This study has investigated the chemotactic activity of polymorphonuclear cells (PMNs) isolated from the blood of patients with either articular rheumatoid arthritis (RA) or RA with extra-articular manifestations. A double fluorochrome immunofluorescent staining test has been employed to identify cell-associated immunoglobulins, probably immune complexes. The results suggest an inverse relationship between PMN chemotaxis and staining for cell-associated immunoglobulins, either surface bound or internalised. PMNs from RA patients showed reduced chemotaxis, and this was further reduced when RA PMNs were incubated for 30 minutes in autologous serum. A similar reduction in chemotaxis of normal PMNs occurred after incubation in RA sera. Preincubation of both RA and normal PMNs in RA serum (but not normal serum) resulted in an increase in the number of cells in which cell-associated immunoglobulins were demonstrable. This further reduction in RA PMN chemotaxis after exposure to autologous serum, together with an increase in immunoglobulin staining, may indicate selection of certain PMNs at the time of venepuncture due to cell margination. Such a selection process would call for a re-evaluation of previous studies of RA PMN function in relation to the disease process.