Erythrocyte aggregation in rheumatoid arthritis: Cell and plasma factor's role.
Increase in erythrocyte aggregation (EA) is pathognomonic for rheumatoid arthritis (RA), and its estimation through erythrocyte sedimentation rate (ESR) is part of DAS 28-4 activity diagnosis, with low correlation with EA and that does not discriminate the contribution of cell factors that increase aggregation.


OBJECTIVE
To analyse cell and plasma factors that might be involved in EA increase, to understand how RA affects blood components, thus modifying blood fluid behavior.


METHODS
One hundred women presenting active RA were compared with age-matched controls (C). EA was measured by transmitted light, obtaining two parameters: 2k2n0, characterizing the aggregation process kinetics and s0/n0, estimating aggregates size. Cell factors assays: erythrocyte deformability, by filtration through nucleopore membranes, cell shape, by microscopy, and membrane fluidity by EPR. Plasma: total proteins and CRP, albumin, fibrinogen (Fb), by gravimetry, and IgG and IgM by single radial immuno-diffusion.


RESULTS
AR and C (x+/-SE). 2k2n0: 31.83+/-2.84, 23.75+/-1.91; s0/n0: 0.92+/-0.05, 0.87+/-0.04. Rigidity index (RI): 14.79+/-4.71, 6.92+/-1.31. Morphological index: 0.28+/-0.03, 0.30+/-0.05, n.s. Fb (mg/dl): 382+/-80, 299+/-70. IgG (mg/dl): 1580+/-219, 1296+/-158; IgM (mg/dl) 233+/-28, 183+/-23; albumin (g/dl) 3.84+/-0.44, 3.77+/-0.51 n.s. p<0.05 accepted. Correlations: 2k2n0 vs. Fb r=0.66; s0/n0 vs. Fb r=0.51; 2k2n0 vs. Igs r=0.65; s0/n0 vs. Igs r=0.56. 2k2n0 vs. RI r=-0.59; s0/n0 vs. RI=-0.52, p<0.05.


CONCLUSIONS
Plasma factors, Igs and Fb increased aggregation, since RI is altered, this reduces the process efficiency regarding aggregation. Patients with active RA present an increased EA, with values modifications associated with the activity index DAS 28-4, thus becoming an RA activity indicator.
Luquita
A
A
Cátedra de Física Biológica, Facultad de Ciencias Médicas, Universidad Nacional de Rosario, Santa Fe 3100, 2000 Rosario, Argentina. luquitale@hotmail.com
Urli
L
L
Svetaz
M J
MJ
Gennaro
A M
AM
Volpintesta
R
R
Palatnik
S
S
Rasia
M
M
D000328:Adult; D000368:Aged; D001172:Arthritis, Rheumatoid / Q000097:blood*; D015415:Biomarkers / Q000097:blood; D016022:Case-Control Studies; D004903:Erythrocyte Aggregation; D004907:Erythrocyte Deformability; D005260:Female; D005340:Fibrinogen / Q000032:analysis; D006801:Humans; D007136:Immunoglobulins / Q000097:blood; D008875:Middle Aged; D012217:Rheumatoid Factor / Q000097:blood; D012720:Severity of Illness Index
D015415:Biomarkers; D007136:Immunoglobulins; D005340:Fibrinogen; D012217:Rheumatoid Factor