Frequencies of interleukin-5 mRNA-producing cells in healthy individuals and in immunoglobulin-deficient patients, measured by in situ hybridization.
Interleukin-5 (IL-5) has previously been demonstrated to enhance immunoglobulin synthesis, especially IgA. Thus, it could be hypothesized that a defect production of IL-5 may cause immunoglobulin deficiency. We have analysed the frequency of IL-5 mRNA-producing cells in healthy adults and in patients with common variable immunodeficiency or selective IgA deficiency. Unstimulated lymphocytes were rarely found to synthesize IL-5 as measured by in situ hybridization. However, pokeweed mitogen and several other activating ligands induced the synthesis of IL-5 mRNA in peripheral blood and spleen lymphocyte cultures. After pokeweed mitogen activation, the number of IL-5 mRNA-producing cells most often peaked on day 3 with a maximal frequency of around 1-2% of mononuclear cells. In a kinetic study we were unable to detect any peak frequency differences between healthy controls (mean 0.44%) and 20 patients (mean 0.58%). Thus, although IL-5 has been reported to be an important regulator of IgA synthesis, a defect production does not seem to be the underlying mechanism in human immunoglobulin deficiency.
Department of Clinical Immunology, NOVUM, Karolinska Institute, Huddinge Hospital, Sweden.
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Smith
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Möller
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Severinson
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Hammarström
D000328:Adult; D000361:Agammaglobulinemia / Q000235:genetics / Q000276:immunology* / Q000473:pathology; D000368:Aged; D002478:Cells, Cultured; D004406:Dysgammaglobulinemia / Q000235:genetics / Q000276:immunology* / Q000473:pathology; D005260:Female; D006801:Humans; D017098:IgA Deficiency; D015848:Interleukin-5 / Q000235:genetics*; D007958:Leukocyte Count; D008213:Lymphocyte Activation; D008214:Lymphocytes / Q000378:metabolism*; D008297:Male; D008875:Middle Aged; D009693:Nucleic Acid Hybridization; D011043:Pokeweed Mitogens / Q000494:pharmacology; D012333:RNA, Messenger / Q000032:analysis / Q000096:biosynthesis*; D012016:Reference Values
D015848:Interleukin-5; D011043:Pokeweed Mitogens; D012333:RNA, Messenger