title: Fibroblast-Like Synovial Cells in Rheumatoid Arthritis--the Impact of Infliximab on Hexosaminidase Activity.
abstract: BACKGROUND
  The effect of multiple infusions of infliximab (INF), a chimeric anti-tumor necrosis factor alpha antibody, on the concentration of hexosaminidase (HEX) activity in a synovial cell culture derived from human synovial inflamed fluid obtained from patients suffering from rheumatoid arthritis (RA) has been evaluated.
  
  
  OBJECTIVE
  The aim of this study was to prove INF efficacy in RA.
  
  
  METHODS
  Inflamed synovial fluid was taken from RA patients (a study group) and patients who had undergone knee trauma within 7 days (a control group). The following solutions of infliximab were used: 40, 60 and 140 µg/mL. Determination of the concentration of HEX activity in cell cultures was performed after 24, 48, 72 and 96 h of infliximab administration. To identify synoviocytes in cell culture immunohistochemical staining with vimentin and pancytokeratin was performed.
  
  
  RESULTS
  A predominance of fibroblast-like synovial cells has been observed in the study group. In the control group the concentration of HEX activity without adding infliximab to the cell culture was 283.00 nkat/mL. After 96 h of incubation with infliximab, the concentrations of HEX activity in cultured synoviocytes according to infliximab doses of 40, 60 and 140 µg/mL were respectively: 280.00, 271.50 and 293.50 nkat/mL. In the study group, the concentration of HEX activity without adding infliximab to the cell culture was 542.27 nkat/mL. The final concentrations of HEX activity of cultured fibroblast-like synovial cells measured after 96 h of incubation with infliximab were: 471.72, 498.27 and 556.72 nkat/mL, according to infliximab doses of 40, 60 and 140 µg/mL. In all groups (besides the infliximab concentration of 140 µg/mL after 96 h of incubation), the level of concentration of HEX activity was significantly higher in the study group compared to the control group, irrespective of infliximab concentration and time of infliximab incubation.
  
  
  CONCLUSIONS
  Infliximab changes the concentration of HEX activity depending on the drug dose and time of administration.
authors.affiliation: Department of Orthopedics and Traumatology, Bialystok Hospital, Poland.
authors.forename: Sławomir
authors.initials: S
authors.lastname: Olszewski
authors.affiliation: Department of Otolaryngology, Medical University of Bialystok, Poland.
authors.forename: Ewa
authors.initials: E
authors.lastname: Olszewska
authors.affiliation: Department of Pediatric Orthopedics, Medical University of Bialystok, Poland.
authors.forename: Janusz
authors.initials: J
authors.lastname: Popko
authors.affiliation: Department of Cytogenetics, Medical University of Bialystok, Poland.
authors.forename: Elżbieta
authors.initials: E
authors.lastname: Poskrobko
authors.affiliation: Department of Rheumatology and Internal Diseases, Medical University of Bialystok, Poland.
authors.forename: Stanisław
authors.initials: S
authors.lastname: Sierakowski
authors.affiliation: Medical College of the Universal Education Society, Łomża, Poland.
authors.forename: Krzysztof
authors.initials: K
authors.lastname: Zwierz
mesh_terms: D000328:Adult; D018501:Antirheumatic Agents / Q000494:pharmacology; D001172:Arthritis, Rheumatoid / Q000201:enzymology / Q000378:metabolism / Q000473:pathology; D002478:Cells, Cultured; D004305:Dose-Response Relationship, Drug; D057075:Enzyme Assays; D005260:Female; D005347:Fibroblasts / Q000187:drug effects* / Q000201:enzymology / Q000378:metabolism; D006596:Hexosaminidases / Q000378:metabolism*; D006801:Humans; D007150:Immunohistochemistry; D000069285:Infliximab / Q000494:pharmacology*; D007633:Keratins / Q000378:metabolism; D008297:Male; D008875:Middle Aged; D013582:Synovial Fluid / Q000166:cytology / Q000187:drug effects*; D013997:Time Factors; D014746:Vimentin / Q000378:metabolism
chemical_list: D018501:Antirheumatic Agents; D014746:Vimentin; D007633:Keratins; D000069285:Infliximab; D006596:Hexosaminidases