Bare lymphocyte syndrome (BLS) is a rare immunodeficiency disorder manifested by the
partial or complete disappearance of major histocompatibility complex (MHC) proteins
from the surface of the cells. Based on this specific feature, it is categorized into
three different types depending on which type of MHC protein is affected. These proteins
are mainly involved in generating the effective immune responses by differentiating
'self' from 'non-self' antigens through a process referred to as antigen presentation.
Investigations on BLS have immensely contributed to our understanding of the transcriptional
regulation of these molecules and have led to the discovery of several important proteins
of the antigen presentation pathway. Reviews on this subject consistently project
type II BLS, MHC II deficiency as BLS syndrome, although literatures' document cases
of other types of BLS too. Therefore, in this article, we have assembled information
on the BLS syndrome to produce a systematic narration while emphasizing the importance
of BLS system in studying various aspects of immune biology.
