The human leukocyte antigen (HLA) system is a highly polymorphic gene complex which has an essential role in immune response activation and in self and non-self discrimination. HLA molecules influence the immune response to pathogens, are involved in disease susceptibility, in autoimmunity and in transplant engraftment (histocompatibility). Analysis of HLA gene polymorphism HLA can be used in to characterize individuals and populations and is useful for anthropological studies to shed light on the genetic relationships between populations from different origins. The use of SBT (sequencing based typing) method permits the exact allele assignment, being able to also identify new variants.
. In a clinical context, a knowledge of the allele frequency distributions in various populations is critical to the strategy of searching bone marrow donors as well as in studies of HLA-associated disease susceptibility.
The aim of the present study has been to characterize the HLA genetic diversity in two geographically and linguistically different ethnical groups from Morocco, never typed before.
The main activities of the Institute, in its section of L'Aquila, are in the histocompatibility field. Since 1999 the Institute collaborates with the Laboratoire d'Immunologie of the Institut National d'Hygiene of Rabat, Morocco, at first within an International Project of scientific cooperation CNR/CNCPRST. During 2002, part of the results of the study of HLA class I and II polymorphism in two ethnical groups from Morocco have been analysed and presented within the 13th International Histocompatibility Workshop (HLA 2002 Book IHW, in press). The modern Moroccan people demonstrate great heterogeneity because of the colonization and immigration events experienced during its history. The Berber population has an ancient origin and represents the autochthonous basis of the Moroccan population. The Arabic-speaking populations mainly live in the North and the Atlantic coast. HLA-DRB1 (Human Immunol. 63,129-138, 2002), HLA-A, -B and -Cw allele frequencies have been assessed using direct sequencing in Metalsa (Berbers from the North, Nador region) and Chaouya (Arabic-speaking from the Atlantic Coast, Settat region) groups and results have been compared with the allele frequencies of other North African and Mediterranean populations. Each group exhibited some specific variants and some uncommon alleles, and two novel alleles, HLA-B*570302 e A*3010, have been assigned. The inter-population analysis highlighted a strong relatedness, based on genetic distances, between the two Moroccan groups and the other north Africans, and to a lesser extent with the Iberians, French, and Ethiopians. This study has defined the HLA profile in Morocco taking into account two distinct ethnical groups and employing the most accurate typing techniques; it could represent a useful background for clinical typing in a Mediterranean Country, like Morocco, which is starting the development of clinical transplant programs, and in which, because of the prevalence of some disease, mainly infective diseases, the study of HLA-associated disease susceptibility could be particularly interesting.
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