title: Association between apoptotis and CD4(+)/CD8(+) T-lymphocyte ratio in aseptic loosening after total hip replacement.
abstract: Particle-induced osteolysis is a major cause of aseptic loosening after total joint replacement. While the osteolytic cascade initiated by cytokine release from macrophages has been studied extensively, the involvement of T-lymphocytes in this context is controversial and has been addressed by only a few authors. In a former study we detected that the quantity of T-lymphocytes may be influenced by apoptosis in patients with aseptic loosening. In this study we intended to find out more details about the apoptosis-induced shifting of the T-cell number. We focused our interest on the CD4(+) and CD8(+) T-cells and their relative ratio. Caspase-3 cleaved was evaluated immunohistochemically to detect apoptotic T-cells in capsules and interface membranes from patients with aseptic hip implant loosening and a varying degree of caspase-3 cleaved expression in CD4(+) and CD8(+) T-lymphocytes was detected. Moreover, a relationship between the intensity of the apoptotic reactions and the radiological extent of osteolysis was observed. The number of CD4(+) cells was decreased in the presence of strong apoptotic reactions, respectively extensive osteolysis, while CD8(+) cells were affected to a much lower degree. Thus, the CD4(+)/CD8(+) ratio changed from 1.0 in cases with only small areas of periprosthetic osteolysis and minimally intense apoptosis to 0.33 in cases with large areas of osteolysis. This may suggest a causal relationship between the apoptosis-induced shift in the CD4(+)/CD8(+) ratio and the osteolysis respectively aseptic loosening. It is possible that these findings may lead to a new understanding of particle-induced osteolysis.
authors.affiliation: Department of Orthopaedics, University of Duisburg-Essen, Essen, Germany. stlandy@t-online.de
authors.forename: Stefan
authors.initials: S
authors.lastname: Landgraeber
authors.forename: Marius
authors.initials: M
authors.lastname: von Knoch
authors.forename: Franz
authors.initials: F
authors.lastname: Löer
authors.forename: Jochen
authors.initials: J
authors.lastname: Brankamp
authors.forename: Michael
authors.initials: M
authors.lastname: Tsokos
authors.forename: Florian
authors.initials: F
authors.lastname: Grabellus
authors.forename: Kurt Werner
authors.initials: KW
authors.lastname: Schmid
authors.forename: Martin
authors.initials: M
authors.lastname: Totsch
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D017209:Apoptosis; D019644:Arthroplasty, Replacement, Hip / Q000009:adverse effects*; D015496:CD4-Positive T-Lymphocytes / Q000378:metabolism*; D018414:CD8-Positive T-Lymphocytes / Q000378:metabolism*; D053148:Caspase 3 / Q000378:metabolism; D005260:Female; D006622:Hip Prosthesis / Q000009:adverse effects*; D006801:Humans; D007150:Immunohistochemistry; D008297:Male; D008875:Middle Aged; D010014:Osteolysis / Q000209:etiology
chemical_list: D053148:Caspase 3