Table 2 Factors associated with serum, sputum, and salivary anti-PAD4 IgG in RA subjects
Serum PAD4+ (N = 6) | Serum PAD4− (N = 31) | p value | Sputum PAD4+ (N = 3) | Sputum PAD4− (N = 34) | p value | Saliva PAD4+ (N = 3) | Saliva PAD− (N = 30) | p value | |
|---|---|---|---|---|---|---|---|---|---|
Age, median (IQR) | 51 (29−64) | 56 (42−60) | 0.71 | 43 (26−59) | 57 (42−61) | 0.27 | 43 (30−59) | 55 (41−61) | 0.33 |
Female | 5 (83) | 22 (71) | 1.0 | 2 (67) | 25 (74) | 1.0 | 2 (67) | 23 (77) | 1.0 |
Non-Hispanic white | 5 (83) | 17 (55) | 0.37 | 2 (67) | 20 (59) | 1.0 | 3 (100) | 18 (60) | 0.28 |
Ever-smoker | 1 (17) | 16 (52) | 0.19 | 1 (33) | 16 (47) | 1.0 | 1 (33) | 13 (43) | 1.0 |
Current smoker | 1 (17) | 6 (19) | 1.0 | 1 (33) | 6 (17) | 0.48 | 1 (33) | 5 (17) | 0.46 |
≥1 shared epitope allele1 | 4 (80) | 19 (70) | 1.0 | 3 (100) | 20 (69) | 0.54 | 2 (100) | 19 (70) | 1.0 |
Chronic lung disease2 | 2 (33) | 7 (23) | 0.62 | 1 (33) | 8 (24) | 1.0 | 1 (33) | 7 (23) | 1.0 |
RA duration >2 years | 4 (67) | 5 (16) | 0.02 | 2 (67) | 7 (21) | 0.14 | 2 (67) | 7 (23) | 0.17 |
Sputum anti-CCP+ | 5 (83) | 13 (42) | 0.09 | 3 (100) | 15 (44) | 0.11 | 3 (100) | 13 (43) | 0.10 |
Sputum anti-CCP level, median (IQR) | 450 (325−753) | 231 (101−603) | 0.09 | 664 (342−1020) | 275 (114−507) | 0.12 | 664 (426−1020) | 252 (114−634) | 0.10 |