Immunoglobulin M: local synthesis and selective secretion in patients with immunoglobulin A deficiency

Local synthesis seems to be decisive for the selective secretion of 19S immunoglobulin M into parotid secretions. The "transport piece" is apparently not involved in the secretion of immunoglobulin M, for there is no association between the two components. The possible significance of the normal association of transport piece with secreted immunoglobulin A remains to be clarified.