Thanks for the follow-up.
Normal range of WBC count is 4×109 and 1.1×1010cells/L.
And a count lower than 3.5 ×109 cells/L is generally considered a low white blood cell count.
This level get decreased in viral infections, but also bacterial or parasitic infections.
Also level get decreased in vitamin B12 deficiency.
Usually if a person has no other medical history and associated symptoms then such readings are not so significant and doesn't require any treatment.
Sometimes medications used for other ailment can result in such low WBC count.
So you should discuss it with your doctor for a clinical corelation.
In the meantime you can start multivitamin supplement.
And it's good to get repeat CBC after 3 months.
Hope this helps.
Feel free for further query & follow-up.
Positive feedback & bonus are highly appreciated.