Re: I got the blood tests!
Actually, it is known as Th0, Th1, and Th2.
"Stimulation of Th1 cells tends to lead toward "normal" immune reactions, while stimulation of Th2 cells tends to lead toward allergy/asthma type reactions. There are a number of interleukins involved.
One of the current theories to explain increasing autoimmune and allergy disorders is called the "hygiene hypothesis". Basically, the hypothesis is that us modern citizens are too clean, which leads it to attack normal tissue."
http://en.wikipedia.org/wiki/Hygiene_hypothesis
"Lack of early childhood exposure to infectious agents, symbiotic microorganisms (e.g., gut flora or probiotics), and
parasites increases susceptibility to allergic diseases by suppressing natural development of the immune system. It is hypothesized that the TH1 polarized response is not induced early in life leaving the body more susceptible to developing TH2 induced disease."