B-cell activity in children with malaria

Malaria Journal

Research

Japhet K Magambo¹  Joseph K Mwatha²  John N Waitumbi³  Jackson C Korir⁴ 

[1] Jomo Kenyatta University of Agriculture and Technology, Nairobi, Kenya;Kenya Medical Research Institute, Nairobi, Kenya;Walter Reed Project/Kenya Medical Research Institute, Kisumu, Kenya;Walter Reed Project/Kenya Medical Research Institute, Kisumu, Kenya;Jomo Kenyatta University of Agriculture and Technology, Nairobi, Kenya;Masinde Muliro University of Science and Technology, Kakamega, Kenya;

关键词: Systemic Lupus Erythematosus;    Malaria;    Cerebral Malaria;    Uncomplicated Malaria;    Absolute Lymphocyte Count;   

DOI  :  10.1186/1475-2875-11-66

 received in 2011-12-09, accepted in 2012-03-09,  发布年份 2012

来源: Springer

【 摘 要 】

BackgroundRecent studies implicate deficiency of red blood cell (RBC) complement regulatory proteins (CR1 and CD55) in the pathogenesis of malarial anaemia. This study explored the involvement of B cell CD21, which has an analogous role to RBC CR1.MethodsIn a case control study conducted in Kisumu District hospital, western Kenya, children with severe malaria anaemia (SMA) and those with uncomplicated malaria (UM) were assessed by flow cytometry for B cells (CD20+) numbers, expression levels of CD21 and deposition of C3dg and by ELISA for soluble CD21 (sCD21). Paired t tests were used to determine statistical significance at a = 0.05.ResultsChildren with SMA had significantly higher lymphocyte count (9,627.7 ± 8786.1 SD vs. 5,507 ± 2436 SD, P = 0.04 in the UM group) and the computed geometric mean of mature B-cell numbers based on the absolute lymphocyte count was significantly higher for SMA group: 1,823 (1,126 to 2,982, 95% CI) and 826.6 (564 to 1,220, 95% CI)] for UM group (P = 0.003). SMA group also had a higher percentage of CD20+ B cells (26.8 ± 9.7SD vs 20.9 ± 9.01 SD in the UM) (P = 0.03), indicating considerable polyclonal B-cell activation. The CD21 median flourescence intensity was lower in the SMA (246.4 ± 87.4 SD vs 369 ± 137.7 SD) (P < 0.0001), probably due to complement mediated shaving of CD21 by fixed tissue macrophages. The CD20+ B cells of SMAs had higher levels of the complement split product C3dg (18.35 ± 10 SD vs 11.5 ± 6.8 S.D), (P = 0.0002), confirming possible role of complement in CD21 removal. Unexpectedly, the SMAs had lower levels of sCD21 (226.5 ± 131.5 SD vs 341.4 ± 137.3 SD in the UM) (P < 0.0001), indicating that the shaved CD21 is not released to peripheral circulation.ConclusionsThese results implicate B-cell in pathophysiology of severe malaria that involves increased B-cell proliferation, increased complement deposition and subsequent loss of membrane-bound CD21. The loss of CD21 is not by the classical enzmatic cleavage.

【 授权许可】

Unknown   
© Korir et al; licensee BioMed Central Ltd. 2012. This article is published under license to BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.