title: Detection of AA-type amyloid protein in labial salivary glands.
abstract: OBJECTIVE
  Among the diverse forms of amyloidosis, secondary type is the most frequent one. Diagnosis of amyloid deposition is based on the identification of the fibrillary protein amyloid by means of Congo Red (CR) or crystal violet (CV) stains, but these techniques do not differentiate between the different types of amyloid fibrils. The aim of this study was to identify by immunofluorescence (IF) AA amyloid a pathological fibrillar low-molecular-weight protein formed by cleavage of serum amyloid A (SAA) protein in labial salivary gland (LSG) biopsies from patients with secondary amyloidosis.
  
  
  METHODS
  98 LSG were studied, 65 were from patients with secondary amyloidosis and 33 from subjects with chronic inflammatory diseases without evidence of this anomaly. All sections were stained with hematoxylin and eosin (H &E), CV, CR and IF using anti-AA antibodies. Positive and negative controls were used for all techniques.
  
  
  RESULTS
  CV and CR demonstrated that the amyloid substance was found mainly distributed periductally (93.8%), followed by periacinar and perivascular locations (p <0.001); however, the IF demonstrated that amyloid AA substance predominates in the periacinar area (73.8%), followed by periductal and perivascular locations (p <0.001). IF has a sensitivity of 83%, 100% of specificity, 100% of predictive positive value and 75% of predictive negative value.
  
  
  CONCLUSIONS
  The results of this study confirm the efficacy of the LSG biopsy as a highly reliable method for diagnosis of secondary amyloidosis.
authors.affiliation: Departamento de Medicina Cirugía y Patología Oral, Facultad de Estomatología, Universidad Peruana Cayetano Heredia, Lima, Perú. sonia.sacsaquispe@upch.pe
authors.forename: Sonia-Julia
authors.initials: SJ
authors.lastname: Sacsaquispe
authors.forename: Eleazar-Antonio
authors.initials: EA
authors.lastname: Antúnez-de Mayolo
authors.forename: Rodolfo
authors.initials: R
authors.lastname: Vicetti
authors.forename: Wilson-Alejandro
authors.initials: WA
authors.lastname: Delgado
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000686:Amyloidosis / Q000378:metabolism / Q000473:pathology*; D005260:Female; D005455:Fluorescent Antibody Technique; D006801:Humans; D008046:Lip; D008297:Male; D008875:Middle Aged; D012466:Salivary Gland Diseases / Q000378:metabolism / Q000473:pathology*; D012470:Salivary Glands, Minor / Q000737:chemistry*; D012680:Sensitivity and Specificity; D000685:Serum Amyloid A Protein / Q000032:analysis* / Q000096:biosynthesis; D055815:Young Adult
chemical_list: D000685:Serum Amyloid A Protein