Expression of cyclin B1 and cyclin dependent kinase inhibitor p21 in lymphocytes in patients with systemic lupus erythematosus.
OBJECTIVE
The roles of cyclins and cyclin dependent kinase (CDK) inhibitors of lymphocytes in the pathogenesis of systemic lupus erythematosus (SLE) are unclear. We measured the expression of cyclin B1 and CDK inhibitor p21 in peripheral blood lymphocytes (PBL) from patients with SLE and controls.


METHODS
PBL from 40 SLE patients with renal disease (RSLE), 40 SLE patients without renal disease (SLE), and 28 healthy control subjects were cultured with phytohemagglutinin (PHA). Bivariate distribution of cyclin B1 or p21 expression versus cellular DNA content was assessed by flow cytometry.


RESULTS
Expression of p21 in lymphocytes was significantly lower in patients with RSLE and with SLE than controls (RSLE vs controls and SLE vs controls, both p < 0.001). Expression of cyclin B1 was similar in all groups. The percentages of RSLE lymphocytes in G0/G1 and S phase were significantly reduced and elevated, respectively, compared with controls.


CONCLUSIONS
Downregulated p21 in PHA stimulated PBL from patients with SLE may be closely related to aberration of cell division in SLE lymphocytes.
Ho
Cheong-Yip
CY
Department of Chemical Pathology, The Chinese University of Hong Kong, Prince of Wales Hospital, Shatin, NT, Hong Kong.
Wong
Chun-Kwok
CK
Li
Edmund Kwok-Ming
EK
Tam
Lai-Shan
LS
Lam
Christopher Wai-Kei
CW
D000328:Adult; D000368:Aged; D002452:Cell Count; D019926:Cyclin B / Q000096:biosynthesis*; D056744:Cyclin B1; D050759:Cyclin-Dependent Kinase Inhibitor p21; D016213:Cyclins / Q000096:biosynthesis*; D004247:DNA / Q000032:analysis; D005260:Female; D005434:Flow Cytometry; D006801:Humans; D008180:Lupus Erythematosus, Systemic / Q000097:blood*; D008214:Lymphocytes / Q000187:drug effects / Q000378:metabolism*; D008297:Male; D008875:Middle Aged; D010835:Phytohemagglutinins / Q000494:pharmacology
C534699:CCNB1 protein, human; C493956:CDKN1A protein, human; D019926:Cyclin B; D056744:Cyclin B1; D050759:Cyclin-Dependent Kinase Inhibitor p21; D016213:Cyclins; D010835:Phytohemagglutinins; D004247:DNA