title: A new type of temperature-dependent serum M protein: a case of IgG-lambda type multiple myeloma.
abstract: BACKGROUND
  We report a rare case of temperature-dependent serum M protein (thermoprotein), monoclonal IgG(1)-lambda protein isolated from 90-year-old female with advanced multiple myeloma.
  
  
  METHODS
  M protein was identified in the blood plasma of the patient by immunoelectrophoresis (IEP). To evaluate the types of bonds, the properties of the protein after reduction and chemical treatment were examined.
  
  
  RESULTS
  This protein was irreversibly precipitated at or above room temperature when exposed in the air. This protein was redissolved by 30 mmol/l dithiothreitol, 4 mol/l urea, or 8 mmol/l EDTA.
  
  
  CONCLUSIONS
  Unlike other immunoglobulins reported to date, this data suggests that hydrogen, disulfide, and ionic bonds are involved in the temperature-dependent precipitation of this M protein.
authors.affiliation: Department of Central Clinical Laboratory, Kinki University Hospital 377-2, Ohnohigashi, Osakasayama, 589-8511, Osaka, Japan. maimoto@zmail.plala.or.jp
authors.forename: Mayumi
authors.initials: M
authors.lastname: Imoto
authors.forename: Hyogo
authors.initials: H
authors.lastname: Sinohara
authors.forename: Ikunosuke
authors.initials: I
authors.lastname: Sakurabayashi
authors.forename: Tosiyuki
authors.initials: T
authors.lastname: Akiyama
authors.forename: Itaru
authors.initials: I
authors.lastname: Furuta
authors.forename: Takao
authors.initials: T
authors.lastname: Sasaki
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D001798:Blood Proteins / Q000276:immunology*; D001854:Bone Marrow Cells / Q000473:pathology; D004229:Dithiothreitol; D004492:Edetic Acid; D005260:Female; D006801:Humans; D007074:Immunoglobulin G / Q000276:immunology*; D007202:Indicators and Reagents; D009101:Multiple Myeloma / Q000097:blood* / Q000473:pathology; D010084:Oxidation-Reduction
chemical_list: D001798:Blood Proteins; D007074:Immunoglobulin G; D007202:Indicators and Reagents; D004492:Edetic Acid; D004229:Dithiothreitol