Understanding, navigating complex immunological routes

May 01, 2007, 4:00am

Understanding the basic concepts of cutaneous immunology, and specifically, the immunology of psoriasis, is vital to successfully embracing newer biologic therapies.

Key Points

National report - To understand the biologics' function, it is important to understand immunology first.

This understanding will help physicians choose the appropriate biologics and allow them to customize and personalize treatments for psoriasis patients.

"Contemporary cutaneous immunology is an ongoing process, and every month there is a new discovery that may alter what you already know. Researchers are constantly discovering and rediscovering new functions of T cells and how the biologics may work in other ways than we first anticipated," says Francis W. Iacobellis, M.D., a dermatologist in private practice in New York.

Dr. Iacobellis says it was previously believed that psoriasis was not an autoimmune or immunologic disease.

It was considered a genetic disease involving malfunctioning cells in the skin. These cells acted and grew faster than they should have. Now, research has evolved from these older views, and experts have found that an immunologic component plays a crucial role in psoriasis.

"There is a possibility that, in utero, when these T cells are developing, 95 percent of them are destroyed in the thymus because they either recognize self too well or they do not recognize self at all and attack everything. Some of these cells that should have been destroyed in the thymus were allowed to exist. Later on in life, then, they can be inappropriately or more easily stimulated to cause psoriasis," Dr. Iacobellis tells Dermatology Times.

MANY ROUTES TO SAME END

Current concepts about psoriasis suggest that it is genetic and immunologic.

According to Dr. Iacobellis, there is more to psoriasis than just cells that have gone awry. There are approximately 50 points along the way where there could be a mechanism paving the way for psoriasis, and the development of psoriasis is not just due to one single pathway.

"What researchers are discovering now is that there are alternate routes involved in the development of psoriasis. That is why some of the biologics only work some of the time, because they will pinpoint only one step in the immune cascade. However, the patient receiving a given biologic might have a different genetic background and may be stimulated for psoriasis in another biologic method," Dr. Iacobellis says.

According to Dr. Iacobellis, this is why no one biologic works on all patients suffering from psoriasis. The cause of psoriasis is multifactorial and there exists a mosaic of genetic backgrounds for humans.

"If you do not know the immunology, you cannot possibly get a feel for how these drugs are working and even when to effectively implement them. If physicians better understand how they work, then they can intelligently pick and choose among them, and can move with purpose from one biologic to the next," Dr. Iacobellis says.