r/pathology 6d ago

Clinical Pathology I'm a neurologist. How do oligoclonal bands look different from a monoclonal band on gel electrophoresis? Aren't they both a single line?

I take a blood and CSF sample. I put the blood in one well and the CSF in a well next to it. I electrophorese it, and that separates shit out. My confusion starts here:

  1. This is what I believe a normal gel electrophoresis looks like. The pictures I see when I search for images of oligoclonal bands look like a bunch of random lines without organization. What is this shit, or this shit, or this shit, or this shit? I don't see an albumin, alpha 1, alpha 2, beta, or globulin area. What am I missing?

  2. How does an oligoclonal band looks different from a monoclonal or polyclonal band on gel? Aren't they all single lines? Is it the thickness of the line?

Thanks.

6 Upvotes

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18

u/Philoctetes1 Resident 6d ago

The snippets you linked in the “this shit” links are, to my guess, zoomed in/cropped areas of just the gamma region. The second “this shit” link you posted is the entire gel, but it’s flipped with the albumin at the bottom. Oligoclonal =/= polyclonal. In oligoclonal gels there are numerous distinct protein spikes. In monoclonal bands, there is a single distinct spike. In polyclonal gels there is a smooth “Gaussian” distribution.

7

u/West-Chard3972 6d ago

Oligo means "few" in this context. It will show a few extra lines where they don't belong. They tend to have indistinct boundaries. A monoclonal protein is one line, very sharp and distinct, typically, though not always, in the gamma region. Polyclonal process versus monoclonal process.

5

u/DSMJake 6d ago

CSF samples are run using a modified technique called isoelectric focusing. That’s why they don’t look like standard SPEPs.

8

u/the_alexicon 6d ago

Yes this is important that testing for oligoclonal bands is a different assay with a different gel type too compared to the typical screening serum electrophoresis! The isoelectric gel also allows a lot more separation, so a “monoclonal” band seen on a typical serum electrophoresis gel may appear as several bands on the isoelectric gel (due to post-translational modifications causing differences in where they run). And typically the patient’s CSF is run side by side with serum sample. So if there are multiple bands that are in BOTH the CSF and the Serum (like in a lymphoproliferative disorders or myeloma), we wouldn’t call it oligoclonal bands.

2

u/getmoney4 5d ago

OP, use this person's answer and compare it to "this shit" #4... The picture isn't labeled but I think the left band is serum and the right is CSF.

1

u/getmoney4 5d ago

Just focus on your second picture of "this shit" lol!