原位杂交对胃粘膜相关组织淋巴瘤的免疫球蛋白轻链的检测

目的 评价mRNA原位杂交方法检测免疫球蛋白轻链限制性在胃粘膜相关组织淋巴瘤诊断中的应用价值。方法 用非同位素标记寡核苷酸mRNA探针原位杂交方法检测27例原发怀胃粘膜相关淋巴瘤和5例慢性胃炎,对其中的肿瘤细胞、淋巴细胞及浆细胞的免疫球蛋白κ和λ轻链的比例进行分析,以确定肿瘤细胞的轻链限制性及浆细胞的单克隆性。结果 27例原发性胃粘膜相关淋巴瘤中有10例出现轻链限制性（37％）,其中5例（5／9）为低度恶性病例,5例（5／18,28％）为高度恶性病例,单克隆性的浆细胞只在低度恶性病例中检出。慢性胃炎标本及肿瘤旁组织中未检测出轻链限制性。结论 mRNA原位杂交方法检测轻链限制性是诊断胃淋巴瘤的一个有用工具,低度恶性淋巴瘤中单克隆性浆细胞的存在,可作为诊断早期胃粘膜相关淋巴瘤的依据之一。

Detection of Immunoglobulin light chain restriction of mucosa-associated lymphoid tissue type gastric lymphoma using mRNA in situ hybridization

OBJECTIVE: To evaluate the usefulness of in situ hybridization for Immunoglobulin kappa and lambda light chain mRNA to detect light chain restriction in the diagnosis of primary gastric lymphoma (PGL) of mucosa-associated lymphoid tissue (MALT) type. METHODS: Twenty-seven cases of PGL of MALT type and 5 cases of gastritis were analyzed using in situ hybridization with fluorescent isothiocyanate (FITC)-labeled oligonucleotide probes for kappa and lambda light chain mRNA. The kappa:lambda ratios of tumor cells, lymphocytes and plasma cells were analyzed to detect light chain restriction and clonal plasma cells. RESULTS: Light chain restriction was found in 10 of 27 (37%) cases of PGL cases (in 5/9 low grade and 5/18 in high grade). Clonal plasma cells were detected in low grade but not in high-grade cases. No light chain restriction was found in gastritis specimens, the adjacent tissue of tumors or the distant stomach mucosa in lymphoma cases. CONCLUSIONS: The detection of clonality using mRNA in situ hybridization could be a helpful diagnostic tool for gastric lymphoma. The presence of clonal plasma cells can be a marker of the early lesion of low-grade PGL.