Review
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World J Immunol. Jul 27, 2014; 4(2): 88-97
Published online Jul 27, 2014. doi: 10.5411/wji.v4.i2.88
Update on pythiosis immunobiology and immunotherapy
Érico S Loreto, Juliana SM Tondolo, Régis A Zanette, Sydney H Alves, Janio M Santurio
Érico S Loreto, Juliana SM Tondolo, Régis A Zanette, Sydney H Alves, Janio M Santurio, Department of Microbiology and Parasitology, Universidade Federal de Santa Maria, Santa Maria, RS 97105-900, Brazil
Érico S Loreto, Juliana SM Tondolo, Régis A Zanette, Sydney H Alves, Janio M Santurio, Programa de Pós-graduação em Ciências Farmacêuticas, Universidade Federal de Santa Maria, Santa Maria, RS 97105-900, Brazil
Author contributions: Loreto ÉS, Tondolo JSM, Zanette RA, Alves SH and Santurio JM solely contributed to this paper.
Supported by The Coordenação de Aperfeiçoamento de Pessoal de Nível Superior, Brazil, No. CAPES-AUX PE-PNPD 743/2012
Correspondence to: Dr. Janio M Santurio, Department of Microbiology and Parasitology, Universidade Federal de Santa Maria, Av. Roraima nº 1000, Prédio 20, sala 4139, Santa Maria, RS 97105-900, Brazil. janio.santurio@gmail.com
Telephone: +55-55-32208906 Fax: +55-55-32208906
Received: March 27, 2014
Revised: May 6, 2014
Accepted: June 10, 2014
Published online: July 27, 2014
Processing time: 121 Days and 20.3 Hours
Abstract

Pythiosis is an invasive, ulcerative, pyogranulomatous disease caused by Pythium insidiosum, a fungus-like oomycete that has been reported to affect humans, horses, dogs, and other mammals mainly in tropical and subtropical areas of the world. The disease is characterized by an eosinophilic granulomatous and a Th2 immune response which in turn helps to protect the fungus from the host cells. Pythiosis can present clinically in subcutaneous, gastrointestinal, and vascular tissues or in a systemically disseminated form depending on the species and site of infection. Changes in iron metabolism and anemia are commonly observed. The diagnosis is accomplished through clinical and pathological features, laboratory characteristics of cultures, serological and molecular tests. Treatment includes radical surgery, antimicrobial drugs, immunotherapy or a combination of these treatments. Immunotherapy is a practical and non-invasive alternative for treating pythiosis which is believed to promote a switch from a Th2 to Th1 immune response, resulting in a favorable clinical response. This therapy has demonstrated cure rates above 70% and 55% in horses and humans but low cure rates in dogs and cats. Despite the curative properties of this type of immunotherapy, the antibodies that are produced do not prevent host reinfection. Thus, development of effective adjuvants and new diagnostic techniques for early disease diagnosis are of utmost importance. The aim of this review was to promote pythiosis awareness and to provide an update about the immunotherapy and immunobiology of this disease.

Keywords: Pythium insidiosum; Treatment; Pythiosis; Immunotherapy; Pathogenesis

Core tip: Pythiosis is a life-threatening disease for which there is no gold standard chemotherapy. Immunotherapy derived from killed mycelium from Pythium insidiosum is a non-invasive therapy that has demonstrated cure rates above 90% when associated with the surgical removal of the lesions and early disease diagnosis.