Genotype distributions of the FcγRIIB 232I/T polymorphism
| FcγRIIB 232I/T polymorphism . | No. (%) . | P, vs healthy controls . | No. (%) . | P, vs healthy controls . | No. (%) . | P, vs healthy controls . | No. (%) . | P . | ||
|---|---|---|---|---|---|---|---|---|---|---|
| Healthy controls, n = 193 . | Total ITP patients, n = 206 . | H pylori–infected ITP patients, n = 100* . | H pylori–uninfected ITP patients, n = 82* . | H pylori eradication therapy† . | ||||||
| Responders, n = 21 . | Nonresponders, n = 21 . | |||||||||
| I/I genotype | 134 (69.4) | 113 (54.8) | .01‡ | 51 (51.0) | .01‡ | 47 (57.3) | .2 | 7 (33.3) | 18 (85.7) | .01‡ |
| I/T genotype | 56 (29.0) | 84 (40.8) | 44 (44.0) | 33 (40.2) | 12 (57.2) | 3 (14.3) | ||||
| T/T genotype | 3 (1.6) | 9 (4.4) | 5 (5.0) | 2 (2.4) | 2 (9.5) | 0 | ||||
| Non-T carriers§ | 134 (69.4) | 113 (54.8) | .003 | 51 (51.0) | .002 | 47 (57.3) | .053 | 7 (33.3) | 18 (85.7) | .001 |
| T carriers§ | 59 (30.6) | 93 (45.2) | 49 (49.0) | 35 (42.7) | 14 (66.7) | 3 (14.3) | ||||
| FcγRIIB 232I/T polymorphism . | No. (%) . | P, vs healthy controls . | No. (%) . | P, vs healthy controls . | No. (%) . | P, vs healthy controls . | No. (%) . | P . | ||
|---|---|---|---|---|---|---|---|---|---|---|
| Healthy controls, n = 193 . | Total ITP patients, n = 206 . | H pylori–infected ITP patients, n = 100* . | H pylori–uninfected ITP patients, n = 82* . | H pylori eradication therapy† . | ||||||
| Responders, n = 21 . | Nonresponders, n = 21 . | |||||||||
| I/I genotype | 134 (69.4) | 113 (54.8) | .01‡ | 51 (51.0) | .01‡ | 47 (57.3) | .2 | 7 (33.3) | 18 (85.7) | .01‡ |
| I/T genotype | 56 (29.0) | 84 (40.8) | 44 (44.0) | 33 (40.2) | 12 (57.2) | 3 (14.3) | ||||
| T/T genotype | 3 (1.6) | 9 (4.4) | 5 (5.0) | 2 (2.4) | 2 (9.5) | 0 | ||||
| Non-T carriers§ | 134 (69.4) | 113 (54.8) | .003 | 51 (51.0) | .002 | 47 (57.3) | .053 | 7 (33.3) | 18 (85.7) | .001 |
| T carriers§ | 59 (30.6) | 93 (45.2) | 49 (49.0) | 35 (42.7) | 14 (66.7) | 3 (14.3) | ||||
Genotype distributions of the FcγRIIB 232I/T polymorphism in ITP patients and healthy controls, in H pylori–infected and –uninfected ITP patients, and in responders and nonresponders to H pylori eradication therapy. Genotype distributions were tested for statistical significance using the χ-square or Fisher exact test when 1 or more variables was <5.
Of 182 patients with ITP evaluated for H pylori infection status, 100 were confirmed positive for H pylori infection based on a positive urea breath test and/or serum anti–H pylori antibodies measured by an enzyme-linked immunosorbent assay kit.
Forty-two H pylori–infected ITP patients were administered amoxicillin (750 mg twice daily), clarithromycin (400 mg twice daily), and lansoprazole (30 mg twice daily) for 7 days. Twenty-one ITP patients were responders, defined as having a platelet count higher than 50 × 109/L and doubling of the baseline level at 24 weeks after initiation of the eradication regimen.
The corrected P (Pcorr) values were calculated by multiplying the observed P value by the number of comparisons made. Pcorr = .03.
FcγRIIB receptors encoded by FcγRIIB 232T are unable to interact with activating receptors and exert inhibitory activity.6,7 In addition, only few subjects were T/T genotype in this study. Therefore, we compared non-T carriers (I/I genotype) to T carriers (I/T + T/T genotype).