IMMUNE RESPONSE IN PYTHIOSIS PATIENTS TREATED WITH PYTHIUM INSIDIOSUM ANTIGEN (PIA)

Abstract

Immunotherapy using Pythium insidiosum antigen (PIA) is one of the combination treatment for P. insidiosum infected patients along with amputation and certain antifungal agents. The protocol of first prime (day0) after diagnosis and six booster doses (at 0.5, 1, 1.5, 3, 6, 12 months; mo.) along a year period were performed based on previous study. The switching of T-helper2 (Th2) to Th1 after immunotherapy along with the clinical improvement in equine and rabbit models were revealed whereas studies in human are very limited. To investigate the immune response in PIA treated pythiosis patients, cytokine profile (CMI response), P. insidiosum specific antibody; Pi-Ab (HMI response) and (1->3)-β-D-glucan (polysaccharide found in P. insidiosum’s cell wall component and PIA) in serum were examined before prime dose and each booster. Here, vascular and ocular pythiosis treated with immunotherapy during January 2011- July 2016 was recruited in this study. Among fifty vascular cases recruited in this study, the correlation between the tested parameters and the clinical outcome was found. The switching of Th2 (IL-4, IL-5) to Th1 (IFN-γ) cytokines along with the increasing of IL-10, IL-17 after PIA immunotherapy were found in patients with no sign of disease recurrent. Regarding HMI aspect, all of them demonstrated high constant level (ELISA value; EV>6) of Pi-Ab together with the decreasing trend of (1,3)-β-D-glucan level. Regarding, thirty ocular pythiosis, local infection, were enrolled in this study. Very less immune response was showed after infection. However, it clearly showed that both CMI and HMI were activated after PIA treatment even no correlation was found between the tested parameters and the clinical outcome.