Expression of MHC Class I, II and CD1 in the Vascular Endothelial Cells and Dermal Inflammatory Cells of Leprosy Skin Lesions

Kim, Seong Hyun; Choi, Hae Young; Hahm, Jeong Hee; Seong, Soon Hee; Ko, Young Hoon

Abstract

BACKGROUND: The recent experimental observations suggested that location of M. leprae in the Schwann cells was mediated by epineurial and endoneurial endothelial cells, giving M. leprae access to the inner compartment of nerves and thus to Schwann cells. CD1 is a family of nonpolymorphic beta2-microglobulin-associated transmembrane glycoproteins that is structurally related to classical MHC Ag-presenting molecules, but is encoded by a separate genetic locus. Recent reports have described that human T cells specifically recognize foreign lipid and glycolipid antigens presented by CD1 proteins. Thus, it appeared likely that CD1 represents the key component of a MHC - independent pathway for antigen presentation to T cells.
OBJECTIVE
we observed expression of antigen presenting molecules, such as MHC class I, II and CD1, in the vascular endothelial cells and inflammatory cells of leprosy skin lesion.
METHODS
MHC class I, II and CD1 expression were studied using immunohistochemical stains.
RESULTS
1. In immunohistochemical stain of HLA-A, B, C, the level of expression in vascular endothelial cells of the borderline tuberculoid leprosy is higher than that of borderline lepromatous leprosy, but lower than that of normal skin tissue. 2. In HLA-A,B,C expression of the inflammatory cells, the level of borderline tuberculoid leprosy is higher than that of borderline lepromatous leprosy and of normal skin tissue(p>0.05). 3. Expression levels of HLA-DP, DQ, DR on endothelial cells decrease significantly in order of normal tissue, borderline tuberculoid leprosy, borderline lepromatous leprosy, lepromatous leprosy(p<0.05). 4. Expression levels of HLA-DP, DQ, DR on inflammatory cells decrease in order of lepromatous leprosy, borderline lepromatous leprosy, borderline tuberculoid leprosy, normal tissue, but statistical significance did not exist. 5. In immunohistochemical stains of CD1b, 3 sections of all 4 normal skin sections and 1 section of 3 borderline tuberculoid leprosy sections showed focal positivity on the dermal inflammtory cells, but borderline lepromatous leprosy sections did not show any positive inflammatory cells. 6. Epidermal Langerhans cells showed positivity on immunohistochemical stains of CD1a and CD1b.
CONCLUSION
These results suggest that expression of MHC class I and II on the vascular endothelial cells and expression of CD1b on the inflammatory cells decrease in order of immunity of lepromatous skin lesion and that vascular enothelial cells play an important role in the pathogenesis of leprosy.