title: [The clinical significance of serum free light chain in primary systemic amyloidosis].
abstract: OBJECTIVE
  To evaluate the diagnostic and therapeutic significance of serum free light chain (sFLC) in primary systemic(AL) amyloidosis.
  
  
  METHODS
  Twenty-five patients with AL amyloidosis, including 18 men and 7 women with a mean age of 54 (47 - 77) years old, were enrolled from October, 2005 to May, 2010. sFLC was measured by immunoturbidimetric assay. The type of monoclonal light chain was judged upon sFLC κ/λ and its sensibility was compared with serum immunofixation and immunohistochemical analysis. Four patients were treated with M(T)D (melphalan/thalidomide,and dexamethasone), one with VD (velcade and dexamethasone) and four with high-dose melphalan followed by autologous stem cell support. The changes of sFLC were serially determined before and after treatment.
  
  
  RESULTS
  Among the 25 patients with AL amyloidosis, two were κ light chains of precursor protein and 23 were λ light chains. Mean plasma cell in bone marrow was 3.5% (0 - 15%). Nineteen (76%) patients had abnormal elevated sFLC and abnormal κ/λ ratios, and 17(68%) patients with immunofixation positive. The sFLC test had similar sensitivity as serum immunofixation (P = 0.727). Twenty-one (84%) patients were shown to have either κ or λ immunoreactive amyloid deposits on biopsied tissues. The sFLC test combined with serum immunofixation allowed the M protein to be detected in 22 (88%) patients. The positive rates of immunohistochemical analysis combined with sFLC test and/or serum immunofixation were 96%. Four patients with hematologic response showed obvious improvement in visceral organ involvement, but illness of 5 patients without hematologic response kept stable or progressed.
  
  
  CONCLUSIONS
  sFLC test is a sensitive qualitative and quantitative method to detect M protein. Preliminary data show the patients with obvious sFLC level decrease and/or κ/λ recovery to normal may have a high percentage of improved organs function. sFLC is critical index in diagnosing AL amyloidosis, which might help efficacy assessment.
authors.affiliation: Department of Hematology, Nanjing General Hospital of Nanjing Military Command, PLA, Nanjing 210002, China. ypzhaicn@yahoo.com.cn
authors.forename: Yong-ping
authors.initials: YP
authors.lastname: Zhai
authors.forename: Ping
authors.initials: P
authors.lastname: Song
authors.forename: Feng
authors.initials: F
authors.lastname: Li
authors.forename: Hai-ning
authors.initials: HN
authors.lastname: Liu
authors.forename: Ya-Ping
authors.initials: YP
authors.lastname: Yu
authors.forename: Xiao-gang
authors.initials: XG
authors.lastname: Zhou
authors.forename: Ping
authors.initials: P
authors.lastname: Shi
authors.forename: Zhi-ming
authors.initials: ZM
authors.lastname: An
authors.forename: Xiao
authors.initials: X
authors.lastname: Zhou
authors.forename: Chun-ni
authors.initials: CN
authors.lastname: Zhang
mesh_terms: D000368:Aged; D000686:Amyloidosis / Q000097:blood* / Q000175:diagnosis / Q000628:therapy; D005260:Female; D006801:Humans; D007147:Immunoglobulin Light Chains / Q000097:blood*; D000075363:Immunoglobulin Light-chain Amyloidosis; D008297:Male; D008875:Middle Aged; D012680:Sensitivity and Specificity; D016896:Treatment Outcome
chemical_list: D007147:Immunoglobulin Light Chains