The aim of this project was to compare dual and tri-colour reagents for lymphocyte immunophenotyping. A total of 37 patient and normal specimens were immunophenotyped concurrently with the following mean values (% dual vs tri-colour): CD3 (69.4 vs 68.3) CD4 (24.0 vs 24.2) and CD19 (13.9 vs 12.6). A comparison of the results obtained using the paired t test showed that there were no significant differences for cells expressing CD3, CD4 and CD19. However, there was a significant difference in the NK (18.3 vs 16.3) cell component. A major advantage in using 3 colour immunophenotyping is the ability to analyse specimens that cannot be analysed using dual colour reagents due to debris or contamination of the gate with non-lymphocytic cells.
A case of chronic mucocutaneous candidiasis in a Malaysian child who subsequently developed disseminated tuberculosis and toxoplasmosis is described. The phenotype of her peripheral blood mononuclear cells showed discordance for her T cell markers. The presence of a subpopulation of CD2-/CD3+ mononuclear cells leading to an immunodeficiency state is consistent with failure of activation of CD2-mediated alternative pathway resulting in immunodeficiency. Such abnormal CD2-/CD3+ subpopulations have been described in lepromatous leprosy and foetal abortuses.
The pathological significance of the mechanisms of tumour immune-evasion and/or immunosuppression, such as loss of T cell signalling and increase in regulatory T cells (T(regs)), has not been well established in the nasopharyngeal carcinoma (NPC) microenvironment. To evaluate the T(reg) immunophenotypes in tumour-infiltrating lymphocytes (TILs), we performed a double-enzymatic immunostaining for detection of forkhead box P3 (FoxP3) and other markers including CD4, CD8, and CD25 on 64 NPC and 36 non-malignant nasopharyngeal (NP) paraffin-embedded tissues. Expression of CD3 zeta and CD3 epsilon was also determined. The prevalence of CD4(+)FoxP3(+) cells in CD4(+) T cells and the ratio of FoxP3(+)/CD8(+) were increased significantly in NPC compared with those in NP tissues (P < 0.001 and P = 0.025 respectively). Moreover, the ratio of FoxP3(+)/CD25(+)FoxP3(-) in NPC was significantly lower than that in NP tissues (P = 0.005), suggesting an imbalance favouring activated phenotype of T cells in NPC. A significant negative correlation between the abundance of FoxP3(+) and CD25(+)FoxP3(-) cells (P < 0.001) was also identified. When histological types of NPC were considered, a lower ratio of FoxP3(+)/CD25(+)FoxP3(-) was found in non-keratinizing and undifferentiated carcinomas. Increased CD4(+)FoxP3(+)/CD4(+) proportion and FoxP3(+)/CD8(+) ratio were associated with keratinizing squamous cell carcinoma. A reduced expression of CD3 zeta in TILs was found in 20.6% of the NPC tissues but none of the NP tissues. These data provide evidence for the imbalances of T(reg) and effector T cell phenotypes and down-regulation of signal-transducing molecules in TILs, supporting their role in suppression of immune response and immune evasion of NPC.