K. G. M. Park

Stimulation of lymphocyte natural cytotoxicity by L-arginine

In vitro L-arginine enhanced natural-killer (NK) and lymphokine-activated-killer (LAK) cell activity; this cytotoxicity was mediated by CD56+ cells. In vivo arginine supplements (30 g/day for 3 days) increased the number of circulating CD56+ cells by a median of 32% in eight volunteers (p less than 0.01); this increase was associated with a mean rise of 91% in NK cell activity (p = 0.003) and of 58% in LAK cell activity (p = 0.001) in thirteen volunteers. These findings have potentially important implications for the modulation of natural cytotoxicity in a wide range of disease states.

Mucosal changes in the large bowel with endometriosis: A possible cause of misdiagnosis of colitis?

Endometriotic deposits are not uncommon in the large bowel of women. Because the symptoms produced by endometriosis may lead to investigation by colorectal endoscopic biopsy, the aims of this study were to assess the range of mucosal abnormalities that may occur and to determine whether this could represent a significant potential diagnostic problem. We found mucosal changes in eight of 10 cases of colorectal endometriosis; however, the abnormalities (ulceration, gland architectural disturbance, crypt abscess formation, increased inflammatory cell presence, and smooth muscle fibers between glands in the mucosa) were focal and directly related to endometrial deposits. In one case an abnormal colonic biopsy specimen from a patient with endometriosis supported the erroneous clinical diagnosis of Crohns disease. Comparing a group of women with endometriosis to a group with adenomyosis of the uterus showed that although more women with endometriosis have endoscopic large bowel biopsies, there was no significant excess of biopsy specimens showing inflammatory changes. Our conclusion is that the endometriosis of the large bowel can masquerade as inflammatory bowel disease or ischemic changes and the possibility should be borne in mind, particularly in cases with atypical clinical features or very focal histological changes.

Recombinant interleukin-2 treatment in patients with metastatic colorectal cancer: Effect on natural cytotoxicity

SummaryNatural cytotoxicity (natural killer, NK, and lymphokine-activated killer, LAK, activity) was documented in 12 patients with metastatic colorectal cancer, both before and after a 5-day course of continuous therapy with intravenous recombinant interleukin-2 (rIL-2). Treatment induced a substantial increase in circulating CD56+ lymphocytes (pretreatment: 12.1±6.9%, mean ± SD; posttreatment: 39.2±6.9%. Maximal NK cell activity was induced by treatment with rIL-2 but only suboptimal augmentation of LAK cell cytotoxicity was obtained. This study indicates that although continuous infusion of rIL-2 does have a significant effect on natural cytotoxicity, this is suboptimal and further studies are necessary to define the most efficacious immunity-enhancing regimens of therapy, thereby hopefully improving clinical outcome of rIL-2 treatment.