Peptidyl arginine deiminase type IV (PADI4) haplotypes interact with shared epitope regardless of anti-cyclic citrullinated peptide antibody or erosive joint status in rheumatoid arthritis: a case control study

Table 3 Association of PADI4 haplotypes, HLA-DRB1 SE alleles and smoking with susceptibility to erosive and non-erosive RA*

	Controls, No	All RA cases		Erosive RA		Non-erosive RA
Subgroup		No.	OR (95% CI)	No.	OR (95% CI)	No.	OR (95% CI)
GTG-negative†	378	366	1	299	1	67	1
GTG-positive	625	945	1.64 (1.31 to 2.05)	771	1.62 (1.29 to 2.05)	174	1.62 (1.14 to 2.31)
SE-negative	644	429	1	346	1	83	1
SE-positive	359	882	4.31 (3.49 to 5.32)	724	4.45 (3.55 to 5.57)	158	4.16 (2.97 to 5.83)
Non-smoking	856	1,089	1	904	1	185	1
Smoking	134	197	2.28 (1.47 to 3.52)	146	2.01 (1.25 to 3.25)	51	3.83 (2.02 to 7.27)

* Values are the number of subjects. OR and 95% CI for GTG carriage versus non-carriage were adjusted for age, sex, SE alleles and smoking. OR and 95% CI for SE carriage versus non-carriage were adjusted for age, sex, GTG carriage and smoking. OR and 95% CI for smoking versus non-smoking were adjusted for age, sex, GTG carriage and SE alleles. Erosive RA cases were classified as Steinbrocker scores II-IV. RA, rheumatoid arthritis; anti-CCP, anti-cyclic citrullinated peptide autoantibody; OR, odds ratios; CI, confidence intervals.
† Three subjects (two RA patients and one control) who carried ACC and a rare haplotype were excluded from the analysis and hence the GTG-negative subjects carried only ACC/ACC.

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