Immunological Basis for IgE Hyper-Production in Enfuvirtide-Treated HIV- Positive Patients

Effect of sublingual immunotherapy with grass monomeric allergoid on allergen-specific T-cell proliferation and interleukin 10 production

BACKGROUND

Sublingual immunotherapy (SLIT) is safe and efficacious in the treatment of patients with allergic rhinitis. Although favorable clinical effects have been observed with controlled trials as early as a few months since the beginning of treatment, few biological changes induced by SLIT have been demonstrated.

OBJECTIVE

To investigate in grass-allergic patients the effect of a 2-month SLIT regimen, administered with a simplified protocol without up-dosing, on proliferation and production of cytokines characteristic of the regulatory T-cell phenotype (interleukin 10 [IL-10] and transforming growth factor beta [TGF-beta]) by allergen-specific T cells.

METHODS

Patients were recruited to the study in January 2006. SLIT was performed by self-administration and was continued for 60 days from February to April 2006. Eleven grass pollen-allergic patients with seasonal rhinitis were treated daily before the pollen season for 2 months with a modified allergen (monomeric allergoid) derived from a 3-grass pollen extract. Allergen-specific proliferation and production of IL-10 and TGF-beta were measured on peripheral blood mononuclear cells at baseline and treatment end. Tetanus toxoid served as the control antigen.

RESULTS

After SLIT, allergen-specific (P = .002) but not tetanus toxoid-specific proliferation decreased, whereas IL-10 transcription increased (P < .001). TGB-beta transcription was also increased after treatment, although not statistically significantly (P = .06). Changes in proliferation to allergen and in IL-10 transcription were correlated (r = -0.82, P = .003).

CONCLUSIONS

A short-term course of SLIT with modified allergen in grass-allergic patients is associated with the reduction of allergen-specific proliferation and with the up-regulation of the IL-10 regulatory cytokine.

HIV-1 gp41 heptad repeat 2 (HR2) possesses an amino acid domain that resembles the allergen domain in Aspergillus fumigatus Asp f1 protein: review, hypothesis and implications

Enfuvirtide (ENF, T-20, Fuzeon) is the first synthetic peptide to be modeled according to the amino acid sequence of HIV-1 heptad repeat 2, which was used to treat cohorts of HIV-1-infected individuals who had failed to respond to treatment with the anti-HIV-1 cocktail HAART. It was reported that when injected subcutaneously, Enfuvirtide reduced viral RNA in patients' blood by 1.96 log(10), leading to a subsequent increase in the number of CD4(+) T cells in the blood. The drug treatment caused adverse effects at the injection site in a small number of treated individuals, and a gradual increase in IgE in the blood during prolonged treatment. Enfuvirtide was approved for treatment of HIV-1 patients who developed resistance to HAART. The present review attempts to explain the adverse effects of Enfuvirtide at the skin site of injection, and the gradual increase in IgE in patients' blood during treatment. These phenomena were reported to resemble the effect of allergens that cause asthma in humans. It is hypothesized that since the amino acid domain of the Asp f1 allergen from Aspergillus fumigatus was identified in the N-terminus of an 18 kDa protein, it may be useful to compare Asp f1 peptide aa 7-22 from the beta-hairpin sequence to the beta-hairpin sequence of the heptad repeat 2 of HIV-1 gp41. The comparison revealed that the amino acid sequence resembles part of the Asp f1 aa 7-22 allergenic domain. The heptad repeat 1 of gp41 also resembles the fungal allergen. It is suggested that the Enfuvirtide peptide be tested experimentally to determine if ENF peptide is capable of binding to IgE antibodies from Enfuvirtide-treated, HIV-1-infected patients, and whether the HR2-derived peptide is capable of inducing basophils that were isolated from healthy individuals and from ENF-treated and untreated HIV-1 patients to release histamine and IL-4.