IL6 and Increased total leukocyte count: Laboratory evaluation revealed elevated acute phase proteins, including C‐reactive protein (CRP) and ferritin, elevated IL‐6 and soluble IL‐2 receptor (sIL‐2R) in serum, severe anaemia, and leukocytosis with significant monocytosis in the absence of any evidence of infection (Fig 1B and Appendix Clinical Description).