Sarkoidoz, part I: classification, etiology, clinic

Sarkoidoz, part I: classification, etiology, clinicSarkoidoz (from Greek sarx, sarcos – meat, a flesh + eidos – a look) – the polysystem disease of an unknown etiology relating on the morphological features to group гранулематозов.

Historical background
The first mention about саркоидозе skin (so-called papillyarny psoriasis) belongs to 1869 (J.Hutchinson). In 1889 of E. Besnier also described skin defeat at the patient after freezing injury of fingers, having called it is lupus pernio. In 1899 of C. Boeck applied for the first time the term «саркоидоз skin», being based on external similarity of changes of skin to those at sarcoma. In 1917 of J. Schaumann united everything the cases of an illness described earlier including defeat of various groups of lymph nodes under one term – «good-quality лимфогранулема». For a long time the eponimichesky term «Benye-Beka-Shaumanna illness» was applied to designation of this disease, having a wide circulation in classical German and French medical literature while in 1948 at the international conference in Washington the term "sarkoidoz" which has entered into the international classification of diseases was not accepted.

Epidemiology
Sarkoidoz is widespread around the world, mainly in belts with a temperate and frigid climate. In all industrialized countries the increase in number of patients is noted. According to the generalized statistical data, prevalence саркоидоза in the world makes about 20 on 100 000 population (in the USA and Europe on the average from 10 to 40). At carrying out large-scale radiological skriningovy researches the following indicators of prevalence саркоидоза on 100 000 inhabitants [1] are defined: in Sweden – 64, – 19 (however among the Irish women living in London – 200 on 100 000) and this figure steadily grows in England at the expense of immigrants from India, Iran and other Asian countries [2]. Incidence in Denmark, Norway, Finland – 8-17; Holland, Belgium, Poland, England, Switzerland, Lithuania, the Czech Republic and Slovakia – 2-8; Italy, Spain, Portugal, Yugoslavia – 1-2 [3]. Sarkoidoz extremely seldom meets among the Canadian Indians, Eskimos in New Zealand and South East Asia. It is noted that in economically and socially safe countries the number of patients annually increases by 1,9 % (while patients with tuberculosis decreases by 5 %).

The illness meets at persons of both floors and almost all age. Small prevalence of women (53 %) is noted. The incidence peak (80 %) is the share of one of the most active age periods – 20-40 years.

Classification
In 1958 of K.Wurm and соавт. [4]] offered radiological classification саркоидоза which despite numerous attempts of modifying remains to the most widespread, and not least because of the simplicity:

I. A stage – a sredosteniye limfadenopatiya.
II. A stage – ochagovy blackouts of a pulmonary fabric, it is frequent against the strengthened pulmonary drawing. Has 4 podstadiya:
IIA. Strengthening and mesh deformation of pulmonary drawing.
IIB. Widespread bilateral melkoochagovy changes in lungs (0,5-2,5 mm).
IIB. Widespread bilateral sredneochagovy changes in lungs (2,5-5 mm).
IIG. Widespread bilateral krupnoochagovy changes in lungs (more than 5 mm).
III. Widespread interstitsialny фиброз pulmonary fabric.
Allocate also the IV stage саркоидоза to which refer system manifestations.

Etiology
The etiology саркоидоза remains to the unknown. For many years in literature the concept of «a special form of tuberculosis», still having numerous supporters, and mainly in our country dominated. Nevertheless, unequivocally to argue that саркоидоз этиологически it is independent of tuberculosis, it is impossible. At supervision and treatment of patients sarkoidozy in antitubercular establishments frequency of spontaneous remissions made 6,9-12 % [5], whereas when maintaining such patients in the conditions of the versatile noninfectious medical center in the Netherlands – to 93,3 % that testifies in favor of the importance of a mikobakteriya (probably as the trigger) in патогенезе саркоидоза. From 50-70th саркоидоз it began to be considered as the independent nosological form caused by the unknown agent. Now the majority of scientists holds the opinion about a polietiologichnost of this disease.

About 30 % of the diseased have professional contact to various chemicals (pairs of acids, alkalis, paints, acetone and other solvents, plastic, cement, etc.). There are instructions on a number of the factors which are probably taking part in emergence and development саркоидоза: pine pollen, beryllium, zirconium, сульфаниламиды, methotrexate, etc. Searches of arguments in favor of a bacterial, virus, fungoid, parasitic etiology саркоидоза proceed.

These roles of the genetic device in disease development collect. Cases family саркоидоза are known, the illness can be observed at twins (more often at monogerminal, than at dizygotic pairs). At HLA A1-B8 carriers саркоидоз it is shown knotty eritemy, artralgiya, uveity while at HLA B13 carriers – proceeds chronically more often authentically more often. Nevertheless scientifically proved risk factors of this disease are absent now.

Patogenez
Development at саркоидозе granulomas of immune type (that is a consequence of an imbalance of subpopulations of immunoregulatory cages and weakening of the T-cellular link of immunity) testifies in favor of the assumption that саркоидоз grows out of immunological violations owing to impact on an organism of various factors of the ekzogenny origin changing the immune status, or growing out of the primary changed immune status.

The initial stage which leads over time to damage паренхимы lungs is the congestion of inflammatory and immune cages in bodies and fabrics. In lungs the key role is allocated for the alveolar macrophages (AM) participating both in inductive, and in an effektorny phase of the immune answer. AM produce the factor of growth stimulating a proliferatsiya фибробластов and V-lymphocytes, and also IL1 involving in the center of an inflammation T-lymphocytes. In turn, T-lymphocytes produce IL2 (stimulates a proliferatsiya of T-cages, a differentiation in effektorny cages, attraction in CD4 blood-groove +), biologically active substances: a hemotoksichesky factor for monocytes, factors of growth and a differentiation of V-lymphocytes, ?-интерферон. IL1 synthesized by activated macrophages, is also capable to stimulate T-lymphocytes that leads to short circuit of the vicious circle and maintenance of immune inflammatory reaction. Realization of increase of immunological activity at organ level leads to formation of three interconnected (though not obligatory for the specific patient) stages: a lymphocytic infiltratsiya (альвеолит) – an epitelioidno-cellular granuloma (гранулематоз) – фиброз.

Pathological anatomy
The basis of the morphological characteristic саркоидоза is made by the stamped granulomas containing individual cages Pirogova-Langkhansa. The central part of a granuloma consists of epitelioidny and huge cages, peripheral – form mainly lymphocytes, макрофаги, to a lesser extent pl
asmatic cages, фибробласты. All listed cages are at early stages of a differentiation. The Kazeozny necrosis in the center of sarkoidny granulomas – is not characteristic, though is possible.

The granulomas defined at саркоидозе, have similar lines with tubercular, mikotichesky, туберкулемами at ekzogenny allergic альвеолите (EAA), sarkoidny ангиите easy (SAL). It is most difficult to differentiate sarkoidny granulomas and granulomas of a tubercular etiology with a kazeozny necrosis in the center. At саркоидозе sometimes come to light hyaline, and at tuberculosis – kazeozny necroses. Mycosis can be distinguished serologichesky and microbiological methods. At EAA of a granuloma have certain differences (see табл 1). On the structure of a granuloma at sarkoidny ангиите lungs (the meeting disease is the extremely rare) remind sarkoidny, however are less accurately outlined, huge cages of the smaller sizes. In the largest granulomas necrosis sites in the center are found. The main distinctive feature – localization of granulomas at SAL (walls of pulmonary arteries, veins) and a diffuzny infiltratsiya lymphocytes of separate sites of vessels and an okolososudisty fabric.

Also sarkoidopodobny granulomas (so-called sarkoidny reaction), in easy, lymph nodes and other bodies can be defined at infectious diseases (A tulyaremiya, salmonellosis, a tsitomegalovirusny infection, Ku fever, syphilis, листериоз), гистиоплазмозе, кокциодиоидозе, candidiasis, актиномикозе, parasitic diseases (аскаридоз, амебиаз, шистосомозы, анкилостомоз), consequences of immunological abberatsiya, a medicinal illness, an illness Krone, ulcer colitis, primary biliarny cirrhosis, rheumatic fever, HIV, лимфогранулематозе, гистиоцитозе X, гранулематозе Wegener, defects of fermental systems, new growths, impact on an organism of chemicals (beryllium, starch, silicone, the silicon, some medicines).

Attracts attention lack of overlapping between expressiveness of morphological changes and clinical manifestations саркоидоза, and also expressiveness of the last and radiological changes.

Table 1 Differential diagnostics Sarkoidnykh and EAA of granulomas.

Sign

Sarkoidoz

ЭАА

Form

Correct form

Wrong form

Borders

The accurate

The indistinct

Current

Rather stable

Disappearance of h / з some months after the termination of contact to an anti-gene

Arrangement

In an interstitsialny fabric of lungs, a podslizisty layer of large bronchial tubes peri/intravaskulyarno

To. the item in an interstitsialny fabric of lungs

Character of an infiltratsiya

Lymphocytes, plasmatic cages only round granulomas

Such regularity is absent

Sarkoidoz, part II: Clinic, Diagnostics, Treatment.>>>

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