Table 4.
Regulation of immunopathology in human trialsa
| Disease | Parasite treatment (regimen) | No. of subjects | Effect(s) | Reference(s) |
|---|---|---|---|---|
| Allergic rhinitis | Trichuris suis (2,500 ova every 3 wk for 24 wk) | 96 (49 infected, 47 placebo) | No change in clinical disease | 19 |
| Allergic rhinoconjuctivitis | Necator americanus (10 larvae) | 30 (15 infected, 15 placebo) | No clinical benefit; no suppressive immune response or reduction of allergic immune response | 30, 84 |
| Celiac disease | Necator americanus (15 larvae total) | 20 (10 infected, 10 placebo) | No clinical benefit; suppression of intestinal inflammatory cytokines | 61, 191 |
| Crohn's disease | Necator americanus | 9 (all infected) | Trend toward reduced disease; CDAI at baseline, 165; CDAI at wk 20 postinfection, 64 (P = 0.132) | 58 |
| Crohn's disease | Trichuris suis (2,500 ova every 3 wk for 24 wk) | 29 (all infected) | Significant suppression of pathology; 79.3% response, 72.4% remission | 270 |
| Crohn's disease and ulcerative colitis | Trichuris suis (2,500 ova initially, boosts of 2,500 ova every 3 wk) | CD, 4 infected, 2 given boost; UC, 3 infected, 2 given boost | CD, 3/4 patients entered remission; UC, 3/3 improved (mean, 43% improvement) | 269 |
| Ulcerative colitis | Trichuris suis (2,500 ova every 2 wk for 12 wk) | 52 (29 infected, 23 placebo) | Significant suppression of pathology; UCDAI, 8.75–7.5 for placebo (P = 0.1167), 8.77–6.1 for infected (P = 0.0004); simple index, no change for placebo (P > 0.05), decrease for infected (P < 0.0001) | 271 |
| Ulcerative colitis | Trichuris trichiura (500, 1,000, and 200 eggs) | 1 (infected) | Disease remission after infection; downregulation of mucosal inflammatory cytokines; switch to IL-22 | 36 |
| Multiple sclerosis | Various (3 Hymenolepis nana, 3 Trichuris trichiura, 3 Ascaris lumbricoides, 2 Strongyloides stercolaris, 1 Enterobius vermicularis) | 24 (12 infected, 12 matched controls) | Significantly fewer exacerbations when infected; drug cure of 4 patientsb led to increase of symptoms to uninfected control levels; MARR, 0 for infected, 1.09 for uninfected (P < 0.0001); increase after drug cure, P = 0.007; decreased inflammatory cytokine levels, increased IL-10, TGF-β, and Treg levels with parasitic infection | 55–57 |
| Multiple sclerosis | Trichuris suis ova (2,500 ova every 2 wk for 24 wk) | 5 (all infected) | Trend toward reduced disease; no change in peripheral Tregs or alternatively activated macrophages | 26, 89 |
a
CDAI, Crohn's disease activity index; CD, Crohn's disease; UC, ulcerative colitis; UCDAI, ulcerative colitis disease activity index; MARR, median annual relapse rate.
b
Two patients were infected with A. lumbricoides, 1 was infected with T. trichiura, and 1 was infected with S. stercolaris.