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

Pneumonia

The lung is constantly exposed to airborne infectious agents due to the large surface area of approximately 100 m². Therefore pneumonia is one of the most common lung diseases. Understanding infection requires understanding the routes of infections, the way invading organisms infect epithelial cells, as well as defense mechanisms of the lung tissue acquired during evolution.

 Different variants of infectious and non-infectious pneumonias are discussed; special types of pneumonias such as granulomatous and fibrosing pneumonias are presented under separate sections. Causing organisms and other causes of pneumonias are included, and their mode of action is included as far as understood.

Interstitial lung disease associated with Equine Infectious Anemia Virus infection in horses

EIA (Equine Infectious Anemia) is a blood-borne disease primarily transmitted by haematophagous insects or needle punctures. Other routes of transmission have been poorly explored. We evaluated the potential of EIAV (Equine Infectious Anemia Virus) to induce pulmonary lesions in naturally infected equids. Lungs from 77 EIAV seropositive horses have been collected in Romania and France. Three types of lesions have been scored on paraffin-embedded lungs: lymphocyte infiltration, bronchiolar inflammation, and thickness of the alveolar septa. Expression of the p26 EIAV capsid (CA) protein has been evaluated by immunostaining. Compared to EIAV-negative horses, 52% of the EIAV-positive horses displayed a mild inflammation around the bronchioles, 22% had a moderate inflammation with inflammatory cells inside the wall and epithelial bronchiolar hyperplasia and 6.5% had a moderate to severe inflammation, with destruction of the bronchiolar epithelium and accumulation of smooth muscle cells within the pulmonary parenchyma. Changes in the thickness of the alveolar septa were also present. Expression of EIAV capsid has been evidenced in macrophages, endothelial as well as in alveolar and bronchiolar epithelial cells, as determined by their morphology and localization. To summarize, we found lesions of interstitial lung disease similar to that observed during other lentiviral infections such as FIV in cats, SRLV in sheep and goats or HIV in children. The presence of EIAV capsid in lung epithelial cells suggests that EIAV might be responsible for the broncho-interstitial damages observed.

Granulomatous lymphocytic interstitial lung disease in infancy

The authors report a case involving a child with chronic respiratory symptoms, who did not respond to conventional treatment. Low serum immunoglobin levels and pathological findings on lung biopsy revealed an unusual diagnosis for his age group. A specific treatment led to clinical improvement.

Role of microorganisms in interstitial lung disease

PURPOSE OF REVIEW

To review the role of microorganisms in interstitial lung disease (ILD) and to emphasize their importance in initiation and course of ILD.

RECENT FINDINGS

ILD can be idiopathic but often causality such as drugs or connective tissue disease can be found. Multiple microorganisms have been associated with ILD. On the one hand, pulmonary infection can cause extensive pulmonary damage with patterns of an ILD. On the other hand, microorganisms can trigger the immune system and provoke an abnormal response- not directed against the causative pathogen- that may result in ILD. Moreover, patients with ILD often are susceptible to infection, and infections can importantly influence the course of ILD. Furthermore, not only an infection but also its treatment can result in a drug-induced pneumonitis, eventually resulting in long-term lung damage.

SUMMARY

Microorganisms can initiate and/or influence the course of ILD. Early recognition, adequate diagnostic evaluation and therapy are essential to prevent permanent damage. Prevention of infection in patients with established ILD is strongly recommended.

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.

Epstein-Barr virus (EBV) gene expression in interstitial pneumonitis in Brazilian human immunodeficiency virus-1-infected children: is EBV associated or not?

To gain further knowledge on the subject we evaluated Epstein-Barr virus (EBV) gene expression and TCD4+, TCD8+, and B lymphocyte counts in lung tissue samples from 20 human immunodeficiency virus (HIV)-infected children with chronic lung disease. Twenty HIV-1 infected children with chronic pulmonary disease underwent open lung biopsy to define the diagnosis. Histological section of this material was submitted to nonisotopic in situ hybridization (ISH) using EBV-encoded RNA (EBER) 1/2 probes and TCD4+, TCD8+, and CD20+ B-cell counts by immunohistochemistry. The histology of 16 out of the 20 children (median age 53.5 months) proved to be examples of pulmonary lymphoid hyperplasia/lymphoid interstitial pneumonitis (PLH/LIP) complex, 13 of which were EBER positive, but no significant association was found (Fisher exact test P = 0.439). Four patients had non-LIP diseases (3, nonspecific interstitial pneumonia; 1, diffuse advanced alveolar damage), two being EBER negative. Nineteen children showed a predominant T-CD8+ cell response (CD4+/CD8+ <1) in lung tissue. The mean TCD4+ and theTCD4/TCD8 ratio in lung tissue were significantly higher in the sections with PLH/LIP complex, but without significant difference between EBER positive and EBER negative samples. EBV gene expression was detected in the majority of the lung samples but without significant association with PLH/LIP complex or with TCD4+, TCD8+, B cells and the TCD4+/TCD8+ ratio. Regarding the pattern of lung disease in HIV-1 infected children, associated or not to EBV, the findings are of importance concerning the possible role of EBV in the pathogenesis of PLH/LIP.

Diagnostic Pathology of Diffuse Lung Disease in Children

The pathologic classification of diffuse lung disease in children and adolescents has undergone revision in recent years in response to rapid developments and new discoveries in the field. A number of important advancements have been made in the last 10 years including the description of new genetic mutations causing severe lung disease in infants and children, as well as the description of new pathologic entities in infants. These recently described entities, including ABCA3 surfactant disorders, pulmonary interstitial glycogenosis, and neuroendocrine cell hyperplasia of infancy, are being recognized with increasing frequency. This review will include brief discussion of the etiology and pathogenesis of the major groups of diffuse lung disease in children. Histopathologic features are discussed for each of the major categories of diffuse lung disease in children, beginning with the genetic, developmental, and alveolar growth disorders common in infancy, followed by brief discussion of airway diseases, immunologic diseases, and pulmonary vascular diseases seen more commonly in older children. A protocol for handling pediatric wedge lung biopsies is also discussed, which optimizes the diagnostic yield of lung biopsies in this population.

Challenges in pulmonary fibrosis. 3: Cystic lung disease

Cystic lung disease is a frequently encountered problem caused by a diverse group of diseases. Distinguishing true cystic lung disease from other entities, such as cavitary lung disease and emphysema, is important given the differing prognostic implications. In this paper the features of the cystic lung diseases are reviewed and contrasted with their mimics, and the clinical and radiographic features of both diffuse (pulmonary Langerhans' cell histiocytosis and lymphangioleiomyomatosis) and focal or multifocal cystic lung disease are discussed.

Reactive Epstein-Barr virus-related polyclonal lymphoproliferative disorder in a patient with AIDS

Reactivation of Epstein-Barr virus infection and polyclonal expansion of lymphocytes is well-documented in solid organ and hematopoietic stem cell transplant recipients and is considered a potential precursor to lymphoma. We report an analogous case of posttransplantation polyclonal lymphoproliferative disorder in a patient with human immunodeficiency virus infection who was successfully treated with antiretroviral therapy.

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.

Pathology of interstitial lung disease

A large and diverse group of pathologic conditions manifests clinically and radiologically as diffuse parenchymal lung disease. Diffuse interstitial lung diseases (ILDs) encompass mainly inflammatory processes that involve the structural elements of this organ. Some ILDs are caused by infections, but most are the result of immunologic, environmental, or toxic mechanisms. Currently, less morbid sampling techniques have increased dramatically the probability that pulmonologists will be faced with establishing a specific and clinically relevant diagnosis using surgical lung biopsy material. Most of the concepts presented in this article have been established using this type of specimen. In the early years of surgical lung biopsy, a small number of diffuse inflammatory conditions came to light that exclusively involved the lungs and did not seem to be caused by infection, toxin, sarcoidosis, pneumoconiosis, or neoplasm. In this article, these idiopathic disorders are discussed in the context of their dominant pathologic findings rather than presented as a separate group of entities.

Pathogenesis of SIV pneumonia: selective replication of viral genotypes in the lung

Lymphocytic interstitial pneumonia of HIV-infected individuals and SIV pneumonia of macaques are both characterized by diffuse infiltration of the lungs with lymphocytes, plasma cells, and macrophages. This study was undertaken to determine whether there are specific, macrophage-tropic genotypes that selectively replicate in the lung of macaques with SIV pneumonia, as in SIV encephalitis. Using a rapid, reproducible SIV/macaque model of AIDS, 11 pig-tailed macaques were intravenously inoculated with an immunosuppressive viral strain, SIV/DeltaB670, and a macrophage-tropic molecule clone, SIV/17E-Fr, and euthanized at 3 months postinoculation. All 11 macaques had severe (6 macaques) or moderate (5 macaques) pneumonia. To identify the viral genotypes that were replicating in the lung parenchyma, bronchoalveolar lavage (BAL) cells, and peripheral blood mononuclear cells (PBMC) of each macaque, RNA was isolated and the SIV env V1 region was amplified, cloned, and sequenced. Lung homogenates and BAL cells contained a more limited repertoire of viral genotypes than PBMC. SIV/17E-Fr was the major genotype in the lungs of 5 macaques and in BAL cells of 6 macaques. The remainder of the macaques had SIV/17E-Fr and the macrophage-tropic strains of SIV/DeltaB670 clones 2 and 12. In contrast, SIV/17E-Fr was the predominant strain in the PBMC of only 3 of 11 macaques. The viral strain that predominated in PBMC was rarely the strain that predominated in the lungs (only 3 of 11 macaques). The severity of pulmonary lesions did not correlate with the levels of viral RNA in lung homogenates or in plasma. However, when only SIV/17E-Fr was expressed in the lung, the viral load in the lung was significantly higher (P = 0.016) than when SIV/DeltaB670 was present alone or in combination with SIV/17E-Fr. These data suggest that SIV pneumonia is associated with selective replication of specific macrophage-tropic genotypes in the lung and that SIV/17E-Fr has a selective advantage for replication in the lung.

Ocular manifestations of infection with the human immunodeficiency virus in an African pediatric population

PURPOSE

To describe the ocular manifestations of HIV/AIDS infection in an African pediatric population.

METHODS

From 1984 to 1990, all children with HIV infection attending the Department of Pediatrics of the 'Centre Hospitalier de Kigali', Rwanda, were referred to the Department of Ophthalmology for ophthalmic examination.

RESULTS

A total of 162 HIV-infected children were examined. The overall rate of ophthalmic involvement was 54%. The most common finding was a perivasculitis of the peripheral retinal vessels, observed in 38% of the patients. Cytomegalovirus (CMV) infection of the retina was diagnosed in three patients. Isolated cotton-wool spots of the retina were not observed. Ophthalmic herpes zoster and conjunctival xerosis responding to vitamin A administration were each seen in two patients. One third of a subset of children tested for lacrimal function had evidence of decreased tear secretion.

CONCLUSION

Our data, in agreement with other series reported in the literature, indicate that cotton-wool spots and CMV retinitis, the most common ocular manifestations of HIV/AIDS in adults, are much less prevalent in children. The high incidence of perivasculitis in the present series, not observed or only seen in a few cases in other series, suggests that this ocular sign is more prevalent in African children. Our working hypothesis is that perivasculitis of the retinal vessels, lymphoid interstitial pneumonitis, parotitis, and lacrimal gland involvement are the expression of a diffuse infiltrative lymphocytosis syndrome, similar to what has been described in adults.

Nodular lymphoid hyperplasia of the lung: a clinicopathologic study of 14 cases

Nodular lymphoid hyperplasia is a controversial entity in which its existence in the lung has been doubted. The current opinion is that most, if not all, such cases represent extranodal marginal zone B-cell lymphomas masquerading as reactive lesions. We found 14 cases of nodular lymphoid hyperplasia in the files of the Pulmonary Department at the Armed Forces Institute of Pathology from 1974 through 1998. All had clinical histories and hematoxylin-eosin slides. In 12 of 14 with paraffin blocks, we applied immunohistochemical antibodies for CD20, CD3, CD43, CD5, bcl-2, bcl-1, CD45RA, and kappa and lambda immunoglobulin light chains. Molecular genetic analysis was performed on paraffin sections in 10 of 14 by the polymerase chain reaction for rearrangements of the immunoglobulin heavy chain gene and the minor and major break-point regions of the chromosomal translocation t (14;18). There were eight women and six men ranging in age from 19 to 80 years (median, 65 yrs). Most lesions (71%) were incidental findings on routine chest x-rays. Most patients (64%) had a single lesion by chest x-ray whereas the remainder had two to three lesions, except for one patient who had "multiple" lesions. There was associated regional lymphadenopathy in five of 14 cases (36%) which, on biopsy, proved to be reactive follicular hyperplasia. The only treatment was surgical excision. Of the seven patients with follow-up information from 8 months to 6 years (mean, 30 mos), none had clinical recurrence and no patient died of disease. The histology and immunophenotype of the lesions were strikingly similar, including abundant reactive germinal centers, intense interfollicular polyclonal plasmacytosis, and a variable degree of interfollicular fibrosis. No case showed a molecular rearrangement of the immunoglobulin heavy chain gene or the minor or major break-point region of the t (14;18). We conclude that nodular lymphoid hyperplasia of the lung, although rare, does exist and deserves its place in the spectrum of reactive pulmonary lesions that ranges from follicular hyperplasia to diffuse hyperplasia of the bronchus-associated lymphoid tissue (lymphoid interstitial pneumonitis).

Effects of recombinant ovine interferon-tau on ovine lentivirus replication and progression of disease

The antiviral effects of recombinant ovine interferon-tau (roIFN-tau) were studied in 26 lambs inoculated with ovine lentivirus (OvLV) or mock-infected. Six of the OvLV-infected lambs and three of the mock-infected lambs were treated with 10(6) antiviral units (AVU) per kg roIFN-tau daily for 30 days starting at day 0 post-inoculation (p.i.) and twice a week thereafter (early treatment). Six of the OvLV-infected lambs and three of the mock-infected lambs were treated with 10(6) AVU/kg roIFN-tau daily for 30 days starting at day 150 p.i. and twice a week thereafter (late treatment). Six OvLV-infected and two mock-infected lambs were treated either early or late with placebo. Cell-associated viraemia was quantified by an end-point dilution method. The weekly antibody response against OvLV proteins was studied by ELISA. All experimental animals were killed at 27 weeks p.i. and histological sections of lung were scored for the degree of lymphoid interstitial pneumonia (LIP). A 90% reduction in OvLV titres was detected at 4 weeks post-treatment in lambs that received early roIFN-tau treatment (P<0.01). Differences in virus titres were also found at weeks 2 and 6 (P<0.05). Scores for LIP degree were higher in infected lambs treated with placebo or late roIFN-tau than in the mock-infected lambs or in the infected lambs that received early roIFN-tau (P<0.05). LIP scores were not different between mock-infected lambs and infected lambs that received early roIFN-tau. These results indicate that roIFN-tau curtails OvLV replication in vivo and reduces the likelihood of development of lentivirus-induced LIP when infected lambs are treated during the initial phases of OvLV infection.

Epstein-Barr virus-associated polymorphic B-cell lymphoproliferative disorders in the lungs of children with AIDS: a report of two cases

Patients infected with HIV experience a spectrum of lymphoproliferative disorders, including generalized reactive lymphadenopathy to atypical lymphoproliferative lesions and lymphomas. Polymorphic B-cell lymphoproliferative disorders are rare and not well documented. We studied lung lesions from two children infected with HIV: an atypical polymorphic B-cell hyperplasia in a 14-year-old boy and a malignant polymorphic B-cell lymphoma in a 21-month-old girl. Morphologically, both lung lesions revealed similar polymorphic lymphoid infiltrations with numerous mitoses in case 1 and extensive necrosis and architectural distortion in case 2. Immunophenotypic examination showed no predominance of kappa or lambda light chain in case 1 and a predominance of kappa light chain in case 2. Genotypic analysis demonstrated an absence of immunoglobulin and T-cell receptor gene rearrangements in case 1 and the presence of biallelic immunoglobulin heavy chain rearrangement and a single clonal Epstein-Barr virus (EBV) in case 2. The clinical course was indolent in case 1 and aggressive in case 2. The clinicopathologic features were similar to those of posttransplantation lymphoproliferative disorders suggesting that these lung lesions might represent an immunosuppression-related spectrum of benign to malignant diseases. EBV infection may play a role in the pathogenesis of these lesions. This study highlights the importance of the molecular characterization of AIDS-associated lymphoproliferative disorders in children in establishing a definitive diagnosis.

Pathogenesis of simian immunodeficiency virus pneumonia: an immunopathological response to virus

Although many human immunodeficiency virus-infected individuals develop lymphocytic interstitial pneumonia, the roles of host and viral factors in the pathogenesis of pneumonia are not well defined. Human immunodeficiency virus-infected children with lymphocytic interstitial pneumonia have human immunodeficiency virus-specific cytotoxic T cells in pulmonary infiltrates, increased survival time, and a reduced incidence of opportunistic infections, suggesting that lymphocytic interstitial pneumonia may reflect an effective antiviral immune response. In this study, 20 macaques were inoculated with related macrophage-tropic simian immunodeficiency viruses and examined for pulmonary lesions and virus gene expression. Ten macaques developed moderate to severe pneumonia characterized by perivascular, peribronchial, and interstitial infiltrates of lymphocytes and macrophages. Large numbers of pulmonary cytotoxic lymphocytes were demonstrated in macaques with moderate to severe pneumonia (P < 0.05) by immunostaining for TIA-1. There was no difference in viral load between macaques with moderate to severe pneumonia and those with mild to no pulmonary lesions. In five macaques inoculated with the same virus swarm, there was a significant (P < 0.05) inverse correlation between the percentage decline in CD4+ T-cell counts and the severity of pulmonary lesions. Pulmonary infiltrates of cytotoxic lymphocytes, the lack of correlation between severity of pulmonary lesions and virus gene expression, and the inverse relationship between pneumonia and inmune status suggest that simian immunodeficiency virus pneumonia may represent an immunopathological response to macrophage-tropic virus.

Interstitial lung disease in feline immunodeficiency virus (FIV) infected cats

Postmortem bronchoalveolar lavage of feline immunodeficiency virus-infected cats indicated an alveolitis process, and histological examination of their lungs confirmed the occurrence of alveolitis, parenchymatous lymphoplasmocytic infiltration and myomatosis. Similar lymphoid interstitial pneumonitis has been described in human and animal lentiviral diseases: lymphocytic interstitial pneumonitis in HIV-1-infected human beings, and maedi in sheep infected by the maedi-visna virus. Such lymphoid interstitial pneumonitis may thus be a common feature of lentiviral infections.

The pediatric pulmonary and cardiovascular complications of vertically transmitted human immunodeficiency virus (P2C2 HIV) infection study: design and methods. The P2C2 HIV Study Group

The P2C2 HIV Study is a prospective natural history study initiated by the National Heart, Lung, and Blood Institute in order to describe the types and incidence of cardiovascular and pulmonary disorders that occur in children with vertically transmitted HIV infection (i.e., transmitted from mother to child in utero or perinatally). This article describes the study design and methods. Patients were recruited from five clinical centers in the United States. The cohort is composed of 205 infants and children enrolled after 28 days of age (Group I) and 612 fetuses and infants of HIV-infected mothers, enrolled prenatally (73%) or postnatally at age < 28 days (Group II). The maternal-to-infant transmission rate in Group II was 17%. The HIV-negative infants in Group II (Group IIb) serves as a control group for the HIV-infected children (Group IIa). The cohort is followed at specified intervals for clinical examination, cardiac, pulmonary, immunologic, and infectious studies and for intercurrent illnesses. In Group IIa, the cumulative loss-to-follow-up rate at 3 years was 10.5%, and the 3-year cumulative mortality rate was 24.9%. The findings will be relevant to clinical and epidemiologic aspects of HIV infection in children.

Intrathoracic lymphoproliferative disorders and lymphoma

The spectrum of lymphoproliferative disorders is truly a continuum from benign diseases to malignant aggressive lymphomas. Remarkable advances in laboratory techniques of monoclonal antibody production and molecular biology over the last decade allow more sophisticated analysis of these diseases. It is now apparent that some entities previously labeled "benign" are actually non-Hodgkin's lymphomas. We review the current knowledge of this spectrum including the histopathologic and clinical findings, as well as the radiographic characteristics. Understanding the diseases, treatment challenges, and follow-up requirements aids the radiologist in a more efficient and cost-effective evaluation of these patients.

Visna-maedi virus-induced expression of interleukin-8 gene in sheep alveolar cells following experimental in vitro and in vivo infection

Visna-maedi virus is a lentivirus which causes inflammatory disorders in sheep, including a chronic interstitial lung disease resembling that observed in human immunodeficiency virus type 1 (HIV 1) infection. In view of our previous demonstration of the production of neutrophil chemotactic activity by alveolar macrophages, and given the lymphocytic and neutrophilic nature of the alveolar cell infiltrate in both naturally and experimentally infected animals, we hypothesized that interleukin-8 (IL8) could be a candidate for at least part of the chemotactic activity we described. In this study, we investigated IL8 mRNA expression following visna-maedi virus infection. Northern analysis of total RNA using an ovine IL8-specific probe demonstrated that the IL8 gene is upregulated in alveolar macrophages as a consequence of in vitro infection and in alveolar cells from experimentally infected animals. Using a semi-quantitative RT-PCR method, we showed that various levels of IL8 mRNA are expressed by alveolar cells from infected animals and that they correlate with the intensity of the lesions. In conclusion, visna-maedi virus is able to induce IL8 mRNA expression in sheep alveolar cells. Results from in vivo infected animals suggest that IL8 could play a role in the early build-up of visna-maedi virus-induced lesions.

Role of tissue diagnosis in pulmonary involvement in pediatric human immunodeficiency virus infection

BACKGROUND

Pulmonary complications occur commonly during HIV infection. The aim of this study was to evaluate the clinical value of lung tissue examination in the diagnosis and treatment of pulmonary disorders in children with HIV infection.

METHODS

The medical records of 347 children enrolled between January, 1990, and April, 1994, into various antiretroviral therapy protocols were reviewed to identify patients who underwent a lung biopsy.

RESULTS

Fourteen patients underwent diagnostic lung biopsies on 16 separate occasions. The most common radiologic findings were nodular infiltrates which were localized in 7 patients and diffuse in 6. Eight patients presented with fever and progressive respiratory distress unresponsive to empiric therapy, whereas the rest had progressive nodular infiltrates. The pathologic diagnoses included opportunistic infection in 7 patients, lymphocytic interstitial pneumonitis in 5, non-Hodgkin's lymphoma in 3 and interstitial fibrosis in 1. The biopsy led to a major change in the treatment of 7 patients which resulted in a significant improvement of the pulmonary process in all of them. In an additional patient the excisional biopsy proved curative.

CONCLUSIONS

When patients are selected appropriately, lung biopsy might have a significant impact on therapy and outcome in HIV-infected children with pulmonary infiltrates.

Interstitial pneumonitis in patients infected with the human immunodeficiency virus

BACKGROUND

A study was performed to identify the clinical, radiographic, and histopathological features of interstitial pneumonitis in patients infected with the human immunodeficiency virus.

METHODS

A retrospective review was made of the case notes, chest radiographs, and histopathological results of seven HIV-1 antibody positive patients with symptomatic diffuse pulmonary disease and a pathological diagnosis of non-specific interstitial pneumonitis.

RESULTS

All patients had dyspnoea, with or without cough, and chest radiographs showing diffuse infiltrates. The arterial oxygen tension ranged widely from 5.9 to 13.1 kPa. The initial clinical diagnosis was Pneumocystis carinii pneumonia in most cases. The pathological diagnosis was made by transbronchial biopsy in one case and by open lung biopsy in six cases. The interstitial pneumonitis consisted of a patchy lymphocytic infiltrate composed of B cells in focal aggregates and T cells in a more diffuse distribution. The T cell population was a mixture of CD4+ and CD8+ cells. The histological findings contrast with the more extensive infiltrate of predominantly CD8+ lymphocytes seen in HIV-associated lymphocytic interstitial pneumonitis which occurs mainly in children. The condition ran a subacute course. Three patients spontaneously improved and three improved with steroid therapy. Long term survival was less than three years, the prognosis being determined by other infective or neoplastic complications.

CONCLUSIONS

Non-specific interstitial pneumonitis usually presents with an illness resembling Pneumocystis carinii pneumonia but occurs when the CD4 and total lymphocyte counts are still preserved. The pneumonitis resolves spontaneously or responds to steroids, and does not itself lead directly to the patient's death. It does, however, appear to mark a downturn in the course of HIV infection.

Spontaneous pneumothorax in children with AIDS

The incidence of pneumothorax in HIV-infected children has not been reported. In adults with AIDS, pneumothorax has been described exclusively in association with Pneumocystis carinii pneumonia (PCP). We report the cases of three children with AIDS, one with lymphoid interstitial pneumonitis (LIP) without evidence of PCP and two with PCP, all of whom developed spontaneous pneumothorax (SP). On presentation, none of the children had any risk factors for the development of pneumothorax, but all had radiographic evidence of subpleural cystic lesions and bilateral pleural adhesions. None of the patients responded to conservative medical management, which included chest tube thoracostomy and chemical pleurodesis. Two patients underwent pleurectomy that resulted in resolution of the pneumothorax. Both patients with PCP who developed pneumothorax died, but the patient with LIP and SP has had no recurrences of any serious respiratory problems 3 years after pleurectomy and excision of the intrathoracic cysts.

Pathology of AIDS in children

AIDS in children is a multisystem disease. The various infections, degenerative, proliferative and vascular lesions can be classified into three categories based on the known, presumed or undetermined pathogenesis. The primary lesions are due to HIV infection. The associated lesions are related to direct or indirect sequelae of HIV infection or its treatment. The third category is of lesions of undetermined pathogenesis. The pediatric pathologist plays an important role in the study and management of AIDS by demonstrating new pathologic lesions, by making the etiologic diagnosis of infection in children with AIDS, and by providing clinicopathologic correlation which leads to better understanding of the disease process and its natural history. Diagnosis of neoplastic disorders is also made by the pathologist. There is a dearth of systematic pathologic study of AIDS in children in developing countries. Although no basic differences between pathologic lesions in pediatric AIDS in Western countries, and in developing countries is expected, such a study would lead to better understanding and better management of the disorder as it affects children from the developing countries.

Pulmonary pathology in AIDS: atypical Pneumocystis carinii infection and lymphoid interstitial pneumonia

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Exploration of the pulmonary circulation. Festschrift to Professor Donald Heath

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The spectrum of pathological changes in the lung in children with the acquired immunodeficiency syndrome: an autopsy study of 36 cases

We present the pulmonary findings in 36 autopsies of children affected by the acquired immunodeficiency syndrome (AIDS). Twenty-three patients were male and 13 were female, ranging in age between 3 days and 13 years. Twenty children had human immunodeficiency virus (HIV)-positive parents or parents who were at high risk of exposure (intravenous drug abusers and prostitutes), five had a history of transfusion, and one had a history of renal transplantation and blood transfusion. Clinically, the patients presented with recurrent infections, failure to thrive, hepatosplenomegaly, fever, cough, and/or hemoptysis. Histologically, specific infectious processes were the most common finding (75% of cases), with Pneumocystis carinii pneumonia being the most prevalent type of infection, followed by bacterial pneumonia. Neoplastic conditions and lymphoid interstitial pneumonia were less frequent (approximately 10% of cases). In addition, in approximately 10% of the cases the pulmonary findings were non-specific (ie, pulmonary edema and atelectasis) and probably unrelated to HIV infection. Our findings suggest that specific infectious conditions constitute the most common type of pulmonary pathology in children with AIDS. However, because there is a small percentage of children with nonspecific findings, a transbronchial biopsy is important for proper evaluation before institution of therapy.

Ovine lentiviral infection (maedi/visna) in Morocco: a serologic and postmortem survey

In an attempt to estimate the importance of maedi/visna virus infection in Moroccan sheep and to assess the relationship, if any, between seroreactivity and pulmonary lesions, an abattoir-based serologic survey was undertaken over a period of 2 years. A total of 1000 blood samples and related lungs were collected from sheep of different breeds and ages slaughtered at three major municipal abattoirs in Morocco (Casablanca, Kénitra and Rabat). The agar gel immunodiffusion test showed that the seropositivity for all samples was 24.8%. At post-mortem examination, 107 out of the 248 (43.1%) sheep scored seropositive had gross lesions of maedi; typical microscopic lesions were observed in 125 (50.4%) seropositive sheep, including the 107 with gross lesions. Of the 752 seronegative animals, only 13 (1.7%) sheep had macroscopic maedi-like lesions. Seventeen (2.2%) of these seronegative cases, including those with gross lesions, had histologic pulmonary changes consistent with maedi. No other maedi/visna-associated lesions were found during this study; however, coexisting secondary bacterial bronchopneumonia was frequently encountered. The association between serologic and pathologic findings is reported and discussed.

Cytomegalovirus and Pneumocystis carinii pneumonia in children with acquired immunodeficiency syndrome

To ascertain the effect of cytomegalovirus (CMV) infection on the course of Pneumocystis carinii pneumonia (PCP) in children with acquired immunodeficiency syndrome (AIDS), we reviewed the charts of all children with AIDS who also had a lung biopsy specimen or a bronchoalveolar lavage specimen cultured for CMV at the time PCP was diagnosed. The data indicate that children with AIDS and PCP whose cultures are positive for CMV do not have a poorer prognosis during a first episode of PCP compared with children whose cultures are negative for CMV.

Lymphoid pneumonitis in 50 adult patients infected with the human immunodeficiency virus: lymphocytic interstitial pneumonitis versus nonspecific interstitial pneumonitis

Lymphocytic interstitial pneumonitis (LIP) and nonspecific interstitial pneumonitis (NIP) are pulmonary complications of human immunodeficiency virus (HIV) infection that occur in the absence of a detectable opportunistic infection or neoplasm. We reviewed lung biopsy specimens from 50 adult HIV-infected patients, of whom four had LIP and 46 had NIP. The majority (47 of 50) of specimens from patients with NIP showed mild chronic interstitial pneumonitis (CIP/NIP), with three showing features of diffuse alveolar damage, organizing phase. In contrast to CIP/NIP, the five specimens from four patients with LIP demonstrated more extensive lymphocytic interstitial infiltrates that extended into the alveolar septal interstitium. The majority of the interstitial lymphocytes in both NIP and LIP were of T-cell origin and stained for UCHL-1. The etiologies of NIP and LIP remain unknown. Since the common opportunistic infections were excluded by routine methods, we sought, with special techniques, to investigate whether HIV, Epstein-Barr virus (EBV), or cytomegalovirus (CMV) could be identified in lung biopsy specimens from these patients. By in situ hybridization, we found one LIP specimen with expression of large amounts of HIV RNA primarily within macrophages in germinal centers; in the remaining specimens, occasional cells expressing HIV RNA were found (two LIP and four NIP). Neither CMV nor EBV was found by in situ hybridization in seven specimens; in these same specimens EBV was detected using the polymerase chain reaction in only one case of NIP, similar to results in control specimens. These results, together with the knowledge that lymphocytic pulmonary lesions may be caused by lentiviruses in humans and animals, suggest that HIV plays a significant role in the pathogenesis of both NIP and LIP in adult HIV-infected patients; in contrast, our data do not demonstrate a direct role for either EBV or CMV.

Radiology of AIDS in the pediatric patient

The Acquired Immunodeficiency Syndrome (AIDS) has involved the pediatric age group and is especially prevalent in babies born of mothers who are intravenous drug abusers or prostitutes. Approximately 30% of children born to mothers who are seropositive for the human immunodeficiency virus (HIV) will develop HIV infection. There are several important differences in children and adults with AIDS. The incubation period of the disease is shorter, and initial clinical manifestations occur earlier in children. In addition, certain infections are more common in children, and the different types of malignancy, especially Kaposi's sarcoma, are unusual in the pediatric age group. The altered immune system involves both T cells and humoral immunity and increases susceptibility to a variety of infections, particularly opportunistic organisms. In this publication the complications of pediatric AIDS involving the lungs, cardiovascular system, gastrointestinal tract, genitourinary system, and neurological system are described. The most common pulmonary complications in our experience are Pneumocystis carinii pneumonia and pulmonary lymphoid hyperplasia. The spectrum of cardiovascular involvement in pediatric AIDS includes myocarditis, pericarditis, and infectious endocarditis. Gastrointestinal tract involvement is usually due to opportunistic organisms that produce esophagitis, gastritis, and colitis. Abdominal lymphadenopathy is a common finding either due to disseminating Mycobacterium avium-intracellulare infection or nonspecific lymphadenopathy. Although cholangitis is more commonly seen in adults, it may occur in children with AIDS and, in most cases, is due to related opportunistic infections. Genitourinary infections may be the first evidence of HIV disease. Cystitis, pyelonephritis, renal abscesses, and nephropathy with renal insufficiency are complications of pediatric AIDS. A variety of neurological abnormalities may occur in pediatric AIDS. The most common cause of neurological dysfunction in children with AIDS is HIV neuropathy. We present the many complications of AIDS in children demonstrated by a variety of imaging modalities, emphasizing the importance of diagnostic imaging in children with this disease.

Virus infections of the respiratory tract in HIV-infected children

In order to determine whether the rates of respiratory viral infection and the severity of respiratory symptoms in HIV-infected children were higher than those in noninfected children, nose and throat swabs for viral isolation were taken at 3-month intervals during the first 2 years of life from 50 children born to HIV-infected women. Similar samples were obtained during the first year of life from 19 control children born to HIV seronegative mothers. Of the 50 children, five proved to be HIV-infected while 45 were presumed to be uninfected. HIV-infected children had significantly more respiratory symptoms and a higher proportion of samples from which viruses were isolated than the non-HIV-infected children. Also, more infected episodes required admission to hospital in the HIV-infected group. There was no such difference between the non-HIV-infected and the control children. Three HIV-infected children received intravenous immunoglobulin therapy. Among these the proportion of positive samples for viral isolation was greater before than after treatment began. These results suggest that HIV-infected children are more susceptible to recurrent viral infection and that passive immunotherapy may be of benefit to such children.

Lentivirus-induced pulmonary lesions in rhesus monkeys (Macaca mulatta) infected with simian immunodeficiency virus

Necropsy reports from 28 rhesus monkeys that had been experimentally infected with simian immunodeficiency virus (SIV) and that were free of cytomegalovirus were reviewed. Lung sections from 24 of these monkeys that had no etiologic agent other than SIV detected in the lung were studied in detail by histopathologic, immunohistochemical, and electron microscopic examination and by in situ hybridization. Fourteen of the monkeys were part of a serial euthanasia study, while others were euthanatized after they became moribund. The following lesions were detected: perivascular inflammation, vasculitis, interstitial pneumonia, syncytial cells, hemorrhage, fibrin exudation, and pleural fibrosis. Perivascular inflammation was the most frequent lesion and occurred as early as 2 weeks after inoculation. Severe pneumonia and numerous syncytial cells were seen only in animals euthanatized because they had become moribund. The lesions appeared to be directly due to SIV infection. SIV antigens, RNA, and virions were detected in syncytial cells and macrophages by immunohistochemical examination, in situ hybridization, and transmission electron microscopic examination, respectively. The amount of virus present was correlated with the severity of the lesions. The SIV-induced lesions were different from those of the lymphocytic interstitial pneumonia, which occurs in human immunodeficiency virus-infected children and in ovine lentivirus-infected sheep and goats.