The distribution of CD10 (NEP 24.11, CALLA) in humans and mice is similar in non-lymphoid organs but differs within the hematopoietic system: absence on murine T and B lymphoid progenitors

A comprehensive review of the literature on CD10: its function, clinical application, and prospects

CD10, a zinc-dependent metalloprotease found on the cell surface, plays a pivotal role in an array of physiological and pathological processes including cardiovascular regulation, immune function, fetal development, pain response, oncogenesis, and aging. Recognized as a biomarker for hematopoietic and tissue stem cells, CD10 has garnered attention for its prognostic potential in the progression of leukemia and various solid tumors. Recent studies underscore its regulatory significance and therapeutic promise in combating Alzheimer's disease (AD), and it is noted for its protective role in preventing heart failure (HF), obesity, and type-2 diabetes. Furthermore, CD10/substance P interaction has also been shown to contribute to the pain signaling regulation and immunomodulation in diseases such as complex regional pain syndrome (CRPS) and osteoarthritis (OA). The emergence of COVID-19 has sparked interest in CD10's involvement in the disease's pathogenesis. Given its association with multiple disease states, CD10 is a prime therapeutic target; inhibitors targeting CD10 are now being advanced as therapeutic agents. This review compiles recent and earlier literature on CD10, elucidating its physicochemical attributes, tissue-specific expression, and molecular functions. Furthermore, it details the association of CD10 with various diseases and the clinical advancements of its inhibitors, providing a comprehensive overview of its growing significance in medical research.

Human and mouse early B cell development: So similar but so different

Early B cell development in the bone marrow ensures the replenishment of the peripheral B cell pool. Immature B cells continuously develop from hematopoietic stem cells, in a process guided by an intricate network of transcription factors as well as chemokine and cytokine signals. Humans and mice possess somewhat similar regulatory mechanisms of B lymphopoiesis. The continuous discovery of monogenetic defects that impact early B cell development in humans substantiates the similarities and differences with B cell development in mice. These differences become relevant when targeted therapeutic approaches are used in patients; therefore, predicting potential immunological adverse events is crucial. In this review, we have provided a phenotypical classification of human and murine early progenitors and B cell stages, based on surface and intracellular protein expression. Further, we have critically compared the role of key transcription factors (Ikaros, E2A, EBF1, PAX5, and Aiolos) and chemo- or cytokine signals (FLT3, c-kit, IL-7R, and CXCR4) during homeostatic and aberrant B lymphopoiesis in both humans and mice.

Long-term outcome of intravitreal anti-vascular endothelial growth factor treatment for pachychoroid neovasculopathy

To compare the long-term effectiveness of intravitreal anti-vascular endothelial growth factor (VEGF) treatment for pachychoroid neovasculopathy (PNV), polypoidal choroidal vasculopathy/aneurysmal type 1 neovascularization (PCV/AT1), and typical neovascular age-related macular degeneration (nAMD). Forty-one eyes with PNV, 68 eyes with PCV/AT1, and 56 eyes with typical nAMD were retrospectively included for analysis. All patients were treatment-naïve and received a three-monthly loading injection of anti-VEGF, followed by further injections, as required. The visual and anatomical outcomes after treatment were evaluated up to 36 months from baseline. No significant intergroup difference was found in terms of best-corrected visual acuity (BCVA) and changes in central foveal thickness at 12, 24, and 36 months after the baseline. In addition, no significant difference was found between the groups regarding the proportions of improved or worsened (increased or decreased more than 3-lines) visual acuity. However, the PNV group participants received significantly fewer anti-VEGF injections (11.7 ± 6.9) than those in the PCV/AT1 (12.4 ± 7.0; P = 0.031) and typical nAMD groups (13.2 ± 7.4; P = 0.016). The incidence of macular atrophy (MA) development was also significantly lower for the PNV (4/41 eyes, 9.8%) than the typical nAMD (15/56 eyes, 26.8%; P = 0.033) eyes. There was no significant difference between PNV, PCV/AT1, and typical nAMD regarding visual acuity improvement after anti-VEGF treatment over 36 months. However, the number of injections for PNV was significantly lower compared to that for PCV/AT1 and typical nAMD, and the incidence of MA development was significantly lower than in typical nAMD.

Expansion of CD10neg neutrophils and CD14+HLA-DRneg/low monocytes driving proinflammatory responses in patients with acute myocardial infarction

Immature neutrophils and HLA-DR^neg/low monocytes expand in cancer, autoimmune diseases and viral infections, but their appearance and immunoregulatory effects on T-cells after acute myocardial infarction (AMI) remain underexplored. We found an expansion of circulating immature CD16⁺CD66b⁺CD10^neg neutrophils and CD14⁺HLA-DR^neg/low monocytes in AMI patients, correlating with cardiac damage, function and levels of immune-inflammation markers. Immature CD10^neg neutrophils expressed high amounts of MMP-9 and S100A9, and displayed resistance to apoptosis. Moreover, we found that increased frequency of CD10^neg neutrophils and elevated circulating IFN-γ levels were linked, mainly in patients with expanded CD4⁺CD28^null T-cells. Notably, the expansion of circulating CD4⁺CD28^null T-cells was associated with cytomegalovirus (CMV) seropositivity. Using bioinformatic tools, we identified a tight relationship among the peripheral expansion of immature CD10^neg neutrophils, CMV IgG titers, and circulating levels of IFN-γ and IL-12 in patients with AMI. At a mechanistic level, CD10^neg neutrophils enhanced IFN-γ production by CD4⁺ T-cells through a contact-independent mechanism involving IL-12. In vitro experiments also highlighted that HLA-DR^neg/low monocytes do not suppress T-cell proliferation but secrete high levels of pro-inflammatory cytokines after differentiation to macrophages and IFN-γ stimulation. Lastly, using a mouse model of AMI, we showed that immature neutrophils (CD11b^posLy6G^posCD101^neg cells) are recruited to the injured myocardium and migrate to mediastinal lymph nodes shortly after reperfusion. In conclusion, immunoregulatory functions of CD10^neg neutrophils play a dynamic role in mechanisms linking myeloid cell compartment dysregulation, Th1-type immune responses and inflammation after AMI.

[Clinical features and prognosis in CD10(-) pre-B acute lymphoblastic leukemia]

目的

分析CD10阴性的前B急性淋巴细胞白血病（CD10⁻pre B-ALL）患者的临床特征和预后。

方法

对6例成人CD10⁻ pre B-ALL患者的临床和实验室资料进行回顾性分析，结合文献复习明确该类型患者的临床特征及预后。

结果

CD10⁻pre B-ALL占ALL的1.5%（6/409），占B-ALL的1.8%（6/343），占pre B-ALL的11.5%（6/52）。6例患者均为男性，中位年龄为33.5岁，起病时中位WBC为101.78×10⁹/L，所有患者均伴有MLL-AF4融合基因表达。5例患者经1个疗程诱导化疗即获得完全缓解（CR），1例患者经3个疗程化疗后才获得CR。2例患者在CR₁期行异基因造血干细胞移植（allo-HSCT），1例患者CR后短期内即复发，在CR₂期行allo-HSCT。1例患者正在等待移植。2例未移植患者1例复发死亡，1例尚处于缓解状态。

结论

CD10⁻pre B-ALL是一类具有独特临床特征的成人ALL亚型，发生率较低，常见于男性，起病时白细胞水平较高，MLL-AF4融合基因表达率高，常规化疗具有较高的缓解率，但易复发，allo-HSCT有可能改善其预后。

Constitutive Kit activity triggers B-cell acute lymphoblastic leukemia-like disease in mice

Acute lymphoblastic leukemia (ALL) is the most common childhood malignancy and, in most cases, is of pro- or pre-B cell origin (B-ALL). The receptor tyrosine kinase KIT is expressed by hematopoietic stem and precursor cells. Gain-of-function mutations of KIT cause systemic mastocytosis, which is characterized by abnormal accumulations of mast cells. We previously reported a mouse model of mastocytosis based on conditional expression of a constitutively active Kit protein. Half of these animals developed leukemic disease of B-lineage origin. Herein, we report that this condition bears striking similarities to human B-ALL. The immuno-phenotype of the leukemic cells was compatible with a pro-B-cell origin, as was the finding of immunoglobulin heavy-chain gene rearrangements in all cases, whereas light-chain loci were mostly not rearranged. Leukemogenesis was independent of pre-B-cell receptor expression. Primary leukemic cells and permanent cell lines derived from these were serially transplantable and rapidly killed the recipients. In a few animals, the leukemia was of T-cell origin with abnormal CD4/8 double-positive T-cell precursors dominating in the circulation. In summary, we report a novel ALL mouse model that may prove useful for in vivo drug testing and identification of novel oncogenic mutations and principles.

The utility of immunohistochemistry for the identification of hematopoietic and lymphoid cells in normal tissues and interpretation of proliferative and inflammatory lesions of mice and rats

Expression of antigens in cells and tissues can be readily studied immunohistochemically with the use of antibodies. A panel of antibodies to cell-specific markers can be used to diagnose lesions, including tumors, in the hematopoietic and lymphoid systems. This review discusses the use of readily available antibodies and procedures to identify antigens expressed in normal tissues and in proliferative and inflammatory lesions in formalin-fixed, paraffin-embedded (FFPE) murine specimens.

CD10+ stromal cells form B-lymphocyte maturation niches in the human bone marrow

In adult mammals, early B-lymphopoiesis takes place in the bone marrow in close association with stromal cells. Both the phenotype of the stromal cells and the molecules involved in this essential interaction are as yet inadequately described. In this study, all benign, differentiating B-cells (Pax-5+ lymphoid cells) are shown, by using two-colour immunohistochemistry on biopsies from human bone marrow, to be in close contact with scant dendritic CD10+ stromal cells until they leave via the sinusoids. This CD10+ stromal cell population does not fully overlap with the VCAM-1+ stromal cell population. Furthermore, using a set of B-cell differentiation markers (TdT, Pax-5, and CD20), B-cell development is shown to be spatially oriented, with maturation progressing towards bone marrow sinusoids. In conclusion, CD10+ stromal cells form distinct B-lymphocyte maturation niches in the human bone marrow.

Human B cells express a CD45 isoform that is similar to murine B220 and is downregulated with acquisition of the memory B-cell marker CD27

BACKGROUND

Differences between human and murine B cells exist at all stages of B-cell development, including the stage of memory B-cell formation. B cells in mice are identified with the pan-B-cell-specific CD45 isoform, B220. In initial studies in humans, it appeared that B220 expression did not include all B cells. This study was performed to expand on those preliminary findings.

METHODS

Multiparameter flow cytometric detection of B220 expression on B cells was combined with a variety of B-cell markers.

RESULTS

In contrast to mice, B220 was not a pan-B-cell marker in humans but was downregulated in the majority of B cells that acquired the human memory B-cell marker, CD27, whereas a minor memory B-cell subset remained B220(+), suggesting differences in differentiation.

CONCLUSIONS

The B220 isoform in humans is developmentally regulated in humans, tied to the acquisition of a memory phenotype, and as such can be used as a differentiation-specific CD45 isoform, akin to the use of CD45 isoforms to distinguish between naive and memory T-cell subsets. Patients with immunodeficiency disorders, associated with defective memory B-cell generation and absent or reduced CD27(+) B cells, showed a corresponding lack of B220 downregulation consistent with altered differentiation of B-cell subsets.

The expression of ETV6/CBFA2 (TEL/AML1) is not sufficient for the transformation of hematopoietic cell lines in vitro or the induction of hematologic disease in vivo

ETV6/CBFA2 (TEL/AML1) is the most frequent genetic abnormality associated with acute lymphoblastic leukemias in children, and is associated with a favorable prognosis. To investigate the influence of ETV6/CBFA2 on cellular transformation, the fusion gene was cloned into a murine ecotropic retroviral vector and transduced into IL-3-dependent Ba/F3 and 32Dcl.3 and IL-7-dependent IxN/2b murine hematopoietic cell lines. Different variants of ETV6/CBFA2, corresponding to CBFA2 alternatively spliced variants, and the reciprocal product CBFA2/ETV6, were stably expressed in each of these cell lines. However, although Western blot analysis demonstrated expression of each variant, none of the stable cell lines expressing CBFA2/ETV6 or the variants conferred factor-independent growth. We further investigated the effect of ETV6/CBFA2 expression in vivo by generating transgenic mice in which expression of the fusion was directed to lymphoid cells using the immunoglobulin heavy chain enhancer/promoter. Four founder mice were identified showing transmission and expression of the chimeric product. The mice were bred for five generations and followed for more than 24 months. The mice did not develop a malignant hematologic disorder, nor did they display histopathologic, morphologic, or immunophenotypic abnormalities, although ETV6/CBFA2 expression was confirmed in each line. We conclude that the expression of ETV6/CBFA2 alone is not sufficient for induction of growth factor independence in hematopoietic cell lines or hematologic disease in transgenic mice.

NCL-CD10-270: a new monoclonal antibody recognizing CD10 in paraffin-embedded tissue

CD10 (CALLA) antigen is expressed in a wide variety of epithelial and nonepithelial tissues, but its most significant application is in the diagnosis and classification of certain types of malignant lymphoma and leukemia. CD10 is expressed in a high percentage of cases of acute lymphoblastic leukemia (ALL), follicular lymphoma, Burkitt's lymphoma, and some hematopoietic tumors. Although the antigen is not lineage specific, CD10 expression is widely used to define subgroups within B-ALL and is a useful tool for detecting the presence of leukemic blasts in the bloodstream. Currently available monoclonal antibodies to CD10 have been found to be effective only in fresh-frozen tissue and for techniques such as flow cytometry. We have used a recombinant protein corresponding to the whole of CD10 to generate a monoclonal antibody that is effective in paraffin-embedded tissue sections. We have used this antibody to assay for the presence of CD10 on a range of normal and pathological tissues. Strong staining was seen in lymphoid germinal centers, renal tubules, glomeruli, syncytiotrophoblast, hepatic parenchymal canaliculi, B-lineage ALL, follicle center cell lymphoma, and a proportion of cases of large-B-cell lymphoma. We believe that this antibody will be of value in the characterization of malignant lymphoma, in particular the differential diagnosis of small-B-cell lymphoma and subtyping of lymphoblastic leukemia, as well as the investigation of the significance of expression of CD10 in other normal and pathological tissues.

B-cell development: a comparison between mouse and man

A common variable immunodeficiency (CVID) patient, who carries mutations on both alleles of the gene encoding the surrogate light chain component lambda 5/14.1, shows a similar phenotype of B-cell deficiency as the lambda 5-deficient mutant mouse. As discussed here by Paolo Ghia and colleagues, this points to a remarkably similar developmental pathway of B cells in humans and mice.

Immunodissection of the human proximal nephron: flow sorting of S1S2S3, S1S2 and S3 proximal tubular cells

We report on the use of several proximal tubular cell (PTC) surface markets and corresponding antibodies in fluorescence-activated cell sorting (FACS), and their ability to identify and flow sort cells of defined proximal tubular origin (S1S2S3) or of defined proximal subsegmental origin (S1S2 only/S3 only). We tested monoclonal/polyclonal antibodies directed against five different surface peptidases [leucine aminopeptidase (LAP), neutral endopeptidase 24.11 (NEP), dipeptidyl peptidase IV (DPPIV), aminopeptidase A (APA) and gamma-glutamyl transferase (gamma-GT)], the S3 segment-specific marker intestinal type alkaline phosphatase (iAP) and an S1S2 marker (TN20-antigen), originally proposed as a surface marker for interstitial fibroblasts. Segmental (proximal tubular vs. distal tubular) and proximal subsegmental (S1S2 vs. S3) expression of all five surface peptidases and TN20 antigen were first assessed by comparing immunohistochemical staining on normal human kidney tissue with staining for well-known segment-specific differentiation markers (intestinal type alkaline phosphatase, Tamm-Horsfall protein) on adjacent sections. All five peptidases were found to be expressed to a certain degree in all subsegments (S1 S2 and S3) of the proximal nephron, whereas expression was never seen in the more distal parts of the nephron. Flow cytometry was performed on cells obtained following gradient purification of collagenase-digested human renal tissue. Labeling cells for expression of LAP, NEP or DPPIV resulted in high yields of specifically labeled PTC (S1S2S3 origin). Labeling with anti-LAP resulted in the clearest distinction between positive and negative cell subpopulations, and therefore LAP was considered the best PTC marker for use in FACS. iAP histochemical staining on sorted cells showed that flow sorting with monoclonal antibody (moAb) 250 (anti-intestinal type alkaline phosphatase) allowed sorting of S3 cells with > 90% purity. Likewise, moAb TN20 enabled us to obtain a highly purified S1S2 population as confirmed by the absence of iAP on sorted cells.

Activity of neutral endopeptidase and aminopeptidase N in mouse thymic stromal cells which bind double-positive thymocytes

The activity of two peptidases was determined in immortalized lines of thymic stromal cells. A line of total stromal cells (T-TG-St) was grown from transgenic mouse expressing temperature-sensitive SV40 T antigen under the control of the regulatory elements of the mouse major histocompatibility complex class I gene. From these cells we isolated a subset (DP-TG-St) that binds thymocytes which are mainly CD4+8+. We also assayed a clone of fetal thymic epithelial cells (BA/10) that binds CD4+8+ thymocytes. Both lines of double -positive cell-binding stroma exhibited strong activity of two peptidases, neutral endopeptidase (NEP; EC 3.4.24.11) and aminopeptidase N (APN; EC 3.4.11.2). In contrast, the activity of both enzymes was very low in the total thymic stromal line. Use of the specific inhibitors confirmed that these two enzymes were responsible for the activity observed but also suggested the presence of additional unidentified aminopeptidase(s) in the same stromal cells. The high activity of the two peptidases on stromal cells that bind thymocytes at the double-positive stage raises the possibility that they might contribute to the microenvironment of the developing thymocytes.