Cytogenetic and epidemiological profile of chronic myeloid leukemia in Morocco

Chronic myeloid leukemia (CML) is a neoplastic disease of genetic origin resulting from clonal proliferation of hematopoietic stem cells (HSCs). The reciprocal translocation t(9;22)(q34;q11) is the main chromosomal abnormality involved in this pathology, usually detected by conventional cytogenetics. This article aims to investigate the epidemiological, cytogenetic, therapeutic, and clinical characteristics of Moroccan patients with CML. This research represents the first large-scale study of CML patients in Morocco and was carried out at Institut Pasteur of Morocco. Bone marrow samples were processed for cytogenetic analysis, and karyotypes were described according to an international system of human cytogenetic nomenclature (ISCN 2016). Patients were studied according to their epidemiological characteristics, clinical information and cytogenetic results. For statistical calculations, R version 4.3.1 was used to analyze the data and calculate the statistical parameters. RStudio and Power BI were used for data visualization. The National Cancer Institute (NCI) Surveillance, Epidemiology, and End Results (SEER) method of incidence estimation was used to calculate our incidence. We received 826 patients (from 1992 to 2023) who were referred for suspected CML or who were undergoing treatment. Only 650 patients with confirmed CML were included in the study, all of whom underwent their first cytogenetic test. The median age of our patients was 45 years and the sex ratio was 1.03. At the time of diagnosis, 147 (30%) of the patients had clinical manifestations. Most patients were diagnosed in the chronic phase (94.5%). Nineteen complex variant translocations of the Philadelphia (Ph) chromosome were detected. At the time of diagnosis, 55 (11.5%) patients had ACAs, of which 30 (54.5%) were high-risk ACAs. Based on data from 174 patients treated with imatinib, the median time to complete cytogenetic response (CCyR) was 11 months, and at the last cytogenetic follow-up, 81 patients (46.6%) achieved CCyR, while 64 patients (36.8%) showed no response to treatment. Regarding adherence to European LeukemiaNet (ELN) guidelines, 58 patients (33%) were followed according to these guidelines, with optimal treatment in 8.6%, suboptimal treatment in 7% and treatment failure in 18%. The estimated incidence of chronic myeloid leukemia calculated is 0.6 cases per 100,000 in the Casablanca region. This study provides a detailed overview of CML in Morocco, highlighting important clinical, cytogenetic and therapeutic aspects despite some limitations. It also highlights the need to deepen our understanding of this complex disease for disease management in our specific context.

Chronic myeloid leukemia: cytogenetics and molecular biology’s part in the comprehension and management of the pathology and treatment evolution

Background

Chronic myelogenous leukemia (CML) is a type of blood cancer that affects hematopoietic stem cells and is often characterized by the presence of the Philadelphia chromosome. The Philadelphia chromosome encodes for a protein with high tyrosine kinase activity which acts as a tumorigenic factor.

Main body

This review article reports an update on the pathophysiology of CML and highlights the role of cytogenetic and molecular biology in screening, diagnosis, therapeutic monitoring as well as evaluating patients’ response to treatment. Additionally, these genetic tests allow identifying additional chromosomal abnormalities (ACA) and BCR-ABL tyrosine kinase domain mutations in intolerant or resistant patients. Thus, therapeutic advances have enabled this pathology to become manageable and almost curable in its clinical course. The scientific literature search used in the synthesis of this paper was carried out in the PubMed database, and the figures were generated using online software named BioRender.

Conclusion

The role of cytogenetic and molecular biology is crucial for the diagnosis and medical monitoring of patients. In-depth knowledge of molecular mechanisms of the BCR-ABL kinase facilitated the development of new targeted therapies that have improved the vital prognosis in patients. However, the emergence of ACA and new mutations resistant to tyrosine kinase inhibitors constitutes a real challenge in the quest for adequate therapy.

Epidemiological features of a recent zoonotic cutaneous leishmaniasis outbreak in Zagora province, southern Morocco

BACKGROUND

Leishmania major is an endemic vector-borne disease in Morocco that causes zoonotic cutaneous leishmaniasis (ZCL), especially in arid pre-Saharan regions where its unique vector and reservoir are Phlebotomus papatasi and Meriones shawi, respectively, and may cause epidemics. In late 2017, the Zagora province, an endemic focus for ZCL in southern Morocco, had CL outbreak. The main objective of our investigation was to analyze the epidemiological features of this latest ZCL outbreak.

METHODOLOGY/PRINCIPAL FINDINGS

We analyzed epidemiological features of this latest ZCL outbreak. The Regional Delegation of Health, Zagora, recorded 4,402 CL patients between October 2017 and end of March 2018. Our findings showed that 24 municipalities were affected and majority (55.1%) of infected cases belonged to the Tinzouline rural municipality. Majority of patients were females (57.2%). While all age group patients were affected, those aged <10 years were the most affected (42.1%). During this outbreak over 5 days in December 2017, we conducted a survey in Tinzouline and recruited and sampled 114 CL patients to confirm CL diagnosis by parasitological (direct examination and culture) and molecular (ITS1-PCR) methods and identify the etiological agent of infection using ITS1-PCR-RFLP and sequencing. We completed a detailed questionnaire including clinical and epidemiological data for each patient and found 72.8% of patients presenting multiple lesions (≥2), with an average number of lesions of 5.16 ± 0.5. Lesions were more prevalent in the upper limbs, with the most common type being the ulcerocrusted lesion (60.5%). We detected no associations between lesion type and patients' sex or age.

CONCLUSIONS/SIGNIFICANCE

Among 114 clinically diagnosed CL patients, we confirmed 90.35% and identified L. major as the species responsible for this outbreak. Self-medication using various products caused superinfection and inflammation of lesions and complicated the diagnosis and treatment. Thus, ZCL remains a major public health problem in the Zagora province, and commitment of all stakeholders is urgently required to implement a sustainable regional control program.

Genetic diversity of Leishmania tropica in Morocco: does the dominance of one haplotype signify its fitness in both predominantly anthropophilic Phlebotomus sergenti and human beings?

In Morocco, cutaneous leishmaniasis (CL) caused by Leishmania tropica is endemic to locations where the predominantly anthropophilic blood-feeding Phlebotomus sergenti and humans co-perpetuate. The objective of this study was to explore whether the range of epidemiological features of CLcould be linked to the range of L. tropica genetic heterogeneity and to further explore the relationships between the genetic diversity of L. tropica in both P. sergenti and humans. L. tropica DNAwas extracted from dermal scarping smears of 125 CLpatients. Genetic polymorphisms were analyzed by sequencing the internal transcribed spacer (ITS) 1 and 5.8S rDNAgene. Nucleotide diversity (π), haplotype diversity (Hd) and Tajima's D test for neutrality, as well as overall and pairwise FSTvalues, were calculated using Arlequin ver 3.5 software. Out of the 125 amplified DNAsequences, 93 were completely sequenced and 13 L. tropica haplotypes were identified, which confirmed the significant genetic heterogeneity of L. tropica in Morocco. The most common haplotype included 74 out of 93 sequences; this haplotype is not only widely represented but was also detected in P. sergenti, which is known to be the most abundant species in the studied foci. Considering the negative value calculated using Tajima's D index, we briefly discussed the hypothesis that the L. tropica common haplotype propagation could be a sign of its fitness in P. sergenti and human hosts. Furthermore, analysis of molecular variance (AMOVA) shows significant correlations between intraspecific variants of L. tropica and patients' geographic origins. The long-term goals of the present pilot study are to further explore the relationships between the genetic diversity of L. tropica in human and P. sergenti populations.

First Molecular Identification and Phylogeny of Moroccan Anopheles sergentii (Diptera: Culicidae) Based on Second Internal Transcribed Spencer (ITS2) and Cytochrome c Oxidase I (COI) Sequences

Anopheles sergentii known as the "oasis vector" or the "desert malaria vector" is considered the main vector of malaria in the southern parts of Morocco. Its presence in Morocco is confirmed for the first time through sequencing of mitochondrial DNA (mDNA) cytochrome c oxidase subunit I (COI) barcodes and nuclear ribosomal DNA (rDNA) second internal transcribed spacer (ITS2) sequences and direct comparison with specimens of A. sergentii of other countries. The DNA barcodes (n = 39) obtained from A. sergentii collected in 2015 and 2016 showed more diversity with 10 haplotypes, compared with 3 haplotypes obtained from ITS2 sequences (n = 59). Moreover, the comparison using the ITS2 sequences showed closer evolutionary relationship between the Moroccan and Egyptian strains than the Iranian strain. Nevertheless, genetic differences due to geographical segregation were also observed. This study provides the first report on the sequence of rDNA-ITS2 and mtDNA COI, which could be used to better understand the biodiversity of A. sergentii.

Molecular identification of Leishmania infection in the most relevant sand fly species and in patient skin samples from a cutaneous leishmaniasis focus, in Morocco

BACKGROUND

Cutaneous leishmaniasis (CL) is an infectious disease caused by various species of Leishmania and transmitted by several species of sand flies. CL is among the most neglected tropical diseases, and it has represented a major health threat over the past 20 years in Morocco. The main objectives of this study were to identify relevant sand fly species and detect Leishmania infection in the most prevalent species and patient skin samples in Taza, a focus of CL in North-eastern Morocco.

METHODOLOGY AND FINDING

A total of 3672 sand flies were collected by CDC miniature light traps. Morphological identification permitted the identification of 13 species, namely 10 Phlebotomus species and 3 Sergentomyia species. P. longicuspis was the most abundant species, comprising 64.08% of the total collected sand flies, followed by P. sergenti (20.1%) and P. perniciosus (8.45%). Using nested-kDNA PCR, seven pools of P. sergenti were positive to Leishmania tropica DNA, whereas 23 pools of P. longicuspis and 4 pools of P. perniciosus tested positive for Leishmania infantum DNA. The rates of P. longicuspis and P. perniciosus Leishmania infection were 2.51% (23/915) and 7.27% (4/55), respectively, whereas the infection prevalence of P. sergenti was 3.24%. We also extracted DNA from lesion smears of 12 patients suspected of CL, among them nine patients were positive with enzymatic digestion of ITS1 by HaeIII revealing two profiles. The most abundant profile, present in eight patients, was identical to L. infantum, whereas L. tropica was found in one patient. The results of RFLP were confirmed by sequencing of the ITS1 DNA region.

CONCLUSION

This is the first molecular detection of L. tropica and L. infantum in P. sergenti and P. longicuspis, respectively, in this CL focus. Infection of P. perniciosus by L. infantum was identified for the first time in Morocco. This study also underlined the predominance of L. infantum and its vector in this region, in which L. tropica has been considered the causative agent of CL for more than 20 years.

New epidemiological pattern of cutaneous leishmaniasis in two pre-Saharan arid provinces, southern Morocco

Three Leishmania species are responsible of cutaneous leishmaniasis (CL) in Morocco. Zoonotic CL due to Leishmania major and Leishmania infantum, the first is known as established in the eastern arid regions, whereas the latter evolves sporadically, especially in the North. While Leishmania tropica, classically considered anthroponotic, is endemic in the semi-arid regions and is largely distributed throughout the country. The aim of this study was to identify the Leishmania species causing CL in two Provinces in arid pre-Saharan region known as zoonotic CL foci, and to contribute an update to the national data concerning the distribution of Leishmania species in both regions. The recruitment of patients was done in six localities in Ouarzazate and Zagoura provinces in 2015 and 2016. Out of 81 samples collected, 66 were positive (81%) by ITS1-PCR amplification of Leishmania DNA extracted from stained smears. The highest rate of Leishmania infection was registered in children aged 9 years or less (71,2%). The ITS1-PCR- RFLP analysis revealed the predominance of L. major infecting 52 patients (79%), followed by L. tropica in 12 patients (18%) and L. infantum in 2 patients who had no history of travel outside the studied area (3%). The sequencing of the ITS1 of both L. infantum, showed 100% similarities with L. infantum strains isolated from dogs and visceral leishmaniasis patients from the south and north of Morocco. The coexistence of the 3 Leishmania species in the same focus, and the difficult distinction of infections associated to the different Leishmania species based only on clinical lesions' aspects complicate the diagnosis and then the national control strategy, as well as the therapeutic management. The epidemiological pattern of CL in the studied areas appears to have changed during the last decades, from a predominant zoonotic CL caused by L. major to a polymorphic disease that can be due to any of the 3 Leishmania species. The expansion of L. infantum and L. tropica in southern parts of Morocco, calls for in depth epidemiological investigations for a better understanding of the CL situations in Southern parts of the country and for an assessment of the climate impact and environment changes on the leishmaniasis transmission system.

Intraspecific genetic variability in a population of Moroccan Leishmania infantum revealed by PCR-RFLP of kDNA minicircles

In Morocco, Leishmania infantum is the main etiologic agent of human and canine visceral leishmaniasis (VL). This species has been proven to be an opportunistic agent in HIV+ patients and is also responsible of sporadic cutaneous leishmaniasis (CL).This work aims to evaluate the genetic variability of Moroccan L. infantum strains based on PCR-RFLP analysis of the kinetoplastid DNA (kDNA) minicircles. A total of 75 DNA samples extracted from positive Giemsa-stained smears (n=32) and from L. infantum cultures (n=43) was studied. The samples have been taken from VL patients infected (n=7) or not (n=56) by HIV, patients with CL (n=2) and finally from infected dogs (n=10). An hypervariable region of kDNA was amplified using the primers MC1 and MC2; the PCR products were digested separately by a panel of nine restriction enzymes. The presence or absence of restriction fragments was scored in a binary matrix and the SplitsTree4 software was used for the construction of a Neighbor-Net network. Moroccan L. infantum population showed an important level of variability with the identification of 6 genotypes. For each genotype a PCR product was sequenced, confirming the presence of all the expected restriction sites. The predominant profile was the genotype B. A new genotype, named Q was detected for the first time, whereas the four other genotypes (G, K, N and O) were reported sporadically in the Mediterranean basin. The Neighbor-Net network segregates our L. infantum population into 3 clusters: Cluster I includes genotype B, cluster II grouping the genotypes O, Q and G and finally the cluster III contains the genotype N. The kDNA-PCR-RFLP assay is suitable for use directly on biological samples; it reveals an important degree of genetic variability among L. infantum strains even those belonging to the same zymodeme what is of great epidemiological interest.