T-lymphocytes are not necessary for particulate polyethylene-induced macrophage recruitment. Histologic studies of the rat tibia.

Immunological processes involving T-lymphocytes have been implicated in the mechanisms of aseptic loosening of joint endoprostheses. We report the histological reaction of bone to phagocytosable particles of high-density polyethylene (HDPE) in normal and T-cell deficient rats. A bolus of 3 x 10(7) polyethylene particles averaging 4.7 microns in size, mixed in 0.1 mL of sodium hyaluronate, was injected into the right proximal tibia of 10 normal and 10 T-cell deficient (nude) Rowett rats from the same litter. The left control side was injected with sodium hyaluronate alone. The animals were killed after 6 weeks. Transverse paraffin-embedded sections stained with hematoxylin and eosin were made of the implant area. On the control side, there was normal bone marrow without evidence of foreign body reaction. On the HDPE side, in both normal and T-cell deficient rats, macrophages were found to surround and engulf the particles, with no differences in the histological reactions. We conclude that T-lymphocytes are not necessary for the recruitment of macrophages to sites in which phagocytosable particles of HDPE have been implanted.