title: Rate of Decline in Nontreponemal Antibody Titers and Seroreversion After Treatment of Early Syphilis.
abstract: Syphilis management is complex and demonstration of treatment response requires monitoring of nontreponemal antibody titers for a ≥ 4-fold decline and/or seroreversion to nonreactive titers.
  
  
  
  We evaluated data from a multicenter clinical trial of syphilis treatment conducted from 2000 to 2009 involving human immunodeficiency virus (HIV)-negative patients 18 years or older with early syphilis. To assess the rate of titer decline and seroreversion after effective therapy, rapid plasma reagin (RPR) titers were analyzed at 1, 3, 6, 9, and 12 months among patients with an appropriate treatment response. We plotted the rate of RPR titer decline after treatment, estimated the frequency of seroreversion, and conducted multivariate analyses to assess characteristics associated with seroreversion.
  
  
  
  Among 369 (79.4%) of 465 HIV-negative patients with early syphilis who had an appropriate treatment response, 333 participants had complete RPR data over 12 months. Although the decline in RPR titers was ≥ 4-fold among 88.0% (293/333) of participants at 3 months and ≥ 8-fold among 77.8% at 6 months, only 9.6% achieved complete RPR seroreversion at 6 months and 17.1% at 12 months after therapy. Male sex (adjusted odds ratio, 4.3; 95% confidence interval, 1.8-10.5) and baseline RPR titers ≤ 1:32 (adjusted odds ratio, 14.5; 95% confidence interval, 6.8-31.2) were associated with higher odds of seroreversion compared with females and titers > 1:32, respectively.
  
  
  
  Despite a ≥ 4-fold RPR titer decline after treatment, the majority of HIV-negative patients with early syphilis failed to have seroreversion at 12 months. Nontreponemal antibody titers often persist despite an appropriate treatment response.
authors.affiliation: From the *Division of Infectious Diseases, Department of Medicine, University of North Carolina at Chapel Hill, Chapel Hill, NC; †Emmes Corporation, Rockville, MD; ‡Department of Medicine, University of North Carolina at Madagascar, Antananarivo, Madagascar; §Division of Infectious Diseases, Department of Medicine, Louisiana State University Health Sciences, New Orleans, LA; ¶Division of Infectious Diseases, Department of Medicine, Indiana University, Indianapolis, IN; **FHI360, Durham, NC; and ††Division of Infectious Diseases, Department of Medicine, University of Alabama at Birmingham, Birmingham, AL.
authors.forename: Arlene C
authors.initials: AC
authors.lastname: Seña
authors.forename: Mark
authors.initials: M
authors.lastname: Wolff
authors.forename: Frieda
authors.initials: F
authors.lastname: Behets
authors.forename: David H
authors.initials: DH
authors.lastname: Martin
authors.forename: Peter
authors.initials: P
authors.lastname: Leone
authors.forename: Carol
authors.initials: C
authors.lastname: Langley
authors.forename: Linda
authors.initials: L
authors.lastname: McNeil
authors.forename: Edward W
authors.initials: EW
authors.lastname: Hook
mesh_terms: D000293:Adolescent; D000328:Adult; D000900:Anti-Bacterial Agents / Q000627:therapeutic use; D005260:Female; D018023:HIV Seronegativity / Q000276:immunology*; D006801:Humans; D008297:Male; D015999:Multivariate Analysis; D011935:Reagins / Q000097:blood*; D000069078:Seroconversion / Q000502:physiology*; D013587:Syphilis / Q000097:blood / Q000188:drug therapy* / Q000276:immunology / Q000382:microbiology; D013588:Syphilis Serodiagnosis / Q000379:methods*; D013997:Time Factors; D016896:Treatment Outcome; D014210:Treponema pallidum / Q000276:immunology*; D055815:Young Adult
chemical_list: D000900:Anti-Bacterial Agents; D011935:Reagins