Current status of mold immunotherapy

There is evidence to suggest that molds can cause IgE-mediated upper respiratory tract disorders and immunotherapy is efficacious in a select group. The environmental sampling studies show a remarkably small numbers of molds accounting for a majority of the mold load in various diverse locations. These are Cladosporium, Basidiospores, Aspergillus, and Alternaria-Penicillin families. Basidiospores have been underreported in the older studies because of difficulties in their identification. Whether the absolute mold level is the most important factor leading to IgE formation and induction of upper respiratory tract symptoms is uncertain. Certainly, the majority of the studies are based on the assumption that the absolute level of mold in the environment is the most important factor leading to the development of symptoms, but this is not based on strong evidence. A major problem in the majority of the studies is a lack of standardization of extracts which may lead to false negatives on skin testing and thus produce variable data in population evaluations comparing the prevalence of mold to its ability to induce IgE production and symptoms. The best current trials to document the efficacy of mold immunotherapy have been with the standardized Cladosporium extract. Unfortunately, these results cannot be extrapolated to the commercially available mold extracts available in the United States either for immunotherapy or for skin testing. These extracts are highly variable in their potency, prone to high false negative rates, and at best serve as poor skin testing reagents and possibly even worse immunotherapy reagents. Adequately standardized mold reagents are urgently needed to determine whether the Cladosporium data can be extrapolated to them in any meaningful way.