ABSTRACT
Sarcoidosis is a granulomatous disorder believed to be mediated by T-lympho-
cytes (see chapter 4 ‘‘Mechanism of Granuloma Formation’’, and chapter 5 ‘‘Lymphocytic Aspects’’). The T-cell response in sarcoidosis appears to be a
typical antigen-driven oligoclonal response (see chapter ‘‘Mechanism of Ther-
apy for Sarcoidosis’’). The human leukocyte antigen (HLA) class I and class
II molecules play a necessary role in the T-cell response to antigen. While these
HLA molecules have been recognized for their importance in transplantation,
their critical role in the immune response has only recently become apparent
(1,2). The important role of HLA class 1 and class 2 molecules in the presenta-
tion of antigenic peptides to T-cells, has made these molecules attractive to study the susceptibility to sarcoidosis.
