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.

Suzuki et al. Arthritis Research & Therapy 2012 14:R48   doi:10.1186/ar3761

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