Table 2.
Comparison of serum concentrations of SIgA, total IgA, IgA anti-Chlamydia trachomatis antibodies, and IgA anti-Shigella spp. antibodies between patients and controls.
| Variable | Controls (n = 53) | Patients |
||||
|---|---|---|---|---|---|---|
| Total, n = 46 (p value) | HLA-B27+, n = 22 (p value) | HLA-B27−, n = 24 (p value) | >12 m, n = 24 (p value) | ≤12 m, n = 22 (p value) | ||
| SIgA (g/ml) | ||||||
| Mean ± SD | 10.8 ± 6.5 | 19.8 ± 9.9 (<0.001)a,† | 19.5 ± 11.5 (0.0001)a,† | 20.1 ± 8.6 (<0.001)a,† | 22.9 ± 10.7 (0.001)a,† | 16.7 ± 8.2 (0.0015)a,† |
| Total IgA (mg/dl) | ||||||
| Mean ± SD | 284 ± 107 | 275 ± 123 (0.72)a | 299 ± 140 (0.62)a | 255 ± 106 (0.27)a | 292.7 ± 132 (0.76)a | 257.9 ± 115 (0.349)a |
| IgA anti-C. trachomatis (ratio) | ||||||
| Median [min–max] | 0.44 [0.15–1.75] | 0.55 [0.12–13.03] (0.06)b | 0.46 [0.12–13.03] | 0.59 [0.29–10.4] | 0.67 [0.11–3.57] | 0.45 [0.17–13.0] |
| IgA anti-Shigella spp. (titers) | ||||||
| Median [min–max] | 1/800 [1/200–1/6,400] | 1/800 [1/200–1/6,400] (0.12)b | 1/400 [1/200–1/6,400] | 1/800 [1/200–1/3,200] | 800 [1/200–1/6,400] | 800 [1/200–1/6,400] |
aStudent’s t-test.
bMann–Whitney test.
†Statistical significance, p < 0.05.
HLA-B27+, HLA-B27 allele positive; HLA-B27−, HLA-B27 allele negative; SIgA, secretory immunoglobulin A; >12 m, more than 12 months from diagnosis; <12 m, less than 12 months from diagnosis.