Yoshimasa Yonamine

Mac1 discriminates unusual CD4−CD8− double-negative T cells bearing αβ antigen receptor from conventional ones with either CD4 or CD8 in murine lung

Abstract Pulmonary intraparenchymal leukocytes were purified from normal mice. By flow cytometry, 20–30% of the lymphocytes were positive for the expression of Mac1, a cell-surface antigen largely restricted to macrophages, neutrophils and natural killer (NK) cells. Sorted Mac1 + lung lymphocytes were large and had abundant cytoplasm with few azurophilic granules. Because Mac1 + lymphocytes did not contain any asiallo GM1 + cells, they are not likely to be NK cells. By a two-color flow cytometric analysis, Mac1 + lymphocytes were demonstrated to be TCR- αβ intermediate+ , TCR- γδ − , CD3 intermediate+ , CD4 − , CD8 − , Thy1 − , CD5 − , and B220 − . These Mac1 + αβ T cells were not found in other organs such as spleen, thymus, liver, bone marrow and intestine of mice uninfected and infected with Mycobacterium bovis BCG. There was a considerable population of this unusual subset of αβ T cells in the lungs of congenitally athymic nude mice. In the Mac1 + αβ T-cell population, the proportions of Vβ8 + T cells and of forbidden T-cell clones expressing Vβ6 TCR were not much different from that in the conventional T-cell population. These results indicated that extrathymically developed αβ T cells reside in considerable proportions in the lung and that Mac1 clearly discriminates these cells from conventional ones. Interestingly, the proportion of these cells increased in the lungs of mice infected with M. bovis BCG, which raises a possibility that these cells may play some role in the host defense against mycobacterial infection.

Gastrointestinal: Rectal Dieulafoy lesion

A Dieulafoy lesion is a term that is used to describe gastrointestinal bleeding caused by rupture of an exposed submucosal artery associated with a minute mucosal defect. The lesion was originally described by Dr Gallard in 1884 and was subsequently characterized by a French surgeon, Georges Dieulafoy, in 1898. Bleeding from Dieulafoy lesions can occur at any age but is most common in elderly men. The typical site of bleeding is the proximal stomach, usually within 6 cm of the cardio-esophageal junction, but bleeding has been described in a variety of other sites including the esophagus, small bowel and large bowel. Most patients present with intermittent and severe bleeding over several days. When bleeding seems likely to be arising from the large bowel, the initial investigation could be either colonoscopy or mesenteric arteriography. The latter is more likely with torrential bleeding. At colonoscopy, techniques that have been used to control bleeding include epinephrine injections, cauterization, clipping and band ligation. The patient illustrated below was a 76-year-old man who presented with massive rectal bleeding. His medical history included bladder cancer, cecal cancer and a previous cerebral infarct. After resuscitation and a blood transfusion, urgent colonoscopy was performed without bowel preparation. A large amount of fresh blood and clots were noted within the bowel lumen and a bleeding point was not identified. Seven days later, colonoscopy was repeated after a further episode of bleeding. Careful inspection revealed an exposed vessel without surrounding ulceration in the distal rectum consistent with a Dieulafoy lesion (Fig. 1). The vessel was ligated with a single elastic band (Fig. 2). Thereafter, bleeding settled and a follow-up colonoscopy showed that the lesion had healed with scar formation. Although rare, Dieulafoy lesions need to be considered in the differential diagnosis of major rectal bleeding, particularly as they are often suitable for endoscopic therapy.

HLA class-I-restricted and colon-specific cytotoxic T cells from lamina propria lymphocytes of patients with ulcerative colitis.

We established cytotoxic T-lymphocyte (CTL) lines against colonic epithelial cell line from LPLs of patients with ulcerative colitis by continuous stimulation with human lymphocyte antigen A (HLA-A) matched colonic epithelial cell lines and clones from LPLs using polyclonal stimulation with phytohemagglutinin. The established CTL lines and clones showed cytotoxicity against HLA-A-matched colonic epithelial cell line but not against HLA-mismatched colonic epithelial cell lines, and HLA-A-matched lung and esophagus cell lines. The CTL response was HLA class I-restricted and mediated by CD8-positive T-lymphocytes. Moreover, the CTL line showed cytotoxicity against autologous B-LCLs pulsed with peptides extracted from HLA-A-matched colonic epithelial cell line but not against other organ-derived peptides pulsed and unpulsed autologous B-LCLs. CTL lines and clones established from LPLs of patients with ulcerative colitis showed colon-specific and HLA class I-restricted killing of human colonic epithelial cell line, suggesting that these CTLs may play a role in colonic epithelial cell damage in some patients with ulcerative colitis.

Bamboo trees in the stomach

A 46 year old man presented with general fatigue and abdominal discomfort. He had a surgical history of ileal perforation at the age of 40 years. …

Gastrointestinal: Aphthous lesions to overt Crohn's disease

The word aphthous is derived from the Greek word aptha and can be translated as an inflamed spot. The terms aphthous ulcers and aphthous lesions were initially used to describe small superficial ulcers in the mouth but were subsequently used to describe small ulcers in any part of the gastrointestinal tract. Although aphthous lesions have been regarded as early features of Crohn’s disease, they may occur in a variety of other clinical settings including infectious enterocolitis. In Crohn’s disease of the small bowel, aphthous lesions typically occur over Peyer’s patches while in the large bowel, lesions frequently occur over lymphoid aggregates. As the disease progresses, aphthous lesions can enlarge and coalesce, initially forming stellate ulcers and subsequently forming deeper longitudinal and transverse linear ulcers. Islands of mucosa not affected by ulceration can create a cobblestone appearance. The typical endoscopic appearance of an aphthous lesion is a superficial ulcer, 1–5 mm in diameter, with surrounding erythema. Although progression of Crohn’s disease is widely believed to follow the above pattern, radiological documentation of progression is uncommon. The patient illustrated below was a 13-year-old boy who presented with anorectal fistulas. Blood tests revealed mild anemia with an elevated erythrocyte sedimentation rate and C-reactive protein. A double-contrast barium enema study (Fig. 1) showed (Æ) a small number of aphthous lesions in the ascending colon. He was treated with an elemental diet. After an interval of 21 months, he began to lose weight and developed an intermittent fever. A repeat barium enema X-ray (Fig. 2) showed abnormalities in the ascending colon and transverse colon with narrow areas, eccentric rigidity, nodularity and longitudinal ulcers. The appearance was typical of Crohn’s disease.

Gastrointestinal: Duodenal Crohn's disease

Contributed by Drs A Hokama, F Kinjo, R Sugama, K Kobashigawa, R Matayoshi, Y Yonamine, R Tomiyama, T Sunagawa, M Kawane and A Saito, First Department of Internal Medicine, Department of Endoscopy, University of the Ryukyus, 207 Uehara, Nishihara, Okinawa 903–0215, Japan. Contributions to the Images of Interest Section are welcomed and should be submitted to Professor IC RobertsThomson, Department of Gastroenterology, The Queen Elizabeth Hospital, Woodville South, South Australia 5011, Australia.