Table 2

Characteristics of musculoskeletal IRAEs, laboratory and imaging results

Patient	Pattern of arthritis	PMR-like disease	Other MS IRAEs	Latency of MS IRAEs after ICI start (days)	CRP at onset of MS IRAEs (mg/L)	RF/anti-CCP	ANA/ENA	HLA-B27	Synovial fluid cell counts (cells/µL)	Proof of MSI on imaging: US (1), PET-CT (2), CT (3), MRI (4)
1	Oligo	+ve	−ve	174	9.9	−ve /−ve	−ve /−ve	−ve	12 300	1
2	Mono	−ve	−ve	121	≤5.0	−ve /−ve	1:100/ ND	ND	ND	3, 4
3	Mono	+ve	Sicca	289	5.5	−ve /−ve	−ve / ND	−ve	ND	1, 4
4	Poly	+ve	−ve	1	9.8	+ve/+ve	1:400/−ve	ND	ND	1,2,3
5	Poly	+ve	−ve	48	38.6	−ve /−ve	1:3200/ −ve	−ve	ND	1
6	Oligo	−ve	−ve	143	38.2	−ve /−ve	1:1600/−ve	ND	ND	1
7	Oligo	−ve	Sicca	43	71.3	−ve /−ve	−ve / ND	−ve	2600	1
8	Mono	−ve	−ve	31	21.2	−ve /−ve	1:800/−ve	−ve	ND	2
9	Mono	−ve	−ve	716	≤5.0	−ve/−ve	1:200/−ve	−ve	ND	2, 3, 4
10	Mono	−ve	−ve	253	≤5.0	+ve/ ve	1:100/ ND	ND	ND	1, 4
11	Oligo	−ve	Myositis	76	≤5.0	−ve/−ve	−ve / ND	−ve	20 000	1, 2, 3
12	Mono	−ve	−ve	139	6.8	+ve/−ve	1:400/−ve	−ve	ND	4
13	Oligo	−ve	−ve	116	48	+ve/−ve	1:12800/ SSA	−ve	6000	1, 2, 3
14	Mono	+ve	−ve	394	114	+ve/−ve	−ve /−ve	−ve	ND	1

MRI (hyperintensity on STIR images and/or prominent contrast enhancement on postcontrast fat-suppressed T1-weighted images).
ANA, antinuclear autoantibodies; anti-CCP, anti-cyclic citrullinated peptide antibodies; CRP, C reactive protein; ENA, extractable nuclear antigens; ICI, immune checkpoint inhibitor; IRAEs, immune-related adverse events; HLA, human leukocyte antigen; MS, musculoskeletal; MSI, musculoskeletal inflammation; ND, not determined; PET-CT, positron emission tomography-CT; PMR , polymyalgia rheumatica with ultrasound features including bursitis or tenosynovitis of shouldersor hips typical for PMR; RF, rheumatoid factor; Sicca, proven by Saxon and Schirmer test; SSA, anti-Sjögren’s syndrome-related antigen antibodies; US, ultrasound (proof of synovitis: ≥ grade 2 grey scale or ≥ grade 1 power Doppler findings); +ve, if positive; −ve, if negative.