Caparbo VF, et al. - Authors ascertained whether the osteoclastogenic capacity of peripheral blood mononuclear cells (PBMCs) is different in ankylosing spondylitis (AS) patients compared to controls. They also ascertained the relationship between osteoclastogenesis and clinical/laboratory parameters. A lower capacity to generate osteoclasts in vitro was demonstrated by the monocytes from male AS patients vs cells from controls. Findings suggested a negative association of osteoclastogenesis with disease duration. The idea that osteoclasts play a role in the physiopathology of bone disease in AS patients was supported in the findings.