Post-transplant obliterative bronchiolitis and other late lung sequelae in human heart-lung transplantation

Acute and chronic onset of bronchiolitis obliterans syndrome (BOS): are they different entities?

BACKGROUND

Bronchiolitis obliterans syndrome (BOS), defined as an irreversible, staged decline in forced expiratory volume in 1 second (FEV(1)), is an established marker of obliterative bronchiolitis. Potential causes of BOS include sub-clinical chronic rejection and/or exaggerated healing response following acute injury. BOS may thus result from two or more distinct processes, both acute and chronic.

METHODS

A total of 5,916 measurements of FEV(1) from 204 lung transplant recipients surviving at least 6 months after transplantation were analyzed. Follow-up ranged from 6 months to 13 years. By adjusting for the acute effects of rejection, pulmonary infection and measurement variation on FEV(1) trace, patients either had a linear decline characterized by a single acute drop in FEV(1) of >15% at BOS onset, or a chronic linear decline in FEV(1). The fraction having acute onset was estimated. Acute events occurring within the first 6 months were assessed as risk factors for acute onset BOS.

RESULTS

Of the 204 patients, 8% died before BOS onset and 18% were BOS-free at analysis. For 18% of patients, BOS onset followed a chronic linear decline in FEV(1) of 3.7% per year, with a median time of BOS onset >99 months. For 56% of patients, BOS onset followed an acute drop in FEV(1) of median 33.8% (95% CI 19.1% to 39.7%), with median onset time of 52 months. During the first 6 months, acute rejection was significantly and independently associated with acute onset of BOS (relative risk = 1.15 per episode, 95% CI [1.03 to 1.29], p = 0.01), whereas pulmonary infection and cytomegalovirus (CMV) infection were not. Acute BOS onset followed a documented acute event in the previous 6 months in 38 of 114 (33%) of cases.

CONCLUSIONS

BOS likely reflects more than one process. Compared with those who had a slow linear decline in lung function, acute BOS onset was associated with acute rejection in the first 6 months, was often triggered by an acute event and had poor prognosis, with obliterative bronchiolitis (OB) the main cause of death.

Decreased serum and bronchoalveolar lavage levels of Clara cell secretory protein (CC16) is associated with bronchiolitis obliterans syndrome and airway neutrophilia in lung transplant recipients

BACKGROUND

The major hinderance for long-term survival after lung transplantation is chronic rejection in the form of bronchiolitis obliterans syndrome (BOS). BOS is a fibrosing process in the small airways causing irreversible airway obstruction. BOS is associated with increased oxidative burden and activation of inflammatory and growth-stimulating mediators. The Clara cell secretory protein (CCSP or CC16) is a secreted differentiation marker for the bronchiolar epithelium with both antioxidative and antiinflammatory/immmunomodulatory properties. We asked whether this molecule could have a role in the development of BOS.

METHODS

Serum and bronchoalveolar lavage (BAL) fluid samples were collected from 22 consecutive lung transplant recipients, the majority (19) was followed for 2 years. Six patients developed BOS. CCSP in serum was measured in 162 samples from 19 patients with an ELISA method, and CCSP in 191 BAL samples from 22 patients with quantitative Western blot.

RESULTS

CCSP in both serum and BAL was significantly lower in BOS compared with acute rejection or no rejection. After the first postoperative month, serum and BAL CCSP levels were consistently lower in the patients who developed BOS than in those who did not. The percentage of neutrophils in BAL correlated negatively with CCSP in BAL.

CONCLUSIONS

Levels of CCSP in serum and BAL is lowered in BOS. Serum CCSP could have a potential as an early marker for BOS. The correlation between decreased CCSP and increased neutrophils in BAL suggests a loss of local airway defense capacity in BOS.

A comparison of rat tracheal transplant models: implantation verses anastomotic techniques for the study of airway rejection

BACKGROUND

In rodent models, investigators have transplanted donor tracheas into a recipient rat's abdomen or s.c. tissue to study airway rejection. We describe a modification of this model, which provides improved histology to study the airway injury related to obliterative bronchiolitis.

METHODS

The standard technique of implanting the donor trachea was compared to a model in which a tracheal Y graft was created by anastomosis of the donor trachea to the recipient airway. Syngeneic and allogeneic tracheal grafts (Lewis and Brown Norway rats) were harvested at 2 and 4 weeks using each model (eight groups).

RESULTS

Gross patency at the tracheal anastomosis grafts was 100%. All donor tracheas, which were implanted without an anastomosis, were occluded with mucus (syngeneic) or granulation tissue (allogeneic). Syngeneic implant grafts demonstrated significantly less lumenal granulation tissue 35.3%+/-32 than the allograft implant group (95.3%+/-9.2, P=0.0005 at 4 weeks). The anastomotic allograft group demonstrated significantly less lumenal granulation tissue 48.3%+/-23.7 when compared with the implanted allograft group (P=0.003). The implanted allograft demonstrated a severe loss of epithelial integrity by 2 weeks (16.7%+/-38), which progressed to complete loss by 4 weeks (P=0.0001 and P=0.0001 vs. native). This loss was significantly more than that of the anastomotic group at 2 weeks (89.5%+/-13, P=0.004) and 4 weeks (88.3+/-29, P=0.005).

CONCLUSIONS

The rat tracheal allograft anastomosed to the recipient airway demonstrated less lumenal granulation tissue obstruction and better preservation of epithelial integrity than an implant allograft, suggesting that an open airway improves assessment of transplant-related changes associated with rejection.

Risk factors for bronchiolitis obliterans: a systematic review of recent publications

BACKGROUND

Obliterative bronchiolitis remains the major limitation to long-term survival after lung transplantation. A thorough understanding of the factors that confer high risk of developing obliterative bronchiolitis or its physiologic surrogate bronchiolitis obliterans syndrome is important to help define therapeutic strategies.

METHODS

We performed a systematic review of studies published since the beginning of 1990. The review excluded non-human studies, publications before 1990, small (less than 25 patients) studies that were predominantly concerned with investigating the pathogenesis of obliterative bronchiolitis, studies solely concerned with diagnosis or treatment of obliterative bronchiolitis, and overlapping studies from the same center. Onset of bronchiolitis obliterans syndrome or obliterative bronchiolitis was the outcome of interest.

RESULTS

Acute rejection plays an important role in obliterative bronchiolitis and bronchiolitis obliterans syndrome onset, and late rejection is a significant risk factor. Lymphocytic bronchitis/bronchiolitis is also a risk factor, with some evidence that late onset is associated with greater risk. The effects of cytomegalovirus, other infectious organisms, and human leukocyte antigen matching are less clear and require further confirmation. There is little evidence that recipient and donor characteristics play a major role.

CONCLUSIONS

This systematic review supports the view that obliterative bronchiolitis arises from alloimmunologic injury marked by clinically apparent acute rejection episodes and that inflammatory conditions, including viral infections or ischemic injury, may also play a role. Implications for therapy are discussed.

Dependence of murine obstructive airway disease on CD40 ligand

BACKGROUND

Human lung transplantation carries a poor prognosis because of chronic rejection in the form of obliterative bronchiolitis syndrome (OBS). Using the mouse model of heterotopic tracheal transplantation, we examined the role of costimulation in the allograft rejection that characterizes obstructive airway disease (OAD).

METHODS

C57BL/6 or BALB/c tracheae were implanted into wild-type control, CD28-/-, muMT (B-cell deficient), or CD40L-/- recipient mice. Grafts were explanted from 7 to 42 days posttransplantation and evaluated.

RESULTS

Thickening of the basement membrane and a decrease in patent luminal area were first noted at 2 weeks in wild-type allogeneic trachea recipients and to a slightly lesser degree in CD28-/- recipients. In contrast, CD40L-/- recipient mice showed no evidence of cellular infiltrates or fibrosis in transplanted tracheae. To determine whether CD40L interacted with host or donor CD40, CD40-deficient tracheae were transplanted into CD40L+/+, CD40+/+ wild-type mice. Wild-type mice rejected CD40-/- tracheae. Tracheae were transplanted into B-cell-deficient mice to determine the role of B-cell CD40 in chronic pulmonary allograft rejection. The OAD reaction was identical in wild-type and B-cell-deficient mice.

CONCLUSIONS

Development of OAD in the mouse trachea transplant model is primarily dependent on CD40L and is relatively CD28 independent. The ability of mice to reject CD40-/- tracheae demonstrated that host, not donor, CD40 is required for rejection. Furthermore, the ability of B-cell-deficient mice to reject allogeneic tracheae demonstrated that B-cell CD40-mediated responses are not required for the development of OAD.

Susceptibility to cytomegalovirus infection may be dependent on the cytokine response to the virus

BACKGROUND

Cytomegalovirus (CMV) infection is an important cause of morbidity and mortality in an immunocompromised host. Pulmonary infection with CMV results in an inflammatory response, which includes the local production of cytokines. Cytokine production stimulated by CMV infection serves to activate a series of immunologic responses involved in viral clearance. Previous work has demonstrated that different mouse strains express variable sensitivity to CMV infection.

METHODS

Using mouse strains that express sensitive (BALB/cj) and resistant (C57BL/6) CMV phenotypes, we asked whether the differences in susceptibility to infection were caused by differences in pulmonary cytokine production after intraperitoneal infection with CMV.

RESULTS

C57 mice demonstrated a higher total bronchoalveolar lavage (BAL) and BAL lymphocyte count at 3 and 7 days after intraperitoneal infection compared with BALB mice. There were no differences in BAL cytokine production; however, we were able to demonstrate differences in CMV DNA load in the lungs of BALB mice compared with that of C57 mice. In addition, there appeared to be increased whole-lung production of the TH2 cytokine IL-10 in the BALB mice versus the C57 mice.

CONCLUSIONS

This observation suggests that the genetic susceptibility to CMV infection may, in part, be regulated by differences in cytokines production within the local environment.

Pleural-changes in the lung allograft during acute rejection

To ascertain the cause of pleural fibrosis in lung allografts, pleural changes were investigated in rat syngeneic and allogeneic lung grafts. The pleura of lung syngeneic grafts showed no pathological changes except for mild edema on the first day after transplantation. In lung allografts, recipient cells migrated into the subpleural tissue early after transplantation (latent phase). In the vascuar phase, recipient lymphocytes in the subpleural tissue increased in number, while almost all alveolar structures were free from infiltration. Both CD4-positive and CD8-positive cells infiltrated in almost equal numbers with macrophages. The subsets of infiltrating cells were similar to those of the perivascular and peribronchial areas. In the late vascular or alveolar phase, fibroblasts were observed among the infiltrating cells, and fibrotic changes started. In the destructive phase, collagen formation with marked pleural thickening was dominant. Pulmonary acute rejection should be treated at least up to the late vascular phase to prevent pleural fibrosis.

Early lung leukocyte infiltration, HLA and adhesion molecule expression predict chronic rejection

Obliterative bronchiolitis remains the main cause of graft dysfunction and death after 1 year. Defined by an irreversible airway obstruction, bronchiolitis obliterans syndrome is usually recognized in the advanced stage of the disease, with histological evidence of fibrotic damage. Fibrosis represents the end-stage of an inflammatory process, leading to the postulate that chronic lung graft dysfunction is preceded by cellular and molecular events. This study was performed during the first year following lung transplantation, in the absence of histological or functional criteria of chronic rejection. Transbronchial biopsies from eight lung allografts were examined. Four developed a bronchiolitis obliterans syndrome (Group I), and 4 had good outcomes (Group II) at 2 years. Using immunohistochemistry, the aim of the study was to correlate early immunological events with graft outcomes at 2 years. An up-regulation of HLA class I antigen (P = 0.0001), an overexpression of Ki-67 (P = 0.006) on bronchial epithelium, and graft infiltration by CD45+, CD25+ cells (P = 0.003) were significantly associated with the development of chronic rejection. An overexpression of numerous adhesion molecules was observed. However, only very late antigen-4 had a discriminative value (P = 0.04), preceding chronic graft dysfunction. Our results suggest that graft dysfunction is associated with early molecular and cellular events, and raises the possibility that a fibroproliferative disorder is initiated shortly after transplantation. The recognition of such early immunological markers might facilitate improved graft management and prognosis.

The heterotopic tracheal allograft as an animal model of obliterative bronchiolitis

Heterotopic tracheal allografts in small rodents have been shown to share many characteristics with the development of obliterative bronchiolitis (OB) in the clinic and therefore provide a suitable animal model for the study of OB. The model facilitates the examination of the pathogenesis of the disease and the elucidation of the cellular and molecular mechanisms involved in its development. The model provides a less technically demanding alternative to whole lung transplantation in small rodents and should lead to a speedier identification of new treatments that might prevent the development of post-transplantation OB in the clinic.

Bronchiolitis obliterans syndrome and additional costs of lung transplantation

STUDY OBJECTIVES

The influence of bronchiolitis obliterans syndrome (BOS) on costs after lung transplantation was investigated by comparing the costs of patients with and without this condition.

DESIGN

Follow-up costs were prospectively investigated in a medical technology assessment of the Dutch Lung Transplant Program, in relation to the development of the BOS. First, average follow-up costs per week per patient were compared between patients who did or did not develop BOS. Second, in the BOS group, these costs were compared before and after the onset of BOS.

SETTING

Dutch Lung Transplant Program, University Hospital of Groningen.

RESULTS

Data on 53 patients (37 patients without BOS and 16 with BOS) who underwent transplantation between November 1990 and April 1995 were available. The average follow-up time of these 53 patients was 1.5 years. The follow-up costs amounted to an average (in Dutch guilders [Dfl]) of 1,774/wk for non-BOS patients, compared to 3,072/wk for BOS patients (+ 73%; p = 0.002; one Dfl = 50 cents US currency). This difference in costs was largely accounted for by an increase in used health-care resources, in particular hospitalization and medication. For the BOS patients, the average costs per week before and after the onset of BOS were 1,941 Dfl and 2,422 Dfl, respectively.

CONCLUSION

BOS is associated with substantial extra costs. These findings reemphasize the need to focus efforts on prevention of BOS to enhance the cost-effectiveness of lung transplantation.

Donor and recipient leukocytes in organ allografts of recipients with variable donor-specific tolerance: with particular reference to chronic rejection

We have attributed organ engraftment to clonal exhaustion-deletion of host-versus-graft and graft-versus-host reactions that are reciprocally induced and governed by migratory donor and recipient leukocytes. The so-called donor passenger leukocytes that migrate from the allograft into the recipients have been thoroughly studied (chimerism), but not the donor leukocytes that remain in, or return to, the transplanted organ. Therefore, using flow cytometry we determined the percentage and lineages of donor leukocytes in cell suspensions prepared from Lewis (LEW) cardiac allografts to 100 days posttransplantation. The LEW hearts were transplanted to naïve untreated Brown Norway (BN) recipients (group 2), to naïve BN recipients treated with a 28-day or continuous course of tacrolimus (TAC) (groups 3 and 4), and to drug-free BN recipients pretolerized by earlier bone marrow cell (BMC) or orthotopic LEW liver transplantation (groups 5 and 6). The findings in the heart cell suspensions were correlated with the results from parallel histopathologic-immunocytochemical studies and other studies of the grafts and of host tissues. Although the LEW heart allografts were rejected in 9.6 days by the unmodified recipients of group 2, all beat for 100 days in the recipients of groups 3 through 6. Nevertheless, all of the long-surviving cardiac allografts (but not the isografts in group 1) were the targets of an immune reaction at 5 days, reflected by dramatic increases in the ratio of leukocytes to nonleukocyte nucleated cells from normal values of 1:5-1:6 to 1:1-5:1 and by manifold other evidence of a major inflammatory event. The acute changes returned to baseline by 100 days in the chronic rejection (CR) free hearts of groups 4 and 6, but not in the CR-afflicted hearts of short-course TAC group 3 or the less-severely damaged hearts of the BMC-prime group 5. The freedom from CR in groups 4 and 6 was associated with a large donor contribution to the intracardiac leukocyte population at 5 days (28.6% and 22% in the respective groups) and at 100 days (30.5% in group 4 and 8.4% in group 6) compared with 2% and 1.2% at 100 days in the CR-blighted allografts of the partially tolerant animals of groups 3 and 5. Whether large or small, the donor leukocyte fraction always included a subset of class II leukocytes that had histopathologic features of dendritic cells. These class II(+) cells were of mixed myeloid (CD11b/c(+)) and lymphoid lineages; their migration was markedly inhibited by TAC and accelerated by donor-specific priming and TAC discontinuance. Although a large donor leukocyte population and a normal leukocyte/nonleukocyte cell ratio were associated with freedom from CR, these findings and the lineage profile of the intracardiac leukocytes were not associated with tolerance in the animals of groups 3 and 4 under active TAC treatment. The findings in this study, singly and in their entirety, are compatible with our previously proposed leukocyte migration-localization paradigm of organ allograft acceptance and tolerance.

Immunosuppressive therapies for the prevention and treatment of obliterative airway disease in heterotopic rat trachea allografts

BACKGROUND

Obliterative bronchiolitis remains a major long-term complication after lung transplantation. Using a reproducible model of heterotopically transplanted rat tracheas, this study examined the role of several novel immunosuppresive compounds to prevent and reverse obliterative airway disease in these animals.

METHODS

Brown Norway rat trachea were transplanted into the greater omentum of Lewis (allografts) or Brown Norway (isografts) animals. Recipient animals were treated with rapamycin, cyclosporine, 15-deoxyspergulin, mycophenolate mofetil, or leflunomide from day 0, 7, or 14 until day of graft removal, either day 28 or 50. Trachea segments were evaluated for degree of lumenal occlusion, as well as percent and type of lumen epithelial cell coverage.

RESULTS

All untreated allografted tracheas obliterated completely, although isografts appeared patent with normal respiratory epithelium when they were removed. Leflunomide, rapamycin, and cyclosporine effectively prevented obliteration when treatment was initiated at day 0, with rapamycin showing continued efficacy when initiated as late as day 7. 15-deoxyspergulin and mycophenolate mofetil failed to consistently inhibit obliteration with any treatment schedule. An inverse correlation was found between epithelial coverage and degree of obliteration, and was especially pronounced in grafts from cyclosporine-treated animals.

CONCLUSIONS

Immunosuppressive drug therapy will inhibit airway obliteration, but efficacy sharply diminishes if initiation of treatment is delayed. Efficacy also varies among immunosuppressive compounds, and results indicate those drugs that enable epithelial regrowth most effectively inhibit airway graft obliteration.

Bronchiolitis obliterans syndrome after lung transplantation and health-related quality of life

The present study was undertaken to assess the relationship between health-related quality of life (HRQOL) and bronchiolitis obliterans syndrome (BOS), as both represent important parameters of outcome after lung transplantation. HRQOL was measured both cross-sectionally and longitudinally by standardized patient self-administered questionnaires, including the Nottingham Health Profile, the State-trait Anxiety Inventory, the Zung Self-Rating Depression Scale, and the Index of Well-Being. Data were collected at 4 and 7 mo, and every 6 mo afterwards for as long as 49 mo post-transplantation. The number of patients who completed the questionnaires varied from 72 at 4 mo, to 27 at 49 mo after transplantation. Cross-sectionally, the patients with BOS reported persistently statistically significantly more restrictions on the dimensions energy and physical mobility of the Nottingham Health Profile compared with patients without BOS. Other domains, i.e., pain, sleep, social interaction, and emotional reactions, were not affected. Additionally, patients with BOS reported statistically significantly more depressive symptoms and anxiety 1 and 2 yr after transplantation. Results from the longitudinal analysis support these findings, although no change in depressive symptoms could be found after onset of BOS. This study suggests that all lung transplant recipients improve in HRQOL. The development of BOS, however, is associated with a significantly reduced HRQOL.

Pulmonary complications following lung transplantation

Lung transplantation has become an accepted procedure for the treatment of end-stage lung disease, being successful in improving the quality and length of life of many patients. The recognition and early treatment of complications is important for long-term survival of lung transplant recipients. The radiologist frequently plays a central role in investigation. The radiological appearance of pulmonary complications arising in the immediate, early (within 2 months) and late (after 2 months) stages post-transplantation are reviewed.

Dendritic cells and macrophages in lung allografts: A role in chronic rejection?

Antigen presentation by lung macrophages/dendritic cells (DC) is thought to be important in obliterative bronchiolitis/bronchiolitis obliterans syndrome (OB/BOS), which severely limits survival post-lung transplantation. However, a recent study found minimal numbers of DC in lung allografts. We looked at numbers and phenotype of macrophages/DC in lung allografts using endobronchial biopsy (EBB) and transbronchial biopsy (TBB) from 22 lung transplant patients. Biopsies were stained with monoclonal markers of DC (CD1a, RFD1, and major histocompatibility complex [MHC] Class II), and "suppressor macrophages" (RFD1 and RFD7). Dendritic cells were also stained for the costimulatory molecules CD80 and CD86. Significantly greater numbers of DC/high-power field (HPF) were seen in biopsies when we defined DC using dendritic morphology and Class II MHC expression instead of CD1a expression. Dendritic cell numbers were significantly higher in eight patients with OB/BOS compared with 14 stable patients. Fifty percent of DC expressed CD86 and 20% expressed CD80. There was no difference in CD80 or CD86 expression between OB/BOS patients and stable patients. There was no correlation between DC numbers and presence or absence of acute rejection (AR), and/or cytomegalovirus (CMV) pneumonitis on current or prior biopsies. There were significantly more MHC Class II DC in EBB compared with TBB. We found minimal staining for lung macrophages capable of suppressing T-cell inflammation. We conclude that studies of lung allografts may underestimate DC numbers if relying on CD1a as the sole marker of DC. DC are increased in patients with OB/BOS compared with stable patients. EBB may be more important than TBB in looking for inflammatory changes of OB. DC expressing costimulatory molecules are present in lung allografts, and costimulatory pathway blockade may be useful in human lung allografts. Also, the absence of "suppressor" macrophages may increase susceptibility of human lung allografts to the rejection process.

Obliterative bronchiolitis after lung transplantation

Despite marked improvements in early survival, long-term outcome after lung transplantation is still threatened by obliterative bronchiolitis (OB). Thought to be a manifestation of chronic allograft rejection, OB affects up to 65% of patients at 5 years after surgery and produces a relentless airflow obstruction. Early and late acute rejection are the primary risk factors for OB, but cytomegalovirus infection and airway ischemia may also play a role. In most patients, OB responds poorly to augmented immunosuppression and eventually leads to infectious complications and terminal respiratory failure. Because early diagnosis is associated with better prognosis, every effort should be made to detect OB in a preclinical stage. This may be best achieved by combining several techniques, such as surveillance transbronchial biopsy and bronchoalveolar lavage, measurements of ventilation distribution and exhaled nitric oxide, and expiratory computed tomography.

Mycoplasma pneumoniae-associated bronchiolitis causing severe restrictive lung disease in adults: report of three cases and literature review

STUDY OBJECTIVES

To characterize adult Mycoplasma pneumoniae-induced bronchiolitis requiring hospitalization.

DESIGN

We encountered an adult patient with severe bronchiolitis in the absence of pneumonia due to M. pneumoniae. To determine the relative frequency of such a condition, we retrospectively reviewed the medical records of adults over a 4-year period with a hospital discharge diagnosis of "bronchiolitis" from a university hospital.

SETTING

University Hospital of the University of Colorado Health Sciences Center, Denver, CO.

STUDY SUBJECTS

From 1994 to 1998, 10 adult inpatients were identified with a diagnosis of bronchiolitis. There were two with respiratory bronchiolitis, one with panbronchiolitis, one patient with bronchiolitis obliterans organizing pneumonia (BOOP), and six with acute inflammatory bronchiolitis. Including the initial patient, three had a definitive clinical diagnosis of Mycoplasma-associated bronchiolitis.

RESULTS

The three adult patients with bronchiolitis due to M. pneumoniae are unusual because they occurred in the absence of radiographic features of a lobar or patchy alveolar pneumonia. Hospital admission was occasioned by the severity of symptoms and gas exchange abnormalities. One patient had bronchiolitis as well as organizing pneumonia (BOOP) that responded favorably to corticosteroid treatment. The other two had high-resolution CT findings diagnostic of an acute inflammatory bronchiolitis. One of the patients with inflammatory bronchiolitis had an unusual pattern of marked ventilation and perfusion defects localized predominantly to the left lung. All three had restrictive ventilatory impairment on physiologic testing.

CONCLUSIONS

In adults, Mycoplasma-associated bronchiolitis without pneumonia is rarely reported, but in hospitalized patients, it may be more common than expected and may be associated with severe physiologic disturbances.

Altered lung mechanics after double-lung transplantation

We studied lung mechanics and small airways function in 15 patients after double-lung (DL) transplantation. Patients were classified as stable (DL-S, n = 11), or having obliterative bronchiolitis syndrome (DL-OBS, n = 4). We performed pulmonary function tests (PFT), measured slope of phase 3 of the single-breath nitrogen test (N2SP3), and obtained pressure-volume curves and values: chord compliance (Cst,L), specific chord compliance (SCst,L), and elastic recoil pressure at 90% TLC. PFT showed mild restrictive pattern in DL-S and severe obstructive lung disease in DL-OBS. The N2SP3 measurement indicated small airways dysfunction in 82% of DL-S and in all DL-OBS patients. The Cst,L was 0.24 +/- 0.08 L/cm H2O in DL-S and 0.16 +/- 0.05 L/cm H2O in DL-OBS, both lower than control subjects 0.34 +/- 0. 09 L/cm H2O (p < 0.01; p < 0.001). Moreover, SCst,L was 0.09 +/- 0. 03 cm H2O-1 in DL-S, and 0.05 +/- 0.02 cm H2O-1 in DL-OBS, significantly lower than control subjects 0.12 +/- 0.02 cm H2O-1 (p < 0.05; p < 0.001). Elastic recoil at 90% TLC was normal in 14 of 15 patients. We found a linear correlation between N2SP3 and FEV1, and between FEV1 and Cst,L and SCst,L for combined DL-S and DL-OBS. Reduced compliance near FRC with normal elastic recoil at high lung volumes does not suggest changes in lung parenchyma. We speculate that structural or functional alterations in small airways may have contributed to low compliance measurements. Of special concern are our findings that DL-S had significant small airways dysfunction and reduced compliance in a pattern similar to the DL-OBS, only smaller in magnitude.

Constrictive (obliterative) bronchiolitis: diagnosis, etiology, and a critical review of the literature

Constrictive bronchiolitis (CB) (or obliterative bronchiolitis) designates inflammation and fibrosis occurring predominantly in the walls and contiguous tissues of membranous and respiratory bronchioles, with resultant narrowing of their lumens. It differs from bronchiolitis obliterans-organizing pneumonia in its histopathology and clinical course. Most cases of CB occur in the setting of organ transplants, particularly lung and heart-lung transplants, but also in bone marrow transplants. Other bona fide cases are rare: infection, particularly viral infection, appears to be a well-documented precursor to CB in children, but not in immunocompetent adults. Constrictive bronchiolitis also has been reported in the course of rheumatoid arthritis, in certain other autoimmune diseases such as pemphigus vulgaris, after inhalation of toxic gases such as nitrogen oxide, after ingestion of certain drugs or medicinal agents such as Sauropus androgynous, and as a cryptogenic illness. Recent reports suggest that CB, as defined by clinical criteria (that is, bronchiolitis obliterans syndrome), is very common in lung allograft recipients who survive more than 5 years and, although it is associated with significant mortality, it also can be clinically stable. Furthermore, with the current practice of close monitoring of these patients, it appears that CB may now be diagnosed at an earlier stage, at which resolution, or at least stabilization of progression, is possible. A histopathologic diagnosis of CB in lung transplant and other patients may be difficult to make due to the patchy distribution of lesions, the technical difficulty in obtaining tissue in late lesions with extensive fibrosis, and the failure to recognize lesions. With regard to the last of these, in early stages of disease, CB may be subtle and easily missed in routine hematoxylin-eosin-stained specimens, while in advanced stages the disease may be equally difficult to diagnose if the patchy scarring in the lung is interpreted as nonspecific. The relative loss of bronchioles and the relationship of the scars to contiguous arteries should signal the need for elastic stains to look for the residual elastica of the bronchioles amidst the foci of fibrosis. Increasingly, clinical grounds, including pulmonary functions studies and high-resolution computed tomography findings, are proving to be relatively sensitive methods of detecting CB. Finally, the progressive airway destruction in chronic transplantation rejection appears to be a T-cell-mediated process. The "active" form of constrictive bronchiolitis, with attendant lymphocytic inflammation of the airways, likely precedes the "inactive" or scarred form of constrictive bronchiolitis.

Bronchiolitis obliterans

Hospital survival rates in experienced lung transplantation centers exceed 90%, but late survival for lung allograft recipients is clouded by bronchiolitis obliterans syndrome (BOS). Bronchiolitis obliterans is the characteristic pathological feature of this late syndrome of chronic lung allograft dysfunction, which is thought to represent chronic lung allograft rejection. BOS seems to affect all lung transplant recipients, including single, bilateral, and heart-lung transplantation patients. Although specific symptoms are lacking, patients typically experience worsening respiratory debilitation, with the characteristic physiological hallmark being airflow limitation, as evidenced by progressive decline in several spirometric parameters. Because the clinical and functional aspects of this syndrome are not always coexistent with the typical pathology, a staging and classification system was devised that allows for diagnosis of BOS even in the absence of bronchiolitis obliterans. Data from Stanford University, featuring very prolonged follow-up, have shown that actuarial freedom from OB is only 29% at 5 years post lung transplantation. Overwhelming experimental evidence suggest that OB is the result of an immune-mediated process, and therefore the usual treatment for this condition has been to increase the maintenance immunosuppression regimen, and to further augment immunosuppression using a variety of strategies. Most of these strategies have been effective in achieving some reduction in the rate of decline in graft function, although true "cure" of BOS has been rare. Re-transplantation has been the most aggressive therapeutic strategy for OB, but for a number of logistic reasons, is applicable for only a tiny minority of lung transplant recipients with OB.

Pulmonary disease models induced by in vivo hemagglutinating virus of Japan liposome-mediated endothelin-1 gene transfer

Overproduction and overexpression of endothelin-1 (ET-1) have been reported to contribute to the pathophysiology of pulmonary diseases, including pulmonary fibrosis, obliterative bronchiolitis, and primary pulmonary hypertension. To determine whether ET-1 contributes to the pathogenesis of pulmonary disease, we locally overexpressed ET-1 using an in vivo UV-inactivated hemagglutinating virus of Japan (HVJ) liposome-mediated gene transfer system. Plasmid DNA of ET-1 (pME18fc preproET-1) and high mobility group 1 (HMG1) protein were co-encapsulated in liposomes. Then the plasmid DNA and liposome complexes were introduced into the lung via the trachea in Wistar rats, using HVJ-mediated membrane fusion. Control animals received instillation of HVJ liposome with an empty cassette. Two weeks after in vivo transfection of the preproET-1 gene, hyperplastic connective tissue plaques were seen in the alveolar duct and small conducting airways, indicating histologically distinctive obliterative bronchiolitis. No histopathologic changes were seen in the control animals. These results suggested that local overexpression of ET-1 may play an important role in the pathogenesis of obliterative bronchiolitis.

Bronchiolitis obliterans: pathogenesis, prevention, and management

Increasing early success-post lung transplant has been tempered by the long-term development of histologic bronchiolitis obliterans (OB) or of the progressive airway obstruction which is called bronchiolitis obliterans syndrome (BOS). Multiple lines of evidence suggest that OB/BOS is due to an injury directed against the epithelial cells in the airways of the donor lung by the immune system of the recipient. Acute rejection is the strongest risk factor for the subsequent development of this process. Efforts to prevent or minimize acute rejection may reduce the prevalence of OB/BOS. Results of treatment with augmented immunosuppression have been disappointing but the treatment of complicating infections in the allograft can be beneficial. Multicenter studies are needed to assess the efficacy of new immunosuppressive agents in preventing or treating OB/BOS.

Adenovirus-mediated interleukin-10 gene transfer inhibits post-transplant fibrous airway obliteration in an animal model of bronchiolitis obliterans

Bronchiolitis obliterans, a form of chronic allograft rejection characterized by progressive fibrous obliteration of the airways, is the major obstacle limiting prolonged survival of lung transplant recipients. To date, no effective therapy against this fatal complication exists. Interleukin-10 (IL-10), an anti-inflammatory and immunosuppressive cytokine, inhibits various T cell and antigen-presenting cell functions. We examined the effect of IL-10 in an animal model for bronchiolitis obliterans. A heterotopic tracheal transplant model was used. IL-10 was administered to the recipient either in its recombinant form by osmotic minipump or by adenoviral-mediated IL-10 gene transfer (Ad5E1mIL-10). Successful gene transfection and expression was confirmed by measuring circulating IL-10 protein. Tracheal allografts were assessed histologically based on a scoring system. IL-10 administration (in recombinant form or by gene transfer) inhibited the development of fibrous airway obliteration 3 weeks after transplantation in comparison to untreated controls (p < 0.05). This was demonstrated only if the delivery was initiated 5 days after transplantation and not if it was started at the time of transplantation. A single administration of the gene construct was sufficient to achieve the desired effect. We have shown that IL-10 can prevent the development of airway fibro-obliteration in this model. Gene transfection at a site distant from a graft can be used to produce a desired effect on the graft. IL-10 may be of major importance in the control of post-transplant bronchiolitis obliterans. The timing of its administration is critical and further studies are required to determine the mechanisms underlying the observed effects of IL-10.

Bronchiolitis obliterans after lung transplantation: detection using expiratory HRCT

OBJECTIVE

The objective of this study was to determine if air trapping, as detected on expiratory high-resolution CT (HRCT), is useful as an indicator of bronchiolitis obliterans (BO) in lung transplant recipients.

MATERIALS AND METHODS

Corresponding inspiratory and expiratory HRCT images at five different levels and spirometry were obtained in 21 lung transplant recipients. Eleven patients had BO proved by transbronchial biopsy specimens; the remaining 10 patients had no pathologic or functional evidence of airways disease. Two "blinded" observers assessed the inspiratory images for the presence of bronchiectasis and mosaic pattern of lung attenuation, and the expiratory images for presence and extent of air trapping. Statistical comparison of the frequency of HRCT findings between patients with and without BO was performed using Fisher's Exact Test.

RESULTS

On inspiratory images, bronchiectasis and mosaic pattern of lung attenuation were present in 4 (36%) and 7 (64%) of 11 patients with BO, and 2 (20%) and 1 (10%) of 10 patients without BO (p>0.05 and p<0.05), respectively. The sensitivity, specificity, and accuracy of bronchiectasis and mosaic pattern for BO were 36%, 80%, and 57%, and 64%, 90%, and 70%, respectively. On expiratory images, air trapping was found in 10 of 11 (91%) patients with BO compared to 2 of 10 (20%) patients without BO (p<0.002). Air trapping was found to have a sensitivity of 91%, specificity of 80%, and accuracy of 86% for BO. Air trapping was identified in one patient with BO who had normal results of baseline spirometric function tests.

CONCLUSION

Air trapping, as detected on expiratory HRCT, was the most sensitive and accurate radiologic indicator of BO in the lung transplant population.

Preoperative and postoperative imaging in the surgical management of pulmonary emphysema

For patients with emphysema, imaging studies have been useful for diagnostic purposes and for preoperative patient selection for surgical intervention, such as bullectomy, lung transplantation, and LVRS. Chest radiography is useful in evaluating hyperinflation. Inspiratory and expiratory films are used to estimate diaphragmatic excursion and air-trapping. CT scan is used to evaluate the anatomy and distribution of emphysema throughout the lungs, providing information clinically unobtainable by other means. Both imaging techniques are useful for detecting other disease processes. Radionuclide lung scanning also provides an estimate of target areas, volume occupying but nonfunctioning lung. Cohort studies utilizing these imaging techniques have demonstrated associations between preoperative characteristics and postoperative outcome. The imaging studies, especially the chest radiograph, have also played an important role in postoperative management. Many other imaging options are available, such as HRCT scan, quantitative CT scan, and single photon emission CT scan. Other techniques, such as MR imaging, may play a future role as well.

Experimental piglet lung transplantation: histological bioptic changes and autopsy findings

To investigate difficulties in diagnosing pulmonary rejection and to create a new model to observe long-term histological consequences, 21 piglets were subjected to left single lung transplantation. Five of these transplants served as targets for unmodified rejection in piglets without immunosuppression (Group I), 13 recipients were treated with cyclosporin A, azathioprine and methylprednisolone (Group II), and in 3 cases reimplantation of an autograft was performed (Group III). In the course of postoperative graft monitoring, transthoracic/bronchial biopsies were obtained on days 3, 5, 7, 10, 14, and 20, and thereafter less frequently up to 134 days. In the unmodified rejection group, grafts consolidated in one week and histologically presented perivascular mononuclear cell infiltrates, except for one case which showed vasculitis. Lymphocytic bronchiolitis and or peribronchiolar infiltrate was present in three of the four autopsied grafts. In Group II acute rejection was detected six times in three piglets, and all except one of these specimens had a peribronchiolar component. Although no incontestable bronchiolitis obliterans developed, mild to moderate chronic obliterative vascular lesions were detected in all immunosuppressed piglets (n = 3) surviving more than 80 days. Contralateral lungs and Group III autografts showed mild changes related to the operation itself and interstitial swine endemic pneumonia (SEP). Chronic changes related to rejection were limited to the vascular wall. The mainly inflammatory bronchiolar changes are thought to present an incipient phase leading to obliterative lesions.

FK 506 'rescue' immunosuppression for obliterative bronchiolitis after lung transplantation

PRELIMINARY EXPERIENCE

In a consecutive case series (level V evidence) involving 10 recipients of unilateral lung transplantation (LT) with bronchiolitis obliterans, in conjunction with Fujisawa protocol 93-0-003, the physiologic responses to FK 506 (tacrolimus) "rescue" immunosuppression were assessed. Recipients were 22+/-18 months post-LT and demonstrated progressive allograft dysfunction that was refractory to pulsed-dose methylprednisolone therapy. All recipients received induction immunosuppression with Minnesota antilymphocyte globulin (10 to 15 mg/kg/d) for 5 to 10 days, cyclosporine (CsA) (whole-blood Abbott TDX fluorescence polarization immunoassay (Abbott Inc, Abbott Park, IL)=600 to 800 ng/mL), azathioprine (2 mg/kg/d), and prednisone (tapered to 0.2 mg/kg/d). The "rescue" regimen consisted of oral FK 506 adjusted to maintain a whole-blood Abbott IMX microparticle enzyme immunoassay (Abbott Inc, Abbott Park, IL) of 10 to 15 ng/mL with an initial increase in prednisone (1.0 mg/kg/d) during conversion that was subsequently tapered to 0.2 mg/kg/d. Spirometry was performed monthly in accordance with accepted American Thoracic Society criteria. Recipients were classified in accordance with the International Society for Heart and Lung Transplantation (ISHLT) "Working Formulation for Standardization of Nomenclature and for Clinical Staging of Chronic Dysfunction in Lung Allografts" as stages Ib (n=2), IIb (n=4), and IIIb (n=4) upon entry to the protocol. The deltaFEV1/month relationships during CsA- and FK 506-based regimens were analyzed by linear regression and compared by signed rank test (p<0.05).

RESULTS

The deltaFEV1/month slopes were -0.0687+/-0.0221 and +0.0300+/-0.033 L/mo (mean+/-SEM) for CsA and FK 506, respectively (p=0.037). Although no significant spirometric improvement was noted in most recipients, no further decline in FEV1 occurred after conversion to FK 506. Recipients with less severe chronic dysfunction (ie, obliterative bronchiolitis [OB] stages Ib and IIb) stabilized their spirometric indexes at higher levels. Two recipients with OB stage IIIb died of hypercapnic respiratory failure at 6 and 8 months after conversion.

CONCLUSIONS

The deltaFEV1/mo slopes stabilized after FK 506 conversion. Earlier conversion may be beneficial in stabilizing FEV1 at a higher plateau. Significant economic impact may be anticipated with FK 506 compared to alternative cytolytic strategies for OB. However, multicenter prospective controlled investigations are necessary to further address the potential role of FK 506 after LT (level I evidence). Furthermore, the ISHLT "Staging of OB Syndrome" may have significant clinical implications vis-à-vis prognosis and potential therapies.

Mycophenolate mofetil for obliterative bronchiolitis syndrome after lung transplantation

BACKGROUND

The development of obliterative bronchiolitis after lung transplantation portends a poor long-term outcome because of progressive decline in allograft function. There are currently no effective means of treating this condition.

METHODS

Thirteen patients in whom obliterative bronchiolitis syndrome developed after lung transplantation were treated with mycophenolate mofetil, an antimetabolite immunosuppressant, at a dose of 1.5 g orally twice daily. Patients were followed up clinically and with pulmonary function testing.

RESULTS

Duration of mycophenolate mofetil therapy ranged from 1 week to 24 months (mean duration, 11.4 months). Pulmonary function test results stabilized in the majority of patients with no significant further decline in forced expiratory volume in 1 second. Two patients died of progressive obliterative bronchiolitis, 1 patient is alive with progressive disease, and 1 patient died of an acute infection. The drug was discontinued in 2 additional patients. In no patient did severe leukopenia or cytomegalovirus infection develop; 1 patient had a fungal infection, and 7 patients experienced gastrointestinal side effects.

CONCLUSIONS

In the setting of obliterative bronchiolitis syndrome, mycophenolate mofetil is generally well tolerated and is associated with stabilization of pulmonary function test results. These findings suggest that the otherwise progressive process of obliterative bronchiolitis can be slowed.

Obliterative bronchiolitis

Obliterative bronchiolitis following lung transplantation is common and potentially devastating. Its exact cause is undefined, but multiple immune and nonimmune processes contribute to its pathogenesis. Severe acute rejection and recurrent acute rejection have been shown to confer the greatest risk for obliterative bronchiolitis, signifying the central importance of alloimmunity in the disease process. Treatment of established disease with intensification of immune suppression has been of limited benefit, so current clinical strategies include early detection and minimization of risk. As our understanding of the disease evolves, it is hoped that effective interventions targeted at specific pathogenetic steps will emerge. In the meantime, obliterative bronchiolitis remains the most important and sinister long-term complication of lung transplantation.

Experimental bronchiolitis obliterans induced by in vivo HVJ-liposome-mediated endothelin-1 gene transfer

BACKGROUND

Bronchiolitis obliterans (OB) is a lesion that results when injury to small conducting airways is repaired by a proliferation of fibrous granulation tissue. Bronchiolitis obliterans has emerged as a main cause of morbidity and mortality in the setting of lung and heart-lung transplantation. Endothelin-1 (ET-1), initially discovered as a vasoconstrictive peptide, has a mitogenic activity on vascular smooth cells and airway epithelial cells. Overproduction of endothelin has been reported in patients with OB or chronic rejection after lung transplantation. It is still undetermined whether locally overexpressed ET-1 has a potential impact in the pathogenesis of OB.

METHODS

We locally overexpressed ET-1 using ultraviolet irradiation-inactivated hemagglutinating virus of Japan (HVJ)-liposome-mediated in vivo gene transfer. Plasmid DNA of prepro-ET-1 and high mobility group 1 protein were coencapsulated in liposomes, and were introduced into airway epithelial cells by HVJ-mediated membrane fusion. Control animals received instillation of HVJ-liposome with an empty expression cassette. To confirm the efficiency of transfection, HVJ liposome with beta-galactosidase gene was introduced. The expression of ET-1 and beta-galactosidase was assessed by immunohistochemistry.

RESULTS

Bronchial epithelium alveolar cells and alveolar macrophage were stained blue (X-Gal) 1 week after in vivo gene transfer of beta-galactosidase gene, indicating beta-gal activity. In animals 1 to 2 weeks after in vivo transfection of prepro-ET-1 gene, hyperplastic connective tissue plaque was seen in the alveolar duct and small conducting airway, indicating histologically distinctive bronchiolitis obliterans. Strong ET-1-like immunoactivities were seen in the airway epithelial, hyperplastic connective tissue, and alveolar cells. No histopathologic changes were seen in the control animals.

CONCLUSIONS

These results suggested that ET-1 may play an important role in the pathogenesis of OB. The effective pharmacologic antagonist or inhibitor may possibly control the progression of disease in patients of OB.

The potential role of mast cells in lung allograft rejection

To perform a retrospective pilot study of the potential role of mast cells in acute and chronic rejection of the lung allograft, transbronchial biopsies of 29 patients with acute rejection and six patients with bronchiolitis obliterans were stained with antibodies to mast cell tryptase. The number of mast cells per unit area were counted, and compared with a control group of normal lung biopsies stained in a similar fashion. Increasing grades of acute rejection were associated with progressively more mast cells per high-power microscopic field. The presence of bronchiolitis obliterans was accompanied by the greatest numbers of mast cells. Mast cells may play a role in the acute rejection response to the lung allograft and in the development of bronchiolitis obliterans.

Bronchiolitis obliterans in ataxia-telangiectasia

Pulmonary disease was studied in four patients with ataxia-telangiectasia. Immunodeficiency was characterized by lymphopaenia, hypo-gammaglobulinaemia and decreased T-cell response to phytohaemagglutinin stimulation in mixed lymphocyte cultures. All four patients died from respiratory failure. Autopsy revealed that all four patients suffered from bronchiolitis obliterans in all lobes. Immunohistochemical examination demonstrated expression of MHC class II antigens on bronchiolar epithelium. Pulmonary infections in ataxia-telangiectasia patients included a case of mycoplasma pneumonia, one of cytomegalovirus pneumonia and one of Pseudomonas aeruginosa infection. The aetiology and immunological background of bronchiolitis obliterans are discussed. Bronchiolitis obliterans is a characteristic finding in ataxia-telangiectasia and may be due to the underlying immune deficit.

Endothelin-1 and cell proliferation in lung organ cultures. Implications for lung allografts

Endothelin-1 (ET-1) is found in bronchoalveolar lavage fluid in patients following lung transplantation. ET-1 causes contraction of isolated pulmonary vessels and bronchi and stimulates proliferation of smooth muscle cells in culture. Therefore, ET-1 could contribute to the smooth muscle hyperplasia and stromal proliferation seen in chronic rejection of lung allografts. Experiments were designed to determine whether (1) ET-1 stimulates proliferation of pulmonary tissue, (2) proliferation is increased in rejecting allotransplanted lungs, (3) endothelin-A receptors mediate the proliferative response, and (4) ET-1 is produced by activated infiltrating immunocompetent cells. Lung organ cultures were prepared from unoperated dogs and dogs with rejecting single lung allografts. Incubation of organ cultures from unoperated dogs with ET-1 (10(-9) to 10(-7) M)) increased positive staining for proliferation cell nuclear antigen (PCNA) in lung parenchyma. PCNA staining was not decreased by the endothelin-A antagonist BQ123 (10(-6) M). In addition, immunostaining for endothelin-B receptors was present in sections of unoperated but not rejecting lungs. PCNA staining in lung cultures from rejecting allotransplanted dogs was significantly greater than that from unoperated dogs. Positive immunohistochemical staining for ET-1 was found in mononuclear cells infiltrating rejecting transplanted lungs. In conclusion, exogenous ET-1 is mitogenic in lung organ cultures through receptors other than endothelin-A. Proliferation in rejecting transplanted lungs is increased compared with unoperated lungs. Mononuclear cells may be a source of endothelin-1 in the rejecting lung. ET-1, therefore could, in synergism with other cytokines, contribute to acute and chronic pathological changes seen in pulmonary rejection.

Stanford experience with obliterative bronchiolitis after lung and heart-lung transplantation

BACKGROUND

Obliterative bronchiolitis (OB) is the main chronic complication after heart-lung (HLTx) and lung transplantation (LTx), limiting the long-term success of both transplant procedures.

METHODS

Since 1981, 135 HLTxs and 61 isolated LTxs were performed in 184 patients at Stanford University.

RESULTS

The overall prevalence of OB in patients surviving longer than 3 months postoperatively was 64% after HLTx and 68% after LTx. The actuarial freedom from OB was 72%, 51%, 44%, and 29% at 1, 2, 3, and 5 years, respectively, after HLTx and LTx. An analysis of potential risk factors revealed that the frequency and severity of acute rejection episodes (p < 0.001) and the appearance of lymphocytic bronchiolitis on biopsy (p < 0.05) were significantly associated with the development of OB. With regard to diagnosis of OB, pulmonary function tests show early reductions of the forced expiratory flow between 25% and 75% of the forced vital capacity with subsequent decreases in the forced expiratory volume in 1 second. The sensitivity of transbronchial biopsies has increased to 71% since 1993. Current treatment consists of augmented immunosuppression. Concurrent acute rejection episodes or active OB on biopsy have been treated aggressively with high-dose steroid pulses. Analysis of data from 73 patients with OB after HLTx and LTx revealed actuarial 1-, 3-, 5-, and 10-year survival of 89%, 71%, 44%, and 17% versus 86%, 77%, 63% and 56% in patients without OB (p < 0.05 by log-rank analysis). The main complication and cause of death in patients with OB was superimposed respiratory tract infection, which was treated aggressively.

CONCLUSIONS

Early diagnosis of OB using pulmonary function tests or transbronchial biopsy is possible and important, because immediate treatment initiation has led to acceptable survival rates, with nearly 50% of affected patients still alive 5 years after transplantation. Current experimental research on OB suggests that immune injury is the main pathogenetic event of airway obliteration in animal models; rapamycin and leflunomide are new immunosuppressive agents that may have the potential to prevent and treat airway obliteration.

Bronchiolitis obliterans organizing pneumonia (BOOP) in lung transplant recipients

We reviewed all tissue specimens from 163 transplant patients (108 double lung transplant [DLT], 55 single lung transplant [SLT]) between November 1983 and January 1994 for abnormalities indicating bronchiolitis obliterans organizing pneumonia (BOOP) and found 17 cases (14 DLT and 3 SLT). Of the three SLTs, BOOP was diagnosed by open lung biopsy (OLB) in two and one was found at autopsy. Of the 14 DLTs, BOOP was diagnosed by transbronchial biopsy (TBB) specimens (9), OLB specimens (2), autopsy (1), TBB and OLB specimens (1), and OLB specimens and autopsy (1). BOOP was found between 1 and 43 months posttransplantation; time of survival from diagnosis was between 2 and 36 months with 9 patients presently alive. Concurrent pathologic diagnosis at the time of BOOP findings were as follows: acute rejection (7) (grade 1 [4] and grade 2 [3]), BO and grade 1 rejection (2), BO and grade 2 rejection (2), BO and Aspergillus infection (1), acute alveolar injury (1), acute alveolar injury and pulmonary embolus (1), acute rejection (grade 1) and Burkholderia cepacia pneumonia (1). No other pathologic diagnosis was found in 1 patient. In total, 11 of 17 patients (65%) had associated acute rejection. Of the 17 patients, 7 subsequently developed BO and 3 had BO before the finding of BOOP. Death occurred in 8 patients (5 DLT and the 3 SLT) between 2 and 6 months after the diagnosis. We conclude that BOOP is an important complication after lung transplantation; it was present in 13% of DLTs and 5% of SLTs. BOOP was most often associated with acute rejection.

Living-donor lobar lung transplantation experience: intermediate results

OBJECTIVE

Living-donor lobar lung transplantation offers an alternative for patients with a life expectancy of less than a few months. We report on our intermediate results with respect to recipient survival, complications, pulmonary function, and hemodynamic reserve.

METHODS

Thirty-eight living-donor lobar lung transplants were performed in 27 adult and 10 pediatric patients for cystic fibrosis (32), pulmonary hypertension (two), pulmonary fibrosis (one), viral bronchiolitis (one), bronchopulmonary dysplasia (one), and posttransplantation obliterative bronchiolitis (one). Seventy-six donors underwent donor lobectomies.

RESULTS

There were 14 deaths among the 37 patients, with an average follow-up of 14 months. Predominant cause of death was infection, consistent with the large percentage of patients with cystic fibrosis in our population. The overall incidence of rejection was 0.07 episodes/patient-month, representing 0.8 episodes/patient. Postoperative pulmonary function testing generally showed a steady improvement that plateaued by postoperative months 9 to 12. Fourteen patients who were followed up for at least 1 year underwent right heart catheterization; pressures and pulmonary vascular resistances were within normal ranges. Bronchiolitis obliterans was definitively diagnosed in three patients. Among the 76 donors, complications in the postoperative period included postpericardiotomy syndrome (three), atrial fibrillation (one), and surgical reexploration (three).

CONCLUSIONS

We believe that these data support an expanded role for living-donor lobar lung transplantation. Our intermediate data are encouraging with respect to the functional outcome and survival of these critically ill patients, who would have died without this option.

[Infections in lung transplantation]

Lung transplantation has become the therapeutic hope of terminal respiratory patients. Infections are among the main causes of morbidity and mortality in these patients. We therefore analyze infections suffered after lung transplants performed at Clínica Puerta de Hierro over a two-year period. The cases of 14 transplanted patients, 6 bilateral and 8 unilateral, were analyzed. Pre-transplant data available for all included analysis of serum antibodies to several viruses, as well as bacterial and fungal cultures, and Ziehl's sputum test. All received prophylactic antibiotic, antifungal and antiviral treatment according to protocol. The bronchial aspirate of the donor, and recipient specimens of bronchial aspirate, bronchoalveolar lavage and biopsies obtained by bronchoscopy after transplantation were cultured. Bronchoscopies were performed according to protocol, based on clinical picture. Other cultures were obtained as needed. We recorded 27 respiratory infections, among which 4 were pneumonia transmitted by the donor, 3 were tuberculosis, 3 were Aspergillus infections, 5 were cytomegalovirus pneumonitis and one, P. carinii pneumonia. Lung infections have a strong impact on outcome of lung transplant patients. Knowledge of the chronological development of infections made appropriate prophylaxis and early detection possible, such that survival during the first two years after transplantation was approximately 70% in our hospital.