Presence of in vivo-activated T-cells expressing HLA-DR molecules and IL-2 receptors in peripheral blood of patients with nasopharyngeal carcinoma

Cytokine and immunoglobulin production by PWM-stimulated peripheral and tumor-infiltrating lymphocytes of undifferentiated nasopharyngeal carcinoma (NPC) patients

BACKGROUND

Undifferentiated Nasopharyngeal Carcinoma (NPC) patients show a characteristic pattern of antibody responses to the Epstein-Barr virus (EBV) which is regularly associated with this tumor. However, no EBV-specific cytotoxic activity is detectable by the standard chromium-release assay at both peripheral and intratumoral levels. The mechanisms underlying this discrepancy between the humoral and cellular immune responses in NPC are still unknown, but might be related to an imbalance in immunoregulatory interleukin production. In this report, we investigated the ability of peripheral (PBL) and tumor- infiltrating (TIL) lymphocytes of undifferentiated NPC patients to produce in vitro three interleukins (IL-2, IL-6, IL-10) and three immunoglobulin isotypes (IgM, IgG, IgA).

METHODS

Lymphocytes from 17 patients and 17 controls were cultured in the presence of Pokeweed mitogen (PWM) for 12 days and their culture supernatants were tested for interleukins and immunoglobulins by specific enzyme-linked immunosorbent assays (ELISA). Data were analysed using Student's t-test and probability values below 5% were considered significant.

RESULTS

The data obtained indicated that TIL of NPC patients produced significantly more IL-2 (p = 0,0002), IL-10 (p = 0,020), IgM (p= 0,0003) and IgG (p < 0,0001) than their PBL. On the other hand, patients PBL produced significantly higher levels of IL-2 (p = 0,022), IL-10 (p = 0,016) and IgM (p = 0,004) than those of controls. No significant differences for IL-6 and IgA were observed.

CONCLUSION

Taken together, our data reinforce the possibility of an imbalance in immunoregulatory interleukin production in NPC patients. An increased ability to produce cytokines such as IL-10 may underlie the discrepancy between humoral and cellular immune responses characteristic of NPC.

The significance of soluble interleukin-2 receptor in monitoring disease relapse in patients with nasopharyngeal cancer

BACKGROUND

Soluble interleukin-2 receptor alpha (sIL-2R alpha) is a well-known indicator of T-cell activation noted to be increasing in nasopharyngeal cancer. However, the significance of sIL-2R alpha in monitoring disease relapse is unclear. This study was initiated to address this issue.

METHODS

Serum of 56 patients with NPC, which underwent either primary, salvage, or palliative treatments, from 1992 to 1993 at the Cancer Center, Veterans General Hospital-Taipei, were collected from our serum bank. According to their disease status at the time of study, at least two years after last treatments, the 56 patients were divided into four groups. The remission group represented those in remission at the time of study (n = 24). The metastasis group represented those with distant metastasis present at the time of study (n = 17). The recurrence group represented those with locoregional recurrence present at the time of study (n = 11). The combined group represented those with locoregional recurrence as well as distant metastasis (n = 4). The seral sIL-2R alpha concentrations of the 56 NPC patients were determined with enzyme-linked immunoabsorbent assay. The combined group was excluded in our statistical analysis. We performed statistical analysis on the differences of paired serum sIL-2R alpha concentrations between different periods of the diseases. The first analysis was on the differences of sIL-2R alpha concentrations between diagnosis and post-radiotherapy periods for 13 out of 24 patients in the remission group and 7 out of 11 patients in the recurrence group. The second analysis was on the differences of sIL-2R alpha concentration between follow-up before detection-of-relapse and after detection-of-relapse for 5 out of 17 patients in the metastasis group and six out of 11 patients in the recurrence group.

RESULTS

The first statistical analysis revealed no significant differences of sIL-2R alpha concentrations for the remission group (P = 0.946) and the recurrence group (P = 0.156) between diagnosis and post-radiotherapy periods. The second statistical analysis revealed no significant differences of sIL-2R alpha concentrations between before and after detection-of-relapse for the recurrence group, neither (P = 0.438). The results for the metastasis group were different. The sIL-2R alpha concentrations were shown to increase after the detection of metastasis for the 5 paired samples from the metastasis group, although the Wilcoxon signed ranks test on the differences only showed borderline significance (P = 0.063).

CONCLUSIONS

Our findings show that sIL-2R alpha would be of no value in monitoring the development of locoregional recurrence but might be useful in monitoring distant metastasis. Although our current limited data did not provide strong support for the role of sIL-2R alpha in monitoring metastasis, it might be delineated in the future by collecting more data.

Emergence of non-major-histocompatibility-complex-restricted lytic CD8+ cells in the blood of nasopharyngeal carcinoma patients

A large body of evidence has suggested that the Epstein-Barr virus (EBV) is strongly associated with undifferentiated nasopharyngeal carcinoma. Immunologically, this neoplasia is characterized by the absence of anti-EBV circulating cytotoxic T lymphocytes (CTL), despite a high number of peripheral activated CD8+ cells, as previously determined in our laboratory. In order to determine whether the absence of anti-EBV CTL is related to a reduced number of circulating anti-EBV effector cells, we attempted to expand these hypothetical specific T cells by induction of proliferation with recombinant interleukin-2 (rIL-2), in the, absence of any stimulator cells. Optimal conditions for stimulation of peripheral blood lymphocytes (PBL) of nasopharyngeal patients were obtained with 100 U/ml rIL-2 during 10 days of culture. PBL treated with rIL-2 induced a selective expansion of CD8+ cells and generated a potent cytotoxicity towards autologous or HLA-compatible lymphoblastoid cell lines, used as target cells in a chromium-release thest. However, this cytolysis was non-MHC-restricted, since, the monoclonal antibodies anti-(HLA class I) and anti-(HLA class II) were inefficient in inhibiting this cytotoxicity. Interestingly, purified CD8+ cells acquired the capacity for non-MHC-restricted cytolysis.

Suppressed cellular immunity in patients with nasopharyngeal carcinoma

The subsets and functions of lymphocytes were investigated in patients with nasopharyngeal carcinoma (NPC). The patients were divided into two groups comprising tumor-bearing patients and those in remission. There was no difference in the proportion of T cells among tumor-bearing, remission and healthy control groups. The percentages of inducer/helper T cells and natural killer cells were smaller in the tumor-bearing group than in the control group whereas the percentage of suppressor T cells was greater in the tumor-bearing group. Phytohemagglutinin-stimulated blastogenesis was markedly suppressed in the tumor-bearing group. The responsiveness to interleukin-2 of blastogenesis and of natural killer and lymphokine-activated killer activities was lowered in the tumor-bearing group. These parameters in the remission group were intermediate between those of the tumor-bearing and control groups. These results suggest that cellular immunity is suppressed in patients with NPC and that the suppressed condition still remains even in remission. Immunotherapy is considered to be indispensable for the proper treatment of NPC.

Selective homing of phenotypically lytic cells within nasopharyngeal carcinoma biopsies: numerous CD8- and CD16-positive cells in the tumor

We present a comparative analysis of cell-mediated immunity between circulating lymphocytes and tumor-infiltrating lymphocytes (TIL) from patients with nasopharyngeal carcinoma (NPC). Phenotypic analysis using a panel of monoclonal antibodies (MAbs) to define lymphocytic subsets has revealed a selective homing of phenotypically lytic cells such as CD8- and CD16-positive cells, but a low percentage of macrophages when compared to PBL of NPC patients. Also, PBL and TIL contain an equivalent percentage of activated T-lymphocytes expressing HLA-DR molecules and IL-2 receptors. Functionally, TIL exhibit an abolished NK-cell activity and concomitant decrease of proliferative response to phytohemagglutinin (PHA) and concanavalin A (ConA) stimulation when compared with PBL.

Local immune reaction in nasopharyngeal carcinoma, with special reference to its prognostic evaluation

A study of the tumor-host interaction was conducted in 30 patients with nasopharyngeal carcinoma (NPC). The local immune reaction was investigated by an immunoperoxidase technique using monoclonal antibodies. Eighteen patients who were clinically suspected to have NPC, but finally proved otherwise, served as controls. There was a significant difference between the number of NPC patients with interleukin-2 receptor (IL-2R)-positive cells (activated T lymphocytes) in the stroma compared with the control. IL-2R positive cells were found in 67% of NPC patients but in only 22% of controls (P less than 0.01). There was a greater infiltration of T lymphocytes in patients with a good outcome compared with patients with a poor outcome. This trend was observed in both the parenchyma (60.2 versus 29.4 x 10(4) cells/mm2) and the stroma (74.7 versus 44.8 x 10(4) cells/mm2). The levels of Leu-3 positive cells (helper/inducer) in the NPC parenchyma were inversely correlated to the extent of the primary tumor, but there was no correlation in the stroma. These findings demonstrate that a local host-immune reaction does exist and may be a useful prognostic indicator for NPC patients.

High interferon titer and defective NK-cell activity in the circulation of nasopharyngeal carcinoma patients

The interferon (IFN) activity of sera from 19 patients with nasopharyngeal carcinoma (NPC) was determined by the plaque-reduction assay with vesicular stomatitis virus (VSV) in HeLa cells and compared to that of sera from matched healthy controls. High titers of interferon were detected in the sera of the NPC patients with a geometric mean titer (GMT) of 43 +/- 25 U/ml. The interferon activity of the patients' sera was acid- and heat-labile (pH = 2 and 56 degrees C for 1 hr) and could be neutralized by a goat antiserum to human IFN-gamma. Interferon titers of the patients, in contrast, to normal controls, were not correlated with natural killer (NK) activity which was abnormally low in the NPC patients. On the other hand, a high percentage of circulating cells co-expressing the LGL marker (HNK-I) and the OKT8 antigen was detected in parallel with high IFN levels in NPC patients.