Table 2

Anti-Jo-1 versus other inflammatory myopathies:comparative pathology data

		Anti-Jo-1 myositis				Dermatomyositis			Polymyositis pathology series			Jo-1 negative polymyositis clinical + path				IBM clinical + path			Fasciitis clinical + path
		Anti-Jo-1 myositis				Pathology series			Polymyositis pathology series			Jo-1 negative polymyositis clinical + path				IBM clinical + path			Fasciitis clinical + path		Clinical + path series
		n+	% +			n +	% +		n +	% +		n +	% +			n +	% +		n +	% +	n+	% +
Biopsies (n)	11			18			8		19		8			8			5
Perifascicular myopathy
Atrophic muscle fibres	11	100		18	100		8	100	0	0^2-151	0	0^2-151		0	0^2-151		1	20^***
Myopathic changes^2-152	10	91		12	67		6	75	0	0^2-151	0	0^2-151		0	0^2-151		1	20^2-160
Inflammation (focal)
Perimysial	11	100		7	39^2-151		1	13	3	16^2-151	3	38^***		0	0^2-151		5	100
Endomysial	2	18		4	22		3	37	15	79^2-151	4	50		8	100^2-151		0	0
Perivascular	1	9		12	67^2-160		4	50	13	68^***	5	63^2-150		4	50		2	40
Perimysial connective tissue fragmentation	11	100		3	17^2-151		0	0	3	16^2-151	1	11^2-151		0	0		3	60
Alkaline phosphatase
Perimysial staining	10	91		10	56		2	25	8	42^2-160	3	38^2-150		3	38		1	20^2-160
Small vessel staining	1	9		10	56		5	63	4	21^2-150	2	25		4	50		1	20
COX− muscle fibres
Perifascicular	0	0		11	61^2-150		5	63	0	0	0	0		0	0		0	0
Scattered (>3%)	0	0		0	0		0	0	7	37^2-150	2	25		5^2-151	63		0	0
Capillary index^2-153	0.88 (0.16)						0.55 (0.08)^2-150				0.95 (0.10)						0.88 (0.13)

n+=Number positive; % +=per cent positive; pathological (path) series: pathological changes consistent with diagnosis.
Clinical+path series: definite diagnosis by clinical, laboratory, and pathological criteria.7
Different from Anti-Jo-1 myositis:
↵2-150 p⩽0.05;
↵2-160 p<0.02 ^***; p⩽0.01;
↵2-151 p⩽0.001.
↵2-152 Myopathic changes: muscle fibre necrosis or regeneration
↵2-153 Capillary index (mean (SE)): Capillaries/1000 μm²muscle fibre area; normal =0.85 (0.02).
COX−=cytochrome oxidase negative.