No abstract

The mechanisms which govern the production of autoantibodies and of tissue damage during systemic lupus (SLE) are still unclear. In the NZBxNZW F1 (BW) model of SLE glomerulonephritis, the activation and commitment of B cells are thought to play a major role in disease progression. Previous analysis has suggested that these mice have a substantial increase of marginal zone (MZ) B cells before the occurrence of the disease. Owing to the probable role of this B cell subset in autoantibody production, it was important to define the possible link between this abnormality and the occurrence of kidney damage. Using cytofluorometry analysis, we followed the splenic MZ B cell phenotype in different series of mice with shared autoimmune genetic background and histologically defined renal status. By comparing BW females and BW males, NZB and NZW mice, we confirm that BW mice have an increase in MZ B cells but this MZ B cells expansion is not directly linked to tissue lesions. Genetically modified BW female mice with a restricted repertoire of B and T cell antigen receptors, and which do not develop nephritis, exhibit the same increase of MZ B cells, suggesting that this increase does not depend on a specific set of antigens. Moreover, our analysis brings to light a pre-disease state in BW males, with autoantibody production and mesangial deposits.

By several analytic methods, the hyaluronate hexosamine concentration of synovial fluid was found low in the joint effusions of rheumatoid arthritis in comparison to normal synovial fluid. .4n increase in nonhyaluronate hexosamine was observed in rheumatoid synovial fluid of increased volume. Relative viscosity measurements after equilibrating hexosamine Concentration by dilution revealed few differences between rheumatoid and normal fluid.Plure methodos analytic monstrava basse concentrationes de hexosamina hyaluronate in le effusiones de liquido synovial de patientes con arthritis rheumatoide, comparate con normal liquido synovial. Esseva observate un augment0 de hexosamina non-hyaluronate in rheumatoide liquido synovial de volumine supranormal. Mesurationes de viscositate post equilibration del concentration de hexosamina per dilution non revelava multe differentias inter liquido rheumatoide e normal.HE CONCENTRATION of hyaluronate in synovial fluid from patients T with rheumatoid arthritis* and in normal synovial fluid has been determined by a number of workers. Using different methods, some workers have reported a similar concentration,lP2 and others a decreased c~n c e n t r a t i o n~~~ of hyaluronate in rheumatoid synovial fluid compared with normal fluid.In this repor:, the hyaluronate concentration of rheumatoid synovial fluid was determined by several methods described in a previous study of normal synovial fluid.6 Hyaluronate was precipitated in mucin clots from rheumatoid synovial fluid by adding acetic acid or a cobalt salt to the fluid, and was measured indirectly by determining hexosamine in these clots. A part of the total hexosamine of synovial fluid is not a component of hyaluronate, and it was shown in the method adopted that no hexosamine other than hyaluronate hexosamine was precipitated in mucin clots and that no hyaluronate hexosamine remained in the supernatant after a mucin clot was formed. Another method used to determine hyaluronate in rheumatoid synovial fluid was to measure the fall in hexosamine after digestion of the fluid with testicular hyaluronidase and dialysis of the digestion products.