An immunogenetic map of Lombardy (Northern Italy)

Abstract

For this study we consulted the Bone Marrow Donors' Registry of Lombardy (Italy) and analyzed 43937 HLA‐A,B phenotypes and 13922 HLA‐A,B,DR phenotypes. We estimated the HLA‐A,B and HLA‐A,B,DR haplotype frequencies via the maximum‐likelihood method. We analyzed the genetic structure of the 11 provinces of Lombardy by means of Principal Component Analysis and Correspondence Analysis, and estimated the variety of the different haplotypes at provincial level and the percentage of unique phenotypes at village level. We found 11189 different HLA‐A,B phenotypes, 661 different HLA‐A,B haplotypes and more than 4000 different HLA‐A,B,DR haplotypes. We identified 20 villages, in Western Lombardy, very rich in unique/rare phenotypes. Here we report a formula which allows the identification of a putative donor matched for two haplotypes with a recipient. This result may be of great importance for the genetic study of the population of Lombardy and, even more, for bone marrow transplantation programs.

Autoimmune stigmata in Turner syndrome: When lacks an X chromosome

“…This is another quite peculiar immunogenetic feature which approaches this syndrome to that of reproductive disorders such as repetitive abortion, pre-eclampsia, preterm delivery, gestosis [30][31][32]. However, when compared with ethnically matched controls, the Turner syndrome cohort appears as a singular population displaying an increased frequency of HLA class I alleles that are rare in our country like HLA-A31 and B38 [12,28,33,34]. Nowadays we know that these alleles and especially B38, mainly in the haplotypic combination with HLA-DRB1 * 13 allele variant, mark florid newborns with high birth weight [35].…”

HLA genes and surnames show a similar genetic structure in Lombardy: Does this reflect part of the history of the region?

“…Out of the Lombardy cluster, Sondrio is associated in the tree with the only other Northern region. According to Martinetti et al (2002), Sondrio has the highest frequency of the haplotype HLA-A2, B51, which was the most frequent in Lombardy, but also has a relatively high frequency of two unusual haplotypes, the HLA-A31, B51, and HLA-A1, B51.…”

“…The HLA-A and -B allele frequencies were calculated from 34,195 unrelated individuals, all healthy blood and/or bone marrow donors. This sample partly overlaps that used by Martinetti et al (2002), as new donors are included and others are excluded, i.e., all individuals in this sample were born and residing in the region, i.e., living in Lombardy for at least two generations. Table 1 shows the data composition in each province.…”

Analysis of the French National Registry of unrelated bone marrow donors, using surnames as a tool for improving geographical localisation of HLA haplotypes

“…In recent years, various national registries of volunteer bone marrow donors have been analysed increasingly often, [1][2][3][4][5][6][7][8] stimulated by the growing number of registered donors, the diversity of their geographical origins and the accuracy of the haplotype definitions in HLA genetic systems. These analyses are also required because of the increasing number of transplants and the need to improve the recruitment of volunteer donors, particularly by identifying the areas where specific donors are most likely to be found and where rare haplotypes occur more often than expected by chance.…”