Paula Pinkston

Spontaneous Release of Interleukin-2 by Lung T Lymphocytes in Active Pulmonary Sarcoidosis

We investigated the possible role of interleukin-2, a T-cell product that stimulates the clonal increase of responsive T lymphocytes, in the pathogenesis of pulmonary sarcoidosis. We obtained mononuclear effector cells from the lungs of 10 patients with sarcoidosis and high-intensity alveolitis, 17 patients with sarcoidosis and low-intensity alveolitis, 3 patients with idiopathic pulmonary fibrosis, and 10 normal controls. Lung cells from the group with sarcoidosis and low-intensity alveolitis, from the group with idiopathic pulmonary fibrosis, and from the controls produced insignificant amounts of interleukin-2. However, lung cells from 9 of 10 patients with sarcoidosis and high-intensity alveolitis spontaneously released interleukin-2, and in a proportion that correlated with the proportion of T cells in the lung washings (P less than 0.01). Blood T cells from the same patients did not release interleukin-2. To determine whether release of interleukin-2 by the lung T cells had a biologic effect in vivo, we measured T-lymphocyte replication in the lungs of patients and controls. The lung T lymphocytes replicated at a rate that was several times higher in the patients with sarcoidosis and high-intensity alveolitis than in the other patient groups or the controls (P less than 0.01). These observations suggest that the release of interleukin-2 by lung T cells has a central role in increasing the numbers of lung T cells in active pulmonary sarcoidosis.

Reduced binding and phagocytosis of Pneumocystis carinii by alveolar macrophages from persons infected with HIV-1 correlates with mannose receptor downregulation.

The macrophage mannose receptor, a pattern recognition molecule and component of innate immunity, mediates binding and phagocytosis of Pneumocystis carinii and likely represents an important clearance mechanism in the lungs of immunocompetent hosts. The purpose of this study was to examine the ability of alveolar macrophages from HIV-infected individuals to bind and phagocytose P. carinii, and to investigate the role of the macrophage mannose receptor in mediating this interaction. Compared with healthy individuals, alveolar macrophage phagocytosis of P. carinii from HIV+ persons was reduced up to 74% (P = 0.02), primarily reflecting a reduction in the number of organisms associated with each macrophage (P = 0.019). Furthermore, macrophages from HIV+ individuals demonstrated up to an 80% (P < 0.05) reduction in mannose receptor surface expression and endocytosis. Mannose receptor affinity was unaltered, and mRNA levels were modestly reduced (P < 0.05). Cells from HIV+ individuals with CD4(+) counts < 200 cells/mm3 (representing individuals at high clinical risk for P. carinii pneumonia) demonstrated the lowest levels of P. carinii phagocytosis and mannose receptor endocytosis. In vitro HIV infection of alveolar macrophages from healthy individuals reduced mannose receptor endocytosis to 53.2% (P < 0.05) and P. carinii binding and phagocytosis to 67.4% (P < 0.05) of control. Our studies suggest that HIV infection may alter innate immunity in the lungs, and that impaired alveolar macrophage mannose receptor-mediated binding and phagocytosis of P. carinii may contribute to the susceptibility of HIV-infected individuals to this opportunistic pulmonary pathogen.

Natural killer cells are present in the normal human lung but are functionally impotent.

The lung is affected by disorders in which natural killer (NK) cells are thought to play an important defensive role. This study, however, demonstrated that normal lung lymphocytes actually express very little NK cell activity (P less than 0.001 compared with blood lymphocytes). This was true independent of the NK-sensitive target used (K562, U937, MOLT-3, or Daudi). This lack of lung lymphocyte NK activity occurred even though the proportions of lymphocytes in the normal lower respiratory tract with the morphology (large granular lymphocytes) and surface antigen markers of NK cells were similar to that of blood (P greater than 0.5). Although normal lung lymphocytes bound to known NK-sensitive targets, they did not lyse these cells (P less than 0.001 compared with blood), which suggested that the lack of lung NK cell activity resulted from a relative inability of lung NK cells to destroy their targets. While the mechanisms of this functional impotence of lung NK cells are not clear, normal human alveolar macrophages and lower respiratory tract epithelial lining fluid exerted a profound suppressive effect on blood NK cell activity (P less than 0.001 for both) by inhibiting their ability to lyse target cells after binding (P less than 0.001). Though impotent initially, when incubated for 24 h in medium alone, normal lung lymphocytes demonstrated markedly enhanced NK activity (P less than 0.02), which suggested that lung NK cells do have the potential to express NK activity. Interleukin-2 (IL-2) further augmented this effect (P less than 0.05), but gamma interferon did not (P greater than 0.2). Consistent with this observation, lung lymphocytes from patients with active sarcoidosis, a disease in which lung lymphocytes are spontaneously releasing IL-2, did express NK cell activity (P less than 0.01). These studies suggest that although NK cells are present in the normal lung, they are functionally inactive, due, at least in part, to local inhibitory influences. In the presence of IL-2, however, lung NK cell activity is expressed, which suggests that lung NK cell activity can be modulated.

Acute tropical pulmonary eosinophilia. Characterization of the lower respiratory tract inflammation and its response to therapy.

Although acute tropical pulmonary eosinophilia (TPE) is well recognized as a manifestation of filarial infection, the processes that mediate the abnormalities of the lung in TPE are unknown. To evaluate the hypothesis that the derangements of the lower respiratory tract in this disorder are mediated by inflammatory cells in the local milieu, we utilized bronchoalveolar lavage to evaluate affected individuals before and after therapy. Inflammatory cells recovered from the lower respiratory tract of individuals with acute, untreated TPE (n = 8) revealed a striking eosinophilic alveolitis, with marked elevations in both the proportion of eosinophils (TPE 54 +/- 5%; normal 2 +/- 5%; P less than 0.001) and the concentration of eosinophils in the recovered epithelial lining fluid (ELF) (TPE 63 +/- 20 X 10(3)/microliter; normal 0.3 +/- 0.1 X 10(3)/microliter; P less than 0.01). Importantly, when individuals (n = 5) with acute TPE were treated with diethylcarbamazine (DEC), there was a marked decrease of the lung eosinophils and concomitant increase in lung function. These observations are consistent with the concept that at least some of the abnormalities found in the lung in acute TPE are mediated by an eosinophil-dominated inflammatory process in the lower respiratory tract.

Localized Eosinophil Degranulation Mediates Disease in Tropical Pulmonary Eosinophilia

ABSTRACT To explore the mechanisms underlying the eosinophil-mediated inflammation of tropical pulmonary eosinophilia (TPE), bronchoalveolar lavage (BAL) fluid, serum, and supernatants from pulmonary and blood leukocytes (WBC) from patients with acute TPE (n = 6) were compared with those obtained from healthy uninfected individuals (n = 4) and from patients with asthma (n = 4) or elephantiasis (n = 5). Although there were no significant differences in the levels of interleukin-4 (IL-4), IL-5, IL-13, eotaxin, granulocyte-macrophage colony-stimulating factor, RANTES, or eosinophil cationic protein, there was a marked increase in eosinophil-derived neurotoxin (EDN) both systemically and in the lungs of individuals with TPE compared to each of the control groups (P < 0.02). Moreover, there was a compartmentalization of this response, with EDN levels being higher in the BAL fluid than in the serum (P < 0.02). Supernatants from WBC from either whole blood or BAL cells were examined for chemokines, cytokines, eosinophil degranulation products, and arachidonic acid metabolites. Of the many mediators examined—particularly those associated with eosinophil trafficking—only EDN (in BAL fluid and WBC) and MIP-1α (in WBC) levels were higher for TPE patients than for the non-TPE control groups (P < 0.02). These data suggest it is the eosinophilic granular protein EDN, an RNase capable of damaging the lung epithelium, that plays the most important role in the pathogenesis of TPE.

Effects of in vitro exposure to nitrogen dioxide on human alveolar macrophage release of neutrophil chemotactic factor and interleukin-1

To evaluate the potential toxic and immunologic effects of nitrogen dioxide (NO2) exposure on cells from the lower respiratory tract, normal human alveolar macrophages obtained by bronchoalveolar lavage were exposed to increasing concentrations of NO2 using an in vitro exposure system. Alveolar macrophages exposed to 5, 10, or 15 ppm NO2 for 3 hr showed no difference in cell viability when compared to air-exposed macrophages. In addition, the spontaneous release of neutrophil chemotactic factor (NCF) was not changed by NO2 exposure, nor was there any effect on the ability of alveolar macrophages to release increased amounts of NCF following stimulation with activated zymosan. Furthermore, alveolar macrophages did not spontaneously release interleukin-1 (IL-1) following air or NO2 exposure. When stimulated with influenza virus both air- and NO2-exposed cells released increased amount of IL-1, but was no significant difference in the amount of IL-1 released by air- and NO2-exposed alveolar macrophages. Thus, although NO2 exposure is known to incite an inflammatory response in the lower respiratory tract, using the in vitro exposure system described in this study we were unable to demonstrate a direct toxic effect of NO2 on viability or any NO2-induced change in the release of the immunoregulatory molecules NCF and IL-1.

Infiltration of the lower respiratory tract by helper/inducer T lymphocytes in HTLV-1-associated adult T-cell leukemia/lymphoma.

The human T-cell lymphotropic virus type 1 (HTLV-1) is the causative agent of adult T-cell leukemia/lymphoma (ATLL), a disorder in which peripheral blood and multiple organs are infiltrated by malignantly transformed T lymphocytes. We investigated the nature of pulmonary disease in a patient with serologic evidence of HTLV-1 infection. In this case, endobronchial biopsy specimens showed infiltration of the bronchial mucosa by pleomorphic cells exhibiting a high degree of nuclear irregularity. These cells were morphologically identical in appearance to malignant cells found in peripheral blood and infiltrating the dermis, expressed the OKT4/Leu3 phenotype and the receptor for interleukin 2, and, by analogy to gene rearrangement studies on leukemic blood cells, were monoclonal in origin. However, in situ hybridization of endobronchial biopsy specimens with full-length HTLV-1 probes failed to detect retroviral RNA or proviral DNA. These studies indicate that T lymphocytic involvement of the lower respiratory tract in HTLV-1-associated ATLL is characterized by expression of a malignant phenotype despite the inability to document actual cellular infection with this retrovirus by a molecular hybridization technique.