Development of cockroach immunotherapy by the Inner-City Asthma Consortium

Abstract

Background Cockroach allergy is a key contributor to asthma morbidity in children living in urban environments. Objective We sought to document immune responses to cockroach allergen and provide direction for the development of immunotherapy for cockroach allergy. Methods Four pilot studies were conducted: (1) an open-label study to assess the safety of cockroach sublingual immunotherapy (SLIT) in adults and children; (2) a randomized, double-blind biomarker study of cockroach SLIT versus placebo in adults; (3) a randomized, double-blind biomarker study of 2 doses of cockroach SLIT versus placebo in children; and (4) an open-label safety and biomarker study of cockroach subcutaneous immunotherapy (SCIT) in adults. Results The adult SLIT trial (n = 54; age, 18–54 years) found a significantly greater increase in cockroach-specific IgE levels between the active and placebo groups (geometric mean ratio, 1.92; P < .0001) and a trend toward increased cockroach-specific IgG4 levels in actively treated subjects (P = .09) but no evidence of functional blocking antibody response. The pediatric SLIT trial (n = 99; age, 5–17 years) found significant differences in IgE, IgG, and IgG4 responses between both active groups and the placebo group but no consistent differences between the high- and low-dose groups. In the SCIT study the treatment resulted in significant changes from baseline in cockroach IgE, IgG4, and blocking antibody levels. The safety profile of cockroach immunotherapy was reassuring in all studies. Conclusions The administration of cockroach allergen by means of SCIT is immunologically more active than SLIT, especially with regard to IgG4 levels and blocking antibody responses. No safety concerns were raised in any age group. These pilot studies suggest that immunotherapy with cockroach allergen is more likely to be effective with SCIT.

New Insights into Cockroach Allergens

“…Wood et al summarized the results of four pilot clinical trials using sublingual immunotherapy (SLIT) and subcutaneous immunotherapy (SCIT) with German cockroach extract to treat cockroach allergic adults and children ●●[121] (Table 2). Both modalities of cockroach immunotherapy were safe, with no severe reactions seen that could bring concerns of continuation of research on cockroach immunotherapy.…”

Cockroach allergen exposure and risk of asthma

“…These cockroaches include American cockroach ( Periplaneta americana ), German cockroach ( Blattella germanica ), oriental cockroach ( Blatta orientalis ), brown-banded cockroach ( Supella longipalpa ) and smoky brown cockroach ( Periplaneta fulliginosa ). In particular, both German and American cockroaches are the predominant species that infest human dwellings (23). Predominant sources of environment cockroach allergens include cockroach saliva, fecal matter, spermatophore, shredded skin, and desiccated remains of the insect.…”

Indoor Allergens and Allergic Respiratory Disease

“…However, there is a lack of consensus on basic treatment parameters (i.e., dose and duration) and a need for rigorous, long-term, double-blind, placebo-controlled randomized clinical trials for house dust mite allergies [112]. Four pilot studies of cockroach immunotherapy suggest that immunotherapy with cockroach allergen is more likely to be effective with SCIT than SLIT [113]. …”