Neutrophils, unopposed neutrophil elastase, and alpha1-antiprotease defenses following human lung transplantation.

Neutrophils are sequestered in the newly transplanted lung after reperfusion or with infection, rejection, and chronic graft dysfunction. Because unopposed (free) neutrophil elastase (NE) released into bronchoalveolar secretions may injure the lung allograft and impair bacterial clearance, we assessed total neutrophil numbers, myeloperoxidase activity as an index of neutrophil influx and degranulation, alpha1-antiprotease (alpha1-AP) concentrations, and unopposed NE activity in bronchoalveolar secretions from lung transplant recipients. Unopposed NE activity was present in bronchoalveolar lavage fluid (BALF) from recipients transplanted for emphysema associated with alpha1-AP deficiency as well as recipients without such deficiency (171 of 2,137 BALF; 8%). Ten of 17 (59%) recipients with alpha1-AP deficiency who were followed for at least 1 yr after transplant with multiple surveillance and diagnostic bronchoscopies had at least one BALF containing unopposed NE, usually associated with the presence of > or = 10(5) colony forming units/ml BALF of aerobic bacteria. In contrast, 19 of 58 (33%) with emphysema not associated with alpha1-AP deficiency, 8 of 32 (25%) recipients with cystic fibrosis (CF), 6 of 16 (38%) with idiopathic pulmonary fibrosis (IPF), and 11 of 36 (31%) with other indications for transplant had unopposed NE in BALF. alpha1-AP levels were significantly elevated in the early posttransplant time period and could be augmented considerably in alpha1-AP-deficient recipients with episodes of infection or rejection. Our findings indicate that unopposed NE activity can be found in both alpha1-AP-deficient and alpha1-AP-sufficient recipients after transplantation, usually in association with endobronchial bacterial infection.

Vascular endothelial growth factor in human lung transplantation.

STUDY OBJECTIVES: To determine levels of the vascular endothelial growth factor (VEGF) isoform consisting of 165 amino acids (VEGF(165)) in BAL fluid (BALF) from lung transplant recipients (LTXs). DESIGN: Bronchoscopy with BAL was performed on LTXs and normal volunteers (NVs). SETTING: University hospital. PARTICIPANTS: LTXs (n = 57) and NVs (n = 15). MEASUREMENTS AND RESULT: VEGF(165) concentrations in BALF were higher (mean +/- SEM, 240 +/- 32 pg/mL) for NVs (n = 15) vs 133 +/- 14 pg/mL for LTXs (n = 37) who were stable without evidence of significant rejection or infection at 6 months after transplantation (p < 0.0001). BALF VEGF concentrations sampled at 24 to 48 h, 2 weeks, 4 weeks, and 6 months after transplantation for 11 LTXs who lacked rejection or infection at any time point were 71 +/- 8 pg/mL, 80 +/- 20 pg/mL, 82 +/- 13 pg/mL, and 167 +/- 31 pg/mL, respectively. VEGF concentrations in BALF for LTXs with cytomegalovirus (CMV) pneumonia were 55 +/- 12 pg/mL (n = 10), 117 +/- 33 pg/mL for grade A3 acute rejection (n = 9), and 82 +/- 17 pg/mL (n = 14) for active bronchiolitis obliterans syndrome (BOS). Concentrations of VEGF in BALF at 6 months for the 32 stable recipients with bilateral lung transplantation were significantly higher for those with higher values for FEV(1), and BALF VEGF concentrations were significantly lower in BALF at 6 months for those recipients who subsequently went on to develop BOS (86 +/- 19 pg/mL) vs those who did not (158 +/- 18 pg/mL; p = 0.03). Serum concentrations of VEGF did not correlate with VEGF concentrations in BALF, but serum VEGF was 291 +/- 62 pg/mL at 10 to 14 days after transplantation vs 130 +/- 20 pg/mL at 4 weeks for nine LTXs with paired samples (p < 0.02). Serum VEGF concentrations for NVs (n = 15) were 102 +/- 15 pg/mL vs 94 +/- 17 for stable LTXs (n = 12) at 24 weeks after transplantation and 123 +/- 33 pg/mL for LTXs with active BOS (n = 10). CONCLUSIONS: BALF VEGF concentrations are particularly depressed at early time points following lung transplantation, gradually improve in the absence of significant rejection or infection, and are lower with active rejection or CMV pneumonia.

Short- and long-term results after lung volume reduction surgery.

Lung volume reduction surgery (LVRS) is a palliative surgical procedure for patients with severe emphysema. Resection of nonfunctional emphysematous lung tissue has been reported to relieve breathlessness and to improve quality of life for many patients by improving lung elastic recoil, respiratory muscle function, and ventilation-perfusion matching. However, the risks and benefits of LVRS remain controversial, as mainly short-term data are available for carefully selected groups of LVRS patients and no prospective, randomized trials for LVRS with pulmonary rehabilitation versus optimal medical therapy plus pulmonary rehabilitation have been reported. Bilateral staple resection for LVRS appears to be superior to use of a laser or unilateral approach in the short term, but relatively little data exist on long-term outcomes. Additional clinical investigation is required to determine whether LVRS should be a widely accepted therapy for severe emphysema.

Soluble donor HLA class I and beta 2m-free heavy chain in serum of lung transplant recipients: steady-state levels and increases in patients with recurrent CMV infection, acute rejection episodes, and poor outcome.

We determined the concentration of donor sHLA/beta(2)m and total beta(2)m-free heavy chain (HC) in the serum of lung transplant recipients with ELISA assays. While we were unable to detect specific donor beta(2)m-free HCs due to a lack of available antibodies, we could determine if events that led to an increase in the release of beta(2)m-free HC also led to an increase in the release of donor sHLA/beta(2)m, particularly the 36 kDa, proteolytically cleaved form. We found that lung transplants constituitively release donor sHLA/beta(2)m at ng/ml levels. The levels (both of donor sHLA/beta(2)m and total beta(2)m-free HC) were significantly increased in CMV-sero-negative recipients (but not in CMV-sero-positive recipients) at the onset of post-transplant CMV disease. Acute rejection episodes were also associated with an increased release of donor sHLA/beta(2)m, but not of beta(2)m-free HC. However, in patients with particularly poor outcome (i.e., graft loss within 1 year) there was a significant release of beta(2)m-free HC. Analysis of one such patient showed a predominance of 36 kDa forms of donor-sHLA/beta(2)m. Our data are consistent with the hypothesis that the metalloproteinase that cleaves beta(2)m-free HC is active during uncontrolled CMV infection and acute rejection. However, recall responses to CMV and controlled immune responses to donor may result in little or no activation of sHLA class I release.

Soluble HLA class I in epithelial lining fluid of lung transplants: associations with graft outcome.

We hypothesized that the small amounts of donor HLA-A and HLA-B proteins detected in the serum during organ allograft rejection are indicative of higher local releases within the graft itself. We determined the concentrations of total HLA class I (HLA-I) and, in selected cases, specific donor and host HLA-A and HLA-B proteins, in the epithelial lining fluid (ELF) sampled by bronchoalveolar lavage (BAL) of lung transplant recipients (n = 37) and of normal controls (n = 25). We found that 1) HLA-I proteins were enriched in the lung ELF relative to other proteins; 2) the concentration of HLA-I in the ELF of well-functioning transplants was similar to that in normal lungs; 3) HLA-I proteins and total proteins were elevated in the ELF of patients who developed chronic rejection or refractory acute rejection; 4) the concentration of HLA-I was correlated with the percentage of neutrophils but not with the percentage of lymphocytes in the ELF of transplanted lungs; and 5) only the percentage of lymphocytes was elevated in the ELF of transplant patients with active CMV infections. Total HLA-I from the ELF was found to contain a mixture of both donor- and recipient-type HLA-A and HLA-B proteins and the donor-type HLA-A2 was found to be highly enriched in the ELF relative to serum.

Description of the leukocyte function-associated antigen 1 (LFA-1 or CD11a) promoter.

The CD11a/CD18 (leukocyte function-associated antigen 1 or LFA-1) leukocyte integrin is expressed at high levels on the cell surface of T lymphocytes and macrophages, where it mediates homotypic and heterotypic adherence between leukocytes and other cell types by binding to intracellular adhesion molecules 1 and 2 on the conjugate cell. To initiate studies of the molecular regulation of expression of the CD11a molecule, we isolated genomic clones corresponding to the 5'-flanking region of CD11a, identified the transcriptional start sites for CD11a, and characterized the CD11a promoter sequence in transient expression assays. The CD11a promoter (1.7 kb) directed functional activity of a heterologous reporter gene in the T-lymphocyte cell line Jurkat and the myeloid cell line HL-60 but did not direct functional activity in three different nonleukocyte cell lines. Deletional analysis of the CD11a promoter sequence indicated the presence of distinct, cell-type-specific regulatory sequences with the region from -40 to -17 relative to the transcription start sites responsible for most of the in vitro activity of the CD11a promoter in the Jurkat T-cell line, and the promoter sequence located within the first 17 bp relative to the transcription start sites responsible for CD11a promoter activity in the HL-60 cell line. Identification of the CD11a promoter provides the opportunity to identify unique cis-acting elements and trans-acting factors responsible for the cell-type-specific expression of CD11a in human leukocytes. Further, the CD11a promoter may be useful in transgenic constructs and in retroviral vectors to direct expression of heterologous genes selectively in leukocytes.