Expedited CO 2 respiration in people with Miltenberger erythrocyte phenotype GP.Mur

In Southeast Asia, Miltenberger antigen subtype III (Mi.III; GP.Mur) is considered one of the most important red blood cell antigens in the field of transfusion medicine. Mi.III functions to promote erythrocyte band 3 expression and band 3-related HCO 3 − transport, with implications in blood CO 2 metabolism. Could Mi.III affect physiologic CO 2 respiration in its carriers? Here, we conducted a human trial to study the impacts of Mi.III expression in respiration. We recruited 188 healthy, adult subjects for blood typing, band 3 measurements and respiratory tests before and after exercise. The 3-minute step exercise test forced the demand for CO 2 dissipation to rise. We found that immediately following exercise, Mi.III + subjects exhaled CO 2 at greater rates than Miltenberger-negative subjects. Respiration rates were also higher for Mi.III + subjects immediately after exercise. Blood gas tests further revealed distinct blood CO 2 responses post-exercise between Mi.III and non-Mi.III. In contrast, from measurements of heart rates, blood O 2 saturation and lactate, Mi.III phenotype was found to be independent of one’s aerobic and anaerobic capacities. Thus, Mi.III expression supported physiologic CO 2 respiration. Conceivably, Mi.III + people may have advantages in performing physically enduring activities.