Autoantibodies against bactericidal/permeability-increasing protein in patients with cystic fibrosis

Analysis of intractable factors in chronic airway infections: role of the autoimmunity induced by BPI-ANCA

The role of anti-neutrophil cytoplasmic autoantibodies against bactericidal/permeability-increasing protein (BPI-ANCA) in chronic airway infections was investigated. The serum BPI-ANCA titer was correlated with the severity of clinical symptoms in patients with chronic airway infections (P < 0.01), and the serum BPI-ANCA titer decreased with the improvement of the clinical picture, compared with its deterioration (P < 0.05). The serum BPI-ANCA titer was significantly higher in patients with far-advanced lesions on chest X-rays than in patients with milder lesions (P < 0.01) and in patients with reduced respiratory function (P < 0.05). Also, the serum BPI-ANCA titer was significantly higher in patients with prolonged colonization of gram-negative bacteria than in those without prolonged gram-negative bacterial colonization (P < 0.05). When neutrophils from healthy volunteers were incubated with BPI-ANCA before stimulation with lipopolysaccharide (LPS), neutrophil elastase levels decreased in a dose-dependent manner (P < 0.01). The phagocytic activity of neutrophils was significantly inhibited by BPI-ANCA in a dose-dependent manner (P < 0.01). The above findings suggest that BPI-ANCA, an autoimmune factor, appears during the course of chronic airway infections, and that this autoimmune factor may make chronic airway infections more intractable, by inhibiting the phagocytic activity of neutrophils for gram-negative bacteria.

Clinical use of serological tests for antineutrophil cytoplasmic antibodies. What do the studies say?

Trustworthy and clinically useful laboratory test results depend on high quality laboratory knowledge and performance and on close collaboration with experienced clinicians. Just like a diagnosis can only be made by contrasting it to a number of differential diagnoses, a prototype autoantibody profile can only be recognized if autoantibodies that partially mimic the former are just as well-known. In antineutrophil cytoplasmic antibody (ANCA)-associated small vessel vasculitides the characteristic autoantibody profile can only be demonstrated by use of at least two different methodologies and an assay-specific cut-off selection that clearly distinguishes between strongly positive and disease control low positive to negative values. Local serum banks containing samples from patients with well-characterized chronic immunoinflammatory diseases and ANCA-associated vasculitides are needed for such important studies whether in-house or commercial assays are used.

Clinical value of antineutrophil cytoplasmic antibodies

This article presents a brief review of the clinical value of antineutrophil cytoplasmic antibodies (ANCA) in the diagnosis and management of patients with various forms of vasculitis. ANCA assay methodology and testing recommendations are reviewed. The patterns of reactivity of ANCA observed by indirect immunofluorescence, the antigens recognized by ANCA, and the sensitivity, specificity, and positive predictive value of ANCA for diagnosis of different vasculitides are described. In addition, the spectrum of drugs and nonvasculitic diseases that are associated with ANCA and need to be differentiated from true ANCA-positive vasculitides are reviewed. When properly utilized and cautiously interpreted, ANCA are a useful, noninvasive diagnostic tool in the differential diagnosis of vasculitis.

Anti-neutrophil cytoplasmic antibodies directed against the bactericidal/permeability-increasing protein (BPI) in pediatric cystic fibrosis patients do not recognize N-terminal regions important for the anti-microbial and lipopolysaccharide-binding activity of BPI

This study was performed to examine the prevalence and clinical correlates of bactericidal/permeability-increasing protein anti-neutrophil cytoplasmic antibodies (BPI-ANCA) in pediatric cystic fibrosis (CF) patients and to elucidate their possible role in CF pulmonary pathology. Sera of 27 CF patients were tested for ANCA by indirect immunofluorescence (IFT) and by enzyme-linked immunosorbent assay (ELISA) for ANCA sub-specificities. BPI-ANCA were examined by using standard ELISA for BPI, lipopolysaccharide-binding protein (LBP), and BPI/LBP fusion proteins to epitope map the main binding sites and look for cross-reactivity with LBP. Pulmonary function and serum concentrations of total immunoglobulin G (IgG) were measured and infections were diagnosed. In addition, release of reactive oxygen species (ROS) by neutrophil granulocytes was measured after stimulation with monoclonal BPI-ANCA. Using IFT, two patients showed atypical ANCA staining, six patients exhibited perinuclear ANCA staining, and no cytoplasmic ANCA staining was detected. Of 27 patients, 13 (48%) were BPI-ANCA (IgG) positive, and three were also immunoglobulin A (IgA) BPI-ANCA positive; one patient had ANCA against lactoferrin; and no proteinase 3 ANCA was detected in any of the patients. All BPI-ANCA bound to the C-terminal region of the molecule; none bound to the N-terminus or to LBP. There was no significant correlation between clinical data and the occurrence of BPI-ANCA in this cross-sectional study. Release of ROS from granulocytes was induced by monoclonal BPI-ANCA. Activation of neutrophils and possible modulation of BPI-mediated opsonophagocytosis and disposal of Gram-negative bacteria and lipopolysaccharides by BPI-ANCA raise the possibility that they contribute to pulmonary pathology in pediatric CF patients but intervention longitudinal studies in large groups of patients are needed to establish a causative association.

Antineutrophil cytoplasmic antibodies and associated diseases: a review of the clinical and laboratory features

There have been a number of recent advances in this field. First, the "International Consensus Statement on Testing and Reporting of Antineutrophil Cytoplasmic Antibodies (ANCA)" has been developed to optimize ANCA testing. It requires that all sera are tested by indirect immunofluorescent (IIF) examination of normal peripheral blood neutrophils and, where there is positive fluorescence, in enzyme-linked immunosorbent assays (ELISAs) for antibodies against both proteinase 3 (PR3) and myeloperoxidase (MPO). Testing will be further improved when international standards and common ELISA units are available. Second, new diagnostic criteria for the small vessel vasculitides that take into account ANCA-positivity and target antigen specificity as well as histologic features are currently being produced. Third, we understand that the complications associated with treatment of the ANCA-associated vasculitides are often more hazardous than the underlying disease, and regimens that use effective but less toxic agents are being evaluated. The factors associated with increased risk of relapse, however, remain incompletely understood. Finally, ANCA with specificities other than PR3 and MPO are present in many nonvasculitic autoimmune diseases. Their clinical significance is still largely unclear, and some of the target antigens are present in other cells as well as neutrophils and thus are not strictly "ANCA."

Autoantibodies directed against bactericidal/permeability-increasing protein in patients with cystic fibrosis: association with microbial respiratory tract colonization

BACKGROUND

Cystic fibrosis (CF) is associated with the appearance of serum autoantibodies directed against bactericidal/permeability-increasing protein (BPI).

OBJECTIVES

To determine the age-specific seroprevalence rates of anti-BPI-IgG and IgA in a population of patients with CF and to correlate anti-BPI antibody concentrations with microbial respiratory tract colonization and pulmonary function variables at the time of serum sampling and 6 years thereafter.

METHODS

Determination of BPI antibodies of the IgG and IgA isotypes using a commercial enzyme-linked immunosorbent assay in sera of a CF serum bank of 1992; correlation of anti-BPI antibody concentrations with age, clinical score, pulmonary function variables in 1992 and 1998, total serum immunoglobulin isotype concentrations and respiratory tract colonization with Pseudomonas aeruginosa and Aspergillus spp.

RESULTS

Seventy-one patients (age in 1992, 14.1 +/- 7.5 years) were studied. Reactivities for anti-BPI-IgG and IgA were found in 28 (39%) and 26 (37%) patients, respectively. The seroprevalence of anti-BPI-IgA, but not IgG, increased significantly with age. P. aeruginosa colonization was associated with elevated concentrations of anti-BPI-IgG (P = 0.003) and IgA (P = 0.037). There were significant negative correlations between pulmonary function variables (vital capacity, forced expiratory volume in 1 s) in 1992 and 1998, respectively, and concentrations of anti-BPI-IgG or IgA in a multiple regression analysis. Anti-BPI-IgG, but not IgA, remained significantly associated with P. aeruginosa colonization (P = 0.006) and with reduced vital capacity (P = 0.01) in 1998 after correction for total serum isotype concentration.

CONCLUSIONS

Anti-BPI-IgG are strongly associated with concurrent P. aeruginosa colonization and with long term restrictive pulmonary function abnormalities.

The prevalence and clinical significance of alpha 1-antitrypsin deficiency (PiZ) and ANCA specificities (proteinase 3, BPI) in patients with ulcerative colitis

Our aim was to determine the prevalence of the PiZ allele for alpha 1-antitrypsin (AAT) deficiency and some relevant antineutrophil cytoplasmic antibody (ANCA) specificities in patients with ulcerative colitis (UC), and explore a possible association between these markers. In addition, we studied the relation to disease extension and activity. Sera from 141 patients with UC (72 women) were analyzed while 50 blood donors and 54 patients with acute myocardial infarction served as controls. Serum samples were screened for PiZ with ELISA and phenotyped by isoelectric focusing. BPI-ANCA and PR3-ANCA were detected by ELISA. Results were that 8.5% (12/141) of the patients with UC were PiZ carriers, higher than expected in the general Swedish population (4.7%) (p = 0.03). There was a significant difference between PiZ-carriers and non-PiZ-carriers in the extension and severity of colitis (odds ratio = 4.1, confidence interval = 1.1, 14.9; p = 0.028, and odds ratio = 9.0, confidence interval = 1.1, 73.3; p = 0.015; respectively). BPI-ANCA and PR3-ANCA were detected in 20.5% (29/141) and 12% (17/141) (p < 0.05 compared with controls for all parameters). Occurrence of BPI-ANCA and PR3-ANCA was not related to extension or severity of colitis (p > 0.05 for both variables). We observed no association between PiZ-carrier status and occurrence of BPI-ANCA or PR3-ANCA. The increased frequency of heterozygosity for the PiZ variant of AAT deficiency among patients with UC might imply a role played by protease inhibitors for regulation of inflammation and immunologic response in UC.

Anti-neutrophil cytoplasmic antibodies (ANCA) against bactericidal/permeability-increasing protein (BPI) and cystic fibrosis lung disease

Persistent infection with Pseudomonas aeruginosa and inflammatory mechanisms play an important role in cystic fibrosis (CF) lung disease. ANCA against BPI, a potent host defence protein with anti-bacterial and anti-endotoxin properties, have been described in CF. We have assessed the relationship of anti-BPI antibodies to pulmonary disease severity in 148 CF subjects. IgA and IgG anti-BPI antibodies were found in 55.4% and 70.3% of CF patients, respectively, and higher levels were strongly associated with colonization with P. aeruginosa (P = 0.001 and 0.039 for IgA and IgG antibodies, respectively). IgA and IgG anti-BPI antibodies were independently associated with more severe lung disease as assessed by chest radiograph score (P = 0.023) and a significantly lower forced expiratory volume in 1 s (FEV1)% (P = 0.01). The pathophysiological relevance of the autoantibodies was investigated further by determining their epitope specificity and their effect on bacterial phagocytosis in vitro. Both isotypes of anti-BPI antibodies were specific for the C-terminus of BPI shown recently to be important for BPI-mediated opsonization, and in vitro affinity-purified anti-BPI antibodies significantly reduced BPI-induced phagocytosis of Escherichia coli compared with controls. These data indicate that anti-BPI autoantibodies are associated with colonization with P. aeruginosa and worse lung disease in CF. The inhibition of bacterial phagocytosis suggests that these autoantibodies may contribute to the persistence of P. aeruginosa in the CF lung and so play a role in perpetuating CF lung damage.

Heat treatment of normal human sera reveals antibodies to bactericidal permeability-inducing protein (BPI)

Heat treatment of normal sera to 56 degrees C for 30 min, a common procedure for the inactivation of viruses, e.g. HIV, reveals the presence of antibodies to neutrophil cytoplasm antigens (ANCA), as detected by indirect immunofluorescence on ethanol-fixed human neutrophils and by antigen-specific ELISA for BPI. Reactivity was not seen to the other common vasculitis-associated antigens proteinase 3 (PR3) or myeloperoxidase (MPO). The effect of temperature was maximal at 56 degrees C, with substantial antibody demonstrable after only 5 min at this temperature. In experiments using polyethylene glycol (PEG)6000 to remove immune complexes, the effect of heating could be abrogated by preincubation with 8% PEG, which suggested that these anti BPI antibodies might be complexed in sera. After passage of normal plasma over a protein G column, the acid-eluted fraction contained elevated levels of antibodies to BPI but not to other vasculitis-associated antigens such as PR3 or MPO, nor to glomerular basement membrane (GBM), the Goodpasture antigen which is recognized by the pathogenically important human antibodies shown to mediate nephritis in transfer experiments. Moreover the levels of anti-BPI in the IgG fraction could be augmented by preincubation with glycine pH 2.5 for 30 min. This anti-BPI activity could be inhibited by addition of the unbound material from the protein G column and this inhibitory material was not heat-labile at 56 degrees C. The molecular specificity of this autoreactivity was confirmed using recombinant BPI in coincubation experiments and the epitope localized to the C or N terminal moieties by the use of recombinant fusion proteins.

Anti-neutrophil cytoplasmic autoantibodies (ANCA) to bactericidal/permeability-increasing (BPI) protein recognize the carboxyl terminal domain

OBJECTIVES

to identify the region of bactericidal/permeability-increasing protein (BPI) recognized by anti-BPI ANCA.

METHODS

sera from 140 patients with a variety of clinical diagnoses (20 systemic vasculitis, 12 cystic fibrosis, 22 bronchiectasis/chronic obstructive airways disease, three diabetes mellitus, 13 chronic renal failure, 12 primary sclerosing cholangitis, eight ulcerative colitis, three Crohn's disease, seven cancer, and 40 other or unknown diagnoses) known to be reactive against native (nBPI), were screened by solid phase enzyme linked immunosorbent assay (ELISA) against a panel of recombinant fusion proteins; holo BPI (rBPI), recombinant lipopolysaccharide binding protein (rLBP), an N-terminal fragment of rBPI (rBPI21 ) and 'fusion' proteins containing the C- or N-terminal ends of BPI spliced with N-or C-ends of LBP, respectively.

RESULTS

a strong correlation was seen between the degree of reactivity to rBPI and the BPI C-terminal fusion protein, r=0.69, P < 0.001, as well as between nBPI and rBPI protein, r=0.55, P < 0.001, but not between nBPI and the N-terminal region of BPI (rBPI21), or proteins containing only the N-terminal fragment. Binding to proteins containing the BPI C-terminus was confirmed to be specific by fluid phase inhibition ELISA and Western blot analyses.

CONCLUSIONS

together these data suggest that circulating autoantibodies to BPI from patients with different diseases recognize the C-terminal region of BPI.

Recognition of bactericidal/permeability-increasing protein by perinuclear anti-neutrophil cytoplasmic antibody-positive sera from ulcerative colitis patients: prevalence and clinical significance

BACKGROUND

The aim of this study was to evaluate a) the role of bactericidal/permeability-increasing protein (BPI) as a possible antigen determining perinuclear anti-neutrophil cytoplasmic antibody (p-ANCA) reactivity in ulcerative colitis and b) the prevalence and clinical correlates of anti-BPI antibodies in patients with ulcerative colitis on the basis of their p-ANCA status.

METHODS

p-ANCA and anti-BPI antibodies were evaluated by means of indirect immunofluorescence and enzyme-linked immunosorbent assay methods in a group of 112 ulcerative colitis patients (including 42 patients subjected to proctocolectomy) well defined as far as their clinical features and p-ANCA status.

RESULTS

Anti-BPI antibodies were detected in 24% of non-operated patients and were significantly more frequent in p-ANCA-positive patients (32% versus 5% in p-ANCA-negative patients; P < 0.015). The prevalence of anti-BPI antibodies was similar in non-operated and operated patients and was high in men, in patients with an extensive and aggressive disease, and in patients developing pouchitis after surgery.

CONCLUSIONS

These data indicate that BPI is a neutrophil antigen frequently recognized by p-ANCA-positive ulcerative colitis sera. The presence of anti-BPI antibodies appears to identify further immunologic and clinical heterogeneity in ulcerative colitis.

Antineutrophil cytoplasmic antibodies as markers for systemic autoimmune disease

Antineutrophil cytoplasmic antibodies (ANCA) have been associated with systemic vasculitis for almost 15 years. Significant advances in our understanding of the ANCA phenomenon have occurred with recognition of broadening the spectrum of diseases associated with ANCA, identification of specific antigens recognized by ANCA, and development of antigen specific assays for clinical use. Nevertheless problems continue for the chest physician in interpretation of this test. Although antigen specific testing improves overall performance of the test, accurate assessment of pretest probability of disease is still important for effective use of ANCA testing.

Antineutrophil cytoplasmic antibodies in primary sclerosing cholangitis: defined specificities may be associated with distinct clinical features

PURPOSE

The clinical significance of antineutrophil cytoplasmic autoantibodies (ANCA) in primary sclerosing cholangitis has not been established. We investigated whether analysis of the antigenic specificities of ANCA is useful for delineating clinical subsets of the disease.

METHODS

Sixty-nine patients with primary sclerosing cholangitis were studied. The presence of ANCA was analyzed by indirect immunofluorescence. Antibodies directed against specific antigens--proteinase 3, myeloperoxidase, elastase, bactericidal/permeability-increasing protein, cathepsin G, and lactoferrin--were identified by enzyme-linked immunosorbent assay.

RESULTS

ANCA were detected by indirect immunofluorescence in 46 (67%) patients. In antigen-specific enzyme-linked immunosorbent assays, 37 (55%) of the 69 patients had antibodies to one or more antigens: 32 (46%) had antibodies to bactericidal/permeability-increasing protein, 16 (23%) had antibodies to cathepsin G, and 15 (22%) had antibodies to lactoferrin. Only 3 patients had antibodies to proteinase 3. Antibodies to myeloperoxidase or elastase were not detected. Twenty (29%) patients had antibodies to different antigens simultaneously. ANCA as detected by indirect immunofluorescence were not significantly associated with the presence of cirrhosis nor with the coexistence of inflammatory bowel disease. However, antibodies to bactericidal/permeability-increasing protein and cathepsin G were both associated with the presence of cirrhosis, and antibodies to lactoferrin were more frequently detected in patients with primary sclerosing cholangitis in conjunction with ulcerative colitis than in those without inflammatory bowel disease.

CONCLUSION

Defined specificities of ANCA in primary sclerosing cholangitis may be related to particular clinical features of the disease.

Anti-phagocyte antibodies and infection

Autoantibodies specific to the cytoplasmic components of neutrophils and monocytes are associated with vasculitis and other idiopathic inflammatory disorders. In this study, using enzyme-linked immunosorbent assay (ELISA) and immunofluorescence assays, sera from patients with acute and chronic infection were examined for the presence of anti-neutrophil and anti-monocyte antibodies: cystic fibrosis (n = 23), acute appendicitis (n = 22), tuberculosis (n = 26), acute gastroenteritis (n = 38), bronchiectasis (n = 9) and chronic granulomatous disease (n = 6). Sera from patients with Wegener's granulomatosis (n = 14), rheumatoid factor positive (n = 15) and healthy volunteers (n = 20) were used as positive and negative controls. In patients with chronic infection, using an ELISA assay, antibodies reactive with neutrophil or monocyte components (% reacting with monocyte components in parenthesis) were found in: 70% (39%) of patients with cystic fibrosis, 4% (38%) of patients with tuberculosis, 0% (33%) of patients with bronchiectasis and 0% (17%) of patients with chronic granulomatous disease. When these sera were examined using an immunofluorescence assay, all of the positive samples were found to react with the cytoplasmic component of neutrophils or monocytes. In patients with acute infection no antibodies (either IgG or IgM) were detected against neutrophils or monocytes. These findings imply that antibodies directed against neutrophil cytoplasmic components are predominantly associated with chronic pyogenic infection and antibodies specific to monocyte cytoplasmic components are predominantly associated with chronic granulomatous infection. This mirrors the findings in idiopathic inflammatory disease where anti-monocyte antibodies are associated with granulomatous disorders such as sarcoidosis, and anti-neutrophil antibodies are associated with neutrophilic disorders such as ulcerative colitis. These results suggest that chronic stimulation of phagocytes by infectious agents may result in the generation of a humoral response against phagocyte cytoplasmic components. This furthers our understanding of humoral immune responses against phagocytic cell components during infection.

Atypical, cytoplasmic and perinuclear anti-neutrophil cytoplasmic antibodies in patients with inflammatory bowel disease

Atypical, cytoplasmic and perinuclear anti-neutrophil cytoplasmic antibodies (x-, c- and pANCA, respectively) are associated with a variety of inflammatory diseases, including inflammatory bowel disease (IBD). Anti-neutrophil cytoplasmic antibodies are more common in patients with ulcerative colitis (UC) than in patients with Crohn's disease (CD). Most publications only refer to p- and cANCA in relation to IBD. We have prospectively evaluated the reactivity of sera from 58 patients with IBD and 10 healthy controls against human neutrophils with emphasis on the distinction of the ANCA types. The sera were incubated with ethanol- and formaldehyde-fixed granulocytes to differentiate between c-, p- and xANCA. The results showed that 10 of 24 patients with UC were positive for ANCA, whereas only one of 34 patients with CD was ANCA positive. These results correspond to a sensitivity of 42%, a specificity of 97%, a negative predictive value of 91% and a positive predictive value of 75% in UC. Of the 11 ANCA-positive sera, two showed a cytoplasmic staining pattern, three showed a perinuclear and six an atypical staining pattern. The disease activity was not correlated to either the ANCA titre or to the presence of ANCA in the serum. In conclusion, ANCA are of limited value in differentiating between UC and CD. Because the majority of ANCA in patients with IBD are xANCA, these ANCA should be explored by not only incubating on ethanol-fixed granulocytes, but also on formaldehyde-fixed granulocytes.

Antineutrophil cytoplasmic autoantibodies (ANCA) in children with cystic fibrosis

Anti-neutrophil cytoplasmic antibodies (ANCA) represent a useful diagnostic tool in patients with small vessel vasculitis. Circulating ANCA specific for bactericidal/permeability increasing protein (BPI) have been recently reported in adult patients with cystic fibrosis (CF), an autosomal recessive disorder caused by mutations in the cystic fibrosis transmembrane regulator (CFTR) gene with consequent impaired function of a transmembrane chloride channel. To contribute to the better understanding of the significance of ANCA in this disease, we investigated ANCA presence and antigenic specificity in children with CF. Results were correlated with clinical status, immunological data, age and genotype. The indirect immunofluorescence pattern of a total of 71 children with CF indicated that 31 were c-ANCA positive, while seven were p-ANCA positive. In further ELISA studies of ANCA antigenic specificity, 51 out of 66 investigated samples were positive for BPI, and 14 out of 28 were positive for proteinase 3 (PR3). We found an association between levels of antibodies against PR3 with age and Pseudomonas infection. We did not, however, find any correlation between CFTR genotypes, Pseudomonas infection or paediatric parameters and the level of anti-BPI antibodies. High positivity of anti-BPI antibodies were seen even among the youngest CF patients, before the development of clinical signs of CF, indicating that formation of ANCA might be a very early event in the disease. Both anti-BPI and anti-PR3 antibodies may play a significant, although variable role, in the pathogenesis of CF.

Role of the bactericidal/permeability-increasing protein in host defence

Much has been learned recently about the structure and function of 55 kDa bactericidal/permeability-increasing protein (BPI), a member of a genomically conserved lipid-interactive protein family. Analysis of BPI fragments and the crystal structure of human BPI have established that BPI consists of two functionally distinct domains: a potently antibacterial and anti-endotoxin amino-terminal domain (approximately 20 kDa) and a carboxy-terminal portion that imparts opsonic activity to BPI. A recombinant amino-terminal fragment (rBPI21) protects animals against the effects of Gram-negative bacteria and endotoxin. In man, rBPI21 is nontoxic and non-immunogenic and is in Phase II/III clinical trials with apparent therapeutic benefit.

Vasculitis and bronchiectasis in a patient with antibodies to bactericidal/permeability-increasing protein and alpha1-antitrypsin deficiency

A patient with alpha1-antitrypsin deficiency is reported herein; this subject developed aggressive bronchial disease and recurrent cutaneous vasculitis after pulmonary infection with Pseudomonas aeruginosa. Autoantibodies to neutrophil cytoplasmic antigens were detected, which produced granular cytoplasmic staining by indirect immunofluorescence with specificity for a newly characterized antigen: bactericidal/permeability-increasing protein (BPI). The bronchial disease and vasculitis improved, and the IgA anti-BPI titer fell after antipseudomonal treatment. This raises the possibility that anti-BPI antibodies contributed to both the bronchial disease and vasculitis.

Autoimmunity to polymorphonuclears: functional consequences of the binding of antibodies to membrane and cytoplasmic target antigens of polymorphonuclear leukocytes

Antineutrophil autoantibodies reacting with cytoplasmic antigens are associated with various types of vasculitides, whereas antibodies reacting with neutrophil membrane antigens are mostly related to autoimmune neutropenias. The aim of this study was the investigation of the effect of monoclonal antibodies (MoAbs) reacting with surface and cytoplasmic antigens of polymorphonuclear leukocytes (PMN) known to be targets for autoantibodies in human diseases. Blood of healthy volunteers was tested for several phagocytic functions in the presence of MoAbs against surface (CD16, CD11b, CD18, NB1) and cytoplasmic (proteinase 3; PR3) molecules. Candidacidal activity was significantly inhibited in the presence of all MoAbs but isotypic control. Phagocytic activity was inhibited by anti-CD11b and/or anti-CD18 MoAbs. Zymosan-induced chemiluminescence was reduced by MoAbs anti-CD16, CD18, and NB1, enhanced by anti-PR3 MoAb, and less enhanced by anti-CD11b. In conclusion, antimembrane antibodies diminished phagocytic functions at multiple steps; in contrast, anticytoplasmic MoAb promoted activation of oxidative burst in addition to impairment of microbicidal activity. This fact may be related to different pathogenic aspects of diseases associated with antimembrane and anticytoplasmic antibodies.

[Bactericidal permeability increasing protein (BPI-ANCA marked chronic inflammatory bowel diseases and hepatobiliary diseases]

BACKGROUND

Bactericidal permeability increasing protein (BPI) is an antibacterial product of neutrophilic granulocytes that can serve as target antigen for antineutrophil cytoplasmic antibodies (ANCA). The clinical associations of autoantibodies against BPI (BPI-ANCA) are essentially unclear.

PATIENTS AND METHODS

587 sera from patients with chronic inflammatory bowel diseases, inflammatory hepatobiliary diseases, primary systemic vasculitides and other rheumatological diseases were examined for BPI-ANCA by mono-specific ELISA and a standard indirect immunofluorescence test for ANCA. (ACD-CPR versus S-CPR). The treatment groups were similar with respect to age, sex, time interval from collapse to CPR, defibrillation and first epinephrine medication. There was no difference between the ACD group and the standard CPR group in terms of survival rates and neurologic outcome. No differences occurred concerning complications of CPR.

CONCLUSION

In our two-tiered EMS system with physician-staffed ambulances ACD-CPR neither improved nor impaired the survival rates and the neurological prognosis in patients with out-of-hospital cardiac arrest. Our results are in accordance with other studies carried out in EMS systems, with first tier call-response intervals between 4 and 6 min.

RESULTS

The prevalence of BPI-ANCA was 43% in ulcerative colitis, 23% in Crohn's disease, 35% in primary sclerosing cholangitis, 25% in primary biliary cirrhosis and 29% in autoimmune hepatitides. In a spectrum of systemic vasculitides, inflammatory joint diseases and collagen vascular diseases the prevalence was only 3 to 11%. In contrast to PR3-ANCA and MPO-ANCA, BPI-ANCA was not associated with a particular pattern of fluorescence in the immuno-fluorescence test on ethanol- and formalin-fixed neutrophils.

CONCLUSION

This study shows that BPI-ANCA is the third ANCA specificity, besides PR3-ANCA and MPO-ANCA, with a limited spectrum of clinical associations. The diagnostic and prognostic relevance of BPI-ANCA in the above clinical conditions is being examined prospectively.

Use of native and recombinant bactericidal/permeability-increasing proteins (BPI) as antigens for detection of BPI-ANCA

Anti-neutrophil cytoplasmic antibodies (ANCA) against native bactericidal/permeability-increasing protein (nBPI) have gained increasing diagnostic significance in inflammatory bowel disease and cystic fibrosis. However, routine detection of BPI-ANCA requires pure antigen in large quantities. As nBPI is difficult to isolate and is very susceptible to proteolytic cleavage with subsequent epitope loss, it was the aim of this study to determine whether recombinant BPI (rBPI) can be used as an alternative to nBPI as target antigen for ANCA in diagnostic procedures. Therefore, 93 BPI-ELISA-positive sera and controls were compared in different ELISAs using nBPI, rBPI, unglycosylated rBPI and a 21-kDa amino-terminal fragment of rBPI. ELISA results were confirmed by immunoblotting and all sera were tested in indirect immunofluorescence (IFT). There was an 88% (82/93) agreement in recognition of nBPI and rBPI by ANCA in both ELISA systems, yet the quantitation of BPI-ANCA in relative units showed a less optimal result and correlated only by 45% (p < 0.01). Most sera recognized nBPI, rBPI and unglycosylated rBPI equally suggesting that glycosylation has no influence on antigen recognition. Only two sera were positive for the 21-kDa nBPI indicating that the binding sites for ANCA are either conformational epitopes and/or are located mainly on the carboxy-terminal part of the BPI molecule. Most BPI-ELISA-positive sera were negative in IFT (43%), but a perinuclear (pANCA, 30%), a cytoplasmic (cANCA,10%) or an atypical ANCA (aANCA, 2%) staining pattern, as well as a cytoplasmic pattern only on formaldehyde-fixed granulocytes (13%) were also observed. Overall, no characteristic pattern was seen for BPI-ELISA-positive sera in IFT. Taken together, these data suggest that rBPI offers an excellent alternative to nBPI for broad-based BPI-ANCA ELISA and will be of great value in further investigations of BPI-ANCA interactions.

A comprehensive method to purify three major ANCA antigens: proteinase 3, myeloperoxidase and bactericidal/permeability-increasing protein from human neutrophil granule acid extract

Indirect immunofluorescence (IIF) techniques have shown that anti-neutrophil cytoplasm autoantibodies (ANCA) are useful serological markers for certain small vessel vasculitides and the non-vasculitic inflammatory disorders. ELISA procedures, using purified molecules as solid phase ligands, helped to identify proteinase 3 (PR3) and myeloperoxidase (MPO) as two major ANCA antigens; and recently we characterised bactericidal/permeability-increasing protein (BPI) as another important ANCA antigen. ANCA against these three antigens are associated with different clinical disorders. Therefore purified antigens are needed to determine these different autoantibody specificities in order to help diagnosis and guide treatment. Here we describe a method using Orange-A dye ligand chromatography and cation exchange chromatography for the sequential purification of PR3, MPO and BPI, from the same starting material, an acid extract of normal human neutrophil granules. After separation the three antigens were free of contamination by each other and no traces were found of other known minor ANCA antigens.