USE OF IMMUNOHISTOLOGIC AND IN-SITU HYBRIDIZATION TECHNIQUES IN THE EXAMINATION OF SACROILIAC JOINT BIOPSY SPECIMENS FROM PATIENTS WITH ANKYLOSING-SPONDYLITIS

Objective, To investigate mechanisms involved in inflammation and new bone formation in the sacroiliac (SI) joints of patients with ankylosi ng spondylitis (AS), Patients and methods, Computed tomography-assiste d biopsy of the SI joint was performed in 5 patients with AS with a me an disease duration of 4.5 years and radiographic stage 2-3 disease, I mmunohistologic studies were performed with the alkaline phosphatase-a nti-alkaline phosphatase technique, and cytokine messenger RNA (mRNA) was detected by in situ hybridization. Results, Dense cellular infiltr ates with varying amounts of CD3+ cells (mean +/- SD 53.3 +/- 24.1%), CD4+ cells (29.7 +/- 17.6%), CD8+ cells (15.8 +/- 11.4%), CD14+ cells (23.6 +/- 16.9%), CD45RO+ cells (48.4 +/- 23.6%), and CD45RA+ cells (4 .5 +/- 2.9%) were found in the synovial portion of the SI joints of al l 5 patients, In these infiltrates a high amount of tumor necrosis fac tor alpha (TNF alpha) mRNA and, near the site of new bone formation, a lower amount of transforming. growth factor beta (TGF alpha) mRNA, we re detected, while no message for interleukin-l was found in the 3 pat ients examined by this technique,Conclusion. The presence of T cells a nd macrophages was demonstrated in cellular infiltrates in the SI join ts of 5 patients with active AS, The finding of abundant TNF alpha mes sage in these joints could have implications regarding potential immun otherapeutic approaches to this disease. TGF beta might be involved in new bone formation in AS.