Polymorphonuclear leukocyte (PMN) migration is measured in whole blood in a migration chamber consisting of a membrane filter (3-microns pores, 140 microns thick) with an integrated chemoattractant depot (FMLP in solid form) attached to a plastic container. Control chambers lack FMLP (blanks). One test unit requires 300 microliters blood. Numbers and distribution of the PMN immigrants into the filters are determined microscopically. Altogether 26 measurements of PMN migration in five juvenile rheumatoid arthritis (JRA) patients with varying disease activity were compared with the reactions of a healthy control group (N = 32). Correlations were calculated with conventional laboratory parameters (WBC, PLT, BSR, CRP, Hgb, serum Fe) and disease activity. In comparison with healthy controls, PMNs of JRA patients generally show a markedly increased penetration depth into the filters irrespective the presence of the chemoattractant or the disease activity. Increased migratory reactions to FMLP in comparison to blanks were found during high disease activity only. The PMN penetration depth correlates positively with the CRP, and reciprocally with the Hgb blood levels. The migration assay combines fast and simple processing with good preservation of the genuine PMN activation state.

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