Varicella-zoster virus (VZV) causes chickenpox and shingles. While varicella is likely spread as cell-free virus to susceptible hosts, the virus is transmitted by cell-to-cell spread in the body and in vitro. Since VZV glycoprotein E (gE) is essential for virus infection, we postulated that gE binds to a cellular receptor. We found that insulin-degrading enzyme (IDE) interacts with gE through its extracellular domain. Downregulation of IDE by siRNA, or blocking of IDE with antibody, with soluble IDE protein extracted from liver, or with bacitracin inhibited VZV infection. Cell-to-cell spread of virus was also impaired by blocking IDE. Transfection of cell lines impaired for VZV infection with a plasmid expressing human IDE resulted in increased entry and enhanced infection with cell-free and cell-associated virus. These studies indicate that IDE is a cellular receptor for both cell-free and cell-associated VZV.

Vaccinations are effective in preventing infections; however, it is unknown if patients with chronic lymphocytic leukemia (CLL) who are treatment naïve (TN) or receiving Bruton tyrosine kinase inhibitors (BTKis) respond to novel adjuvanted vaccines. Understanding the effect of BTKis on humoral immunity is timely because BTKis are widely used and vaccination against COVID-19 is urgently needed. In two open-label, single-arm clinical trials, we measured the effect of BTKis on de novo immune response against recombinant hepatitis B vaccine (HepB-CpG) and recall response against recombinant zoster vaccine (RZV) in CLL patients who were TN or on BTKi. The primary endpoint was serologic response to HepB-CpG (anti-HBs ≥10 mIU/mL) and RZV (≥4-fold increase in anti-glycoprotein E). The response rate to HepB-CpG was lower in patients on BTKi (3.8% [95% CI, 0.7%-18.9%]) than TN patients (28.1% [95% CI, 15.6%-45.4%], P=.017). In contrast, the response rate to RZV did not differ significantly between the BTKi (41.5% [95% CI, 27.8%-56.6%]) and TN cohorts (59.1% [95% CI, 38.7%-76.7%], P=.2). BTKis were associated with a decreased de novo immune response following HepB-CpG, whereas recall immune response following RZV was not significantly affected by BTKi therapy. Trials were registered at www.clinicaltrials.gov as NCT03685708 (Hep-CpG) and NCT03702231 (RZV).

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IntroductionEpstein-Barr virus (EBV) is a member of the human herpesvirus family that infects over 95% of the United States population. 1 Most infections occur in childhood and are asymptomatic; infection of adolescents and young adults with EBV often results in infectious mononucleosis. EBV is associated with a spectrum of lymphoproliferative diseases in patients with congenital or acquired immunodeficiency.Chronic active EBV infection (CAEBV) is a rare and often fatal disorder that occurs in previously healthy persons and seemingly immunocompetent persons. 2 The disease has been defined by the presence of 3 features. 3,4 First, patients have a severe progressive illness that began as a primary EBV infection, or is associated with abnormal EBV-specific antibody titers that include markedly elevated antibodies to viral capsid antigen (VCA) and early antigens (EAs). Second, histology shows evidence of major organ involvement such as lymphadenitis, hemophagocytosis, meningoencephalitis, or persistent hepatitis. Third, elevated EBV DNA, RNA, or proteins are demonstrable by in situ hybridization or immunohistochemical staining of affected tissues. Recent studies showed that patients with CAEBV can also have markedly elevated levels of EBV DNA in the peripheral blood and this criterion has been used diagnostically in some cases. 5 Patients with CAEBV often develop a progressive cellular and humoral immunodeficiency with pancytopenia and hypogammaglobulinemia that renders them susceptible to opportunistic infections or B-or T-cell lymphoproliferative disease. 3 Therapy for CAEBV is unsatisfactory and, at best, progression of disease is temporarily delayed.The etiology of CAEBV is unknown. Two studies suggested that persons with CAEBV were infected with unusual lytic strains of virus. 6,7 However, the finding of the same lytic strain of EBV in the unaffected father of one of the patients, and in healthy controls, 8 suggests that other factors, including inherited abnormalities in the response to EBV, contribute to the pathogenesis of the disease. Four observations favor a genetic cause for CAEBV. First, CAEBV is rare in the United States, but relatively common in Japan, Korea, and China. Most patients reported to have fulminant EBV-positive T-cell lymphoproliferative disease following acute and/or chronic EBV infection have been Asian in origin. 9 Second, specific mutations in the signaling lymphocyte activation molecule (SLAM) associated protein (SAP) gene have been identified in boys with a disease that shares many of the features of CAEBV, the X-linked lymphoproliferative disease (XLPD). [10][11][12] Third, 2 studies showed that cytotoxic T lymphocyte (CTL) or natural killer (NK) cell activity was reduced in patients with CAEBV and in their parents. 13,14 Fourth, gene mutations and polymorphisms have been associated with severe infections with herpesviruses including EBV. [15][16][17] Taken together, these findings suggest that a genetic abnormality could underlie some cases of CAEBV.Here we describe a patient with ...