Diagnosis and differential diagnosis value of immune marker CCR7 in chronic lymphocytic leukemia and other chronic B-cell lymphoproliferative disorders / 中华检验医学杂志

ABSTRACT

Objective:To investigate the clinical significance of cc-chemokine receptor 7 (CCR7) as a potential diagnostic or differential marker for chronic lymphocytic leukemia (CLL).Methods:A total number of 643 patients with B-cell chronic lymphoproliferative diseases (B-CLPD) admitted to the First Affiliated Hospital of Nanjing Medical University from January 2015 to December 2018 were enrolled. The patients included 327 cases of CLL, 58 cases of mantle cell lymphoma (MCL), 34 cases of follicular lymphoma (FL), 36 cases of marginal zone lymphoma (MZL), 10 cases of hair-cell leukemia or its variants (HCL/HCLV-v), 40 cases of Waldorf′s macroglobulinemia (WM), 48 cases of CD5 +B-cell chronic lymphoproliferative disease unclassified (B-CLPD-U) and 90 cases of CD5 -B-CLPD-U. At the same time, 20 samples from healthy people from the medical examination center of our hospital were used as normal controls. Flow cytometry was used to detect the immune-phenotype and CCR7 expression level in B-CLPD patients, and Fluorescence in situ hybridization (FISH) was used to analyze the genomic alterations the ataxia telangiectasia mutant gene (ATM) deletion, the 13q14 deletion, the P53 deletion and trisomy 12. Sanger sequencing was used to analyze gene mutations of splicing factor 3B subunit 1 (SF3B1), NOTCH1, tumor protein 53 (TP53) and immunoglobulin heavy chain variable region (IGHV). Measurement data were compared by Mann-Whitney test, and the positive rates were compared by chi-square test. The diagnostic value and optimal positive cutoff value of CCR7 were calculated using receiver operating characteristic (ROC) curve. Results:The positive rates of CCR7 expression in typical CLL and atypical CLL were 90.8% (257/283) and 84.1% (37/44), respectively, and there was no significant difference of the positive rates (χ 2=1.228, P=0.268) between groups. The positive expression rates of CCR7 in CLL, MCL, CD5 +B-CLPD-U, CD5 -B-CLPD-U, FL, WM, HCL/HCL-v and MZL were 89.9% (294/327), 10.3% (6/58), 6.3% (3/48), 8.9% (8/90), 0, 0, 0 and 13.9% (5/36) respectively, and the median mean fluorescence intensity (MFI) was 278 (246, 307), 114 (106, 128), 112 (106, 117), 110 (104, 121), 108 (105, 119), 111 (105, 124), 112 (108, 115) and 109 (105, 120) respectively. Compared with CLL, the positive expression rates of CCR7 in other types of B-CLPDs were lower significantly (χ 2=181.3, 177.8, 232, 164.7, 180.8, 62.6, 129, P<0.01). In addition, the sensitivity, specificity and accuracy of CCR7 for distinguishing CLL from other types of B-CLPD were 89.9%, 93.0% and 92.3%, respectively. The positive expression rate of CD49d in CCR7 +CLL patients was 13.9%, which was significantly lower than that in CCR7 -CLL patients (42.1%) (χ 2=7.6, P=0.01). The coincidence rate of 13q14 deletion was 50.3% in CCR7 +CLL patients, which was significantly higher than that in CCR7 -CLL patients (20%) (χ 2=6.56, P=0.01). Conclusions:The CC-chemokine receptor 7 (CCR7) antigen is an effective marker for the diagnosis and identification of chronic lymphocytic leukemia (CLL). The expression level of CCR7 in clinical specimens can distinguish CLL from other pathological subtypes of B-CLPDs.