The Role of HLA A2 and Cw2 in the Pathogenesis of Human Demodicosis

Abstract

Background: Demodicosis is a chronic skin disease caused by parasitic mites of the genus Demodex. It usually affects the face area causing major esthetical problems. The pathogenesis of demodicosis is not fully understood; however, it is quite apparent that immunological mechanisms mediate its development. Objective: The goal of this study was to study the correlation between immunological and immunogenetic data obtained from patients with demodicosis in order to clarify the pathogenesis of Demodex infestation. Methods: Twenty-five patients with demodicosis and 13 age- and sex-matched healthy subjects participated in the study. The presence of mites was determined by microscopic inspection of sebum gland secretions. The immune response was evaluated by identifying membrane markers of different immune cells using monoclonal antibodies (anti-CD3+, CD4+, CD8+, CD16+, CD20+ and CD95+) while the concentration of IgA, IgM and IgG was measured by simple radial immunodiffusion. The level of circulating immune complexes and total hemolytic complement as well as the preparatory and digestive function of neutrophils and the functional activity of leukocytes were also studied. Patients were typed for HLA A, B, Bw and Cw using the microlymphocytotoxicity method. Results: The comparison between patients with and without the A2 phenotype showed that the latter have lower numbers of CD8+, lower functional activity of leukocytes, higher concentrations of IgA, larger affected skin areas and are more often affected by deep papular and papulopustular forms of demodicosis than those with the A2 phenotype, showing that this allele has a protective role in demodicosis. Patients exhibiting the Cw2 phenotypes were rather susceptible to demodicosis. They showed decreased numbers of CD3+, increased levels of phagocytic activity, higher mite density and severer skin damage as compared to patients lacking Cw2. Conclusions: The HLA A2 and Cw2 phenotypes have an important diagnostic, prognostic and pathogenetic significance and could play a role in resistance or susceptibility to demodicosis by regulating the end phase of the immune response.

Retrospective Analysis of the Association Between Demodex Infestation and Rosacea

“…60 Based on the present research regarding Demodex species infestation and the occurrence of rosacea, we think that there are 4 issues to be studied in the future. The mechanical stimulation of the mites' movement could cause damage to hair follicles and sebaceous glands and trichangiectasis, resulting in rosacea.…”

The effect of blood glucose regulation on the presence of opportunisticDemodex folliculorummites in patients with type 2 diabetes mellitus

“…13 An increased incidence of Demodex mites was found in subjects with human leucocyte antigen (HLA)-Cw2 and HLA-Cw4 alleles, which was related to a decrease in natural killer cells. 21 Immunosuppression may result in an increase in the mite numbers, favouring an inflammatory reaction, or it may cause an impaired immunological response in the skin to the mite infestation. Data regarding the prevalence of Demodex mite infestations in patients with diabetes are rare.…”

Sociodemographic characteristics and risk factor analysis of Demodex infestation (Acari: Demodicidae)

“…Therefore, Demodex mite count as a sufficient aetiological condition for facial dermatosis needs to be investigated further. Mumcuoglu and Akilov (2005) reported an increased incidence of demodicidosis in patients with human leucocyte antigen (HLA) Cw2 and Cw4 alleles related to a decrease in natural killer cells. It is thus evident that HLA could play a role in resistance or susceptibility to demodicosis by regulating the end phase of the immune response.…”