| Hp phenotypes | N | Average (cells/mm3) | Standard deviation | p-value (Kruskal-Wallis) |
| 1-1 | 270 | 471 | 144 | 0.89 |
| 2-1 | 330 | 470 | 149 | |
| 2-2 | 227 | 469 | 149 | |
| 0-0 | 8 | 450 | 208 | |
| Total | 835 | 465 | 147 |
|