Page 103 - GTM-3-1

Global Translational Medicine Anergy in Leishmania-associated malignancy

Figure 2. Malignant epithelial cells with abnormal mitoses characteristic Figure 4. Axial computed tomography image suggesting cervical lymph
of squamous cell carcinoma, alternating with histiocytes parasitized by node metastases, which were histopathologically confirmed.
Leishmania and abundant extracellular microorganisms (H&E, ×40).
Scale bar: 100 mm. studies have also demonstrated that patients with diffuse
cutaneous leishmaniasis showed reduced or no immune
response to Leishmania sp. antigens and no effective
cellular immune response with lymphoplasmacytic
infiltrates, which collectively indicate a sign of parasite-
mediated immunosuppression. 9,12
Potential association patterns between leishmaniasis
and malignancies have been reported, including
(1) leishmaniasis mimicking malignancies, (2) leishmaniasis
coexisting with malignancies, (3) malignancies occurring
in patients with leishmaniasis, and (4) leishmaniasis
occurring in patients with cancer. Our case fits into the
12
description of category (3).
Failure to mount a protective cell-mediated immune
response and induction of a regulatory response by the
parasite are currently the two most plausible mechanisms
Figure 3. Histological section of the skin nodules showing numerous
Leishmania amastigotes (arrow) infiltrating into the cytoplasm of underlying the development of diffuse cutaneous
9,16
histiocytes (H&E, ×100). Scale bar: 50 mm. leishmaniasis. In this case, the role of the host immune
response in disease development is implicated in the
The mechanism responsible for the development of development of massive SCCs during active infection.
cutaneous neoplasms in patients with leishmaniasis has Although the virulence factors involved are not well
not yet been fully elucidated. The association between characterized, Leishmania sp. is capable of suppressing
12
these two diseases is not coincidental given the number the cellular immune response, leading to anergy. The
16
of published cases. Chronic inflammation that occurs exact defective state that results in anergy to the parasite
during active infection or during the healing process offers is not clear, but may be attributed to the release of
a plausible link between skin pathology and parasitic immunosuppressive cytokines; increased macrophage
disease. In the present case, persistent anergy stands as expression of transforming growth factor beta occurs
13
a potential factor influencing the development of skin when exposed to Leishmania sp. antigens. This permissive
16
cancer in active leishmaniasis lesions which had been environment shaped by the anergy may also be involved
affecting the patient for more than 10 years. Corroborating in the development and progression of SCC. Additional
such a postulation is the increased risk of developing virulence factors include the expression of arginase I and
cancer that has been reported in immunosuppressed as enzymes involved in the synthesis of prostaglandins and
well as in immunocompetent patients. 8,13-15 The previous polyamines. 17

Volume 3 Issue 1 (2024) 3 https://doi.org/10.36922/gtm.2281