lactoferrin and Glomerulonephritis

To investigate the prevalence and clinical relevance of immunoglobulin (Ig) isotypes of antimyeloperoxidase (MPO) and antilactoferrin (LF) antibodies in collagen diseases, enzyme-linked immunosorbent assay was employed to detect the Ig isotypes of both antibodies. The purified proteins of MPO and LF were used as two major representative antigens for anti-neutrophil cytoplasmic antibodies (ANCA) with a perinuclear staining pattern by an indirect immunofluorescent technique. We examined 131 serum samples from 79 patients with rheumatoid arthritis (RA), 32 with systemic lupus erythematosus (SLE), 14 with progressive systemic sclerosis (PSS), 6 with polymyositis/dermatomyositis (PM/DM), and 5 with idiopathic crescentic glomerulonephritis who served as positive controls and 36 healthy subjects who served as controls. A limited number of patients with RA (4-10%), SLE (6-9%), and PSS (7-14%) but not PM/DM showed positive IgG or IgA anti-MPO antibody (MPO-ANCA) but not IgM MPO-ANCA. However, 10-20% of RA, 40-60% of SLE, 20-36% of PSS but none of the PM/DM patients showed positive IgG, IgA, or IgM anti-LF antibody (LF-ANCA). MPO- and LF-ANCA positivity in RA patients was correlated with markers of disease activity such as the erythrocyte sedimentation rate, C-reactive protein, and serum Ig levels. IgG LF-ANCA but not MPO-ANCA positivity in SLE patients also was correlated with the disease activity index but not with clinical features. Neither MPO- nor LF-ANCA positivity in PSS patients was correlated with any clinical features. Overall, both MPO- and LF-ANCA were found mainly in RA, SLE, and PSS patients but not in PM/DM patients. The Ig isotypes of MPO- and LF-ANCA frequently belonged to both IgG and IgA and rarely to the IgM class. Both MPO- and LF-ANCA positivity reflected disease activity in RA and SLE rather than specific organ involvement.

Topics: Adult; Aged; Aged, 80 and over; Antibodies, Antineutrophil Cytoplasmic; Antibody Specificity; Arthritis, Rheumatoid; Autoantigens; Autoimmune Diseases; Collagen Diseases; Dermatomyositis; Enzyme-Linked Immunosorbent Assay; Female; Glomerulonephritis; Humans; Immunoglobulin A; Immunoglobulin G; Immunoglobulin Isotypes; Immunoglobulin M; Lactoferrin; Lupus Erythematosus, Systemic; Male; Middle Aged; Organ Specificity; Peroxidase; Polymyositis; Scleroderma, Systemic

Using immunofluorescence, it has been shown that leukocyte thermostable alpha-glycoprotein (LTAG) and leukocyte beta-globulin (LBG) are, like lactoferrin, components of polynuclear leukocytes. These proteins were found in the perinuclear zone, cytoplasm membrane and extracellularly. Serum LTAG concentration increases in immune inflammatory diseases. In severe forms of diabetes and glomerulonephritis there is a rise in LBG concentration. The biological role of LTAG and LBG is unknown.

Topics: Beta-Globulins; Blood Proteins; C-Reactive Protein; Diabetes Mellitus; Fluorescent Antibody Technique; Glomerulonephritis; Glycoproteins; Granulocytes; Humans; Lactoferrin; Neutrophils

An immunopathological analysis of renal tissue from 105 patients was undertaken: (1) to clarify the relationship of the secretory immune system to renal diseases in which glomerular deposits of immunoglobulin A, (alpha chain), occurred; (2) to determine the lower nephron localization of secretory component and alpha chain in renal disease. This study, which included twenty-four patients with glomerular deposits of alpha chain, failed to reveal glomerular localization of secretory IgA. Secretory component was not found in renal tubular cells in kidneys with normal or minimally abnormal renal histology. In contradistinction to these findings, significant amounts of secretory component were found in tubular epithelial cells and casts in tissue from fifty-one patients with morphological evidence of significant renal damage; this localization had no correlation with glomerular deposits of IgA, IgM or other immunoreactants. Alpha Chain was rarely found in the tubular epithelium or in interstitial round cells; fifteen patients had alpha chain in casts. We conclude that the glomerular localization of immunoglobulin in glomerulonephritis is not derived from the secretory immune system, and the IgA present in glomeruli is not secretory IgA. The finding of secretory component in tubular cells in diseased kidneys without alpha chain may support an hypothesis for an independent role for secretory component in renal disease, apart from its function in the transport and stabilization of secretory IgA.

Topics: Adolescent; Adult; Child; Child, Preschool; Glomerulonephritis; Graft Rejection; Humans; Immunity; Immunoglobulin A; Immunoglobulin A, Secretory; Immunoglobulin alpha-Chains; Immunoglobulin mu-Chains; Kidney Glomerulus; Lactoferrin; Middle Aged; Secretory Component