title: Higher serum clozapine level is associated with increased antiphospholipid antibodies in schizophrenia patients.
abstract: OBJECTIVE
  This study was to evaluate the relationship between clozapine and aPL in schizophrenia patients.
  
  
  METHODS
  163 Participants were evaluated: 37 unmedicated schizophrenia patients, 50 clozapine-treated schizophrenia patients and 76 age- and sex-matched healthy controls. A fasting blood sample was taken for serum aPL and serum clozapine level. Serum aPL were measured by ELISA technique and HPLC method was used for the determination of serum clozapine level.
  
  
  RESULTS
  The unmedicated schizophrenia patients showed higher IgG aCL level [mean+/-SD: 1.51+/-0.81 and 1.25+/-0.13 U, respectively (t=2.77, df=111, p<0.01)] and IgM aCL level [mean+/-SD: 1.53+/-0.54. and 1.33+/-0.15 U, respectively (t=-2.98, df=111, p<0.01)] compared with the healthy controls. The comparison of the clozapine-treated schizophrenia patients and the healthy controls showed significant difference in IgG aCL level [mean+/-SD: 1.74+/-0.90 and 1.25+/-0.13 U, respectively (t=-4.77, df=124, p<0.01)] and IgM aCL level [mean+/-SD: 1.62+/-0.83 and 1.33+/-0.15 U, respectively (t=-4.35, df=124, p<0.01)]. In clozapine-treated schizophrenia patients, the results of Pearson correlation coefficients showed that there was a significant positive relationship between serum IgM aCL and serum clozapine level (r=0.461, p<0.01), and serum IgG aCL were significantly correlated with serum IgM aCL (r=0.279, p<0.05). Stepwise multiple regression analysis was performed with various characteristics, such as duration of medication, daily dose and serum clozapine level as candidate factors for serum aCL (IgG and IgM isotypes) in clozapine-treated schizophrenia patients. Only serum clozapine level was able to enter into the regression model of IgM aCL (Model R(2)=0.212, p<0.05).
  
  
  CONCLUSIONS
  A higher serum clozapine level is associated with an increased aPL in schizophrenia patients.
authors.affiliation: Neuro-psychiatric Institute, Nanjing Brain Hospital Affiliated to Nanjing Medical University, 264 Guangzhou Road, Nanjing 210029, China.
authors.forename: Hong
authors.initials: H
authors.lastname: Shen
authors.forename: Rui
authors.initials: R
authors.lastname: Li
authors.forename: Hong
authors.initials: H
authors.lastname: Xiao
authors.forename: Qun
authors.initials: Q
authors.lastname: Zhou
authors.forename: Qing
authors.initials: Q
authors.lastname: Cui
authors.forename: Jianfang
authors.initials: J
authors.lastname: Chen
mesh_terms: D000328:Adult; D017152:Antibodies, Antiphospholipid / Q000097:blood*; D014150:Antipsychotic Agents / Q000097:blood*; D002851:Chromatography, High Pressure Liquid / Q000379:methods; D003024:Clozapine / Q000097:blood*; D004797:Enzyme-Linked Immunosorbent Assay / Q000379:methods; D005260:Female; D006801:Humans; D007074:Immunoglobulin G / Q000097:blood; D007075:Immunoglobulin M / Q000097:blood; D008297:Male; D008875:Middle Aged; D012559:Schizophrenia / Q000097:blood*; D055815:Young Adult
chemical_list: D017152:Antibodies, Antiphospholipid; D014150:Antipsychotic Agents; D007074:Immunoglobulin G; D007075:Immunoglobulin M; D003024:Clozapine