title: Complement and antibody primary immunodeficiency in juvenile systemic lupus erythematosus patients.
abstract: OBJECTIVE
  To evaluate the frequency of primary immunodeficiencies (PID) in juvenile systemic lupus erythematosus (JSLE) patients.
  
  
  METHODS
  Some 72 JSLE patients were analyzed for levels of immunoglobulin classes and IgG subclasses and early components of the classical complement pathway. Determination of C4 gene copy number (GCN) and detection of type I C2 deficiency (D) were also performed.
  
  
  RESULTS
  PID was identified in 16 patients (22%): C2D in three, C4D in three, C1qD in two, IgG2D (<20 mg/dl) in four, IgAD (<7 mg/dl) in three, and IgMD (<35 mg/dl) in three; one of these patients presented IgA, C2 and C4D. Two patients had low C4 GCN and two had type I C2D. Demographic data, family history of autoimmune disease and PID, JSLE clinical findings, occurrence of infections, disease activity and therapies were similar in patients with and without PID (p > 0.05). Remarkably, the median of Systemic Lupus International Collaborating Clinics/ACR-damage index (SLICC/ACR-DI) was significantly higher in JSLE patients with PID compared with patients without these abnormalities (p = 0.0033), likewise the high frequency of SLICC/ACR-DI > 1 (p = 0.023).
  
  
  CONCLUSIONS
  A high frequency of PID was observed in JSLE patients, suggesting that these defects may contribute to lupus development. Our findings indicate that these two groups of PID should be investigated in severe pediatric lupus.
authors.affiliation: Children's Hospital, Faculdade de Medicina da Universidade de São Paulo, São Paulo, Brazil.
authors.forename: A A
authors.initials: AA
authors.lastname: Jesus
authors.forename: B L
authors.initials: BL
authors.lastname: Liphaus
authors.forename: C A
authors.initials: CA
authors.lastname: Silva
authors.forename: S Y
authors.initials: SY
authors.lastname: Bando
authors.forename: L E C
authors.initials: LE
authors.lastname: Andrade
authors.forename: A
authors.initials: A
authors.lastname: Coutinho
authors.forename: M
authors.initials: M
authors.lastname: Carneiro-Sampaio
mesh_terms: D000293:Adolescent; D000974:Antibodies, Antinuclear / Q000097:blood; D001323:Autoantibodies / Q000097:blood; D001483:Base Sequence; D002648:Child; D002675:Child, Preschool; D015922:Complement C1q / Q000037:antagonists & inhibitors / Q000172:deficiency / Q000276:immunology; D003175:Complement C2 / Q000172:deficiency / Q000235:genetics; D003181:Complement C4 / Q000172:deficiency / Q000235:genetics; D003165:Complement System Proteins / Q000172:deficiency* / Q000235:genetics; D017931:DNA Primers / Q000235:genetics; D005260:Female; D018628:Gene Dosage; D006801:Humans; D007136:Immunoglobulins / Q000097:blood / Q000145:classification; D007153:Immunologic Deficiency Syndromes / Q000150:complications* / Q000235:genetics / Q000276:immunology*; D007223:Infant; D008180:Lupus Erythematosus, Systemic / Q000150:complications* / Q000235:genetics / Q000276:immunology*; D008297:Male
chemical_list: D000974:Antibodies, Antinuclear; D001323:Autoantibodies; D003175:Complement C2; D003181:Complement C4; D017931:DNA Primers; D007136:Immunoglobulins; D015922:Complement C1q; D003165:Complement System Proteins