title: Diadenosine polyphosphates in tears of Sjogren syndrome patients.
abstract: OBJECTIVE
  To analyze the levels of diadenosine tetraphosphate (Ap(4)A) and diadenosine pentaphosphate (Ap(5)A) in tears of subjects with Sjögren syndrome and to compare them with those in a control group.
  
  
  METHODS
  Twelve subjects with a diagnosis of Sjögren syndrome and 20 healthy control subjects were invited to participate in the present study. Schirmer strips were used to measure tear secretion (Schirmer I test) and to collect tears. Ap(4)A and Ap(5)A were measured by high-pressure liquid chromatography (HPLC), and a dry eye questionnaire (DEQ) was used to evaluate dry eye symptomatology.
  
  
  RESULTS
  The mean concentrations of Ap(4)A and Ap(5)A in the Sjögren syndrome group were 2.54 ± 1.02 and 26.13 ± 6.95 μM, respectively. This group of patients was divided in two subgroups: four patients with normal tear production and eight patients with low tear production. Concentrations of Ap(4)A, and Ap(5)A in patients with normal tear production (Schirmer test result, 12.3 ± 1.2 mm) were 0.47 ± 0.20 and 8.03 ± 3.27 μM, respectively. In the patients with low tear production (Schirmer test result, 1.0 ± 0.3 mm), the concentrations were 4.09 ± 1.36 and 39.51 ± 8.46 μM, respectively and in the control group, 0.13 ± 0.03 and 0.04 ± 0.02 μM, respectively.
  
  
  CONCLUSIONS
  Patients with Sjögren syndrome have abnormally elevated concentrations of diadenosine polyphosphates, indicating that these compounds could be used in the diagnosis of this disease.
authors.affiliation: Departamento de Óptica II, Optometría y Visión, Escuela Universitaria de Óptica, Universidad Complutense de Madrid, Madrid, Spain. jgcarrac@opt.ucm.es
authors.forename: Gonzalo
authors.initials: G
authors.lastname: Carracedo
authors.forename: Assumpta
authors.initials: A
authors.lastname: Peral
authors.forename: Jesús
authors.initials: J
authors.lastname: Pintor
mesh_terms: D000328:Adult; D000368:Aged; D002851:Chromatography, High Pressure Liquid; D015226:Dinucleoside Phosphates / Q000378:metabolism*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D012859:Sjogren's Syndrome / Q000175:diagnosis / Q000378:metabolism*; D011795:Surveys and Questionnaires; D013666:Tears / Q000378:metabolism*
chemical_list: D015226:Dinucleoside Phosphates; C012275:P(1),P(5)-di(adenosine-5'-)pentaphosphate; C020733:diadenosine tetraphosphate