**Introduction to cellular polyfunctionality.**
Cellular polyfunctionality refers to the capacity of a single cell to express multiple effector molecules simultaneously. This type of single-cell measures have become accessible with recent technical advances in flow cytometry, sequencing and chip-based assays.

The data are highly multiparametric in nature, but for effector molecules, which can be interpreted in a binary manner (cells being positive or negative for the given effector molecule) so-called boolean combination gating can mathematically create all possible combinations of a set of effector molecules (2

^{n} combinations). From these boolean data one can mathematically regenerate any given combination of effector molecules and one can apply sophistical mathematical algorithms that will take into account all different combination subsets, such as the Polyfunctionality Index (Larsen

*et al.* PLoS One 2012).

I have developed a free software (

www.FunkyCells.com), which allows a simple assessment of all combinations of effector molecules. The software will also allow to calculate the poyfunctionality index.

This topic is dedicated to the discussion of polyfunctionality in general. Discussion about my software is available on my company website (

www.FunkyCells.com).