Table 4 Phenotypic features of children who are ACPA and RF positive versus those ACPA positive and RF negative

Males, N

8

2 (8 %)

<0.03

Onset age, years

4.6

12.1

<0.0001

Mean RF IgM titer, units

6

129

<0.0001

Mean RF IgG titer, units

7

34

0.007

Mean RF IgA titer, units

6

161

<0.0001

Mean ACPA titer, units

33

282

<0.0001

HLA-DR SE positive N (%)

9/21 (43%)

18/21 (86%)

<0.003

ILAR Subtypes

Persistent oligoarthritis

4

0

-

Extended oligoarthritis

5

0

-

RF - polyarthritis

6

0

-

RF + polyarthritis

0

22

-

ERA

1

0

-

Systemic JIA

4

0

-

Undifferentiated JIA

2

3

-