CRP and immunoglobulin G4-related sclerosing disease: Although age (median 56 years, range 31–83 years) and sex distribution (male to female ratio 11:4) tended to be similar to those for other manifestations of IgG4-RD, the majority of FM patients demonstrated elevated serum CRP (median 2.51 mg/dL, range 0.03–9.68 mg/dL).