SLC11A1 polymorphisms and host susceptibility to cutaneous leishmaniasis in Pakistan.

BACKGROUND: The vector-borne cutaneous leishmaniasis (CL) is endemic in several regions of Pakistan mainly affecting poor populations. Host genetic factors, particularly SLC11A1 (solute carrier transmembrane protein) within macrophages, play a crucial role in disease pathology and susceptibility. Association of SLC11A1 with cutaneous leishmaniasis, a neglected tropical disease, is not well established. Inconsistencies have been observed within different populations worldwide with respect to genetic susceptibility. This study was designed to investigate genetic variation(s) in SLC11A1 and to assess possible association with cutaneous leishmaniasis in Pakistan. RESULTS: Eight polymorphisms (rs2276631, rs3731864, rs2290708, rs2695342, rs201565523, rs17215556, rs17235409, rs17235416) were genotyped across SLC11A1 in 274 patients and 119 healthy controls. Six polymorphisms were studied by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) and sequencing. Two single nucleotide polymorphisms were analyzed with newly designed semi-nested PCR assays. Case-control analysis showed no association between selected polymorphisms in SLC11A1 and cutaneous leishmaniasis. No significant difference was observed in the distribution of alleles between leishmaniasis patients and healthy individuals. Strong pairwise linkage disequilibrium was observed between rs2276631 and rs2290708 (r 2 = 64); and rs17235409 and rs17235416 (r 2 = 78). CONCLUSIONS: This study shows that genetic variations in the candidate gene SLC11A1 do not affect susceptibility to cutaneous leishmaniasis in the sample population from Pakistan.

Cutaneous Leishmaniasis in Khyber Pakhtunkhwa Province of Pakistan: Clinical Diversity and Species-Level Diagnosis.

This study primarily aimed to identify the causative species of cutaneous leishmaniasis (CL) in the Khyber Pakhtunkhwa Province of Pakistan and to distinguish any species-specific variation in clinical manifestation of CL. Diagnostic performance of different techniques for identifying CL was assessed. Isolates of Leishmania spp. were detected by in vitro culture, polymerase chain reaction (PCR) on DNA extracted from dried filter papers and microscopic examination of direct lesion smears from patients visiting three major primary care hospitals in Peshawar. A total of 125 CL patients were evaluated. Many acquired the disease from Peshawar and the neighboring tribal area of Khyber Agency. Military personnel acquired CL while deployed in north and south Waziristan. Leishmania tropica was identified as the predominant infecting organism in this study (89.2%) followed by Leishmania major (6.8%) and, unexpectedly, Leishmania infantum (4.1%). These were the first reported cases of CL caused by L. infantum in Pakistan. PCR diagnosis targeting kinetoplast DNA was the most sensitive diagnostic method, identifying 86.5% of all samples found positive by any other method. Other methods were as follows: ribosomal DNA PCR (78.4%), internal transcribed spacer 2 region PCR (70.3%), culture (67.1%), and microscopy (60.5%). Clinical examination reported 14 atypical forms of CL. Atypical lesions were not significantly associated with the infecting Leishmania species, nor with "dry" or "wet" appearance of lesions. Findings from this study provide a platform for species typing of CL patients in Pakistan, utilizing a combination of in vitro culture and molecular diagnostics. Moreover, the clinical diversity described herein can benefit clinicians in devising differential diagnosis of the disease.

CC chemokine receptor 5 Δ32 polymorphism: association analysis and allele distribution among cutaneous leishmaniasis patients from Pakistan.

BACKGROUND: Human immunodeficiency virus (HIV)/leishmaniasis coinfection is a matter of deep concern worldwide. CC chemokine receptor 5 (CCR5) functions as a co-receptor for HIV entry into host immune cells with an elevated expression observed during leishmaniasis, promoting parasite persistence. A 32 bp deletion (Δ32) in the CCR5 gene provides protection against HIV infection and increased resistance to Leishmania infection. METHODS: In this study, CCR5-Δ32 distribution within Pakistani population with cutaneous leishmaniasis was investigated to evaluate genetic susceptibility to HIV infection. CCR5-Δ32 polymorphism was analyzed in 276 leishmaniasis patients and 119 uninfected healthy controls. Genotypic and allelic frequencies were evaluated and tested for Hardy-Weinberg equilibrium (HWE). RESULTS: The overall Δ32 allele frequency was 6.58% of the population (n = 395). There was a significant difference (p < 0.05) in the geographical distribution of Δ32 allele which was higher in the northern region of the country when compared with the south. Five individuals were identified to be homozygous for the Δ32 allele which has not been reported before from Pakistan. However, no significant association was observed between CCR5-Δ32 and cutaneous leishmaniasis. CONCLUSION: The higher frequency of CCR5 wild-type allele among leishmaniasis patients may suggest an increased risk of HIV infection and also support its facilitative role in Leishmania infection.