B-cell activation with CD40L or CpG measures the function of B-cell subsets and identifies specific defects in immunodeficient patients

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• 作者：Emiliano Marasco ; Chiara Farroni ; Simona Cascioli ; Valentina Marcellini ; Marco Scarsella ; Ezio Giorda ; Eva Piano Mortari ; Lucia Leonardi ; Alessia Scarselli ; Diletta Valentini ; Caterina Cancrini ; Marzia Duse ; Ola Grimsholm and Rita Carsetti
• 刊名：European Journal of Immunology
• 出版年：2017
• 出版时间：January 2017
• 年：2017
• 卷：47
• 期：1
• 页码：131-143
• 全文大小：2870K
• ISSN：1521-4141

文摘

Around 65% of primary immunodeficiencies are antibody deficiencies. Functional tests are useful tools to study B-cell functions in vitro. However, no accepted guidelines for performing and evaluating functional tests have been issued yet. Here, we report our experience on the study of B-cell functions in infancy and throughout childhood. We show that T-independent stimulation with CpG measures proliferation and differentiation potential of memory B cells. Switched memory B cells respond better than IgM memory B cells. On the other hand, CD40L, a T-dependent stimulus, does not induce plasma cell differentiation, but causes proliferation of naïve and memory B cells. During childhood, the production of plasmablasts in response to CpG increases with age mirroring the development of memory B cells. The response to CD40L does not change with age. In patients with selective IgA deficiency (SIgAD), we observed that switched memory B cells are reduced due to the absence of IgA memory B cells. In agreement, IgA plasma cells are not generated in response to CpG. Unexpectedly, B cells from SIgAD patients show a reduced proliferative response to CD40L. Our results demonstrate that functional tests are an important tool to assess the functions of the humoral immune system.