title: Association of serum complement (C3, C4) and immunoglobulin (IgG, IgM) levels with hormone replacement therapy in healthy post-menopausal women.
abstract: BACKGROUND
  Recently published data suggest that hormone replacement therapy (HRT) may increase cardiovascular risk during the early months of therapy. Activation of the immune system is known to be involved in several types of cardiovascular disease. In this cross-sectional study, serum C3, C4, IgG and IgM levels were evaluated in healthy post-menopausal women receiving two different short-term HRT regimens, and in untreated women.
  
  
  METHODS
  Serum C3, C4, IgM and IgG levels were assessed in 18 women receiving transdermal 17beta-estradiol (50 micro g/day) + continuous oral medroxyprogesterone acetate (MPA; 2.5 mg/day), in 56 women taking oral conjugated equine estrogen (CEE; 0.625 mg/day) + continuous MPA, and in 80 control women not receiving HRT.
  
  
  RESULTS
  The mean serum C3 level was significantly higher in women using oral CEE + MPA than in women receiving transdermal 17beta-estradiol + MPA, and those not on HRT (P = 0.02 and P < 0.001 respectively). Furthermore, women taking oral CEE + MPA had significantly higher mean levels of C4 compared with untreated women (P < 0.01). IgG and IgM levels were similar among women either of the two HRT regimens and between women not on HRT.
  
  
  CONCLUSIONS
  Oral HRT may be involved in the development of cardiovascular disease through inflammatory mechanisms, as suggested by increased serum levels of C3 and C4.
authors.affiliation: Department of Obstetrics and Gynecology, Afyon Kocatepe University, Faculty of Medicine, Afyon, Turkey. meyilmazer@hotmail.com
authors.forename: Mehmet
authors.initials: M
authors.lastname: Yilmazer
authors.forename: Veysel
authors.initials: V
authors.lastname: Fenkci
authors.forename: Semin
authors.initials: S
authors.lastname: Fenkci
authors.forename: Orhan
authors.initials: O
authors.lastname: Aktepe
authors.forename: Murat
authors.initials: M
authors.lastname: Sonmezer
authors.forename: Gulay
authors.initials: G
authors.lastname: Kurtay
mesh_terms: D000328:Adult; D002318:Cardiovascular Diseases / Q000453:epidemiology / Q000276:immunology; D003176:Complement C3 / Q000378:metabolism*; D003181:Complement C4 / Q000378:metabolism*; D003271:Contraceptive Agents, Female / Q000008:administration & dosage; D003430:Cross-Sectional Studies; D004958:Estradiol / Q000008:administration & dosage; D015914:Estrogen Replacement Therapy; D005260:Female; D006801:Humans; D007107:Immune System / Q000187:drug effects; D007074:Immunoglobulin G / Q000097:blood*; D007075:Immunoglobulin M / Q000097:blood*; D017258:Medroxyprogesterone Acetate / Q000008:administration & dosage; D008875:Middle Aged; D012307:Risk Factors
chemical_list: D003176:Complement C3; D003181:Complement C4; D003271:Contraceptive Agents, Female; D007074:Immunoglobulin G; D007075:Immunoglobulin M; D004958:Estradiol; D017258:Medroxyprogesterone Acetate