title: The Indian blood group system.
abstract: The Indian blood group system (ISBT: IN/023) consists of two antithetical antigens: In(a) (IN1), which is present in approximately 10 percent of some Arab populations and in 3 percent of Bombay Indians, and its allelic antigen In(b) (IN2), an antigen of high incidence in all populations. In 2007, two new high-incidence antigens were identified as belonging to the IN blood group system, namely IN3 (INFI) and IN4 (INJA). The antigens in this system are located on CD44, a single-pass membrane glycoprotein that is encoded by the CD44 gene on chromosome 11 at position p13. The biologic function of CD44 is as a leukocyte homing receptor and cellular adhesion molecule. The In(a) and In(b) polymorphism represents a 252G>C substitution of CD44, encoding R46P, and lack of IN3 and IN4 results from homozygosity for mutations encoding H85Q and T163R in the CD44 gene. The high-frequency antigen AnWj (901009) has not been assigned to the Indian system, but either is located on an isoform of CD44 or is closely associated with it.
authors.affiliation: Blood Group Reference and Research Laboratory, Shandong Blood Centre, 22 Shanshi Eastroad, Jinan 250014, Shandong Province, P.R. China.
authors.forename: Q
authors.initials: Q
authors.lastname: Xu
mesh_terms: D000743:Anemia, Hemolytic / Q000453:epidemiology / Q000209:etiology* / Q000517:prevention & control; D000906:Antibodies / Q000378:metabolism; D001789:Blood Group Antigens / Q000235:genetics / Q000276:immunology / Q000378:metabolism*; D001803:Blood Transfusion; D004912:Erythrocytes / Q000276:immunology / Q000378:metabolism* / Q000473:pathology; D005006:Ethnicity; D005787:Gene Frequency; D006801:Humans; D018960:Hyaluronan Receptors / Q000235:genetics / Q000276:immunology / Q000378:metabolism*; D011110:Polymorphism, Genetic; D011183:Postoperative Complications / Q000276:immunology*; D016201:Receptors, Lymphocyte Homing / Q000276:immunology
chemical_list: D000906:Antibodies; D001789:Blood Group Antigens; D018960:Hyaluronan Receptors; D016201:Receptors, Lymphocyte Homing