Distribution of lymphocyte subsets in bone marrow and peripheral blood is associated with haptoglobin type. Binding of haptoglobin to the B-cell lectin CD22.
Haptoglobin is an acute phase protein showing a genetic polymorphism with 3 major types: Hp 1-1, Hp 2-1, and Hp 2-2. In this study, flow cytometric analysis demonstrated that all three haptoglobin types bind to CD22 on human B-lymphocytes with equal affinity. Comparison of reference values for lymphocyte subsets in peripheral blood and bone marrow showed significant differences between haptoglobin types. Haptoglobin 2-2 is associated with higher peripheral B-lymphocyte counts (P < 0.001) and CD4+ T-lymphocyte counts (P < 0.05). In bone marrow, CD4+ T-cell percentages were highest (P < 0.001) but B-cell percentages were lowest (P < 0.001) in haptoglobin 2-2 type. A negative correlation between serum haptoglobin 1-1 concentration and peripheral B-cell counts was observed (r = -0.663). Our results suggest that haptoglobin is involved in lymphocyte distribution. The present findings are a potential cause of over- or underestimation of lymphocyte subset counts in the clinical staging of immunodeficiency diseases.
Langlois
M
M
Central Laboratory, University Hospital Gent, Belgium.
Delanghe
J
J
Philippé
J
J
Ouyang
J
J
Bernard
D
D
De Buyzere
M
M
Van Nooten
G
G
Leroux-Roels
G
G
D000328:Adult; D000368:Aged; D015703:Antigens, CD / Q000378:metabolism*; D000944:Antigens, Differentiation, B-Lymphocyte / Q000378:metabolism*; D001854:Bone Marrow Cells; D002097:C-Reactive Protein / Q000032:analysis; D015815:Cell Adhesion Molecules / Q000378:metabolism*; D005260:Female; D005434:Flow Cytometry; D016650:Fluorescein-5-isothiocyanate; D005787:Gene Frequency; D006242:Haptoglobins / Q000235:genetics / Q000378:metabolism*; D006454:Hemoglobins / Q000378:metabolism; D006801:Humans; D007700:Kinetics; D037102:Lectins; D007958:Leukocyte Count; D016131:Lymphocyte Subsets / Q000166:cytology* / Q000378:metabolism; D008297:Male; D008875:Middle Aged; D011110:Polymorphism, Genetic; D011485:Protein Binding; D012016:Reference Values; D051918:Sialic Acid Binding Ig-like Lectin 2
D015703:Antigens, CD; D000944:Antigens, Differentiation, B-Lymphocyte; C497867:CD22 protein, human; D015815:Cell Adhesion Molecules; D006242:Haptoglobins; D006454:Hemoglobins; D037102:Lectins; D051918:Sialic Acid Binding Ig-like Lectin 2; D002097:C-Reactive Protein; D016650:Fluorescein-5-isothiocyanate