Microscopic colitis: prevalence and distribution throughout the colon in patients with chronic diarrhoea

BACKGROUND: Microscopic colitis presents with chronic diarrhoea with or without abdominal pain. Microscopic colitis is an important cause of chronic diarrhoea. It can be distributed throughout the colon, as well as limited to the right colon. Microscopic colitis is associated with coeliac disease. We studied the prevalence and distribution of microscopic colitis in patients with diarrhoea and normal colonoscopy and we studied the association with coeliac disease. METHODS: Colonoscopy was performed. Biopsies were taken from every segment of the colon. Lymphocytic colitis was defined as the presence of more than 20 lymphocytes per 100 epithelial cells and collagenous colitis was defined as thickening of the basal membrane of more than 10 microm. Upper endoscopy was performed if upper intestinal symptoms were present. If this was the case, small bowel biopsies were taken. RESULTS: Microscopic colitis was found in 13 out of 103 patients. The distribution was diffuse throughout the colon in ten and restricted to the right colon in three patients. In seven patients, upper endoscopy was performed. Marsh I/II lesions were found in six out of seven patients. CONCLUSION: Microscopic colitis was limited to the right colon in 23% of patients. Biopsies of macroscopically normal colonic mucosa in patients with diarrhoea is mandatory.     

Plasmacellular hyperplasia after allogeneic bone marrow transplantation

B lymphoid cells with monotypic immunoglobulin (Ig) expression, i.e., a single Ig heavy chain isotype combined with a single light chain type, were observed in five of nine patients after allogeneic bone marrow transplantation. Three patients exhibited plasmacellular hyperplasia of lymph nodes and spleen; in one case the monotypic cells were immunoblasts in a lymph node, and one patient suffered from an immunoblastic lymphoma along the gastrointestinal tract. We present the clinical history and the detailed (immuno) histologic analysis of lymphoid tissue from three patients. In DNA analysis of lymph node using DNA probes specific for the JH-gene segment of Ig heavy chains and for light chains, bands indicative of single Ig gene rearrangements were not observed. Thus, the monotypic B lymphoid elements represent polyclonal B cell expansion.     

Disease induction by human microbial pathogens in plant-model systems: potential, problems and prospects

Relatively simple eukaryotic model organisms such as the genetic model weed plant Arabidopsis thaliana possess an innate immune system that shares important similarities with its mammalian counterpart. In fact, some human pathogens infect Arabidopsis and cause overt disease with human symptomology. In such cases, decisive elements of the plant's immune system are likely to be targeted by the same microbial factors that are necessary for causing disease in humans. These similarities can be exploited to identify elementary microbial pathogenicity factors and their corresponding targets in a green host. This circumvents important cost aspects that often frustrate studies in humans or animal models and, in addition, results in facile ethical clearance.     

Tumor cell growth fraction in Hodgkin's disease.

The growth fraction of tumor cells was studied in 45 cases of Hodgkin's disease by means of a recently developed double immunostaining technique using monoclonal antibody Ki-1, which reacts selectively with Hodgkin and Reed-Sternberg cells in tissues affected by Hodgkin's disease, and antibody Ki-67, which recognizes a cell proliferation-associated nuclear antigen. The medians of the growth fractions of the tumor cells in all histologic subtypes of Hodgkin's disease varied between 78% and 83%. In none of the cases investigated did we find a growth fraction below 50%. Furthermore, mononucleated Hodgkin cells as well as multi-nucleated Reed-Sternberg cells showed a similar Ki-67 labeling index, indicating that both tumor cell types belong to the proliferating pool of this malignancy.     

Langerhans cell histiocytosis first presenting in the skin in adults: frequent association with a second haematological malignancy

Background Langerhans cell histiocytosis (LCH) in adults first presenting in the skin is rare. Guidelines for staging, treatment and follow‐up are lacking. Objectives To better define staging procedures, treatment results and clinical course in adult patients with LCH first presenting in the skin. Methods Eighteen adult patients with LCH first presenting in the skin were collected from five centres collaborating in the Dutch Cutaneous Lymphoma Group. Clinical records and (skin) biopsy specimens were reviewed and follow‐up data were obtained. A literature search on adult patients with LCH presenting in the skin was performed. Results Staging procedures showed extracutaneous disease in three of 16 patients who were adequately staged. One patient had a histologically confirmed lytic LCH bone lesion, while two patients had a myelodysplastic syndrome. During follow‐up two of 18 patients developed extracutaneous localizations of LCH. Five patients developed a second haematological malignancy, including (myelo)monocytic leukaemia (two cases), histiocytic sarcoma (one case), diffuse large B‐cell lymphoma (one case) and peripheral T‐cell lymphoma (one case). Review of the literature revealed six other adult patients with a second haematological malignancy preceding or following a diagnosis of LCH. Conclusions The results of the present study suggest an increased risk of a second haematological malignancy in adult patients with LCH presenting in the skin. Extensive staging at presentation and long‐term follow‐up are therefore warranted in such patients.     

Acute thymus involution in infancy and childhood: a reliable marker for duration of acute illness

To evaluate the relationship between histologic parameters and clinical data, we studied thymus histology in 234 fetuses and young children who died after a short period of acute illness. Thymus weight and volume percentages of interstitium, cortex, and medulla were significantly related to prenatal or postnatal status and age of the patient. Thymus weight was related to the duration of acute illness only in prenatal patients. The histology, categorized in five grades according to appearance of macrophages (with a starry-sky aspect) in the cortex, increase of interlobular interstitium, and lymphodepletion of the cortex, correlated significantly with the duration of acute illness and not with any other clinical parameter. This finding enables the pathologist to estimate the duration of acute disease before death.     

Evidcnce for the Functional Heterogeneity of the Two Sites of Transferrin in Vitro

A recently developed crossed immunoelectrophoretic method for displaying and quantitating the four possible molecular species of transferrin has been utilized to assess the relative effectiveness of each site of rabbit and human diferric transferrin in providing iron to rabbit reticulocytes. The site which appears to reside in the N-terminal half of the rabbit protein was found to be at least 5 times more effective than its counterpart. However, both sites may serve as iron donors in monoferric as well as diferric rabbit transferrins. It is also possible that iron may be removed from rabbit transferrin in pairwise as well as sequential fashion. In human diferric transferrin, the site in the C-terminal domain functions as the better iron donor for rabbit reticulocytes.     

Paediatric nodal marginal zone B‐cell lymphadenopathy of the neck: a Haemophilus influenzae‐driven immune disorder?

Many hyperplasias and lymphomas of marginal zone B‐cells are associated with infection. We identified six children and one adolescent with cervical lymphadenopathy showing prominent polyclonal nodal marginal zone hyperplasia (pNMZH) and four adolescents with monoclonal paediatric nodal marginal zone lymphoma (pNMZL). The clonality status was assessed using BIOMED‐2‐IG PCR analysis. Haemophilus influenzae was identified in all six cases of pNMZH that could be tested by direct culture (N = 3) or a very sensitive PCR for the H. influenzae gyrase gene in frozen materials (N = 5). H. influenzae was not detected in three pNMZLs and 28 non‐specific reactive cervical lymph nodes of age‐matched controls, except for a single control node that was obtained during oropharyngeal surgery for a cleft palate showing very low copy numbers of H. influenzae. pNMZH patients were younger than pNMZL patients (median age 12 versus 21 years). pNMZH showed a prominent nodular appearance with variable fibrosis without acute inflammation. Within the nodules, the expanded germinal centres and variably sized marginal zones were colonized by activated B‐cells with weak expression of IgD and lack of CD10 and/or BCL6 expression. Some areas showed skewed light chain expression in plasma cells (4/5 cases lambda). In four cases tested, this was confirmed by flow cytometry for surface Ig (3/4 cases lambda). In contrast, pNMZL showed more extensive expansion of marginal zones by centrocytoid cells and often expression of BCL2 protein. Several H. influenzae strains are known to interact with the constant part of IgD on human B‐cells, leading to their polyclonal proliferation and activation. We speculate that in vivo stimulation of IgD+ marginal zone B‐cells by this bacterium may be implicated in this particular lymphadenopathy that should be distinguished from monoclonal pNMZL. Copyright © 2015 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.