Expression of bcl-2 and Epstein-Barr virus LMP1 in lymphocytic interstitial pneumonia

A case of lymphocytic interstitial pneumonia presenting with a ground glass nodule as an initial finding

A 65-year-old woman had a ground glass nodule, which was suspicious for lung cancer, in her right lung S⁶ by chest computed tomography. For diagnosis, video-assisted thoracoscopic surgery was performed, and the specimen showed a pathological pattern of lymphocytic interstitial pneumonia (LIP). Four years after surgery, new localized ground glass shadows gradually increased on the base of the lung. However, because she had no respiratory symptoms and had normal respiratory function, she was observed with no medication. Subsequently, no other underlying diseases associated with LIP developed. The ground glass nodule was the initial lesion of LIP.

Mouse model of Epstein-Barr virus LMP1- and LMP2A-driven germinal center B-cell lymphoproliferative disease

Epstein-Barr virus (EBV) is a major cause of immunosuppression-related B-cell lymphomas and Hodgkin lymphoma (HL). In these malignancies, EBV latent membrane protein 1 (LMP1) and LMP2A provide infected B cells with surrogate CD40 and B-cell receptor growth and survival signals. To gain insights into their synergistic in vivo roles in germinal center (GC) B cells, from which most EBV-driven lymphomas arise, we generated a mouse model with conditional GC B-cell LMP1 and LMP2A coexpression. LMP1 and LMP2A had limited effects in immunocompetent mice. However, upon T- and NK-cell depletion, LMP1/2A caused massive plasmablast outgrowth, organ damage, and death. RNA-sequencing analyses identified EBV oncoprotein effects on GC B-cell target genes, including up-regulation of multiple proinflammatory chemokines and master regulators of plasma cell differentiation. LMP1/2A coexpression also up-regulated key HL markers, including CD30 and mixed hematopoietic lineage markers. Collectively, our results highlight synergistic EBV membrane oncoprotein effects on GC B cells and provide a model for studies of their roles in immunosuppression-related lymphoproliferative diseases.

Primary Pulmonary Lymphoid Lesions: Radiologic and Pathologic Findings

The pulmonary lymphoid system is complex and is composed of two compartments: the pulmonary lymphatics and the bronchus-associated lymphoid tissue (BALT). Additional important cells that function in the pulmonary lymphoid system include dendritic cells, Langherhans cells, macrophages, and plasma cells. An appreciation of the normal lymphoid anatomy of the lung as well as its immunology is helpful in understanding the radiologic and pathologic findings of the primary pulmonary lymphoid lesions. Primary lymphoid lesions of the lung arise from the BALT and are uncommon. However, they are increasingly recognized within the growing number of posttransplant patients as well as other patients who are receiving immunosuppressive therapies. Primary lymphoid lesions encompass a wide range of benign and malignant lesions. Benign lymphoid lesions of the lung include reactive lymphoid hyperplasia, follicular bronchiolitis, lymphoid interstitial pneumonia, and nodular lymphoid hyperplasia. Malignant lymphoid lesions of the lung include low-grade B-cell lymphoma of mucosa-associated lymphoid tissue (MALT), other non-Hodgkin lymphomas, and Hodgkin lymphoma. Last, a miscellaneous group of primary lymphoid lesions includes lymphomatoid granulomatosis, posttransplant lymphoproliferative disorders, acquired immunodeficiency syndrome (AIDS)-related lymphoma, and intravascular lymphoma/lymphomatosis. These lesions are best evaluated with multidetector chest computed tomography. The radiologic findings of the primary lymphoid lesions are often nonspecific and are best interpreted in correlation with clinical data and pathologic findings. The purpose of this article is to review pulmonary lymphoid anatomy as well as the most common primary pulmonary lymphoid disorders.

HIV associated Lymphocytic Interstitial Pneumonia: a clinical, histological and radiographic study from an HIV endemic resource-poor setting

Background

There is a paucity of clinical and histopathological data about HIV-associated lymphocytic interstitial pneumonitis (LIP) in adults from HIV endemic settings. The role of Ebstein-Barr virus (EBV) in the pathogenesis remains unclear.

Methods

We reviewed the clinical, radiographic and histopathological features of suspected adult LIP cases at the Groote Schuur Hospital, Cape Town South Africa, over a 6 year period. Archived tissue sections were stained for CD3, CD4, CD8, CD20 and LMP-1 antigen (an EBV marker).

Results

42 cases of suspected LIP(100% HIV-infected) were identified. 75% of patients were empirically treated for TB prior to being referred to the chest service for further investigation. Tissue samples were obtained using trans-bronchial biopsy. 13/42 were classified as definite LIP (lymphocytic infiltrate with no alternative diagnosis), 19/42 probable LIP (lymphocytic infiltrate but evidence of anthracosis or fibrosis) and 10 as non-LIP (alternative histological diagnosis). Those with definite LIP were predominantly young females (85%) with a median CD4 count of 194 (IQR 119–359). Clinical or radiological features had poor predictive value for LIP. Histologically, the lymphocytic infiltrate comprised mainly B cells and CD8 T cells. The frequency of positive EBV LMP-1 antigen staining was similar in definite and non- LIP patients [(2/13 (15%) vs. 3/10 (30%); p = 0.52].

Conclusions

In a HIV endemic setting adult HIV-associated LIP occurs predominantly in young women. The diagnosis can often be made on transbronchial biopsy and is characterized by a predominant CD8 T cell infiltrate. No association with EBV antigen was found.

The role of Bcl-2 family proteins in pulmonary fibrosis

Pulmonary fibrosis is characterized by epithelial injury, abnormal tissue repair, fibroproliferation and loss of pulmonary function as a result of a complex interaction of multiple cellular and molecular processes. There is accumulating evidence in support of a role for apoptosis in the pathogenesis of interstitial lung diseases. The Bcl-2 (B-cell lymphoma-2) family of proteins, which consists of antiapoptotic and pro-apoptotic members, is a critical regulator for apoptosis and development of pulmonary fibrosis. The association between Bcl-2 family members and various pathways and mediators has been also described in the pulmonary fibrosis. This article reviews the recent advances regarding the roles of Bcl-2 family as the apoptosis-regulatory factors in pulmonary fibrosis from human tissue studies, animal models, ex vivo and in vitro studies. Further understanding of apoptosis signaling regulation through Bcl-2 family proteins in the lung tissue may lead to better design of new therapeutic interventions for pulmonary fibrosis.

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.

Lymphocytic interstitial pneumonitis in HIV infected adults

OBJECTIVES

To describe current knowledge on the aetiology, pathology, presentation, diagnosis, and treatment of lymphocytic interstitial pneumonitis in HIV infected adults.

METHODS

A Medline search was performed using the key words "HIV," "pneumonitis," and "lymphocytes." A further search was performed with the MESH heading "interstitial lung disorders." Related articles were also searched using Pubmed.

RESULTS

Lymphocytic interstitial pneumonitis is a common complication in HIV infected children. In adults it is uncommon and is described most commonly among black African and Afro-Caribbean patients. The aetiology and pathogenesis of lymphocytic interstitial pneumonitis in HIV infection is not clear. The clinical and radiological presentations may be indistinguishable from Pneumocystis carinii infection and a lung biopsy is necessary to establish the diagnosis. Recent evidence suggests that lymphocytic interstitial pneumonitis in HIV infected patients may respond to combination antiretroviral therapy with dramatic improvements in clinical and radiological abnormalities.

CONCLUSION

Lymphocytic interstitial pneumonitis in HIV infected patients is a treatable condition. This condition should be considered in HIV infected patients presenting with respiratory symptoms as they may gain considerable benefit from antiretroviral therapy.

Lymphoid interstitial pneumonia: a narrative review

Lymphoid interstitial pneumonia (LIP) is regarded as both a disease and a nonneoplastic, inflammatory pulmonary reaction to various external stimuli or systemic diseases. It is an uncommon condition with incidence and prevalence rates that are largely unknown. Liebow and Carrington originally classified LIP as an idiopathic interstitial pneumonia in 1969. Although LIP had since been removed from that category, the most recent consensus classification sponsored by the American Thoracic Society and the European Respiratory Society recognizes that some cases remain idiopathic in origin, and its clinical, radiographic, and pathologic features warrant the return of LIP to its original classification among the idiopathic interstitial pneumonias. LIP also belongs within a spectrum of pulmonary lymphoproliferative disorders that range in severity from benign, small, airway-centered cellular aggregates to malignant lymphomas. It is characterized by diffuse hyperplasia of bronchus-associated lymphoid tissue. The dominant microscopic feature of LIP is a diffuse, polyclonal lymphoid cell infiltrate surrounding airways and expanding the lung interstitium. Classically, LIP occurs in association with autoimmune diseases, most often Sjögren syndrome. This has led to consideration of an autoimmune etiology for LIP, but its pathogenesis remains poorly understood. Persons who are seropositive for HIV, and children in particular, are at increased risk of acquiring LIP. Some studies suggest causal roles for both HIV and Epstein-Barr virus. The incidence of LIP is approximately twofold greater in women than men. The average age at diagnosis is between 52 years and 56 years. Symptoms of progressive cough and dyspnea predominate. There is great variability in the clinical course of LIP, from resolution without treatment to progressive respiratory failure and death. Although LIP is often regarded as a steroid-responsive condition, and oral corticosteroids continue to be the mainstay of therapy, response is unpredictable. Approximately 33 to 50% of patients die within 5 years of diagnosis, and approximately 5% of cases of LIP transform to lymphoma.

Classification of idiopathic interstitial pneumonias: making sense of the alphabet soup

Since Liebow and Carrington's original classification of idiopathic interstitial pneumonias, there have been controversies over which histological patterns should be included and how they relate to clinicopathological diseases such as cryptogenic fibrosing alveolitis/idiopathic pulmonary fibrosis (CFA/IPF). Because of these differences and the wealth of overlapping terminology, a consensus classification system has been proposed, devised by a group of clinicians, radiologists and pathologists. Seven histological patterns are recognized: usual interstitial pneumonia (UIP), non-specific interstitial pneumonia (NSIP), diffuse alveolar damage (DAD), organizing pneumonia (OP), desquamative interstitial pneumonia (DIP), respiratory bronchiolitis (RB) and lymphocytic interstitial pneumonia (LIP), each with a clinicopathological counterpart, the most well defined being UIP and CFA/IPF. The system is applicable both in terms of the pathologist identifying histological patterns in isolation and in terms of the pathologist's role in contributing to the final clinicopathological diagnosis. It will probably provide greater consistency in diagnosis, early studies suggesting that the system is reproducible, and also identify purer cohorts for studies investigating causation. It also highlights the fact that the 'gold standard for diagnosis' is no longer a surgical lung biopsy in isolation but more the clinicopathological conference, when clinical, imaging and histological data are jointly discussed to produce the final clinicopathological diagnosis.

Apoptosis resistant bronchoalveolar lavage (BAL) fluid lymphocytes in sarcoidosis

BACKGROUND

Sarcoidosis is a chronic granulomatous lung disease of unknown origin. The accumulation of activated T cells at sites of inflammation represents an early stage in granuloma formation. Since mechanisms governing the normal resolution of inflammatory processes are poorly understood, this study aimed to investigate the apoptotic phenotype of peripheral blood and lung T lymphocytes from patients with sarcoidosis.

METHODS

Bronchoalveolar lavage (BAL) was performed in 10 patients with active sarcoidosis and five healthy controls.

RESULTS

Virtually no lymphocyte apoptosis, as determined by annexin V or Hoechst staining, was seen in either patients or controls. Sustained caspase-3 activity in non-apoptotic BAL fluid lymphocytes of the patients was detected, however, in agreement with in vitro studies demonstrating caspase activation after T cell receptor (TCR) triggering as a physiological response required for efficient T cell activation. Only 11.0% (range 7.7-17.6) of the BAL lymphocytes from sarcoidosis patients were annexin V positive after exposure to the apoptotic stimulus tributyltin compared with 55.0% (range 42.0-62.0) of BAL lymphocytes from healthy controls (p<0.001). After anti-Fas treatment only 8.5% (range 6-10) of BAL fluid lymphocytes from patients but 45.5% (range 38-62) from healthy controls were apoptotic.

CONCLUSION

BAL fluid lymphocytes from patients with sarcoidosis display a non-apoptotic morphology associated with endogenous caspase-3 activity. They seem to be resistant to apoptosis, which might contribute to the accumulation of inflammatory cells in the lungs, persistence of inflammation, and the development and maintenance of granuloma.

CT of cystic diseases of the lung

Cystic lung diseases are caused by a number of abnormalities. Many of the cystic lung diseases and their mimics can be reliably diagnosed based on their HRCT findings. In the appropriate clinical setting this could obviate biopsy.

Early discharge of patients hospitalized with acute asthma: a controlled study

There is no consensus on the optimal length of stay and timing of release from hospital in patients admitted with acute asthma. We hypothesize that it might be safe to discharge patients from hospital once they have responded clinically to intensive anti-asthma treatment. In a non-randomized prospective controlled study, we compared two discharge protocols in consecutive patients admitted for acute severe exacerbations of bronchial asthma. Patients in group A were discharged after remission of signs and symptoms and those in group B after improvement but before complete remission of signs and symptoms. Peak expiratory flow rates (PEFR) were monitored but were not used as discharge criteria for either group. Patients with complicating disease and who were likely to be non-compliant were excluded. The length of hospital stay (LOS) and best PEFR at discharge were significantly lower in group B (87 admissions) than group A (80 admissions). The mean (+/-SD) LOS was 1.8(+/- 1) days vs. 3.5(+/- 1.4) days and best PEFR was 58(+/- 17)% predicted versus 71(+/- 15)% predicted respectively (P < 0.001 for both variables). No patient in either group relapsed within 4 weeks of discharge from hospital. We concluded that the release of asthmatics who respond promptly to intensive treatment and are compliant with medication despite incomplete resolution of symptoms, signs and PEFR at the time of discharge from hospital may not be associated with increased risk of early relapse.

Epstein-Barr virus and lymphoproliferative disease

The Epstein-Barr virus is a ubiquitous human herpesvirus that is associated with an increasing number of human malignancies. Among these are Epstein-Barr virus-associated lymphoproliferative diseases in immunocompromised patients, a spectrum of mainly B-cell diseases that range from polyclonal lymphoproliferative diseases, which resolve when immunosuppression is halted, to highly malignant lymphomas. Progress has identified Epstein-Barr virus gene products involved in B-cell transformation, variation in Epstein-Barr virus transforming genes, distinct target cell populations with differing regulation of Epstein-Barr virus expression, and selective recruitment of other supportive cell types as factors in the heterogeneity of lymphoproliferative diseases. New therapeutic approaches to treat lymphoproliferative diseases are also being developed. Finally, xenotransplantation poses new risks for the introduction of Epstein-Barr virus-like viruses and more aggressive lymphoproliferative diseases in heavily immunosuppressed patients.

Lymphocyte dynamics: caution in interpreting BAL numbers

In various allergic and inflammatory lung diseases the number and subset composition of lymphocytes in the bronchoalveolar lavage (BAL) fluid are taken as indicators of the state of the disease. The number of lymphocytes in the BAL fluid depends on three main parameters: (1) entry into the bronchoalveolar space from the different compartments of the lung, (2) persistence in the bronchoalveolar space which is modified by the rate of local proliferation and apoptosis, and (3) exit into the draining bronchial lymph node via the lymphatic system. In healthy individuals lymphocytes in the BAL fluid seem to be a stable pool: each day there is hardly any entry, local cell division or cell death and few lymphocytes emigrate from this compartment. In contrast, during inflammatory, toxic and allergic reactions all parameters can increase rapidly with more lymphocytes entering, proliferating and/or undergoing apoptosis locally. Very little is known about factors such as cytokines and chemokines which may regulate these parameters. When interpreting data on lymphocyte numbers in patients, lymphocyte dynamics in the bronchoalveolar space have to be considered, and in the future it may be possible to manipulate these lymphocyte fluxes for therapeutic purposes.