Potential mechanisms for lung fibrosis associated with COVID-19 infection

Pulmonary fibrosis is a sequelae of Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) infection that currently lacks effective preventative or therapeutic measures. Post-viral lung fibrosis due to SARS-CoV-2 has been shown to be progressive on selected patients using imaging studies. Persistent infiltration of macrophages and monocytes, a main feature of SARS-CoV-2 pulmonary fibrosis, and long-lived circulating inflammatory monocytes might be driving factors promoting the profibrotic milieu in the lung. The upstream signal(s) that regulates the presence of these immune cells (despite complete viral clearance) remains to be explored. Current data indicate that much of the stimulating signals are localized in the lungs. However, an ongoing low-grade systemic inflammation in long Coronavirus Disease 2019 (COVID-19) symptoms suggests that certain non-pulmonary regulators such as epigenetic changes in hematopoietic stem cells might be critical to the chronic inflammatory response. Since nearly one-third of the world population have been infected, a timely understanding of the underlying pathogenesis leading to tissue remodeling is required. Herein, we review the potential pathogenic mechanisms driving lung fibrosis following SARS-CoV-2 infection based upon available studies and our preliminary findings (Graphical abstract).

Migration of wooden skewer foreign bodies from the gastrointestinal tract in eight dogs

Wooden skewer foreign bodies were found in eight dogs. Five presented for evaluation of draining sinuses and two for inflammatory disease referrable to the thorax, abdomen or pelvic region. In an additional case, pneumothorax resulted from perforation of the stomach and diaphragm. Ingestion was considered the most likely mode of access of the foreign body in all cases. Although the wooden foreign bodies were seen radiographically in only two dogs, identification of soft tissue or bony changes, or the results of contrast sinography assisted diagnosis. Surgical retrieval led to resolution of signs in all cases.

Hydrophobic extracts of a Chinese herb (CMX-13) exhibit potent immunosuppressive properties and prevent acute rejection in a highly histoincompatible model of rat lung transplantation

BACKGROUND

The potential of higher plants as sources for new immunosuppressive medications is well recognized. In our experiments we investigated the immunosuppressive effect of a highly refined and potent extract of a Chinese herbal preparation, CMX-13, on inhibiting acute allograft rejection (AR) in a highly histoincompatible rat lung transplant model, BN-->LEW, and on lymphocyte activation and cytokine gene expression in vitro.

METHODS

Left lung transplants: the control group (group 1) received only dimethylsulfoxide (DMSO) which is the solvent for CMX-13. Group 2 received intramuscular cyclosporin A (CsA, 25 mg/kg) on day 2 posttransplant. Group 3 and 4 received i.p. CMX-13 (0.5 mg/day, low dose and 5 mg/day, high dose, respectively) on day 1, 2, and 3 posttransplant. All animals were killed on day 6 posttransplant. Several pathological categories of inflammation were examined. In vitro experiments: rat spleen cells were incubated with Con A or irradiated stimulator cells with/without serial dilutions of CMX-13 or CsA. Cell proliferation was measured by 3H-thymidine incorporation. mRNA expression of interleukin-2 and interferon-gamma was examined by reverse transcriptase-polymerase chain reaction.

RESULTS

The severity of AR in animals receiving high dose CMX-13 was significantly reduced (stage II, P<0.05) compared with controls (stage IV). Significant differences were also seen when more specific parameters of inflammation were examined (necrosis, 0 vs. 1.7+/-1.0, P<0.05; interalveolar hemorrhage, 0 vs. 3.0+/-0.9, P<0.05). The responses seen in the animals treated with high dose CMX-13 were similar to those in the CsA group. CMX-13 inhibited T cell proliferative responses induced by Con A and alloantigen stimulation in a dose-dependent manner that were similar to CsA. Interleukin-2, and interferon-gamma mRNA expression in Con A-stimulated spleen cells was not inhibited by CMX-13 although CsA showed significant inhibition.

CONCLUSIONS

1) CMX-13 significantly reduces the stage of AR and parameters of inflammation in a highly histoincompatible rat lung transplant model. 2) CMX-13 has equal potency to CsA in the inhibition of Con A and alloantigen stimulated rat spleen cell proliferation. 3) CMX-13 showed no inhibitory effects on IL-2 and gamma-IFN mRNA expression, suggesting that its mechanism of action is different from CsA. 4) CMX-13 or derivatives may have potential utility as an immunosuppressive agent(s) in modulation of AR and management of other inflammatory and immunological disorders.

Partial molar transformation of the placenta of presumably monozygotic twins

A pregnancy with one normal female fetus and a placenta that was divided into halves, one normal the other molar, is described. Genetic analysis shows the molar component to be hyperdiploid/tetraploid but having an identical DNA composition as the normal twin. Because there was no trophoblastic proliferation and the hyperdiploid cells were confined to the villous stroma, and because the molar component was still being perfused by diploid vessels from the normal twin, we believe the mole is derived from polyploidization of the mesenchymal epiblast in a monozygotic twin pregnancy.

Prototype Web-based continuing medical education using FlashPix images

Continuing Medical Education (CME) is a requirement among practicing physicians to promote continuous enhancement of clinical knowledge to reflect new developments in medical care. Previous research has harnessed the Web to disseminate complete pathology CME case studies including history, images, diagnoses, and discussions to the medical community. Users submit real-time diagnoses and receive instantaneous feedback, eliminating the need for hard copies of case material and case evaluation forms. This project extends the Web-based CME paradigm with the incorporation of multi-resolution FlashPix images and an intuitive, interactive user interface. The FlashPix file format combines a high-resolution version of an image with a hierarchy of several lower resolution copies, providing real-time magnification via a single image file. The Web interface was designed specifically to simulate microscopic analysis, using the latest Javascript, Java and Common Gateway Interface tools. As the project progresses to the evaluation stage, it is hoped that this active learning format will provide a practical and efficacious environment for continuing medical education with additional application potential in classroom demonstrations, proficiency testing, and telepathology. Using Microsoft Internet Explorer 4.0 and above, the working prototype Web-based CME environment is accessible at http://telepathology.upmc.edu/WebInterface/NewInterface/welcome.html.

Prolongation of skin allograft survival is associated with reduced Th1 cytokine responses in the WKY-->F344 rat model

BACKGROUND

We have reported previously that F344 rats develop a spontaneous tolerance to WKY lung allografts and show long-term retention of donor-specific skin grafts placed 35 days after lung transplantation. In this study, we investigated the immunologic mechanisms that may be responsible for the prolonged skin graft survival in animals tolerized with lung allografts.

METHODS

In the rejection group, WKY skin grafts were placed on normal F344 rats, whereas, in the tolerance group, the skin grafts were placed on F344 rats that had received a WKY lung transplant 35 days before skin grafting. Th1 (interleukin [IL]-2 and interferon-gamma [IFN-gamma]) and Th2 (IL-4 and IL-10) cytokine as well as transforming growth factor-beta1 mRNA expression in skin grafts and in draining lymph nodes were determined by reverse transcription-polymerase chain reaction. Macrophage and lymphocyte infiltration in skin grafts and the number of Langerhans cells in epidermal sheets of the grafts were examined by immunohistochemistry.

RESULTS

IL-2 and IFN-gamma mRNA expression was significantly decreased in both the skin grafts and the draining lymph nodes of the tolerance group, compared to the rejection group, whereas IL-10 and transforming growth factor-beta1 mRNA expression was similar in both groups and IL-4 mRNA was rarely detected. Decreased and delayed CD8+, macrophage, and natural killer cell infiltration in the skin grafts from the tolerance group was also detected. Similar reduction in the number of Langerhans cells in the epidermis of the grafts from both groups was seen on day 1 after skin grafting, and thereafter the number remained stable in both groups.

CONCLUSIONS

Reduced expression of Th1 cytokines and decreased infiltration of CD8+ cells, macrophages, and natural killer cells in the skin grafts may be responsible for prolongation of skin graft survival in the tolerance group.

Estimation of tumor stage and lymph node status in patients with colorectal adenocarcinoma using probabilistic neural networks and logistic regression

Staging colorectal adenocarcinoma on the basis of biopsy specimens could identify patients who might benefit from neoadjuvant therapy without undergoing resection first. In this study, we evaluated the ability of artificial neural networks with genetic algorithms and multivariate logistic regression to predict the stage of 99 patients with primary colorectal adenocarcinoma by analyzing age, tumor grade, and immunoreactivity to p53 and bcl-2 with use of endoscopically obtained biopsy specimens. We correlated results with regional lymph node status and tumor stage, identified in subsequent colectomy specimens. bcl-2 and p53 protein expression were demonstrated by immunohistochemical methods, using formalin-fixed, paraffin-embedded biopsy tissues. Tumor grade was evaluated in hematoxylinand eosin-stained sections. Patients were divided into training (n = 75) and testing cases (n = 24). Several probabilistic neural networks with genetic algorithm models were trained, using the four prognostic features as input neurons and regional lymph node status or stage as output neurons. Data were analyzed with univariate statistics and multivariate logistic regression. The cases were divided into training (n = 40) and testing (n = 59). The best two models classified correctly the lymph node status of 20 of 24 test patients (specificity, 80%; sensitivity, 85%; positive predictive value, 86%) and the tumor stage of 21 of 24 test patients (specificity, 82%; sensitivity, 92%; positive predictive value, 85%), respectively. Tumor grade and p53 protein were statistically significant (P < .05) by analysis of variance for lymph node status and tumor stage. Logistic regression models with these two independent variables correctly estimated the probability of lymph node metastases in 44 of 59 test cases and the tumor stage of 43 of 59 test cases, respectively. Results indicated the usefulness of probabilistic neural networks in the population studied, but the findings should be validated with large groups of patients.

"Refractoriness" of airflow obstruction associated with isolated lymphocytic bronchiolitis/bronchitis in pulmonary allografts

The clinical significance of an isolated "lymphocytic bronchiolitis/bronchitis" (grade B) as detected in transbronchoscopic biopsy specimens (TBB) is unclear. We therefore have reviewed the spirometric responses associated with isolated grade B diagnoses and contrasted them with episodes of "acute cellular rejection" (grade A); the latter are manifested by "perivascular lymphocytic infiltration." Because lymphocytic bronchiolitis/ bronchitis is considered a nonspecific histologic pattern that may be observed with either allograft rejection or respiratory infections, episodes were analyzed with respect to the presence (grade B [+] CMV) or absence (grade B [-] CMV) of cytomegalovirus infection. The maximum forced expiratory volume in 1 second (FEV1) during the preceding 3 months was used as a baseline for computing percent change in FEV1 coincident with transbronchoscopic biopsies (delta %FEV1 PRE) and maximum values obtained during the 3 months subsequent to specific therapies (delta %FEV1 POST). All episodes of acute cellular rejection (grades A1 to 4) and symptomatic lymphocytic bronchiolitis/bronchitis (grade B) were treated with "pulsed-dose" methylprednisolone, whereas intravenous ganciclovir was administered to patients at risk for recrudescence of cytomegalovirus. Between March 1, 1989, and September 1, 1995, 366 TBB procedures were performed for clinical indications in 57 lung transplant recipients. Histologic diagnoses with acceptable serial spirometric values included grade A1 (n = 9), grade A2 (n = 27), grade A3 (n = 2), grade B(-)CMV (n = 25) and grade B(+)CMV (n = 9). The delta %FEV1 PRE coincident with TBB were not statistically different for the different histologic groups. For grade A1, delta %FEV1 PRE was -14.6% +/- 5.2% (X +/- SEM); A2, -7.6% +/- 1.8%; B(-)CMV, -14.8% +/- 3.9%; and B(+)CMV, -14.8% +/- 2.3%. After treatment, the delta %FEV1 POST, relative to baseline values, were for grade A1, -8.8% +/- 7.1%, A2, +0.26% +/- 2.6%; B(-)CMV, -12.0% +/- 3.8%; and B(+)CMV, -6.2% +/- 2.8%. The delta %FEV1 POST values after pulsed methylprednisolone were significantly greater for histologic grade A2 than grade B(-)CMV (unpaired Student's t test, P < 0.01; 95% confidence interval for the difference of means: 3.34% to 21.2%). Grade A2 rejection was associated with spirometric improvement to within 10% of baseline values in 52% of episodes; whereas with grade B(-)CMV, this salutary response was observed in only 32% of episodes. Bronchiolitis obliterans syndrome stage 1b developed in 13 of 20 (65%) recipients, approximately 7.9 +/- 3.4 months after detection of histologic grade B and 21.2 +/- 9.5 months after transplantation. We conclude that the relative "refractoriness" of histologic grade B most likely reflects a continuum of bronchiolitis obliterans after lung transplantation and, hence, may warrant different immunosuppressive strategies. Furthermore, spirometric decrement associated with acute cellular rejection (grade A) may be ameliorated, but often not completely reversed, after pulsed methylprednisolone. We speculate that surveillance TBB may prove rewarding by enabling an earlier detection of these histologic diagnoses before the development of physiologic impairment.

Upper airway obstruction secondary to acinic cell carcinoma of the trachea. Use of Nd:YAG laser

Comprising 1 to 4% of all tumors and 7 to 15% of malignant neoplasms of the major salivary glands, acinic cell carcinoma (ACC) rarely occurs in the respiratory tract. There has been only one case of ACC of the trachea previously reported in the medical literature. A second case of ACC of the trachea associated with upper airway obstruction and its management by Nd: YAG laser and surgical resection is reported.

Quality assurance issues in DNA image cytometry

DNA image cytometry is currently used in many clinical laboratories as a prognostic tool for the study of patients with malignant neoplasms. However, quality assurance (QA) procedures for image cytometry (IC) have not been standardized. National proficiency testing programs for DNA IC are yet to be developed. We describe our QA program for DNA IC. Indicators of quality; thresholds for evaluation; methods for collection, organization, and evaluation of data; and actions recommended to deal with problems are described for each of the phases of DNA IC. They include QA procedures for sample acceptability; staining technique; instrumentation, including linearity and calibration verification; and correlation with other cytometric methods. The difficult problem of standardizing the postanalytical phase of QA is discussed. The need for a consensus conference to adopt standardized QA procedures for DNA image analysis is emphasized.

Revision of the 1990 working formulation for the classification of pulmonary allograft rejection: Lung Rejection Study Group

In 1990, an international grading scheme for the grading of pulmonary allograft rejection was instituted. The use of this classification has resulted in a uniformity of grading which has allowed inter-institutional collaborations and communication unique in allograft monitoring. In 1995 an expanded group of international pathologists convened and revised the original proposal. This article summarizes the updated classification for pulmonary allograft rejection. In brief, acute rejection is based on perivascular and interstitial mononuclear infiltrates. Each grade of acute rejection should mention the presence of coexistent airway inflammation, the intensity of which may also be graded. Chronic rejection is divided into bronchiolitis obliterans--active or inactive--and vascular atherosclerosis--accelerated arterial or venous sclerosis.

Assessment of pathological changes associated with chronic allograft rejection and tolerance in two experimental models of rat lung transplantation

Lung transplantation is now routinely performed for a wide range of end-stage cardiopulmonary disorders. Despite overcoming the problems associated with early acute rejection, chronic rejection (CR) in the form of obliterative bronchiolitis has emerged as the primary cause of late graft loss. The mechanisms involved in the development of CR of lung allografts are poorly understood, and no effective therapy is currently available. To better understand the pathological events associated with CR and tolerance, we examined two models of lung allograft rejection established in our laboratory. First, we exchanged left lung allografts between moderately histoincompatible inbred rat strains (WKY-->F344: n = 42 and F344-->WKY: n = 40). The WKY-->F344 model was previously shown to develop spontaneous tolerance, while the converse model (F344-->WKY) showed persistent acute rejection. The purpose of this investigation was to assess histopathological changes associated with long-term grafts left in place up to 140 days after transplant. To confirm that tolerance had developed, skin-grafting experiments were performed. Five skin grafts from each strain were placed on lung allograft recipients on day 35 after transplant and skin allograft survival was assessed and compared with controls. Acute rejection (AR) was graded histologically (stage O-IV) and the pathologic intensity of inflammation and CR were graded (0-4: 0 = 0%, 1 = 1-25%, 2 = 26-50%, 3 = 51-75%, and 4 = 76-100%) on percentage of involvement with the following categories being examined: (a) lymphocytic infiltration (perivascular, peribronchial, and peribronchiolar) and (b) vasculitis, edema, hemorrhage, and necrosis. Finally, chronic rejection was diagnosed by the presence of intimal hyperplasia, interstitial fibrosis, peribronchiolar fibrosis, bronchiolitis obliterans, and bronchiectasis. The WKY-->F344 animals showed progressive AR (stage III, day 21). Thereafter, the AR subsided spontaneously and was stage 0 on day 140. There were no signs of CR in these animals. In the F344-->WKY model, the AR progressed up to stage III-IV (day 21) and maintained for several weeks at stage III. Thereafter, pictures of the lungs showed CR on days 49, 70, and 98. There were significant differences between the two models during the chronic phase, such as interstitial fibrosis (0 +/- 0 vs. 1.8 +/- 1.3, P < 0.005), peribronchiolar fibrosis (0 +/- 0 vs. 3.6 +/- 0.55, P < 0.01), vasculitis (0.2 +/- 0.45 vs. 2.0 +/- 0, P < 0.008), and intimal hyperplasia (0.2 +/- 0.45 vs. 2.6 +/- 0.9, P < 0.008).(ABSTRACT TRUNCATED AT 250 WORDS)

Soluble CTLA4Ig modifies parameters of acute inflammation in rat lung allograft rejection without altering lymphocytic infiltration or transcription of key cytokines

The efficacy of CTLA4Ig in blocking immune activation and allograft rejection (AR) was tested in an aggressive and rapid model of rat lung AR (Brown Norway [BN]-->Lewis [LEW]). CTLA4Ig is a recombinant soluble protein that binds with high affinity to rat B7/BB1 and other surface molecules on APCs, subsequently blocking the binding of B7/BB1 to CD28/CTLA4 on T cells. This interrupts the costimulatory pathway critical for complete T cell activation and completion of the AR process. Left single-lung transplants were performed between BN-->Lew. Five allograft recipients were examined in each group. At transplantation, animals received 250 micrograms of CTLA4Ig or 250 micrograms of control Ig intraperitoneally daily until sacrifice. Animals were sacrificed on days 2, 4, and 7 after transplant. Control (BN-->Lew) grafts show irreversible rejection by day 7. Syngeneic (Lew-->Lew) grafts show no AR on day 7. AR episodes were graded histologically (stages 0-IV) and pathologic intensity of inflammation was graded on percentage of involvement. Cytokine transcript levels were measured in control and CTLA4Ig-treated animals (n = 5 in each group) on day 7 using reverse transcriptase polymerase chain reaction techniques. The most profound differences were found on day 7 after transplant. The degree of lymphocytic infiltration was greater in the CTLA4Ig group (perivascular: 4 +/- 0 vs. 2.6 +/- 0.6, peribronchial: 4 +/- 0 vs. 2.2 +/- 0.4, and peribronchiolar: 3.6 +/- 0.5 vs. 2 +/- 0.3, P < 0.01). However, in striking contrast, the stage of AR (3 +/- 0 vs. 4 +/- 0, P < 0.01), vasculitis (1 +/- 0.7 vs. 2.6 +/- 0.6, P < 0.05), hemorrhage (0.4 +/- 0.6 vs. 3.2 +/- 0.4, P < 0.01), and necrosis (0 +/- 0 vs. 2.4 +/- 0.5, P < 0.005) were significantly reduced in animals treated with CTLA4Ig. Since CTLA4Ig blocks Th1 cell activation in vitro, we compared the levels of Th1 inflammatory cytokines IL-2, gamma-IFN, and TNF-alpha in the two models. The intragraft ratios (CTLA4Ig/control) were IL-2:0.77, gamma-IFN: 1.29, and TNF-alpha:1.33. Thus, CTLA4Ig did not significantly block intragraft production of Th1 cytokines on day 7.(ABSTRACT TRUNCATED AT 400 WORDS)

Neural networks as an aid in the diagnosis of lymphocyte-rich effusions

Neural network (NN) technology was applied to digital image analysis data for 112 Papanicolaou-fixed and -stained smears of lymphocyte-rich effusions (LREs). The smears were analyzed with an inexpensive image analysis system assembled in our laboratory. Several models were developed using backpropagation NN development software in an effort to optimize classification of the LREs as reactive lymphocytosis or malignant lymphoma and to analyze the effects of various parameters on classification rates. The greatest specificity and sensitivity of LRE classification were achieved with NN models that consisted of 7 input neurons, including 5 morphometric and 2 densitometric variables, 10 hidden-layer neurons and 1 output neuron. This NN architecture with a sigmoidal transfer function provided a true cross-validation rate of 89.3% of testing data, with a sensitivity of 76.9%, specificity of 93.0% and shrinkage of 10.7%. The same NN architecture with a step transfer function provided a true cross-validation rate of 95.3%, sensitivity of 85.7%, specificity of 97.6% and shrinkage of 0%. The effects of various parameters, such as network size, shrinkage and ratio of sample size to input layer size, on NN accuracy are discussed.

Differential soluble interleukin-2R levels in bilateral bronchoalveolar lavage after single lung transplantation

Preliminary reports suggest that measurement of the soluble 55 kd subunit of the interleukin-2 receptor may facilitate the diagnosis of allograft rejection in solid organ transplants. Levels of soluble interleukin-2 receptor in serum or plasma have previously lacked sufficient sensitivity and specificity for the diagnosis of acute allograft rejection. Because single lung transplantation is preferentially performed for nonseptic end-stage pulmonary and cardiopulmonary maladies, we questioned whether the pattern of soluble interleukin-2 receptor recovery in bronchoalveolar lavage fluid obtained from both the native and transplanted lungs may enhance correct diagnosis. Fifty-three consecutive fiberoptic bronchoscopic procedures were performed with bilateral bronchoalveolar lavage fluid. Transbronchoscopic biopsies were histologically classified by the International Society for Heart Transplantation Working Formulation for Standardized Nomenclature. "Soluble interleukin-2 receptor index" was calculated as the quotient of soluble interleukin-2 receptor (in units per milliliter) by enzyme-linked immunosorbent assay, divided by protein (in milligrams per milliliter) to correct for differences in bronchoalveolar lavage fluid techniques and cellularity. Soluble interleukin-2 receptor indexes were significantly increased in the allograft bronchoalveolar lavage fluid during histologic grade A (acute rejection) versus normal transbronchoscopic biopsy specimens (3395 +/- 1298 U/mg versus 76 +/- 21 U/mg) associated with an increased transplanted/native lung ratio (69.9 +/- 46 versus 2 +/- 1 [mean +/- standard error of the mean]) (one-way analysis of variance, p < 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)

Detection of Epstein-Barr virus by polymerase chain reaction in transbronchial biopsies of lung transplant recipients: evidence of infection?

Thirty-nine paraffin-embedded transbronchial biopsies from ten lung transplant recipients were evaluated by the polymerase chain reaction for the presence of Epstein-Barr virus (EBV). Six of these patients had positive EBV serology. Nine biopsies from nine non-transplant patients with nonspecific interstitial pneumonitis were studied as a control group. Eight biopsies from four of the ten transplant patients (40%) were positive for EBV by polymerase chain reaction, utilizing 40 cycles and two sets of primers (501/502) complementary to sequences within the Bam H1 W region of the viral genome. Five of these eight positive biopsies had been diagnosed as mild acute cellular rejection based on clinicopathologic criteria. Three of the four EBV-positive patients showed clinical improvement with antiviral agents prescribed for concomitant cytomegalovirus infection. Our data demonstrate the potential of polymerase chain reaction to detect small quantities of EBV in transbronchial biopsies from lung transplant recipients. Such findings should be interpreted cautiously in the evaluation of lung transplant recipients, since EBV can be detected in the absence of a lymphoproliferative disorder or an active pneumonitis caused by this virus.

Lung transplantation: the pathologic diagnosis of pulmonary complications

The reliability of bronchoscopy with transbronchial biopsies for the diagnosis of acute graft rejection has recently been questioned. We present our experience with 59 transbronchial and bronchial biopsies and two open-lung biopsies from 12 patients that underwent lung transplantation. The diagnosis of acute rejection was established in 14 biopsies based on the absence of infection and presence of one or more of the following features: perivascular lymphoid infiltrates, usually associated with endothelial swelling; bronchial "acute on chronic" inflammation; and/or angiitis. Problems and potential pitfalls in the diagnosis of acute graft rejection in lung transplant patients are discussed. The biopsies were also sensitive for the diagnosis of cytomegalovirus pneumonitis and fungal infections but were not helpful for the diagnosis of bacterial pneumonias. Indeed, one patient died with Legionella sp. pneumonia diagnosed only on open-lung biopsy after two negative transbronchial biopsies. The significance of other histologic changes, such as nonspecific interstitial pneumonitis, diffuse alveolar damage, acute alveolitis, goblet cell hyperplasia of the bronchial mucosa, and pulmonary infarction, is discussed.

Epithelioid angiomatosis or cat scratch disease with splenic and hepatic abnormalities in AIDS: case report and review of the literature

Cat scratch disease (CSD) in the setting of HIV infection is associated with lesions of epithelioid angiomatosis but not with granulomatous lesions seen in the normal host. We report a case of CSD in a patient with AIDS and Kaposi's sarcoma with epithelioid angioma of skin, thrombocytopenia, and abnormalities of liver, spleen, lymph node, and pleura that responded to antimicrobial therapy. We also review reported cases of epithelioid angiomatosis in HIV infections. 12 of these resolved, including 3 without antimicrobial therapy; 18 demonstrated pleomorphic organisms with Warthin-Starry silver stain. Six involved visceral or bony as well as skin lesions. CSD should be considered in the setting of HIV infection with skin nodules even in the presence of biopsy-proven Kaposi's sarcoma. CSD may in these patients be responsible for a variety of disseminated lesions which respond to antimicrobial therapy.

Lymphocytic interstitial pneumonia in patients at risk for the acquired immune deficiency syndrome

Three patients with the acquired immune deficiency syndrome (AIDS) or AIDS-related complex and lymphocytic interstitial pneumonia are reported. All patients presented with progressive dyspnea, nonproductive cough, fever, anorexia, weight loss, and arterial hypoxemia. Chest roentgenograms exhibited bilateral diffuse reticular-nodular densities. The diagnosis of lymphocytic interstitial pneumonia was made by fiberoptic bronchoscopy or open lung biopsy. Two patients were treated with corticosteroids, with significant improvement. The third patient died of pneumonia due to Pneumocystis carinii six months after the diagnosis of lymphocytic interstitial pneumonia was established. Serum antibodies to human immunodeficiency virus (HIV) were demonstrable in the two patients in whom the test was performed. Lymphocytic interstitial pneumonia is probably another pulmonary manifestation of AIDS or AIDS-related complex. Although the clinical presentation may be identical to the more common opportunistic infections, the treatment differs, and the prognosis may be better.

Endometrial cyst of the liver

A 21-yr-old woman with a history of epigastric pain and a right upper quadrant mass was found to have a large parenchymal hepatic cyst on CT scan. The cyst was removed at surgery and found to be lined by ectopic endometrial tissue. This is, to our knowledge, the first recorded instance of endometriosis of the liver. The clinicopathological features of this patient and the possible pathogenesis of her most unusual hepatic lesion are discussed.

Primary lymphoma of the liver in the acquired immunodeficiency syndrome

We describe a 78-year-old man with a diffuse large-cell lymphoma that was limited to the liver and was associated with micronodular cirrhosis and Kaposi's sarcoma that involved abdominal lymph nodes and gastric mucosa. The serum of the patient reacted positively to a test for human T-cell lymphotropic virus type III antibodies. We discuss the clinical and autopsy findings for this unusual patient, the criteria for the diagnosis of primary lymphoma of the liver, and its occurrence in patients with the acquired immunodeficiency syndrome.

Computerized interactive morphometry as a potentially useful tool for the classification of non-Hodgkin's lymphomas

The use of a simple form of Computerized Interactive Morphometry (CIM) is proposed as a tool to achieve a reproducible classification of non-Hodgkin's lymphomas. This system combines a random sampling method for cells with simple size measurements and additional subjective criteria such as a shape, mitotic counts, and follicular or diffuse features. In this system, which utilizes a high resolution touch screen as interactive peripheral, the video image of the specimen is superimposed to a computer generated reference system which consists of a test area and four fixed points for random sampling of cells and a series of concentric circles to serve as internal standard for nuclear size; the computer tabulates and facilitates data processing. Forty-four lymphoid lesions have been characterized with the CIM system and specific criteria for diagnoses according to the Working Formulation of non-Hodgkin's lymphomas for clinical usage are derived. Studies of inter- and intraobserver variations in data collection are discussed, and a diagnostic algorithm that categorizes non-Hodgkin's lymphomas according to the relative proportions of various lymphoid cells and densities of mitotic counts is proposed. The potential applications of touch screen-based CIM for the study of malignant lymphomas and its practical technical advantages over other quantitative systems based on either gray-level analysis or tracings of cell contours on photographs or digitizer pads are emphasized.

Mixed tumor of the mediastinum

A 36-year-old asymptomatic man was found to have a large middle mediastinal mass on a chest x-ray film. At surgery the tumor was located adjacent to the carina and beneath the aortic arch. It measured 7.0 X 5.0 X 4.0 cm and was well circumscribed and soft, with mucoid areas. The histologic features were those of a benign pleomorphic adenoma of salivary gland origin. This is, to our knowledge, the first reported case of primary pleomorphic adenoma of the mediastinum. We propose an origin from the ectopic salivary gland tissue. We also describe an additional patient in whom ectopic benign salivary gland tissue was found within mediastinal lymph nodes to support our hypothesis.

Diagnosis of pulmonary complications of the acquired immune deficiency syndrome

Forty eight patients with the acquired immunedeficiency syndrome (AIDS) presented to the Mount Sinai Hospital in New York with persistent cough and dyspnoea or an abnormal chest radiograph, or both. Thirty two (67%) were found to have Pneumocystis carinii pneumonia, either alone or in combination with another pathogen. Of these patients, eight (25%) had a normal chest radiograph. Abnormalities in the single breath carbon monoxide diffusing capacity and alveolar-arterial oxygen gradient [A-a) DO2) suggested infection with Pneumocystis carinii. Fibreoptic bronchoscopy with transbronchial biopsy was 100% sensitive in the diagnosis of pneumocytis pneumonia. Fibreoptic bronchoscopy should be undertaken in patients suspected of having a pulmonary complication of AIDS, even if the chest radiograph is normal.

Pulmonary complications of the acquired immunodeficiency syndrome: a clinicopathologic study of 70 cases

The pulmonary complications of 70 patients with the acquired immunodeficiency syndrome (AIDS) are reviewed. Pneumocystis carinii pneumonia (PCP), present in 67 per cent of the patients, was diagnosed by fiberoptic bronchoscopy with transbronchial biopsies in all of the patients except two adults, who required open lung biopsy, and two children, in whom the infection was detected only at autopsy. Other opportunistic infections, such as cytomegalovirus pneumonitis, mycobacterial infections, invasive candidiasis, toxoplasmosis, cryptococcosis, and histoplasmosis, were more difficult to diagnose by fiberoptic bronchoscopy. In only four cases were these conditions detected during life. Neoplasms and lymphoproliferative processes also presented diagnostic problems, and only one case each of Kaposi's sarcoma and lymphoid interstitial pneumonitis were detected by fiberoptic bronchoscopy. In four other cases these conditions, as well as two pulmonary lymphomas, diffuse large cell immunoblastic type, were detected only at autopsy. Sixty-eight per cent of the patients in this study died, usually with progressive intractable respiratory failure and pulmonary complications that had not been diagnosed during life, including potentially treatable diseases, such as bacterial pneumonias, PCP, nontuberculous mycobacteria, invasive candidiasis, toxoplasmosis, and invasive aspergillosis. The need for earlier detection of pulmonary complications in patients with AIDS is discussed.

Nontuberculous mycobacteria in pleural fluid. Assessment of clinical significance

We reviewed the case records of 22 patients from whose pleural fluid a nontuberculous Mycobacterium (NTM) was isolated. Three patients had pleural effusions definitely due to NTM infection, with evidence of NTM infection in other tissues; 16 had pleural effusions of known etiology unrelated to the isolated NTM and no other evidence of NTM infection; and three had pleural effusions of undetermined etiology and no other evidence of NTM infection. The case histories of the three patients with pleural effusions due to NTM are presented and the significance of the isolation of NTM from the remaining 19 patients is discussed. Criteria are proposed for evaluating the significance of NTM isolated from pleural fluid.

Diagnosis of lung cancer by fibreoptic bronchoscopy: problems in the histological classification of non-small cell carcinomas

Specific cell typing in lung cancer has important implications for assessment of prognosis and the planning of treatment. Cell typing is, however, often difficult and the problem has been compounded by the universal use of the flexible fibreoptic bronchoscope, which yields specimens only 2 mm in diameter. We have reviewed the records of 107 patients who had a diagnosis of lung cancer established by fibreoptic bronchoscopy and who subsequently underwent staging biopsy or surgical resection. Examination of tissue obtained by surgical resection yielded a different cell type from that identified in specimens obtained at fibreoptic bronchoscopy in 11 of 32 patients with a bronchial biopsy specimen diagnostic of squamous cell, three of 44 patients with a diagnosis of adenocarcinoma, six of seven thought to have a poorly differentiated carcinoma, and 21 of 24 patients with a diagnosis of large cell carcinoma. In all, 41 of the 107 surgically removed specimens (38%) differed in cell type from their corresponding bronchoscopic specimens. Accurate cell typing by specimens obtained at fibreoptic bronchoscopy may be extremely difficult. If clearcut morphological criteria cannot be satisfied, the diagnosis of "lung cancer, non-small cell type" should be made.

Localized lymphoid nodules of lung. A reappraisal of the lymphoma versus pseudolymphoma dilemma

Eleven patients with localized lymphoid nodules of the lung (LLN) were seen at the Mount Sinai Hospital from 1962-1981. The diagnosis of pseudolymphoma was made in six instances based on the following criteria: (1) solitary or multiple nodules discovered on chest roentgenograms composed of cytologically benign lymphoid cells (small lymphocytes); (2) polymorphic character of the infiltrate, including plasma cells, histiocytes and monocytes; and (3) presence of germinal centers in the lesion. Five lesions were classified as lymphomas and exhibited: (1) solitary or multiple nodules composed of atypical lymphoid cells; (2) absence of germinal centers; (3) lack of mediastinal lymph node involvement. Bronchial and/or pleural infiltration by lymphoid cells was present in lymphomas as well as in pseudolymphomas. Five lesions were studied with immunofluorescent techniques for the presence of intracytoplasmic immunoglobulins and in one pseudolymphoma, lymphocyte marker studies were performed. The procedures were not useful in separating benign from malignant lesions. All patients underwent surgery; three with lymphoma and one with pseudolymphoma received adjuvant chemotherapy. Patients were followed post surgically for up to 13 years. None of the six patients with pseudolymphoma died as a result of their lesions but two had either recurrences or developed extrapulmonary lymphoid lesions. All five lymphoma patients did well. Only one died while on chemotherapy with invasive pulmonary aspergillosis but no tumor. One-hundred and sixty-seven reported cases from the literature are analyzed. Pulmonary pseudolymphomas do not necessarily follow a benign course and malignant lymphomas limited to the lungs do not usually undergo progressive disease. Present pathologic criteria do not allow prediction of recurrence or progression of disease and are not acceptable for determining the advocacy of chemotherapy in patients with LLN.

The spectrum of pathology of nontuberculous mycobacterial infections in open-lung biopsy specimens

The diagnosis of pulmonary nontuberculous mycobacterial (NTM) infection may be difficult to establish unless open-lung biopsy is performed. Mycobacteria were present in resected lung tissues from forty patients at the Mount Sinai Hospital during the period 1969-1980. M. avium-intracellulare was cultured in 24 patients, M. tuberculosis in six, M. gordonae in three, and M. fortuitum in two. In five instances, mycobacteria were seen in smears of lung tissues but failed to grow in culture. Three distinct clinicopathologic groups of patients with NTM were recognized. (1) Eighteen patients had solitary pulmonary nodules resected with the clinical diagnosis of lung cancer. Histologically, they exhibited granulomas with varying degrees of necrosis. Mediastinal lymph nodes had no granulomas, except in one case. (2) Seven patients presented with roentgenologic evidence of bilateral, diffuse interstitial infiltration. M. avium-intracellulare or M. gordonae were isolated from lung tissue which histologically showed interstitial fibrosis and organizing pneumonia. In only one instance a few non-caseating epitheloid cell granulomas were found. Three of these patients had underlying malignancies treated with chemotherapy and one other had arthritis. The other three had no underlying diseases. (3) Three patients had multiple discrete infiltrates on chest roentgenograms. M. avium-intracellulare was isolated from their lung tissues. One of these patients exhibited necrotizing granulomatous vasculitis indistinguishable from Wegener's granulomatosis. It is apparent that classical "tuberculosis-like" granulomatous reaction is the most common histologic pattern but should not be expected in all patients with NTM infections.

Quantitative studies of argyrophilic APUD cells in airways: II. The effects of transplacental diethylnitrosamine

The effects of transplacental administration of diethylnitrosamine (DEN) on the densities of epithelial and APUD cells in the large and small airways of developing hamsters have been studied quantitatively. The APUD cells are quantitated by relating them to the number of airway epithelial cells; APUD cells are present in similar densities in the large airways (0.12 APUD cells/100 cells) and small airways (0.14) of 2-day-old control hamsters. At 4 days an increase in the densities of APUD cells and an increase in epithelial cells is observed in the small airways, whereas those in the large airways decrease slightly. At later periods there is a progressive decline in the density of APUD cells in the control hamsters. Exposure in utero to DEN results in a generalized increase in APUD cells in 2-day-old hamsters, which is more pronounced in bronchioles (fivefold increase). The effect disappears in older animals. It also results in a transient increase in tracheal epithelial cell density in 7-day-old hamsters. Whether the selective and transient APUD cell hyperplasia induced by transplacental administration of DEN results from proliferation of these cells or from differentiation of other types of epithelial cells into APUD cells requires further study.

Pulmonary tumorlets in cases of "tuberculoma" of the lung with malignant cells in brush biopsy

Two cases of pulmonary nodules associated with Mycobacterium intracellulare infection were initially interpreted as carcinomas of the lung after brush cytology specimens were reported to contain malignant epithelial cells. In both instances, the cells observed in the cytology specimens exhibited marked cytologic atypia. These cells were identical to those present in tumorlets adjacent to the granulomatous lesion. Tumorlets may thus represent a source of false-positive cytologic findings or constitute a type of microscopic neoplasms of the lung.