No Evidence that Knops Blood Group Polymorphisms Affect Complement Receptor 1 Clustering on Erythrocytes

• Published in: Scientific reports Vol. 7; no. 1; pp. 17825 - 13
• Main Authors: Swann, O. V., Harrison, E. M., Opi, D. H., Nyatichi, E., Macharia, A., Uyoga, S., Williams, T. N., Rowe, J. A.
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 19-12-2017; Nature Publishing Group
• Subjects: 14/1; 14/19; 14/63; 631/208/248/144; 631/250/2501; Antigens; Blood diseases; Blood Group Antigens - genetics; Blood groups; Child; Children; Cluster Analysis; Complement receptors; Confocal microscopy; Copy number; Erythrocyte Membrane - genetics; Erythrocytes; Erythrocytes - physiology; Female; Gene Dosage - genetics; Genotype; Genotype & phenotype; Genotypes; Humanities and Social Sciences; Humans; Immune clearance; Immunofluorescence; Kenya; Male; multidisciplinary; Polymorphism, Genetic - genetics; Receptors, Complement 3b - genetics; Science; Science (multidisciplinary); Kenya
• ISSN: 2045-2322; 2045-2322
• DOI: 10.1038/s41598-017-17664-9

Clustering of Complement Receptor 1 (CR1) in the erythrocyte membrane is important for immune-complex transfer and clearance. CR1 contains the Knops blood group antigens, including the antithetical pairs Swain-Langley 1 and 2 (Sl1 and Sl2) and McCoy a and b (McC
a
and McC
b
), whose functional effects are unknown. We tested the hypothesis that the
Sl
and
McC
polymorphisms might influence CR1 clustering on erythrocyte membranes. Blood samples from 125 healthy Kenyan children were analysed by immunofluorescence and confocal microscopy to determine CR1 cluster number and volume. In agreement with previous reports, CR1 cluster number and volume were positively associated with CR1 copy number (mean number of CR1 molecules per erythrocyte). Individuals with the
McC
b
/McC
b
genotype had more clusters per cell than
McC
a
/
McC
a
individuals. However, this association was lost when the strong effect of CR1 copy number was included in the model. No association was observed between
Sl
genotype, sickle cell genotype, α+thalassaemia genotype, gender or age and CR1 cluster number or volume. Therefore, after correction for CR1 copy number, the
Sl
and
McCoy
polymorphisms did not influence erythrocyte CR1 clustering, and the effects of the Knops polymorphisms on CR1 function remains unknown.