Epstein-Barr Virus (EBV), IgA, Serum
The test is indicated for patients with malignant lesions of type 2 and 3 in whom nasopharyngeal carcinoma is suspected; eg, patients with metastases to the cervical lymph nodes from an unknown primary source.
Clinical Information Discusses physiology, pathophysiology, and general clinical aspects, as they relate to a laboratory test
Infection with Epstein-Barr virus (EBV) usually occurs early in life. For several weeks to months after acute onset of the infection, it is spread by upper respiratory secretions that contain the virus.
Among the clinical disorders due to EBV infections, infectious mononucleosis is most common. Other disorders due to EBV infection have been recognized for several years, including African-type Burkitt lymphoma and nasopharyngeal carcinoma (NPC). The World Health Organization (WHO) classifies NPC as type 1 (keratinizing squamous cell carcinoma), type 2 (nonkeratinizing squamous cell carcinoma), and type 3 (undifferentiated carcinoma).
EBV infection also may cause lymphoproliferative syndromes, especially in patients who have undergone renal or bone marrow transplantation and in those who have AIDS.
Reference Values Describes reference intervals and additional information for interpretation of test results. May include intervals based on age and sex when appropriate. Intervals are Mayo-derived, unless otherwise designated. If an interpretive report is provided, the reference value field will state this.
Presence of IgA class antibody to the viral capsid antigen (VCA) of Epstein-Barr virus (EBV) indicates active replication of EBV.
High levels of IgA class antibody to the VCA supports the clinical diagnosis of nasopharyngeal carcinoma (NPC). These antibodies are present in 84% of patients with type 2 NPC.
IgA directed against VCA is positive for type 1 carcinoma in only 16% of cases.
The specificity of the test is such that 82% to 91% of healthy blood donors and patients who do not have NPC have negative responses.
Cautions Discusses conditions that may cause diagnostic confusion, including improper specimen collection and handling, inappropriate test selection, and interfering substances
It should be noted that there are some patients with nasopharyngeal carcinoma whose serum will contain antibodies to the early antigen (EBVE / Epstein-Barr Virus [EBV], IgG Antibody to Early Antigen, Serum) of the virus but not antibodies to the viral capsid antigen and vice versa.
Clinical Reference Provides recommendations for further in-depth reading of a clinical nature
1. Liu MT, Cy Y: Prognostic value of anti-Epstein-Barr Virus antibodies in nasopharyngeal carcinoma (NPC). Radiat Med 1998;16:113-117
2. Puthavathana P, Kositanont U, Chongkolwantana C, et al: Prevalence of IgA specific antibodies to Epstein-Barr Virus capsid and early antigens in nasopharyngeal carcinoma. Asian Pac J Allergy Immonol 1993;11:39-43