Granulocyte and monocyte adsorptive apheresis (GMA) using a column filled with cellulose acetate (CA) beads (carriers) has been associated with a significant clinical efficacy in patients with rheumatoid arthritis and ulcerative colitis. To obtain further understanding on the mechanisms of disease modification by cellulose acetate-carrier-based GMA, in the present study, we investigated the mechanisms of granulocyte and monocyte adhesion to CA beads following exposure of human peripheral blood to the carriers at 37 degrees C for up to 60 min under controlled conditions. Cellulose acetate beads selectively adsorbed granulocytes, monocytes. CD19+ (B cells) and CD56+ (NK cells) lymphocyte subpopulations. The granulocyte and monocyte adsorption was inhibited by heat-inactivated plasma and EDTA, indicating that the adsorption was plasma protein (immunoglobulin, complement) and calcium dependent. Accordingly, granulocyte and monocyte adsorption was markedly enhanced by coating the carriers with IgG. Similarly, C3b was adsorbed onto the CA beads as a marker of complement activation. The results indicated that IgG and active complement fragments mediated leukocyte adhesion to CA beads via the FcgammaR and/or leukocyte complement receptor like CR3. Additionally, CA beads induced loss of expression of TNF receptors on CD16- granulocytes and CD14+ monocytes, but not on CD3+ lymphocytes In conclusion, CA beads might be an appropriate biomaterial for inducing extracorporeal immunomodulation as a treatment for auto-immune diseases which are associated with pathological leukocyte activity.

In the present study, we have shown that granulocyte and monocyte adsorption apheresis (GCAP), an extracorporeal apheresis instrument whose column contains cellulose acetate (CA) beads, is useful for skin diseases attributable to activated granulocytes and psoriatic arthritis (PsA). We assessed the clinical effectiveness of GCAP and investigated the mechanisms underlying the adsorption of pathogenic granulocytes. The effect of GCAP was assessed in 14 patients with neutrophilic dermatoses and 16 with PsA. The mechanisms by which the instrument adsorbs activated granulocytes were investigated using an in vitro mini-column system that mimics the GCAP. Skin lesions and arthropathy improved in 22 of 29 patients (75.9%) and 14 of 18 (77.8%), respectively. Mac-1 (CD11b/CD18) expression on the peripheral neutrophils, increased compared with normal subjects, was reduced by GCAP. In the mini-column system, CA beads adsorbed 50% neutrophils; and adsorption was inhibited significantly by treating plasma with EDTA and blood cells with antihuman CD11b monoclonal antibody. GCAP was useful for treating neutrophilic dermatoses and PsA. GCAP adsorbs Mac-1-expressing neutrophils to the CA beads by the binding of complement component (iC3b) on CA beads and CD11b expressed on activated neutrophils.

Plasma IgG, C3 derived complement activation fragments and leucocytes CD18 are involved in granulocyte adhesion to CA beads and hence the release of HGF and IL-1ra.

Apoptosis (programmed cell death) is a basic physiological process which determines specific patterns of tissue size and shape, and balance of cell number, during morphogenesis, and seems to play an integral role in oncogenic progression. Since dramatic changes of cellular glycosylation pattern are well known to be closely correlated with differentiation, development and oncogenesis, it is likely that similar specific changes are associated with apoptosis. However, this possibility has not been systematically investigated. We therefore carried out histological studies of many tumours and normal tissues for which a high incidence of apoptosis is believed to occur. Sections were stained with monoclonal antibodies (MoAbs) directed to carbohydrate antigens Le(y) and Le(x), proliferating cellular nuclear antigen (PCNA) and Fas (previously claimed to be an apoptosis-inducing antigen). Antibody staining patterns were compared with morphological cell characteristics as revealed by haematoxylin/eosin staining, and DNA fragmentation patterns (a marker of apoptosis) as revealed by 3'-OH nick-end labelling technique. We found that expression of Le(y) (defined by MoAb BM1) is closely correlated with the process of apoptosis, but not with cell proliferation or necrosis. Within Le(y)-positive areas of tissue sections, typical apoptotic morphological changes and DNA fragmentation (as revealed by positive nick-end labelling) were frequently observed in certain loci, although not all Le(y)-positive cells showed such signs of apoptosis. Le(y)-positive areas showed consistent negative staining by MoAb directed to PCNA and negative or weak staining by MoAb directed to Fas antigen, regardless of tissue source. No such trends were observed for Le(x) glycosylation. We conclude that Le(y) expression is a useful phenotypic marker predictive of apoptosis, i.e. some (although not all) Le(y)-positive cells subsequently become apoptotic.