One of the most interesting papers on mast cell burden in the GI tract evaluates patients with chronic urticaria. The patients in this study did not have GI symptoms, but they did have skin symptoms related to consumption of trigger foods. Mast cells were identified using antibodies to CD117 and tryptase, and were counted in five hpf and averaged. The healthy controls for this study were from two countries in order to evaluate the effect of diet on mast cell count in healthy patients. There was no difference between the control groups from different countries.
The control group as a whole averaged 20.2 mast cells/hpf in the stomach. The chronic urticaria group as a whole averaged 32.4/hpf in the stomach. This paper also assessed the mast cell count in chronic urticaria patients whose biopsies did not display any tissue damage. In this group, mast cell count averaged 30.4/hpf. In all instances, cells were scattered and not clustered. Mast cell count in CU patients were 61% increased compared to controls. See Table 15 for details.
In the duodenum (small intestine), the healthy control group averaged 32.5 mast cells/hpf. The chronic urticaria group had 44.8/hpf and chronic urticaria patients with normal biopsies (not tissue damage) averaged 45.2/hpf. Again, cells were scattered and not clustered. Mast cell count in CU patients were 37.8% increased compared to controls. See Table 16 for details.
The implication here is that even in the absence of GI symptoms, activation of mast cells in the GI tract might release enough histamine to cause urticaria. An important feature of this paper is that it discusses “pseudoallergens”, which it describes as “non-specific histamine-release” substances. Fourteen of the patients in this study had a history of “pseudoallergen” food triggers that irritated their urticaria. In these patients, mast cell count was actually lower in the stomach than those who didn’t have food “pseudoallergen.” See quote below.
“The skin lesions of CU are caused by vasoactive mediators released through specific or non-specific mast cell degranulation in the skin or elsewhere. CU patients are particularly susceptible to the non-specific histamine-releasing effect of pseudoallergenic substances in various foods and drugs, and the success rate of pseudoallergen-free diets varies between 30 and 50%. It is conceivable that food pseudoallergens induce non-specific mast cell degranulation, rather in the gastrointestinal tract than elsewhere. Activation of many intestinal mast cells may then result in enough histamine release to cause urticaria either directly or indirectly.” (Minnei 2006)
| Table 15: Mast cell count in stomach of patients with chronic urticaria | ||||||
| Minnei F, et al. Chronic urticaria is associated with mast cell infiltration in the gastroduodenal mucosa. Virchows Arch 2006; 448(3): 262-8. | ||||||
| Microscopy method: 400x magnification, counted in 5 hpf and averaged | ||||||
| Visualization: CD117 and tryptase | ||||||
| Sample type | Study group: Chronic urticaria | Study group: Chronic urticaria, biopsies normal | Control group A:
Healthy controls |
|||
| Stomach | Average | Range | Average | Stomach | Average | Range |
| 32.4 mast cells/hpf | 29.5-35.4 mast cells/hpf | 30.4 mast cells/hpf | 26.2-34.6 mast cells/hpf | 20.2 mast cells/hpf | 17.4-22.9 mast cells/hpf | |
| Diffuse scattered cells, no clusters. | Diffuse scattered cells, no clusters. | Diffuse scattered cells, no clusters. | ||||
| Table 16: Mast cell count in small intestine (duodenum) of patients with chronic urticaria | ||||||
| Minnei F, et al. Chronic urticaria is associated with mast cell infiltration in the gastroduodenal mucosa. Virchows Arch 2006; 448(3): 262-8. | ||||||
| Microscopy method: 400x magnification, counted in 5 hpf and averaged | ||||||
| Visualization: CD117 and tryptase | ||||||
| Sample type | Study group: Chronic urticaria | Study group: Chronic urticaria, biopsies normal | Control group A:
Healthy controls |
|||
| Duodenum | Average | Range | Average | Stomach | Average | Range |
| 44.8 mast cells/hpf | 39.2-50.3 mast cells/hpf | 45.2 mast cells/hpf | 38.4-52.1 mast cells/hpf | 32.5 mast cells/hpf | 29.4-35.6 mast cells/hpf | |
| Diffuse scattered cells, no clusters. | Diffuse scattered cells, no clusters. | Diffuse scattered cells, no clusters. | ||||
References:
Jakate S, et al. Mastocytic enterocolitis: Increased mucosal mast cells in chronic intractable diarrhea. Arch Pathol Lab Med 2006; 130 (3): 362-367.
Akhavein AM, et al. Allergic mastocytic gastroenteritis and colitis: An unexplained etiology in chronic abdominal pain and gastrointestinal dysmotility. Gastroenterology Research and Practice (2012): Article ID 950582.
Martinez C, et al. Diarrhoea-predominant irritable bowel syndrome: an organic disorder with structural abnormalities in the jejunal epithelial barrier. Gut 2013; 62: 1160-1168,
Sethi A, et al. Performing colonic mast cell counts in patients with chronic diarrhea of unknown etiology has limited diagnostic use. Arch Pathol Lab Med 2015; 139 (2): 225-232.
Doyle LA, et al. A clinicopathologic study of 24 cases of systemic mastocytosis involving the gastrointestinal tract and assessment of mucosal mast cell density in irritable bowel syndrome and asymptomatic patients. Am J Surg Pathol 2014; 38 (6): 832-843.
Ramsay DB, et al. Mast cells in gastrointestinal disease. Gastroenterology & Hepatology 2010; 6 (12): 772-777.
Zare-Mirzaie A, et al. Analysis of colonic mucosa mast cell count in patients with chronic diarrhea. Saudi J Gatroenterol 2012; 18 (5): 322-326.
Walker MM, et al. Duodenal mastocytosis, eosinophilia and intraepithelial lymphocytosis as possible disease markers in the irritable bowel syndrome and functional dyspepsia. Aliment Pharmacol Ther 2009; 29 (7): 765-773.
Hahn HP, Hornick JL. Immunoreactivity for CD25 in Gastrointestinal Mucosal Mast Cells is Specific for Systemic Mastocytosis. American Journal of Surgical Pathology 2007; 31(11): 1669-1676.
Vivinus-Nebot M, et al. Functional bowel symptoms in quiescent inflammatory bowel diseases : role of epithelial barrier disruption and low-grade inflammation. Gut 2014; 63: 744-752.
Minnei F, et al. Chronic urticaria is associated with mast cell infiltration in the gastroduodenal mucosa. Virchows Arch 2006; 448(3): 262-8.
Hamilton MJ, et al. Mast cell activation syndrome: A newly recognized disorder with systemic clinical manifestations. J Allergy Clin Immunol 2011; 128: 147-152.
Barbara G, et al. Activated mast cells in proximity to colonic nerves correlate with abdominal pain in irritable bowel syndrome. Gastroenterology 2004; 126(3): 693-702.
Guilarte M, et al. Diarrhoea-predominant IBS patients show mast cell activation and hyperplasia in the jejunum. Gut 2007; 56: 203-209.
Dunlop SP, et al. Age related decline in rectal mucosal lymphocytes and mast cells. European Journal of Gastroenterology and Hepatology 2004; 16(10): 1011-1015.
Afrin LB, Molderings GJ. A concise, practical guide to diagnostic assessment for mast cell activation disease. World J Hematol 2014; 3 (1): 1-17.
Molderings GJ, et al. Mast cell activation disease: a concise, practical guide to diagnostic workup and therapeutic options. J Hematol Oncol 2011; 4 (10).
Akin C, et al. Mast cell activation syndrome: proposed diagnostic criteria. J Allergy Clin Immunol 2010; 126 (6): 1099-1104.
Valent P, et al. Definitions, criteria and global classification of mast cell disorders with special reference to mast cell activation syndromes: a consensus proposal. Int Arch Allergy Immunol 2012: 157 (3): 215-225.