Productive (or proliferative) inflammation is a reaction of the body. When the appearance of which a particular phase prevails. That is, in this case, cell proliferation of histiogenic and hematogenous origin prevails. The main cell in the area of productive inflammation is considered to be a monocyte entering the tissue directly from the bloodstream; in the tissues, the monocyte is transformed into a macrophage.
Macrophage
The main function of the macrophage is phagocytosis. On its surface there are many different receptors that are necessary for the capture of viruses, fungi, bacteria, immunoglobulins. Phagocytosis during proliferative inflammation cannot always be completed, that is, it does not end with the absolute digestion of a foreign agent. Viruses and microbial cells inside macrophages survive, multiply, which is why the process takes on a chronic form. In addition to macrophages, other cells are often found during proliferative inflammation. These include lymphocytes, eosinophils, plasma cells, mast cells, single neutrophils.
During cell proliferation, diffuse or focal infiltrates form.
Varieties
The problem can develop in any organ of the body and on any tissue. The following types of proliferative inflammation are distinguished:
- interstitial (interstitial);
- productive with the formation of polyps, genital warts;
- granulomatous.
Let's consider them separately.
Interstitial
Interstitial (or interstitial) is a type of proliferative inflammation in which a diffuse or focal cellular inflammatory infiltrate is formed in the stroma of the heart, liver, kidneys, lungs. Infiltrate is represented by lymphocytes, plasma cells, macrophages, eosinophils, single mast cells, elements of a destroyed parenchyma, rare neutrophils.
In parenchymal elements, pronounced dystrophic, in some cases necrobiotic, changes are determined. The result of interstitial inflammation will be interstitial fibrosis, which is an overgrowth of connective tissue.
With polyps and genital warts
The proliferative phase of inflammation with the formation of polyps, as well as genital warts, is characterized by a chronic course. It is localized on the mucous membrane. Separate sections of hyperplasia are formed on the mucous membranes of different organs, as well as epithelial growths in the form of polyps, in which the connective tissue base is infiltrated by macrophages, lymphocytes, plasma cells and others.
It is localized most often on the mucous membrane of the nose, stomach, uterus, intestines, bronchi. In the case of localization of inflammation at the junction of a single-layer cylindrical and stratified squamous epithelium, the so-called condylomas form. These formations often appear in the anus, as well as on the genitals. In chronic proliferative inflammation, frequent condyloma is genital, which is caused by papillomavirus. It is considered a risk factor for the development of squamous cell carcinoma.
Granulomatous
Granulomatous is another option for productive (proliferative) inflammation. During which granuloma is considered the main morphological substrate, where cells prevail: macrophages, as well as their derivatives (giant cells, epithelioid).
Granuloma morphogenesis has four consecutive phases. These include the following:
- accumulation of young monocytes in the lesion;
- maturation of these cells in a macrophage with the formation of macrophage granulomas;
- further maturation and conversion of monocytes and macrophages into an epithelioid cell and the formation of epithelioid cell granulomas;
- transformation of the epithelioid cell into a giant Pirogov-Langhans cell (foreign body cell) and the formation of giant cell granulomas.
It should be noted that the phagocytic activity of a granuloma cell gradually decreases as it matures.
The diameter of the granulomas is about 1-2 mm, most often they are visible only with a microscope. In the central region of the granuloma, tissue detritus can be seen, which is formed as a result of tissue necrosis and in which the causative agent of the underlying disease can be detected, if in this case there is an infectious process. Macrophages are located on the periphery of necrosis. Also, there are giant, epithelioid cells, among them there may also be plasma cells, neutrophils, lymphocytes, eosinophils.
Granulomatous diseases
Among such diseases, in the form of proliferative inflammation, 4 groups are distinguished. These include:
- infectious etiology, which should include rheumatism, rash and typhoid, rabies, brucellosis, tularemia, viral encephalitis, yersineosis, actinomycosis, syphilis, leprosy, schistosomiasis, tuberculosis, scleroma, glanders and others;
- non-infectious etiology, which should include gout, silicosis, anthracosis, talcosis, asbestosis, berylliosis, aluminum;
- medical ailments, for example, drug hepatitis, oleogranulomatous disease;
- diseases of unknown etiology: Crohn's disease, sarcoidosis, Horton's disease, Wegener's granulomatosis, rheumatoid arthritis, xanthogranulomatous pyelonephritis.
Absolutely all granulomas have an infectious etiology, despite the differences, in morphology they are similar to each other. It is also worth noting that in all situations, infectious granulomas appear as clusters of cells of a monocytic-macrophage nature. In some granulomas, lymphocytes, neutrophils, plasma cells are formed, with helminthiases, many eosinophils appear.
The only exceptions are granulomas in case of tuberculosis, syphilis, scleromas, glanders, leprosy. In these diseases with proliferative inflammation, these granulomas have specific features that are characteristic of only a specific pathogen. And this allows us to attribute this group of diseases to the group of specific granulomatoses. Or a specific inflammation.
In the morphological concept, the formation of several specific granulomas will be characteristic of a specific inflammation. Which have a characteristic structure. It may differ depending on the main pathogen - the causes of proliferative inflammation. Thus, the cellular composition, as well as the location of cells directly in the granuloma, is quite specific for each pathogen.
With tuberculosis
The inflammatory process in tuberculosis, that is, mycobacterium tuberculosis, can cause three types of tissue reaction: exudative, alternative, and proliferative.
As for alternative inflammation, it often develops as a result of hypoergy, in the case of a decrease in the protective forces of the human body. This inflammation is manifested morphologically by caseous necrosis.
Exudative type of inflammation develops as a result of existing hyperergy (in case of hypersensitivity to toxins of mycobacteria, antigens). Morphologically, the accumulation is manifested in the lesion of fibrinous, serous or mixed exudate, which later also undergoes caseous necrosis.
Proliferative inflammation, pathological anatomy says, develops in the condition of a specific tuberculous immune system. The morphological manifestation in this case will be the formation of the so-called tuberculous granulomas, presented in the form of millet grain.
Tuberculosis granuloma
So, we examined what is characterized by proliferative inflammation. Now it is worthwhile to separately consider some cases in which it manifests itself.
Tuberculous granuloma has a characteristic structure: in its central region there is a focus of the so-called caseous necrosis, behind which there is a shaft of radially localized (that is, elongated along the periphery from the center) epithelioid cells. Behind these cells, giant single Pirogov-Langhans cells are visible.
It should also be noted that at the periphery of such a granuloma there is a shaft of lymphocytes. In a large number of these typical cells, plasma cells, as well as macrophages, can be detected in a small amount. In addition, a thin network consisting of argyrophilic fibers is revealed here. As for blood vessels, they are not found here. In the case of Ziehl-Nielsen staining, mycobacterium tuberculosis can be detected in these giant cells.
The inflammatory process in syphilis
The inflammatory process with syphilis at different periods will reflect a different tissue reaction to pale treponema: as a rule, primary, secondary, and also tertiary periods in case of syphilis are distinguished.
In the case of primary syphilis, the so-called productive-infiltrative reaction develops in the area of the introduction of treponema.
During the secondary, a strongly expressed exudative reaction is observed, contributing to the generalization of the pathogen,
In the case of a tertiary period of syphilis, a productive necrotic reaction will be presented in the form of syphilitic granulomas, as well as gummy infiltrates.
More About Syphilitic Granuloma
Syphilitic granuloma in the field of medicine also bears the short name “gumma”. In this granuloma, as in the case of tuberculosis, caseous necrosis is found in the center, but in this situation it will be larger in size.
From peripheral necrosis there is a large number of lymphocytes, fibroblasts, as well as plasma cells. In small quantities, macrophages, giant cells, and epithelioid cells can be present here. In this case, the proliferation of connective tissues is considered characteristic (this is due to the speed of fibroblast proliferation), which form a kind of capsule, as well as a large number of blood vessels.
Quite rarely, among these cells, specialists are able to identify the so-called pale treponema by the Levaditi silvering method. Gum is characteristic for the tertiary period of syphilis, which begins to develop in a few years (5 or more) from the time of its infection.
In various organs: skin, liver, bones, and brain, nodes are formed over a period of one decade, measuring 0.3-1.0 cm in diameter. In the context of these nodes, a certain jelly-like mass of a yellowish tint stands out, which in its appearance resembles gum arabic glue, whence the name “gum” came from.
Gummous infiltration
In addition to these gummies, in the tertiary period of syphilis disease, gummous infiltration can also develop. Infiltration is represented by the same cells, that is, sclerosis, vascular proliferation. Infiltrate is most often localized in the ascending part of the heart, as well as the aortic arch, and is called "syphilitic mesoaortitis."
It, located in the central and outer membrane of the cardiac aorta, gradually destroys its elastic frame, and in place of elastic fibers, connective tissue begins to grow. For the reason of all this, the inner lining on the aorta becomes uneven and wrinkled with a large number of cicatricial retracts, bulges, resembling a shagreen skin.
Conclusion
As we previously noted, proliferative (or productive) inflammation is distinguished by cell proliferation. Exudative and alterative changes recede only into the background. The entire course of this inflammatory process can be acute, however, most often - chronic.