Summary of preclinical systemic immune effects of I-Quit-Ordinary-Smoking (IQOS) compared with sham and 3R4F research cigarettes
| Parameter | Sham (n=8–10) | IQOS (n=7–9) | 3R4F (n=9–10) |
| Blood neutrophil count (109/L) | 1.3 (0.3) | 4.8 (2.1)* | 2.7 (0.4)* |
| Thymus weight | 4.0 (0.4) | 2.6 (0.6)* | 2.5 (0.3)* |
| Histological thymic atrophy score | 0.1 (0.1) | 1.8 (0.4)* | 1.1 (0.4)* |
Unless otherwise specified, results signify those from male rats at the highest nicotine exposure levels for each group.
*Significantly different compared with sham; statistical comparisons between IQOS and 3R4F were not reported for blood neutrophil count or thymic atrophy score.