Introduction

Sarcoidosis is a systemic disease that involves many immune pathways. It is believed that granuloma formations result from an exaggerated immune response to unknown antigens.^1-3

• Granulomas are typically composed of macrophages, epithelioid cells, multinucleated giant cells, T cells, mast cells, and fibroblasts^1-3
• Various cytokines, such as IL-2, IFN-gamma, and TNF-alpha, are released throughout the process, leading to sarcoid granuloma formation, inflammation, and progression^1-3
• B cells may be directly involved in local inflammatory processes in granulomatous tissue in patients with sarcoidosis⁴
• Serum BAFF levels were significantly elevated in sarcoidosis patients when compared with healthy controls^5,6

Hypothesized Immunopathagens of Sarcoidosis³

Sarcoidal granulomas may persist, resolve, or lead to fibrosis³

APCs=antigen-presenting cells. BAFF=B-cell activating factor. GM-CSF=granulocyte-macrophage colony-stimulating factor. IFN=interferon. IL=interleukin. TNF=tumor necrosis factor.

References

1. Baughman RP, Culver DA, Judson MA. A concise review of pulmonary sarcoidosis. Am J Respir Crit Care Med. 2011;183(5):573-581.
2. Gerke AK, Hunninghake G. The immunology of sarcoidosis. Clin Chest Med. 2008;29(3):379-390.
3. Iannuzzi MC, Rybicki BA, Teirstein AS. Sarcoidosis. N Engl J Med. 2007;357(21):2153-2165.
4. Kamphius LS, van Zelm MC, Lam KH, et al. Perigranuloma localization and abnormal maturation of B cells: emerging key players in sarcoidosis? Am J Respir Crit Care Med. 2013;187(4):406-416.
5. Saussine A, Tazi A, Feuillet S, et al. Active chronic sarcoidosis is characterized by increased transitional blood B cells, increased IL-10-producing regulatory B cells and high BAFF levels. PLoS One. 2012;7(8):e43588.
6. Ueda-Hayakawa I, Tanimura H, Osawa M, et al. Elevated serum BAFF levels in patients with sarcoidosis: association with disease activity. Rheumatology (Oxford). 2013;52(9):1658-1666