Farhad Ali Khattak1, Noor Ul Akbar2, Maira Riaz3, Mubashir Hussain4, Khalid Rehman5, Shahid Niaz Khan6, Taj Ali Khan7. 1. Department of Microbiology, Kohat University of Science and Technology, Kohat, Pakistan; Khyber College of Dentistry, Peshawar, Pakistan. Electronic address: farhadkcd@gmail.com. 2. Department of Zoology, Kohat University of Science and Technology, Kohat, Pakistan. Electronic address: noorpak_2005@yahoo.com. 3. Department of Microbiology, Kohat University of Science and Technology, Kohat, Pakistan. Electronic address: maira.riaz21@gmail.com. 4. Department of Microbiology, Kohat University of Science and Technology, Kohat, Pakistan. Electronic address: mubashirbangash@gmail.com. 5. Institute of Public Health and Social Sciences, Khyber Medical University, Peshawar, Pakistan. Electronic address: drkhalid.iph@kmu.edu.pk. 6. Department of Zoology, Kohat University of Science and Technology, Kohat, Pakistan. Electronic address: shahid@kust.edu.pk. 7. Institute of Pathology and Diagnostic Medicine, Khyber Medical University, Peshawar, Pakistan. Electronic address: tajalikhan.ibms@kmu.edu.pk.
Abstract
BACKGROUND: The IL-12/IFN-γ axis plays a vital role in the control of intramacrophagic pathogens including Leishmania infections. OBJECTIVE: The aim of this study was to investigate genetic defects in the IL-12/IFN-γ axis in cutaneous leishmaniasis patients, using immunological and genetic evaluation. METHODS: Enzyme-linked immunosorbent assay was used to quantify IFN-γ , while flow cytometry was performed to analyze surface IL-12Rβ1/IL-12Rβ2 expression and phosphorylation of signal transducers as well as the activator of transcription 4 (pSTAT4). Sequencing was carried out for genetic analysis. RESULTS: The peripheral blood mononuclear cells from the two patients (P1 and P2) demonstrated impaired production of IFN-γ. Furthermore, abolishment of the surface expression of Il-12Rβ1 was observed in lymphocytes, with consequent impairment of STAT4 phosphorylation in the lymphocytes of P1 and P2. IL-12Rβ1 deficiency was identified, which was caused by a novel homozygous missense mutation (c.485>T/p.P162L) and a novel homozygous nonsense mutation (c.805G>T/P.E269*) in the IL-12Rβ2 gene of P1 and P2, respectively. In silico analyses predicted these novel mutations as being pathogenic, causing truncated proteins, with consequent inactivation. CONCLUSION: Our data have expanded the phenotype and mutation spectra associated with IL-12Rβ1 deficiency, and suggest that patients with CL should be screened for mutations in genes of the IL-12/IFN-γ axis.
BACKGROUND: The IL-12/IFN-γ axis plays a vital role in the control of intramacrophagic pathogens including Leishmania infections. OBJECTIVE: The aim of this study was to investigate genetic defects in the IL-12/IFN-γ axis in cutaneous leishmaniasis patients, using immunological and genetic evaluation. METHODS: Enzyme-linked immunosorbent assay was used to quantify IFN-γ , while flow cytometry was performed to analyze surface IL-12Rβ1/IL-12Rβ2 expression and phosphorylation of signal transducers as well as the activator of transcription 4 (pSTAT4). Sequencing was carried out for genetic analysis. RESULTS: The peripheral blood mononuclear cells from the two patients (P1 and P2) demonstrated impaired production of IFN-γ. Furthermore, abolishment of the surface expression of Il-12Rβ1 was observed in lymphocytes, with consequent impairment of STAT4 phosphorylation in the lymphocytes of P1 and P2. IL-12Rβ1 deficiency was identified, which was caused by a novel homozygous missense mutation (c.485>T/p.P162L) and a novel homozygous nonsense mutation (c.805G>T/P.E269*) in the IL-12Rβ2 gene of P1 and P2, respectively. In silico analyses predicted these novel mutations as being pathogenic, causing truncated proteins, with consequent inactivation. CONCLUSION: Our data have expanded the phenotype and mutation spectra associated with IL-12Rβ1 deficiency, and suggest that patients with CL should be screened for mutations in genes of the IL-12/IFN-γ axis.