Haemolytic complement level and ragocyte (R A cell) concentration in synovial fluid.

The presence of ragocytes (R A cells) (Delbarre, Kahan, Amor, and Krassinine, 1966; Hollander, McCarty, Astorga, and Castro-Murillo, 1965) and the relatively low levels of haemolytic complement (Hedberg, 1963, 1964; Pekin and Zvaifler, 1964; Peltier, Coste, and Delbarre, 1966) in synovial fluids from patients with rheumatoid arthritis which have been recently reported may be in some ways interrelated. It has been assumed that at least some of the inclusions in the ragocytes could contain complexes composed of rheumatoid factor and gammaglobulins (Delbarre and others, 1966; Hollander and others, 1965; Zucker-Franklin, 1966). Before being phagocytosed, these complexes would possibly fix complement, and at the same time the opsonizing properties of complement would enhance phagocytosis of these complexes by polymorphonuclear cells. Immunofluorescent detection of one of the C' components (C'3) in the ragocyte inclusions has not proved possible in our laboratory, but an inversely proportional relationship was noted between haemolytic complement levels and ragocytes expressed in terms of their concentration in synovial fluid. This correlation was statistically significant (P = 0 05).