lactoferrin and Lupus-Nephritis

The prevalence and clinical significance of antineutrophil cytoplasmic antibodies with specificity for lactoferrin was determined in patients with renal diseases. Antilactoferrin antibodies were found in only 12 of 920 patients (1.3%). These patients had either "pauci-immune" necrotizing crescentic glomerulonephritis (three cases) or lupus nephritis (nine cases). To verify whether antilactoferrin antibodies were specific for patients with systemic lupus erythematosus (SLE) and renal involvement, we studied 61 additional lupus patients, 40 with active lupus nephritis and 21 with active SLE and no renal involvement. Antilactoferrin antibodies were found in approximately 15% to 20% of patients with SLE, irrespective of the presence of renal involvement. We conclude that antineutrophil cytoplasmic antibodies with specificity for lactoferrin are only sporadically found in patients with renal diseases; these patients have either necrotizing crescentic glomerulonephritis or lupus nephritis. However, antilactoferrin antibodies are not a marker for renal involvement in SLE.

Topics: Adolescent; Adult; Aged; Antibodies, Antineutrophil Cytoplasmic; Antibody Specificity; Arthritis, Rheumatoid; Autoantibodies; Blotting, Western; Enzyme-Linked Immunosorbent Assay; Female; Fluorescent Antibody Technique; Humans; Lactoferrin; Lupus Erythematosus, Systemic; Lupus Nephritis; Male; Middle Aged; Neutrophils; Scleroderma, Systemic

Lactoferrin is a secondary granule protein of neutrophils. Seventy-nine systemic lupus erythematosus patients who fulfilled the ARA criteria for classification were tested for antibody against human lactoferrin (LF-ab) by ELISA. Thirty-one of these (39.2%) demonstrated elevated levels. There was significant correlation between LF-ab positivity and disease duration. Clinical flare was common with positive LF-ab (P less than 0.05). Disease manifestations were independent of antibody status except for an increased incidence of lymphadenopathy and crescentic gomerulonephritis among those who had LF-ab. No consistent immunofluorescence pattern could be demonstrated on alcohol-fixed neutrophils for the LF-ab positive sera. It is suggested that LF-ab is related to lupus activity, and can be useful as a marker for disease monitoring.

Topics: Adolescent; Adult; Antibodies, Antineutrophil Cytoplasmic; Autoantibodies; Biomarkers; Enzyme-Linked Immunosorbent Assay; Female; Fluorescent Antibody Technique; Humans; Lactoferrin; Lupus Erythematosus, Systemic; Lupus Nephritis; Lymphatic Diseases; Male; Middle Aged