[1] Western Univ, Schulich Sch Med & Dent, Dept Paediat, London, ON, Canada
[2] London Hlth Sci Ctr, Dept Pathol & Lab Med, London, ON, Canada
[3] Western Univ, Dept Hematol, London, ON, Canada
[4] Western Univ, Schulich Sch Med & Dent, Dept Med, London, ON, Canada
[5] London Hlth Sci Ctr, Div Rheumatol, London, ON, Canada
[6] London Hlth Sci Ctr, Dept Paediat, London, ON, Canada