Supplementary Table 1.

Characteristics of 20 patients whose pre- and post-RTX data were available

Male sex, n (%)	12 (60.0)
Age at first RTX infusion, mean (SD), years	61.5 (5.8)
RA disease duration at first RTX, median (Q1-Q3), years	12.2 (4.4-19.8)
ILD disease duration at first RTX, median (Q1-Q3), years	2.6 (0.1-5.2)
Age at RA diagnosis, mean (SD), years	48.6 (13.2)
Age at ILD diagnosis, mean (SD), years	58.1 (7.0)
RF positivity, n (%)	19 (95.0)
ACPA positivity*, n (%)	15 (88.2)
ANA positivity†, n (%)	9 (47.4)
Higher CRP (> 5 mg/L), n (%)	14 (70.0)
CRP levels,mg/L, mean (SD)	40.3 (58.9)
Higher ESR (>20 mm/hour), n (%)	16 (80.0)
ESR levels, mean (SD)	37.7 (18.2)
Smoking status, n (%)
Never	6 (30.0)
Ex-smoker	12 (60.0)
Current	2 (10.0)
Secondary Sjögren’s syndrome, n (%)	1 (5.0)
Prior anti-TNF treatment, n (%)	4 (20.0)
Concomitant DMARDs
Methothrexate	1 (5.0)
Azathioprine	1 (5.0)
Leflunomide	9 (45.0)
Mycophenolate mofetil	2 (10.0)
Steroids	18 (90.0)
DAS28 at first RTX infusion, mean (SD)	5.1 (1.5)
Radiographic pattern, n (%)
Usual interstitial pneumonia	10 (50.0)
Non-specific interstitial pneumonia	7 (35.0)
Organizing pneumonia	2 (10.0)
Indeterminate	1 (5.0)
Median pre-RTX DLCO ¥ , %, (Q1-Q3)	71 (54-79)
Median pre-RTX FVC § , %, (Q1-Q3)	79 (64-100)
Follow-up duration, median (Q1-Q3), years	2.7 (2.1-3.8)

RA= rheumatoid arthritis, ILD= interstitial lung disease, RTX= rituximab, RF= romatoid factor, ACPA= anti-citrullinated protein antibody, CRP= C reactive protein, ESR= erythrocyte sedimentation rate, anti-TNF= anti tumor necrosis factor, DMARDs= disease-modifying antirheumatic drugs, DAS28= disease activity score 28, DLCO= diffusion capacity of carbon monoxide, FVC= forced vital capacity

*Data of 17 patients were available, †Data of 19 patients were available, ^¥Data of 15 patients were available, ^§Data of 13 patients were available