Tonsillar crypt epithelium is an important extra-central nervous system site for viral replication in EV71 encephalomyelitis.

Enterovirus 71 (EV71; family Picornaviridae, species human Enterovirus A) usually causes hand, foot, and mouth disease, which may rarely be complicated by fatal encephalomyelitis. We investigated extra-central nervous system (extra-CNS) tissues capable of supporting EV71 infection and replication, and have correlated tissue infection with expression of putative viral entry receptors, scavenger receptor B2 (SCARB2), and P-selectin glycoprotein ligand-1 (PSGL-1). Formalin-fixed, paraffin-embedded CNS and extra-CNS tissues from seven autopsy cases were examined by IHC and in situ hybridization to evaluate viral antigens and RNA. Viral receptors were identified with IHC. In all seven cases, the CNS showed stereotypical distribution of inflammation and neuronal localization of viral antigens and RNA, confirming the clinical diagnosis of EV71 encephalomyelitis. In six cases in which tonsillar tissues were available, viral antigens and/or RNA were localized to squamous epithelium lining the tonsillar crypts. Tissues from the gastrointestinal tract, pancreas, mesenteric nodes, spleen, and skin were all negative for viral antigens/RNA. Our novel findings strongly suggest that tonsillar crypt squamous epithelium supports active viral replication and represents an important source of viral shedding that facilitates person-to-person transmission by both the fecal-oral or oral-oral routes. It may also be a portal for viral entry. A correlation between viral infection and SCARB2 expression appears to be more significant than for PSGL-1 expression.

Multiple organ infection and the pathogenesis of SARS.

After >8,000 infections and >700 deaths worldwide, the pathogenesis of the new infectious disease, severe acute respiratory syndrome (SARS), remains poorly understood. We investigated 18 autopsies of patients who had suspected SARS; 8 cases were confirmed as SARS. We evaluated white blood cells from 22 confirmed SARS patients at various stages of the disease. T lymphocyte counts in 65 confirmed and 35 misdiagnosed SARS cases also were analyzed retrospectively. SARS viral particles and genomic sequence were detected in a large number of circulating lymphocytes, monocytes, and lymphoid tissues, as well as in the epithelial cells of the respiratory tract, the mucosa of the intestine, the epithelium of the renal distal tubules, the neurons of the brain, and macrophages in different organs. SARS virus seemed to be capable of infecting multiple cell types in several organs; immune cells and pulmonary epithelium were identified as the main sites of injury. A comprehensive theory of pathogenesis is proposed for SARS with immune and lung damage as key features.

H5N1 infection of the respiratory tract and beyond: a molecular pathology study.

BACKGROUND: Human infection with avian influenza H5N1 is an emerging infectious disease characterised by respiratory symptoms and a high fatality rate. Previous studies have shown that the human infection with avian influenza H5N1 could also target organs apart from the lungs. METHODS: We studied post-mortem tissues of two adults (one man and one pregnant woman) infected with H5N1 influenza virus, and a fetus carried by the woman. In-situ hybridisation (with sense and antisense probes to haemagglutinin and nucleoprotein) and immunohistochemistry (with monoclonal antibodies to haemagglutinin and nucleoprotein) were done on selected tissues. Reverse-transcriptase (RT) PCR, real-time RT-PCR, strand-specific RT-PCR, and nucleic acid sequence-based amplification (NASBA) detection assays were also undertaken to detect viral RNA in organ tissue samples. FINDINGS: We detected viral genomic sequences and antigens in type II epithelial cells of the lungs, ciliated and non-ciliated epithelial cells of the trachea, T cells of the lymph node, neurons of the brain, and Hofbauer cells and cytotrophoblasts of the placenta. Viral genomic sequences (but no viral antigens) were detected in the intestinal mucosa. In the fetus, we found viral sequences and antigens in the lungs, circulating mononuclear cells, and macrophages of the liver. The presence of viral sequences in the organs and the fetus was also confirmed by RT-PCR, strand-specific RT-PCR, real-time RT-PCR, and NASBA. INTERPRETATION: In addition to the lungs, H5N1 influenza virus infects the trachea and disseminates to other organs including the brain. The virus could also be transmitted from mother to fetus across the placenta.

Assessment of diagnostic accuracy and feasibility of dynamic telepathology in China.

To assess the feasibility, including diagnostic accuracy and time cost, of a real-time telepathology system with pathologic slides, 600 cases covering a wide spectrum of lesions from 16 organ systems were tested. The "correct" diagnosis (gold standard) was established as a consensus by 2 experienced pathologists. The cases were first examined by 4 pathologists at different levels of experience with dynamic telepathology. Cases were then reviewed by the same pathologists using light microscopy in a blinded fashion 3 weeks to 2 months later. A diagnosis, together with reading times for telepathology and light microscopy, was recorded for each case. Diagnostic accuracy by telepathology was 94.8% (569/600), 93.3% (560/600), 91.6% (550/600), and 97% (388/400) for pathologists A, B, C, and D, respectively. Telepathologic diagnosis was concordant with the gold standard and with direct microscopy, with a mean of 94.2% and 99.26%, respectively. Most cases (510 or 85%) were diagnosed in 15 to 40 minutes by telepathology, with a mean of 17.0 minutes. The time needed to review a slide by telepathology was 3 to 4 times longer than that of standard light microscopy. All 4 pathologists were able to render a diagnosis in all cases. Our results showed that robotic telepathology is sufficiently accurate for primary diagnosis in surgical pathology, but modifications in laboratory protocols, telepathology hardware, and internet speed are needed to reduce the time necessary for diagnosis by telepathology before this method may be deemed suitable for use in a busy practice.

A feasibility study of virtual slides in surgical pathology in China.

China's huge territorial expanse and its imbalance of regional economic development have resulted in an uneven distribution of experienced pathologists. Developing telepathology for consultation is of special relevance to China. We developed a newly designed telepathology workstation, which includes a small file size of each slide, permitting easy transmission, storage, and manipulation, and a feedback function, and also evaluated its feasibility in surgical pathology in China. Four hundred cases covering a broad spectrum of surgical pathology problems were investigated in a blinded fashion by the 2 pathologists using this virtual microscope system. These cases were then randomized and re-reviewed a second time with light microscope. Diagnoses and time spent for each diagnosis were recorded for both methods. The diagnostic accuracies achieved by viewing glass slides and virtual images were 97.25% (389 of 400) and 95.5% (382 of 400) for pathologist A and 96.25% (385 of 400) and 94.75% (379 of 400) for pathologist B, respectively. There was no significant diagnostic discrepancy between the 2 methods for the 2 pathologists. The average times for viewing a virtual slide were 3.41 and 5.24 minutes for pathologists A and B, respectively, whereas the average times for viewing a glass slide were 1.16 and 3.35 minutes for pathologists A and B. There was a statistical difference between the time costs of the 2 methods. However, the slight time increase using virtual slides is less than that using dynamic telepathology and traditional consultation, and is acceptable to the pathologists. These results showed that this newly designed virtual microscope system have an acceptable diagnostic accuracy that is of practical value and may be suitable for application in China.

The spleen as a target in severe acute respiratory syndrome.

It has been proposed that immune injury is the central mechanism of pathogenesis of the infectious disease, severe acute respiratory syndrome (SARS). To gain a better understanding of immune injury in the spleen, we investigated the number and distribution of various immune cell types in the spleens of SARS patients. We performed autopsies on six confirmed SARS cases, with six normal subjects as controls; spleen samples from these autopsies were examined with hematoxylin and eosin (H&E) sections, in situ hybridization for SARS virus genomic sequences, and immunohistochemistry with seven monoclonal antibodies to five cell types. The number and distribution of these cells were measured and analyzed using an image analysis system. SARS genomic sequences were detected in all SARS spleens. The SARS spleens all had severe damage to the white pulp and showed an alteration of the normal distribution of various cell types. Immunocytes in the red pulp were decreased by 68.0-90.7% except for CD68+ macrophages and human leukocyte antigen (HLA)-DR positive antigen-presenting cells (APC), which were decreased to a lesser degree. On average, CD68+ macrophages were increased in size by 2.21-fold. We hypothesize that the collapse of the splenic immune system plays a key role in the clinical outcome of these patients.

Hydroa-like cutaneous T-cell lymphoma: a clinicopathologic and molecular genetic study of 16 pediatric cases from Peru.

Hydroa-like cutaneous T-cell lymphoma (hydroa-like CTCL) is an unusual pediatric malignancy with a poor prognosis. An impressive cutaneous rash characterized by edema, blisters, ulcers, crusts, and scars, resembling hidroa vacciniforme, is seen mainly on the face and sometimes on the extremities. The lesion consists of lymphomatous T-cell infiltration of the skin and subcutis with variable exocytosis and angiocentricity. It has been also called edematous, scarring vasculitic panniculitis and hydroa-like lymphoma. An association with Epstein-Barr virus has been suggested. The differential diagnosis includes other cutaneous lymphomas, particularly the cutaneous nasal type T/natural killer-cell lymphoma, mycosis fungoides, precursor T-cell lymphoblastic lymphoma, nonspecific peripheral T-cell lymphoma, cutaneous anaplastic large cell lymphoma, and subcutaneous panniculitic T-cell lymphoma. Other differential diagnoses are inflammatory dermatopathies and panniculitides. Based on a series of 16 such cases referred to the Institute of Neoplastic Diseases, the objective of this report is not only to provide a better clinicopathologic understanding of this entity but also a reappraisal of it as a malignancy. The male/female frequency ratio was 1:1. The median age was 10 years old. All cases showed predominant facial involvement with edema, blisters, ulcers, crusts, and scars. Chemotherapy and/or radiotherapy had little or no benefit. The prognosis was usually dismal. The lymphoma extended from the epidermis to the subcutis, with frequent angiocentric and periadnexal array. Lymphoma cells were mostly of intermediate size with dense hyperchromatic nuclei, inconspicuous nucleoli, and infrequent mitosis. A scanty and variable inflammatory background was found. The lymphoma cells displayed T-cell cytotoxic phenotype. In addition, they were negative for the natural killer cell antigens CD56 and CD57. Epstein-Barr virus in situ hybridization was positive in the six cases in which it was assayed. T-cell receptor gamma (TCRgamma) displayed monoclonal-type rearrangement in four cases studied. Our findings indicate that hydroa-like CTCL is an independent clinicopathologic entity that affects children. Consequently, it should be considered an independent subset of CTCLs and be included as such in the classification of neoplastic diseases of the lymphoid tissues.

National Institute on Drug Abuse Conference report on placental proteins, drug transport, and fetal development.

The use of illicit and licit drugs during pregnancy is a major public health concern because of potential adverse effects on the fetus and the risk to maternal health. Because the placenta is the primary link between the mother and the conceptus and is essential for the growth and survival of the fetus, abnormalities in placental formation and function resulting from drug use could have a major influence on pregnancy outcome. At present, little information is available on the impact of abused drugs on placental biology alone or in combination with other "host" factors (eg, stress, infections). This prompted the National Institute on Drug Abuse (NIDA) to convene a meeting of experts in placental biology to review cutting-edge research with the mission to translate existing information to new clinical and research initiatives in the drug abuse field. This report summarizes the presentations and research recommendations resulting from the workshop discussions.