Factors affecting serum IgA antibody to Epstein-Barr viral capsid antigens in nasopharyngeal carcinoma

Abstract

Summary.-Irrespective of the ethnic origin of the patient, nasopharyngeal carcinoma (NPC), appears to stimulate the production of IgA antibodies against VCA. These antibodies are detected at high frequency and titres in sera from NPC patients but only rarely from control subjects. A majority of relapse-free survivors tested 1-12 years after radiotherapy (RT) sustain a detectable level of IgA anti-VCA. Serum titres of IgA anti-VCA remain relatively unchanged in individual NPC patients after RT, regardless of the disease evolution. These antibodies were detected in serum from one individual 9 months before NPC and the titre rose concomitantly with its clinical onset.

Sustained elevation of Epstein–Barr virus antibody levels preceding clinical onset of nasopharyngeal carcinoma

“…It is a special feature of NPC that patients commonly sustain high levels and a broad spectrum of serum EBV antibodies (Olds et al, 1966;Henle et al, 1970;Henle and Henle, 1976;Ho et al, 1978a;Zeng et al, 1983;Cheng et al, 2002;Chan et al, 2003;Fachiroh et al, 2004). The conditions conducive to such a state seem to be attributed not only to the regular presence of the virus in the tumour cells, but also to lymphoid stroma surrounding the tumour (Ho et al, 1978b;Niedobitek et al, 1996).…”

“…It has a strong association with the human herpesvirus, Epstein -Barr virus (EBV) (Raab-Traub, 2002), with general elevation of serum EBV antibody level being an outstanding feature of the tumour (Olds et al, 1966;Henle et al, 1970;Henle and Henle, 1976;Ho et al, 1978a;Zeng et al, 1983;Cheng et al, 2002;Chan et al, 2003;Fachiroh et al, 2004). EBV antibody screening in sera of populations in high incidence areas for NPC can be useful in predicting onset of the cancer (Yi et al, 1980;Zeng et al, 1983;Chien et al, 2001;Ji et al, 2003a, b).…”

“…EBV antibody screening in sera of populations in high incidence areas for NPC can be useful in predicting onset of the cancer (Yi et al, 1980;Zeng et al, 1983;Chien et al, 2001;Ji et al, 2003a, b). This is presumed to reflect rises in antibody levels at an early stage in cancer development (Ho et al, 1978a;Cheng et al, 2002).…”

Assessing the risk of nasopharyngeal carcinoma on the basis of EBV antibody spectrum

“…Previous population studies carried out in high-incidence areas for NPC estimated the occurrence of the cancer among apparently healthy subjects having an elevated serum level of VCA IgA to be about 1% per year. 4,5,7 In practice, this serves to alert the individuals and clinicians to early symptoms of the cancer.…”

“…It was calculated as the product of the fractions of patients expected to have high (sensitivity/100) or low ([1 Ϫ sensitivity]/100) levels of each of the 3 antibodies.- 3 The expected percent of HS having a given antibody profile was derived from the observed specificity of the 3 assays (see Table II). It was calculated as the product of the fraction of HS having high (1 Ϫ specificity/100) or low (specificity/100) level of each of the 3 antibodies.- 4 Odds ratios were calculated as the ratios of expected percent of NPC to expected percent of HS having the different antibody profiles.-5 r ϭ correlation coefficient between the observed and the expected distribution of either groups of the study subjects.…”