New Treatments: Helminth Therapy

Hookworm

In November of 2010, a study was conducted by researchers Endara, Vaca, Chico, Erazo, Oviedo, Quinzo, Rodriguez, Lovato, Moncayo, Barreto, Rodrigues and Cooper from the Colegio de Ciencias de la Salud at the Universidad San Francisco de Quito and published in the Journal of the British Society for Allergy & Clinical Immunology. The study focused on the effect of anti-helminth treatments on the prevalence of allergies. Helminths are parasitic worms that need the resources of a host body to survive. Researchers have been experimenting with helminth therapy or the intentional inoculation of patients with helminths, for quite some time now. The theory behind helminth therapy is that our body's immune system is naturally regulated by the presence of these helminths. As part of their survival, these parasites down-regulate the part of the host's immune system that is also responsible for the auto-immune and allergic responses. However, modern society has become so "clean" that many of these parasites can no longer survive. Some theorize that the lack of natural parasites has screwed up the immune system, resulting in an increased incidence of auto-immune diseases and allergies.

Obviously there are many helminths that are so dangerous that their presence would threaten our health, but some are relatively safe. For example, low concentrations of hookworms and whipworms are not considered a real health hazard. Therefore, these "weaker" helminths have been experimented with in helminth therapy. By introducing hookworms or whipworms into patients with auto-immune diseases and severe allergies, the immune system may work itself out. In the case of allergies, this means that the body will no longer respond to an allergen. For example, the binding of pollen to the IgE antibody will no longer activate the mast cells and induce the release of histamine and other mediators. In other words, the body becomes desensitized to the allergen.

Whipworm

In the study, researchers performed an allergen skin test on school-aged children from two different communities, to determine their reactivity to the allergen. The children of one community received the anti-helminth treatment, ivermectin, for fifteen to seventeen years, while the children of the other community did not. The researchers found that twice as many children receiving ivermectin experienced an allergic response to the skin test (16.7%), compared to the children who hadn't received anti-helminth therapy (8.7%). For children treated with ivermectin, the results show a statistically significant increase in the number of those with allergies. However, it is unclear whether other factors were accounted for. For example, the incidence of second-hand smoke or pollution may have been greater in the community giving ivermectin treatments, which may have accounted for the increased incidence of allergies in the population. Either way, helminth therapy will definitely prove to be very controversial.  

Where do we drawn the line? Helminth therapy may reduce the severity of auto-immune diseases and allergic reactions, but is the danger associated with helminth therapy worth the risk? More research needs to be done, especially on the long-term risk of using this treatment. However, if helminth therapy does prove to be effective and safe in the long run, are people really going to be willing to infect themselves with a parasite? Only time will tell whether helminth therapy will become the new treatment or fade from view.

For more information about Helminth Therapy Click Here

For a more in-depth look at using parasites, take a look at the blog Waiting For The Cure, which chronicles one person's use of parasitic worms to treat Crohn's Disease

To view a Live Science article about Helminth Therapy Click Here

New Treatments: Targeting Neuropeptides

NPY

In January of 2011, a study was conducted by researchers Sacchetti, Micera, Lambiase, Speranza, Mantelli, Petrachi and Bonini from the Department of Ophthalmology at the University of Rome and published in Molecular Vision. The study focused on the role of neuropeptides in the inflammatory response associated with allergic conjunctivitis. Neuropeptides are molecules that work with mediators to increase or decrease their effects. For example, when the neuropeptide NPY is released in conjunction with norepinephrine, it amplifies the vasoconstriction or squeezing of blood vessels produced by norepinephrine. In the case of allergies, neuropeptides may play a role in increasing the effects of mediators used in the inflammatory response. For example, neuropeptides may be released along with histamine, producing an increased inflammatory response that would not be seen if histamine were released by itself.

In the study, researchers sought to measure levels of neuropeptides in the tears of patients with allergic conjunctivitis and those without. If there were more neuropeptides in the tears of allergic conjunctivitis patients, it is likely that neuropeptides play a role in the inflammatory response. A conjunctival provocation test (CPT) was used to measure the allergic response of fifteen patients with allergic conjunctivitis and ten patients without allergic conjunctivitis. This served as a control because the patients with no allergic response should have a very low CPT score. Then tear samples were collected from all patients and the amount of neuropeptides VIP, NPY, CGRP and SP were measured.

The researchers found that the concentration of VIP, CGRP and SP neuropeptides were higher in the tears of allergic conjunctivitis patients. However, there was no significant difference in the number of NPY neuropeptides in the allergic conjunctivitis and non-allergic patients. However, this evidence suggests that neuropeptides may play a role in increasing the effects of mediators involved in the inflammatory response. More research needs to be done to identify that role. If researchers succeed, this opens up another avenue for treatment. For example, inhibiting the binding of neuropeptides or blocking their release, can decrease the effects of neuropeptides and maybe decrease the effects of inflammatory mediators like histamine. It will be interesting to see how this area of research develops in the future.

If you are looking for a new way to approach allergic conjunctivitis, discuss recent developments in neuropeptide research with your healthcare provider. 

New Treatments: Alcaftadine vs. Olopatadine

In February of 2011, a study was conducted by researchers Ono and Jane from the Dobbs Ocular Immunology Laboratories of Emory University School of Medicine & Emory Eye Center and published in Drug Design, Development & Therapy. The study focused on the role of conjunctival tight junctions in the allergen-induced inflammatory response. The tight junctions of the conjunctiva epithelium serve as a barrier to prevent the allergen from entering the conjunctiva and eliciting an immune response. If you remember, the epithelium is similar to a liner, keeping unfavorable things out of the conjunctiva. In people with seasonal allergies, they seem to express a lower level of proteins used to create these tight junctions; less tight junctions results in more allergens breaking through. Also, many allergens have enzymes that can be used to force entry into the conjunctiva.

Enzymes are a type of protein with many different functions. The function of the enzyme depends on what type it is; there are thousands of enzyme types that have been identified. In the case of allergens, they contain a type of enzyme that can breakdown the tight junctions in the epithelium, allowing the allergen to pass through. For example, enzymes from pollen and house dust mite feces have been shown to degrade the junctions, making the conjunctiva more permeable to the allergen. If you remember, once the allergen enters the conjunctiva, it binds to the IgE antibody on the mast cells, stimulating the release of histamine and other mediators to elicit the allergic reaction.

In the study, researchers compared the effect medications alcaftadine and olopatadine on the conjunctival tight junctions. Eighty mice were used in the study. They were broken up into five groups, consisting of sixteen mice each. Each of the five groups were subjected to a different portion of the study. Overall, the goal was to determine which medication, alcaftadine or olopatadine, had a greater efficacy.

The results showed alcaftadine to have a greater anti-histamine effect than olopatadine. More importantly, alcaftadine had a protective effect on the tight junction. Alcaftadine seemed to prevent allergen-initiated breakdown of the tight junctions, decreasing the number of allergen molecules that passed through the conjunctiva. Although the actual mechanism of action is unknown,  the ability of a drug to affect the tight junctions opens up a new avenue of research for allergic conjunctivitis therapy. 

For more information about alcaftadine (Lastacaft) Click Here

For more information about olopatadine (Patanol) Click Here