Antibody to streptococcal zymogen in the serum of patients with acute glomerulonephritis: A multicentric study

Gustavo Parra, Bernardo Rodríguez-Iturbe, Stephen Batsford, Arnold Vogt, Sergio Mezzano, Fernando Olavarría, Ramón Exeni, María Laso, Nelson Orta

Research output: Contribution to journalArticlepeer-review

56 Scopus citations

Abstract

Background. Cationic streptococcal proteinase (erythrotoxin B) and its precursor, zymogen, are putative nephritogenic antigens. The present study was designed to test whether serum titers to these antigens were good markers of streptococcal infection associated with glomerulonephritis. Methods. We studied 153 patients (male/female = 104/49, age range, 2 to 23 years old) with acute poststreptococcal glomerulonephritis (APSGN) from three countries (Venezuela, Chile and Argentina). The site of the initial infection was the skin in 84 patients, the throat in 55 patients and was unknown in 14 patients. In addition, we studied 23 patients (1 to 24 years old) with streptococcal infection not associated with glomerulonephritis (14 patients with impetigo and 9 patients with pharyngitis). As control group, 93 healthy individuals (54 males, 2 to 19 years old) were studied. Anti-zymogen and anti-proteinase titers were determined in a single laboratory by ELISA, and the intra- and interassay coefficients of variation were 5.3% and 8.5%, respectively. ASO titers and anti-DNAse B titers were also done. Results. Anti-zymogen titers of 1:800 to 1:3200 had likelihood ratios (sensitivity/1- specificity) for detection of streptococcal infection in APSGN patients ranging from 2.00 to 44.2 in Argentina, Chile and Venezuela. Anti-zymogen titers decreased one to two months after APSGN and they were 1 to 3 log2 dilutions higher that anti-proteinase titers. Receiver operating characteristic (ROC) curves showed that anti-zymogen titers were consistently superior to anti-streptolysin O and anti-DNAse B titers as markers for streptococcal infection in APSGN. Conclusions. These results suggest that increased anti-zymogen antibody titers are the best available marker for streptococcal infection associated with acute glomerulonephritis.

Original languageEnglish
Pages (from-to)509-517
Number of pages9
JournalKidney International
Volume54
Issue number2
DOIs
StatePublished - 1998

Keywords

  • Humoral immune response
  • Infection
  • Nephritogenic antigens
  • Poststreptococcal glomerulonephritis
  • Proteinase

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