Abstract

This book chapter compiles a general idea of steroids and their overall biological significance in immunity and immune-associated diseases. Steroids chemically comprise a group of cyclical organic compounds constituted by seventeen carbon atoms that consist of four fused rings called sterane, and cyclopentanoperhydrophenanthrene. The four-ringed structures are mainly synthesized by mitochondria and smooth endoplasmic reticulum through the cyclization of thirty-carbon chain squalene into lanosterol or cycloartenol. Steroid hormones differ only in number of oxygen and carbon atoms, but all are derived from cholesterol. The biological significance of steroids and their derivatives range from energy metabolism, and body growth to the control of reproductive activities. However, deficiency or malfunctioning of steroids can lead to direct effects on body salt/sugar levels, sexual differentiation and immunity. As far as immune responses are concerned, a lot of research works have emerged which show the importance of steroids in immune regulation, and in extreme cases, they are also known to result in immune-related diseases. Most of these effects are mediated by the influence of steroids on gene expression in cells and this could in turn prove to be novel drug targets as well. We have made an attempt in this chapter to update and highlight the role of steroids in immune regulation and immune-related diseases, which we hope would open up therapeutic options for diseases.