Correlation of Genetic Heterogeneity with Cytopathological and Epidemiological Findings of <b><i>Leishmania major</i></b> Isolated from Cutaneous Leishmaniasis in Southern Iran

Abstract

Objective: Cutaneous leishmaniasis (CL) has recently grown into a major public health problem in 88 countries of the world, including Iran. It is a polymorphic disease which may show various clinicopathological features. Although the effect of the genetic diversity of the parasite has been demonstrated as one of the factors influencing clinical manifestations in CL, no data exist regarding the genetic variation of Leishmania major and its microscopical features. Study Design: Fine-needle aspiration, touch smears and the histological sections of 100 patients were examined for Leishmania amastigotes, using Giemsa and hematoxylin and eosin. Diverse types of inflammatory cells in the 40 positive and 5 negative smears were differentiated. Kinetoplast DNA (kDNA) was amplified using nested PCR and subsequently sequenced. Sequencing analysis of the amplified kDNA was used to investigate the genetic variations among L. major isolates and to correlate the findings with microscopical features and geographical origins. Results: The quantified amastigote density in the 40 positive touch smears was blindly classified by 3 observers. Grade I, II, III and IV had 7, 13, 9 and 11 cases, respectively. The microscopical features, the mean percentage of neutrophils, lymphocytes and other inflammatory cells, and the leishmanial density of the grades and negative cytopathological samples were contrasting. kDNA amplification of L. major was detected from the cutaneous lesion, and 21 of these amplicons were successfully sequenced. Conclusions: These results indicate that L. major strains causing CL in southern Iran are genetically diverse; furthermore, a correlation between the genetic heterogeneity of the parasite, the microscopical manifestation and the geographical regions of the disease in humans was found.

Intra-Species Diversity of Leishmania major and L. tropica from Clinical Isolates of Cutaneous Leishmaniasis in Southwest Iran Inferred by ITS1-rDNA

“…In addition, by using kDNA, CL causing strains of L. major in southern Iran have a significant genetic variation (26).…”

Leishmania cytochrome b gene sequence polymorphisms in southern Iran: relationships with different cutaneous clinical manifestations

“…A high degree of genetic polymorphisms in Leishmania parasites based on ITS1 and kDNA genes has been reported previously in Iran [58–62], and in the neighboring country of Afghanistan [63, 64]. In a preceding study by Baghaei, mutual connection between the genetic heterogeneity of L. major and clinical presentations of ZCL in Isfahan, Iran based on PCR-RFLP of ITS gene in the ribosomal operon, has been investigated [58].…”

“…In addition, substantial heterogeneity has been studied and reported within the ITS gene of strains of L. tropica [59, 64, 68, 69]. Oryan et al [61] and Shirian et al [62] assessed the heterogeneity of L. major causing CL based on sequencing of kDNA and showed a high genetic diversity of the parasite and correlations among the geographical origin and the clinical outcomes of the disease. Moreover, conspicuous genetic variability has been exhibited within the Nagt gene amidst L. tropica , L. major , and L. infantum strains [70, 71], and by RAPD-PCR among L. major and L. infantum strains [72–74].…”

Expression of Cytokine Genes in Leishmania major-Infected BALB/c Mice Treated with Mesenchymal Stem Cells

“…The factors influencing the difference in clinical symptoms of CL are not entirely apparent; however, the genetic diversity of the parasite is a known factor influencing the clinical manifestations [2]. In Iran, L. major strains causing CL showed genetic diversity, microscopical manifestation in human lesions correlated with the genetic heterogeneity of the parasite [3]. Genetic characteristics of the parasite such as the relationship between polymorphism in interleukin 4 gene promoter and CL clinical manifestation [4] or the molecular typing and phylogenetic analysis of Leishmania isolates from healing, and nonhealing patients [5] can be helpful in the assessment of the patient's response to treatments.…”