Milk antibodies in pulmonary inhalation.

To determine the association between inhalation and increased circulating milk antibodies, the presence of milk precipitins and haemagglutinating titres of antibody to casein and lactalbumin were determined in a series of 100 children studied by radionuclide 'milk scan' and/or barium swallow for possible milk inhalation. Sixty-five were investigated because of reflux and/or inhalation (REFLUX), while 35 were evaluated after near-miss sudden infant death (SID). Inhalation was demonstrated in 23/65 Reflux and 9/35 Sid patients. The incidence of milk precipitins was 22% (5/23) of the REFLUX with demonstrable inhalation, 12% (5/42) of the REFLUX without demonstrable inhalation, 0% (0/23) SID and 2% (21/1005) of an unselected series of hospital patient sera. The incidence of milk precipitins was increased in cases with demonstrated inhalation and lower respiratory tract symptoms. Determination of antibody titres to casein and lactalbumin did not provide additional benefit in the diagnosis of milk inhalation. Detection of milk precipitins can provide additional support to the diagnosis of milk inhalation.