How does rheumatoid arthritis affect the blood?

It is not unusual for Anemia or "low blood" to accompany rheumatoid arthritis. Anemia indicates a low number of red blood cells and that these cells are low in hemoglobin, the substance that carries oxygen through the body. A low white blood cell count (leukopenia) can occur as a result of Felty's syndrome which is a complication of rheumatoid Arthritis that is also characterized by enlargement of the spleen.