Correction: The PTPN22 1858C/T polymorphism is associated with anti-cyclic citrullinated peptide antibody-positive early rheumatoid arthritis in northern Sweden

After publication of our recent article [1], we noticed an error in Table 6 'Relative risk for developing rheumatoid arthritis in patients, stratified for anti-cyclic citrullinated peptide (anti-CCP) antibodies'.

Under the heading of 'Anti-CCP antibody-positive', the first line should read 'HLA-shared epitope-negative', and the second line should read 'HLA-shared epitope-positive'. Similarly, under the heading 'Anti-CCP antibody-negative', the first line should read 'HLA-shared epitope-negative' and the second line should read 'HLA-shared epitope-positive'.

The correct table is given here as Table 1 (a corrected version of Table 6 [1]).

Table 1.

Relative risk for developing rheumatoid arthritis in patients, stratified for anti-cyclic citrullinated peptide (anti-CCP) antibodies

	Nonsmoking		Smoking
	Cases/controls	Relative risk (95% confidence interval)	Cases/controls	Relative risk (confidence interval)
Anti-CCP antibody-positive
HLA-shared epitope-negative	33/41	1.00	71/49	1.67 (0.95–2.94)
HLA-shared epitope-positive	62/33	2.05 (1.12–3.75)	143/21	7.61 (4.05–14.30)
Anti-CCP antibody-negative
HLA-shared epitope-negative	40/41	1.00	52/49	1.11 (0.63–1.95)
HLA-shared epitope-positive	23/33	0.71 (0.37–1.38)	31/21	1.92 (0.98–3.77)

The combination of carriage of HLA-shared epitope alleles or not, and ever or never smoking were compared for groups stratified for anti-CCP antibodies.

See related research article by Kokkonen et al., http://arthritis-research.com/content/9/3/R56