immunoglobulin class switch recombination deficiencies (ig csr deficiencies) or hyper igm syndromes (higm) are a group of primary immunodeficiency diseases, characterized by defective cd40 signaling of b cells resulting into a csr and a somatic hypermutation. the affected patients are characterized with reduced serum levels of igg and iga, and normal or elevated level of igm, which lead to incr...

background: defects in b cell class switch recombination (csr) are a heterogeneous and yet very uncommon group of disorders which all have a genetic basis uniformly leading to hyper igm (higm) syndrome. due to the rare frequency of these conditions, a very small number of case series have been conducted on the affected patients. objective: to shed some light on the morbidity and mortality regar...

background: crimean-congo hemorrhagic fever virus (cchfv) belongs to genus nairovirus and family bunyaviridae. the main aim of this study was to investigate the extent of recombination in s-segment genome of cchfv in iran. methods: samples were isolated from iranian patients and those available in genbank, and analyzed by phyloge­netic and bootscan methods. results: through comparison of the ph...

Both, in humans and in mice, a major fraction of immunoglobulin E (IgE)-expressing B lymphocytes develops by sequential Ig class switching from IgM via IgG to IgE. This sequential class switch might have functional implications for the frequency and repertoire of IgE+ cells. Here we show that in mutant mice, in which sequential switching to IgE via IgG1 is blocked, the frequency of cells switch...