Table 1

Characteristics of the patients with polymyositis/dermatomyositis for serum analysis

Healthy control serum (n = 20)

PM/DM patient serum (n = 29)


Number of PM/DM

7/22

Number of males/females

9/11

9/20

Age (years)

38.6 ± 2.1

55.3 ± 2.5

Duration of the disease (months)

21.6 ± 8.2

Number of cases of new onset/flare

23/6

Number of antinuclear antibody-positive

9 (n = 22)

Number of anti-Jo-1 antibody-positive

8 (n = 22)

Serum creatinine kinase (IU/l)a

4,063.8 ± 1,466.9

Manual muscle testing score

39.0 ± 1.4 (n = 18)

Number of patients with ILD

19

AaDO2 with ILD

31.5 ± 7.9 (n = 19)

Treatment at time of blood sampling

Untreated

19

Prednisolone alone

4

Prednisolone and cyclosporine

5

Prednisolone and methotrexate

1


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 = 17), anti-RNP (n = 13), anti-Scl-70 (n = 4), and anti-SS-A (n = 12) antibodies and rheumatoid factor (n = 16) were analyzed, they were all negative. AaDO2, alveolar-arterial oxygen pressure difference; ILD, interstitial lung disease; 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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