Banca de DEFESA: LUCIANA PEREIRA FREIRE MARTINS

Uma banca de DEFESA de DOUTORADO foi cadastrada pelo programa.
STUDENT : LUCIANA PEREIRA FREIRE MARTINS
DATE: 04/08/2026
TIME: 08:30
LOCAL: Plataforma TEAMS
TITLE:

TRANSIENT POSITIVITY OF CIRCULATING LEISHMANIA kDNA IN THE PERIPHERAL BLOOD OF IMMUNOSUPPRESSED PATIENTS EXPOSED TO LEISHMANIASIS AND ITS RELATIONSHIP WITH GENE EXPRESSION OF THE JAK-STAT PATHWAY

KEY WORDS:

Leishmaniasis, Immunology, Molecular Biology, Diagnosis.

PAGES: 80
BIG AREA: Ciências Biológicas
AREA: Imunologia
SUMMARY:

Introduction: Leishmaniasis is a neglected tropical disease (NTD) and is endemic in 99 countries. The epidemiology of NTDs, in general, is related to environmental conditions, such as limited access to adequate sanitation, clean water, and healthcare. Furthermore, immunosuppression can lead to a higher risk of infection and illness caused by Leishmania. There are reports in the literature of leishmaniasis cases in patients with drug-induced immunosuppression. Objectives: This study aims to screen for the occurrence of leishmaniasis in immunosuppressed patients treated at the University Hospital of Brasília (HUB), considering the profile of pro-inflammatory and anti-inflammatory responses, as well as the JAK-STAT (Janus kinase-signal transducer and activator of transcription) signalling pathway. Methodology: Immunosuppressed patients treated at the HUB were consecutively included. These patients underwent a clinical dermatological examination. The screening for Leishmania in peripheral blood was performed using real-time polymerase chain reaction (PCR) targeting kinetoplast DNA (kDNA) on two occasions during the patients' 6-month clinical follow-up. Gene expression analyses of various cytokines, including the JAK-STAT pathway of peripheral blood mononuclear cells (PBMCs), were performed. Cases of patients with circulating Leishmania kDNA in their blood were compared with those who did not present this finding (control group). Results: A total of 488 patients were included in the study, with a mean age of 49.28 years. Out of the 488 included patients, 295 were using systemic immunosuppressive therapies. Throughout the follow-up period, no cases of active leishmaniasis—either visceral or cutaneous—were diagnosed. However, molecular analysis of the patients revealed the presence of Leishmania kDNA in the peripheral blood of 45 patients, detected at least at one of the evaluated time points (either at recruitment or after six months of follow-up). It was observed that 8 out of 30 patients (26.67%) using systemic corticosteroids alone tested positive for circulating Leishmania kDNA in the blood, whereas among patients using other grouped treatments, only 19 out of 265 (7.17%) tested positive ($p = 0.001$). In the adjusted analysis, positivity for circulating Leishmania kDNA at recruitment proved to be an independent risk factor for positivity after six months (Relative Risk = 26.00, 95% Confidence Interval = 8.77–77.11, $p < 0.001$). The analysis of the relative quantification of gene expression for the evaluated immunological mediators showed downregulation of tyrosine kinase 2 (TYK2) and interleukin (IL) 12A in patients with detectable circulating Leishmania kDNA in peripheral blood. Conclusions: It can be concluded that Leishmania kDNA in peripheral blood may be a persistent finding in immunosuppressed patients living in an endemic area. The use of systemic corticosteroids appears to have a greater influence on this positivity. More comprehensive studies with long follow-up periods are necessary to elucidate the role of these findings in the development of clinically active leishmaniasis

COMMITTEE MEMBERS:
Externa à Instituição - ADA AMÁLIA AYALA URDAPILLETA - SESDF
Presidente - 2676451 - CIRO MARTINS GOMES
Externo à Instituição - GILBERTO SANTOS MORAIS JUNIOR - UnB
Interna - 3088161 - JULIANA LOTT DE CARVALHO
Externa à Instituição - MARIANA MAGALHÃES NÓBREGA - IFG