Functional aspects of cord blood lymphocytes response to polyclonal and allogeneic activation.

With the purpose of contributing to a better knowledge of the phenotypic characteristics and functional activity of umbilical cord blood (UCB) lymphocytes, we have carried out extensive immunophenotyping of these cells, evaluated their immune response to polyclonal and allogeneic activation and then compared these results with those obtained with peripheral blood lymphocytes of healthy donors (PBHD). Our results showed, in CD4+ UCB lymphocytes, an increase of CD38 and CD45RA and a decrease of CD11a (S6F1), CD54 and HLA-DR double positive cells. An increase of CD38, CD45RA and CD56, and a decrease of CD28, CD57 and HLA-DR were observed in CD8+ UCB lymphocytes. Most natural killer UCB cells are CD16+, CD56+, CD57-, and among the UCB cells there is a lower number of CD8+ and TCRgammadelta+ (either CD8- or CD8+), and higher number of CD4+ lymphocytes. After allogeneic stimulus the majority of these phenotypic differences disappeared, which seems to be in agreement with the normal allogeneic response (assessed through MLR, frequency of CTL and helper T lymphocytes precursors) presented by UCB lymphocytes. Regarding the response to polyclonal activation, among the mitogens used, only PHA induced a different result: a lower IFNgamma production by UCB cells.

Relatedness among Basques, Portuguese, Spaniards, and Algerians studied by HLA allelic frequencies and haplotypes.

HLA-A, -B, -DRB1, -DQA1, and DQB1 alleles were studied in Iberian and Algerian populations by serology and DNA sequence methodologies. The genetic and cultural relatedness among Basques, Spaniards, and paleo-North Africans (Berbers or Tamazights) was established. Portuguese people have also maintained a certain degree of cultural and ethnic-specific characteristics since ancient times. The results of the present HLA study in Portuguese populations show that they have features in common with Basques and Spaniards from Madrid: a high frequency of the HLA-haplotypes A29-B44-DR7 (ancient western Europeans), A2-B7-DR15 (ancient Europeans and paleo-North Africans), and A1-B8-DR3 (Europeans) are found as common characteristics. Portuguese and Basques do not show the Mediterranean A33-B14-DR1 haplotype, suggesting a lower admixture with Mediterraneans; Spaniards and Algerians do have this haplotype in a relatively high frequency, indicating a more extensive Mediterranean genetic influence. The paleo-North African haplotype A30-B18-DR3 present in Basques, Algerians, and Spaniards is not found in Portuguese either. The Portuguese have a characteristic unique among world populations: a high frequency of HLA-A25-B18-DR15 and A26-B38-DR13, which may reflect a still detectable founder effect coming from ancient Portuguese, i.e., oestrimnios and conios; Basques and Algerians also show specific haplotypes, A11-B27-DR1 and A2-B35-DR11, respectively, probably showing a relatively lower degree of admixture. A neighbor-joining dendrogram place Basques, Portuguese, Spaniards, and Algerians closer to each other and more separated from other populations. Genetic, cultural, geological, and linguistic evidence also supports the hypothesis that people coming from a fertile Saharan area emigrated towards the north (southern Europe, Mesopotamia, the Mediterranean Islands, and the North African coast) when the climate changed drastically to hotter and drier ca 10 000 years B.C.