Complement system in bipolar disorders and schizophrenia: C3 and C4

  • Dr Brisa Fernandes, Bipolar Disorder Program and Laboratory of Molecular Psychiatry, Hospital de Clínicas de Porto Alegre, Brazil, and INCT for Tra, Brazil
  • Dr Kelia Cereser, Bipolar Disorder Program and Laboratory of Molecular Psychiatry, Hospital de Clínicas de Porto Alegre, Brazil, and INCT for Tra, Brazil
  • Karine Zortea, Bipolar Disorder Program and Laboratory of Molecular Psychiatry, Hospital de Clínicas de Porto Alegre, Brazil, and INCT for Tra, Brazil
  • Gabriel Fries, Bipolar Disorder Program and Laboratory of Molecular Psychiatry, Hospital de Clínicas de Porto Alegre, Brazil, and INCT for Tra, Brazil
  • Gabriela Colpo, Bipolar Disorder Program and Laboratory of Molecular Psychiatry, Hospital de Clínicas de Porto Alegre, Brazil, and INCT for Tra, Brazil
  • Laura Moreira, Hospital de Clínicas de Porto Alegre, Brazil
  • Dr Flavio Kapczinski, Hospital de Clínicas de Porto Alegre, Brazil
  • Dr Clarissa Gama, Hospital de Clínicas de Porto Alegre, Brazil, and INCT for Tra, Brazil

Introduction: Although abnormalities of the immune system have been described in depression, information on serum alterations in Bipolar Disorder (BD) and Schizophrenia (SZ) has been scarce. Complement is a major effector system of innate immunity, and it lyses and opsonizes necrotic or apoptotic cells. The complement system is activated by the classical, alternative and lectin pathways. The aim of the present study was to examine the serum levels of C3 and C4 in patients with schizophrenia and bipolar disorder compared to healthy subjects.
Methods: We assessed serum C3 and C4 in 20 patients with BD in euthymia and 20 in mania, 52 patients with schizophrenia and 80 healthy controls. All patients were assessed by SCID-I. C3 and C4 were measured by nephelometry.
Results: The mean sample age was 40.70 ± 11.74. Eighty-eight subjects were male (51.20%). C3 was increased in patients with SZ when compared either to manic and euthymic patients or controls (189.03 ± 44.20, 16.00 ± 43.52, 162.47 ± 31.83 and 162.60 ± 50.06, respectively, p=0.006 for SZ versus control). There was no difference in C4 (39.52 ± 16.31, 34.88 ± 15.59, 33.14 ± 10.54 and 38.41 ± 24.89, for SZ, mania, euthymia and controls, respectively, p=0.63).
Conclusions: in this study, we found an activation of the complement system in SZ but not in BD during mania and euthymia. An increase in C3 but not in C4 suggests that the activation of the complement system occurs by the alternative pathway.