OBJECTIVETo analyze and summarize clinical manifestation of hemolytic disease of the newborn (HDN) due to anti-M.

METHODSData of one case of HDN due to anti-M and the reports of 21 cases seen in the past 20 years at the home country were reviewed and analyzed.

RESULTSThere was an increasing number of reports of cases with HDN due to anti-M. Among the 22 cases, four were the first fetus. Of 18 infants, ten were male, and eight were female. The blood group was MN in 19/21 infants, and was M in 2/21 infants. The blood group was N in 10/21 mothers, and was NN in 11/21 mothers. Among the 18 infants, the direct antiglobulin test of 7 infants were positive, of 4 infants were dubiously positive, and of 7 infants was negative. Among the 16 infants, the antibody release test of 13 infants was positive, and of 3 infants were negative. Among 17 infants, the free antibody test of all was positive. Among the 21 mothers, the anti-M of IgG were positive in all mothers, and along with IgM in 11 mothers. The anti-M of IgG was positive in all infants. Mild or severe anemia and icterus were found in all cases. Among the 15 cases, jaundice was evident on the 1st day of life in 11 cases. Among 13 cases, marked elevation of both indirect- and direct-reacting bilirubin levels was reported in 4 cases. Phototherapy was applied when jaundice became evident. High-dose intravenous immunoglobulin was given to 4/15 cases. Exchange transfusion were performed in 8 of 22 cases. Three cases died, and 19 cases were cured.

CONCLUSIONHDN of varying degrees of severity has been reported in association with anti-M and can even lead to intrauterine deaths or requiring treatment with exchange transfusion. If the mother has a history of prior intrauterine deaths, abortion, hydrops fetalis, severe fetal anemia or infertile, MN blood group and anti-M antibodies should be tested after excluding the possibility of other causes and HDN due to ABO or Rh blood group incompatibility. As the efficacy of phototherapy increases, the role of exchange transfusion in acute management is rapidly decreasing. High-dose intravenous immunoglobulin and/or intramuscular metalloporphyrins may further reduce the need for exchange transfusion. The exchange transfusion may be performed through peripheral arterial (drawn out) and venous (infused in) lines.