Calculated pI of combined CDRs (CDR1⁺CDR2⁺CDR3) in κ LCs from LCDD or control patients. Blood pH is indicated by the red line. Control LCs were from patients with AL amyloidosis (green dots) and Fanconi syndrome (blue dots). There was no difference between the 2 control groups (not shown). ****P < .0001 (Mann-Whitney U test).