Ekspresi Imunoglobulin A pada Sel Plasma di Sekitar Sel Tumor Karsinoma Nasofaring Tidak Berkeratin, Tidak Berdiferensiasi yang Terinfeksi Virus Epstein-Barr

Background Nasopharyngeal carcinoma (NPC) is one of the most frequent malignant tumors in Indonesia, with incidence rate 6.2/100.000. The IgA-VCA serologic examination is considered as a useful marker for early detection of NPC because its high sensitivity and specificity to NPC. IgA antibody titer to Epstein-Barr Virus (EBV) increased before the tumor arise, and it lower in ≤ 30 years old patients compare to > 30 years old patients. The aim of this study is to evaluated the expression of IgA in biopsy specimen of EBV infected undifferentiated NPC among both ≤ 30 and > 30 years old patients. Methods A cross-sectional retrospective study was performed in 13 young and 20 old groups of age of undifferentiated NPC. The EBER positive undifferentiated NPC was stained with IgA by immunohistochemistry, and then analized it between the two of age groups. Results EBER positivity was found in all undifferentiated NPC. IgA was expressed in the normal surface epithelial submucous plasma cells and stromal plasma cells surounding the tumor mass in all cases of undifferentiated NPC with differented positivity. Statistical analysis with unpaired t test showed that IgA expression is significantly lower in ≤ 30 years old patients than > 30 years old patients with p value 0.025. Conclusion IgA is expressed in plasma cell cytoplasm in the stromal site of undifferentiated NPC and influenced by age.