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Table 2 ACPA IgG responses (AU/mL) in 10 plasma and 11 synovial fluid samples “pre” and “post” CCP2 affinity column purification

From: Affinity purified anti-citrullinated protein/peptide antibodies target antigens expressed in the rheumatoid joint

Plasma CCP CEP-1 Cit-vim Cit-fib Cit-C1
Pre Post Pre Post Pre Post Pre Post Pre Post
RA 1 >3,200 >3,200 142 254 <10 45 17 417 17 122
RA 2 505 >3,200 104 1,207 <10 101 18 92 <10 20
RA 3 >3,200 >3,200 44 225 18 59 101 518 333 333
RA 4 >3,200 >3,200 97 1,052 30 65 33 79 77 195
RA 5 >3,200 >3,200 24 30 21 35 104 139 114 172
RA 6 >3,200 >3,200 13 43 30 70 18 36 <10 <10
RA 7 >3,200 >3,200 140 69 107 348 282 155 170 86
RA 8 >3,200 >3,200 11 15 <10 27 42 168 17 26
RA 9 763 >3,200 17 135 <10 59 <10 79 73 222
RA 10 1,151 >3,200 <10 24 <10 47 <10 92 18 38
Median 3,200 3,200 34 102 9 59 25.5 115.5 45.5 104
Synovial fluid CCP CEP-1 Cit-vim Cit-fib Cit-C1
Pre Post Pre Post Pre Post Pre Post Pre Post
RA 11 2,447 >3,200 173 447 31 14 28 163 <10 <10
RA 12 311 1,780 <10 117 15 131 <10 156 <10 <10
RA 13 596 >3,200 15 1,339 19 32 <10 34 <10 185
RA 14 1,196 >3,200 22 109 <10 <10 <10 152 30 18
RA 15 508 >3,200 67 183 <10 191 <10 253 <10 200
RA 16 435 >3,200 16 46 <10 40 <10 <10 <10 111
RA 17 378 1,311 51 610 <10 167 <10 97 <10 44
RA 18 592 1,282 688 900 <10 17 <10 17 <10 48
RA 19 1,084 >3,200 85 339 23 115 17 187 19 62
RA 20 515 1,537 67 1,271 <10 17 <10 21 <10 80
RA 21 566 897 101 900 <10 113 <10 80 <10 146
Median 566 3,200 67a 447a 0 40 0 97 0 62
  1. “Pre” samples were tested at a dilution of 1:100, and “Post” samples were tested at 10 μg/mL. Cutoffs for positivity: 25 AU/mL (CCP) and 10 AU/mL (CEP-1, Cit-vim, Cit-fib, and Cit-C1). aAnti-CEP-1 IgG levels in synovial fluid were significantly higher than the other anti-citrullinated protein/peptide antibody (ACPA) levels (P <0.01). CCP, cyclic citrullinated peptide; CEP-1, citrullinated α-enolase peptide 1 (amino acid 5-21); Cit-C1, citrullinated triple helical peptide/epitope on collagen type II (amino acid 359-369); Cit-fib, citrullinated fibrinogen peptide (β-chain, amino acid 36-52); Cit-vim, citrullinated vimentin peptide (amino acid 60-75); IgG, immunoglobulin G; RA, rheumatoid arthritis.