitivity to PEG-rHu MGDF in ET: sensitivities of nonadherent healthy and ET megakaryocytic progenitor cells to various cytokines
| Titrated cytokine . | Fixed cytokine5-150 . | Conc. of cytokine at 1/2 max. colony no. (ng/mL) . | ||
|---|---|---|---|---|
| N . | ET . | Sensitivity ratio5-151 . | ||
| IL-3 alone | 4.4 | 3.4 | 1.3× | |
| IL-3 | MGDF | 4.3 | 3.9 | 1.1× |
| SCF alone | 28 | < 20 | > 1.4× | |
| SCF | MGDF | 32 | 21 | 1.5× |
| GM-CSF alone | 5 | 3.8 | 1.3× | |
| GM-CSF | IL-3 | nr | 1.1 | — |
| MGDF alone | 0.0-0.2 | 0.2-0.6 | — | |
| MGDF | IL-3 | 40 | < 0.10 | > 250× |
| Titrated cytokine . | Fixed cytokine5-150 . | Conc. of cytokine at 1/2 max. colony no. (ng/mL) . | ||
|---|---|---|---|---|
| N . | ET . | Sensitivity ratio5-151 . | ||
| IL-3 alone | 4.4 | 3.4 | 1.3× | |
| IL-3 | MGDF | 4.3 | 3.9 | 1.1× |
| SCF alone | 28 | < 20 | > 1.4× | |
| SCF | MGDF | 32 | 21 | 1.5× |
| GM-CSF alone | 5 | 3.8 | 1.3× | |
| GM-CSF | IL-3 | nr | 1.1 | — |
| MGDF alone | 0.0-0.2 | 0.2-0.6 | — | |
| MGDF | IL-3 | 40 | < 0.10 | > 250× |
Cell number plated: 4 × 104/0.1 mL culture throughout.
ET, essential thrombocythemia; MGDF, megakaryocyte growth and development factor; SCF, stem cell factor; GM-CSF, granulocyte-macrophage colony-stimulating factor; IL-3, interleukin 3; nr, nonresponsive.
Concentration of fixed cytokine, MGDF: 100 ng/mL; IL-3: 10 ng/mL.
Sensitivity ratio = conc. of cytokine at half max. colony no. N/ET = no. of times normal.