Effect of topical paromomycin on cell-mediated immunity during cutaneous leishmaniasis

Interventions for Old World cutaneous leishmaniasis

BACKGROUND

Cutaneous leishmaniasis, caused by a parasitic infection, is considered one of the most serious skin diseases in many low- and middle-income countries. Old World cutaneous leishmaniasis (OWCL) is caused by species found in Africa, Asia, the Middle East, the Mediterranean, and India. The most commonly prescribed treatments are antimonials, but other drugs have been used with varying success. As OWCL tends to heal spontaneously, it is necessary to justify the use of systemic and topical treatments. This is an update of a Cochrane Review first published in 2008.

OBJECTIVES

To assess the effects of therapeutic interventions for the localised form of Old World cutaneous leishmaniasis.

SEARCH METHODS

We updated our searches of the following databases to November 2016: the Cochrane Skin Specialised Register, CENTRAL, MEDLINE, Embase, and LILACS. We also searched five trials registers and checked the reference lists of included studies for further references to relevant randomised controlled trials (RCTs). We wrote to national programme managers, general co-ordinators, directors, clinicians, WHO-EMRO regional officers of endemic countries, pharmaceutical companies, tropical medicine centres, and authors of relevant papers for further information about relevant unpublished and ongoing trials. We undertook a separate search for adverse effects of interventions for Old World cutaneous leishmaniasis in September 2015 using MEDLINE.

SELECTION CRITERIA

Randomised controlled trials of either single or combination treatments in immunocompetent people with OWCL confirmed by smear, histology, culture, or polymerase chain reaction. The comparators were either no treatment, placebo/vehicle, and/or another active compound.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed trials for inclusion and risk of bias and extracted data. We only synthesised data when we were able to identify at least two studies investigating similar treatments and reporting data amenable to pooling. We also recorded data about adverse effects from the corresponding search.

MAIN RESULTS

We included 89 studies (of which 40 were new to this update) in 10,583 people with OWCL. The studies included were conducted mainly in the Far or Middle East at regional hospitals, local healthcare clinics, and skin disease research centres. Women accounted for 41.5% of the participants (range: 23% to 80%). The overall mean age of participants was 25 years (range 12 to 56). Most studies lasted between two to six months, with the longest lasting two years; average duration was four months. Most studies were at unclear or high risk for most bias domains. A lack of blinding and reporting bias were present in almost 40% of studies. Two trials were at low risk of bias for all domains. Trials reported the causative species poorly.Here we provide results for the two main comparisons identified: itraconazole (200 mg for six to eight weeks) versus placebo; and paromomycin ointment (15% plus 10% urea, twice daily for 14 days) versus vehicle.In the comparison of oral itraconazole versus placebo, at 2.5 months' follow up, 85/125 participants in the itraconazole group achieved complete cure compared to 54/119 in the placebo group (RR 3.70, 95% CI 0.35 to 38.99; 3 studies; 244 participants). In one study, microbiological or histopathological cure of skin lesions only occurred in the itraconazole group after a mean follow-up of 2.5 months (RR 17.00, 95% CI 0.47 to 612.21; 20 participants). However, although the analyses favour oral itraconazole for these outcomes, we cannot be confident in the results due to the very low certainty evidence. More side effects of mild abdominal pain and nausea (RR 2.36, 95% CI 0.74 to 7.47; 3 studies; 204 participants) and mild abnormal liver function (RR 3.08, 95% CI 0.53 to 17.98; 3 studies; 84 participants) occurred in the itraconazole group (as well as reports of headaches and dizziness), compared with the placebo group, but again we rated the certainty of evidence as very low so are unsure of the results.When comparing paromomycin with vehicle, there was no difference in the number of participants who achieved complete cure (RR of 1.00, 95% CI 0.86, 1.17; 383 participants, 2 studies) and microbiological or histopathological cure of skin lesions after a mean follow-up of 2.5 months (RR 1.03, CI 0.88 to 1.20; 383 participants, 2 studies), but the paromomycin group had more skin/local reactions (such as inflammation, vesiculation, pain, redness, or itch) (RR 1.42, 95% CI 0.67 to 3.01; 4 studies; 713 participants). For all of these outcomes, the certainty of evidence was very low, meaning we are unsure about these results.Trial authors did not report the percentage of lesions cured after the end of treatment or speed of healing for either of these key comparisons.

AUTHORS' CONCLUSIONS

There was very low-certainty evidence to support the effectiveness of itraconazole and paromomycin ointment for OWCL in terms of cure (i.e. microbiological or histopathological cure and percentage of participants completely cured). Both of these interventions incited more adverse effects, which were mild in nature, than their comparisons, but we could draw no conclusions regarding safety due to the very low certainty of the evidence for this outcome.We downgraded the key outcomes in these two comparisons due to high risk of bias, inconsistency between the results, and imprecision. There is a need for large, well-designed international studies that evaluate long-term effects of current therapies and enable a reliable conclusion about treatments. Future trials should specify the species of leishmaniasis; trials on types caused by Leishmania infantum, L aethiopica, andL donovani are lacking. Research into the effects of treating women of childbearing age, children, people with comorbid conditions, and those who are immunocompromised would also be helpful.It was difficult to evaluate the overall efficacy of any of the numerous treatments due to the variable treatment regimens examined and because RCTs evaluated different Leishmania species and took place in different geographical areas. Some outcomes we looked for but did not find were degree of functional and aesthetic impairment, change in ability to detect Leishmania, quality of life, and emergence of resistance. There were only limited data on prevention of scarring.

Interventions for Old World cutaneous leishmaniasis

BACKGROUND

Cutaneous leishmaniasis, caused by a parasitic infection, is considered one of the most serious skin diseases in many low- and middle-income countries. Old World cutaneous leishmaniasis (OWCL) is caused by species found in Africa, Asia, the Middle East, the Mediterranean, and India. The most commonly prescribed treatments are antimonials, but other drugs have been used with varying success. As OWCL tends to heal spontaneously, it is necessary to justify the use of systemic and topical treatments. This is an update of a Cochrane Review first published in 2008.

OBJECTIVES

To assess the effects of therapeutic interventions for the localised form of Old World cutaneous leishmaniasis.

SEARCH METHODS

We updated our searches of the following databases to November 2016: the Cochrane Skin Specialised Register, CENTRAL, MEDLINE, Embase, and LILACS. We also searched five trials registers and checked the reference lists of included studies for further references to relevant randomised controlled trials (RCTs). We wrote to national programme managers, general co-ordinators, directors, clinicians, WHO-EMRO regional officers of endemic countries, pharmaceutical companies, tropical medicine centres, and authors of relevant papers for further information about relevant unpublished and ongoing trials. We undertook a separate search for adverse effects of interventions for Old World cutaneous leishmaniasis in September 2015 using MEDLINE.

SELECTION CRITERIA

Randomised controlled trials of either single or combination treatments in immunocompetent people with OWCL confirmed by smear, histology, culture, or polymerase chain reaction. The comparators were either no treatment, placebo/vehicle, and/or another active compound.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed trials for inclusion and risk of bias and extracted data. We only synthesised data when we were able to identify at least two studies investigating similar treatments and reporting data amenable to pooling. We also recorded data about adverse effects from the corresponding search.

MAIN RESULTS

We included 89 studies (of which 40 were new to this update) in 10,583 people with OWCL. The studies included were conducted mainly in the Far or Middle East at regional hospitals, local healthcare clinics, and skin disease research centres. Women accounted for 41.5% of the participants (range: 23% to 80%). The overall mean age of participants was 25 years (range 12 to 56). Most studies lasted between two to six months, with the longest lasting two years; average duration was four months. Most studies were at unclear or high risk for most bias domains. A lack of blinding and reporting bias were present in almost 40% of studies. Two trials were at low risk of bias for all domains. Trials reported the causative species poorly.Here we provide results for the two main comparisons identified: itraconazole (200 mg for six to eight weeks) versus placebo; and paromomycin ointment (15% plus 10% urea, twice daily for 14 days) versus vehicle.In the comparison of oral itraconazole versus placebo, at 2.5 months' follow up, 85/125 participants in the itraconazole group achieved complete cure compared to 54/119 in the placebo group (RR 3.70, 95% CI 0.35 to 38.99; 3 studies; 244 participants). In one study, microbiological or histopathological cure of skin lesions only occurred in the itraconazole group after a mean follow-up of 2.5 months (RR 17.00, 95% CI 0.47 to 612.21; 20 participants). However, although the analyses favour oral itraconazole for these outcomes, we cannot be confident in the results due to the very low certainty evidence. More side effects of mild abdominal pain and nausea (RR 2.36, 95% CI 0.74 to 7.47; 3 studies; 204 participants) and mild abnormal liver function (RR 3.08, 95% CI 0.53 to 17.98; 3 studies; 84 participants) occurred in the itraconazole group (as well as reports of headaches and dizziness), compared with the placebo group, but again we rated the certainty of evidence as very low so are unsure of the results.When comparing paromomycin with vehicle, there was no difference in the number of participants who achieved complete cure (RR of 1.00, 95% CI 0.86, 1.17; 383 participants, 2 studies) and microbiological or histopathological cure of skin lesions after a mean follow-up of 2.5 months (RR 1.03, CI 0.88 to 1.20; 383 participants, 2 studies), but the paromomycin group had more skin/local reactions (such as inflammation, vesiculation, pain, redness, or itch) (RR 1.42, 95% CI 0.67 to 3.01; 4 studies; 713 participants). For all of these outcomes, the certainty of evidence was very low, meaning we are unsure about these results.Trial authors did not report the percentage of lesions cured after the end of treatment or speed of healing for either of these key comparisons.

AUTHORS' CONCLUSIONS

There was very low-certainty evidence to support the effectiveness of itraconazole and paromomycin ointment for OWCL in terms of cure (i.e. microbiological or histopathological cure and percentage of participants completely cured). Both of these interventions incited more adverse effects, which were mild in nature, than their comparisons, but we could draw no conclusions regarding safety due to the very low certainty of the evidence for this outcome.We downgraded the key outcomes in these two comparisons due to high risk of bias, inconsistency between the results, and imprecision. There is a need for large, well-designed international studies that evaluate long-term effects of current therapies and enable a reliable conclusion about treatments. Future trials should specify the species of leishmaniasis; trials on types caused by Leishmania infantum, L aethiopica, andL donovani are lacking. Research into the effects of treating women of childbearing age, children, people with comorbid conditions, and those who are immunocompromised would also be helpful.It was difficult to evaluate the overall efficacy of any of the numerous treatments due to the variable treatment regimens examined and because RCTs evaluated different Leishmania species and took place in different geographical areas. Some outcomes we looked for but did not find were degree of functional and aesthetic impairment, change in ability to detect Leishmania, quality of life, and emergence of resistance. There were only limited data on prevention of scarring.

A New Antileishmanial Preparation of Combined Solamargine and Solasonine Heals Cutaneous Leishmaniasis through Different Immunochemical Pathways

Little has been done during the past 100 years to develop new antileishmanial drugs. Most infected individuals live in poor countries and have a low cash income to be attractive targets to pharmaceutical corporations. Two heterosidic steroids, solamargine and solasonine, initially identified as major components of the Brazilian plant Solanum lycocarpum, were tested for leishmanicidal activity. Both alkaloids killed intracellular and extracellular Leishmania mexicana parasites more efficiently than the reference drug sodium stibogluconate. A total of 10 μM each individual alkaloid significantly reduced parasite counts in infected macrophages and dendritic cells. In vivo treatment of C57BL/6 mice with a standardized topical preparation containing solamargine (45.1%) and solasonine (44.4%) gave significant reductions in lesion sizes and parasite counts recovered from lesions. Alkaloids present different immunochemical pathways in macrophages and dendritic cells. We conclude that this topical preparation is effective and a potential new and inexpensive treatment for cutaneous leishmaniasis.

Interventions for Old World cutaneous leishmaniasis

BACKGROUND

Cutaneous leishmaniasis is caused by a parasitic infection and is considered one of the most serious skin diseases in many developing countries. Antimonials are the most commonly prescribed treatment but other drugs have been used with varying success.

OBJECTIVES

To assess the effects of treatments for Old World cutaneous leishmaniasis (OWCL).

SEARCH STRATEGY

We searched the Cochrane Skin Group Specialised Register (April 2008), the Cochrane Central Register of Controlled Trials (The Cochrane Library Issue 2, 2008), MEDLINE (2003-April 2008), EMBASE (2005-April 2008), CINAHL (1982-August 2007), LILACS (from inception to April 2008) and ongoing trials databases (August 2007).

SELECTION CRITERIA

Randomised controlled trials assessing treatments in immuno-competent people with OWCL confirmed by smear, histology, culture or polymerase chain reaction.

DATA COLLECTION AND ANALYSIS

Two authors independently assessed trial quality and extracted data.

MAIN RESULTS

We included 49 trials involving 5559 participants. Reporting quality was generally poor and only two studies contained sufficiently similar data to pool.In Leishmania major infections, there was good RCT evidence of benefit of cure around 3 months after treatment when compared to placebo for 200 mg oral fluconazole (1 RCT n = 200, RR 2.78; 95% CI 1.86, 4.16), topical 15% paromomycin + 12% methylbenzethonium chloride (PR-MBCL) (1 RCT n = 60, RR 3.09; 95% CI 1.14, 8.37) and photodynamic therapy (1 RCT n = 60, RR 7.02; 95% CI 3.80, 17.55). Topical PR-MBCL was less efficacious than photodynamic therapy (1 RCT n = 65, RR 0.44; 95% CI 0.29, 0.66). Oral pentoxifylline was a good adjuvant therapy to intramuscular meglumine antimoniate (IMMA) when compared to IMMA plus placebo (1 RCT n = 64, RR 1.63; 95% CI 1.11, 2.39)In Leishmania tropica infections, there was good evidence of benefit for the use of 200 mg oral itraconazole for 6 weeks compared with placebo (1 RCT n = 20, RR 7.00; 95% CI 1.04, 46.95), for intralesional sodium stibogluconate (1 RCT n = 292, RR 2.62; 95% CI 1.78, 3.86), and for thermotherapy compared with intramuscular sodium stibogluconate (1 RCT n = 283, RR 2.99; 95% CI 2.04, 4.37).

AUTHORS' CONCLUSIONS

Most trials have been designed and reported poorly, resulting in a lack of evidence for potentially beneficial treatments. There is a desperate need for large well conducted studies that evaluate long-term effects of current therapies. We suggest the creation of an international platform to improve quality and standardization of future trials in order to inform clinical practice.

The flow-cytometry-based evaluation of cellular immunity in cases of cutaneous leishmaniasis and healthy controls from the endemic area in southern Israel

Only limited data are available on the early immunological events associated with human cutaneous leishmaniasis (CL). In this study, peripheral-blood mononuclear cells were obtained from 66 individuals (34 patients with cutaneous lesions and 32 apparently healthy controls) who had each spent no more than 3 months in the endemic region of Qetzioth, in southern Israel. These cells' responses to Leishmania major antigen were then explored, by the flow-cytometry-based evaluation of blast transformation (BT). The lymphocytes from 17 (50%) of the patients but only one (3%) of the controls displayed BT. When, in an ELISA, most (52) of the subjects were checked for anti-L. major antibodies, none of the 22 controls investigated but 19 (63%) of the 30 patients were found seropositive. Although 14 (47%) of the 30 patients who were checked for antibodies were BT-positive, the seropositive patients were not significantly more or less likely to be BT-positive than the seronegative patients (P<0.919). These data indicate that, in CL, the hosts' cellular and humoral responses develop independently within the first 3 months post-infection, but further investigation is required to confirm this hypothesis.

Treatment of cutaneous leishmaniasis

The World Health Organization estimates that approximately 400,000 new cases of leishmaniasis occur worldwide each year. Cutaneous leishmaniasis is being encountered more frequently in the United States because of increasing travel and immigration from endemic areas. The indications for treatment and recommended treatment regimens reported in the infectious disease and dermatology literature vary widely. We examine both classic and newly developed therapeutic agents and modalities for cutaneous leishmaniasis. Proper therapy depends on species identification. New World leishmaniasis, in general, requires more aggressive therapy; parenteral antimonials are the drugs of choice. Physical modalities may suffice in most cases of Old World leishmaniasis because of its strong tendency toward spontaneous resolution.