Possible role of human herpesvirus 8 in the lymphoproliferative disorders in common variable immunodeficiency.

Patients who have common variable immunodeficiency (CVID) and granulomatous/lymphocytic interstitial lung disease (GLILD) are at high risk for early mortality and B cell lymphomas. Infection with human herpes virus type 8 (HHV8), a B cell lymphotrophic virus, is linked to lymphoproliferative disorders in people who have secondary immunodeficiencies. Therefore, we determined the prevalence of HHV8 infection in CVID patients with GLILD. Genomic DNA isolated from peripheral blood mononuclear cells was screened by nested- and real time-quantitative PCR (QRT-PCR) for the presence of HHV8 genome. It was positive in 6/9 CVID patients with GLILD (CVID-GLILD), 1/21 CVID patients without GLILD (CVID-control), and no patients receiving intravenous gamma globulin (n = 13) or normal blood donors (n = 20). Immunohistochemistry (IHC) demonstrated expression of the latency-associated nuclear antigen-1 (LANA-1) in the biopsies of the lung, liver, and bone marrow of four patients with CVID-GLILD. One CVID-GLILD patient developed a B cell lymphoma during the course of the study. QRT-PCR demonstrated high copy number of HHV8 genome and IHC showed diffuse staining for LANA-1 in the malignant lymph node. HHV8 infection may be an important factor in the pathogenesis of the interstitial lung disease and lymphoproliferative disorders in patients with CVID.

The cancer paradigm of severe pulmonary arterial hypertension.

The plexiform lesions of severe pulmonary arterial hypertension (PAH) are similar in histologic appearance, whether the disease is idiopathic or secondary. Both forms of the disease show actively proliferating endothelial cells without evidence of apoptosis. Here, we discuss the pathobiology of the atypical, angioproliferative endothelial cells in severe PAH. The concept of the endothelial cell as a "quasi-malignant" cell provides a new framework for antiproliferative, antiangiogenic therapy in severe PAH.

Expression of human herpesvirus 8 in primary pulmonary hypertension.

BACKGROUND: Severe pulmonary hypertension constitutes a group of diseases characterized by complex, lumen-occluding vascular lesions that develop in genetically susceptible persons. The only viral infection associated with severe pulmonary hypertension has been that due to human immunodeficiency virus type 1, but neither the viral genome nor viral antigens have been demonstrated in pathologic lesions. METHODS: We examined lung-tissue samples from 16 patients with sporadic primary pulmonary hypertension and 14 patients with secondary pulmonary hypertension for evidence of infection with human herpesvirus 8 (HHV-8). HHV-8 infection was ascertained immunohistochemically with use of an antibody directed against latency-associated nuclear antigen 1 (LANA-1), and a polymerase-chain-reaction (PCR) assay was performed on lung DNA to detect the viral cyclin gene of HHV-8. Sequence analysis was also performed. RESULTS: In lung tissue from 10 of 16 patients with primary pulmonary hypertension (62 percent), cells within the plexiform lesions as well as cells outside the lesions were positive for LANA-1 on immunohistochemical analysis. Tissue from the same 10 patients contained viral cyclin on PCR analysis. No LANA-1 was detected in lung tissue from patients with secondary pulmonary hypertension, although one such patient had PCR evidence of viral cyclin. Plexiform lesions from patients with primary pulmonary hypertension had a histologic and immunohistochemical resemblance to cutaneous Kaposi's sarcoma lesions. CONCLUSIONS: The spectrum of trigger factors and molecular mechanisms leading to severe pulmonary hypertension and the formation of plexiform lesions is apparently wide, including both genetic and epigenetic factors. Our data suggest that infection with the vasculotropic virus HHV-8 may have a pathogenetic role in primary pulmonary hypertension.

Loss of caveolin and heme oxygenase expression in severe pulmonary hypertension.

Caveolae are cell plasma membrane microdomains implicated in organizing and concentrating many signaling molecules. In the lung, caveolae are in endothelium, smooth muscle, fibroblasts, and pneumocytes. Caveolin is the main structural protein of caveolae. Caveolin 1 is down-regulated in transformed cells and may be a tumor suppressor protein. Caveolin 2 is coexpressed and hetero-oligomerizes with caveolin 1. Because the cells of the plexiform lesions in severe pulmonary hypertension (PH) are phenotypically altered, we wondered whether these cells lack caveolin. We now demonstrate by immunolocalization that while caveolin is expressed in lung endothelial, smooth-muscle, and alveolar septal cells, its expression is absent or decreased in plexiform lesions and in some muscularized precapillary arterioles. In contrast, Western blot analysis of total lung extracts from patients with severe PH shows no significant reduction in caveolin. Similar to the human lung tissue, a rat model of severe PH demonstrates absent-to-decreased caveolin expression in the complex vascular lesions. Additionally, it appears that caveolin and heme oxygenase 1 (HO-1) [a heat shock protein] are co-expressed since HO-1 expression parallels caveolin expression in vascular lesions. We propose that loss of caveolin expression in the cells of the complex vascular lesions in severe PH reflects the proliferating and apoptosis-resistant nature of these cells.

Sarcoidois and pulmonary hypertension--a case report.

We report a case of severe pulmonary hypertension associated with sarcoidosis with a unique histopathological presentation. This 43-year old obese patient first presented eight years ago with complaint of dyspnea on exertion for four years and was diagnosed as primary pulmonary hypertension. Six years later, a skin biopsy performed on her left cheek to rule out squamous cell carcinoma revealed sarcoidosis. The patient was then put on steroid therapy and subsequently, the oxygen saturation improved transiently, although the mean pulmonary arterial pressure did not show improvement. The patient was then started on prostacyclin infusion and was hemodynamically stable, but the pulmonary artery pressures worsened. The patient died from complications subsequent to a diagnostic procedure. An autopsy limited to the lungs was performed and routinely prepared hematoxylin and eosin stained sections were examined. Immunohistochemical stains for CD31, factor VIII-related antigen and muscle-specific actin were performed on selected sections. The diagnosis of sarcoidosis was confirmed. However, pulmonary fibrosis was not seen. The granulomas surrounded medium- and small-sized pulmonary arteries, but did not destroy the vessel wall. Plexiform lesions indicating severe pulmonary hypertension were identified in pulmonary arteries, which were not involved by granulomas.

Pediatric trauma experience in a combat support hospital in eastern Afghanistan over 10 months, 2010 to 2011.

We reviewed the pediatric trauma experience of one Combat Support Hospital (CSH) in Afghanistan to focus on injuries, surgery, and outcomes in a war zone. We conducted a review of all pediatric patients over 10 months in an eastern Afghanistan CSH. We studied 41 children (1 to 18 years; mean, 8.5 years; median, 9 years), 28 (68.2%) with penetrating injuries. Blasts (13 patients) and burns (nine) were the most common mechanisms. At arrival 19 (46.3%) underwent endotracheal intubation, four (9.8%) had no palpable blood pressure, 10.6 per cent (four of 38) a Glasgow coma score of 5 or less, 30.6 per cent (11 of 36) base deficits of 6 or less, and 41.7 per cent (15 of 36) hematocrit 30 or less. Red cells were given in 14 (34.1%) and plasma in 11 (26.8%). Of 32 total nonburn patients, 12 (37.5%) had multiple system injuries. Three-fourths of injuries were severe (75.8% [47 of 62] Abbreviated Injury Score 3 or greater). Thirty-two patients (78.0%) required major operations: burn and wound care, orthopedic, chest, abdominal, vascular, and neurosurgical. Second operations were performed in 16 (39.0%), most often burn and orthopedic procedures. Six died (14.6%), 13 were transferred to other hospitals (31.7%), and 20 were discharged to home (48.8%; two not noted). Broad experience in operative trauma care, pediatric resuscitation, and critical care is a priority for military surgeons.

Pulmonary stromal-derived factor-1 expression and effect on neutrophil recruitment during acute lung injury.

The severe and protracted inflammation that characterizes acute lung injury (ALI) is driven by the ongoing recruitment of neutrophils to the lung. Although much of the cytokine signaling responsible for the initial phase of ALI has been elaborated, relatively little is known about the mechanisms governing the recruitment of neutrophils from the bone marrow to the lung in the later period of this disease. Given its previously described chemoattractant effects on marrow neutrophils, we investigated whether stromal-derived factor-1 (SDF-1) (CXCL12) might participate in this later phase of recruitment. Using immunohistochemistry to examine both banked human lung specimens from patients with ALI and lungs from mice with LPS-induced pneumonitis, we found that pulmonary SDF-1 expression increases during ALI. We further determined that both lung SDF-1 protein expression and mRNA expression rise in a delayed but sustained pattern in this mouse model and that the major source of the increase in expression appears to be the lung epithelium. Lastly, we found that expression of the SDF-1 receptor CXCR4 rises in a similar temporal pattern on neutrophils in both the blood and airspace of LPS-injured mice and that Ab-mediated SDF-1 blockade significantly attenuates late but not early pulmonary neutrophilia in this model. These results implicate SDF-1 in neutrophil recruitment to the lung in the later period of acute lung injury and suggest a novel role for this cytokine in coordinating the transition from the inflammatory response to the initiation of tissue repair.

Fibroblast foci are not discrete sites of lung injury or repair: the fibroblast reticulum.

BACKGROUND: Usual interstitial pneumonia (UIP), the pathologic correlate of idiopathic pulmonary fibrosis, contains characteristic discrete areas of fibroblasts, myofibroblasts, and newly formed collagen, termed "fibroblast foci." These lesions are argued to represent isolated sites of recurrent acute lung injury and suggested to be the mechanism of disease progression. We hypothesized that, rather than isolated, these lesions are part of an organized neoplasm. METHODS: Morphometric analysis of pentachrome-stained histologic sections of UIP was performed. Using point-counting technique on serial sections, fibroblast foci, arteries, and macrophage clusters were identified and we determined their individual "connectiveness" by estimating the Euler number. Two-dimensional micrographs were collated into a three-dimensional array from which a visual three-dimensional reconstruction could be constructed. Clonality analysis was performed using human androgen receptor gene methylation assay. RESULTS: Blood vessels show significant connectivity with a Euler number of 2, whereas macrophage clusters exhibited no connectivity. The fibroblast foci showed a high level of interconnection with Euler numbers ranging from 19 to 39. The computer generated three-dimensional models provide a visual confirmation of this connectiveness. Human androgen receptor gene methylation assay analysis of the foci showed balanced methylation consistent with polyclonality. CONCLUSIONS: The fibroblast foci of UIP are the leading edge of a complex reticulum that is highly interconnected and extends from the pleura into the underlying parenchyma. It is a reactive, rather than a malignant, process.

Laser-capture microdissection of plasma cells from subacute sclerosing panencephalitis brain reveals intrathecal disease-relevant antibodies.

Increased IgG and oligoclonal bands are found in cerebrospinal fluid of humans with chronic infectious CNS disease. Studies have shown that these oligoclonal bands are antibodies directed against the agent that causes disease. Laser-capture microdissection was used to isolate individual CD38+ plasma cells from the brain of a patient with subacute sclerosing panencephalitis, and single-cell RT-PCR was used to analyze individual IgG heavy and light chains expressed by each cell. Based on overrepresented IgG sequences, we constructed functional recombinant antibodies (recombinant IgGs) and determined their specificities. Five of eight recombinant IgGs recognized measles virus, the cause of subacute sclerosing panencephalitis. These results demonstrate that overrepresented IgG sequences in postmortem brains can be used to produce functional recombinant antibodies that recognize their target antigens. This strategy can be used to identify disease-relevant antigens in CNS inflammatory diseases of unknown etiology.

Analysis of nitric oxide synthase and nitrotyrosine expression in human pulmonary tuberculosis.

The role of nitric oxide (NO) in the host-defense against human tuberculosis (TB) is controversial. Although experimental evidence indicates that NO may play an important role in controlling TB, its expression in human tuberculous lungs has not been systematically characterized. We therefore investigated the expression of NO synthases (NOS) and of nitrotyrosine, the latter a marker of NO expression, in surgically resected lungs of eight patients with TB. Immunohistochemical and morphometric analyses revealed that, compared with control subjects, inducible NOS, endothelial NOS, and nitrotyrosine, but not neuronal NOS, were significantly elevated in the inflammatory zone of the tuberculous granulomas, and in the nongranulomatous pneumonitis zone. Tumor necrosis factor-alpha (TNF-alpha) was also significantly increased in tuberculous lungs and was principally localized to the necrotic, and to a lesser extent, the inflammatory and fibrotic areas of the granulomas. The NOS isoforms, nitrotyrosine, and TNF-alpha were expressed by the epithelioid macrophages and giant cells within the granulomas and in alveolar macrophages and epithelial cells in pneumonitis areas. This descriptive study provides evidence that in human TB, NOS isoenzymes and NO are present in specialized areas of the tuberculous granulomas; their precise role in human TB remains to be determined.