It is hard to accept the conclusion of Rule, et al.1 regarding the presence of
A in meconium from infants with cystic fibrosis without further information about their antisera, Nonimmunologic precipitates between gut juices and goat, sheep, or bovine antisera have caused some confusion in the past. These reactions depend on nonimmunoglobulin protein reacting with proteolytic enzymes, and can be avoided by the simple expedient of using only the
-globulin fractions of antisera.2 A description of the specificity of the antiserum preparations to exocrine ("secretory")
A and "Secretory Component" is also in order to assure that they did not react with other antigens common to exocrine fluids, especially lactoferrin.3