Production of IL-6 by T cells from the femoral head of patients with rapidly destructive coxopathy (RDC)

Abstract

SUMMARYRDC is a syndrome with unknown etiology that causes rapid destruction of a hip joint. We have investigated the production of osteoclast-activating cytokines (IL-6, IL-la and tumour necrosis factor-alpha (TNF-a)), interferon-gamma (IFN-y) and IL-8 by T cells in the affected joint. The level of IL-6 produced by the T cell lines (TCL) established from the femoral head was significantly higher than that from patients' or healthy donors' peripheral blood mononuclear cells (PBMC). IL-6 production by the TCL from synovial membrane or from patients' PBMC was also significantly higher than that from healthy donors' PBMC. IL-la production by the TCL from the femoral head was significantly higher than any of the other groups when all the TCL were used for the analysis. TNF-a production was highest in the TCL from patients' PBMC. The levels of IFN-y or IL-8 were not significantly different among these four groups. The plasma levels of all these cytokines except for IFN-y, that was rather lower, in RDC patients were not significantly different from those in osteoarthrosis or trauma patients, or healthy donors. These results suggest that T cells at the affected femoral head, and also synovial membrane to some extent, are involved in bone resorption through the production of IL-6 and probably IL-la in patients with RDC.

Rapidly destructive osteoarthritis of the hip joint: a case series

“…Pathologically, many investigators have reported that osteoclast count is significantly greater in active areas of the hip in RDHD than in osteoarthritic patients along with vascular-rich granulation, suggest ing that vascularity is an important factor in the osteolysis and destruction of the bone [ 14 , 15 ]. Others have demonstrated elevated levels of interleukin-6 (IL-6), IL-1β in the joint fluid of affected patients as well as increased secretion of matrix metalloproteinases(MMP) by fibroblasts from the affected synovium and subchondral cysts [ 16 , 17 ]. Although implicated as a causative factor, no genetic analysis such as that using human leukocyte antigen for rapidly destructive arthropathy has been reported.…”

Osteoclast‐related markers in the hip joint fluid with subchondral insufficiency fracture of the femoral head

“…Among several kinds of multinuclear giant cells, osteoclast cells can be characteristically identified as the multinuclear cells within the indentations of the bone matrix . Histopathologically, HE staining has also reportedly revealed the presence of many osteoclast‐like multinuclear giant cells at the center of the bone destruction in RDA . In reference to these reports, the number of multinuclear giant cells along the trabecular bone at the subchondral bone region per mm 2 was calculated using a mid‐coronal slice of all histopathological specimens (Fig.…”

Synovial joint fluid cytokine levels in hip disease

“…Mature and activated osteoclasts occur in the synovial membrane and granulomatous bone marrow lesions occur in the focal destructive portion of the femoral heads [11]. Femoral head bone resorption is brought about through the production of IL-6 in RDC hips [12]. Osteoclast cells also occur at the reparative zone of the collapsed femoral head in hips with osteonecrosis (ON) of the femoral head [13].…”