Kappa-chain deficiency. An immunoglobulin disorder.

Since kappa-chain deficiency is an unusual condition, we studied the clinical and 
laboratory findings in a patient with this deficiency. The patient had 
cystic fibrosis with concurrent malabsorption, diabetes mellitus and IgA deficiency. The 
serum levels of IgM and IgG were 0.85 and 7.22 mg 
per milliliter, respectively. Kappa type IgM and IgG was not present 
in serum and external secretions; gamma, mu and lambda chains were 
probably polyclonal in character. Antibodies against kappa chains were not detected 
in either the patient or the mother. Plasma cells containing kappa-type 
immunoglobulins were absent in jejunum samples and bone marrow; kappa-chainbearing B 
lymphocytes could not be detected in blood and bone marrow. The 
serum of one of the patient's sisters contained trace amounts of 
kappa-type immunoglobulins. The patient displays a complete absence of kappa- type 
immunoglobulins, probably owing to a genetic defect. 