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.

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.

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.

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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.

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.

Increased IgG and oligoclonal bands (OGBs) are found in the cerebrospinal fluid (CSF) of humans with chronic infectious CNS diseases such as neurosyphilis, cryptococcal and tuberculous meningitis, Lyme disease, some viral meningitides, varicella zoster virus vasculopathy, and subacute sclerosing panencephalitis (SSPE), a chronic encephalitis caused by measles virus (MV). Studies in which the specificity of CSF OGBs was analyzed showed that the antibodies were directed against the agent that causes disease (1-8). For example, the OGBs in SSPE CSF and brain are antibodies directed against MV (1). These studies have led to the hypothesis that the oligoclonal IgG in the brain and CSF of patients with a chronic inflammatory CNS disease of unknown etiology, such as multiple sclerosis (MS), sarcoidosis, and Behcet's disease, is antibody directed against the agent that causes disease. Although OGBs are found in 88-100% of CSF from MS patients (9), the corresponding antigens remain unknown (10, 11). Such unanswered questions point to the need for improved techniques to identify disease-relevant antibodies and their cognate antigens and suggest the promise of such techniques in revealing the causes of inflammatory diseases with unknown etiologies.Here, we used laser-capture microdissection (LCM) to isolate individual CD38ϩ plasma cells from the brain of a patient with SSPE. Single-cell RT-PCR was used to amplify individual IgG heavy (H) and light (L) chain sequences expressed by each cell. Based on overrepresented Ig sequences, we constructed functional recombinant antibodies and identified their target antigens.Materials and Methods SSPE Brain. Brain removed from a 14-year-old male SSPE patient 5 h after death was flash-frozen and stored at Ϫ70°C. Sections (7 m) of frozen SSPE brain were prepared on nonplus glass slides (Fisher Scientific) at Ϫ30°C, fixed in acetone for 5 min at Ϫ20°C, and immunostained at 0°C for CD38ϩ cells. Briefly, sections were treated with 0.1% H 2 O 2 for 30 sec, incubated for 2 min with PBS containing 10% goat serum and then with a 1:50 dilution of mouse anti-human CD38 antibody (DakoCytomation, DAKO) for 10 min, rinsed in PBS, and incubated for 5 min with a 1:100 dilution of horseradish peroxidase-conjugated horse anti-mouse antibody (Vector Laboratories) and 5% goat serum in PBS. After rinsing in PBS, sections were incubated for 5 min with DAB substrate (Vector Laboratories), counterstained with hematoxylin, dehydrated in nuclease-free graded alcohols to 100% ethanol, and cleared with two rinses of H 2 0-free xylene. To preserve RNA, all aqueous solutions contained 200 units͞ml RNase inhibitor (Fisher Scientific), and the total time of tissue exposure to aqueous solutions was Ͻ25 min at 0°C. Staining was visualized by light microscopy.LCM and RT-PCR. LCM was performed on a PixCell IIe microscope (Arcturus Engineering, Mountain View, CA) with CapSure HS caps by using a pulse power of 70 mW, a 7.5-m laser spot diameter, pulse duration of 5 ms, and target voltage of 170 mV. Individual CD38ϩ cells ...

Ischemic heart disease (IHD) is the leading cause of death worldwide, and it is defined as an imbalance between myocardial oxygen supply and demand. Coronary artery disease (CAD) and left ventricular hypertrophy (LVH) are two common causes of IHD that independently result in myocardial ischemia. CAD decreases myocardial blood and oxygen supply whereas LVH increases myocardial oxygen demand. The coexistence of both CAD and LVH results in a significant increase in oxygen demand while simultaneously lowering oxygen supply.Since hypertension is a shared predisposing condition for both CAD and LVH, the left ventricular (LV) mass on noninvasive echocardiography can reflect on the severity of coronary artery stenosis. In clinical practice, it can help physicians decide whether to perform invasive cardiac catheterization to visualize the extent of the coronary block. Although, both CAD and LVH are directly proportional to mortality risk, the addition of eccentric LVH can further increase morbidity and mortality due to myocardial infarction. Therefore, the latest management of both the acute and chronic phases of CAD places an increased emphasis on controlling the predisposing factors to prevent or reverse LVH. For example, angiotensin-converting enzyme inhibitors and diuretics reduce LV mass by lowering the cardiac preload and afterload. This article aims to investigate the deleterious effects of the collaboration between CAD and LVH, establish a causal relationship, and explore the new prevention and management strategies.