GRANULAR HISTIOCYTOSIS OF PELVIC LYMPH-NODES FOLLOWING TOTAL HIP-ARTHROPLASTY - THE PRESENCE OF WEAR DEBRIS, CYTOKINE PRODUCTION, AND IMMUNOLOGICALLY ACTIVATED MACROPHAGES

Infiltration of regional lymph nodes by macrophages has been demonstra ted after total joint arthroplasty. Although lymph nodes regulate the immune response, neither cytokine production nor the degree of immunol ogical activation of cells within these nodes after total joint arthro plasty has been investigated. Pelvic lymph nodes were obtained from fi ve patients who had had a total of eleven arthroplasties in seven hips three to twenty years before a pelvic staging procedure for adenocarc inoma (of the prostate in four patients and of the endometrium in one) . All lymph nodes had polyethylene or metal debris as well as effaceme nt of the normal nodal architecture by a histiocytic infiltrate. These changes were bilateral in the patients who had had an arthroplasty of both hips but were present only on the ipsilateral side in the patien ts who had had an arthroplasty of one hip. Analysis of specimens from pelvic lymph nodes on the side of the involved hip demonstrated intens e immunohistochemical staining of histiocytes for the major histocompa tibility complex class-II antigen HLA-DR, a marker of histiocyte immun e activation. In contrast, staining was absent in specimens from the c ontralateral lymph nodes as well as in those from seven patients who h ad had a prostatectomy but not a hip arthroplasty. Immunohistochemical staining for interleukin-1 beta, tumor necrosis factor-alpha, and int erleukin-6 demonstrated a much greater expression of these cytokines i n the involved lymph nodes. CLINICAL RELEVANCE: Additional improvement s in total joint replacement will be facilitated by a more thorough un derstanding of the biological response to the components and materials of implants. While local biological factors leading to failure of pro stheses are currently under intense investigation, the mechanisms and importance of regional and systemic immune responses to wear debris re quire further study.