A comprehensive systematic review of leishmaniasis in patients undergoing drug-induced immunosuppression for the treatment of dermatological, rheumatological and gastroenterological diseases

The immunomicrotope of Leishmania control and persistence

Leishmania is an intracellular protozoan transmitted by sand fly vectors; it causes cutaneous, mucocutaneous, or visceral disease. Its growth and survival are impeded by type 1 T helper cell responses, which entail interferon (IFN)-γ-mediated macrophage activation. Leishmania partially escapes this host defense by triggering immune cell and cytokine responses that favor parasite replication rather than killing. Novel methods for in situ analyses have revealed that the pathways of immune control and microbial evasion are strongly influenced by the tissue context, the micro milieu factors, and the metabolism at the site of infection, which we collectively term the 'immunomicrotope'. Understanding the components and the impact of the immunomicrotope will enable the development of novel strategies for the treatment of chronic leishmaniasis.

Recurrent leishmaniasis infection isolated in the pleural fluid

We present a rare case of recurrent leishmaniasis infection in a female in her 80s who re-presented with a pleural effusion. The patient was initially investigated as an outpatient for cytopenia and underwent a bone marrow biopsy which subsequently diagnosed visceral leishmaniasis. Following full treatment, and apparent recovery, she re-presented with pleural effusion, hypoalbuminaemia and cytopenia. Leishmania was eventually isolated in a pleural fluid sample obtained on therapeutic drainage, and she was treated for a recurrence at a tertiary infectious disease unit. This interesting and challenging case demonstrates the importance of suspecting leishmaniasis recurrence in previously treated cases and the diagnostic benefit of pleural fluid analysis in the context of suspected leishmaniasis.

Unmet needs in the management of psoriasis in Latin America: a systematic review

BACKGROUND

Psoriasis is a chronic, systemic inflammatory disease with a worldwide prevalence of approximately 2%. Currently, despite the difficulties faced every day by patients and physicians in low-resource countries, literature describing the exact needs of psoriasis treatment in Latin America remains scarce.

OBJECTIVE

To investigate the unmet needs in psoriasis treatment in Latin America.

METHODS

The authors conducted a systematic review following PRISMA statements in PubMed, Embase, and LILACS of studies published from January 2011 to March 2021 addressing challenges in psoriasis treatment in Latin America.

RESULTS

The search strategy identified 3,837 articles, of which 19 were included in the final analysis. Most were from Brazil (58%; n=11), all were observational, and most were cross-sectional (84%; n=16). Difficulties faced by psoriasis patients in Latin America included the high prevalence of opportunistic and endemic infections (42% of the studies addressed this matter; n=8), delay in diagnosis (5%; n=1), work productivity impairment (16%; n=3), limited access to medication/medical care (37%; n=7), poor adherence to treatment (5%; n=1) and poor adherence to guidelines (11%; n=2).

STUDY LIMITATIONS

Number and quality of studies currently available on this subject.

CONCLUSIONS

Current psoriasis guidelines do not always account for epidemiological, financial, and cultural characteristics. Most studies available are from Brazil, which might not accurately represent Latin America as a whole. In a region where neglected diseases and scarce resources remain a reality, it is imperative that dermatological training be offered to primary care providers, allowing for standardized conduct and earlier diagnosis.

Potential selection of antimony and methotrexate cross-resistance in Leishmania infantum circulating strains

BACKGROUND

Visceral leishmaniasis (VL) resolution depends on a wide range of factors, including the instauration of an effective treatment coupled to a functional host immune system. Patients with a depressed immune system, like the ones receiving methotrexate (MTX), are at higher risk of developing VL and refusing antileishmanial drugs. Moreover, the alarmingly growing levels of antimicrobial resistance, especially in endemic areas, contribute to the increasing the burden of this complex zoonotic disease.

PRINCIPAL FINDINGS

To understand the potential links between immunosuppressants and antileishmanial drugs, we have studied the interaction of antimony (Sb) and MTX in a Leishmania infantum reference strain (LiWT) and in two L. infantum clinical strains (LiFS-A and LiFS-B) naturally circulating in non-treated VL dogs in Spain. The LiFS-A strain was isolated before Sb treatment in a case that responded positively to the treatment, while the LiFS-B strain was recovered from a dog before Sb treatment, with the dog later relapsing after the treatment. Our results show that, exposure to Sb or MTX leads to an increase in the production of reactive oxygen species (ROS) in LiWT which correlates with a sensitive phenotype against both drugs in promastigotes and intracellular amastigotes. LiFS-A was sensitive against Sb but resistant against MTX, displaying high levels of protection against ROS when exposed to MTX. LiFS-B was resistant to both drugs. Evaluation of the melting proteomes of the two LiFS, in the presence and absence of Sb and MTX, showed a differential enrichment of direct and indirect targets for both drugs, including common and unique pathways.

CONCLUSION

Our results show the potential selection of Sb-MTX cross-resistant parasites in the field, pointing to the possibility to undermine antileishmanial treatment of those patients being treated with immunosuppressant drugs in Leishmania endemic areas.

Immunosuppressants alter the immune response associated with Glucantime® treatment for Leishmania infantum infection in a mouse model

Background

Immunosuppression is a major risk factor for the development of visceral leishmaniasis (VL). The number of patients receiving immunosuppressant drugs such as TNF antagonist (anti-TNF) and methotrexate (MTX) is increasing. In these patients, VL is more severe, their response to treatment poorer, and they are at higher risk of relapse, a consequence (largely) of the poor and inappropriate immune response they develop.

Objectives

To examine the effect of immunosuppressive treatment on the host immune response and thus gain insight into the reduced efficacy of pentavalent antimonials in these patients. Experiments were performed using BALB/c mice immunosuppressed with anti-TNF or MTX, infected with Leishmania infantum promastigotes, and then treated with Glucantime® at clinical doses.

Results

Immunosuppression with both agents impeded parasite elimination from the spleen and bone marrow. Low pro-inflammatory cytokine production by CD4+ and CD8+ T cells was detected, along with an increase in PD-1 and IL-10 expression by B and T cells in the immunosuppressed groups after treatment.

Conclusion

The immunosuppressed mice were unable to develop specific cellular immunity to the parasite, perhaps explaining the greater risk of VL relapse seen in pharmacologically immunosuppressed human patients.

Leishmania infantum infection after visiting southern Spain in patients on biological treatment; an observational, longitudinal, cohort study

BACKGROUND

Reports of leishmaniasis in immunosuppressed patients after visiting the Mediterranean Basin are becoming increasingly common. Still, awareness of the risk of infection and its clinical manifestations may be insufficient among healthcare professionals in the travellers' home countries.

METHODS

This observational, longitudinal study included 47 patients from Sweden with rheumatic disease and ongoing immunomodulatory treatment, who visited a rehabilitation centre in southern Spain where leishmaniasis is endemic. Patients were evaluated for clinical signs of leishmaniasis at baseline and after three years. Patients with leishmaniasis were followed for 4-5 years. The treatment outcome was assessed by clinical evaluation and determination of the cell-mediated immunological response to Leishmania by a whole blood cytokine release assay.

RESULTS

Seven patients (15%) were diagnosed with leishmaniasis. The median time from exposure to the onset of symptoms was 3 [1-17] months. The median delay between the onset of symptoms and treatment start was 9 [1-12] months. All patients with leishmaniasis responded well to treatment. Only one patient had a relapse, which occurred within the first year.

CONCLUSION

Healthcare professionals need to be aware of the increased risk of leishmaniasis for travellers who are immunosuppressed. Knowledge of the symptoms is crucial for a timely diagnosis and early treatment.

A trespasser from a foreign land? A case report of primary mucosal leishmaniasis

BACKGROUND

We report a clinically challenging and unusual case of L. donovani oral mucosal leishmaniasis.

CASE PRESENTATION

Israeli resident with a former travel to central and North Africa, with no documented or prior cutaneous lesions presented with oral lesions of the maxillary gingiva and the upper lip. A delay in diagnosis and treatment have led to progression of the maxillary gingival lesions towards the hard palatal and the soft palate that could have potentially compromised the upper airway.

CONCLUSIONS

This case highlights the importance of early diagnosis of leishmaniasis in patients with oral lesions and the laboratory workup necessary to appropriately characterize and treat the disease.

Imported leishmaniasis in travelers: a 7-year retrospective from a Parisian hospital in France

BACKGROUND

Leishmaniases are regularly seen in non-endemic areas due to the increase of international travels. They include cutaneous leishmaniases (CL) and mucocutaneous (MC) caused by different Leishmania species, and visceral leishmaniases (VL) which present with non-specific symptoms.

METHODS

We reviewed all consecutive leishmaniasis cases seen between September 2012 and May 2020. The diagnostic strategy included microscopy after May-Grünwald-Giemsa staining, a diagnostic quantitative PCR (qPCR) assay, and species identification based on sequencing of the cytochrome b gene.

RESULTS

Eighty-nine patients had a definitive leishmaniasis diagnosis. Nine patients had VL with Leishmania infantum. Eighty patients had CL. Twelve patients acquired CL after trips in Latin America (7 Leishmania guyanensis, 2 Leishmania braziliensis, 2 Leishmania mexicana, and 1 Leishmania panamensis). Species could be identified in 63 of the 68 CLs mainly after travel in North Africa (59%) with Leishmania major (65%), Leishmania tropica/killicki (24%), and L. infantum (11%), or in West Sub-Saharan Africa (32%), all due to L. major. The median day between appearance of the lesions and diagnosis was 90 [range 60-127].

CONCLUSIONS

Our diagnostic strategy allows both positive diagnoses and species identifications. Travelers in West Sub-Saharan Africa and North Africa should be better aware of the risk of contracting leishmananiasis.