title: Sequential assay of human milk immunoglobulins shows a predominance of lambda chains.
abstract: BACKGROUND
  Little is known of the light chains associated to heavy chains in secretions immunoglobulins. We investigated the partition of light chains in a mucosal fluid of easy access and major physiologic importance: human milk.
  
  
  METHODS
  This study provides a sequential analysis of IgA, lambda and kappa chains levels in human milk during the first days of lactation. The levels of IgA alpha-chain and of lambda and kappa light chains of immunoglobulins were assayed in 162 samples of normal human milk collected during the first night of lactation, using a classical immunonephelometric assay. A specific enzyme-linked immunosorbent assay was developed to specifically measure the levels of IgA-linked light chains, yielding similar values. Ten samples of normal human serum obtained from healthy adults were tested in parallel.
  
  
  RESULTS
  The highest levels were observed during the first 3 days of lactation, and a plateau appeared for the three proteins after day 4. Mean lambda chains levels were consistently higher than these of kappa chains, resulting in a reversed kappa/lambda ratio, significantly different from the classical 2:1 serum ratio confirmed with this method on control samples.
  
  
  CONCLUSIONS
  This study indicates that milk immunoglobulins use an unusual partition of light chains, especially in IgA.
authors.affiliation: Laboratoire d'Immunologie, Faculté de Médecine de Nancy Vandoeuvre les Nancy, France.
authors.forename: C M
authors.initials: CM
authors.lastname: Molé
authors.forename: P M
authors.initials: PM
authors.lastname: Montagne
authors.forename: M C
authors.initials: MC
authors.lastname: Béné
authors.forename: G C
authors.initials: GC
authors.lastname: Faure
mesh_terms: D006801:Humans; D007071:Immunoglobulin A, Secretory / Q000737:chemistry*; D007145:Immunoglobulin kappa-Chains / Q000378:metabolism; D007146:Immunoglobulin lambda-Chains / Q000378:metabolism*; D007774:Lactation; D008895:Milk, Human / Q000276:immunology*; D013997:Time Factors
chemical_list: D007071:Immunoglobulin A, Secretory; D007145:Immunoglobulin kappa-Chains; D007146:Immunoglobulin lambda-Chains