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RANTES (regulated upon activation, normally T expressed and secreted) is a chemoattractant for macrophages, memory T lymphocytes, and eosinophils. We investigated whether intrapulmonary production of the chemokine RANTES contributes to the recruitment of immune cells during lung transplantation complications. RANTES concentration was measured in bronchoalveolar lavage (BAL) fluids using an ELISA assay. It was significantly higher during CMV pneumonitis (36.2 +/- l6 pg/ml, n=12, P=0.031) and allograft rejection (31.1 +/- 8.5 pg/ml, n=27, P=0.013) than in patients without complications (9.1 +/- 2.3 pg/ml, n=22). At least some of the RANTES was produced by lung macrophages: BAL macrophages cultured for 24 hr spontaneously released larger amount of RANTES during CMV pneumonitis (140 +/- 53 pg/ml, n=8, P=0.002) and allograft rejection (84 +/- 44 pg/ml, n=11, P=0.037) than in control patients (15.2 +/- 6.5 pg/ml, n=21). Moreover, macrophages in transbronchial biopsies were labeled by an anti-RANTES mAb. RANTES production by BAL macrophages was followed in 2 patients with CMV pneumonitis. It remained high as long as CMV-induced cytopathic effects or clinical symptoms were present, but it returned to baseline as the infection was controlled. These results suggest that the intrapulmonary production of the chemokine RANTES by activated macrophages contributes to the intrapulmonary accumulation of immune cells during complications of lung transplantation.

Local activation of macrophages may play an important role in immune complications following lung transplantation. To document such a phenomenon, we have investigated the possible changes of alveolar macrophage surface antigen expression after lung transplantation. Using immunocytofluorometry, we have analyzed the phenotype of alveolar macrophages from 41 bronchoalveolar lavage fluids obtained from 19 lung transplant recipients displaying various complications. The strong expression of HLA-DR observed on almost all alveolar macrophages was similar among groups I (no complication), II (minimal acute rejection), and III (mild to severe acute rejection), but was enhanced in group IV (bronchial infection) (P < 0.03). We observed no significant variation in the monocyte lineage CD14 antigen expression among the 4 groups, and about 83% of alveolar macrophages expressed this marker strongly. Membrane expression of the 27E10 antigen that characterizes infiltrating macrophages in acute inflammatory lesions was significantly higher during mild to severe rejection episodes than in controls (P < 0.02) and during bronchial infections (P < 0.05) but not during minimal rejection. Double staining experiments confirmed that 27E10-positive cells in groups III and IV belonged to the macrophage lineage. In addition, the expression of the 27E10 antigen on cultured alveolar macrophages was found to be increased after stimulation by bacterial lipopolysaccharide or IFN-gamma. These results indicate that a particular alveolar macrophage subpopulation is activated during immune events after lung transplantation. This population, recognized by the 27E10 mAb, might be involved in cytokine production during severe acute rejection and infection episodes.

Interleukin-6 (IL-6) is a pleiotropic cytokine that is a regulator of inflammation and immunity. As production of IL-6 may be an important mechanism by which local and systemic inflammatory processes are regulated during lung transplantation, we measured this cytokine concentration in the serum and bronchoalveolar lavage fluid (BALF) collected in 27 lung recipients. IL-6 bioactivity was analyzed using a B cell hybridoma proliferation assay (B9 cell line). Three groups of clinical situations were analyzed: control lung recipients, rejections, and CMV pneumonia. Serum IL-6 concentrations (mean +/- SEM) were 24.2 +/- 3.3 U/ml in the 26 control samples. In 20 allograft rejection episodes, the serum IL-6 concentration was higher than in control samples but the difference was not significant (59.3 +/- 20.5 U/ml, P > 0.05). IL-6 serum levels were significantly increased during the 14 CMV pneumonias (61.2 +/- 11.5 U/ml, P < 0.01). In BALF, IL-6 levels were increased during CMV pneumonia (52.4 +/- 21.9 U/ml BALF), and to a lesser extent during rejection events (14.1 +/- 3.7 U/ml BALF), as compared with controls (5.6 +/- 1.6 U/ml BALF, P < 0.005, and P < 0.05, respectively). Similar results were observed when IL-6/albumin and IL-6/urea ratios were determined so as to compensate for possible dilution effects in BALF. IL-6 in BALF was produced in situ during CMV pneumonia as shown by in situ hybridization experiments that revealed a significant number of IL-6 gene-expressing alveolar cells in this condition. IL-6 concentrations in the serum and in the BALF were compared. There was no correlation between serum and BALF IL-6 concentrations, showing that serum IL-6 levels do not accurately reflect intrapulmonary IL-6 levels do not accurately reflect intrapulmonary IL-6 production. Thus IL-6 is produced within lung transplants during CMV pneumonia, and to a lesser extent during allograft rejection.

The functional status of immune cells within human transplanted lungs was analyzed during cytomegalovirus (CMV) pneumonia complicating lung and heart-lung transplantations. The expression of interleukin-1 beta (IL-1 beta) and interleukin-6 (IL-6) genes is a marker for the activation of macrophages as is that of serine esterase B (SE-B) gene for cytotoxic cells. The levels of expression of these genes by bronchoalveolar lavage (BAL) cells were determined by in situ hybridization. Eight cases of CMV pneumonia were included in this study. BAL cells from either rejection episodes (eight cases) or control transplanted patients experiencing neither infection nor allograft rejection (eight cases) were analyzed in parallel. In the control patients, virtually no cells expressed the IL-1 beta, the IL-6, or the SE-B genes. In contrast, these three genes were all expressed in samples from patients with CMV pneumonia. IL-1 beta gene-expressing cells were abundant in all infected patients (mean +/- SEM: 898 +/- 449 positive cells per 10(4) cells, p less than 0.001, compared with those in control patients). IL-6 gene-expressing cells were less numerous (92 +/- 74 positive cells per 10(4) cells) and present in five of the eight cases of CMV pneumonia. Activated cytotoxic cells were detected in seven of the eight cases of CMV pneumonia (36.5 +/- 19 SE-B gene-expressing cells per 10(4) cells, p less than 0.001). During allograft rejections (eight cases) IL-1 beta gene-expressing cells were present in all but one patient.(ABSTRACT TRUNCATED AT 250 WORDS)

To investigate whether lung 99mTc-DTPA clearance is altered during allograft lung rejection, a group of four double lung and 24 heart-lung transplant patients was studied using serial measurement of the clearance rate of aerosolized 99mTc-DTPA (DTPA-Cl), in association with pulmonary function tests, bronchoalveolar lavage, and transbronchial lung biopsies. Using histologic diagnosis as a standard, we compared 56 episodes with normal lung histology to 32 episodes with allograft lung rejection. A control group of 20 healthy nonsmokers was used to define normal DTPA-Cl. In patients with normal lung histology, DTPA-Cl was higher than in control subjects (2.62 +/- 0.25 versus 1.20 +/- 0.12 %/min; p less than 0.001). In the episodes of allograft lung rejection, DTPA-Cl increased to 3.65 +/- 0.41 %/min (p less than 0.02) as compared with episodes of normal lung histology. The change in DTPA-Cl during allograft lung rejection was correlated (r = 0.3, p less than 0.01) with the increased percentage of lymphocytes in bronchoalveolar lavage (27.8 +/- 3.5% in rejection versus 19.9 +/- 2.2% in normal histology; p less than 0.02). Sensitivity and specificity of DTPA-Cl measurement in detecting lung rejection were 69 and 82%, respectively, versus 45 and 85% for FEV1 measurement. These results suggest that DTPA-Cl monitoring could be used in conjunction with pulmonary function testing as a noninvasive approach for the detection of lung rejection.