title: Antibody-based diagnostic for 'refractory' periodontitis.
abstract: OBJECTIVE
  About 10-15% of US adults are 'refractory' to therapy for chronic periodontitis. Recently, studies suggest that these patients have elevated lysine decarboxylase activity in the sulcular microbiota. The aim of this study was to determine whether an elevated IgG antibody response to lysine decarboxylase, alone or with antibody to other bacterial antigens and baseline clinical measurements, would predict 'refractory' patients with high accuracy.
  
  
  METHODS
  Chronic periodontitis patients were treated using scaling and root planing (SRP) followed by maintenance SRP and 3-monthly re-examinations. If there was a loss of mean full mouth attachment or more than three sites appeared with > 2.5 mm new loss within a year, the subjects were re-treated (modified Widman flap surgery and systemically administered tetracycline). If attachment loss as above recurred, the subjects were 'refractory'. Baseline clinical measurements and specific antibody responses were used in a logistic regression model to predict 'refractory' subjects.
  
  
  RESULTS
  Antibody to a peptide portion of lysine decarboxylase (HKL-Ab) and baseline bleeding on probing (BOP) prevalence measurements predicted attachment loss 3 months after initial therapy [pIAL = loss (0) or gain (1)]. IgG antibody contents to a purified antigen from Actinomyces spp. (A-Ab) and streptococcal d-alanyl glycerol lipoteichoic acid (S-Ab) were related in 'refractory' patients (R2 = 0.37, p < 0.01). From the regression equation, the relationship between the antibodies was defined as linear (pLA/S-Ab = 0) or non-linear pLA/S-Ab = 1). Using pLA/S-Ab, pIAL and age, a logistic regression equation was derived from 48 of the patients. Of 59 subjects, 37 had 2-4 mm attachment loss and were assigned as 'refractory' or successfully treated with 86% accuracy.
  
  
  CONCLUSIONS
  HKL-Ab facilitated an accurate prediction of therapeutic outcome in subjects with moderate periodontitis.
authors.affiliation: Department. Biochemistry and Molecular Biology, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104, USA. Martin.levine@ouhsc.edu
authors.forename: M
authors.initials: M
authors.lastname: Levine
authors.forename: S
authors.initials: S
authors.lastname: LaPolla
authors.forename: W L
authors.initials: WL
authors.lastname: Owen
authors.forename: S S
authors.initials: SS
authors.lastname: Socransky
mesh_terms: D000190:Actinomyces / Q000276:immunology; D000328:Adult; D000595:Amino Acid Sequence; D000907:Antibodies, Bacterial / Q000032:analysis / Q000097:blood* / Q000737:chemistry; D000942:Antigens, Bacterial / Q000276:immunology; D001900:Boston; D002262:Carboxy-Lyases / Q000276:immunology; D016022:Case-Control Studies; D002908:Chronic Disease; D016124:Eikenella corrodens / Q000201:enzymology / Q000276:immunology; D005883:Gingival Crevicular Fluid / Q000201:enzymology / Q000276:immunology; D006801:Humans; D007074:Immunoglobulin G / Q000097:blood; D007159:Immunologic Tests; D016015:Logistic Models; D008875:Middle Aged; D009825:Oklahoma; D017622:Periodontal Attachment Loss / Q000473:pathology; D010518:Periodontitis / Q000175:diagnosis* / Q000276:immunology* / Q000382:microbiology; D011237:Predictive Value of Tests; D013291:Streptococcus / Q000276:immunology; D013682:Teichoic Acids / Q000276:immunology
chemical_list: D000907:Antibodies, Bacterial; D000942:Antigens, Bacterial; D007074:Immunoglobulin G; D013682:Teichoic Acids; C026244:alanyl-lipoteichoic acid; D002262:Carboxy-Lyases; C021520:lysine decarboxylase