The Quantification of IgG Specific to α-Gal Could Be Used as a Risk Marker for Suffering Mammalian Meat Allergy

The alpha-Gal Syndrome is a delayed meat allergy characterized by the presence of sIgE against α-Gal epitope. It is known that the α-Gal present in tick saliva induces the sensitization to this epitope ending in the production of sIgG and sIgE to α-Gal. It could be considered that the more times a person is bitten by tick species, the higher the probability of making the switch from sIgG to sIgE to α-Gal and developing allergy, but it is no clear when the switch occurs. To determine the likelihood that a subject bitten by ticks but without AGS be at risk of developing this allergy, we quantified the levels of sIgG to α-Gal by an automated system (ImmunoCap). To stablish a cut-off value for sIgG to α-Gal, a receiving operating curve (ROC) was constructed. The statistical analysis demonstrated that the risk of suffering AGS in individuals bitten by ticks was 35% when the sIgG to α-Gal was greater than or equal to 40 µg/mL. Our data indicate that the sIgG values against α-Gal could be used as a prognostic marker for developing mammalian meat allergy.

Selective IgA Deficiency a Probable Risk of Recurrent Chest Infections in Asthmatics

BACKGROUND

Selective immunoglobulin A (IgA) deficiency is characterized by a high incidence of both recurrent infections and atopic diseases. Asthma is one of the most common lung diseases affecting around 300 million people worldwide and is associated with risk of serious pneumococcal disease and microbial infections. Multiple studies have attributed this to impaired innate and adaptive immunity in asthmatics. An additional probable hypothesis is the existence of an underlying primary immunodeficiency (PID), such as selective IgA deficiency (sIgAD).

AIM

To assess the prevalence of selective IgA deficiency and its correlation to recurrent infections in asthmatic patients.

METHODS

A case-control study was conducted on 80 subjects who were divided into 3 groups: 20 Asthmatic patients with recurrent chest infections (Group A), 20 asthmatic patients without recurrent chest infections (Group B) and 40 healthy controls (Group C).

RESULTS

On comparing the 3 studied groups, there was a statistically significant difference between the three groups (p = ˂0.001) concerning serum IgA. The mean serum IgA was statistically significantly lower in Group A&B than in Group C. Furthermore, it was significantly lower in Group A than in Group B and C (p1,2 <0.002 and <0.001*, respectively). The percentage of selective IgA deficiency or partial IgA deficiency in asthmatic patients was 56% (26 patients). Group A showed a statistically significant higher percentage of selective/partial IgA deficiency.

Grass tablet sublingual immunotherapy downregulates the TH2 cytokine response followed by regulatory T-cell generation

BACKGROUND

Sublingual administration of Phleum pratense allergen immunotherapy (SLIT) tablets is a clinically efficient treatment for grass pollen-induced rhinoconjunctivitis. This immunotherapy downregulates TH2 immune responses, induces tolerogenic pathways, and increases regulatory T cells. However, associated immune response markers of allergen desensitization remain undefined.

OBJECTIVE

We sought to characterize the kinetics of individual changes in the immunologic response to grass tablet SLIT.

METHODS

We evaluated the systemic effects of SLIT in a longitudinal analysis of humoral and cellular immune parameters in peripheral blood samples.

RESULTS

Grass tablet SLIT administration induced a 2-phase systemic humoral and cellular response. The TH2 response was initially exacerbated and detected as increased allergen-specific IgE (sIgE) and IgG4 (sIgG4) levels and an increase in IL-4-producing cells, followed by downregulation of the TH2 response with a shift toward a TH1 cytokine profile. T cells with a regulatory phenotype were also elicited. Statistical correlations between immunologic measurements for each patient throughout therapy indicated that TH2 response downregulation and reduction of the immediate SLIT-induced IgE response were associated with increased allergen-specific IgG4 synthesis early in therapy. TH2 response downregulation by month 4 correlated with increased frequency of CD4(+) T cells with a regulatory phenotype by 12 months.

CONCLUSION

Changes in sIgE levels after therapy were linked to a specific IgG4 response, and production of blocking antibodies correlated with TH2 response downregulation. Reduced IL-4(+) cell frequency was linked to an increase in the frequency of CD4(+) T cells with a regulatory phenotype. Changes in sIgE levels and reduced IL-4 and blocking antibody levels could thus be used as indicators of a patient's immune response to therapy.