So... I just opened your image in ImageJ... and I'm worried about a few things:
Your image is a JPEG. Ideally - you should not be saving images as JPEGs - due to lossy compression - you can read more about that here. You should never use JPEG - especially for quantification analysis. It's better to use TIFF or the original file format of your imaging system.
If you zoom in on your image - you will see that the resolution of your dark spots is not high enough to measure reliably. Pixel-sized dark spots are abundant... so there is no way to say that they are real or noise or what? At least - I'd not consider this resolution reliable (perhaps others on the Forum here would disagree?) Have a look at the image below that I took of yours zoomed in. As it is almost impossible within this image to delineate your individual cells - I would doubt you could reliably measure your CXCL13 staining within.
All-in-all ... would it be possible to re-acquire these images at a higher resolution and saving as TIFFs??
I know this is perhaps not the answer you'd wanted... sorry for that. But it's the best way to get the best data you can.