CALR and cryoglobulinemia: Most children show positive antinuclear antibodies (ANA) and anti-SSA/Ro, and, to a lesser extent, anti-SSB/La [3, 6–8, 15] and rheumatoid factor (RF) are also frequently found [3, 5–7, 15], while low complement levels and cryoglobulinemia are less frequent [2, 3, 8].