Cervical discs are most susceptible to beta 2-microglobulin amyloid deposition in the vertebral column

Intervertebral discs of 41 chronic renal failure autopsy cases were examined histologically and immunohistochemically to assess the distribution of beta 2-microglobulin-associated (beta 2m) amyloid in the vertebral column. The results demonstrated beta 2m amyloid to appear first in the cervical discs, then in the lumbar and upper thoracic discs, and finally in the middle and lower thoracic discs as the dialysis period is prolonged. The shortest dialysis period for which beta 2m amyloid was detected was one year and seven months. Deposition of beta 2m amyloid was most remarkable in the C4-5, 5-6, and 6-7 levels, which are known to sustain severe mechanical stress in daily life. Thus it is suggested that local mechanical stress accelerates beta 2m amyloidosis. A marked macrophage reaction was observed around the amyloid in cases of severe amyloidosis, the macrophages themselves being immunohistochemically positive for IL-1 beta and TNF-alpha. Amyloid deposition and reactive inflammation mediated by cytokines appear to be closely related to the pathogenesis of destructive spondyloarthropathy.