The chemokines CCL11, CCL20, CCL21, and CCL24 are preferentially expressed in polarized human secondary lymphoid follicles

Chemokines regulate cellular trafficking to and from lymphoid follicles. Here, the distribution pattern of four CCL chemokines is defined by in situ hybridization in human lymphoid follicles from tonsils and lymph nodes (LNs) of newborns and adults. Cells expressing CCL11 (eotaxin) and CCL20 (Exodus) were preferentially located within follicles, while cells expressing CCL21 (secondary lymphoid-tissue chemokine) and CCL24 (eotaxin-2) mRNA were almost exclusively found in the perifollicular areas. Hence, the two CCR3-binding chemokines, CCL11 and CCL24, showed a mutually exclusive expression pattern in the intra- and extra-follicular areas, respectively. Chemokine gene expression paralleled follicular maturation: in tonsils, where approximately 80% of follicles are polarized, CCL11 and CCL20 mRNA-positive cells were detected more frequently than in lymph nodes from adults, where about half of follicles are non-polarized. No intrafollicular chemokine expression was detectable in the primary follicles from newborns. Extrafollicular cells expressing CCL21 and CCL24 were again more frequent in tonsils than in LNs from adults. The observed preferential presence of cells expressing CC chemokines in polarized human lymphoid follicles indicates that chemokines are not only instrumental in the induction of follicle formation, but may also be involved in their further differentiation.     

Survival in rectal cancer is predicted by T cell infiltration of tumour-associated lymphoid nodules

Lymphoid nodules are a normal component of the mucosa of the rectum, but little is known about their function and whether they contribute to the host immune response in malignancy. In rectal cancer specimens from patients with local (n = 18), regional (n = 12) and distant (n = 10) disease, we quantified T cell (CD3, CD25) and dendritic cell (CD1a, CD83) levels at the tumour margin as well as within tumour‐associated lymphoid nodules. In normal tissue CD3⁺, but not CD25⁺, T cells are concentrated at high levels within lymphoid nodules, with significantly fewer cells found in surrounding normal mucosa (P = 0·001). Mature (CD83), but not immature (CD1a), dendritic cells in normal tissue are also found clustered almost exclusively within lymphoid nodules (P = < 0·0001). In rectal tumours, both CD3⁺ T cells (P = 0·004) and CD83⁺ dendritic cells (P = 0·0001) are also localized preferentially within tumour‐associated lymphoid nodules. However, when comparing tumour specimens to normal rectal tissue, the average density of CD3⁺ T cells (P = 0·0005) and CD83⁺ dendritic cells (P = 0·0006) in tumour‐associated lymphoid nodules was significantly less than that seen in lymphoid nodules in normal mucosa. Interestingly, regardless of where quantified, T cell and dendritic cell levels did not depend upon the stage of disease. Increased CD3⁺ T cell infiltration of tumour‐associated lymphoid nodules predicted improved survival, independent of stage (P = 0·05). Other T cell (CD25) markers and different levels of CD1a⁺ or CD83⁺ dendritic cells did not predict survival. Tumour‐associated lymphoid nodules, enriched in dendritic cells and T cells, may be an important site for antigen presentation and increased T cell infiltration may be a marker for improved survival.     

Cryptopatches and isolated lymphoid follicles: dynamic lymphoid tissues dispensable for the generation of intraepithelial lymphocytes

In comparison to secondary lymphoid organs, gut-associated lymphoid tissues such as isolated lymphoid follicles (ILF) and cryptopatches (CP) have been less intensively studied. To gain a better insight into processes regulating organization and function of these structures, which are believed to participate in immune responses and extrathymic T cell development, we characterized the lymphoid structures of the murine small intestine in more detail. The size and cellular composition of small intestinal lymphoid aggregations were analyzed in C57BL/6 and BALB/c wild-type and lymphotoxin (LT)-deficient mice, by flow cytometry, histology and automated multi-color immunofluorescence microscopy evaluating large coherent areas of the intestine. These evaluations demonstrate that aggregated lymphoid structures in the small intestine vary in size and cellular composition, with a majority of structures not matching the current definitions of CP or ILF. Accordingly, significant variations depending on species, age and mouse strain were observed. Furthermore, small bowel transplantation revealed a rapid exchange of B but not T cells between host and grafted tissue. Moreover, LT-deficient animals lack any intestinal lymphoid aggregations yet possess the complete panel of intraepithelial lymphocytes (IEL). In summary, our observations disclose intestinal lymphoid aggregations as dynamic structures with a great deal of inborn plasticity and demonstrate their dispensability for the generation of IEL.     

The formation and function of tertiary lymphoid follicles in chronic pulmonary inflammation

Tertiary lymphoid follicles (TLFs) can develop in the respiratory tract in response to infections or chronic inflammation. However, their functional relevance remains unclear because they are implicated in both protective and pathological responses. In contrast to homeostatic conditions, external antigens and damage to the lung tissue may drive TLF formation in inflamed lungs, and once established, the presence of pulmonary TLFs may signal the progression of chronic lung disease. This novel concept will be discussed in light of recent work in chronic obstructive pulmonary disease and how changes in the pulmonary microbiota may drive and direct TLF formation and function. We will also discuss the cellularity of TLFs at the pulmonary mucosa, with emphasis on the potential roles of lymphoid tissue inducer cells, and B‐ and T‐cell aggregates, and will examine the function of key chemokines and cytokines including CXCL13 and interleukin‐17, in the formation and maintenance of pulmonary TLFs.     

Morphology of the epithelium of the lower rectum and the anal canal in the adult human

The anal canal is an important body part clinically. However, there is no agreement about the epithelium of the anal canal, the anal transitional zone (ATZ) epithelium in particular. The aim of this study is to clarify the structure of the epithelium of the human lower rectum and anal canal. Intact rectum and anus obtained from patients who underwent surgery for rectal carcinoma were examined by light and scanning electron microscopy (LM and SEM). By LM, three types of epithelium were observed in the anal canal: simple columnar epithelium, stratified squamous epithelium, and stratified columnar epithelium. The lower rectum was composed of simple columnar epithelium. SEM findings showed stratified squamous epithelium that consisted of squamous cells with microridges, changing to simple columnar epithelium consisting of columnar cells with short microvilli at the anorectal line. LM and SEM observations in a one-to-one ratio revealed that the area of stratified columnar epithelium based on LM corresponded to the anal crypt and sinus. In conclusion, the epithelium of the human anal canal was fundamentally composed of simple columnar epithelium and stratified squamous epithelium. We found no evidence of the ATZ.     

Iocalization of Epstein-Barr virus genome in lymphoid cells in poorly differentiated adenocarcinoma with lymphoid strorna of the colon

Poorly differentiated adenocarcinoma with lymphoid stroma occurred in the transverse colon of a 77 year old female. Numerous small lymphocytes and plasma cells were distributed in the tumor stroma. Non-isotopic in situ hybridization study for Epstein-Barr (EBV)-related small nuclear RNA (EBER-1) revealed positive signals in the nuclei of a few lymphocytes in the tumor stroma, while the tumor cell nuclei were not labeled. lrnmunostaining for latent membrane protein-1 was negative. The significance of detection of the EBV-infected lymphocytes in the colon tumor strorna is discussed.     

Ontogeny, distribution and structure of aggregated lymphoid follicles in the large intestine of sheep

Aggregates of lymphocytes were demonstrated from 70 days gestation (term 150 days in sheep) in the proximal colon and rectum. Immunoperoxidase staining for 5′-bromo-2′-deoxyuridine incorporation and IgM, indicated that the lymphocyte population of lymphoid follicles in fetal sheep colon was actively dividing and surface IgM positive. Enzyme histochemistry for 5′-nucleotidase showed that the lymphocytes developed in a meshwork of positive reticular cells, suggestive of developing follicles. Follicle aggregates were distributed in a characteristic pattern in lambs, with major accumulations in the ascending colon and in the rectum. In adult sheep a partial atrophy of follicle aggregates was observed. The microscopic structure of large intestinal aggregates showed similarities to the jejunal Peyer's patch (PP), with broad follicles containing a prominent corona and wide interfollicular areas in older lambs. The apparent deep penetration of crypts into the lymphoid tissue proper, which is a frequently reported phenomenon for colon follicles, was dependent on the contractile state of the mucosa, as judged from its absence in specimens where the intestinal wall had been stretched before fixation.     

Reflex responses of neurons in the inferior mesenteric ganglion to mechanical stimulation of the colon, rectum, anal canal, and urinary bladder in the dog

Unitary discharges were recorded from the inferior mesenteric ganglion of decerebrate dogs. Eighty-one units were identified as sympathetic postganglionic neurons innervating the colon and rectum by collision test performed by stimulation of the lumbar colonic nerve. Discharges of four units were enhanced simultaneously with an increased outflow of the renal nerve by pinching a toe. Thus, those units were regarded as vasoconstrictors of colonic blood vessels. Sixty-five units whose discharges were depressed or not affected by the pinching were regarded as neurons innervating colonic smooth muscle or mucosa (colonic units). Discharges were enhanced in the majority of the colonic units by colonic, rectal, and vesical distension, and mechanical stimulation of the anal canal, while discharges were depressed in a few units by rectal and vesical distension, and the anal canal stimulation. The number and percentage of the depressed units increased not only after cutting the hypogastric nerves and descending branches of the lumbar colonic nerve but also after transection of the caudal pons. The reflex depressions disappeared after transection at the bulbospinal junction, but the reflex enhancements remained. These results indicate that the colonic units are enhanced through a spinal reflex by the inflows from the distal colon, rectum, anal canal, and urinary bladder through the lumbar colonic, hypogastric, pelvic, and pudendal nerves, while a few are inhibited through a supraspinal reflex by inflows through the pelvic and pudendal nerves.     

Distribution of ‘dome’ type lymphoid follicles and morphology of microfold cells (M cells) in the human Bauhin''s valve, cecum and proximal ascending colon

The distribution of ‘dome’ type lymphoid follicles and the morphology of their M cells were studied in human Bauhin's valves, cecums and proximal ascending colons obtained during surgery performed on 11 patients. The lymphoid follicles existed as solitary follicles, and their number was remarkably large in the Bauhin's valve than in the cecum and proximal ascending colon. Scanning electron microscopy (SEM) disclosed lymphoid follicles forming domes that were surrounded by villi or crypts and M cells with microfolds in the dome epithelium. Transmission electron microscopy (TEM) disclosed microfolds, enfolded lymphocytes and the other typical characteristics of M cells in the Bauhin's valve, cecum and proximal ascending colon. These morphological findings were compatible with previously reported findings regarding the M cells in human Peyer's patches. This study was presented in part at the 24th Annual Meeting of the Clinical Electron Microscopy Society of Japan, on Septermber 19, 1992.     

Anatomy of the sigmoid colon, rectum, and the rectovaginal pouch in women with enterocele and anterior rectal wall procidentia

This study describes the anatomy of the rectovaginal pouch, the sigmoid colon, and rectum in women with posterior enterocele and anterior rectal wall procidentia. The anatomy of rectovaginal pouch, sigmoid colon, and rectum was described in 36 women with an enterocele (group A) and compared with those of 43 women (group B) without pelvic organ prolapse. Women with previous incontinence or prolapse surgery were excluded. The mean age in group A was 58 years (40-75) and in group B 35 years (19-64; P < 0.001). There were 15 nulliparas in group B. Nine women in group A had an internal anterior rectal wall procidentia, and one woman had an external anterior rectal wall procidentia. In group A, the rectovaginal pouch was significantly deeper, the sigmoid mesocolon at S1 shorter and showed more often a straight course (P < 0.05). These characteristics (termed "grande fosse pelvienne") were present in 23 women (64%) in group A and in 6 (14%) in group B, three of the latter were young nulliparas (P < 0.001). Age, parity, menopausal status, body mass index, constipation, and varicose veins were not associated with a grande fosse pelvienne. The typical anatomy in women with an enterocele and anterior rectal wall procidentia was a sigmoid colon with a straight course and a short mesentery at S1 and a rectovaginal pouch that covered more than half of the vaginal length. It may be a congenital condition and important in the development of an enterocele and rectal wall procidentia.     

Spindle cell proliferations of the sigmoid colon,rectum and anus: a review with emphasis on perineurioma

A wide range of spindle cell proliferations are found uncommonly in the sigmoid colon, rectum and anus. They usually present as polyps, and include reactive lesions and benign and malignant neoplasms which may be primary or metastatic. They are less frequently described in the literature compared to those in the upper gastrointestinal tract, and may be underdiagnosed. The widespread use of sigmoidoscopy in symptomatic patients and bowel cancer screening programmes means that histopathologists must be aware of, and adopt a logical approach to, diagnosing spindle cell proliferations in biopsy and polypectomy specimens. This is particularly relevant given the strong association of some mesenchymal polyps with hereditary cancer syndromes. This review article will focus on perineurioma and the recent debate in relation to its overlap with fibroblastic polyp. The clinical, endoscopic, histological and immunohistochemical features of spindle cell proliferations which should be considered in the differential diagnosis of perineurioma will be discussed. There is also a brief reference to malignant spindle cell tumours of diagnostic importance.     

Involvement of the sacral parasympathetic nucleus in the innervation of the descending colon and rectum in cats

Studies in anesthetized (urethane, 1.5 g/kg, i.p.) cats using retrograde transport of horseradish peroxidase addressed the locations and morphometric characteristics of neurons in the sacral parasympathetic nucleus of the spinal cord innervating the descending colon and rectum. Marker solution was injected beneath the serous membrane of the study areas of the large intestine. Transcardiac perfusion with fixative solution was performed 48 h later and frontal sections of the sacral segments of the spinal cord were prepared; these were processed by the Mesulam method (1978). The results showed that these areas of the large intestine receive innervation from neurons in the sacral parasympathetic nucleus located in spinal cord segments SI, SII, and SIII. The largest number of labeled cells was seen in segment SII. The neurons of this nucleus innervating the study areas of the large intestine formed two longitudinally distributed group (a lateral and a dorsal), the cells of which differed in terms of size and the orientation of the long axis. The largest number of labeled cells was seen in the lateral group. __________ Translated from Morfologiya, Vol. 133, No. 1, pp. 38–41, January–February, 2008.     

Salmonid T cells assemble in the thymus, spleen and in novel interbranchial lymphoid tissue

In modern bony fishes, or teleost fish, the general lack of leucocyte markers has greatly hampered investigations of the anatomy of the immune system and its reactions involved in inflammatory responses. We have previously reported the cloning and sequencing of the salmon CD3 complex, molecules that are specifically expressed in T cells. Here, we generate and validate sera recognizing a peptide sequence of the CD3ε chain. Flow cytometry analysis revealed high numbers of CD3ε(+) or T cells in the thymus, gill and intestine, whereas lower numbers were detected in the head kidney, spleen and peripheral blood leucocytes. Subsequent morphological analysis showed accumulations of T cells in the thymus and spleen and in the newly discovered gill-located interbranchial lymphoid tissue. In the latter, the T cells are embedded in a meshwork of epithelial cells and in the spleen, they cluster in the white pulp surrounding ellipsoids. The anatomical organization of the salmonid thymic cortex and medulla seems to be composed of three layers consisting of a sub-epithelial medulla-like zone, an intermediate cortex-like zone and finally another cortex-like basal zone. Our study in the salmonid thymus reports a previously non-described tissue organization. In the intestinal tract, abundant T cells were found embedded in the epithelium. In non-lymphoid organs, the presence of T cells was limited. The results show that the interbranchial lymphoid tissue is quantitatively a very important site of T cell aggregation, strategically located to facilitate antigen encounter. The interbranchial lymphoid tissue has no resemblance to previously described lymphoid tissues.     

Prognostic significance of nucleolar organizing regions (NORs) in carcinomas of the sigmoid colon and rectum.

The prognostic significance of silver-binding nucleolar organizing regions (AgNORs) has been evaluated in tissue sections of biopsies taken from 70 primary adenocarcinomas of the colon sigmoid (n = 25) and rectum (n = 45) prior to their curative resection. A significant correlation between five-year survival rate and the mean AgNOR number per tumour cell (p less than 0.001) and the mean size of silver stained dots (p less than 0.05) was found according to the univariate Kaplan-Meier survival analysis. There was no significant relationship between AgNOR content and grade of malignancy, pT categories or pN categories. Multivariate survival analysis of covariates (Cox regression model) revealed a set of five variables that significantly influenced the patients' outcome: pN categories, AgNOR content, pT categories, maximum grade of malignancy and number of inflammatory cells. From the clinical and pathological parameters studied, pN and pT categories as well as the mean AgNOR number were the most important variables predicting death from colorectal carcinoma. Since the analysis of AgNORs can be performed on routinely processed paraffin-embedded tissue, this method may be of potential use in pretherapeutic assessment of the biologic aggressiveness of the disease.     

Focal hyperplastic hepatocellular nodules in hepatic venous outflow obstruction: a clinicopathological study of four patients and 24 nodules

AIMS: In hepatic venous outflow obstruction (Budd-Chiari syndrome), focal hepatocellular nodules are occasionally discovered showing variable morphology. These could be interpreted either as neoplastic (adenoma), regenerative (large regenerative nodule) or reactive to abnormal vasculature (focal nodular hyperplasia). The aim of this study was to investigate their histogenesis and to determine their morphological characteristics in order to provide diagnostic criteria. MATERIAL AND METHODS: Twenty-four hepatocellular nodules were studied, which were found in three explanted livers and in one additional autopsied liver from four patients with Budd-Chiari syndrome. As controls, we employed three explanted livers without nodules from patients who also suffered from Budd-Chiari syndrome. We attempted to classify the nodules morphologically as either adenoma-like, large regenerative nodule or focal nodular hyperplasia-like, using criteria from the literature. RESULTS: Out of the four cases, we observed two nodules in each of two livers, five in the third one and up to 15 in the remaining one. The size of the nodules ranged from 4 to 25 mm. Eleven nodules could be categorized as large regenerative nodules (two of them with a central scar), seven as focal nodular hyperplasia-like and six as adenoma-like. Some large regenerative nodules showed proliferated arteries with muscular hyperplasia similar to that seen in focal nodular hyperplasia. In the individual livers we could find nodules of various categories. Patchy or diffuse monoacinar regeneration was seen in most cases (six out of seven cases) in the macroscopically non-nodular liver parenchyma. In addition, thrombotic obstruction of portal vein branches was present in all except one of the nodular cases, but in none of the controls. Thus, it appears that portal venous obstructions are frequently, but not invariably associated with the development of nodules. CONCLUSIONS: The hepatocellular nodules seen in livers from patients with Budd-Chiari syndrome share morphological characteristics with large regenerative nodules, focal nodular hyperplasia and hepatocellular adenomas. Their multiplicity, the existence of mixed lesions, the frequent hepatocellular regenerative background as well as the frequently associated portal venous obstructions suggest that these nodules are regenerative in nature and conditioned by an uneven blood perfusion throughout the liver. In their differential diagnosis, the clinicopathological context in which they occur is of paramount importance and should allow recognition that those resembling adenomas may not be true neoplasms.     

Nerves in the intersphincteric space of the human anal canal with special reference to their continuation to the enteric nerve plexus of the rectum

In the intersphincteric space of the anal canal, nerves are thought to “change” from autonomic to somatic at the level of the squamous‐columnar epithelial junction of the anal canal. To compare the nerve configuration in the intersphincteric space with the configuration in adjacent areas of the human rectum, we immunohistochemically assessed tissue samples from 12 donated cadavers, using antibodies to S100, neuronal nitric oxide synthase (nNOS), and tyrosine hydroxylase (TH). Antibody to S100 revealed a clear difference in intramuscular nerve distribution patterns between the circular and longitudinal muscle layers of the most inferior part of the rectum, with the former having a plexus‐like configuration, while the latter contained short, longitudinally running nerves. Most of the intramural ganglion cells in the anal canal were restricted to above the epithelial junction, but some were located just below that level. Near or at the level of the epithelial junction, the nerves along the rectal adventitia and Auerbach's nerve plexus joined to form intersphincteric nerves, with all these nerves containing both nNOS‐positive parasympathetic and TH‐positive sympathetic nerve fibers. Thus, it was histologically difficult to distinguish somatic intersphincteric nerves from the autonomic Auerbach's plexus. In the intersphincteric space, the autonomic nerve elements with intrapelvic courses seemed to “borrow” a nerve pathway in the peripheral branches of the pudendal nerve. Injury to the intersphincteric nerve during surgery may result in loss of innervation in the major part of the internal anal sphincter. Clin. Anat. 26:843–854, 2013. © 2013 Wiley Periodicals, Inc.     

Comparison of four assays for human papillomavirus detection in the anal canal

ObjectiveAnal cancer is preceded by high-risk human papillomavirus (HRHPV) infection, predominantly HPV16. No HPV assay is licenced for use in anal screening. We aimed to determine the sensitivity and specificity of four anal canal swab HPV assays to predict high-grade squamous epithelial lesions (HSIL).MethodsIn a cohort of Australian HIV-positive and negative gay and bisexual men, we compared the sensitivity and specificity of detection of 13 anal HRHPV genotypes by Linear Array (LA), Cobas 4800, EuroArray, and Anyplex II HPV28 (+ and ++ cut offs), compared their ability to predict prevalent anal HSIL, and compared anal canal HRHPV detection with HRHPV isolated from HSIL using laser capture microdissection (LCM).ResultsA total of 475 participants had baseline results available for all four assays (166, 35.0% HIV positive), and 169 participants had a diagnosis of cytological and/or histological HSIL. The HPV16 and any HRHPV detection were highest with Anyplex II HPV28 (+) (156, 32.8% 95% CI 28.6–37.2 and 359, 75.6%, 95% CI 71.5–79.4, respectively). For detection of concurrent HSIL and HPV16, the assay sensitivity was similar, ranging from 49.1%, 95% CI 41.4–56.9 (Anyplex II HPV28 ++) to 55.0%, 95% CI 47.2–62.7 (Anyplex II HPV28 +). For concurrent HSIL and any HRHPV detection, EuroArray was more specific than Anyplex II HPV28 (+) (45.9% 95% CI 40.2–51.7 vs 36.7%, 95% CI 31.3–42.4, p = 0.021) and had comparable specificity with Anyplex II HPV28 (++) (45.9% vs 47.2%, 95% CI 41.5–53.0, p = 0.75). All assays had high sensitivities for predicting HPV16 detected on LCM (92.5–97.5%). Anyplex II HPV28 and EuroArray were significantly more sensitive than LA for lesions caused by non-HPV16 HRHPV types on LCM.DiscussionAnyplex II HPV28 and EuroArray detected more non-16 HRHPV genotypes than LA. Increasing the Anyplex II HPV28 cutoff improved specificity without compromising sensitivity for detection of concurrent HSIL.