Complete variable region deletion in a mu heavy chain disease protein (ROUL). Correlation with light chain secretion.
In a patient affected with chronic lymphocytic leukemia with lymphocyte surface mu and kappa determinants and vacuolated bone marrow plasma cells, the serum contained polymers of a truncated mu chain and normal-sized kappa chains. These light chains were present as monomers and covalent dimers in studies performed under dissociating conditions, but they were linked by non-covalent bridges to a portion of the serum short mu chains. The patient's urine contained a kappa type Bence-Jones protein. Study of a messenger RNA and complementary DNA from blood cells showed the abnormal mu chain to lack the entire variable region, likely due to a direct splicing of the leader peptide exon onto the CH1 exon. The production of light chains, a rare event in heavy chain diseases, appears to correlate with the occurrence of a heavy chain deletion restricted to the variable domain, likely because the non-covalently linked light chains allow these unusual heavy chains to be secreted.
CNRS URA 1172 (Immunology and Molecular Interactions), Faculté des Sciences, Poitiers, France.
M
M
Cogné
P
P
Aucouturier
A
A
Brizard
B
B
Dreyfus
F
F
Duarte
J L
JL
Preud'homme
D000595:Amino Acid Sequence; D001483:Base Sequence; D001798:Blood Proteins / Q000032:analysis; D001853:Bone Marrow / Q000473:pathology; D004247:DNA / Q000097:blood / Q000235:genetics / Q000302:isolation & purification; D005091:Exons; D006362:Heavy Chain Disease / Q000235:genetics* / Q000276:immunology / Q000473:pathology; D006801:Humans; D007122:Immunoelectrophoresis; D007147:Immunoglobulin Light Chains / Q000097:blood* / Q000235:genetics; D007135:Immunoglobulin Variable Region; D007145:Immunoglobulin kappa-Chains / Q000032:analysis; D007148:Immunoglobulin mu-Chains / Q000235:genetics*; D015451:Leukemia, Lymphocytic, Chronic, B-Cell / Q000235:genetics* / Q000276:immunology* / Q000473:pathology; D008297:Male; D008875:Middle Aged; D008969:Molecular Sequence Data; D009838:Oligodeoxyribonucleotides; D016133:Polymerase Chain Reaction; D021382:Protein Sorting Signals / Q000235:genetics; D012326:RNA Splicing; D012333:RNA, Messenger / Q000097:blood / Q000235:genetics / Q000302:isolation & purification
D001798:Blood Proteins; D007147:Immunoglobulin Light Chains; D007135:Immunoglobulin Variable Region; D007145:Immunoglobulin kappa-Chains; D007148:Immunoglobulin mu-Chains; D009838:Oligodeoxyribonucleotides; D021382:Protein Sorting Signals; D012333:RNA, Messenger; D004247:DNA