Primary EBV infection and hypersensitivity to mosquito bites： a case report

Dear Editor, Hypersensitivity to mosquito bites （HMB） is primarily seen in children and adolescents in Asia and Central America. HMB may be related to the reactivation of Eps- tein-Barr virus （EBV） in infectzd natural killer （NK） cells and is directly associated with chronic active EBV infection （CAEBV） and NK/T-cell leukemia/lymphoma. The median age at diagnosis of HMB is 6.7 years, and local cutaneous reactions include erythema, bullae, ne- crosis, and ulceration. In addition, systemic symptoms, including high-grade fever, malaise, lymphadenopathy, hepatosplenomegaly, hepatic dysfunction, hematuria, and proteinuria, are often present. While the etiology of HMB remains unclear, mosquito salivary gland extract may trigger EBV reactivation in latently infected NK cells. Upon reactivation, EBV oncogenes, such as latent membrane protein 1 （LMP1）, may induce immortaliza- tion of NK cells, eventually progressing to lymphoma.

CD21-independent Infection of Epstein-Barr Virus in Human Signet Ring Gastric Carcinoma Cell Line

To study the mechanism of infection of Epstein-Barr virus (EBV) in gastric carcinoma cells, the Akata and P3HR-1 strains of EBV were used as the test strains of viruses, and the signet ring cell line HSC-39 of gastric carcinoma cells was used as the target cells of infection. The virus-infected cell clones were isolated by limited dilution method. It was found that the EBV-encoded small RNA (EBER) could be detected in the infected cells. The Akata and P3HR-1 EBV infected parental cells and most of clones expressed EBNA1, but not EBNA2. Latent membrane protein (LMP-1) and LMP-2, and the Q promoter (p), but not the Cp/Wp for EBNA gene transcription was active in the infected parental cells as well as all the clones. Uninfected HSC-39 cells did not express CD21, however, Akata but not P3HR-1 EBV-infected clones expressed low level of CD21 mRNA. These results demonstrate that HSC-39 cells are susceptible to both EBV strains and EBV infects HSC-39 cells through the CD21-independent pathway. This study defines a signet ring type of gastric carcinoma cells line as a unique target cells for the study of EBV infection mechanism.

Chronic Active Epstein–Barr Virus Infection

Chronic active Epstein-Barr virus(CAEBV)infection is a systemic Epstein–Barr virus(EBV)positive lymphoprolifetative disease characterized by fever,lymphadenopathy,splenomegaly,unusual pattern of antiEBV antibodies,and/or increased EBV genomes in affected tissues.Most cases are from Asia.So far,there is hardly any adult case reported from mainland of China.We herein presented a 33-year-old man with fever,facial erythema and rash,lymphadenopathy,lower limbs weakness,splenomegaly and liver lesion.EBV VCA,EA and EBNA were all positive.EBV DNA could be found in serum and PBMC.In situ hybridization of EBV encoded RNA in skin and liver biopsy was positive.Viral load in serum decreased under interferon alpha therapy.To our knowledge,it’s the first adult case reported from mainland of China.