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.