Imunitas Bawaan pada Kusta: Hubungan Ekspresi Kaspase-1 dengan Interleukin-18 pada Lesi Kulit Pasien Kusta

Abstract

Respons imun terhadap Mycobacterium leprae (M. leprae) terdiri atas respons imun bawaan dan didapat. Salah satu enzim yang berperan pada imunitas bawaan adalah kaspase-1 dengan fungsi memecah sitokin proinflamasi prointerleukin (IL)-18 menjadi IL-18 aktif. IL-18 bersama IL-12 secara sinergis akan merangsang produksi interferon (IFN-γ) sehingga timbul respons imun seluler yang bersifat protektif. Tujuan penelitian ini adalah menganalisis korelasi positif ekspresi kaspase-1 dengan IL-18 pada lesi kulit pasien kusta. Penelitian dilaksanakan selama bulan Oktober–Desember 2014 di Poliklinik Morbus Hansen Departemen Ilmu Kesehatan Kulit dan Kelamin serta Laboratorium Imunohistokimia Departemen Patologi Anatomi Fakultas Kedokteran Universitas Padjadjaran/Rumah Sakit Dr. Hasan Sadikin Bandung. Penelitian ini merupakan penelitian klinis analitik observasional dengan rancangan potong lintang. Subjek penelitian berjumlah 19 pasien kusta yang didapatkan melalui consecutive sampling. Terhadap subjek penelitian dilakukan anamnesis, pemeriksaan fisis, pemeriksaan bakteriologis, dan biopsi plong. Pada jaringan hasil biopsi lesi kulit dilakukan pemeriksaan imunohistokimia ekspresi kaspase-1 dan IL-18 yang dinilai dengan histoscore, kemudian dilakukan analisis korelasi menggunakan uji Rank-Spearman. Pada hasil penelitian ini didapatkan nilai ekspresi histoscore kaspase-1 pada lesi kulit pasien kusta berturut-turut tipe tuberkuloid (TT)=12,00; borderline tuberculoid (BT)=8,33; mid-borderline (BB)=8,00; borderline lepromatous (BL)=4,00; dan lepromatous (LL)=10,67. Nilai histoscore ekspresi IL-18 pada lesi kulit pasien kusta berturut-turut pada tipe TT=9,33; BT=6,50; BB=4,60; BL=4,00; dan LL=9,33. Berdasarkan hasil analisis statistik uji Rank-Spearman pada derajat kepercayaan 95% didapatkan korelasi positif yang bermakna antara ekspresi histoscore kaspase-1 dan IL-18 (rs=0,618; p=0,005). Simpulan penelitian ini adalah terdapat korelasi positif antara ekspresi kaspase-1 dan IL-18 pada lesi kulit pasien kusta. Semakin tinggi ekspresi kaspase-1 pada lesi kulit pasien kusta maka semakin tinggi ekspresi IL-18. [MKB. 2016;48(3):181–6]

Kata kunci: Imunitas bawaan, interleukin-18, kaspase-1, kusta

Innate Immunity in Leprosy: Correlation between Caspase-1 and Interleukin-18 Expression in Leprosy Patient’s Skin Lesion

 Immune response against M. leprae contains innate and adaptive immunity. Caspase-1 is one of the enzymes which have a role in innate immunity to activate pro-IL-18 into its active form. IL-18 and IL-12 sinergically enhance the production of IFN-γ which triggers the protective cellular immunity. The aim of this study was to analyze the positive correlation between the expression of caspase-1 and IL-18 in leprosy patients’ skin lesions. The study was conducted from October tol December 2014 at the Dermatology and Venereology, and Immunohistochemistry Laboratory, Pathology Anatomy Department, Universitas Padjadjaran/Dr. Hasan Sadikin General Hospital Bandung. This was a clinical observational analytical study with cross-sectional design. Subjects were 19 leprosy patients recruited through consecutive sampling. History taking, physical examination, bacteriological examination, and punch biopsy were performed on all subjects. Caspase-1 and IL-18 expressions were examined and measured with histoscore. Correlation analysis was performed using Rank-Spearman test. The histoscore for the expression of caspase-1 in leprosy patients’ skin lesions was as follows: TT type=12.00; BT=8.33; BB=8,00; BL=10.00; and LL=10.67. The histoscore for the IL-18 expression in leprosy patients’ skin lesions were TT type=9.33; BT=4.60; BL=4.00; and LL=9.33. Rank-Spearman analysis with desired confidence level of 95% showed a statistically significant positive correlation between the histoscore of caspase-1 expression and IL-18 expression.(rs=0.618, p=0.005). In conclusion, this study demonstrates a positive corelation between caspase-1 expression and IL-18 expression in leprosy skin lesions. An increase of caspase-1 expression indicates an increase of IL-18 expression. [MKB. 2016;48(3):181–6]

Key words: Caspase-1, interleukin-18, innate immunity, leprosy