Erythropoietin treatment is associated with an augmented immune response to the influenza vaccine in hematologic patients.

The objective of this study was to examine whether treatment with recombinant human erythropoietin (rHuEPO), previously found to be associated with a positive effect on cell-mediated immunity and humoral immunity (hepatitis B vaccine), is associated with an improved response to the seasonal influenza (flu) vaccine. Three groups received flu vaccine: healthy controls, hematologic patients not treated with rHuEPO ("No EPO" group), and hematologic patients receiving rHuEPO for their anemia ("EPO" group). Anti-flu Ab titer was measured (complement fixation test) from blood samples drawn before and approximately 3-4 weeks, 7-8 weeks and 4 months after vaccination. Nineteen healthy subjects were compared with 17 No EPO and 17 EPO patients. Mean ages were 59.5, 61.3, and 73.1 years, respectively (EPO patients were older; p = 0.005). In the healthy group, the percentage of those sustaining only a partial (twofold) response, a strong (fourfold or greater) response, and an overall response (combined partial and strong responses) were 31.6%, 57.9%, and 89.5%, respectively. In the No EPO group, values were 35.3%, 17.6%, and 52.9%, respectively. EPO group results were similar to those of the healthy controls: 23.5%, 58.8%, and 82.4% (p = 0.016, EPO vs. No EPO). In conclusion, hematologic patients (NoEPO group) respond poorly to the flu vaccine, compared with healthy subjects, and rHuEPO treatment is associated with an improved immune response to the flu vaccine in hematologic patients, with titers similar to those of healthy subjects.