Advancing allele group-specific amplification of the complete HLA-C gene--isolation of novel alleles from three allele groups (C*04, C*07 and C*08)

A variety of strategies have been designed for sequence-based HLA typing (SBT) and for the isolation of new human leucocyte antigen (HLA) alleles, but unambiguous characterization of complete genomic sequences remains a challenge. We recently reported a simple method for the group-specific amplification (GSA) and sequencing of a full-length C*04 genomic sequence in isolation from the accompanying allele. Here we build on this strategy and present homologous methods that enable the isolation of HLA-C alleles belonging to another two allele groups. Using this approach, which can be applied to sequence-based typing in some clinical settings, we have successfully characterized three novel HLA-C alleles (C*04:128, C*07:01:01:02, and C*08:62).

Costimulatory molecules and cytokine production by T lymphocytes in common variable immunodeficiency disease

Common variable immunodeficiency (CVID) is a heterogeneous syndrome characterized by hypogammaglobulinaemia and recurrent infections. Although early works pointed to a primary B-lymphocyte defect as a cause of the disease, a failure in T-lymphocyte cooperation has also been suggested. T cells exert their costimulatory function through either membrane costimulatory molecules or secreted cytokines, both having an influence in the development of the humoral response. The aim of our study was to evaluate whether an abnormal expression and induction of costimulatory molecules or alterations in the production of cytokines by T cells cause deficient T/B cooperation in CVID patients. We studied the expression and upregulation of costimulatory molecules (CD28, CD40L/CD154 and CTLA-4/CD152) and production of cytokines (IL-2, IL-4, IL-6, IL-10, IFN-gamma and TNF-alpha) in purified T lymphocytes from CVID patients stimulated with optimal doses of anti-CD3 or suboptimal doses of anti-CD3 and anti-CD28. Stimulated T cells from CVID patients expressed normal levels of CD28, CD40L/CD154 and CTLA-4/CD152 when compared with controls. Except for higher production of IL-4 after stimulation with anti-CD3, T cells of CVID patients produced similar amounts of cytokines compared with controls. An imbalance between costimulatory molecules expression (CD28, CD40L/CD154 and CTLA-4/CD152) and cytokine production by T cells does not explain a deficient cooperation between T and B cells in this group of CVID patients.

HLA polymorphism in a Majorcan population of Jewish descent: comparison with Majorca, Minorca, Ibiza (Balearic Islands) and other Jewish communities

'Chueta' was the name given to the Catholic descendants of Jewish victims of the last Spanish Inquisition process in Majorca Island in the western Mediterranean. We have studied the allele distribution of HLA-A, -B, -Cw, -DRB1 and -DQB1 loci of 103 random, healthy, unrelated individuals belonging to the ancient Majorcan Jewish community, known locally as Chuetas, and 589 individuals from the Balearic population selected because of their typical Balearic - Majorca, Minorca or Ibiza - lineages and according to their ancestor's place of birth. Our aim was to establish the genetic relationship between Majorcan Chuetas, and Balearic and other Jewish and Mediterranean populations. Our results have shown that, to a remarkable extent, they have retained their biological identity, with a unique pattern, in terms of gene and haplotype frequencies, separate from the other populations of Majorca. The Chuetas were found to be more related to Moroccan and Libyan Jews than other Majorcans. Characteristic Jewish haplotypes, A26-B38-DRB1*13, A24-B38-DRB1*11, A1-B52-DRB1*15/16, were found in our study. Some peculiarities were observed in the distribution of common haplotypes among the three main Balearic Islands. The Ibizan population was genetically different from the other Balearic populations, with a high frequency of some haplotypes, for example, A29-Cw*16-B44-DRB1*07-DQB1*03; A1-Cw*07-B8-DRB1*03-DQB1*02. We also found a new haplotype, A25-Cw*12-B39-DRB1*11-DQB1*03(3.5%), in Ibizans and a more limited variability in the HLA alleles that were expressed, perhaps because of genetic isolation. The genetic diversity of the populations from Majorca and Minorca were similar and more related to the mainland Spanish population.