Localization of interleukin-1 alpha, type 1 interleukin-1 receptor and interleukin-1 receptor antagonist in the synovial membrane and cartilage/pannus junction in rheumatoid arthritis.
Deleuran BW., Chu CQ., Field M., Brennan FM., Katsikis P., Feldmann M., Maini RN.
Using monoclonal antibodies and immunohistochemical techniques we have investigated the presence and distribution of interleukin-1 alpha (IL-1 alpha), type 1 IL-1 receptor (IL-1R1) and of interleukin-1 receptor antagonist (IL-1ra) in synovial tissue from 18 rheumatoid arthritis (RA) and eight osteoarthritis (OA) patients and in eight normal synovial tissue samples. IL-1 alpha and IL-1R1 were found in all of the samples examined. In RA, there were a large number of synovial cells expressing IL-1 alpha and IL-1R1, with 85 and 90% positive cells in the lining layer, 45 and 80% in the interaggregate area, and 90% of the vascular endothelial cells. In the lymphoid aggregates, 20% of the cells contained IL-1 alpha and 70% expressed IL-1R1. IL-1 alpha and IL-1R1 expressing cells showed a similar distribution in OA synovial membrane, but there was a smaller number of positive cells in the deeper area; and the staining intensity was lower. In contrast to IL-1 alpha and IL-1R1, IL-1ra was found only in 10/18 RA, 5/8 OA and 2/8 normal tissue samples. IL-1ra was detected in 35% of RA and 45% OA lining layer cells; 25% RA and 35% OA vascular endothelium; 10% RA and 15% OA interstitial cells and 30% cells in RA lymphoid aggregate. The staining intensity in both RA and OA tissues was comparably low. The presence of IL-1ra in RA and OA tissues was confirmed by Northern blot analysis for IL-1ra mRNA.(ABSTRACT TRUNCATED AT 250 WORDS)