Pattern Recognition Techniques - Biomedical Signal Analysis: Contemporary Methods and Applications - page 201

vised perceptron learning after principal component analysis for dimen-
sion reduction turned out to be highly successful by linearly separating
the patients into two groups with different diagnoses. The simplicity of
the perceptron made it easy to extract diagnosis rules, which partly were
known already and could now readily be tested on larger data sets.
The neural network signal analysis of this immunological data set
has been performed in [257] and extended using ICA in [256].
Medical background
Immunological approaches have gained increasing importance in modern
biochemical research. Within the last few years a broad array of sophis-
ticated experimental tools has been developed, and ultimately has led to
the generation of an immense quantity of new and complex information.
Since the interpretation of these results is often not trivial, there is a
need for novel data analysis instruments that allow evaluation of large
databases. For this purpose three different algorithms were applied to
immunological data that were generated as outlined below.
In inflammatory airway diseases, lymphocytes accumulate in the pul-
monary tissue. Since the lung is perfused by two different arterial sys-
tems that feed the bronchi and the alveoli, lymphocytes can enter the
pulmonary tissue by two separate vascular routes. Therefore, a selective
recruitment of distinct effector T cells into the two pulmonary compart-
ments may occur. Controlled tracking of T cells to peripheral sites oc-
curs through adhesion molecules and the interaction of chemokines with
their counterpart receptors. Accordingly, a number of chemokine recep-
tors are differentially expressed on lymphocytes in an organ- or disease-
specific manner [92]. Chemokines are classified into four families (CC,
CXC, CX3, C) based on the positioning of amino acids between the two
N-terminal cysteine residues (see also [224]). CX3- and C-chemokines
are each represented by single members, whereas the other two groups
have multiple members. While the group of CXC-chemokines acts pref-
erentially on neutrophils, the CC-chemokine group is mainly involved in
the attraction of lymphocytes [224]. However, these distinctions are not
absolute.
To test whether a selective recruitment of T cells into the lung oc-
curs, 37 children suffering from various pulmonary diseases were selected
for the study. Based on clinical and radiological findings, the children
were further subdivided into two groups which mirrored the two pul-