Multiple dysfunctions of polymorphonuclear leukocytes (PMNLs) contribute significantly to the increased morbidity and mortality among patients with end-stage renal disease. In the present study, we measured the PMNL content of beta(2)-microglobulin (beta(2)m) and lactoferrin in different states of renal insufficiency and after kidney transplantation. PMNLs were lysed ultrasonically and, after centrifugation, both proteins were assayed in the supernatant by enzyme-linked immunosorbent assay technique. Despite marked differences in plasma beta(2)m levels, no significant difference in PMNL content of beta(2)m and lactoferrin could be shown among the groups analyzed. There was also no correlation between plasma beta(2)m level and PMNL beta(2)m content. In control subjects, as well as in renal allograft recipients with a well-functioning graft, PMNL beta(2)m level correlated positively with PMNL lactoferrin level (pooled data, r = 0.55; P < 0.001; n = 55). Both proteins are considered to colocalize in peroxidase-negative PMNL granules. However, no correlation was found in the azotemic and uremic patient groups. Standard immunofluorescence staining of control PMNLs showed a cytoplasmic granular distribution of both granule proteins. However, in PMNLs of uremic patients, lactoferrin shifted to a perinuclear localization. PMNLs obtained from uremic individuals failed to elicit an increase in lactoferrin release after stimulation with the chemotactic peptide f-Met-Leu-Phe compared with PMNLs obtained from healthy volunteers. These data indicate abnormalities in uremic patients of PMNL granule lactoferrin content and release that are reversible after successful renal transplantation.