1. The use of an antigen-binding molecule to eliminate antigen from plasma, where the antigen-binding molecule contains an antigen-binding domain, the antigen-binding activity of which varies depending on ion concentration conditions, and the Fc region in which the amino acid at position 238 is Asp and the amino acid at position 271 is Gly as indicated by EU numbering. 2. The use according to claim 1, wherein the Fc region has an amino acid substitution in at least one or more of the positions selected from the group consisting of 233, 234, 237, 264, 265, 266, 267, 268, 269, 272, 274 , 296, 326, 327, 330, 331, 332, 333, 355, 356, 358, 396, 409 and 419, as indicated by EU numbering. 3. The use of claim 2, wherein the amino acids of the Fc region include any one or more of the following amino acids indicated by EU numbering: Asp at amino acid position 233； Tyr at amino acid position 234； Asp at amino acid position 237； Ile at amino acid position 264； Glu at amino acid position 265； any of Phe, Met and Leu at amino acid position 266； any of Ala, Glu, Gly and Gln at amino acid position 267； any of Asp, Glu and Gln at amino acid position 268； Asp at amino acid position 269； Asp, Phe, Ile, Met, Asn, Pro or Gln at amino acid position 272； Gln at amino acid position 274； Asp or Phe in gender amino acids 296； Ala or Asp at amino acid position 326； Gly at amino acid position 327； Lys or Arg at amino acid position 330； Ser at amino acid position 331； Thr at amino acid position 332； any of Thr, Lys and Arg at amino acid position 333； Gln at amino acid position 355； Glu at amino acid position 356； Met at amino acid position 358； any of Asp, Glu, Phe, Ile, Lys, Leu, Met, Gln, Arg and Tyr at amino acid position 396； Arg at amino acid position 409； and Glu at amino acid position 419.4. The use according to any one of paragraphs. 1-3, where the antigen binding domain is an antigen binding domain, the antigen binding activity of which varies depending on the concentration conditions1
