As the common clinical features of XLP are FIM, EBV-associated HLH and lymphoproliferative disorder [2, 3], we completed SH2D1A and XIAP gene sequencing in the patients with one or more of these symptoms in this study. Most XLP patients appear healthy prior to contracting EBV [16]. However, following infection, patients often develop T and B cell lymphoproliferation and secondary HLH [16, 17]. Using gene sequencing, we diagnosed five patients with XLP of the 21 male patients in our study with FIM, EBV-associated HLH or persistent EBV
viremia. The overall clinical phenotypes of the affected persons matched those previously reported. All of the five patients had symptoms of HLH and four tested positive for EBV-DNA. This finding indicated that EBV infection triggers HLH in patients with SH2D1A or XIAP deficiency. Although Patient 2 was EBV-DNA negative, we still consider HLH as triggered
Cell Cycle inhibitor by EBV infection based on the elevated atypical lymphocyte counts. Previous study reported that about 13 XLP patients showed hypogammaglobulinemia [18]. In our study, 1 patient with SH2D1A deficiency had lower IgG, IgA and IgM levels, especially IgG. The results indicate that the patient had hypogammaglobulinemia. All four patients evaluated for immunological function showed a low CD4/CD8 ratio, which may be associated with EBV infection. Talazoparib order In patients with XLP, disease onset is usually triclocarban at 2–5 years of age and is often triggered by EBV infection [16, 19]. Among the five patients in the study, the youngest one was only 1 month old at time of onset. It is different with the western world, maybe due to early encountering of the EBV infection. Although there is no precise epidemiological data of EBV infection, the age of onset is thought to vary widely, with developed countries having
higher ages at primary infection, most likely due to better hygienic conditions and other socioeconomic and demographic factors including household size and population density [20]. The result indicates that patients with SH2D1A or XIAP deficiency can show XLP associated symptoms at a very young age. Prior reports indicate that the prognosis for XLP is poor, with 70% of patients dying before the age of 10 and mortality nearing 96% for those with a history of EBV infection [2, 4, 5]. In our study, three patients had rapid disease progression and died. Only one patient received HSCT and is well. The prognosis observed in our study is therefore similar to previous studies. In summary, we report the clinical and genetic features of five Chinese patients with SH2D1A/XIAP deficiency in this study. For patients with severe EBV-associated HLH, our results indicate the need to consider the possibility of XLP. This work was supported by the National Natural Science Foundation of China (81172877, 81000260) and Shanghai Rising-Star Program (11QA1400700). All authors declare no conflict of interest.