Th1 & Th2 - Manipulating immune responses


Hi doctor Bob. Thanks for all your hard work in helping us who are infected/affected by HIV. Just have a quick question. It doesn't belong in this forum but didn't know who to ask and I can't find an active forum it would fit into Thought you'd be the most qualified... being an immunologist and all. I read an article that said that HIV infected people should look at supporting the Th1 immune response and suppressing the Th2 response. Just wanted to get your take on this. Besides getting treated properly by an HIV specialist, what else would you recommend? The article states to eat foods like shitake mushroom, foods high in plant sterols, fish oil, ginseng, plants from the raddish family and also recommends a range of vitamins, namely A, C, E, selineum an zinc. What are your thoughts. Also, since aquiring this virus I have had a killer sore and swollen throat, swollen nodes in the armpit, groin and just inside my elbows. They are fairly tender and have been up for months. Will they ever go down? I've only recently tested pos from a recent exposure. Is there anything u prescribe your patients for persistantly swollen nodes? Or are ARV's my only option? Any help you give will be most appreciated.



This topic can be very confusing for non-immunologists. Many physicians and even a large number of HIV specialists don't fully grasp the intricacies and complexities of the human immune response. Let me try to give you some basic background information about the Th1 and Th2 immune responses. There are two basic arms of the acquired immune response cellular and humoral. The cellular component includes the T-cells. There are different families of T cells that perform different and very specific functions. These various T-cells can be identified by "markers" on the cell's surface. The most famous are the CD4 "helper" T-cells, which serve both as coordinators (hence the name "helper") and participants in the immune response. CD8 T-cells are important partners and include cytotoxic T-lymphocytes (CTLs), which are also called "killer" T-cells. The primary role of CTLs is to eliminate cells from the body that are harboring infectious agents. CD4 plus CD8 T-cells make up over 80% of the body's total T-cell population. The normal ratio is two-to-one in favor of the CD4 T-cells. The remaining T-cells are gamma-delta T-cells. We still aren't sure what their specific function is!

T-cells "recognize" specific components (antigens) on invading germs (flu, HIV, etc.) using a "docking bay" type structure on their surface called a T-cell receptor (TCR). Antigens that dock snugly with the TCR trigger the T-cell to mount an immune response. Any given infection (flu, HIV, etc.) is usually recognized by several thousand T-cells. The very first encounter with a new infectious agent must be dealt with by rookie T-cells called "nave T-cells." The nave T-cells reproduce themselves and acquire the ability to perform key infection-fighting functions, such as cell killing and production of chemicals (cytokines) that help in the immune response). After the initial infection is controlled or eliminated, some of these highly skilled T-cells are retained as memory cells. Each and every infection we have been exposed to (measles, mumps, chicken pox, etc.) triggers the development of a team of long-lived memory T-cells whose job is to prevent the disease form recurring. Is everyone still awake and following this??? We're just getting to the more complicated stuff. New technologies now allow us to study these memory T-cell teams and they can now be subdivided even further. Each team has Th1 and Th2 subtypes. CD4 T-cells that make a cytokine called interferon-gamma, which works with CD8 T-cells (see above) to help them maintain their ability to kill infected cells in the body. These CD4 T-cells are termed "Th1 helper cells." Other CD4 T-cells produce different cytokines, such as interleukin 4 (IL-4) and work cooperatively with B-cells to assist and promote specific antibody production. These cells are called "Th2 helper cells."

Both CD4 and CD8 T-cells can make substances (chemokines) termed MIP-1 alpha, MIP-1 beta and RANTES. These chemokines can inhibit replication of some infectious organisms, including HIV. CD8 T-cells can kill infected cells by making specialized cell-destroying substances called granzymes and Perforin. See, I told you this got confusing. The reason this is all so important is that the balance between different functions (helpers, suppressors, CTLs, CD4s, CD8s, Th1, Th2, etc.) determines how well an infection is or is not controlled. Some immune-based therapies are designed to change the balance between responses boosting the number of Th1 vs. Th2 CD4 T-cells, for instance. However, things like shitake mushrooms, radishes and various foods, herbs, vitamins, minerals or trace elements do not affect this. Save the shitake mushrooms for a nice pasta sauce and toss the radishes into a healthy salad. A well-balanced diet is important for your overall good health, including immune health. However, trying to manipulate the immune response with items purchased at your local Piggly Wiggly or Vitamin Shoppe will not be helpful.

Regarding your lymphadenopathy, if it is indeed painful and persistent, it should be thoroughly evaluated by your HIV specialist. Treatment depends on the cause (HIV or something else going on).

Good luck! Things can (and will) get better. I promise.

Dr. Bob