The etiology and pathogenesis of Crohn's disease

Etiology of Crohn's disease is so far not known. Detection under a microscope among cells items granulomas in Crohn's disease giant cells gave rise to the discussion of tuberculosis etiology of the disease. However, none of the researchers failed to allocate the tuberculosis bacteria from the feces of these cases, as well as from the intestinal wall of affected areas. With the introduction of intestinal extracts Guinea pigs were received negative results. Antibacterial anti-TB therapy has proven to be ineffective in Crohn's disease. Microscopic examination granulomas were no caseous necrosis, so characteristic of tuberculosis.
At the present time should not put an equal sign between Crohn's disease, sarcoidosis Beck, although the microscopic picture of granulomas in these diseases is of the same type.
Crohn and Garnis (1958) assumed viral origin of Crohn's disease. Recently McGill (1968) issued a statement, in which once again discussed the infectious nature of this disease and as a possible pathogen considered mycobacteria. The latter is unable to allocate neither crops nor on special media. According to the author, the injured tissue ulcers causes of autoimmune reactions, and then joins the secondary infection. However, Wright and Truelove (1965), Harrison (1965) were observed in Crohn's disease pathological autoantibodies, which casts doubt on the value of autoimmune disorders in these patients.
While there is no direct evidence of an allergic nature of the disease.
Soltoft (1969) using immunofluorescence established normal value immunoglobulinami cells with prevalence of IgA in the mucosa of the jejunum. Only the total number of fluorescent cells was increased, indicating a significant prevalence of pathological process.
Apparently, the origin of Crohn's disease some importance genetic factors. This is proved by the existence of family forms of Crohn's disease (Sherlock and others, 1963; Almy and Sherlock, 1966), and the same type of intestinal damage in identical twins. According to Hislop and Grant (1969), the disease is inherited through a dominant gene, it is possible genetic predisposition, which can occur only under the influence of some external factors.
Crohn's disease is characterized by histological findings lymphatic swelling in the submucosal layer intestine, which can be caused by a violation of lymph drainage.
Ammann (1959-1964) on the basis of own experimental work has formulated "lymph" the theory of the origin of Crohn's disease, according to which the pathological agent unclear nature affects mesenteric lymph nodes, they hyperplasias, disrupted the flow of lymph with the appearance of edema in the submucosal layer, and then there are destructive changes in the mucous membrane with the formation of necrosis and ulceration. Amid swelling rapidly developing cellular infiltration and granulomas. This theory does not have widespread support, as in many cases there was no evidence of increased mesenteric lymph nodes.
Crohn (1967) discusses the different forms of Crohn's disease as a result of exposure to the virus, or other unknown etiological factor. This is the response of the intestinal wall can be different in different segments of the gastrointestinal tract. The most frequently affected the final ileum, as the permeability of the intestinal epithelium in this area is greatest; in addition, the chyme in bauhinias flaps, of course, is delayed.
According to Crohn, the reaction of the intestine "virus" appears massive proliferation of granulation tissue in order to limit the spread of the agent into the depths. Such "delimitation" is usually insufficient, and inflammatory changes cover the intestinal wall in toto, there are internal and external fistula. The mechanism of development of pathological changes in the other parts of the digestive system is similar, but their depth and prevalence may be different.
Bockus (1964) argues that many etiological factors cause the same type of morphological changes in the intestine in individuals with a certain predisposition to Crohn's disease. These agents contribute to the emergence in some areas of the intestine increased tissue sensitivity with high reactivity. Tissue reaction obviously includes the lymph system of the intestine and mesentery in General.
Thus, while there is no single generally accepted view of the origin of Crohn's disease. Many researchers believe that the Central part of the pathogenesis of the last remains of the lymph system with secondary involvement in the pathological process of the intestinal wall and development of granulomatous inflammation other tissue changes. To determine the causes of these violations further research is needed.