A 38-year-old male patient from Minas Gerais, Brazil, suffering from ankylosing spondylitis and psoriasis who was been treated with methotrexate (15 mg per week) and adalimumab (40 mg every other week) developed three ulcers on his left arm after two years of treatment (Figure 1).

Figure 1: Ulcers caused by L. (L.) infantum before treatment with pentavalent antimony

No other symptoms such as fever or weight loss were reported. The physical examination revealed no mucous lesions or hepatosplenomegaly. The blood count, electrolytes, liver and kidney function tests were normal. The leishmanin skin test was positive (19×9 mm) and parasite culture in Novy-Mac Neal-Nicolle (NNN) medium was positive for Leishmania. Indirect immunofluorescence was negative. Leishmania (Leishmania) infantum was identified by PCR-RFLP from the patient’s skin biopsy sample, which was confirmed by direct sequencing of the PCR product. HIV serology was negative. Histopathological examination showed lymphohistiocytic infiltrate with granulomas (Figure 2).

Figure 2: Histopathological examination showed lymphohistiocytic dermal infiltrate with granulomas

The patient was treated with N-methyl-glucamine (20 mgSbV/kg/day) for 20 days with interruption of adalimumab and methotrexate during therapy (Figure 3). Although the treatment was discontinued for a week, due to elevation of transaminases (TGO 48 U/L and TGP 62 U/L) the lesions presented clinical cure after the end of therapy.

Figure 3: The ulcers caused by Leishmania (Leishmania) infantum during the treatment with pentavalent antimonal

In the Northern region of Brazil more than 90% of the Cutaneous Leishmaniasis (CL) are caused by Leishmania (Viannia) guyanensis and in other regions 80% by Leishmania (Viannia) braziliensis and 20% by Leishmania (Leishmania) amazonensis [1,2]. The patient is from the northern region of the state of Minas Gerais where Leishmania (Viannia) braziliensis is the main causative agent of CL and it is also an endemic area of visceral leishmaniasis (VL) caused by Leishmania (Leishmania) infantum. In the Americas Leishmania (Leishmania) infantum also known as Leishmania (Leishmania) chagasi is the most commonly species involved in cases of VL and has been occasionally associated with manifestations of CL. These cases are classified as post-kala-azar dermal leishmaniasis that usually occurs after treatment of VL as non-ulcerated papular lesions all over the skin, and rarely as the first manifestation of VL. To date no Brazilian cases of isolated cutaneous lesions caused by viscerotropic Leishmania species had been reported.

The fact that Leishmania (Leishmania) infantum may cause isolated CL suggests that immune response is crucial to determine the course of infection [3]. Studies have demonstrated that viscerotropic species in Honduras and the Mediterranean region showed low sensitivity to the action of complement, high infectivity and survival in macrophages when compared to dermotrophic strains [4]. The size of the inoculum and the inoculation route also appear to be important in the clinical spectrum of the disease [4]. High levels of intravenously inoculum were associated with visceralization by Leishmania (Leishmania) infantum strains in BALB/c mice genetically susceptible [4].

The use of anti-TNF alpha to treat cutaneous disorders such as psoriasis has become increasingly common. The aim of this strategy is to reduce cutaneous immunologic response and heal inflammatory lesions. This kind of therapy is associated with opportunistic infections especially those where granuloma formation plays an important role in the host defense, such as cutaneous tuberculosis and leishmaniasis [4]. Cases reported in Spain of patients treated with adalimumab who developed CL and studies on the immunopathogenesis of the disease suggest that the formation of granulomas in these patients may be related to the induction of Th17 immune response and activation of Toll-like receptor-9 (TLR9) by Leishmania [5].

Despite theTh1 response is classically associated with protection against Leishmania recent studies showed that the production of cytokines related to Th17 lymphocyte activation also appears to be protective [6-8]. The Th17 cells are CD4+ T lymphocytes that produce pro-inflammatory IL-17 primarily by inducing the expression of several inflammatory mediators, and recruitment of neutrophils [9]. Experimental models have shown that a pro-inflammatory action is related to defence against a variety of infectious diseases [7,10,11]. Dendritic cell sand macrophages are capable of responding to IL-17 stimulation with increased production of IL-12, IFN-gamma and nitric oxide, leading to killing of intracellular pathogens [12].

Several aspects of the initial steps of the immune response after Leishmania infection are unknown. The signaling pathway of Toll-like receptors (TLRs) is one of the first systems of defense against Leishmania [13,14]. After the recognition of specific pathogen associated molecular patterns (PAMPs), TLRs trigger the NF-B releasing which passes into the nucleus and promotes the transcription and synthesis of pro-inflammatory cytokines [13,14].

Recently, TLR9 has been described in a higher proportion in the granulomas produced by Leishmania (Viannia) braziliensis and it was concluded that TLR9 is important to develop and maintain the granulomas [5,13]. It is likely that Leishmania DNA fragments can bind to TLR9 in macrophages and dendritic cells, activating them and acting, as described in mycobacteria, causing pulmonary granulomatous response in rat models [5]. TLR9 could regulate Th17 activation and increase the secretion of IL-17A promoting the formation and maintenance of granulomas mediated by neutrophils [5].

We described a case of CL without visceral manifestation caused by Leishmania (Leishmania) infantum with formation of granulomas in a patient using anti-TNF alpha and methotrexate, both immunosuppressive drugs. In this case, the absence of visceralization could be explained by the presence of cellular immunity demonstrated by the positivity of leishmanin skin test, the granulomatous infiltrate in the histopathological examination and adequate response to the treatment [15]. Cases of CL worsened or triggered during the use of corticosteroids and immunosuppressive drugs such as methotrexate are frequent, however, in the present case the biological therapy may have been the main factor triggering the disease, since it is clearly associated with an increased risk of infections. We strongly believe that this patient was carrying on an unapparent infection by Leishmania (Leishmania) infantum and that anti-TNF alpha had been the trigger for the clinical manifestation of the disease.

To our knowledge this is the first report of human CL caused by Leishmania (Leishmania) infantum without visceral manifestation in Brazil, with only preceding canine VL-associated CL and atypical cases of CL by viscerotropic species [16].

Leishmania infection in patients treated with anti-TNF alpha has to be remembered as an opportunistic disease associated with biological therapies, especially in endemic countries. The role of anti-TNF alpha to CL by viscerotropic species is unclear.