Expression of the alpha-chain gene in heterogeneous IgA immunodeficiency.
Five heterogeneous IgA-immunodeficient patients were analysed for expression of the alpha-chain gene. The number of surface IgA-bearing B cells was low in four patients. Southern blot analysis indicated no deletion of immunoglobulin structural genes coding for C alpha or alpha switching-region genes. The number of surface IgM and IgA double-bearing B cells increased in some patients. Addition of recombinant interleukin 4 (rIL-4), rIL-5, and rIL-6 to the normal B cells enhanced IgA production. However, B cells of the patients showed no or one-third lower IgA production in response to these lymphokines, even though there was proliferation. rIL-4, rIL-5, and rIL-6 induced low or no expression of alpha mRNA of the patients' B cells. These results suggested that the patients lacked B cells able to produce transcripts for the IgA heavy chain, and that some patients' B cells might be defective at the switch-recombination process from mu to alpha or from mu and alpha to alpha.
Kaneko
H
H
Department of Pediatrics, Gifu University School of Medicine, Japan.
Kondo
N
N
Motoyoshi
F
F
Mori
S
S
Kobayashi
Y
Y
Ozawa
T
T
Orii
T
T
D000293:Adolescent; D001402:B-Lymphocytes / Q000276:immunology*; D002648:Child; D004406:Dysgammaglobulinemia / Q000276:immunology*; D005260:Female; D006801:Humans; D017098:IgA Deficiency; D007070:Immunoglobulin A / Q000096:biosynthesis / Q000235:genetics*; D007075:Immunoglobulin M / Q000032:analysis; D007134:Immunoglobulin Switch Region / Q000235:genetics; D015847:Interleukin-4 / Q000502:physiology; D015848:Interleukin-5 / Q000502:physiology; D015850:Interleukin-6 / Q000502:physiology; D008213:Lymphocyte Activation / Q000187:drug effects; D008297:Male; D011043:Pokeweed Mitogens / Q000494:pharmacology; D011947:Receptors, Antigen, B-Cell / Q000032:analysis; D011994:Recombinant Proteins
D007070:Immunoglobulin A; D007075:Immunoglobulin M; D015848:Interleukin-5; D015850:Interleukin-6; D011043:Pokeweed Mitogens; D011947:Receptors, Antigen, B-Cell; D011994:Recombinant Proteins; D015847:Interleukin-4