Detection of specific antibodies against human cultured chondrosarcoma (HCS-2/8) and osteosarcoma (Saos-2) cells in the serum of patients with osteoarthritis of the temporomandibular joint

To find specific humoral antibodies in sera from patients with temporomandi bular joint (TMJ) osteoarthritis (OA), an immortal human chondrocyte (HCS-2 /8) and osteoblast (Saos-2) cell line derived from a chondrosarcoma and an osteosarcoma, respectively, were used as source proteins of human antigens. Patients with chronically painful TMJ OA (n = 18) but no other joints symp toms were selected from a consecutive series of patients with temperomandib ular disorders and sex-matched asymptomatic controls (n = 8) were also recr uited. Cellular proteins of the HCS-2/8 and Saos-2 cells were subjected to Western blotting with the OA and control sera as probes. Band-recognition f requency and the peak optical density of the band were compared between gro ups by chi(2) and t-tests. OA sera recognized various bands for the chondro cytes, and one of these (47-kDa) was specific for the OA sera. In two OA pa tients whose treatment outcome was less favorable, the,reactivity against t he 47-kDa protein was relatively high. In addition, the OA sera clearly cro ss-reacted with recombinant HSP47. Based on these findings, an autoimmune r eaction against chondrocytes could be one of the exaggerating and/or perpet uating mechanisms in the pathophysiology of osteoarthritic TMJs, and the hu moral antibody titre against the HSP47-like protein derived from the chondr ocytes could be one of the possible markers for the prognosis of the joint pathology. (C) 1999 Elsevier Science Ltd. All rights reserved.