Functional characterization of antineutrophil cytoplasmic antibodies in patients with cocaine-induced midline destructive lesions.

OBJECTIVE: Antineutrophil cytoplasmic antibodies (ANCA) binding to neutrophil elastase (NE) and proteinase 3 (PR3) are detectable in most patients with cocaine-induced midline destructive lesions (CIMDL), but the pathogenic role and antigen specificity of these antibodies are unknown. This study was undertaken to assess the effects of NE ANCA on the enzymatic activity of NE, to determine whether these antibodies interfere with the physiologic effect of secretory leukoprotease inhibitor (SLPI), and to investigate the antigen specificity of both NE and PR3 ANCA in patients with CIMDL. We also compared the binding of PR3 ANCA in patients with CIMDL with that in patients with Wegener's granulomatosis (WG). METHODS: PR3 ANCA and NE ANCA were detected by capture enzyme-linked immunosorbent assays (ELISAs) and by indirect immunofluorescence. IgG was purified from the patients' sera, and the influence of NE ANCA on the enzymatic activity of NE and on the inhibitory activity of SLPI was investigated by determining the hydrolysis of N-methoxysuccinyl-Ala-Ala-Pro-Val p-nitroanilide by NE. RESULTS: IgG from NE ANCA-positive sera of patients with CIMDL inhibited the enzymatic activity of NE and did not interfere with the activity of SLPI. In contrast to the findings in WG sera, measurement of PR3 ANCA in CIMDL sera showed only fair to moderate concordance between the 2 different capture ELISAs. Cross-inhibition experiments demonstrated that NE ANCA and PR3 ANCA represent distinct autoantibodies in patients with CIMDL. CONCLUSION: The functional effects of NE ANCA on the enzymatic activity of NE or on the activity of SLPI cannot be implicated in the pathogenesis of CIMDL. The autoimmune reaction that targets neutrophil serine proteases in patients with CIMDL is frequently directed against more than one antigen. The ANCA response, including the reactivity of PR3 ANCA, in patients with CIMDL differs from what has been described in patients with WG.

B7-H3 ligand expression by prostate cancer: a novel marker of prognosis and potential target for therapy.

B7 coregulatory ligands can be aberrantly expressed in human disease. In the context of cancer, these ligands may act as antigen-specific inhibitors of T-cell-mediated antitumoral immunity. We recently reported that B7-H1 expression by carcinomas of the kidney and bladder portends aggressive disease and diminished survival. The expression of these proteins in prostate cancer, however, has not been investigated. We evaluated B7-H3 and B7-H1 protein expression in the pathologic specimens of 338 men treated for clinically localized prostate cancer between 1995 and 1998 with radical retropubic prostatectomy. Expression levels of B7-H3 in prostate cancer were correlated with pathologic indicators of aggressive cancer as well as clinical outcome. We report that B7-H3 is uniformly and aberrantly expressed by adenocarcinomas of the prostate, high-grade prostatic intraepithelial neoplasia, and four prostate cancer cell lines, whereas B7-H1 is rarely expressed. B7-H3 is expressed by benign prostatic epithelia, although at a more reduced level relative to neoplastic tissue. Increasing levels of B7-H3 intensity correlate with worsening clinicopathologic features of prostate cancer. Marked B7-H3 intensity, present in 67 (19.8%) specimens, confers a >4-fold increased risk of cancer progression after surgery (risk ratio, 4.42; P < 0.001). A survey of normal tissues revealed that B7-H3 is expressed within the liver, urothelium, and fetal kidney. In summary, B7-H3 is aberrantly expressed in all prostate cancers and represents an independent predictor of cancer progression following surgery. Moreover, B7-H3 encompasses a novel diagnostic and potential therapeutic target for the clinical management of prostate cancer and, perhaps, other malignancies as well.