Lupus can cause low WBC, RBC and platelet counts but the reason they are low is different with Lupus than in different diseases....

With lupus the body attacks the different types of blood cells, destroying them. There is usually evidence that the body is making enough cells but they’re being destroyed unlike with other diseases that inhibit the manufacturing of the cells, as is seen with bone marrow issues or vitamin deficiencies

An example of that evidence in the case of platelets: platelets will be low but the MPC will be higher than usual so doctors can see new platelets are being made but they’re being destroyed leading to low numbers

They can tell what’s happening with RBC as well. Thanks to a few different tests including RBC and Reticulocyte count doctors can see if the body is making enough supply and they’re being destroyed or if the body isn’t manufacturing them in high enough quantities

Has she ever have an ANA test done? a positive ANA would indicate whether or not an autoimmune disease is possibly the cause

Best of luck. I’m sure you’re terribly worried

Recently I finished 5 IV iron infusions. Low RBC s possibly may mean you're bleeding somewhere. It's also common with lupus and similar diseases.
Your wbc's help fight infection. A low count leaves you vulnerable to infection, where I high count can be a sign of infection.
Both need to be monitored carefully. A second opinion is an option

I stay anemic and must take iron supplements

Witch is good 4 lupus

My platelet count is217 normal white count 6.6 normal