Epstein-Barr virus and lymphoid interstitial pneumonitis: an association revisited

Relationship of cell bearing EBER and p24 antigens in biopsy-proven lymphocytic interstitial pneumonia in HIV-1 subtype E infected children

Lymphocytic interstitial pneumonia (LIP) is an uncommon histopathologic entity characterized by infiltration of the interstitium and alveolar spaces of the lung by lymphocytes and other lymphoid elements. An increased incidence of LIP has been seen in the pediatric population, especially in children with acquired immune deficiency syndrome. Our previous study supports the notion that Langerhans cells (LCs) are reservoirs for Epstein-Barr virus (EBV) in lungs of human immunodeficiency virus (HIV) subtype E-infected pediatric LIP. To further understand the pathogenesis of LIP, we studied the relationship between EBV, the suggested causative agent of LIP and HIV-1 capsid protein p24, which play an important role in the interaction with host proteins during HIV-1 adsorption, membrane fusion, and entry in surgical lung biopsy-proven LIP from 9 vertically HIV subtype E-infected pediatric patients. The dominant microscopic feature of LIP demonstrated widespread widening of alveolar septum by mononuclear inflammatory cell infiltrate, mainly composed of mature lymphocytes and plasma cells surrounding airways and expanding to the lung interstitium. EBV-encoded RNA (EBER) in situ hybridization (ISH) and p24 immunohistochemistry, performed on formalin-fixed, paraffin-embedded tissue from open lung biopsy specimens, revealed positive intranuclear EBER signals and intracytoplasmic immunostains for p24 core protein in all 9 LIP cases. By combining ISH and immunohistochemistry, these results suggest that (i) EBV/p24-carrying cells are likely involved in the development of LIP, either directly or indirectly; (ii) LCs and related dendritic cells are the main reservoir of both EBV and HIV subtype E in pediatric LIP and possibly LCs may play an important role in the recruitment of inflammatory cell infiltrates, especially T cells into these tissues; (iii) coexpression of EBV/p24 in bronchioalveolar epithelium supports the hypothesis that these cells serve as a reactivation source for both viruses to achieve greater quantities in alveolar septum and interstitium around bronchioles. These results indicate a strong association between the presence of HIV core protein p24 and expression of EBV RNA transcripts (EBER). Interactions between LCs and related dendritic cells together with T cells are important for effective HIV and EBV replications. The coexpression of both viruses could be related to the evolution of pediatric LIP in HIV subtype E infection.

Cell reservoirs of the Epstein-Barr virus in biopsy-proven lymphocytic interstitial pneumonitis in HIV-1 subtype E infected children: identification by combined in situ hybridization and immunohistochemistry

Lymphoid interstitial pneumonitis (LIP), a frequent pulmonary complication in human immune deficiency virus (HIV)-infected pediatric patients, is characterized histologically by marked infiltration of lymphoid cells. Several theories have been suggested that LIP may be caused by Epstein-Barr virus (EBV). To identify the reservoir of EBV and pathogenesis of lymphoid infiltrates in HIV subtype E infected pediatric LIP, we examined the distribution and expression of EBV in the inflammatory cell recruitment in surgical lung biopsy-proven LIP from 9 vertically HIV subtype E-infected pediatric patients. The dominant microscopic feature of LIP demonstrated widespread widening of alveolar septum by mononuclear inflammatory cell infiltrate mainly composed of mature lymphocytes and plasma cells surrounding airways and expanding to the lung interstitium. EBV-encoded RNA (EBER) in situ hybridization, performed from paraffin-embedded lung tissues, revealed positive intranuclear signals in all 9 LIP cases. Interestingly, combined immunohistochemical and in situ hybridization analyses in 6 out of 9 LIP cases revealed 30% to 50% of the Langerhans and related dendritic cells were infected with EBV, whereas <30% of the T and B cells were infected with EBV. These results suggested that a chronic antigenic stimulus of EBV played important roles in the pathogenesis of LIP in these patients. This supports the notion that Langerhans cells (LCs) are more readily infected with EBV, indicating that LCs are reservoirs for EBV in lungs of HIV subtype E-infected pediatric LIP. And possibly LCs may play an important role in the recruitment of inflammatory cell infiltrates, especially T cells into these tissues. In addition, HIV may provide a milieu or microenvironment for the evolution of LIP, which represent an immunologic response to EBV infection. Interactions between LCs and related dendritic cells together with T cells are important for effective HIV and EBV replications.

Interstitial lung disease in patients with ataxia-telangiectasia

Ataxia-telangiectasia (A-T) is an autosomal-recessive multiorgan disease characterized by progressive neurologic deterioration in which the most common causes of death are diseases of the respiratory system and cancers. The aim of this retrospective study was to delineate the clinical, radiographic, and pathologic manifestations of the chronic progressive interstitial lung disease seen in patients with A-T. The medical records of 97 patients with A-T and chronic lung disease were reviewed. Interstitial lung disease (ILD) was specifically diagnosed in 25 of 97 patients. None of these patients had evidence of an infectious process preceding the onset of their lung disease, and none had lasting clinical improvement after treatment with antibiotics. Although many medications were used to treat their ILD, only treatment with systemic corticosteroids early in the course of their illness was associated with clinical and radiographic improvement. Nineteen of these 25 patients with ILD died within 24 months of the onset of their ILD, and of 7 patients treated with corticosteroids, 5 are still alive. Recognition of interstitial lung disease in patients with A-T and its early treatment could reduce or eliminate pulmonary disease as a leading cause of death for these patients.

A 5-week-old HIV-1–exposed girl with failure to thrive and diffuse nodular pulmonary infiltrates

A 5-week-old female infant with vertical HIV-1 exposure, progressive cough, and failure to thrive was given a diagnosis of bilateral diffuse nodular lung lesions. The child was without fever, leukocytosis, anemia, peripheral adenopathy, or hepatosplenomegaly, and the results of repeated blood tests for HIV-1 DNA were negative. A needle biopsy of the lungs revealed granulomatous inflammation and giant cells, with fungal organisms suggestive of Aspergillus species. A nitroblue tetrazolium dye test performed on the patient's blood specimen demonstrated absence of dye reduction, suggesting a diagnosis of chronic granulomatous disease. Further analysis revealed that the child had a deficiency of the p47(phox) component of the nicotinamide adenine dinucleotide phosphate oxidase system. Thus this child with vertical HIV-1 exposure and diffuse pulmonary nodules actually had an autosomal recessive form of chronic granulomatous disease. This case study clearly demonstrates that children with suspected HIV-1 infection might also need evaluation for primary immunodeficiency and that the clinical immunology laboratory is a powerful adjunct in coming to a correct diagnosis.

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.

Organ-specific manifestations of HIV disease in children

The clinical manifestations of HIV disease in children affect multiple organ systems. The severity of each manifestation varies by organ system and can be related in many cases to multifactorial causes, namely HIV replication in affected tissue, concomitant opportunistic infection of the organ, effect of concurrent immunodeficiency or autoimmune mechanisms on the organ, or adverse end-organ drug effect (primary HIV therapy or prophylaxis regimens). More information is needed to understand the pathogenesis of the systemic effect of HIV on different organ systems, especially the CNS. Most clinicians hope that advances in therapeutic interventions for primary HIV will halt the progression of the organ-specific manifestations that have been outlined in this article, but such potent therapies will probably have their own unique and new effects on HIV-infected organ systems. Vigilance for organ-specific manifestations in the era of HAART is imperative to provide the best clinical outcome for HIV-infected children.

Current concepts on interstitial lung disease in children

Pediatric interstitial lung disease comprises a diverse group of rare conditions characterized by an infiltrative process, abnormal gas exchange, and restrictive lung disease. Although the disorder is similar to its adult counterpart, its course is complicated by the continued need for lung growth and differentiation in infants and children. Knowledge about the pathogenesis, prognosis, and treatment of pediatric interstitial lung disease is limited. Investigators are focusing on defining the cellular mediators of the interstitial damage and describing the role of viral infections in and possible genetic predisposition to interstitial lung disease. Clinicians continue to define the various types of interstitial lung disease and to evaluate the roles of bronchoalveolar lavage, radiography, and biopsy in diagnosis. Together, investigators are working toward the development of specific, targeted therapy that will reduce the significant morbidity and mortality seen in pediatric interstitial lung disease.