Tesis

Uji Kesesuian IgM Anti PGL-1 terhadap Indeks Bakteri dan Klasifikasinya Pada Pasien Kusta dengan PCR Sebagai Standar Validasi = Concordance of IgM Anti-PGL-1 with Bacteriological Index and Its Classification in Leprosy Patients Using PCR as the Validation Standard.

Latar Belakang: Kusta, penyakit infeksi kronis akibat Mycobacterium leprae, masih menjadi masalah kesehatan di Indonesia. Diagnosis dan klasifikasi kusta sering mengandalkan pemeriksaan klinis dan bakteriologis, namun pemeriksaan serologis IgM anti-PGL-1 dapat menjadi alat bantu yang potensial. Tujuannya menilai efektivitas kadar IgM anti-PGL-1 sebagai penanda serologis dalam mendiagnosis dan mengklasifikasikan kusta MB dan PB serta menilai kesesuaiannya dengan IB dan PCR sebagai metode diagnostik referensi Metode: Penelitian potong lintang dilakukan pada 62 pasien kusta baru (30 paucibasiler/PB, 32 multibasiler/MB) di RS Cipto Mangunkusumo dan RS Sitanala, Februari 2024–Januari 2025. Kadar IgM anti-PGL-1 diukur menggunakan ELISA, IB ditentukan melalui slit skin smear pada cuping telinga dan lesi kulit, dan realtime PCR digunakan sebagai konfirmasi molekuler. Analisis dilakukan dengan uji T dan Chisquare, dan nilai cut-offditentukan dengan Youden index. Hasil: Kadar IgM anti-PGL-1 memiliki cut-off optimal 170,76 pg/ml (Youden Index 0,806, sensitivitas 100%, spesifisitas 80,6%), dengan 32/32 pasien MB dan 6/30 pasien PB memiliki IgM tinggi ( ≥ 170,76 pg/ml). Indeks bakteri (IB) pada pasien MB bervariasi (+1 hingga +5), sedangkan semua pasien PB memiliki IB 0. PCR positif pada 100% pasien MB dan 53,3% pasien PB. Kesesuaian IB dengan PCR menunjukkan Kappa 0,474 (p=0,001, sedang), sementara IgM anti-PGL-1 dengan PCR memiliki Kappa 0,386 (p=0,001, sedang lemah). Kesesuaian IgM anti-PGL-1 dengan IB sangat kuat (Kappa 0,838, p < 0 ,001, hampir sempurna). Kurva ROC menunjukkan kemampuan diskriminasi IB (AUC 0,984) dan IgM anti-PGL-1 (AUC 0,9098) sangat baik untuk membedakan MB dan PB. Kesimpulan: IgM anti-PGL-1 efektif digunakan untuk klasifikasi kusta MB dan PB, dengan cut-off170,76 pg/mL. Tes ini sangat relevan untuk skrining di daerah endemik, pengelolaan pasien, dan pencegahan penularan. Penelitian lanjutan dengan kelompok kontrol sehat dan validasi cut-offakan memperkuat aplikasi klinis tes ini.
Kata Kunci: Kusta, IgM anti-PGL-1, indeks bakteriologis, PCR, diagnosis, klasifikasi, ELISA.


Background: Leprosy, a chronic infectious disease caused by Mycobacterium leprae, remains a public health challenge in Indonesia. Diagnosis and classification of leprosy often rely on clinical and bacteriological examinations, but serological testing for IgM anti-PGL-1 shows potential as a diagnostic aid.The purpose of this study is to evaluate the effectiveness of IgM anti-PGL-1 levels as a serological marker in diagnosing and classifying multibacillary (MB) and paucibacillary (PB) leprosy, as well as to assess its agreement with the bacteriological index (BI) and PCR as reference diagnostic methods. Methods: A cross-sectional study was conducted on 62 newly diagnosed leprosy patients (30 paucibacillary/PB, 32 multibacillary/MB) at Cipto Mangunkusumo Hospital and Sitanala Hospital from February 2024 to January 2025. IgM anti-PGL-1 levels were measured using ELISA, BI was assessed via slit skin smear from earlobes and skin lesions, and real-time PCR was used for molecular confirmation. Data were analyzed using T-tests and Chi-square tests, with the cut-off value determined by the Youden Index. Results: The optimal IgM anti-PGL-1 cut-off was 170.76 pg/ml (Youden Index 0.806, sensitivity 100%, specificity 80.6%), with 32/32 MB and 6/30 PB patients having high IgM levels ( ≥ 170.76 pg/ml). The BI in MB patients ranged from +1 to +5, while all PB patients had a BI of 0. PCR was positive in 100% of MB patients and 53.3% of PB patients. The concordance between BI and PCR showed a Kappa coefficient of 0.474 (p=0.001, moderate), while IgM anti-PGL-1 with PCR had a Kappa of 0.386 (p=0.001, weak-moderate). The concordance between IgM anti-PGL-1 and BI was very strong (Kappa 0.838, p < 0.001, near-perfect). ROC curves demonstrated excellent discriminative ability for BI (AUC 0.984) and IgM anti-PGL-1 (AUC 0.9098) in distinguishing MB from PB. Conclusion: IgM anti-PGL-1 is effective for classifying MB and PB leprosy, with a cutoff of 170.76 pg/ml. The test is highly relevant for screening in endemic areas, patient management, and preventing transmission, although PCR confirmation is needed for PB cases with high IgM levels. Further studies incorporating a healthy control group and cut-offvalidation are recommended to enhance the clinical applicability ofthis test.
Keywords: Leprosy, IgM anti-PGL-1, bacteriological index, PCR, diagnosis, classification, ELISA