Mechanism of action of factor D of the alternative complement pathway.

Factor D (C3 proactivator convertase) of human serum has been shown to be absolutely necessary for alternative pathway function, for activation of the C3/C5 convertase of that pathway and not to be a subunit of this enzyme. Factor D was found to be present in human plasma in active form only, at a concentration of 2 microgram/ml, and not to be controlled by plasma protease inhibitors or by spontaneous decay. Unlike trypsin, factor D cleaves and activates factor B only when it is in Mg++-dependent complex with C3b, has no esterolytic activity, and is unable to cleave the B chain of insulin. The alleged functional and antigenic relationship of factor D to alpha-thrombin could not be verified. The results of this study led to the description of the mechanism of action of factor D in terms of the cryptic site hypothesis.

Differential regulation of tumor necrosis factor-alpha-converting enzyme and angiotensin-converting enzyme by type I and II interferons in human normal and leukemic myeloid cells.

The transmembrane metalloproteases angiotensin-converting enzyme (ACE) and tumor necrosis factor-alpha (TNF-alpha)-converting enzyme (TACE/ADAM-17) have been associated with inflammation, cancer progression and angiogenesis. Few investigations into the regulation of these enzymes by physiological stimuli have been reported. In this study, we investigated the influence of interferons (IFNs) type I (alpha, beta) and II (gamma) on ACE and TACE expression of human leukemic NB4 cells and monocytes. We assessed the expression of proteases by reverse transcriptase-polymerase chain reaction, enzyme-linked immunosorbent assay and immunofluorescence analyses. IFNgamma, but not type I IFNs, upregulated membrane ACE in a dose- and time-dependency and this was reflected by the increase of ACE enzymatic activity and ACE mRNA. ACE upregulation was dependent on protein synthesis. Treatment of the interferon responsive factor 1 (IRF1)-unresponsive HepG2 cell line with IFNgamma did not affect ACE expression, thus suggesting the participation of the IRF1 signaling pathway in IFNgamma-mediated ACE upregulation in myeloid cells. In contrast, both types of IFNs, in a dose- and time-dependent manner, downregulated surface TACE without affecting TACE transcript. Soluble TACE was not detected in the medium of IFN-treated cells. IFNgamma-mediated decrease of surface TACE in NB4 cells was reversible, and correlated with an increase in intracellular TACE, suggesting that cell surface TACE was internalized in response to IFNs. These findings, showing the presence of IFN-dependent controlled mechanisms by which ACE and TACE levels are regulated in human normal and leukemic myeloid cells, may have implications in the context of current investigations on the therapeutic potential of IFNs.

Nephritic factor of the classical pathway of complement: immunoglobulin G autoantibody directed against the classical pathway C3 convetase enzyme.

A factor, functionally characterized by its capacity to stabilize the normally labile classical pathway C3-converting complex of the classical pathway of complement, has been isolated from the serum of one patient with a case of acute glomerulonephritis, subsequent to a cutaneous infection. The factor confers long-lived stabilization of classical pathway C3 convertase complexes formed both in the solid (sensitized sheep erythrocytes bearing activated C1 and the classical pathway C3 convertase) and fluid phase. The half-life of such stabilized C3-cleaving enzymes extended beyond several hours at 37 degrees C. The stabilizing activity was associated with a protein fraction immunochemically identified as immunoglobulin (Ig)G, a sizeable population of which exhibited a gamma chain of 60,000 daltons. The IgG-associated stabilizing activity was found to bind to the classical pathway C3 convertase enzyme via a fragment bearing the antigen-binding site of the molecule [F(ab)(2) and F(ab)]. Such binding was demonstrable for classical pathway and not for alternative pathway C3 convertase. Thus, the stabilizing factor behaves like an autoantibody to the C3-converting complex of the classical pathway of complement. The binding of the antibody to the enzyme affords protection of the latter against decay-degradation. By analogy with the nephritic factor of the alternative pathway situation where IgG autoantibodies specifically bind to alternative pathway C3 convertase enzymes and protect them from degradation, the functionally unusual IgG in our patient was designated as the nephritic factor of the classical pathway. Indirect evidence suggests that nephritic factor of the classical pathway-IgG might be of the IgG3 subclass.

Evidence for integrins other than beta 2 on polymorphonuclear neutrophils: expression of alpha 6 beta 1 heterodimer.

The expression of non-beta 2 integrins on polymorphonuclear neutrophils (PMNs) was analyzed by immunoprecipitation and flow cytometry using platelet-free PMN preparations and anti-Fc gamma R blocking mAbs. No beta 3 integrin was detected with six anti-beta 3 mAbs. Conversely, integrin beta 1 chain was present on PMNs, although at low level, and could be distinguished from platelet beta 1 by SDS-PAGE. The MW differences disappeared after N-glycanase treatment. PMNs express only 2500 molecules of beta 1 per cell and this expression is not modulated by agonists such as phorbol myristate acetate, formylmethionyl-leucyl-phenylalanine, granulocyte-macrophage colony-stimulating factor, or tumor necrosis factor alpha, which enhance CD11b expression, or by interferon-gamma or transforming growth factor beta. PMNs were found to express alpha 6 associated with beta 1, and no reactivity was observed with various anti-alpha 1, anti-alpha 2, anti-alpha 3, anti-alpha 4, anti-alpha 5 or anti-alpha V mAbs. In conclusion, although other leukocytes express various beta 1 integrins, which mediate cell interactions with ECM proteins, PMNs appear to express only the laminin receptor alpha 6 beta 1. PMN interactions with non-laminin ECM ligands thus seem to be mediated either exclusively by beta 2 integrins or by nonintegrin molecules.

Lupus nephropathy and pregnancy. Report of 104 cases in 36 patients.

The reciprocal influence of lupus nephropathy on the outcome of pregnancy and of pregnancy on the course of renal involvement was studied retrospectively in a series of 106 pregnancies observed during the past two decades in 36 patients with lupus nephropathy. The overall incidence of live births, corrected for induced abortions, was 54 (84%) in 64 pregnancies that began before clinical onset of systemic lupus erythematosus (SLE), 20 (87%) in 23 pregnancies that began after onset of SLE, and only four (57%) in seven cases where SLE was first manifested during or after gestation. Relapse or exacerbation of disease activity occurred in 12 (46%) of 26 pregnancies antedated by clinical onset of SLE, more frequently during gestation than post partum, with two cases (8%) of irreversible deterioration of renal function; clinical exacerbation of lupus disease was observed in 11 (66%) of 15 cases where SLE was clinically active at the time of conception, and in only one (9%) of 11 cases where SLE nephritis was in stable clinical remission for at least five months before conception. The data indicate that successful outcome of pregnancy may be expected even in the more severe forms of lupus nephritis if gestation begins after a sustained, complete clinical remission.

Immune-complexes solubilization: effect of antigen-antibody ratio and relative role of alternative and classical complement pathways.

Insoluble immune-complexes (IC) are solubilized by complement. A functional alternative pathway (AP) is required for solubilization. Classical pathway (CP) has an enhancing effect, but the effect of antigen-antibody (Ag-Ab) ratio and the relative role of AP and CP at these different Ag-Ab ratios is controversial. We reinvestigated these factors in a human model (IC prepared with tetanus toxoid and affinity purified human Ab solubilized by normal serum--NHS). We present evidence that (1) IC prepared at Ag excess are only partially solubilized. (2) IC prepared at large Ag excess are not solubilized by AP. (3) AP prepared at Ab excess are solubilized exclusively by AP. (4) IC prepared at equivalence are solubilized by AP and CP acting in synergy.

Bimodal distribution of proteinase 3 (PR3) surface expression reflects a constitutive heterogeneity in the polymorphonuclear neutrophil pool.

Proteinase 3, which is known as an intracellular serine protease of neutrophils, was detected at the surface of a subpopulation of freshly isolated PMN. The proportion of PR3-positive and -negative PMN, observed by flow cytometry with anti-PR3 mAbs or ANCA autoantibodies, varies among individuals but is extremely stable for each individual over prolonged time periods. After PMN degranulation by FMLP with cyt. B, membrane PR3 expression increases but the proportion of low and high PR3-expressing cells remains stable. The existence of a subset of PMN which spontaneously expresses PR3 and varies among individuals, may be relevant to the pathogenesis of anti-PR3 ANCA autoantibody-related vasculitis.

Characterization of a recombinant proteinase 3, the autoantigen in Wegener's granulomatosis and its reactivity with anti-neutrophil cytoplasmic autoantibodies.

Using the baculovirus/insect cells system, we have expressed a recombinant proteinase 3 (PR3) -- the neutrophil-derived serine protease autoantigen in Wegener's granulomatosis -- as a glycosylated intracellular and membrane-associated protein. Oligosaccharides accounted for the difference in molecular weights between recombinant (34 kDa) and neutrophil-PR3 (29 kDa). Whereas rabbit-anti-PR3 IgG recognized both recombinant and neutrophil-derived PR3, autoantibodies from Wegener patient sera recognized only neutrophil-derived PR3. Although oligosaccharides were not involved in PR3 epitope recognition, autoantibodies did not recognize the amino acid primary structure of recombinant PR3. Improper disulfide bond formation and/or lack of post-translational events in insect cells, may affect the conformation and/or lack of post-translational events in insect cells, may affect the conformation of PR3, precluding its reactivity with sera from WG patients.

Renal vascular lesions in lupus nephritis.

We retrospectively studied the prevalence, histologic features, clinical correlations, and long-term outcome of the intrarenal vascular lesions of lupus nephritis (LN) in a series of 169 renal biopsies performed between 1980 and 1994 in 132 patients with systemic lupus erythematosus. The most common vascular lesions were nonspecific sclerotic changes, found in 37% of the biopsies (24% if only the cases with moderate to severe changes are considered). The other common vascular lesions were "immunoglobulin microvascular casts," found in 24% of the biopsies. Vasculitis and thrombotic microangiopathy were rare lesions and were seen in only 4 (2.4%) and 1 (0.6%) cases, respectively. Isolated sclerotic vascular changes were present in biopsies from older patients with a longer duration of LN, compared with the group with no vascular lesions, and were associated with a significantly higher prevalence of hypertension. Overall, however, the long-term renal and patient survival of this group did not differ significantly from that of the patients without vascular changes. Immunoglobulin microvascular casts (IMCs) ("lupus vasculopathy") were characterized by the presence of immunoglobulin deposition within the glomerular capillaries and small arterioles. In the present study we extensively investigated the morphologic and immunologic features of this lesion. The lesions were notable for the absence of endothelial or parietal vascular lesions and of fibrin, platelets, and leukocytes, which indicates that thrombosis is not involved in the vascular obstruction. According to our data immunoglobulin precipitation in the microvasculature seems to play a central role in the pathogenesis of this lesion, which is why we propose the term "immunoglobulin microvascular casts." In general, IMCs were associated with the most severe and active forms of diffuse proliferative lupus nephritis (World Health Organization [WHO] class IV). However our data show that, in contrast to previous studies, the long-term outcome of patients with IMCs is not worse than that of other patients with class IV LN. It may even be somewhat better, suggesting that this type of lesion may reverse with immunosuppressive therapy. In addition, we did not find any association between the presence of IMCs and the lupus anticoagulant, IgG anticardiolipin antibodies, or extrarenal vascular manifestations. Concerning vasculitis and thrombotic microangiopathy, our results confirm that their occurrence is quite rare in-lupus nephritis. The outcome of our 4 patients with vasculitis was not particularly poor, which could be related to early and/or aggressive treatment. Taken as a whole, our data confirm that the presence of active and severe forms of diffuse proliferative LN (WHO class IV) carries a worse prognosis compared with the other forms of LN. In our study, and in agreement with previous reports (23), the long-term renal survival of patients with class IV LN was significantly worse than that of patients with other forms of LN, with a 10-year renal survival of 70% compared with 85%, respectively. However our data do not support the conclusions of some previous studies that the presence of intrarenal vascular lesions is a marker of poor renal prognosis in lupus nephritis. More precisely, our data show that the somewhat poorer renal outcome observed in patients with IMCs is related to the fact that in most cases these lesions are associated with class IV lupus nephritis, and not related to the presence of the vascular lesion per se.

A one-step procedure for preparation of classical pathway (C1q) and alternative pathway (factor D) depleted human serum.

A simple method for preparation of a serum depleted in both C1q and Factor D is described. The hemolytic activities of both pathways are completely abolished and can be fully restored using the respective purified complement components. Furthermore, this serum is useful for studying cell systems since blocking either complement pathway does not require chelating agents.

The value of indirect immunofluorescence and solid phase techniques for ANCA detection. A report on the first phase of an international cooperative study on the standardization of ANCA assays. EEC/BCR Group for ANCA Assay Standardization.

This study describes the results of phase I of an international effort to develop and standardize assays for the detection of anti-neutrophil cytoplasmic antibodies (ANCA). 12 sera, four of which were selected for their potential to cause problems in the detection of various ANCA specificities, were analyzed in the standard indirect immunofluorescence (IIF) test and in ELISAs for ANCA routinely performed in the seven participating laboratories. The IIF methodology differed with respect to the dilution of the serum being screened and the concentration of the conjugate used. Results from sera with high ANCA titers were similar, although the quantitative values could not be compared. In sera containing rheumatoid factor and anti-nuclear antibodies (ANA), ANCA-unrelated staining patterns were observed. Six antigen preparations were used in ELISA for the detection of cANCA. In ELISA with purified proteinase-3 all three cANCA sera were positive, but not anti-myeloperoxidase (MPO) or anti-lactoferrin (LF) positive sera. The other assays were less sensitive or gave inconsistent results. Various preparations of purified MPO and LF used in ELISA were readily recognized by anti-MPO and anti-LF positive sera. From this study it can be concluded that the IIF test, although performed with different methods, shows comparable results using strongly positive sera. In general solid phase assays for cANCA detection are not well standardized and need improvement although the purified proteinase-3 ELISA is possibly an exception. MPO and LF can be used in ELISA procedures for the detection of pANCA-related antibodies.

Determination of anti-neutrophil cytoplasm antibodies (ANCA) specificity by immunofluorescence on chronic myelocytic leukemia cells.

ANCA positive sera, detected by the standard immunofluorescence method, derived from 37 patients with vasculitis were studied using formalin-acetone fixed chronic myelocytic leukemia cells (CML). All 37 sera were positive on CML cell smears. Furthermore formalin-actone fixation selectively impaired antinuclear antibody binding without reducing ANCA staining and thus facilitated differentiation of these autoantibodies which is often difficult with the standard immunofluorescence method. Two unequivocal and mutually exclusive ANCA binding patterns were identified using the CML smears: (1) type I with diffuse granular binding confined to the polymorphonuclear (PMN) cell lineage and preferentially staining immature cells; (2) type II with similar binding to the PMN cell lineage and, in addition, granular staining of the basophils. All type I antibodies were associated with a c-ANCA pattern suggesting that the major antigen recognized by these antibodies, recently identified as proteinase 3, is not detectable in basophils. The type II pattern was detected in both p-ANCA (84%) and c-ANCA (16%) positive sera. The type I sera remained positive on PMN cells from a myeloperoxidase (MPO) deficient subject and anti-MPO antibodies could not be detected in this group by ELISA. Conversely the type II pattern occurred in the presence of anti-MPO antibodies identified by immunofluorescence, ELISA and dot-blot with the exception of a single serum with antilactoferrin antibody. Type I binding only was observed in Wegener's granulomatosis (WG) but both patterns were found in microscopic polyarteritis (MPA) and rapidly progressive glomerulonephritis (RPGN).

Development and standardization of solid phase assays for the detection of anti-neutrophil cytoplasmic antibodies (ANCA). A report on the second phase of an international cooperative study on the standardization of ANCA assays.

Anti-neutrophil cytoplasmic antibodies (ANCA) are diagnostic markers for systemic vasculitis. They are classically detected by an indirect immunofluorescence test using normal donor neutrophils as substrate. This assay lacks antigenic specificity and is not quantitative. The 'EC/BCR Project for ANCA Assay Standardization' is an international collaboration study with the aim to develop and standardize solid phase assays for ANCA detection. In this part of the study the isolation and characterization of proteinase-3 and myeloperoxidase, the two main target molecules for ANCA, and the development and standardization of ELISAs with these antigens are described. Six laboratories successfully isolated purified proteinase-3 preparations that could be used. Three of these preparations, together with one myeloperoxidase preparation, were subsequently used for ANCA testing by ELISA. The ELISA technique was standardized in two rounds of testing in the 14 participating laboratories. The coefficient of variation of these new assays decreased from values of approx. 50% in the first round to approx. 20% in the second round. We conclude that purified proteinase-3 and myeloperoxidase can be used in standardized ELISAs for ANCA detection. Whether such procedures offer advantages over the IIF test will be determined in a prospective clinical study.

POEMS syndrome presenting as systemic sclerosis. Clinical and pathologic study of a case with microangiopathic glomerular lesions.

A rare form of plasma cell dyscrasia characterized by the various association of polyneuropathy, organomegaly, endocrinopathy, monoclonal protein, and skin changes has been termed POEMS syndrome. The pathogenesis of the multisystemic features of this syndrome remains unclear. Herein is reported a case of POEMS syndrome with striking clinical similarities with scleroderma, and microangiopathic glomerular lesions, as well as diffuse perivascular non-amyloid deposits, which could explain certain features of the syndrome, including peripheral nerve demyelination. It is proposed that a pathogenic role might be played by a non-immunoglobulin vasculotoxic component.

Allogeneic lymphocyte-dependent antibodies (LDA). Specificity of Fc receptors.

Cellular receptors for the Fc fragment of IgG have been studied by the erythrocyte antibody (EA) rosette technique using either human red blood cells coated with anti-D IgG alloantibodies or pigeon red blood cells coated with aggregated IgG. Human lymphocytes were shown to form 4 to 35% of anti-D EA rosettes and 15% of E-aggregated IgG rosettes. Anti-D EA rosette values depended closely upon the amount and the source of anti-D antibodies, Ripley's type antisera giving the highest percentage of rosettes. Cell filtration through a nylon-wool column, a procedure known to remove B cells, caused a complete depletion of E-aggregated IgG rosettes and significant but only partial decrease of anti-D EA rosettes. A low but significant percentage of double rosettes were formed when anti-D-coated erythrocytes were mixed with aggregated IgG coated red blood cells or sheep red blood cells. Removal of EA-rosette-forming cells by passage on a Ficoll-Hypaque gradient K cell activity (assessed by lymphocyte-dependent antibody cytotoxicity using anti-HLA antibody-coated target cells) even when forming rosettes at low levels of erythrocyte sensitization with anti-D serum. Conversely, B cell markers (erythrocyte antibody complement rosettes or surface Ig) were only decreased at high levels of erythrocyte sensitization and remained unaffected after depletion of EA-rosette-forming cells formed at low levels of erythrocyte sensitization. These data suggest the existence of several populations of Fc receptor-bearing cells in human peripheral blood which may be differentiated according to the degree of erythrocyte IgG sensitization. Rosettes made with low concentrations of anti-D serum are mainly formed by non-B cells endowed with K cell activity, whereas those formed with high concentration of anti-D serum include B cells, monocytes, and K cells.

Granulomatous renal disease in a patient with common variable immunodeficiency.

Common variable immunodeficiency (CVID), the most common cause of primary hypogammaglobulinemia, is characterized by a decreased serum immunoglobulin level, recurrent infections, and the occurrence of various autoimmune diseases. Granulomatous disease has been reported previously in several patients with CVID, with granuloma occurring in the lymph nodes, spleen, liver, central nervous system, and bone marrow. We report the first published case of renal granulomatous disease in a CVID patient presenting with subacute renal failure. Renal function partially recovered after corticosteroid treatment and intravenous immunoglobulin infusions. The pathogenesis of granulomatous disease in CVID is unclear but may involve monocyte and T-cell abnormalities.

General toxicity of water-soluble iodinated contrast media. Pathogenic concepts.

Despite many studies, the mechanism of the general accidents induced by the intravascular injection of water-soluble iodinated contrast media remains unclear. Two theories are proposed; until now, they have not been related to each other. Lalli emphasizes the role of a cerebral impact related to stress, which induces a chain of accidents that are perhaps more aggressive when the molecules cross the blood-brain barrier. Lasser has proposed a theory based on the biochemical catastrophies secondary to the damage of the vascular endothelium and the activation of the Hageman's factor XII. A true anaphylaxis has not been proven: specific immunoglobulins are only exceptionally found, and an actual primary activation of the complement system pathway with mediator release is a controversial phenomenon in vivo. The anaphylactoid collapses result from a chemotoxic effect that might be decreased by several kinds of pharmaceutical premedications; none of them are constantly efficient. The new low osmolar molecules have a very low general toxicity, but their use does not guarantee the lack of anaphylactoid reactions.

Persistence of antineutrophil cytoplasmic antibodies (ANCA) in asymptomatic patients with systemic polyarteritis nodosa or Churg-Strauss syndrome: follow-up of 53 patients.

OBJECTIVE: We retrospectively analyzed the significance of persistent ANCA positivity after clinical remission in 53 consecutive patients with histologically and/or angiographically proven polyarteritis nodosa (PAN), or Churg-Strauss syndrome (CSS) followed between 1981 and 1993. METHODS: ANCA were detected using an immunofluorescence assay and ELISA: Each patient met the American College of Rheumatology 1990 criteria for PAN or CSS. Clinical and biological evaluations were always essential factors in the decision to intensify therapy. RESULTS: ANCA were initially present in 15 patients (28.3%): 3/26 (11.5%) with HBV-related PAN, 6/18 (33.3%) with PAN of unknown etiology and 6/9 (66.7%) with CSS. Five patients remained ANCA-positive after clinical remission: 3 with PAN (one of them relapsed) and 2 with CSS who both relapsed. Among the 12 patients who died during follow-up, only 1 (8.3%) was initially ANCA-positive. Fifteen of the 41 survivors (29.2%) were ANCA-positive. CONCLUSION: Persistence of ANCA positivity in PAN and CSS may be a marker of an underlying disease process, but does not adequately reflect disease activity and, thus, in no case should be the only indication for therapeutic intensification.

Clinical spectrum associated with ANCA of defined antigen specificities in 98 selected patients.

UNLABELLED: From 1987 to 1991, 2500 sera were tested for presence of anti-neutrophil cytoplasmic antibodies (ANCA) by standard indirect immunofluorescence (IIF) and specific proteinase 3 (PR3) and myeloperoxydase (MPO) ELISA. Clinical and histological data leading to precise diagnosis were retrospectively obtained in 98 patients with ANCA positivity by IIF and then a comparative study based on ANCA specificity was performed. Vasculitis was present in all cases. Among patients with anti-PR3 (n = 38), 19 had Wegener's granulomatosis (WG), 15 microscopic polyarteritis (mPA), 2 idiopathic necrotizing and crescentic glomerulonephritis (NCGN) and 2 relapsing polychondritis (RP). Among patients with anti-MPO (n = 45), 26 had mPA, 3 classical polyarteritis nodosa (PAN), 5 WG, 8 NCGN, 2 systemic lupus erythematosus (SLE) and one Churg-Strauss syndrome (CSS). Negative MPO and PR3 specific ELISA despite positive IIF were observed in 15 patients (13 WG, 1 mPA, 1 PAN). In the PR3 group, males predominated (66%) and the mean age was 49 years (range 13-85); in the MPO group, females predominated (62%) and the mean age was 57 years (range 13-85). These differences were statistically significant (p < 0.05). Renal involvement was present in 92% of patients and renal biopsy showed pauci-immune necrotizing and crescentic glomerulonephritis in nearly all cases. PR3 specificity was associated with frequent eye involvement (32%) and presence of granulomas (45%), but was not associated with other autoantibodies. MPO specificity was associated with a higher prevalence of pulmonary hemorrhage (40%) and various autoimmune disorders, especially antinuclear antibodies. Cholestasis was observed in 50% of WG with negative MPO and PR3 ELISA. Renal and patient survival at the 75th percentile was 15 months with MPO-ANCA and 16 months with PR3, and was similar for patients with WG and mPA. Relapses occurred in 20% of patients with anti-MPO and 36% of patients with anti-PR3. Serological follow-up was obtained in 44 patients. With immunosuppressive treatment, ANCA disappeared in 66% of cases and this disappearance was always associated with absence of disease activity. IN CONCLUSION: 1. This study confirms that the presence of ANCA is a good marker of vasculitis. 2. Despite some clinical differences, MPO and PR3-associated vasculitis have a similar prognosis. 3. The titer of ANCA determined by ELISA is not correlated with the severity of vasculitis but disappearance of ANCA is always associated with absence of disease activity.

Methods of detection of anti-cathepsin G autoantibodies in human.

Anti-cathepsin G antibodies have been detected by using three different methods. i) Binding to azurophilic granules constituents after separation of purified alpha-granules on Matrex gel Orange A chromatography according to Kao. ii) Binding to azurophilic granules freezed and thawed after coating on ELISA plates. iii) Binding to purified cathepsin G in ELISA assay. Anti-cathepsin G antibodies were observed patient's sera with ulcerative colitis, primary sclerosing cholangitis, primary biliary cirrhosis and autoimmune hepatitis but not in controls or patients with chronic viral hepatitis or vasculitis.