PERBANDINGAN RESPON IgA TERHADAP PEPTIDA EARLY ANTIGEN (EA) VIRUS EPSTEIN-BARR DENGAN PROTEIN-KOMPLEKS EA SEBAGAI KANDIDAT PENANDA DETEKSI KARSINOMA NASOFARING

AKMAL AKBAR, D.K. Paramita; J. Fachiroh

2014 | Skripsi | PENDIDIKAN DOKTER

Latar belakang: Di Indonesia, NPC merupakan kanker kepala leher dengan insidensi tertinggi ke-dua pada lakilaki setelah kanker paru dengan mayoritas (>80%) memiliki tipe histopatologi WHO III, yang berkorelasi hamper 100% dengan infeksi EBV. Uji serologi ELISA berbasis EBV banyak dikembangkan untuk serodiagnosis NPC. Antigen berbentuk peptida sintetik mulai dikembangkan karena lebih stabil dan dapat diproduksi. Tujuan: Mengkaji kemaknaan diagnosis IgA-EA-1580 dan IgA-EA-1582 dengan membandingkan sensitivitas, spesifisitas, PPV (positive predictive value), dan NPV (negative predictive value) dengan IgA-EA ekstrak. Metode: Plasma yang telah dikoleksi dan diisolasi dari pasien NPC (n=100) dan donor sehat (n=100) diukur respon IgA-nya terhadap EA-1580 dan EA-1582 dengan metode ELISA. Uji Mann-Whitney dilakukan untuk menguji signifikasi perbedaan respon IgA pada masing-masing kelompok. CoV (cut-off value) ditentukan dengan analisis ROC, kemudian dihitung sensitivitas, spesifisitas, PPV, dan NPV dari respon IgA terhadap masing-masing peptida. Hasil: Uji Mann-Whitney menunjukkan respon IgA terhadap kedua peptida pada pasien NPC dan donor sehat memiliki perbedaan yang signifikan (nilai p IgA-EA- 1580=0,008; nilai p IgA-EA-1582=0,026). IgA-EA-1580 memiliki sensitivitas, spesifisitas, PPV, dan NPV masingmasing sebesar 44%, 98%, 95,6%, dan 36,4%. Sedangkan IgAEA- 1582 sebesar 43%, 97%, 93,5%, dan 63%. Sensitivitas, spesifisitas, PPV, dan NPV IgA-EA ekstrak yang didapat dari penelitian Paramita et al. (2007) sebesar 85,7%, 94%, 79,4%, dan 94,9%. Kesimpulan: IgA-EA-1580 dan IgA-EA-1582 tidak sebaik IgA-EA ekstrak untuk digunakan sebagai metode serodiagnosis NPC karena sensitivitasnya relatif rendah.

Background: In Indonesia, NPC is the second most common malignancy in male after lung cancer. Most NPC in Indonesia is presented as WHO III, which showed almost 100% correlations with EBV infection. EBV based ELISA is commonly used for NPC serodiagnosis. Synthetic peptide has been proposed to be used as antigen due to its stability and reproducibility. Objectives: To assess diagnostic values of IgA-EA-1580 and IgA-EA-1582 synthetic peptides with comparing their sensitivity, specificity, PPV (positive predictive value), and NPV (negative predictive value) to IgA-EA extract. Methods: A hundred (n=100) plasma samples from NPC cases, and 100 plasma samples from healthy controls were collected, and had their IgA response to EA peptides, EA- 1580 and EA-1582 measured by indirect ELISA. Mann-Whitney test used to test the difference between cases and controls in both peptides. ROC analysis was done to determine the CoV (cut-off value) in order to determine sensitivity, specificity, PPV, and NPV of each peptide. Results: Mann-Whitney test showed IgA response between both groups have a significant difference (IgA-EA-1580 p value=0,008; IgA-EA-1582 p value=0,026). Based on cut-off value of 0,260, IgA-EA-1580 has sensitivity, specificity, PPV, and NPV values of 44%, 98%, 95,6%, and 36,4% respectively; while using cut-off value of 0,239, IgA-EA- 1582 has values of 43%, 97%, 93,5%, and 63% respectively. Overall results showed lower sensitivity compared to IgAEA extract of previous study (Paramita et al., 2007), with sensitivity, specificity, PPV, and NPV values of 85,7%, 94%, 79,4%, and 94,95 respectively. Conclusion: IgA-EA-1580 and IgA-EA-1582 had incomparative NPC serodiagnostic capacity compared to IgA-EA extract due to their low sensitivity.

Kata Kunci : Epstein-Barr virus, Nasopharyngeal Carcinoma, ELISA, Synthetic Peptide, Diagnostic Test