Resposta anticórpica de IgE, IgG1 e IgG4 a Blomia Tropicalis em pacientes atópicos

Abstract

Sensitization to indoor allergens is the most important risk factor associated with asthma. In tropical countries, Dermatophagoides pteronyssinus (Dp) and Blomia tropicalis (Bt) are considered as clinically relevant house dust mites (HDMs). This study aimed to evaluate the IgE, IgG1, and IgG4 reactivity to Bt among Brazilian atopic patients. One hundred-ten patients presenting asthma and/or rhinitis (AR) and 33 control subjects were submitted to skin prick test (SPT) with HDM extracts and venipuncture for ELISA and Immunoblotting. The majority (56.4%) of AR patients had positive SPT to Bt extract (group Bt+), although 50.9% were reactive to both mites (Bt and Dp) and 5.5% were sensitized to Bt only. IgE- ELISA detected 39.1% positivity with significantly higher IgE levels in the group Bt+ than the Bt- and control groups. Levels of IgG] were significantly higher in both Bt+ and Bt- groups than the control group. IgG4 showed significant difference between both Bt+ and Bt- groups and a positive correlation with specific IgE. The major allergenic components recognized by sera of Bt+ AR patients were the 54 , 68, and 66 kDa proteins. Our Bt+ AR patients seem to, be more frequently sensitized to high molecular weight (HMW) components than to the low molecular weight ( 11-15 kDa) allergens predominantly detected in other studies. IgG4- binding proteins closely resembled the IgE allergenic profile while IgG1-binding proteins, particularly the HMWs, were widely recognized by sera of all three groups, suggesting that these HMW antigenic components could be evaluated as potential candidate antigens for allergen exposure, sensitization, and immunotherapy studies.