Skin reactivity to aeroallergens is reduced in human T‐lymphotropic virus type I‐infected healthy blood‐donors (asymptomatic carriers)

Abstract

The HTLV-I infection reduces the frequency of respiratory allergy and skin reactivity to aeroallergens.

Clinical and immunological features of patients with atopy and concomitant HTLV-1 infection

“…Although we cannot rule out the possibility that the exacerbated Th1 immune response observed in HTLV-1 infection contributed to the decreased prevalence of atopy determined by the SPT, it is possible that other factors might be involved in reducing the skin test response to aeroallergens in HTLV-1-infected subjects. For instance, the response to the prick test with histamine, used as a positive control, was lower among HTLV-1 carriers (17). Interestingly, other investigators have also found that the test for delayed type hypersensitivity to antigens, a reaction associated with a type 1 immune response, also shows a decreased response by HTLV-1-infected subjects.…”

“…We have previously published a case report regarding a patient who had severe asthma and HTLV-1 infection, but we later showed that the prevalence of atopy based on the positivity of SPT and clinical manifestations was lower in HTLV-1-infected subjects compared to uninfected controls (17,18). Although we cannot rule out the possibility that the exacerbated Th1 immune response observed in HTLV-1 infection contributed to the decreased prevalence of atopy determined by the SPT, it is possible that other factors might be involved in reducing the skin test response to aeroallergens in HTLV-1-infected subjects.…”

“…Additionally, all sera were negative for HIV, syphilis, hepatitis B, and hepatitis C. A complete neurological exam was performed to determine the presence of mild manifestations of HTLV-1-related myelopathy and the Expanded Disability Status Scale (EDSS) was applied. A survey to evaluate the prevalence of atopy in a sample of asymptomatic HTLV-1 carriers admitted to the clinic was performed previously using a directed questionnaire on the basis of the International Study of Asthma and Allergies in Childhood (ISAAC) (19), and clinical examination (17). Based on this survey, 15 patients with atopy and 15 controls paired for age were selected to participate in the present study.…”

“…The SPT was performed using a panel with nine relevant local allergens: D. pteronyssinus, D. farinae, Blomia tropicalis, Aspergillus fumigatus, Cladosporum herbarum, Periplaneta americana, Blattella germanica, and dog and cat epithelia (Alk Abello, Denmark), according to a standardized technique (17). Histamine (1:1000) and saline were used as positive and negative controls, respectively.…”

“…We have shown previously that the prevalence of atopy and allergic diseases is lower in HTLV-1-infected subjects than in uninfected individuals (17), and that atopy and HTLV-1 infection may co-exist (18). The objective of the present study was to characterize the immune response in patients with HTLV-1 and concomitant atopy, and to determine whether HTLV-1 infection influences the immune response to Dermatophagoides pteronyssinus (Derp) antigen, the most common aeroallergen among atopic patients in Brazil.…”