Table 3.

Histological features, treatment, and biopsy site characteristics of dermatomyositis (DM) patients with and without individual DM autoantibodies. Numbers are percentages unless otherwise indicated.

	Jo1+, n = 13	Jo1–, n = 78	p	TIF1g+, n = 25	TIF1g–, n = 66	p	NXP2+, n = 17	NXP2–, n = 74	p	Mi2+, n = 12	Mi2–, n = 79	p	PM-Scl+, n = 9	PM-Scl–, n = 82	p	MDA5+, n = 5	MDA5–, n = 86	p
Perifascicular atrophy	62	49	0.6	64	45	0.2	53	50	1	67	48	0.4	33	52	0.3	40	51	0.7
Perivascular inflammation	69	60	0.8	64	61	0.8	65	61	1	83	58	0.1	78	60	0.5	20	64	0.1
Primary inflammation	31	22	0.5	12	27	0.2	0	28	0.01	50	19	0.03	67	18	0.004	0	24	0.6
Mitochondrial dysfunction	25	29	1	47	18	0.05	25	29	1	29	28	1	0	30	0.6	50	27	0.5
Necrotizing myopathy	15	17	1	8	20	0.2	18	16	1	8	18	0.7	22	16	0.6	0	17	0.6
Immunosuppressant prior to biopsy	62	61	1	71	57	0.3	44	64	0.2	58	61	1	56	61	0.7	100	58	0.2
Immunosuppressant at biopsy	55	55	1	51	67	0.2	44	58	0.4	50	56	0.8	44	56	0.5	100	53	0.1
Corticosteroids at biopsy	31	49	0.4	58	42	0.2	38	48	0.6	50	45	1	33	48	0.5	80	44	0.2
Days from onset of symptoms to biopsy, median (Q1–Q3)	721 (531–874)	270 (114–497)	0.02	270 (92–561)	293 (128–721)	0.5	125 (66–293)	322 (153–777)	0.01	163 (58–402)	304 (128–663)	0.1	232 (114–1880)	293 (118–605)	0.9 (296–637)	403 (114–615)	288	0.4
Deltoid biopsy	36	42	1	60	34	0.06	20	45	0.2	29	43	0.7	14	44	0.2	50	41	1
Biceps biopsy	9	7	1	0	10	0.3	20	5	0.1	0	8	1	0	8	1	0	8	1
Quadriceps biopsy	55	51	1	40	56	0.3	60	50	0.7	71	49	0.4	86	48	0.1	50	51	1

Significant data indicated in bold face. TIF1-γ: transcriptional intermediary factor 1-γ.