The emerging role of inorganic elements as potential antigens in sarcoidosis

Abstract

Purpose of reviewPrevious studies mainly described a role for organic agents as possible triggers for sarcoidosis. In this review, we address recent studies suggesting a possible role for inorganic elements, such as metals or silica in sarcoidosis pathogenesis.Recent findingsSeveral epidemiological papers suggest that inorganic agents, either by environmental exposures or occupational activities, could trigger sarcoidosis. Association between inorganics and sarcoidosis is also described in several recently published case reports and studies demonstrating immunological sensitization to inorganic agents in sarcoidosis patients.Studies comparing chronic beryllium disease (CBD) and sarcoidosis suggest that although antigenic triggers may differ, underlying processes may be comparable.Besides the fact that a growing number of studies show a possible role for inorganic triggers, it is also suggested that inorganic triggered sarcoidosis may result in a more severe phenotype, including pulmonary fibrosis.SummaryWe can use the knowledge already gained on CBD pathogenesis to conduct further research into role of inorganics, such as metals and silica as antigens in sarcoidosis. Given the importance of a lymphocyte proliferation test (LPT) in diagnosing CBD, it seems obvious to also implement this test in the diagnostic work-up of sarcoidosis to identify patients with an inorganic antigenic trigger of their disease.

Clinical Manifestations and Management of Fibrotic Pulmonary Sarcoidosis

“…Sarcoidosis is largely believed to result from a culmination of abnormal immunologic responses following antigen exposure ( Figure 1 ) in a genetically predisposed host. Air pollutants, infectious agents such as mycobacteria and Cutibacterium acnes , and exposure to inorganic dust such as silica have been implicated in pulmonary sarcoidosis [ 16 , 17 , 18 , 19 ]. Genetic factors have been implicated in the susceptibility and manifestation of the disease, such as HLA-DRB1 on chromosome 6, 5q11.2, 1p22, 3p21-14, 11p15, and 17q21 [ 5 , 20 , 21 , 22 ].…”

Factors associated with a diagnosis of sarcoidosis among US veterans of Iraq and Afghanistan

“…Both organic and inorganic materials have been found to be associated with sarcoidosis, especially in occupational cohorts 11 . Culprit materials include silica and silicates, metals, dust from the World Trade Center destruction, and wood combustion products identified through epidemiologic investigation and case reports [12][13][14][15] .…”