The Lymphocytic Infiltrative Lung Diseases

Lymphoproliferative lung disorders: a radiologic-pathologic overview. Part I: Reactive disorders

Lymphoid tissue is a normal component of the lung and manifests as intrapulmonary lymph nodes, bronchus-associated lymphoid tissue (BALT), peripheral lymphocytic aggregates, solitary lymphocytes, and phagocytic cells. Pulmonary lymphoid lesions are thought to develop as a consequence of anomalous stimulation and response of the bronchus-associated lymphoid tissue and manifests as a spectrum of lymphoproliferative disorders that may be reactive or neoplastic. Reactive disorders are polyclonal abnormalities and include nodular lymphoid hyperplasia, lymphocytic interstitial pneumonia, follicular bronchiolitis, angiofollicular hyperplasia, and enlarged intrapulmonary lymph nodes. Affected patients are often asymptomatic. Imaging findings include focal nodules, diffuse bilateral centrilobular nodules, and hilar or mediastinal masses.

Malignant and benign lymphoid lesions of the lung

Lymphoid lesions of the lung produce a complex of problems for the practicing pathologist. Although these lesions are eventually referred to hematopathologists, it is still the general surgical pathologist who first encounters them and confronts the problem of formulating an initial diagnosis. Over the last 20 years there has been a revolution in our knowledge of the classification and natural history of the pulmonary lesions, a plethora of information which warrants a thorough review. The purpose of this discussion is to report the clinical features and courses, pathologic features and, when known, etiologies or pathogenesis of the major "primary" pulmonary lymphoid lesions and present a brief approach to differential diagnosis. I will divide the lesions into malignant and benign, discussing each in turn.

Pneumonia intersticial linfocítica: correlação da tomografia computadorizada de alta resolução com a anatomopatologia

A proposta do trabalho é apresentar os achados radiológicos observados na tomografia computadorizada de alta resolução do tórax de dois pacientes com pneumonia intersticial linfocítica e correlacioná-los com os aspectos anatomopatológicos, obtidos a partir de biópsias a céu aberto. Um dos pacientes mostrou, na tomografia, basicamente opacidades em vidro fosco difusas, e o outro tinha infiltração ao longo das bainhas conjuntivas peribroncovasculares. Na anatomopatologia o padrão predominante foi o de infiltração intersticial, especialmente ao longo dos septos alveolares, por linfócitos policlonais. O estudo mostrou estreita correlação entre os achados anatomopatológicos e aqueles observados na tomografia computadorizada de alta resolução do tórax.

Differential Monocyte Chemoattractant Protein-1 and Chemokine Receptor 2 Expression by Murine Lung Fibroblasts Derived from Th1- and Th2-Type Pulmonary Granuloma Models

Recent studies suggest that monocyte chemoattractant protein-1 (MCP-1) is involved in fibrosis through the regulation of profibrotic cytokine generation and matrix deposition. Changes in MCP-1, C-C chemokine receptor 2 (CCR2), procollagen I and III, and TGF β were examined in fibroblasts cultured from normal lung and from nonfibrotic (i.e., Th1-type) and fibrotic (i.e., Th2-type) pulmonary granulomas. Th2-type fibroblasts generated 2-fold more MCP-1 than similar numbers of Th1-type or normal fibroblasts after 24 h in culture. Unlike normal and Th1-type fibroblasts, Th2-type fibroblasts displayed CCR2 mRNA at 24 h after IL-4 treatment. By flow cytometry, CCR2 was present on 40% of untreated Th2-type fibroblasts, whereas CCR2 was present on <20% of normal and Th1-type fibroblasts after similar treatment. IL-4 increased the number of normal fibroblasts with cell-surface CCR2 but IFN-γ-treatment of normal and Th2-type fibroblasts significantly decreased the numbers of CCR2-positive cells in both populations. Western blot analysis showed that total CCR2 protein expression was markedly increased in untreated Th2-type fibroblasts compared with normal and Th1-type fibroblasts. IL-4 treatment enhanced CCR2 protein in Th1- and Th2-type fibroblasts whereas IFN-γ treatment augmented CCR2 protein in normal and Th1-type fibroblasts. All three fibroblast populations exhibited MCP-1-dependent TGF-β synthesis, but only normal and Th2-type fibroblasts showed a MCP-1 requirement for procollagen mRNA expression. Taken together, these findings suggest that lung fibroblasts are altered in their expression of MCP-1, TGF-β, CCR2, and procollagen following their participation in pulmonary inflammatory processes, and these changes may be important during fibrosis.

Lung adenocarcinoma in lymphocytic interstitial pneumonitis associated with primary Sjögren's syndrome

We experienced a rare case of lung adenocarcinoma associated with lymphocytic interstitial pneumonitis caused by primary Sjögren's syndrome. A 78-year-old woman was referred to our hospital because of progressive sicca syndrome and nodular opacities in the right lower lobe on chest radiograph. This patient was diagnosed as primary Sjögren's syndrome by a labial gland biopsy and classical clinical features including xerophthalmia, xerostomia and immunoserological findings. Pathological findings including immunohistochemical studies in a surgically resected lung revealed adenocarcinoma in lymphocytic interstitial pneumonitis associated with primary Sjögren's syndrome. There was no evidence of malignant lymphoma in the lymph nodes or resected lung tissue. Pulmonary involvement of Sjögren's syndrome is now regarded both clinically and histopathologically as a wide spectrum of lymphoproliferative disorders ranging from benign to malignant. However, lung cancer associated with primary Sjögren's syndrome, as in our case, has apparently not been reported previously.

Novel roles for chemokines and fibroblasts in interstitial fibrosis

BACKGROUND

Regardless of its involvement in either wound healing or excessive fibrosis, the interstitial fibroblast can now be considered an important early participant in inflammatory responses. Although it is recognized that certain immune cells and proinflammatory mediators are intricately linked to fibrotic disease, little is presently known about the manner in which these mediators and cells are orchestrated to a fibrotic finale. Experimental studies have shown that interstitial fibroblasts are capable of participating in an inflammatory response by promoting direct fibroblast-to-immune cell communication and/or modulating the release of soluble mediators that are mutually recognized by both types of cells.

METHODS

Primary cultures of murine fibroblasts were recovered from either normal tissue or tissue undergoing a cell-mediated inflammatory response. These stromal cells were assessed for the expression of various cytokines and chemokines indicative of a type 1 or type 2 response. In addition, the fibroblasts were co-cultured with mononuclear cells to assess the cell-to-cell communication.

RESULTS

Fibroblasts recovered from different cell-mediated inflammatory responses demonstrated a dramatic alteration in their cytokine profile. Fibroblasts recovered from the type 2 immune response produced high levels of monocyte chemotactic protein-1 (MCP-1), as compared to the normal fibroblasts and fibroblasts recovered from the type 1 lesion. Mononuclear cells co-cultured with fibroblasts induced a contact-dependent expression of elevated levels of chemokines, especially the macrophage-derived MIP-1 alpha. Thus, both fibroblasts themselves and fibroblasts co-cultured with immune-inflammatory cells have the ability to participate in the maintenance of an inflammatory response via the expression of chemokines.

CONCLUSIONS

Our laboratory and others have addressed the role of chemotactic cytokines or chemokines in the fibrotic process, and have demonstrated that fibroblasts are capable of modulating the activation of various immune cells that have been implicated in fibrotic disease. In addition, the interstitial fibroblast is capable of regulating its own behavior within the interstitial environment via the expression of chemokines and chemokine receptors. Thus, novel strategies aimed at preventing fibrotic disease will likely need to address the early engagement of inflammatory cells by fibroblasts, and possibly modulate the ability of fibroblasts to generate and/or recognize profibrotic signals supplied by chemokines.

Monocyte Chemoattractant Protein-1 Synthesis by Murine Lung Fibroblasts Modulates CD4+ T Cell Activation

This study addressed the role of endogenous monocyte chemoattractant protein-1 (MCP-1) in Ag-stimulated lymphokine synthesis and proliferation by CD4+ T cells during their coculture with purified lung fibroblasts or splenic macrophages. Initial experiments showed that fibroblasts exposed to IL-4, TNF α, or IL-4 and TNF-α (all at 10 ng/ml) for 24 h released five- to eightfold more MCP-1 than similarly treated splenic macrophages. In 72-h coculture experiments, the synthesis of IL-4 by OVA-activated CD4+ T cells added to lung fibroblasts or splenic macrophages was significantly inhibited when endogenous MCP-1 was neutralized using polyclonal anti-MCP-1 antiserum. In these same cocultures, IFN-γ levels were significantly enhanced. Similarly, IFN-γ levels were significantly enhanced in 72-h cocultures of a purified peptide derivative-activated CD4+ Th1 clone and lung fibroblasts or splenic macrophages following immunoneutralization of MCP-1. In separate experiments, the selective inhibition of MCP-1 synthesis by lung fibroblasts and splenic macrophages using an MCP-1 antisense oligonucleotide significantly enhanced the proliferation of CD4+ T cells during a 96-h coculture. Taken together, these data suggest that MCP-1 exerts an immunomodulatory effect on CD4+ T cell-derived IL-4 and IFN-γ release and CD4+ T cell proliferation during cell-to-cell interactions.

Detection of pulmonary lymphoma by bronchoalveolar lavage

A patient with bilateral interstitial infiltrates was evaluated by bronchoalveolar lavage prior to open lung biopsy. The patient was found to have lymphocytic alveolitis (34 percent lymphocytes) in which 43 percent of lymphocytes were B cells. A clonal proliferation of these B cells was suggested by the finding of monoclonal kappa light chain on the B lymphocytes. A suspected diagnosis of primary pulmonary non-Hodgkin's lymphoma was later confirmed by open lung biopsy.

Lymphocytic interstitial pneumonia in patients at risk for the acquired immune deficiency syndrome

Three patients with the acquired immune deficiency syndrome (AIDS) or AIDS-related complex and lymphocytic interstitial pneumonia are reported. All patients presented with progressive dyspnea, nonproductive cough, fever, anorexia, weight loss, and arterial hypoxemia. Chest roentgenograms exhibited bilateral diffuse reticular-nodular densities. The diagnosis of lymphocytic interstitial pneumonia was made by fiberoptic bronchoscopy or open lung biopsy. Two patients were treated with corticosteroids, with significant improvement. The third patient died of pneumonia due to Pneumocystis carinii six months after the diagnosis of lymphocytic interstitial pneumonia was established. Serum antibodies to human immunodeficiency virus (HIV) were demonstrable in the two patients in whom the test was performed. Lymphocytic interstitial pneumonia is probably another pulmonary manifestation of AIDS or AIDS-related complex. Although the clinical presentation may be identical to the more common opportunistic infections, the treatment differs, and the prognosis may be better.

Follicular bronchitis/bronchiolitis

Nineteen open lung biopsies demonstrating follicular bronchitis/bronchiolitis were reviewed with special attention to clinical manifestations. Morphologically, follicular bronchitis/bronchiolitis was represented by coalescent reactive germinal centers adjacent to airways in the absence of clinical or pathologic evidence of chronic obstructive pulmonary disease or bronchiectasis. Three clinicopathologic groups were identified: 1) patients with collagen vascular diseases, especially rheumatoid arthritis and Sjögren's syndrome; 2) patients with a familial form of the disease or with immunodeficiency syndromes; and 3) a heterogeneous group of patients with frequent peripheral blood eosinophilia, suggesting a hypersensitivity reaction. Prognosis was related to age at the time of biopsy and, to some extent, to the clinical group. Steroid therapy had inconsistent effects in all groups identified. The differential diagnosis of lymphoid lesions in the lung is also discussed.

Pathologic pulmonary findings in children with the acquired immunodeficiency syndrome: a study of ten cases

Lung tissue and tissue from the lymphoreticular system obtained at open biopsy and/or autopsy were studied in ten children with the acquired immunodeficiency syndrome (AIDS). One or both parents of nine of the children had AIDS or risk factors for AIDS. The remaining child had hemophilia. The following pulmonary lesions were seen: 1) diffuse alveolar damage (DAD), 2) Pneumocystis carinii and/or cytomegalovirus pneumonitis, 3) lymphoid interstitial pneumonitis (LIP), and 4) desquamative interstitial pneumonitis (DIP). Combinations of such factors as mechanical ventilation, oxygen therapy, and opportunistic infection played a role in the pathogenesis of DAD. Opportunistic infections were related to the defective cell-mediated immunity in these children. The clinical, epidemiologic, immunologic, and pathologic features of the thymuses of these patients indicate that the immune deficiency was unlikely to have been of congenital origin. The immunologic abnormalities may also have been related to the pathogenesis of LIP and DIP. Neither LIP nor DIP has been described in adults with AIDS. Open lung biopsy is of practical importance in the diagnosis and treatment of pulmonary disease in children with AIDS.

Lymphoid interstitial pneumonia after allogeneic bone marrow transplantation. A possible manifestation of chronic graft-versus-host disease

Interstitial pneumonia (IP) is a frequent and serious complication of bone marrow transplantation with a median time of onset about 2 months posttransplant. Most cases result either from toxicity of radiation and chemotherapy or from infection with pathogens such as cytomegalovirus. Described are two patients with chronic graft-versus-host disease (GVHD) who presented with late-onset IP 242 and 632 days posttransplant. Histologic examination of lung biopsy specimens disclosed a lymphoid interstitial pneumonia (LIP) in both cases. The major lymphocyte subset found in bronchoalveolar lavages and lung tissue was OKT8(+) and showed a positive dot staining for acid phosphatase. Contrary to peripheral blood mononuclear cells, most OKT8(+) lymphocytes in the lungs were OKT3(-). Since acute GVHD lesions are mediated mainly by cytotoxic T-lymphocytes, our data suggest that LIP in marrow-grafted patients may be a manifestation of chronic GVHD. It should be distinguished from the more common types of IP encountered following bone marrow transplantation.

Pathology of suspected acquired immune deficiency syndrome in children: a study of eight cases

Biopsy and/or autopsy material from lymphoreticular and other organs was studied in 8 children with suspected acquired immune deficiency syndrome (AIDS). One or both parents of each of these children had one or more of the recognized risk factors for AIDS, such as intravenous drug abuse, prostitution, Haitian origin. The following histologic patterns were noted in the lymph nodes: (1) follicular hyperplasia with normocellular paracortex, (2) follicular hyperplasia with depletion of paracortex, and (3) atrophy of follicles with depletion of paracortex. Lymphoid interstitial pneumonitis (LIP), a previously unreported lesion in AIDS, was present in 4 cases. It is suggested that the pulmonary lymphoid lesion may be part of a more generalized lymphoid hyperplasia involving B cells. The gross and microscopic features of the thymus, available in 2 of the 8 cases, indicated that the immunologic defect in these children was not of congenital type. Pathologic findings can be helpful in the diagnosis of the syndrome when correlated with clinical and immunologic features of suspected cases and of the pulmonary lesion. The latter is of importance in deciding the type of therapy to be given for the pulmonary disease process.