One of the types of external human parasites is a follicular scab called Demodex. Demodicosis is a skin disease in human and canine. Demodex mites feed on the epithelial cells of the hair follicle or sebaceous gland which found on and around the face. The host body immune system is responsible for controlling the population of parasites and Disruption of the cutaneous barrier causes stimulation of Toll-like receptors (TLRs) Consequently, Demodex chitin detect by keratinocyte TLRs. According to the results, association between Demodicosis and the HLA gene showed that individuals with the gene HLACW2 are five times more likely to develop Demodicosis than others because Nk2 and T1 cells of the adaptive immune response are reduced. In human Demodicosis, factors such as carbohydrate-like Tn antigen (expressed by Demodex) and secretion of pro-inflammatory mediators may play a role in the innate immune response. Additionally, the expression level of TLR2 was increased and TLR4, TLR6 expression was decreased. Flow cytometry analysis of blood samples collected from individuals with human Demodicosis and healthy individuals showed that in the patient group, there were more T9 and T reg cells in the blood samples and in skin homing T cell populations compared to the control group. Studies of canine Demodicosis have reported that lymphocyte populations are composed mostly of CD3+ and CD8+ T cells. The importance of the humoral immune response during primary Demodicosis has not yet been determined because no significant differences in circulatory immune were seen. It seems that the host immune system appears to recognize and tolerate the presence of these mites, although the physiological role of human Demodex mites in healthy skin remains unclear, especially the way in which they escape the innate immune system is very important.