DiNonA, Inc.

We aimed to investigate the prognostic value of neutrophil-to-lymphocyte ratio (NLR) and myeloid-derived suppressor cells (MDSCs) in gastric cancer patients treated with second-line ramucirumab plus paclitaxel.

A total of 116 patients with advanced or metastatic gastric cancer who receive ramucirumab plus paclitaxel were prospectively enrolled. Fresh blood samples were collected before and after treatment, and flow cytometry was performed to assess the proportions of monocytic (mMDSCs) and granulocytic MDSCs (gMDSCs).

Median age was 58 years and 71 (61.2%) patients were male. A baseline NLR≥2.94 was associated with significantly poorer progression-free survival (PFS) and overall survival (OS) vs. an NLR<2.94 (P=0.011 and P=0.002, respectively). In multivariate analysis, an NLR≥2.94 was independently associated with poorer PFS [hazard ratio (HR)=1.58; 95% confidence interval (95% CI): 1.01-2.49, P=0.046] and OS (HR=1.77; 95% CI: 1.04-3.04, P=0.036). While mMDSC counts did not significantly change following two cycles of therapy (P=0.530), gMDSC counts decreased significantly after two treatment cycles (P=0.025) but tended to increase in patients with progressive disease after two treatment cycles (P=0.098). A progressive increase in gMDSC counts (≥44%) was associated with a significantly shorter PFS and OSvs. a gMDSC count increase <44% (P=0.001 and P=0.003, respectively).

The baseline NLR may help guide clinical decisions during ramucirumab plus paclitaxel therapy for gastric cancer. Our gMDSC kinetics data warrant further clinical validation and mechanistic investigation.

JL1, a specific epitope on CD43, is a potential biomarker for the diagnosis of acute leukemia. Although qualitative assays for detecting leukemia-specific CD43 exist, there is a need to develop quantitative assays for the same. Here, we developed two novel monoclonal antibodies (mAbs), 2C8 and 8E10, recognizing different epitopes on CD43. These clones are capable of pairing with YG5, another mAb against JL1 epitope, because they were selectively obtained using sandwich ELISA. Antigens recognized by 2C8 and 8E10 were confirmed as CD43 by western blotting using the CD43-hFC recombinant protein. When expression on various leukemic cell lines was investigated, 2C8 and 8E10 displayed a disparity in the distribution of the epitope. Enzyme assays revealed that these mAbs recognized a sialic acid-dependent epitope on CD43. Using normal thymus and lymph node paraffin-embedded tissues, we confirmed a difference in the epitopes recognized by the two mAbs that was predicted based on the maturity of the cells in the tissue. In summary, we developed and characterized two mAbs, 2C8 and 8E10, which can be used with YG5 in a sandwich ELISA for detecting leukemia-specific CD43.

Monoclonal antibodies (mAbs) recognizing Class III epitope of CD34 are essential for flow cytometric diagnosis of leukemia.

27H2 mAb was developed from a mouse alternatively immunized with human acute leukemia cell lines, KG1 and Molm-1. Using flow cytometric analysis of various leukemic cell lines and peripheral blood, immunohistochemical study of frozen tonsil, we characterized 27H2 mAb. Antigen immunoprecipitated with 27H2 mAb immunobloted with anti-CD34 mAb. A case of bone marrow sample of acute lymphoblastic leukemia (ALL) patient was obtained at CBNU Hospital. For epitope identification enzyme treatment with neuraminidase and O-sialoglycoprotein endopeptidase (OSGE) and blocking assay with known classIII mAb (HPCA-2) were done.

Only KG1 and Molm-1 revealed positive immunoreactivity. Immunohistochemical staining disclosed strong membranous immunoreactivity on high endothelial venules. Antigen immunoprecipitated by 27H2 mAb showed approximately 100 kDa sized band immunoblotted with anti-CD34 under non-reducing conditions. Epitope recognized by 27H2 mAb disclosed resistancy to both neuraminidase and OSGE treatment and completely blocked with known class III mAb preincubation. CD34 positive leukemic cells in BM of pre B cell ALL patient detected by FITC-conjugated 27H2 and HPCA-2 were identified with similar sensitivity.

A novel murine mAb recognizing class III epitope of human CD34 with high affinity, which is useful for flow cytometric diagnosis of leukemia, was developed.