Serum level of soluble CX3CL1/fractalkine is elevated in patients with polymyositis and dermatomyositis, which is correlated with disease activity

Table 2 Characteristics of the patients with polymyositis/dermatomyositis for muscle and lung analysis

	PM/DM patients (n= 11)
	Muscle (n= 5)	Lung (n= 6)
Number of PM/DM	2/3	3/3
Number of males/females	2/3	1/5
Age (years)	60.4 ± 5.3	59.8 ± 4.3
Duration of the disease (month)	17.6 ± 13.4	20.8 ± 13.2
Number of cases of new onset/flare	4/1	3/3
Number of antinuclear antibody-positive	1 (n = 4)	1 (n = 5)
Number of anti-Jo-1 antibody-positive	0 (n = 4)	1 (n = 5)
Serum creatinine kinase (IU/l)^a	2,946.4 ± 1,195.4	141.4 ± 57.4 (n = 5)
Manual muscle testing score	54.3 ± 5.8 (n = 4)	NA
Number of patients with ILD	4	6
AaDO₂ with ILD	NA	22.7 ± 6.6 (n = 5)
Treatment at time of biopsy
Untreated	4	4
Prednisolone alone	0	2
Prednisolone and cyclosporine	1	0

Data presented as n or mean ± standard error of the mean. Antinuclear antibody was analyzed by immunofluorescence assay. The titer of anti-Jo-1 antibody was investigated by enzyme immunoassay. Although in some patients, anti-dsDNA (n = 1 and n = 2 for muscle and lung samples, respectively), anti-RNP (n = 1 and n = 2), anti-Scl-70 (n = 1 and n = 2), and anti-SS-A (n = 1 and n = 4) antibodies and rheumatoid factor (n = 2 and n = 4) were analyzed, they were all negative. AaDO₂, alveolar-arterial oxygen pressure difference; ILD, interstitial lung disease; NA, not available; PM/DM, polymyositis/dermatomyositis. ^aNormal range: male < 197 IU/l, female < 180 IU/l.

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