Mac 387 antibody and detection of formalin resistant myelomonocytic L1 antigen

Intraoperative tissue sampling for histology in chronic osteomyelitis shows high neutrophil infiltration centrally and low remains in debrided presumed infection-free regions

INTRODUCTION

Histology of debrided bone tissue is a confirmatory diagnostic criterion for fracture related infection (FRI) and prosthetic joint infection (PJI). The aim of the present study was to describe the histopathology of the first and last debrided bone tissue in chronic osteomyelitis (CO) according to the international diagnostic guidelines for FRI and PJI.

METHODS

15 patients with CO were allocated to surgical treatment using a one-stage protocol including extensive debridement. Suspected infected bone tissue eradicated early in the debridement procedure was collected as a clearly infected sample (S1). Likewise, the last eradicated bone tissue was collected as a suspected non-infected sample (S2). The samples were processed for histology. HE-stained sections were patho-morphologically examinated. Immunohistochemistry with MAC-387 antibodies towards calprotectin was used for estimation of neutrophil granulocyte (NP) score (0, 1, 2 or 3).

RESULTS

S1 samples showed a mean NP score of 2.6 (3 is confirmatory for infection). Following debridement, the NP score was significantly (p = 0.005) reduced to a mean NP score of 1.6. The S1 samples showed a mix of fibrovascular tissue, dense fibrosis, viable bone, bone necrosis and bone debris. S2 samples contained mostly viable bone tissue, however, often small fragments of necrotic bone or bone debris were present.

CONCLUSION

The inflammatory response of CO still exists after debridement, although the response fades from the center. Therefore, sampling of debrided bone tissue for histology must be performed initially during surgery, otherwise there is a risk for underestimation of NP infiltration. The present results might also be highly relevant for FRI and PJI.

Lung pathology of natural Babesia rossi infection in dogs

A proportion of Babesia rossi infections in dogs are classified as complicated and one of the most lethal complications is acute lung injury (ALI) and acute respiratory distress syndrome (ARDS). Most dogs that die succumb within 24 hours of presentation. The pulmonary pathology caused by B. rossi in dogs has not been described. The aim of this study was to provide a thorough macroscopic, histological and immunohistochemical description of the lung changes seen in dogs naturally infected with B. rossi that succumbed to the infection. Death was invariably accompanied by alveolar oedema. Histopathology showed acute interstitial pneumonia characterised by alveolar oedema and haemorrhages, with increased numbers of mononuclear leucocytes in alveolar walls and lumens. Intra-alveolar polymerised fibrin aggregates were observed in just over half the infected cases. Immunohistochemistry showed increased numbers of MAC387- and CD204-reactive monocyte-macrophages in alveolar walls and lumens, and increased CD3-reactive T-lymphocytes in alveolar walls, compared with controls. These histological features overlap to some extent (but far from perfectly) with the histological pattern of lung injury referred to as the exudative stage of diffuse alveolar damage (DAD) as is quite commonly reported in ALI/ARDS.

Antimicrobial peptides: Defending the mucosal epithelial barrier

The recent epidemic caused by aerosolized SARS-CoV-2 virus illustrates the importance and vulnerability of the mucosal epithelial barrier against infection. Antimicrobial proteins and peptides (AMPs) are key to the epithelial barrier, providing immunity against microbes. In primitive life forms, AMPs protect the integument and the gut against pathogenic microbes. AMPs have also evolved in humans and other mammals to enhance newer, complex innate and adaptive immunity to favor the persistence of commensals over pathogenic microbes. The canonical AMPs are helictical peptides that form lethal pores in microbial membranes. In higher life forms, this type of AMP is exemplified by the defensin family of AMPs. In epithelial tissues, defensins, and calprotectin (complex of S100A8 and S100A9) have evolved to work cooperatively. The mechanisms of action differ. Unlike defensins, calprotectin sequesters essential trace metals from microbes, which inhibits growth. This review focuses on defensins and calprotectin as AMPs that appear to work cooperatively to fortify the epithelial barrier against infection. The antimicrobial spectrum is broad with overlap between the two AMPs. In mice, experimental models highlight the contribution of both AMPs to candidiasis as a fungal infection and periodontitis resulting from bacterial dysbiosis. These AMPs appear to contribute to innate immunity in humans, protecting the commensal microflora and restricting the emergence of pathobionts and pathogens. A striking example in human innate immunity is that elevated serum calprotectin protects against neonatal sepsis. Calprotectin is also remarkable because of functional differences when localized in epithelial and neutrophil cytoplasm or released into the extracellular environment. In the cytoplasm, calprotectin appears to protect against invasive pathogens. Extracellularly, calprotectin can engage pathogen-recognition receptors to activate innate immune and proinflammatory mechanisms. In inflamed epithelial and other tissue spaces, calprotectin, DNA, and histones are released from degranulated neutrophils to form insoluble antimicrobial barriers termed neutrophil extracellular traps. Hence, calprotectin and other AMPs use several strategies to provide microbial control and stimulate innate immunity.

Sympathetic Nerves and Innate Immune System in the Spleen: Implications of Impairment in HIV-1 and Relevant Models

The immune and sympathetic nervous systems are major targets of human, murine and simian immunodeficiency viruses (HIV-1, MAIDS, and SIV, respectively). The spleen is a major reservoir for these retroviruses, providing a sanctuary for persistent infection of myeloid cells in the white and red pulps. This is despite the fact that circulating HIV-1 levels remain undetectable in infected patients receiving combined antiretroviral therapy. These viruses sequester in immune organs, preventing effective cures. The spleen remains understudied in its role in HIV-1 pathogenesis, despite it hosting a quarter of the body’s lymphocytes and diverse macrophage populations targeted by HIV-1. HIV-1 infection reduces the white pulp, and induces perivascular hyalinization, vascular dysfunction, tissue infarction, and chronic inflammation characterized by activated epithelial-like macrophages. LP-BM5, the retrovirus that induces MAIDS, is a well-established model of AIDS. Immune pathology in MAIDs is similar to SIV and HIV-1 infection. As in SIV and HIV, MAIDS markedly changes splenic architecture, and causes sympathetic dysfunction, contributing to inflammation and immune dysfunction. In MAIDs, SIV, and HIV, the viruses commandeer splenic macrophages for their replication, and shift macrophages to an M2 phenotype. Additionally, in plasmacytoid dendritic cells, HIV-1 blocks sympathetic augmentation of interferon-β (IFN-β) transcription, which promotes viral replication. Here, we review viral–sympathetic interactions in innate immunity and pathophysiology in the spleen in HIV-1 and relevant models. The situation remains that research in this area is still sparse and original hypotheses proposed largely remain unanswered.

M1 and M2 tumour-associated macrophages subsets in canine malignant mammary tumours: An immunohistochemical study

Among the innate and adaptative immune cells recruited to the tumour site, tumour associated macrophages (TAMs) are particularly abundant and by simplified classification can be classified into (M1) and (M2) TAMs. In the present study, we quantified by immunohistochemistry ionized calcium binding adaptor molecule 1 (Iba1)-positive total and CD204-positive M2-polarized TAMs in 60 canine malignant mammary tumours (CMMTs) to analyze the relationship between M1 or M2 response and the histopathologic features of examined CMMTs, the dogs' body condition score (BCS) and the progression of the neoplastic disease. The mean number of total and CD204+ TAMS were significantly higher in solid and in grade III than in grades I and II carcinomas. Moreover, the mean number of CD204-positive TAMs was significantly higher in CMMTs with lymphatic invasion and necrosis rather than CMMTs without. The presence of higher number of CD204-positive M2-polarized TAMs was associated with a worst outcome of the neoplastic disease: bitches bearing CMMTs with a prevalent M2-polarized TAM response had a median cancer-specific survival time of 449 days, while in animals with a M1-polarized TAM response the median cancer-specific survival time was 1209 days. The results of our study confirm that in CMMTs the presence of a M2-polarized TAMs response might affect the tumour development and behaviour. Finally, it strongly suggests the potential of CD204 expression as a prognostic factor.

CD204-Expressing Tumor-Associated Macrophages Are Associated With Malignant, High-Grade, and Hormone Receptor-Negative Canine Mammary Gland Tumors

Tumor-associated macrophages (TAMs) are an important component of leukocyte infiltration in tumors. TAMs can be classified into M1 and M2 phenotypes. In the present study, the expression of CD204, an M2-polarized macrophage receptor, was investigated by immunohistochemistry in the area surrounding TAMs in 101 cases of canine mammary gland tumor (CMT). We examined the relationship between M2-polarized TAMs and malignancy, histological subtype, histological grade, molecular subtype, hormone receptor (HR) status, and clinical obesity indices. The mean number of CD204-positive macrophages was significantly higher in malignant CMTs than in benign CMTs ( P = .000). The number of CD204-positive macrophages differed significantly between histological grades ( P = .000) and were significantly higher in grade III than in grades I and II. Moreover, the mean number of CD204-positive macrophages was significantly higher in HR-negative malignant CMTs than in HR-positive malignant CMTs ( P = .035) and in malignant CMTs with lymphatic invasion compared to malignant CMTs without lymphatic invasion ( P = .000). These findings suggest that CD204-positive macrophages might affect the development and behavior of CMTs and highlight the potential of CD204 as a prognostic factor.

Subtype-Specific Tumor-Associated Fibroblasts Contribute to the Pathogenesis of Uterine Leiomyoma

Recent genomic studies have identified subtypes of uterine leiomyoma (LM) with distinctive genetic alterations. Here, we report the elucidation of the biological characteristics of the two most prevalent uterine leiomyoma subtypes, MED12-mutant (MED12-LM) and HMGA2-overexpressing (HMGA2-LM) uterine leiomyomas. Because each tumor carries only one genetic alteration, both subtypes are considered to be monoclonal. Approximately 90% of cells in HMGA2-uterine leiomyoma were smooth muscle cells (SMC) with HMGA2 overexpression. In contrast, MED12-LM consisted of similar numbers of SMC and non-SMC, which were mostly tumor-associated fibroblasts (TAF). Paradoxically, TAF carried no mutations in MED12, suggesting an interaction between SMC and TAF to coordinate their growth. The higher amount of extracellular matrix in MED12-LM than HMGA2-LM was partially due to the high concentration of collagen-producing TAF. SMC growth in a xenograft assay was driven by progesterone in both uterine leiomyoma subtypes. In contrast, TAF in MED12-LM proliferated in response to estradiol, whereas progesterone had no effect. The high concentration of estrogen-responsive TAF in MED12-LM explains the inconsistent discoveries between in vivo and in vitro studies on the mitogenic effect of estrogen and raises questions regarding the accuracy of previous studies utilizing MED12-LM cell culture. In addition, the differential effects of estradiol and progesterone on these uterine leiomyoma subtypes emphasize the importance of subtypes and genotypes in designing nonsurgical therapeutic strategies for uterine leiomyoma. Cancer Res; 77(24); 6891-901. ©2017 AACR.

Splenic Damage during SIV Infection: Role of T-Cell Depletion and Macrophage Polarization and Infection

The effects of HIV infection on spleen and its cellular subsets have not been fully characterized, particularly for macrophages in which diverse populations exist. We used an accelerated SIV-infected macaque model to examine longitudinal effects on T-cell and macrophage populations and their susceptibilities to infection. Substantial lymphoid depletion occurred, characterized by follicular burn out and a loss of CD3 T lymphocytes, which was associated with cellular activation and transient dysregulations in CD4/CD8 ratios and memory effector populations. In contrast, the loss of CD68 and CD163(+)CD68(+) macrophages and increase in CD163 cells was irreversible, which began during acute infection and persisted until terminal disease. Mac387 macrophages and monocytes were transiently recruited into spleen, but were not sufficient to mitigate the changes in macrophage subsets. Type I interferon, M2 polarizing genes, and chemokine-chemokine receptor signaling were up-regulated in spleen and drove macrophage alterations. SIV-infected T cells were numerous within the white pulp during acute infection, but were rarely observed thereafter. CD68, CD163, and Mac387 macrophages were highly infected, which primarily occurred in the red pulp independent of T cells. Few macrophages underwent apoptosis, indicating that they are a long-lasting target for HIV/SIV. Our results identify macrophages as an important contributor to HIV/SIV infection in spleen and in promoting morphologic changes through the loss of specific macrophage subsets that mediate splenic organization.

Occurrence of immune cells in the intestinal wall of Squalius cephalus infected with Pomphorhynchus laevis

A sub-population of 34 specimens of chub, Squalius cephalus, was sampled from the River Brenta (Northern Italy) and examined for ecto- and endo-parasites. Pomphorhynchus laevis (Acanthocephala) was the only enteric helminth encountered. Immunofluorescence and ultrastructural studies were conducted on the intestines of chub. Near the site of parasite's attachment, mucous cells, mast cells (MCs), neutrophils and rodlet cells (RCs) were found to co-occur within the intestinal epithelium. The numbers of mucous cells, MCs and neutrophils were significantly higher in infected fish (Mann-Whitney U test, p < 0.05). Dual immunofluorescence staining with the lectin Dolichos Biflorus Agglutinin (DBA) and the macrophage-specific MAC387 monoclonal antibody, with parallel transmission electron microscopy, revealed that epithelial MCs often made intimate contact with the mucous cells. Degranulation of a large number of MCs around the site of the acanthocephalan's attachment and in proximity to mucous cells was also documented. MCs and neutrophils were abundant in the submucosa. Immune cells of the intestinal epithelium have been described at the ultrastructural level and their possible functions and interactions are discussed.

Immunohistochemical study and mRNA cytokine profile of the local immune response in cattle naturally infected with Calicophoron daubneyi

In order to recognize the local immune response of the definitive host to Calicophoron daubneyi natural infection, an immunohistochemical study was carried out in the reticulum and rumen in 49 naturally infected cattle. The role of cytokines (IL-4 and IL-10 interleukins and IFN-γ) in the activation of specific defence mechanisms was evaluated by reverse transcriptase quantitative polymerase chain reaction (RT-qPCR) assays to study cytokine mRNA expression. In all infected animals, CD3+ T lymphocytes seemed to be the main element of the inflammatory infiltrate in the reticular and ruminal lamina propria at the point of the parasite adhesion. Intraepithelial globule leukocytes also showed immunolabelling for CD3. Most CD3+ cells also expressed CD4 (T cell helper) antigen although sporadic CD8+-cytotoxic lymphocytes were observed. Local expression of IFN-γ was observed in damaged papillae at the site of parasite attachment and in scattered cells in the lamina propria. B cells (CD79αcy+, CD45+ and IgG+) were found constantly in relation to lymphoid aggregates. MAC387 was expressed in squamous epithelium and in macrophages of the lamina propria of affected papillae. Macrophages in this location also stained positively for CD163 and CD68. Intraepithelial Langerhans cells and macrophages located in the lamina propria showed immunopositivity for MHCII in the affected areas. RT-qPCR analysis confirmed a statistical significant increase of IFN-γ, and IL-10 expression (p<0.01) in the rumen associated with the presence of flukes. These findings suggest a predominant Th1 polarized local immune response with the probable involvement of Th regulatory cells in cattle C. daubneyi natural infection.

Morphological and physiological retinal degeneration induced by intravenous delivery of vitamin A dimers in rabbits

The eye uses vitamin A as a cofactor to sense light and, during this process, some vitamin A molecules dimerize, forming vitamin A dimers. A striking chemical signature of retinas undergoing degeneration in major eye diseases such as age-related macular degeneration (AMD) and Stargardt disease is the accumulation of these dimers in the retinal pigment epithelium (RPE) and Bruch's membrane (BM). However, it is not known whether dimers of vitamin A are secondary symptoms or primary insults that drive degeneration. Here, we present a chromatography-free method to prepare gram quantities of the vitamin A dimer, A2E, and show that intravenous administration of A2E to the rabbit results in retinal degeneration. A2E-damaged photoreceptors and RPE cells triggered inflammation, induced remolding of the choroidal vasculature and triggered a decline in the retina's response to light. Data suggest that vitamin A dimers are not bystanders, but can be primary drivers of retinal degeneration. Thus, preventing dimer formation could be a preemptive strategy to address serious forms of blindness.

Classically or alternatively activated bovine monocyte-derived macrophages in vitro do not resemble CD163/Calprotectin biased macrophage populations in the teat

The functional phenotype of resident macrophages significantly determines the character of an inflammatory response. In this study we identified two phenotypes of tissue macrophages in bovine teat tissue based on expression of Calprotectin and CD163. To investigate a possible link between the dichotomy in phenotype and functional properties of cells in association with different host mediators we set up an in vitro model with bovine monocyte-derived macrophages (MdM). In vitro differentiated MdM invariably and uniformly expressed both antigens. Classically activated MdM (IFN-γ priming and LPS stimulation) showed a decreased CD163 expression while alternative activation (IL-4/IL-13 priming) did not change expression of CD163 and Calprotectin. Differently activated MdM showed a clearly distinct expression of genes related to classical (IL-12, inducible NO synthase) or alternative activation (IL-10, arginase I). The presence of the inflammatory host mediator prostaglandin E(2) (PGE(2)) neither influenced expression of Calprotectin and CD163 nor gene expression profiles in MdM generated in the presence of PGE(2) (PGE(2)-MdM). Supernatants of PGE(2-)MdM, however, significantly dampened the migration of neutrophilic granulocytes. The results of this study highlight the discrepancy between in vivo and in vitro obtained macrophages and point to the necessity to analyze the functional capacities of bovine tissue macrophages in situ.

Prognostic value of tumour-associated macrophages in canine mammary tumours

Tumour-associated macrophages (TAMs) have already been associated in human breast cancer to a poor prognosis. As a part of a tumoural microenvironment, TAMs have an important contribution influencing neoplastic progression. Hitherto, in canine mammary tumours (CMT) the prognostic value of TAMs has not been reported. In this study, MAC387 immunohistochemical expression was evaluated in 59 CMTs (20 benign and 39 malignant). The TAM value was significantly higher in malignant than benign CMT (P = 0.011). In malignant CMT, TAMs were associated with skin ulceration (P = 0.022), histological type (P = 0.044), nuclear grade (P = 0.031) and tubular differentiation (P = 0.042). The survival analysis revealed a significant association between tumours with higher levels of TAMs and the decrease in overall survival (P = 0.030). TAMs have proven to have a prognostic value. These findings suggest the future possibility of using TAMs as a novel therapeutic target in CMT.

Monocyte maturation, HIV susceptibility, and transmigration across the blood brain barrier are critical in HIV neuropathogenesis

HIV continues to be a global health crisis with more than 34 million people infected worldwide (UNAIDS: Report on the Global AIDS Epidemic 2010, Geneva, World Health Organization). HIV enters the CNS within 2 weeks of infection and establishes a spectrum of HAND in a large percentage of infected individuals. These neurologic deficits greatly impact the quality of life of those infected with HIV. The establishment of HAND is largely attributed to monocyte transmigration, particularly that of a mature CD14(+)CD16(+) monocyte population, which is more susceptible to HIV infection, across the BBB into the CNS parenchyma in response to chemotactic signals. To enter the CNS, junctional proteins on the monocytes must participate in homo- and heterotypic interactions with those present on BMVECs of the BBB as they transmigrate across the barrier. This transmigration is responsible for bringing virus into the brain and establishing chronic neuroinflammation. While there is baseline trafficking of monocytes into the CNS, the increased chemotactic signals present during HIV infection of the brain promote exuberant monocyte transmigration into the CNS. This review will discuss the mechanisms of monocyte differentiation/maturation, HIV infectivity, and transmigration into the CNS parenchyma that contribute to the establishment of cognitive impairment in HIV-infected individuals. It will focus on markers of monocyte subpopulations, how differentiation/maturation alters HIV infectivity, and the mechanisms that promote their increased transmigration across the BBB into the CNS.

Cell-specific actions of HIV-Tat and morphine on opioid receptor expression in glia

HIV-1 patients who abuse opiate-based drugs, including heroin and morphine, are at a higher risk of developing HIV dementia. The effects of opiates are mediated predominantly through opioid receptors, which are expressed on glial cells. As HIV-1 infection in the CNS is restricted to glial cells, experiments were designed to measure the cell-specific effects of HIV Tat and morphine exposure on opioid receptor expression in both astrocytes and microglia. Specifically, the cell-type-specific pattern of mu opioid receptor (MOR), delta opioid receptor (DOR), and kappa opioid receptor (KOR) localization (surface vs. intracellular) and expression of opioid receptor mRNA were determined after exposure to morphine in the presence and the absence of Tat in primary cultured microglia and astrocytes. Data show that morphine treatment caused significantly decreased cell surface expression of opioid receptors in microglia but not in astrocytes. However, morphine treatment in the presence of Tat significantly increased intracellular expression of opioid receptors and prevented morphine-induced cell surface opioid receptor down-regulation in microglia. These findings document that cell surface opioid receptor expression is divergently regulated by morphine in microglia compared with in astrocytes, and further suggest that HIV-Tat could exacerbate opioid receptor signaling in microglia by increasing receptor expression and/or altering ligand-induced trafficking of opioid receptors.

Breast cancer expression of CD163, a macrophage scavenger receptor, is related to early distant recurrence and reduced patient survival

Cells of the monocyte/macrophage lineage are important for tumour cell migration, invasion and metastasis. Fusion between macrophages and cancer cells in animal models in vitro and in vivo causes hybrids with increased metastatic potential. Primary breast cancer cells were characterized for macrophage antigens to test if phenotypic resemblance to macrophages is related to early distant recurrence. Immunostaining for CD163, MAC387 and CD68 was performed in a breast cancer tissue micro array from 127 patients consequently followed up for a median of 13 years. Tumour-associated macrophages expressed all 3 antigens. The breast cancers expressed CD163 to 48%, MAC387 to 14% while CD68 was not expressed. TGF-beta staining intensity was positively related to both CD163 and MAC387 expression. Expression of CD163 in the cancer cells was compared to their DNA ploidy, Nottingham Histological Grade, TNM-stage, node state, presence of estrogen receptors and occurrence of distant metastases and survival. Cancers of a more advanced histological grade expressed CD163 to a higher extent. Cells expressing MAC387 were more common in cancers with a high proportion of CD163 positive cells. Multivariate analysis showed that expression of the macrophage antigen CD163 in breast cancer cells has a prognostic impact on the occurrence of distant metastases and reduced patient survival time.

BCG vaccination enhances resistance to M. tuberculosis infection in guinea pigs fed a low casein diet

In order to examine the relationship between malnutrition and tuberculosis development in vivo, a malnourished guinea pig model fed with a low casein (5%) diet was developed. After being fed with the low casein diet, the guinea pigs were infected with Mycobacterium (M.) tuberculosis Kurono strain by aerosol infection, and seven weeks later were subjected to histopathologic examination, colony-forming unit (CFU) assay, fluorescence-activated cell sorter (FACS) analysis and real-time reverse transcriptase-polymerase chain reaction (RT-PCR) for interferon (IFN)-gamma, tumor necrosis factor (TNF)-alpha, interleukin (IL)-12 and inducible nitric oxide synthase (iNOS) mRNA. Another group of guinea pigs were vaccinated subcutaneously with 10(6) CFU BCG Tokyo for three weeks and then similarly infected by aerosol. Eighty-eight% (7/8) of the malnourished guinea pigs succumbed to mycobacterial infection within 85 days after infection, while the malnourished guinea pigs vaccinated with BCG Tokyo survived. CFU assay showed that lung and splenic CFUs were higher in the low casein diet-fed groups than in the control diet (20% casein)-fed groups, although both groups had significantly lower CFUs after vaccination with BCG Tokyo (p<0.01). Examination of lung histopathology revealed that pulmonary granulomas were large and disorganized in the groups fed the low casein diet. The number of visible lesions on the surfaces of the fixed lungs in guinea pigs fed control diet+BCG and low casein diet+BCG was low significantly. Pan T-, CD4-, CD8- and Mac antigen-positive cells were also recognized in the infected lung tissues of low casein-fed guinea pigs and Pan T-, CD4- and Mac antigen-positive cells increased after vaccination with BCG Tokyo. Expression of IFN-gamma, TNF-alpha, IL-12 and iNOS mRNA was also recognized in the infected lung tissues of low casein-fed guinea pigs and IFN-gamma and TNF-alpha mRNA expression was enhanced with BCG vaccination. These results indicate that malnutrition exacerbates mycobacterial infection and that malnourished infected hosts may be protected by BCG vaccination.

Tumor resection cavity administered iodine-131-labeled antitenascin 81C6 radioimmunotherapy in patients with malignant glioma: neuropathology aspects

INTRODUCTION

The neurohistological findings in patients treated with targeted beta emitters such as (131)I are poorly described. We report a histopathologic analysis from patients treated with combined external beam therapy and a brachytherapy consisting of a (131)I-labeled monoclonal antibody (mAb) injected into surgically created resection cavities during brain tumor resections.

METHODS

Directed tissue samples of the cavity walls were obtained because of suspected tumor recurrence from 28 patients. Samples and clinical follow-up were evaluated on all patients (Group A) based on total radiation dose received and a subset of these (n=18; Group B, proximal therapy subset) who had received external beam therapy within <or=3 months of mAb therapy and undergoing 26 biopsies over 37 months. Histologic outcomes were "proliferative glioma," "quiescent glioma" and negative for neoplasm. Statistical analysis was used to assess the casual relation between total absorbed dose ((131)I-mAb+external beam) and histologic diagnosis.

RESULTS

The lesions observed after (131)I-mAb therapy were qualitatively similar to those reported for other types of radiation therapy; however, the high localized dose rate and absorbed doses produced by the short range of (131)I beta particles seem to have resulted in an earlier necrotic reaction in the tumor bed. Among all 28 (Group A) patients, median survival from tissue analysis after mAb therapy depended on histopathology and total radiation absorbed dose. Median survival for patients with tissue classified as proliferative glioma, quiescent glioma and negative for neoplasm were 3.5, 15 and 27.5 months, respectively. Without categorization, total dose was a significant predictor of survival (P<.002) where patients with higher doses had better prognoses. For example, median survival in patients receiving a total radiation dose greater than 86 Gy was 19 months compared with 7 months for those receiving less than 86 Gy.

CONCLUSIONS

Histopathologic analysis correlated with prognosis. Among all patients (Group A) there was a significant correlation between biopsy outcome, survival, and total radiation absorbed dose. Among the Group B proximal therapy patients, the neuropathologic changes were qualitatively similar to those described for external beam therapy and interstitial brachytherapy.

Significance of CD25 positive cells and macrophages in noncrescentic IgA nephropathy

The aim of this study was to determine whether infiltration by CD25 positive cells, macrophages, and activated macrophages in the kidney is predictive of chronic histological injury and renal prognosis in adults with noncrescentic IgA nephropathy. Renal biopsies of 36 patients with noncrescentic IgA nephropathy were examined by immunohistochemistry for glomerular and interstitial CD4, CD8, and CD25 positive cells, monocytes/macrophage (Mac387), and activated macrophages (27E10). Renal injury (glomerulosclerosis, mesangial cell hypercellularity, tubular atrophy, and interstitial fibrosis) at the time of biopsy and renal prognosis (follow-up creatinine and creatinine clearance) were assessed. The mean follow-up period was 22.5 +/- 16.5 months. The number of interstitial CD8 positive cells was the best predictor of renal injury at the time of biopsy, and was positively correlated with glomerulosclerosis (p = 0.04), tubular atrophy (p = 0.04), and interstitial fibrosis (p = 0.01) but not with mesangial cell hypercellularity. The number of interstitial Mac387 and 27E10 positive cells were the best predictors of renal prognosis (r2 = 0.33 and 0.34 respectively, both p < 0.01). These data suggest the presence of CD8 cells and macrophages in the kidney at the time of biopsy could potentially serve as pathological markers to identify patients with IgA nephropathy, which may warrant more aggressive medical therapy.

Mucosal defence along the gastrointestinal tract of cats and dogs

Diseases that are associated with infections or allergic reactions in the gastrointestinal and respiratory tracts are major causes of morbidity in both cats and dogs. Future strategies for the control of these conditions require a greater understanding of the cellular and molecular mechanisms involved in the induction and regulation of responses at the mucosal surfaces. Historically, the majority of the fundamental studies have been carried out in rodents or with tissues obtained from man, but the expanding range of reagents available for the study of farm and companion animals provides opportunities for study in a wider range of animals including cats and dogs. To date, these studies have tended to be focussed on characterising the cellular distributions in healthy animals and in groups of cats and dogs identified as having an increased risk of mucosal disturbance. Where species comparisons of mucosal immune systems have been made, the results have tended to be divided between monogastric and ruminant animals. It is then not surprising that the mucosal immune systems of both cats and dogs bear greatest similarity to that documented for man and pigs. For example, IgA is the dominant immunoglobulin in mucosal secretions of cats and dogs and oral tolerance can be induced following the introduction of novel antigens into the diet. Also like several other species, cats become transiently hypersensitive to the newly introduced dietary antigen prior to the establishment of tolerance. In contrast, there are a number of potentially important differences. In particular, there are significant differences between cats and dogs in the expression MHC class II molecules on gut epithelial cells. Similarly, it has been reported that cats have elevated numbers of intraepithelial lymphocytes (IEL) and that a proportion of these express surface IgM. It remains to be determined if these differences reflect the way in which the animals are maintained and if they may have greater biological significance.

Distribution of leucocyte subsets in bronchial mucosa from dogs with eosinophilic bronchopneumopathy

Immunohistochemistry was used to characterize the distribution of leucocyte subsets in the bronchial mucosa of 11 dogs with idiopathic eosinophilic bronchopneumopathy (EBP). Formalin-fixed tissues from all dogs were included in the study, but frozen tissue from only one dog was available. MHC class II(+) cells were found in moderate numbers in the lamina propria (LP). These cells were morphologically either dendritic-like cells or macrophages, but many macrophages did not express MHC class II. Such molecules were expressed by occasional fibroblasts. L1(+) cells, which formed a relatively small component of the LP inflammatory infiltrate, were morphologically either macrophages or polymorphonuclear cells (probably eosinophils). IgA(+) plasma cells were found in varying numbers in the LP, mostly in association with glandular tissue. IgG(+) plasma cells were less common, and IgM(+) plasma cells were present in low numbers. Many CD3(+) cells were present in the LP. In the single case from which frozen tissue was available, most of the lymphocytes were labelled with CD4 marker, while smaller numbers were CD8(+) T cells. Most of the lymphocytes in this case were positively labelled with T-cell receptor (TCR)-alphabeta marker. TCR-gammadelta(+) cells, although less common, were present in significant numbers throughout the LP. CDlc(+) dendritic cells were numerous in the epithelium and in the LP, immediately beneath the basement membrane. These findings, which were similar to those described in human asthma, are suggestive of a Th2 dominant immune response in canine EBP. As in human asthma, this provides a possible basis for new forms of treatment in canine EBP.

Distribution of leucocyte subsets in the canine respiratory tract

Histochemistry and immunohistochemistry were used to characterize leucocyte subsets in the respiratory tract of 15 outbred dogs (five aged <6 months and 10 aged >1 year) that had no evidence of respiratory disease. No organized nose- or bronchus-associated lymphoid tissue was observed in any of the sections examined. IgA(+) plasma cells predominated in nasal mucosa and in all parts of the bronchial tree, with fewer IgG(+) and IgM(+) plasma cells. The numbers of IgA(+) and IgM(+) cells were significantly greater in the nasal mucosa than in any other part of the respiratory mucosa. There were significantly fewer IgA(+), IgG(+) and IgM(+) cells in all parts of the respiratory tract in the puppies than in the adults. The number and distribution of mast cells and cells expressing MHC class II, L1 or CD1c were recorded. Mast cells were mainly found in the subepithelial lamina propria of nasal and bronchial mucosa and in the alveolar interstitium, and cells expressing IgE had a similar distribution. Mast cells were also present within muscle layers of the bronchial tree. The numbers of mast cells and MHC class II(+) cells were significantly greater in the nasal mucosa than in any other part of the respiratory mucosa. In the nose, carina and primary and secondary bronchus, there were significantly more mast cells and MHC class II(+) cells in puppies than in adult dogs, whereas the numbers of L1(+) cells and CD1c(+) cells in most sites were significantly greater in older dogs. There were significantly more CD3(+) and CD8(+) cells in the nasal mucosa than in any part of the bronchial mucosa. In most parts of the respiratory mucosa, CD4(+), CD8(+) and TCR alphabeta(+) cells were present in significantly greater numbers in adults than in puppies. All parts of the respiratory tract had similar numbers of mucosal CD4(+) and CD8(+) T lymphocytes. TCR gammadelta(+) cells were absent or sparse in all samples. These data, obtained from dogs without respiratory disease, will enable comparisons to be made with dogs suffering from infectious or inflammatory nasal, bronchial and pulmonary diseases.

An immunohistochemical study of canine nasal aspergillosis

In this study, histochemistry and immunohistochemistry were used to characterize the phenotype and distribution of leucocytes in the distal nasal mucosa of 15 dogs with nasal aspergillosis. The most consistent histopathological finding was a severe, predominantly lymphoplasmacytic, inflammatory infiltration of the lamina propria. Fungal hyphae were not observed to invade the mucosa but were found at the mucosal surface and within material collected from the nasal cavity. The main immunohistochemical findings were (1) a predominance of IgG(+) plasma cells over IgA(+) and IgM(+) plasma cells, (2) significant numbers of macrophages and dendritic cells expressing MHC class II molecules, (3) macrophages and neutrophils expressing L1 antigen and (4) a mixture of CD4(+) and CD8(+) T cells. These findings are consistent with a dominant Th1-regulated cell-mediated immune response. The nature of the inflammatory infiltrate and the lack of invasiveness of the mucosa by the fungus, together with the clinical course of the disease and the apparent immunocompetence of the affected dogs, suggest that canine nasal aspergillosis resembles the chronic erosive non-invasive fungal sinusitis described in human patients.

Patterns of cerebral inflammatory response in a rabbit model of intrauterine infection-mediated brain lesion

Although the fetal inflammatory response syndrome seems crucial to the association between intrauterine infection and white matter disease in human preterm infants, the underlying mechanisms remain unclear. Using our previously described rabbit model of cerebral cell death in the white matter and hippocampus induced by intrauterine Escherichia coli infection, we investigated inflammatory and astroglial responses in placenta and brain tissues, in correlation with cell death distribution. Brains and placentas were studied 12, 24, or 48 h following intrauterine inoculation of E. coli or saline (groups G12, G24, and G48). Diffuse monocyte-macrophage infiltrates positive for inducible nitric oxide synthase (i-NOS) were significantly more marked in G24 and G48 placentas than in controls. In the G48 fetuses with both diffuse cell death and focal periventricular white matter cysts mimicking cystic periventricular leukomalacia, a strong rabbit macrophage and inducible nitric oxide synthase immunostaining was observed at the border of these cystic lesions. In contrast, in the fetuses with only diffuse and significant cell death, no inflammatory or astroglial responses were detected in the white matter or hippocampus. Cell death was accompanied by i-NOS immunostaining in the hippocampus but not the white matter. Hippocampal cells positive for i-NOS usually displayed a neuronal phenotype. In this model, focal white matter cysts are accompanied by a robust inflammatory response, and diffuse cell death, which may mimic the white matter and hippocampal damage seen in very and extremely pre-term infants, occur in the absence of a detectable brain inflammatory response.

Proinflammatory cytokines upregulate expression of calprotectin (L1 protein, MRP-8/MRP-14) in cultured human keratinocytes

BACKGROUND

Normal skin contains no epidermal calprotectin. In biopsies from various inflammatory skin disorders, however, this antimicrobial protein occurs in the cytoplasm of keratinocytes.

OBJECTIVES

To exclude the possibility of epidermal uptake of calprotectin from granulocytes and macrophages in diseased skin, we investigated whether cytokine-stimulated human keratinocytes can express calprotectin in vitro.

METHODS

Keratinocytes from healthy individuals were cultured in serum-free keratinocyte medium. The cells were stimulated with different cytokines [interferon (IFN)-gamma, tumour necrosis factor (TNF)-alpha, interleukin (IL)-1beta, IL-10 and IL-13], both separately and in various combinations. Cytoplasmic protein levels of calprotectin were measured by an enzyme-linked immunosorbent assay performed on fixed adherent keratinocytes, and mRNA expression was determined by semiquantitative reverse transcription-polymerase chain reaction (RT-PCR).

RESULTS

Calprotectin was produced by cytokine-stimulated keratinocytes, especially in response to combinations of the proinflammatory cytokines, which showed an additive upregulatory effect. When expression of mRNA for the light (MRP-8) and heavy (MRP-14) calprotectin chain was determined by RT-PCR, their respective levels were shown to be increased four- to ninefold and three- to fivefold after 24 h of combined stimulation with IFN-gamma and TNF-alpha. The time course of calprotectin production showed no significant elevation for the first 16 h but then increased and peaked after 36 h.

CONCLUSIONS

Cultured human keratinocytes stimulated with proinflammatory cytokines produce calprotectin, suggesting that epidermal expression of this antimicrobial protein in diseased skin reflects compartmentalized synthesis rather than uptake from dermal inflammatory cells.

Characterization of immune cell populations in oral mucosal tissue of healthy adult cats

The aim of this study was to characterize the leucocyte subsets present in the oral mucosa of healthy cats. Immunohistochemical labelling and computer-assisted morphometric analysis was used to identify expression of MHC class II, CD3, CD79a, IgG, IgM, IgA, and leucocyte antigen L1 (L1) by cells in sections from 19 cats, and expression of CD4 and CD8 by cells in sections from 17 cats. Mast cells were detected by toluidine blue staining. In the epithelial compartment, CD3(+) intraepithelial lymphocytes were detected, and CD8(+) cells were more common than CD4(+) cells. MHC class II labelling revealed intraepithelial and subepithelial cells with a characteristic dendritic morphology. In some sections these dendritic cells were closely associated with subepithelial clusters of CD3(+) T cells containing both CD4(+) and CD8(+) cells. In the lamina propria and submucosal compartments, the cells most commonly identified were mast cells. CD3(+) T-lymphocytes were also observed, and CD4(+) and CD8(+) cells were detected in similar numbers. L1(+) and CD79(+) cells were detected least frequently. The few plasma cells present were generally found to be either IgG(+) or IgA(+). Within the stroma surrounding the salivary glands, CD79a(+) and IgA(+) cells predominated. Slight epithelial labelling for L1 was seen in some sections. The normal feline oral mucosa clearly contains a range of immune cell populations.

Wound healing response in the presence of stromal irregularities after excimer laser treatment

PURPOSE

To trace the fate of stromal irregularities after excimer laser treatment and to increase our knowledge of the reasons why surface irregularities in the ablation bed cause inferior postoperative results.

METHODS

Twelve New Zealand White rabbits received a transepithelial photoablation to a preset depth of 60 microm. An electron microscopy specimen grid was then placed on the denuded stroma and another 20 microm ablation was applied in order to produce surface irregularities. Another six rabbits received a plano transepithelial photoablation to a preset depth of 80 microm. The treated corneas were harvested at various timepoints and differentially further processed for microradiography, hematoxylin-eosin -, hyaluronan (HA)- and leukocyte protein L1 staining.

RESULTS

In the grid treated corneas the subepithelial mesh pattern is clearly discernible after 1 week, and after 4 weeks it is replaced by a subepithelial layer containing HA and water. The thinning of this layer between 1 and 12 weeks is statistically significant (p<0.05). After 4 and 8 week the plano treated corneas only exhibit some subepithelial HA- and water accumulation. After 1 day the grid treated corneas show an extensive stromal infiltration of leukocytes. In the plano treated corneas the leukocytes mainly remain on the surface.

CONCLUSIONS

During the healing process stromal irregularities are flattened, leaving a homogeneous zone with increased water content. This subepithelial layer is rarefying as new subepithelial tissue is forming. Postablational irregularities induce a more pronounced healing reaction when compared to a smooth ablation surface. Leukocyte infiltration seems to play a role in this process.

Detection of European porcine reproductive and respiratory syndrome virus in porcine alveolar macrophages by two-colour immunofluorescence and in-situ hybridization-immunohistochemistry double labelling

Two groups of five pigs aged 6 weeks were each infected oronasally with one of two different European isolates of porcine reproductive and respiratory syndrome virus (PRRSV). The animals were killed sequentially at 4, 7, 14 or 21 days post-inoculation for examination. The methods used consisted of histopathology, and mono- and double-labelling techniques based on in-situ hybridization, immunofluorescence and immunohistochemistry. Porcine alveolar macrophages (PAMs) contained large amounts of PRRSV antigen and PRRSV RNA, as shown by double labelling with (1) either PRRSV immunofluorescence or PRRSV-specific in-situ hybridization with digoxigenin-labelled riboprobes, and (2) immunolabelling with Mac 387 antibody for calprotectin. Expression of PRRSV-RNA was not detectable in cytokeratin-positive hypertrophic and proliferating pneumocytes or in cells of alveolar ducts or bronchiolar epithelium. The use of two-colour immunofluorescence with confocal laser scanning microscopy and double labelling with in-situ hybridization-immunohistochemistry showed that PAMs were the only pulmonary target cells. This contradicts earlier reports that epithelial pulmonary cells may also be infected by PRRSV.

Comparison of the microanatomical distributions of macrophages and dendritic cells in normal and diseased tonsils

The palatine tonsils play an important role in immunologic surveillance and resistance to infection in the upper aerodigestive tract. Dendritic cells and macrophages function to capture and process antigen and present it to T lymphocytes, a critical step in the early immune response. Few studies have characterized the distribution and phenotype of those antigen-presenting cells in the normal palatine tonsil, or determined how those parameters change with disease. Immunohistochemical analysis was performed to determine the microanatomical distribution, quantity, morphology, and phenotype of macrophages and dendritic cells in both normal and diseased tonsils. Differences were observed in macrophage and dendritic cell distribution, quantity, and phenotype in the surface and crypt epithelium. The number of macrophages was significantly increased in all compartments in all disease groups (p < .05), although the number of macrophages that expressed phenotypes of maturity and/or activation was not concomitantly increased. In the surface epithelium, Langerhans and interdigitating cells decreased significantly with disease (p < .05). Chronic infection may impose an immunosuppressive effect on responses within tonsil tissue, affecting the immunologic factors responsible for macrophage maturation and activation.

Increases in intrahepatic CD68 positive cells, MAC387 positive cells, and proinflammatory cytokines (particularly interleukin 18) in chronic hepatitis C infection

BACKGROUND

Upregulation of Th1 associated intrahepatic cytokines in chronic hepatitis C virus (HCV) infection should lead to a significant non-specific cellular immune response, a prerequisite for viral clearance. However, to date, the role of this non-specific response in HCV has been understudied.

AIMS

To analyse the intrahepatic macrophage activity in chronic HCV infection by immunostaining and by quantitation of cytokine mRNA.

METHODS

HCV positive liver tissues (chronic hepatitis, n=10; cirrhosis, n=5) were immunostained for CD68, MAC387, and semiquantitated by polymerase chain reaction for intrahepatic cytokine mRNAs (interferon gamma (IFNgamma), interleukin 1beta (IL-1beta), IL-6, IL-18, tumour necrosis factor alpha (TNFalpha), and macrophage inflammatory protein 1beta (MIP1beta)). HCV negative normal liver tissues (for cytokines, n=6; for immunostaining, n=5) were included as controls.

RESULTS

MAC387(+) cells were focally increased in areas of erosion at the limiting plate while lobular staining was minimal. CD68(+) staining was diffuse in both portal (increased in HCV) and lobular areas. The portal tract (mean) density of CD68(+) and MAC387(+) cells was significantly increased in patients with HCV compared with normal tissue. IFNgamma and IL-18 mRNA levels were highly correlated and significantly upregulated in chronic hepatitis and cirrhotic tissue versus controls. TNFalpha mRNA was upregulated in chronic hepatitis without cirrhosis, while IL-6 mRNA was significantly downregulated. IL-1beta, IL-6, and MIP1beta mRNA levels were significantly correlated with portal tract MAC387(+) cell density.

CONCLUSIONS

The significant upregulation of IFNgamma and IL-18 mRNA and significant correlations between IFNgamma and other proinflammatory cytokines, suggest a Th1/cell mediated intrahepatic immune response in chronic HCV infection. However, further clarification of the cellular sources of these cytokines is required.

An immunohistochemical study of histiocytic ulcerative colitis in boxer dogs

Histiocytic ulcerative colitis (HUC) is an inflammatory bowel disease (IBD) that occurs predominantly in dogs of the boxer breed. The lesions are characterized by mucosal ulceration and mixed inflammatory cell infiltrate that includes the presence of periodic acid-Schiff (PAS)-positive macrophages. However, the phenotype of the inflammatory cells has not been characterized further. In the present study, immunohistochemistry and computer-aided morphometric analysis were used to define populations of leucocyte subsets in the colon of 14 boxer dogs with HUC. Biopsies from six of these dogs included both lesional and non-lesional regions. Colonic tissue from 11 dogs of various breeds without evidence of gastrointestinal disease served as controls. In HUC lesions there were significantly more IgG(+), IgG3(+), IgG4(+)plasma cells, CD3(+)T cells, MHC class II(+)cells, L1(+)cells and PAS(+)cells in the lamina propria than in both control colon and non-lesional colonic regions of affected dogs. In the epithelial compartment, goblet cells were significantly decreased in HUC lesions compared to both control and non-lesional HUC colon, and intensity of enterocyte MHC class II expression was significantly increased. These observations are similar to those documented in human IBD, especially ulcerative colitis, and suggest an important role for the mucosal immune system in the pathogenesis of canine HUC.

Characterization of a B cell surface antigen with homology to the S100 protein MRP8

The S100 proteins comprise a large sub-family of the EF-hand calcium-binding proteins. Here we describe a novel monoclonal antibody recognizing a B cell surface antigen. This monoclonal antibody immunoprecipitates three proteins in the 12-18 kDa range and the smallest of these proteins has a striking homology at its amino-terminus to human MRP8, a myeloid specific member of the S100 family. Similarly to MRP8 in myeloid cells, this antigen is expressed in the cytoplasm of B cells and is secreted by LPS-induced activated B cells. This surface antigen is not B cell specific. Since MRP8 is not expressed by lymphoid cells, however, this antibody appears to recognize a new member of the S100 family.

Epidermal calprotectin in drug-induced toxic epidermal necrolysis

Calcium ions (Ca++) in excess alter cell viability. Their potential role in drug-induced toxic epidermal necrolysis (TEN) was investigated. Thirteen TEN patients were biopsied at the site of early bullous lesions and on clinically normal-looking skin at least 2 cm distant from blisters. Immunohistochemistry was applied using the mouse monoclonal antibody Mac 387 recognizing the cytosolic protein complex L1 (calprotectin). The L1 antigen is a calcium-binding protein expressed by human granulocytes, monocytes-macrophages and injured epidermis, but not by normal epidermis and other cells harboured in the skin. The majority (8/13) of TEN samples from apparently non-involved skin expressed the L1 antigen in a patch-like pattern inside the epidermis where inflammatory cells were scant or absent. As assessed by computerized image analysis of TEN bullous skin, the intensity of the L1 expression in the epidermis was not statistically correlated with the amount of the infiltrating inflammatory cells (Mac 387+ macrophages, UCLH1 + T lymphocytes and Factor XIIIa+ dendrocytes) present in the dermis and in the epidermis. Such findings suggest a key role for keratinocytes in the production of the L1 calcium-binding complex. As the L1 complex formation is a calcium-dependent process, one of the first biological events in TEN could be a dramatic increase in keratinocytes intracellular Ca++ concentration following damage by the involved drug metabolites. The ultimate toxic cell dysregulation would result from the disturbance in the intracellular Ca++ homeostasis.

Analysis of leucocyte subsets in the canine intestine

Immunohistochemistry and computer-aided morphometric analysis were used to define populations of leucocyte subsets in the intestinal tract of an outbred population of dogs with no evidence of gastrointestinal disease. In the small intestinal lamina propria, B cells and plasma cells (IgA+, IgM+ and IgG+) were prominent in peri-crypt regions, with a significant trend for a reduction in the number of cells towards the villous tip (P < 0.0001). By contrast, lamina propria T cells (CD3+) and T-cell subsets (CD4+ and CD8+) were present in greatest numbers at the tip of the villus, with significantly decreasing numbers towards the crypt regions (P < 0.0001). In the lamina propria, CD4+ cells outnumbered CD8+ cells (P = 0.05), but the opposite was true of the epithelial compartment (P < 0.001). The distribution of CD5+ lymphocytes was similar to that of CD3+ cells, in both the lamina propria and epithelial compartments. The numbers and distribution of cells expressing MHC class II, L1 and CD45 were recorded. Numerous eosinophils were present in the lamina propria, and an intra-epithelial population was also noted, especially in the crypt epithelium. Mast cells, which were mainly found in the subepithelial lamina propria, were also present within muscle layers, and cells expressing IgE had a similar distribution. Similar populations of cells were recorded in the colonic lamina propria and epithelium. The quantitative and qualitative data from this study will enable comparisons to be made with dogs suffering from inflammatory bowel diseases.

Characterization of immunocompetent cells in the diseased canine periodontium

The beagle dog with naturally occurring periodontal disease is one of the most widely used animal models in periodontal research for histological studies on disease pathogenesis and on the effect of potential therapeutic regimens. However, previous studies were restricted to morphological assessment of immunocompetent cells because of the lack of available cell-specific markers. In this study we systematically characterized the specificity and immunoreactivity of a panel of anti-human antibodies for identification (ABC method) of immunocompetent cells in formalin-fixed, EDTA-decalcified, paraffin-embedded inflamed periodontal tissues obtained from six beagle dogs. Canine lymph nodes and a panel of different human tissues served as positive controls. Polyclonal anti-CD3 immunolabeled canine T-lymphocytes specifically. Anti-CD79alpha (clone HM57) reacted with B-lymphocytes and plasma cells, and CD79alpha (clone JCP117) showed no staining in canine tissues. Neutrophils, monocytes, small macrophages, and keratinocytes reacted with an anti-myeloid/histiocyte antibody (clone MAC387). Anti-CD68 (clones PG-M1 and EBM11) immunolabeled large macrophages and plasma cells. Clone EBM11 also stained osteoclasts and cementoclasts. With the exception of JCB117, all antibodies revealed similarly favorable immunolabeling of canine and human immunocompetent cells. Long-term EDTA decalcification appeared to weaken immunostaining of plasma cells with HM57. MAC387 and CD68 can be used to distinguish macrophages in different differentiation stages in canine periodontal tissues. (J Histochem Cytochem 46:1443-1454, 1998)

Histiocytic sarcoma of the spleen associated with hypoalbuminemia, hypo gamma-globulinemia and thrombocytopenia as a possibly unique clinical entity--report of three cases

We report three patients with histiocytic sarcoma of the spleen associated with severe hypoalbuminemia, hypo gamma-globulinemia and thrombocytopenia. After the clinical diagnosis of splenic tumor of unknown origin was made, all three patients underwent splenectomy. The histiocytic origin of the tumor was confirmed histopathologically and immunohistochemically using a panel of antibodies. In contrast to malignant histiocytosis (MH), which typically reveals severe generalized clinical manifestations and a rapidly fatal course caused by the disseminated proliferation of neoplastic histiocytes, these patients were asymptomatic or showed only mild clinical symptoms for a long period of time until the recurrence was detected by which time the tumor cells had already spread to other organs. All three cases were characteristically associated with hypoalbuminemia, hypo gamma-globulinemia and thrombocytopenia, which returned to normal after splenectomy. Splenic histiocytic sarcoma with the features described here may represent a unique clinical entity, distinct from MH.

Chemotaxins C5a and fMLP induce release of calprotectin (leucocyte L1 protein) from polymorphonuclear cells in vitro

AIMS

To determine whether the chemotaxins C5a and formyl peptide (fMLP) can stimulate the release of calprotectin, the major leucocyte protein of polymorphonuclear neutrophils (PMN).

METHODS

A dose response curve for the uptake of 125I labelled rC5a and fMLP in PMN was determined by radioimmunoassay. The unlabelled chemotaxins were then incubated with PMN and the concentration of calprotectin in PMN lysates and supernatants was measured by an enzyme immunoassay.

RESULTS

Both rC5a and fMLP induced release of calprotectin from PMN in a dose dependent manner as determined by a reduction in intracellular calprotectin concentration. A minimum of approximately 10% of total PMN calprotectin was retained at concentrations of 10-100 nM of rC5a and 0.1-10.0 nM of fMLP. Antibodies to C5a reduced the rC5a mediated release of calprotectin, and the fMLP antagonist N-t-Boc-MLP inhibited the fMLP induced calprotectin release. Because receptors for rC5a (CD88) and fMLP are G protein coupled and thought to be pertussis toxin sensitive, PMN were incubated with this toxin before the experiments. The toxin was found to reduce uptake of rC5a by the cells and to inhibit rC5a and fMLP mediated calprotectin release.

CONCLUSIONS

rC5a and fMLP mediate release of calprotectin from PMN in vitro. This effect might be important during human infections in vivo.

Intestinal immune cells in Strongyloides stercoralis infection

BACKGROUND

Strongyloides stercoralis can cause a wide spectrum of disease in man, ranging from a chronic asymptomatic infection to a hyperinfective, often fatal syndrome. In rodents, spontaneous expulsion of Strongyloides spp occurs after experimental infection. Mast cells, goblet cells, and eosinophils have been identified as possible effectors of this expulsion.

AIMS

To investigate intestinal histopathology and mucosal immunity in immunocompetent patients with chronic S stercoralis infection.

METHODS

Jejunal biopsies were performed in 19 immunocompetent patients with a positive stool examination for S stercoralis and few or no symptoms, and in seven healthy controls. Specimens were processed for histopathological analysis and stained by the immunoperoxidase technique, using the following monoclonal antibodies: CD2, CD3, CD4, CD8, anti-T cell receptor (TcR) gamma/delta, RFD1 and RFD7 (two different macrophage markers), Ki67+ (proliferating) cells, antihuman leucocyte antigen (HLA)-DR, and anticollagen IV. In addition, CD25+ cells, mast cells, IgE expressing cells, calprotectin containing cells, and neutrophil elastase positive cells were stained by the alkaline phosphatase method.

RESULTS

Jejunal morphology and the numbers of different T cell subsets, mast cells, IgE expressing cells, eosinophils, and goblet cells were unaffected by S stercoralis infection. Conversely, the numbers of mature macrophages and dividing enterocytes in the crypts were reduced significantly. Crypt enterocytes did not express HLA-DR in both groups. The expression of HLA-DR by villus enterocytes was also comparable in patients and controls. There were no activated (CD25+) cells in the mucosa of either patients or controls.

CONCLUSIONS

Compared with seven healthy uninfected volunteers, a group of 19 Brazilians with clinically mild strongyloides infection showed no abnormality of mucosal structure and no increase in non-specific inflammatory cells. Likewise, there was no increase in mucosal T cells or macrophages.

The accessory cell populations in ulcerative colitis: a comparison between the colon and appendix in colitis and acute appendicitis

We present an immunohistochemical study of accessory cells in acute appendicitis and ulcerative colitis (UC). By comparing these two diseases, it is possible to distinguish between changes associated with inflammatory bowel disease and those resulting from nonspecific intestinal inflammation. Nine total colectomy specimens from patients with UC, in which the appendix was also involved, were compared with nine cases of acute appendicitis. Accessory cells were stained for CD68 (PGMI), ACPI (acid cysteine proteinase inhibitor), S100 protein, MAC387 (calgranulin), CD1a, factor XIIIa, and WR18 (HLA class II). In ulcerative colitis, but not acute appendicitis, there was extension of a network of S100 positive dendritic cells into the crptal mucosa, and these S100-positive dendritic cells were closely aligned with the epithelium. The epithelium in UC, but not in acute appendicitis, showed intense upregulation of HLA class II, and this was particularly marked at the crypt bases. Dendritic, MAC387-positive cells were seen only in UC. In both diseases there were abundant ACPI-positive accessory cells in the cryptal areas, a population normally restricted to the dome areas. Factor XIIIa- and PGM1-positive cells, although abundant in both conditions, had distributions similar to those that we had previously shown in normal controls. No CD1a-positive cells were identified in either UC or acute appendicitis. We hypothesize that S100 identifies a subpopulation of activated macrophages. The concentration of this subpopulation, in close contact with the epithelium, which also shows altered expression of HLA class II antigens, suggests that a component of the immune response is targeting this area in UC. In addition, we also suggest that the identification of MAC387-positive dendritic cells in UC reflects increased macrophage turnover in inflammatory bowel disease.

Immunohistochemical characterization of the cellular infiltrates in Sjögren's syndrome, rheumatoid arthritis and osteoarthritis with special reference to calprotectin-producing cells

The aim of this study was to analyse the nature of infiltrating cells in minor salivary glands of patients with Sjögren's syndrome (SS). Furthermore, we wanted to characterize the tissue distribution of calprotectin-producing cells in inflamed salivary gland tissue of SS and in synovial tissue of patients with rheumatoid arthritis (RA) and osteoarthritis (OA). Cryostat sections of labial salivary gland tissue from patients with SS and synovial tissue from RA and OA patients were stained (ABC-immunoperoxidase technique) using monoclonal antibodies (MoAbs) to T cells (CD3), monocytes/macrophages (CD14, CD68), and calprotectin. Monocytes and macrophages were widely distributed in focal infiltrates of salivary gland tissue from SS patients. Calprotectin markers showed a distinct staining of infiltrating macrophages and around blood vessel walls. In synovial tissue samples, calprotectin was expressed in a high percentage of cells in the synovial lining, the subsynovium, and vessel walls. The percentages of cells stained for calprotectin were significantly higher in RA than in OA and SS tissues. Antibodies to the calprotectin complex stained cells with a similar distribution as antibodies against the separate polypeptide chains of calprotectin. The localization and differentiated expression of calprotectin in these chronic inflammatory conditions indicate a role in the inflammatory process and may be an additional marker of macrophages/granulocytes in SS, RA and OA.

Disseminated aspergillosis in a dog: an immunohistochemical study

An immunohistopathological study of a case of disseminated aspergillosis in a 4-year-old female German shepherd dog was carried out to characterize the cellular infiltrate within the granulomatous lesions of various organs. Polyclonal antibodies specific for canine immunoglobulins IgG, IgM, IgA, complement C3c, human CD3 antigen (pan T-lymphocyte marker), human lysozyme and alpha-1-antitrypsin and a monoclonal antibody for myeloid/ histocyte antigen (MAC 387) (macrophage marker) were used. In the mycotic granulomata of the heart, liver, spleen and kidneys a correlation was found between the numbers of CD3+ T lymphocytes and lysozyme+ macrophages (r = 0.9944, P = 0.0056), and between the numbers of CD3+ T lymphocytes and MAC 387+ macrophages (r = 0.9943, P = 0.0057).

Characterization of verruciform xanthoma by in situ hybridization and immunohistochemistry

Verruciform xanthoma (VX) is a rare, benign lesion, mainly found in the oral mucosa. Histologically and ultrastructurally, the lesion is characteristic and well defined. However, the etiology of the lesion remains unclear. The purpose of the present study was to elaborate upon the pathogenesis of VX by evaluation of an additional series of oral examples for human papillomaviruses (HPV), using immunohistochemistry and in situ hybridization, and to further characterize the cellular components of VX immunohistochemically. Twelve specimens diagnosed as VX were retrospectively collected. One of the twelve specimens was positive for HPV types 6/11 by in situ hybridization. None of the twelve specimens demonstrated the presence of HPV antigen by immunohistochemistry. By immunohistochemical studies, the predominant cells in the inflammatory infiltrate were T cells. The foam cells were of monocyte/macrophage lineage. S-100-positive (Langerhans) cells were occasionally found in the suprabasal layer of the epithelium. HLA-DR-positive keratinocytes were noted at the intense inflammatory sites. Taken together, these findings suggest that an immune response may play a role, at least in part, in VX pathogenesis.

The monoclonal antibody Mac 387 recognizes three S100 proteins in human neutrophils

Mac 387, a murine mAb, was previously described to detect a complex form of MRP-14 and MRP-8, two calcium-binding proteins of the S100 family, but recent experiments suggested that Mac 387 recognized only MRP-14. Using two-dimensional polyacrylamide gel electrophoresis and the very sensitive enhanced chemiluminescence detection system, the immunoreactivity of Mac 387 was compared with that of a polyclonal antibody raised against purified MRP-8, but cross-reacting with MRP-14 and p6, a novel S100 protein. Under such conditions, Mac 387 was found to recognize the three S100 proteins. This result suggests that Mac 387 might recognize an epitope common of the proteins of the S100 family.