C4A and cryoglobulinemia: The rheumatology-targeted workup was significant for positive anti-Ro (SSA) antibody (> 8) (reference level: < 1), RF, elevated beta-2-microglobulin, cryoglobulinemia (level not quantitated), hypocomplementia (C3 < 83 [reference range 88–165] mg/dL; C4 < 8 [reference range 14–44] mg/dL), elevated inflammatory makers (erythrocyte sedimentation rate > 140 mm/hour; C-reactive protein = 44 mg/L), negative ANA, and monoclonal gammopathy of unknown significance (κ = 43.4 [reference range 0.33–1.94] mg/dL; λ = 31.1 [reference range 0.57–2.63] mg/dL; κ/λ =  1.4).