BoneKEy Reports | BoneKEy Watch

Vγ9 Vδ2 T cells may be a biomarker for ONJ risk in patients on long-term BPs

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DOI:10.1038/bonekey.2013.61

Osteonecrosis of the jaw (ONJ) is a rare but severe adverse effect associated with long-term bisphosphonate (BP) use. In this study, a potential association between ONJ risk, BP use and Vγ9 Vδ2 T-cell activation was investigated.

Patients on long-term BP therapy, particularly if it was delivered intravenously, showed a significant loss of Vγ9 Vδ2 T cells while other T cells and monocytes and granulocytes remained stable. Six out of 68 patients were found to be diagnosed with ONJ and all had significantly lower levels of Vγ9 Vδ2 T cells compared to sex- and age-matched controls who had never taken BPs (P=0.001).

The authors suggest that the level of Vγ9 Vδ2 T cells may be a valuable biomarker to help predict which patients on long-term BP therapy may be at increased risk of developing ONJ.

Editor’s comment: This potential method of predicting ONJ risk in patients on BP therapy certainly merits further investigation. However, there is probably no causal link between the two, since therapy with denosumab, which does not affect the levels of Vγ9 Vδ2 T cells, also leads to some cases of ONJ. BPs and denosumab are both potent inhibitors of bone turnover, and this is more likely to explain the occurrence of ONJ after long-term drug therapy.

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