Lähettäjä: Soijuv Lähetetty: 19.1.2005 8:42
Sarkoidoosin etiologia on selvittämättä. Yhtenä mahdollisena syynä on epäilty erilaisia mikrobeja kuten borreliabakteeria ym. borrelioosia sairastavilla usein esiintyviä taudinaiheuttajia kuten cytomegalovirus ja mykoplasma:
Pathophysiology: The etiology of sarcoidosis is unknown, but several immune aberrations have been noted and are thought to play a role in its pathogenesis.
Studies have shown an increase in B-cell activity with hypergammaglobulinemia noted in about one half of patients and in nonspecific immune-complex formation. Reduced delayed-type hypersensitivity responses are also found in many patients with sarcoidosis. Cutaneous anergy to tuberculin intradermal testing occurs in two thirds of patients. Immune dysregulation has been theorized to be due to a persistent antigen of low virulence that is poorly cleared by the immune system, leading to a chronic T cell of the Th1 subtype response, which results in granuloma formation.
Proposed antigens fall into 3 categories that include infectious, environmental, and autoantigens.
The most common infectious agents implicated are Mycobacterium tuberculosis, Mycoplasma species, Corynebacteria species, spirochetes, atypical mycobacteria, Propionibacterium acnes, Borrelia burgdorferi, herpes simplex virus, Epstein-Barr virus, cytomegalovirus, coxsackievirus, rubella virus, Histoplasma species, Cryptococcus species, coccidioidomycosis, and sporotrichosis.
Environmental antigens implicated include metals (eg, zirconium, aluminum, beryllium), organic dusts (eg, pine, pollen), and inorganic dusts (eg, clay, soil, talc). Heat shock protein has also been implicated.