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Ulcerative colitis: causes
Last reviewed: 23.04.2024
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For decades, intensive search for common mechanisms of development common to one of these diseases has been carried out.
The most interesting is the infectious theory. And this is quite understandable, since the inflammatory nature of ulcerative colitis gave reason to assume that a certain causative agent is involved in the onset and development of the pathological process. The opinion was expressed that the cause of ulcerative colitis can be caused by viruses, bacteria or products of their vital activity. In later works, L-forms of small-bowel bacteria (Chlamidia, Str. Faecalis) were considered as a causative agent of ulcerative colitis. Currently, research in this direction continues, but so far attempts to identify a particular pathogen have not been successful.
Chronic course of nonspecific ulcerative colitis, a tendency to seasonal exacerbations, severe systemic manifestations, a positive effect of hormonal therapy suggested the participation of immune mechanisms in the development of these diseases. In this regard, the immune status of patients has been repeatedly studied. Clinico-immunological comparisons were conducted, which showed that with increasing severity of the process in the gastrointestinal tract, the changes in the immunological status are aggravated. Local changes in subclasses of IgA in case of nonspecific ulcerative colitis with localization of the process in the colon have been revealed. The assumption of participation in the pathophysiological mechanisms of both diseases of endotoxins led to a study to determine the serum antibodies lipid A (ALA), which is a component of endotoxins of gram-negative bacteria.
Analysis of literature data shows that, for all the complexity and versatility of studies on the immunological status of patients with ulcerative colitis, the authors seek to find an answer to three main questions:
- whether immunological mechanisms participate in the occurrence and development of these diseases;
- can autoimmune reactions that occur in the process of ulcerative colitis give a clue to understanding the causes of these diseases;
- whether the immunological factors influence certain groups of people, making them susceptible to ulcerative colitis.
In order to obtain an answer to the question, non-specific ulcerative colitis is not a classic genetic disease, the HLA phenotypes were studied in patients, their relatives and control group. The obtained results confirmed the data of previous studies that ulcerative colitis can not be attributed to typical genetic diseases.
Thus, despite numerous studies of various genetic, immunological, microbial and psychogenic factors, as well as environmental factors, the cause of nonspecific ulcerative colitis has not yet been established. It is unclear whether these diseases are various nosological forms or whether they represent different manifestations of the same disease. Apparently, in the multifactor model of their etiology and pathogenesis, all of the above factors can be important. The most widely accepted theory of the origin of nonspecific ulcerative colitis indicates the leading role of intestinal antigens, whose effects are accompanied by changes in immune reactivity and inflammation of the intestine. It is assumed that the reactivity of the organism is also affected by the still little studied genetic factors.
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