Many years ago, Professor Alan Ebringer of Kings College London discovered that a certain immunoglobulin--IgA-Kp--was responsible for AS, or rather the active agent provocateur
. Some AS patients develop a secondary condition due to the proliferation of immunoglobulin: Berger's disease in particular but also other forms of what might be termed "amyloidosis."
The current methods used in measuring serum Ig (IgM, IgA, plus IgG) cannot yet identify the reason
these immune components proliferated. A more accurate test would show that these are highly increased within our lymph, produced in response to the presence of the Klebsiella pneumoniae
(-Kp) bacterium in our gut (microbiome). This bacterium blooms (population explosion) in the presence of dietary starch.
In this paper (.pdf)
figure 1 shows a scatter plot of serum Ig in a large group of patients with active AS, Crohn's, and UC versus control groups.