CRP and immune system disorder: Upon admission, routine autoantibody testing was performed to assess for a comorbid immune disorder, which showed as follow: C-reactive protein (CRP) levels of 0.25 ng/dL, anti-Streptolysin O (ASO) concentrations of 0.25 IU/mL, and rheumatoid factor (RF) levels of <20 IU/mL.