two quick path questions

[MudPhud20XX]

1. In multiple myeloma, why would you get an increase risk of infection?

2. One of the questions I did had target cells shown in sickle cell anemia. Is it possible? So how do you explain that?

Many thanks in advance.

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[Paddles]

People with sickle-cell become asplenic very early on (local conditions in the spleen promote cell aggregation and infarction) so the target cells are a result of this asplenia rather than the HbS itself, I think.

Myeloma is an immunosuppressed state but not sure about the mechanism / details, sorry.

 

[Apoplexy__]

Pathoma explains the immunosuppression in MM really well. I seem to recall it's a double-whammy of the neoplastic plasma cells making faulty Ig's, along with overcrowding functional immune cells and stealing their resources.

Target cells are really nonspecific. The only thing you need to know about them is that if you see them with microcytic anemia + normal Fe levels, it tips you off to thalassemia.

 

[SBR249]

In multiple myeloma, you have clonal expansion of plasma cells that make just one specific Ig with one specificity and those neoplastic cells crowd out other cells in the bone marrow including other immune cells and also other long-lived plasma cells. What that leads to is 1) a lack of diversity in your Ig repertoire as all your plasma cells are the neoplastic clone producing just one specific Ig (seen as an M-spike) and 2) you are now lacking in other immune cells that are normally produced in the bone marrow like the granulocytes and lymphocytes

All this adds up to a severely immunosuppressed state because the neoplastic cells basically take over and thus you are prone to infections because your innate immune system lacks cells and your humoral immunity system lacks the diversity of antibodies to fight off different pathogens.

As a side-note: the mechanism behind the M-spike is you get whopping amounts of one specific protein (the Ig) whereas normally your antibodies would be all different and thus you see one narrow spike versus the normal flat distribution in molecular weight of plasma proteins (not counting the albumin peak).