Table 1.

IgG anti-citrullinated HSP90 antibodies in BALF.

	citHSP90αa	citHSP90βa	PP 1C–5Cb	PP 6C–10Cb
RA-ILD (n = 8)	0	1c	3d	0
RA-subILD (n = 5)	2	0	1e	0
RA-no ILD (n = 8)	0	0	1f	1
IPF (n = 5)	0	0	0	0
Healthy control (n = 5)	0	0	0	0

RA-ILD = RA with ILD, RA-subILD = RA with subclinical ILD (absence of cough, dyspnea), RA-no ILD = RA without ILD, IPF = idiopathic pulmonary fibrosis.

^aPositive responses based on relative ratio of OD₄₅₀ reading compared to that of standard reference serum, using recombinant citrullinated HSP90α or citrullinated HSP90β as substrate antigen (1 µg/ml).

^bPositive responses based on relative ratio of OD₄₅₀ reading compared to that of standard reference serum, using peptide pools (PP) consisting of 1C–5C or 6C–10C (5 peptides/pool, each at 0.2 µg/ml) as substrate antigens.

^cSample also positive for uncitrullinated HSP90β and PP 1C–5C.

^d2/3 samples with similar level of response to uncitrullinated peptide pool 1–5.

^eSample also positive for citHSP90α.

^fSimilar level of response to uncitrullinated peptide pool 1–5.