CAN YOU SEE MY BPI21? Perhaps Not.....Hmmmmmmmm........>>
>>Following from medline...............>>>>>>>>>>>>>>>
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Antineutrophil cytoplasmic autoantibodies (ANCA) in children with cystic fibrosis.
Sediva A, Bartunkova J, Kolarova I, Hrusak O, Vavrova V, Macek M Jr, M-Lockwood C, Dunn AC
Institute of Immunology, University Hospital Motol, Charles University, Prague, Czech Republic. Anna.Sediva@lfmotol.cuni.cz
[Medline record in process]
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.
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Use of native and recombinant bactericidal/permeability-increasing proteins (BPI) as antigens for detection of BPI-ANCA.
Schultz H, Csernok E, Johnston TW, Lockwood CM, Gross WL
Department of Rheumatology, University of Lubeck, Rheumaklinik Bad Bramstedt GmbH, Germany.
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.
PMID: 9294593, UI: 97440286
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Autoantibodies against bactericidal/permeability-increasing protein in patients with cystic fibrosis.
Zhao MH, Jayne DR, Ardiles LG, Culley F, Hodson ME, Lockwood CM
Department of Medicine, University of Cambridge, UK.
Cystic fibrosis (CF), a genetic disorder, is characterized by chronic pulmonary infection/inflammation which leads to respiratory failure. The presence of anti-neutrophil cytoplasmic autoantibodies (ANCA) has previously been observed in the sera of patients with CF. In view of the known relationship of ANCA with primary vasculitis and of their putative pathogenetic role in these disorders, we studied the presence, specificity and isotype of ANCA and their clinical associations in 66 adult CF patients. None of the 66 CF samples had autoantibodies to the major ANCA antigens, proteinase 3 or myeloperoxidase. However, 60/66 (91%) CF samples contained IgG, and 55/66 (83%) IgA, autoantibodies to bactericidal/permeability-increasing protein (BPI), a recently-characterized ANCA specificity. All the IgA anti-BPI-positive samples were also IgG anti-BPI-positive. The autoantibody specificity was confirmed by inhibition assay and immunoblotting of CF sera against a neutrophil granule preparation. Furthermore, in this cross-sectional study, anti-BPI levels were inversely correlated with the observed reductions in FEV1 and FVC (IgA anti-BPI & FEV1: r = -0.508, p < 0.0001), and both IgG and IgA anti-BPI levels were higher in CF patients with secondary vasculitis (n = 6) than in those without (p < 0.05). ANCA with specificity for BPI were present in the majority of CF sera in this study and autoimmune processes may be associated with the development of pulmonary injury in CF.
PMID: 8733512, UI: 96297562 |
