TABLE 1.
Total fIgA in 26 volunteers before and after challenge with Cryptosporidium oocystsa
| Categoryb | n | fIgA (ng/50 μl)
|
|||||
|---|---|---|---|---|---|---|---|
| Prechallenge
|
Postchallenge (net change)
|
||||||
| Median | Quartiles (Q1, Q3) | P | Median | Quartiles (Q1, Q3) | P | ||
| Dose (oocysts) | |||||||
| >1,000* | 5 | 3.09 | 0.70, 9.87 | 0.245 | 463.10 | 33.00, 537.00 | 0.527 |
| 300–500* | 9 | 8.00 | 2.00, 26.20 | 0.887 | 212.40 | 42.00, 555.00 | 0.943 |
| 30–100 | 12 | 12.64 | 1.20, 39.94 | 150.40 | 34.00, 2,765.00 | ||
| Clinical group | |||||||
| Diarrhea, oocysts** | 12 | 6.02 | 1.66, 26.43 | 0.447 | 214.72 | 53.00, 720.00 | 0.186 |
| Diarrhea, no oocysts** | 3 | 22.98 | 0.00, 70.5 | 0.493 | 50.72 | 27.70, 95.80 | 0.909 |
| Mild/no symptoms, oocysts** | 4 | 18.43 | 4.4, 167.20 | 0.186 | 588.54 | 109.00, 3,785.00 | 0.272 |
| No oocysts or symptoms | 7 | 2.87 | 0.82, 11.89 | 46.45 | 8.00, 600.00 | ||
| Infection | |||||||
| Presumed infected | 19 | 13.38 | 1.40, 29.00 | 0.272 | 212.41 | 52.00, 806.00 | 0.236 |
| Uninfected | 7 | 2.87 | 0.82, 11.89 | 46.45 | 8.00, 600.00 | ||
| Oocysts | |||||||
| Detected | 16 | 10.32 | 1.80, 27.60 | 0.493 | 214.73 | 71.00, 870.00 | 0.073 |
| Not detected | 10 | 5.44 | 0.62, 25.05 | 48.58 | 12.00, 311.00 | ||
| Illness | |||||||
| Diarrhea | 15 | 7.26 | 1.19, 29.00 | 0.836 | 206.10 | 47.00, 464.00 | 0.979 |
| No diarrhea | 11 | 8.00 | 1.40, 23.50 | 212.40 | 13.00, 966.00 | ||
a
Each value represents the amount of total IgA in fecal extracts. Net change for each subject was calculated by subtracting the prechallenge fIgA concentration from the postchallenge sample containing the highest antibody level.
b
Statistical significance determined by Kruskal-Wallis test. *, compared to the 30–100 challenge dose group. **, compared to the no oocysts or symptoms group.