Role of immunogenetics polymorphisms in infectious diseases

Genetic polymorphism represents an important characteristic of the system of human biology. The genetic changes/variations greatly influence the human immune system. The process of the immune response generally includes a series of sequential events wherein the complex antigen is subjected to absorption, procession, and presentation to the T helper lymphocytes, activating the suppressor subpopulations, B lymphocytes, and, cytotoxic T cells respectively. Such activities in humans are modulated by highly polymorphic genes, categorized under the major histocompatibility complex (MHC)/human leukocyte antigen (HLA) system. HLA represents a group of a composite gene network, which encodes the MHC-proteins referred to as antigens at the surface of leukocytes. The immune response of the host is activated by the interaction of different products of HLA genes with the surface-specific receptors of the T lymphocytes. The connection of various microbial infections (bacterial, fungal, viral, and parasitic) with the host’s HLA system is broadly explored and the immunogenetic analysis of disease susceptibility has greatly supported the identification of strong HLA links with multiple infections/diseases. In this chapter, we are providing a detailed account of the concept and role of immunogenetic polymorphisms in infectious diseases, their significance in the process of infection in a manner that it will provide meaningful insights into the disease pathogenesis mechanisms and eventually help in the identification of novel molecular/immunogenic targets/strategies. Moreover, we believe that understanding the relationship between immunogenetics polymorphisms and infectious diseases will aid us in improving immunomodulatory therapeutics and the development of improved vaccines against emerging infectious diseases.