The change in Ig regulation from children to adults disconnects the correlation with the 3'RR hs1.2 polymorphism

Eliseo Serone, Cristina Daleno, Nicola Principi, Laura Porretti, Valentina Iacoacci, Cesare Gargioli, Andrea Magrini, Renato Massoud, Pietro D'Addabbo, Marco Cattalini, Vincenzo Giambra, Alessandro Plebani, Susanna Esposito, Domenico Frezza

Research output: Contribution to journalArticle

Abstract

Background: In the immune system, the serum levels of immunoglobulin (Ig) increase gradually during ageing. Through B cell development, the Ig heavy chain expression is modulated by a regulatory region at the 3' of the constant alpha gene (3'RR), in single copy in rodents and, due to a large duplication, in two copies in apes. The human 3'RR1 and 3'RR2 are both characterized by three enhancers, the central of which, namely hs1.2, is highly polymorphic. Human hs1.2 has four different variants with unique binding sites for transcription factors (e.g. NF-kB and SP1) and shows variable allelic frequencies in populations with immune disorders. In previous works, we have reported that in several autoimmune diseases the *2 allele of hs1.2 is genetically associated to high level of IgM in peripheral blood. In subjects with altered levels of circulating Ig, an increased level was associated to *2 allele of hs1.2 and low levels corresponded to high frequency of *1 allele. During ageing there is a physiological increase of Ig concentrations in the serum. Therefore, for this study, we hypothesized that the hs1.2 variants may impact differently the levels of secreted Ig during the growth. Results: We have correlated the allelic frequencies of hs1.2 with IgM, IgG and IgA serum concentrations in two cohorts of healthy people of different age and after three years follow-up in children homozygous for the allele. Here we show that when the expression levels of Ig in children are low and medium, the frequencies of *1 and *2 alleles are the same. Instead, when the Ig expression levels are high, there is a significantly higher frequency of the allele *2. The follow-up of children homozygous for *1 and *2 alleles showed that the increase or decrease of circulating Ig was not dependent on the number of circulating mature B cells. Conclusions: These data support the idea that under physiologic condition there is a switch of regulative pathways involved in the maturation of Ig during ageing. This mechanism is evidenced by hs1.2 variants that in children but not in adults participate to Ig production, coordinating the three class levels.

Original languageEnglish
Article number45
JournalBMC Immunology
Volume15
Issue number1
DOIs
Publication statusPublished - Nov 13 2014

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Keywords

  • Aging
  • B cell markers
  • Enhancer hs1.2
  • Genotyping
  • Immune system regulation
  • Immunoglobulin heavy chain
  • NF-κB
  • SP1
  • Transcription factor consensus

ASJC Scopus subject areas

  • Immunology

Cite this

Serone, E., Daleno, C., Principi, N., Porretti, L., Iacoacci, V., Gargioli, C., Magrini, A., Massoud, R., D'Addabbo, P., Cattalini, M., Giambra, V., Plebani, A., Esposito, S., & Frezza, D. (2014). The change in Ig regulation from children to adults disconnects the correlation with the 3'RR hs1.2 polymorphism. BMC Immunology, 15(1), [45]. https://doi.org/10.1186/s12865-014-0045-0