Double immunofluorescence studies of immunoglobulins, complement components and their control proteins in patients with IgA nephropathy

A study on double immunofluorescent staining of immunoglobulins, complement components, and their control proteins in renal tissues from patients with IgA nephropathy is described. Renal biopsy specimens were obtained from patients with IgA nephropathy. These biopsy specimens were stained with anti sera to human C1q, C4-binding protein, and beta 1H globulin by indirect immunofluorescent staining. These samples were then stained with rhodamine-conjugated anti human IgG, IgM, and IgA. Although C1q and C4-binding protein do not combine with IgA, they ubiquitously combine with IgG and/or IgM. beta 1H globulin also combine with IgG, IgM and/or IgA. It was demonstrated that the complement system activated in IgA nephropathy was via both alternative and classical pathways. The presence of C4-binding protein in glomeruli appeared to be a more sensitive indicator of classical pathway activation than the presence of C4.     

EVALUATION OF THE STAINING CONDITIONS OF IMMUNOFLUORESCENCE IN PRIMARY GLOMERULONEPHRITIS

A study of the evaluation of various staining conditions of immunofluo-rescence in renal biopsy specimens is described. Renal biopsy specimens were obtained from 52 patients with various types of primary glomerulone-phritis, and stained with fluorescein-conjugated anti-human IgG, IgA, or IgM antisera under various staining conditions. The results indicated that IgM was more prominently stained at 4°C overnight than at 37°C or room temperature by the immunofluorescent staining. Both IgG and IgA did not show any dmerences in the pattern of staining under different conditions. It is suggested that the different staining conditions of immunofluorescence in patients with glomerulonephritis is useful for the evaluation of the classes of immunoglobulins deposited in the glomeruli.     

EVALUATION OF THE STAINING FINDINGS OF IMMUNOFLUORESCENCE IN UNFIXED OR FIXED RENAL BIOPSY SPECIMENS FROM PATIENTS WITH IGA NEPHROPATHY and MEMBRANOUS NEPHROPATHY

A study on the evaluation of staining findings of immunofluorescence in unfixed or fixed renal biopsy specimens is described. Renal biopsy specimens obtained from ten patients with IgA nephropathy and membranous nephropathy were embedded in gelatin or paraffin matrix. Renal biopsy specimens embedded in paraffin matrix were digested with 0.05% protease. The specimens were stained with FITC-conjugated anti-human IgA, IgG, IgM or C3 antisera at 4°C overnight. IgA, IgG or IgM were markedly observed in glomeruli using unfixed materials embedded in gelatin matrix or 10% neutral buffered formalin fixed materials embedded in paraffin matrix from patients with IgA nephropathy and membranous nephropathy. There was no significant difference in the intensity or distribution of IgA, IgG or IgM deposition among the two different conditions of immunofluorescence in patients with such diseases. Although the deposition of IgA using unfixed materials embedded in gelatin matrix was prominently coarse granular or lumpy in glomeruli from patients with IgA nephropathy, that of IgA using 10% formalin fixed materials embedded in paraffin matrix was fine granular and/or interrupted linear in glomeruli. It was suggested that the immunofluorescence in renal biopsy specimens embedded in paraffin matrix after digestion with protease is useful for the evaluation of immunoglobulins in glomeruli from patients with IgA nephropathy or membranous nephropathy. ACTA PATHOL. JPN. 35 : 315–321, 1985.     

Evaluation of the staining findings of immunofluorescence in unfixed or fixed renal biopsy specimens from patients with IgA nephropathy and membranous nephropathy

A study on the evaluation of staining findings of immunofluorescence in unfixed or fixed renal biopsy specimens is described. Renal biopsy specimens obtained from ten patients with IgA nephropathy and membranous nephropathy were embedded in gelatin or paraffin matrix. Renal biopsy specimens embedded in paraffin matrix were digested with 0.05% protease. The specimens were stained with FITC-conjugated anti-human IgA, IgG, IgM or C3 antisera at 4 degrees C overnight. IgA, IgG or IgM were markedly observed in glomeruli using unfixed materials embedded in gelatin matrix or 10% neutral buffered formalin fixed materials embedded in paraffin matrix from patients with IgA nephropathy and membranous nephropathy. There was no significant difference in the intensity or distribution of IgA, IgG or IgM deposition among the two different conditions of immunofluorescence in patients with such diseases. Although the deposition of IgA using unfixed materials embedded in gelatin matrix was prominently coarse granular or lumpy in glomeruli from patients with IgA nephropathy, that of IgA using 10% formalin fixed materials embedded in paraffin matrix was fine granular and/or interrupted linear in glomeruli. It was suggested that the immunofluorescence in renal biopsy specimens embedded in paraffin matrix after digestion with protease is useful for the evaluation of immunoglobulins in glomeruli from patients with IgA nephropathy or membranous nephropathy.     

DEPOSITION OF IGA-DOMINANT IMMUNE-COMPLEXES IN MUSCULAR VESSELS FROM PATIENTS WITH IGA NEPHROPATHY

The emergence of immunoglobulin depositions in muscular vessels from patients with IgA nephropathy was examined to determine whether the pathogenesis of IgA nephropathy was mediated by circulating IgA-dominant immune-complexes. Muscle biopsy specimens were obtained from the right flank at the same time of modified open renal biopsy. These biopsy samples were stained with fluorescein-conjugated anti human IgG, IgA, IgM, IgE, and C3 antisera It was demonstrated that the depositions of IgA and/or C3 were observed in muscular vessels from some patients with IgA nephropathy. It is indicated that IgA nephropathy might be mediated by circulating IgA-dominant immune-complexes.     

IMMUNOFLUORESCENCE STAINING IN UNFIXED OR FIXED RENAL BIOPSY SPECIMENS FROM PATIENTS WITH DIABETIC NEPHROPATHY

Immunofluorescence staining in unfixed or fixed renal biopsy specimens were evaluated in nine patients with diabetic nephropathy in order to elucidate if immunofluorescence staining is applicable in fixed renal tissues in such patients. Renal biopsy specimens were embedded in gelatin or paraffin matrix. Renal biopsy specimens embedded in paraffin matrix were digested with 0.05% protease. Immunofluorescent studies of kidney tissues were performed by staining with FITC-labeled heavy chain specific anti-human IgG, IgA, IgM, acute phase reactant (APR) proteins such as α-1-anti-trypsin (αl-AT), haptoglobin (Hpt) and β-lipoprotein (β -Lp) antisera, and then examined with a fluorescent microscope. Linear and nodular deposition of IgG, IgA, IgM, α 1-AT, Hpt, and β -Lp were observed in the glomerular capillary walls of the renal specimens embedded in paraffin matrix. The staining patterns in specimens embedded in paraffin matrix was similar to that embedded in gelatin matrix. There was no significant difference in the intensity or distribution of IgG, IgM, αl-AT, and β-Lp deposition among the two different conditions of immunofluorescence in patients with diabetic nephropathy. It was suggested that immunofluorescence staining in renal biopsy specimens embedded in paraffin matrix after digestion with protease is useful for the evaluation of IgG, IgM, APR proteins, and β -Lp in glomeruli from patiens with diabetic nephropathy.     

Immunopathology of bullous pemphigoid. Basement membrane deposition of IgE, alternate pathway components and fibrin

Sixteen patients with bullous pemphigoid were examined using direct and indirect immunofluorescent techniques with antisera specific for C1q, C4, C3, C5, C3 proactivator, properdin, fibrinogen, IgA, IgM, IgG and IgE. The results of these studies are consistent with the activation of complement via the classical (antibody–C1q) sequence as well as via the alternate pathway. Fibrinogen and/or fibrin derivatives were demonstrated on the basement membrane of ten of fifteen patients tested and IgE basement membrane staining was found in four individuals.     

Immunohistochemical study of the membrane attack complex of complement in IgA nephropathy

Summary The localization of the membrane attack complex of complement (MAC) was examined in the normal human kidneys and in biopsy specimens from patients with primary IgA nephropathy by immunofluorescent and immunoelectron microscopies. Immunofluorescent staining for MAC was significantly more intense than in the normal kidneys, and was observed in the mesangium and occasionally along the glomerular capillary walls of 22 of 30 patients with IgA nephropathy. By dualstaining, the MAC deposits were generally concordant with the deposits of IgA, C3, C5 and C9, or of IgG, when present. C1_q or C4 was infrequently observed in the glomeruli. Immunoelectron microscopy revealed various staining patterns of glomerular MAC deposition; homogeneous fine-granular staining beneath the glomerular basement membrane (GBM) in the paramesangial zone, patchy staining within the mesangial electron dense deposits (EDD), and ring-shaped or ribbon-like staining, associated with the striated membrane structures (SMS), in the matrix of the mesangium, GBM and tubular basement membrane (TBM). This study suggests that the terminal complement system is activated, mainly by an alternative complement pathway mechanism, in the mesangium of IgA nephropathy, and is associated with the paramesangial lesion and EDD. MAC deposition in glomerular SMS may also result from in situ activation rather than trapping from the circulation. There was little correlation between glomerular MAC deposition and proteinuria or renal histology of patients with IgA nephropathy.     

Immunofluorescence staining in unfixed or fixed renal biopsy specimens from patients with diabetic nephropathy

Immunofluorescence staining in unfixed or fixed renal biopsy specimens were evaluated in nine patients with diabetic nephropathy in order to elucidate if immunofluorescence staining is applicable in fixed renal tissues in such patients. Renal biopsy specimens were embedded in gelatin or paraffin matrix. Renal biopsy specimens embedded in paraffin matrix were digested with 0.05% protease. Immunofluorescent studies of kidney tissues were performed by staining with FITC-labeled heavy chain specific anti-human IgG, IgA, IgM, acute phase reactant (APR) proteins such as alpha 1-anti-trypsin (alpha 1-AT), haptoglobin (Hpt) and beta-lipoprotein (beta-Lp) antisera, and then examined with a fluorescent microscope. Linear and nodular deposition of IgG, IgA, IgM, alpha 1-AT, Hpt, and beta-Lp were observed in the glomerular capillary walls of the renal specimens embedded in paraffin matrix. The staining patterns in specimens embedded in paraffin matrix was similar to that embedded in gelatin matrix. There was no significant difference in the intensity or distribution of IgG, IgM, alpha 1-AT, and beta-Lp deposition among the two different conditions of immunofluorescence in patients with diabetic nephropathy. It was suggested that immunofluorescence staining in renal biopsy specimens embedded in paraffin matrix after digestion with protease is useful for the evaluation of IgG, IgM, APR proteins, and beta-Lp in glomeruli from patients with diabetic nephropathy.     

DETECTION OF IMMUNOGLOBULINS AND OTHER SERUM PROTEINS IN THE DERMAL AND GLOMERULAR CAPILLARY WALLS FROM PATIENTS WITH DIABETES MELLITUS

Deposition of immunoglobulins or acute phase reactant (APR) proteins in the dermal and glomerular capillary walls from patients with diabetes mellitus was examined to determine whether development of microangiopathy in such patients was related to exudation and/or entrapment of these proteins. Skin and renal biopsy specimens were obtained from patients with diabetic nephropathy and diabetes mellitus without nephropathy. These biopsy samples were stained with FITC-labeled anti-human IgG, IgA, IgM, C3, APR proteins, and β-Hpoprotein antisera. Linear depositions of IgA, IgG and/or APR proteins were observed in the dermal and/or glomerular capillary walls from some patients with diabetic nephropathy or diabetes mellitus without nephropathy. It is indicated that deposition of such immunoglobulins in the dermal and glomerular capillary walls might be due to exudation and/or entrapment of these substances in patients with diabetes mellitus.     

Immunologic phenomena in herpes gestationis.

Immunofluorescence studies were performed in 12 cases of herpes gestations. Direct IF staining (performed in 10 of them) revealed a highly characteristic pattern, notably 1) Constantly BMZ deposits of complement component C3, 2) In most biopsy specimens also C4 and C5, 3) Deposits of C4, C5, properdin and IgG variable in different specimens of given patients. About half of the specimens examined contained properdin and about one third stained for IgG, 4) Findings of IgM, IgA, IgD and IgE were consistently negative, 5) Serum findings of BMZ antibodies in given cases were variable. In two cases circulating BMZ antibodies were detected in one of the samples examined. On the base of these findings it seems that HG is related to BP.     

Rapid Immunofluorescence Staining by Microwave Incubation in Patients with IgA Nephropathy

Abstract

The effect of microwave incubation on the immunofluorescence staining findings in renal tissues in patients with IgA nephropathy is described. Ten patients with IgA nephropathy were examined. The renal sections were incubated with FITC-labeled rabbit anti-human IgA, IgM, IgG, or C3 antisera in a microwave oven that was operated at 2,450 MHz with an output of 500 W. There was no significant difference in the distribution of IgA or C3 deposition in the glomeruli between incubation in the microwave for 3–7 sec and 4°C overnight incubation. However, the immunofluorescence intensity of IgA after microwave incubation was less than that after incubation at 37°C for 1 min to 2 hr or 4°C overnight incubation. The intensity or distribution of IgG and IgM deposition in the glomeruli was markedly less after microwave incubation than that after incubation of 4°C overnight. We conclude that rapid immunofluorescence by microwave incubation is useful in the examination of renal biopsy specimens, especially IgA and C3 staining findings in patients with IgA nephropathy. (The J Histotechnol 13:175, 1990)     

The role of mesangial complement in the hematuria of experimental IgA nephropathy

We sought to determine if codeposits of IgG and IgM and glomerular complement, observed in most cases of human IgA nephropathy, might be important for inducing hematuria. All combinations of three binary variables, the protein immunogen, the duration of oral immunization, and the protein used for intravenous challenge, were accommodated by eight groups of BALB/c mice in an active model of IgA nephropathy. Mice drank 0.1% solutions of either of two proteins for either 6 or 14 weeks, and then were challenged intravenously with either the same protein or the alternate protein. After 6 weeks, all mice had significant increases of serum IgA, IgG, and IgM antibody to the oral immunogen. At 14 weeks, IgG and IgM antibodies were reduced, presumably due to the onset of oral tolerance, but IgA titers persisted. Nearly all mice had mesangial deposits of IgA and oral immunogen. However, only mice immunized for 6 weeks and challenged with the same protein had significant IgG and IgM deposits (100%), C3 deposits (76%), and significant microhematuria. To distinguish between the role of IgG/IgM codeposits and C3 in the pathogenesis of the hematuria, we induced passive IgA nephropathy with immune complexes of monoclonal IgA anti-dinitrophenyl antibody, dinitrophenyl-bovine albumin as antigen, and one of two monoclonal IgG antibodies specific for dinitrophenyl; one of the IgGs fixes complement, the other does not. Despite comparable mesangial deposits of IgA, IgG, and antigen, only mice given immune complexes containing the complement-fixing IgG had glomerular C3 and hematuria. Furthermore, when mice depleted of serum complement via cobra venom factor were given immune complexes containing the complement-fixing IgG, no glomerular complement was observed and no hematuria ensued. We conclude that IgG/IgM codeposits in murine IgA nephropathy do not directly cause hematuria but do induce the deposition of complement, which is in turn required for glomerular injury.     

Solubilization of intraglomerular deposits of IgG immune complexes by human sera or gamma-globulin in patients with lupus nephritis.

A study of the solubilization of glomerular deposition of IgG immune complexes by sera from patients with lupus nephritis is described. Renal biopsy specimens were obtained from 11 patients with lupus nephritis, five patients with IgA nephropathy and one patient with minimal change nephrotic syndrome. These renal specimens were incubated with fresh, stored or heated sera from the same patients or healthy adults and human gamma-globulins at 37 degrees C for 1 h in plastic test tubes. The sections were stained with FITC conjugated heavy chain specific anti-human IgG or C3 antisera and then examined with a fluorescent microscope. The sections were also stained with FITC conjugated human gamma-globulins and rhodamine conjugated anti-human IgG, IgM or IgA antisera and then examined by double exposure under a fluorescent microscope. It was demonstrated that fresh human sera or gamma-globulins significantly solubilize glomerular immune deposits in patients with lupus nephritis in vitro. It was indicated that the solubilization of IgG glomerular deposits from patients with lupus nephritis does not depend on complement. It is postulated that solubilization of immune deposits in glomeruli requires the excess amounts of antigenic substances in patients with lupus nephritis.     

Detection of polymeric IgA in glomeruli from patients with IgA nephropathy.

A study on the detection of polymeric IgA in glomeruli from renal biopsy specimens in patients with IgA nephropathy is described. Renal biopsy specimens were obtained from patients with IgA nephropathy. These specimens were stained with FITC-labelled anti-human J chain antisera and then examined with a fluorescent microscope. The J chain was observed in the glomerular mesangium by immunofluorescent staining. In parallel studies, renal biopsy specimens were treated with citrate buffer (pH 3.2) and the 'eluate' was neutralized by sodium hydroxide. The eluate was labelled with iodine-125, and the radiolabelled 'eluate' was fractionated by sucrose density-gradient ultracentrifugation. Polymerized IgA in the 'eluate' obtained from patients with IgA nephropathy was found to sediment predominantly as 9S to 11S using a sucrose density gradient analysis. Polymeric IgA in the fractions of the density gradient analysis was determined by anti-human IgA and anti-human J chain antisera. It was demonstrated that IgA and J chain were eluted from the glomeruli in some patients with IgA nephropathy. It is concluded that IgA deposited in the glomeruli is composed of dimers and/or larger polymers of circulating IgA in some patients with IgA nephropathy.     

Activation of complement by renal tissues from patients with IgA nephropathy.

In a study of complement activation by renal tissues, renal biopsy specimens were obtained from patients with IgA nephropathy and other glomerular diseases. These specimens were incubated with freshly frozen guinea-pig serum, and the activation of guinea-pig complement systems was evaluated by immunofluorescent staining with FITC-conjugated anti-guinea-pig complement antisera. It was shown that the alternative pathway of the complement was activated in situ in renal tissues from patients with IgA nephropathy. it is suggested that analysis of in situ activation of complement in such patients is useful for elucidating the mechanism of complement activation in various glomerular diseases.     

Detection of immunoglobulins and other serum proteins in the dermal and glomerular capillary walls from patients with diabetes mellitus

Deposition of immunoglobulins or acute phase reactant (APR) proteins in the dermal and glomerular capillary walls from patients with diabetes mellitus was examined to determine whether development of microangiopathy in such patients was related to exudation and/or entrapment of these proteins. Skin and renal biopsy specimens were obtained from patients with diabetic nephropathy and diabetes mellitus without nephropathy. These biopsy samples were stained with FITC-labeled anti-human IgG, IgA, IgM, C3, APR proteins, and beta-lipoprotein antisera. Linear depositions of IgA, IgG, and/or APR proteins were observed in the dermal and/or glomerular capillary walls from some patients with diabetic nephropathy or diabetes mellitus without nephropathy. It is indicated that deposition of such immunoglobulins in the dermal and glomerular capillary walls might be due to exudation and/or entrapment of these substances in patients with diabetes mellitus.     

Binding of complement component C1q to anti-β2 glycoprotein I antibodies from patients with antiphospholipid syndrome

OBJECTIVE: To determine if anti-beta2 GPI reactive with surface-bound beta2 GPI can bind C1q, i. e. to determine whether surface-bound beta2 GPI-anti-beta2 GPI immune complexes can initiate the classical pathway of complement activation. METHODS: Beta2 GPI was bound to chemically-activated microtiter plates which had previously been shown to promote anti-beta2 GPI reactivity with bound beta2 GPI. Wells with surface-bound beta2 GPI (capped with bovine serum albumin) were then reacted with complement-inactivated sera from antiphospholipid syndrome patients (APS) or with control sera. Following removal of unbound serum components, the wells were incubated with biotinylated C1q and probed with peroxidase-conjugated avidin D. Bound C1q was detected at 450 nm using tetramethyl benzidine/peroxidase as a substrate system and expressed as absorbance units (Abs). RESULTS: The identified 20 APS with elevated anti-beta2 GPI: 4 with IgG only, 4 with IgM only, 1 with IgA only, 1 with IgG and IgA, 6 with IgG and IgM and 4 with IgG, IgA and IgM. C1q binding from 20 healthy controls was 0.039 +/- 0.029 (SD). Of the APS, 17/20 (85%) had Abs >5 SD above controls. The 3 APS with C1q Abs within normal limits had, respectively, IgM only (1), IgA only (1), and both IgG and IgM (1). Statistical analyses (Kruskal-Wallis followed by Dunn's post test) suggest differences in IgG and IgG + IgM groups compared to con (Kruskal-Wallis: p = 0.0002; Dunn's: con vs. IgG, p < 0.05; con vs. IgG + IgM, p < 0.01). CONCLUSIONS: Anti-beta2 GPI from APS appear to have a variable degree of C1q affinity. Those patients with strong C1q binding responses are likely to have an inflammatory component to their disease processes.     

STUDIES ON GLOMERULAR IMMUNE SOLUBILIZATION BY COMPLEMENT IN PATIENTS WITH IgA NEPHROPATHY

A study of the solubilization of glomerular immune deposits by serum or complement in patients with IgA nephropathy is described. Renal biopsy specimens were obtained from 15 patients with IgA nephropathy. These specimens were incubated with fresh and heated sera from healthy adults or with lyophilized complement components, i.e., C3 and C4, at 37°C for one hour in plastic tubes. The sections were then stained with fluorescein isothiocyanate (FITC)-labelled anti-human IgA antisera and examined by fluorescence microscopy. Normal sera showed a marked capacity to solubilize the glomerular immune deposits characteristic of IgA nephropathy. The solubilization capacity was reduced after inactivation and absorption of sera with anti-human C3 antiserum. Lyophilized C3 or C4 did not show any ability to solubilize such deposits. It was concluded that the solubilization of glomerular immune deposits may require whole active (fresh) components of complement related to the alternative pathway. ACTA PATHOL. JPN.     

Studies on glomerular immune solubilization by complement in patients with IgA nephropathy

A study of the solubilization of glomerular immune deposits by serum or complement in patients with IgA nephropathy is described. Renal biopsy specimens were obtained from 15 patients with IgA nephropathy. These specimens were incubated with fresh and heated sera from healthy adults or with lyophilized complement components, i.e., C3 and C4, at 37 degrees C for one hour in plastic tubes. The sections were then stained with fluorescein isothiocyanate (FITC)-labelled anti-human IgA antisera and examined by fluorescence microscopy. Normal sera showed a marked capacity to solubilize the glomerular immune deposits characteristic of IgA nephropathy. The solubilization capacity was reduced after inactivation and absorption of sera with anti-human C3 antiserum. Lyophilized C3 or C4 did not show any ability to solubilize such deposits. It was concluded that the solubilization of glomerular immune deposits may require whole active (fresh) components of complement related to the alternative pathway.