Department of Veterinary Clinical Pathology, College of Veterinary Medicine & Institute of Veterinary Science, Kangwon National University, 1 Kangwondaehak-gil, Chuncheon, Gangwon-do, 24341, Republic of Korea.
Department of Veterinary Internal Medicine, College of Veterinary Medicine, Kangwon National University, 1 Kangwondaehak-gil, Chuncheon, Gangwon-do, 24341, Republic of Korea.
BMC Vet Res. 2024 Oct 26;20(1):490. doi: 10.1186/s12917-024-04335-x.
Chronic lymphoid leukemia (CLL) is a hematological disorder characterized by the clonal expansion of small mature lymphocytes that accumulate in the blood and bone marrow. CLL can arise from B-, T-, or natural killer cell clones. The cytological evaluation of blood smears is often the simplest and least invasive method for diagnosing lymphoid leukemia. Immunophenotyping is used to further subclassify the type of lymphoid leukemia.
A 15-year-old, 4.4-kg spayed female Shih Tzu was presented to the veterinary medical teaching hospital of Kangwon National University. Despite having a normal appetite and activity level, cervical and inguinal lymph node enlargement was noted on physical examination. Complete blood count revealed severe leukocytosis, severe lymphocytosis, and monocytosis. Splenomegaly, hepatomegaly, and lymph node enlargement were detected on radiographic and ultrasonographic examination. Immunophenotyping was performed using peripheral blood mononuclear cells (PBMCs). The majority of lymphocytes exhibited the following profiles: CD3CD79a (97.5%), CD4CD8 (98.6%), CD21CD79a (98.4%), CD34 (0.1%), CD45 (99.6%), major histocompatibility complex class II (99.5%), and CD14 (0.5%). Based on the immunophenotyping results, possible differentials considered included the following: the majority of lymphocytes may be natural killer (NK) cell clones, plasma cell clones, or show aberrant expression or loss of CD21 marker due to the neoplastic nature of the cells. Further flow cytometry was performed using antibodies against CD3, CD5, CD94, and granzyme B. The combined results indicated that the predominant lymphocyte subset in the PBMCs was CD3CD5CD21CD94granzyme B. To confirm monoclonality and exclude the aberrant loss of CD markers, a polymerase chain reaction for antigen receptor rearrangement (PARR) assay was conducted. The PARR assay, using DNA from blood and lymph node samples, showed B-cell monoclonality. Immunocytochemistry using PBMCs showed that the plasma cell marker Multiple Myeloma Oncogene 1 (MUM1) was not expressed. Therefore, the diagnosis was confirmed to be B-cell CLL.
Immunophenotyping can help subclassify the type of lymphoid leukemia; however, as tumor cells can show aberrant expression or loss of the CD21 marker, combining immunophenotyping with the PARR assay could yield a more accurate diagnosis.
慢性淋巴细胞白血病（CLL）是一种血液系统疾病，其特征是小成熟淋巴细胞克隆性扩增，这些细胞在血液和骨髓中积聚。CLL 可起源于 B 细胞、T 细胞或自然杀伤细胞克隆。血液涂片的细胞学评估通常是诊断淋巴细胞白血病最简单、最具侵袭性的方法。免疫表型分析用于进一步对淋巴细胞白血病进行分类。
一只 15 岁、体重 4.4 公斤的已绝育雌性西施犬被带到江原国立大学兽医教学医院就诊。尽管食欲和活动水平正常，但在体格检查时发现颈部和腹股沟淋巴结肿大。全血细胞计数显示严重的白细胞增多、严重的淋巴细胞增多和单核细胞增多。放射和超声检查发现脾肿大、肝肿大和淋巴结肿大。使用外周血单核细胞（PBMCs）进行免疫表型分析。大多数淋巴细胞表现出以下特征：CD3CD79a（97.5%）、CD4CD8（98.6%）、CD21CD79a（98.4%）、CD34（0.1%）、CD45（99.6%）、主要组织相容性复合体 II 类（99.5%）和 CD14（0.5%）。根据免疫表型分析结果，可能的鉴别诊断包括：大多数淋巴细胞可能是自然杀伤（NK）细胞克隆、浆细胞克隆，或由于细胞的肿瘤性质，表现出 CD21 标志物的异常表达或缺失。进一步使用针对 CD3、CD5、CD94 和颗粒酶 B 的抗体进行流式细胞术检查。联合结果表明，PBMCs 中的主要淋巴细胞亚群为 CD3CD5CD21CD94granzyme B。为了确认单克隆性并排除 CD 标志物的异常缺失，进行了抗原受体重排（PARR）聚合酶链反应检测。使用血液和淋巴结样本的 DNA 进行的 PARR 检测显示 B 细胞单克隆性。使用 PBMCs 进行的免疫细胞化学检测显示浆细胞瘤标志物多发性骨髓瘤癌基因 1（MUM1）未表达。因此，诊断确认为 B 细胞 CLL。
免疫表型分析可帮助对淋巴细胞白血病进行分类；然而，由于肿瘤细胞可能表现出 CD21 标志物的异常表达或缺失，因此将免疫表型分析与 PARR 检测相结合可能会得出更准确的诊断。
