Table 3.

Subjects included in the array.

Feature	Controls	ERA
Children’s of Alabama
N	20	40
Age at diagnosis (years ±SD)	Not applicable	12 ± 3.2
Age at collection (years ±SD)	10.5 ± 4.9	13.2 ± 2.9
Males	11 (55%)	20 (50%)
Race
Caucasian	16 (80%)	29 (72%)
African-American	2 (10%)	11 (28%)
Other	2 (10%)	0 (0%)
HLA-B27+	Not measured	12 / 37 (32%)
Medicines
None	20 (100%)	17 (42%)
Conventional DMARDs alone		6 (15%)
TNFi ± conventional DMARD		17 (42%)
Boston Children’s Hospital
N	18	17
Age at diagnosis (years ±SD)	Notapplicable	11.2 ± 3.4
Age at collection (years ±SD)	14.5 ± 3.6	12.5 ± 3.7
Males	6 (33%)	11 (65%)
Race
Caucasian	13 (72%)	14 (82%)
African-American	2 (11%)	1 (5.9%)
Other	3 (17%)	2 (12%)
HLA-B27+	1/1 (100%)	3/6 (50%)
Medicines	None	None
Cincinnati Children’s Hospital Medical Center
N	24	24
Age at diagnosis (years ± SD)	Not applicable	12.1 ± 2.7
Age at collection (years ± SD)	13.8 ± 3.0	14.0 ± 3.2
Males	18 (75%)	18 (75%)
Race
Caucasian	23 (96%)	22 (92%)
African-American	1 (4.2%)	0
Other		2 (8.4%)
HLA-B27+	Not available	10 / 15 (67%)
Medicines	None	None

Abbreviations: DMARD, disease-modifying anti-rheumatic drugs; TNFi, tumor necrosis factor inhibitor