Cytokine | Principal component 1 | Principal component 2 |
|---|
IFN-γ |
0.583
| 0.270 |
IL-4 |
0.888
| -0.054 |
IL-5 |
0.912
| 0.072 |
IL-10 | -0.046 |
0.968
|
- The principal components were extracted by the factor analysis of cytokine responses. Strong loadings (> 0.5) are indicated in bold. This procedure involves a mathematical procedure that transforms a number of correlated variables into a smaller number of uncorrelated variables called principal components. The first principal component accounts for as much of the variability in the data as possible, and each succeeding component accounts for as much of the remaining variability as possible [42]. This procedure is valuable for this immunology data because it allows the simultaneous effects of all the cytokines to be studied at the same time which is a better reflection of the biological situation that the standard procedure of studying correlations between individual cytokines and infection intensity [43]. The two principal components were then used to determine the cumulative effects of the cytokine responses on infection status by logistic regression.
