Quadruple-cytokine ELISPOT assays?

So they've got quadruple-cytokine ELISPOT assays now? I never heard of such a thing. Double-cytokine assays are well known, though not exceedingly common. But a quadruple-color ELISPOT assay? Analyzing those things must be a real challenge, especially when it comes to disambiguating the mixed-color spots.