Abnormal serum protein levels in infants with hyaline membrane disease--evidence of an underlying immunological disorder.

Evidence is presented that newborn infants who develop hyaline membrane disease (HMD) have higher levels of serum alpha-fetoprotein (AFP) than comparable infants who do not show evidence of the disease. A hypothesis is put forward that HMD is the result of an immune reaction between mother and infant, which may commence as early as the 2nd trimester of pregnancy. It is postulated that HMD infants, who generally have raised levels of serum IgM, produce IgM antibodies to foreign maternal IgG and that this reaction between the infant's IgM and maternal IgG accounts for the signs of systemic disease at birth. The onset of breathing during the intrapartum period may lead to an exacerbation of the immune response in the lung. It is known that AFP suppresses T-cell-dependent antibody responses. The presence of raised AFP levels may be an attempt to prevent formation of fetal or infant IgG antibodies resulting in an uncontrolled immune response and a lethal outcome.