Alveolar macrophage migration after lung transplantation

Pulmonary circulatory parameters as indices for the early detection of acute rejection after single lung transplantation

We investigated the relationship between the changes in the pulmonary blood flow and histology during acute rejection following single lung transplantation. In single lung transplantation using adult mongrel dogs, immunosuppression with cyclosporine and azathioprine was discontinued after postoperative day 14 to induce rejection. Doppler flow probes were placed adjacent to the ascending aorta and the left pulmonary artery to measure the blood flow on a daily basis. In addition, chest roentgenograms were also examined daily. The pulmonary pressure was measured using a Swan-Ganz catheter prior to and following the induction of rejection. Open lung biopsies were performed when the left pulmonary artery flow decreased to half of the prerejection value. The pulmonary artery flow decreased to 14.3% of the aortic flow 5 days after the discontinuation of immunosuppression. The graft pulmonary vascular resistance increased significantly compared to the prerejection values (P < 0.001). This was not accompanied by any abnormalities on chest roentgenography. The histology was consistent, with marked perivascular lymphocytic infiltration with little alveolar or interstitial changes. During rejection, the increased pulmonary vascular resistance in the graft was probably the result of perivascular inflammatory cell infiltration, which was seen prior to changes on chest roentgenography. Changes in the left pulmonary artery flow and histology thus appear to be closely correlated in the early stages of acute rejection.

Medical management and complications in the lung transplant recipient

Lung transplantation has evolved as a viable therapy for patients with end-stage lung disease. Improvements in surgical techniques, avoidance of rejection by effective strategies of immunosuppression, and other aspects of medical management allow successful lung transplantation, with 1-year survivorship of 70 to 93%. In this review, we address the medical management of patients who have undergone lung transplantation. The immunosuppressive protocol used at Mayo Clinic Rochester is presented, along with a discussion of the mechanisms of action and potential complications associated with the various drugs used. The recognition and treatment of early graft dysfunction, infection, rejection, stenosis of the airway anastomosis, and posttransplantation lymphoproliferative disorder are also reviewed. Careful surveillance of patients after lung transplantation helps maintain graft function and facilitates identification, treatment, and potential avoidance of complications.

Analysis of bronchoalveolar lavage from human lung transplant recipients by flow cytometry

Bronchoalveolar lavage (BAL) cells and peripheral blood leucocytes (PBL) from 24 lung transplant recipients were analysed for leucocyte subsets and expression of cell surface antigens. Total and differential white cell counts were performed on BAL, and lymphocyte subsets were evaluated in both BAL and peripheral blood. Measurement of immunofluorescence by flow cytometry was used to assess the percentage of: T cells (CD3+); T-helper cells (CD4+); T-cytotoxic/suppressor cells (CD8+); and activated lymphocytes (HLA-DR+). Lymphocyte subsets in BAL demonstrated marked differences to those in blood. A lower percentage of CD3+ and CD4+ lymphocytes were found in BAL, whereas CD8+ cells were more prevalent in BAL than in PBL. The mean CD4:CD8 ratio was significantly lower in BAL (1:1) than in blood (2.1:1). In the absence of pulmonary infection, there was a trend for a lower CD4:CD8 ratio in BAL associated with acute rejection (1.1:1) and obliterative bronchiolitis (1:1), when compared to the group with no evidence of rejection (1.4:1). In the absence of pulmonary rejection, pulmonary infection was associated with a marginally lower CD4:CD8 ratio in BAL (0.7:1), than when infection was absent (1.4:1). This difference was more evident in cases of cytomegalovirus (CMV) infection with a mean CD4:CD8 ratio of 0.3:1, compared to 1.5:1 in the absence of CMV disease (P < 0.05).

Benefits of posttransplantation monitoring of interleukin 6 in lung transplantation

To determine the predictive diagnostic value of interleukin 6 (IL-6) monitoring in lung and heart-lung transplants, we measured posttransplantation serum IL-6 levels in 17 adult lung or heart-lung transplant recipients. Posttransplantation IL-6 elevation patterns were classified into 4 groups: serum IL-6 level remained negative throughout the monitoring period (group 1; n = 1; 6%); several sharp spikes with normal baseline (group 2; n = 9; 53%); persistently high level of serum IL-6 (group 3; n = 3; 18%); and several sharp spikes of serum IL-6 elevation with abnormally high baseline (group 4; n = 4; 24%). One patient without an elevation of IL-6 (group 1) did not experience any episodes of rejection or infection. Nine patients in group 2 had 19 IL-6 spikes, 13 of which were associated with histopathologically or clinically diagnosed rejection, 3 with acute bronchitis, and 1 with diffuse alveolar damage. Three patients in group 3 had persistent infections including cytomegalovirus infection, toxic megacolon, and repeated bacterial infection during the monitoring period, and 4 in group 4 died within 3 months after transplantation. From this study it appears that a spiked elevation of IL-6 could have a predictive value in diagnosing rejection, and persistently high levels of IL-6 indicate the presence of infection. Thus, IL-6 monitoring is beneficial for lung transplant recipients.