Immunohistochemical assessment of splenic lymphocyte and macrophage subpopulations in patients with gastric cancer

Effect of Splenectomy Combined with Resection for Gastric Carcinoma on Patient Prognosis

BACKGROUND For patients with stage IV gastric cancer, it is unclear whether splenectomy combined with palliative surgery is needed to reduce tumor load and relieve symptoms. The objective of the present study was to investigate the effect of splenectomy combined with palliative resection for stage IV gastric carcinoma on immunological dysfunction and patient prognosis. MATERIAL AND METHODS We retrospectively analyzed medical records of 106 stage IV gastric cancer patients who underwent palliative surgery; of these, 49 patients were treated with palliative resection for gastric carcinoma combined with splenectomy, while the other 57 patients retained their spleens. The immunologic function and prognosis in these 2 groups were examined and compared. RESULTS The immune function of patients in the group that retained their spleens was better later in the postoperative course than in the resection group. The groups did not show statistically significant differences in postoperative infectious complications, median survival time, and survival rate; however, the average postoperative hospitalization time of patients in the retained group was significantly shorter. CONCLUSIONS Splenectomy combined with gastric cancer resection did not improve the prognosis of the patients; patients who retained their spleens had faster recovery and improved immune function. However, whether retaining the spleen is an independent factor improving the prognosis needs further investigation.

Characterization of immune responses in gastric cancer patients: a possible impact of H. pylori to polarize a tumor-specific type 1 response?

Recently, we were able to show that Helicobacter pylori-positive gastric cancer (GC) patients have a significantly better survival after the complete resection of their tumor compared to H. pylori-negative GC patients. H. pylori is known to polarize an immune response towards a type 1 cytokine profile and tumor-specific type 1 cytokine responses are associated with protection from tumor challenge and T-cell-mediated tumor regression. Therefore, we hypothesized that the improved survival in H. pylori-positive patients may be secondary to the induction of a GC-specific type 1 T cell response. To characterize the anti-tumor immune response in GC patients we analyzed tumor-infiltrating lymphocytes (TIL) isolated from primary tumors. The CD3+ T cell population contained 50% CD4+ (range 0.4-81%) and 39% CD8+ cells (range 22-53%). The number of B cells (CD19+, P = 0.03) was significantly increased and the number of T cells (CD3+, P = 0.02) significantly decreased in intestinal compared to diffuse type of tumors. Four tumor cell lines were established from primary GCs and three from lymph node metastases. T cell cultures were established from isolated TIL from four H. pylori-positive and one H. pylori-negative GC patients and tested for tumor-specific cytokine secretion. Eight of ten T cell cultures derived from H. pylori-positive patients secreted both IFN-gamma and IL-5 after restimulation with autologous tumor cells. The only tumor-specific TIL line expressing a dominant IL-5 response was derived from an H. pylori-negative patient.

Augumentation of splenic antitumor immunity by local immunotherapy in gastric cancer patients

We previously reported that the antitumor effect of OK-432, a streptococcal preparation, was markedly augmented when this agent was injected into tumors together with fibrinogen. In order to elucidate the effect of this treatment on the spleen, we assessed splenic function in gastric cancer patients receiving preoperative local immunotherapy with OK-432 and fibrinogen. Immunohistochemical studies of the spleen at 7 days after intratumoral injection therapy revealed numerous macrophages phagocytizing OK-432 in the splenic sinuses. Phenotypic analysis of splenocytes by flow cytometry revealed an increase in the CD4/CD8 ratio and in the expression of HLA-DR, CD25, and Leu M3 by splenic T cells of the patients treated with OK-432 plus fibrinogen when compared to patients treated with OK-432 alone or untreated patients. Splenic T cells from patients treated with OK-432 plus fibrinogen showed significantly higher cytotoxicity against Daudi and K562 cells than T cells from control patients (p < 0.05), and culture of these splenic T cells with recombinant IL-2 induced the expansion of lymphokine-activated killer cells. These results demonstrate that local immunotherapy with a mixture of OK-432 and fibrinogen effectively augumented splenic antitumor immunity in gastric cancer patients.

Spontaneous antibody-secreting cells in the stomach of gastric cancer patients

The gastric mucosa has been regarded as an active site of humoral immunity since the discovery of Helicobacter pylori. The present study was conducted to determine the in vivo activity of gastric B cells in 53 gastric cancer patients. B-cell activity was measured by protein-A plaque assay, in which IgA-, IgM-, and IgG-plaque-forming cells (PFC) were counted. The number of PFC was associated with the stage of cancer, but the response of lymphocytes in a non-tumorous area (NML) and tumor-infiltrating lymphocytes (TIL) differed. PFC in both sites were decreased compared to n0 cancer in n1 lymph node metastasis-positive cancer, while only NML showed raised PFC in n2 + (P < 0.05, vs TIL). Cancer cells penetrating the submucosa caused the PFC of TIL (but not of NML) to decrease. Invasion of the intratumor capillary (V) or lymphatic (Ly) vessels also caused PFC to change, showing differences of Ig class; there was a decrease of PFC in V2 (IgG- and IgM-PFC) and in Ly2 (all Ig-PFC). IgA-PFC in Ly1 differed in TIL (decrease of PFC) and NML (increase). PFC also differed in TIL and NML in cancer cells, as follows: TIL < NML in tubular and poorly differentiated adenocarcinoma and TIL > NML in papillary and signet ring cell adenocarcinoma. Changes in lymph node (LNL) and blood lymphocytes were similar to those in gastric PFC whose IgA value was 10 times as much as that of LNL. The 5-year survival rate was significantly better in patients with lower rather than higher PFC such as 89% vs 68%. Gastric B cells thus appear to be active and to reflect gastric mucosal immunity.

Two-color flow cytometric analysis of splenic lymphocyte subpopulations in patients with gastric cancer

Lymphocyte subpopulations of the spleen were assayed in 26 patients with gastric cancer and 5 patients with benign disease using two-color flow cytometric analysis. The ratio of Leu 2a+.Leu 15+ cells, or suppressor T cells, in the gastric cancer patients was about 6 per cent, being higher than that in the patients with benign disease (p less than 0.05). There were fewer Leu 7+.Leu 11- cells, or natural killer-NK-cells, in the gastric cancer patients in stage III or IV than in those with stages I or II (p less than 0.05). The ratio of Leu 3a+.Leu 8- cells, or helper T cells, in the stage IV patients accounted for about 15 per cent of the splenic lymphocytes, which was less than that seen in the patients in stages I or II (p less than 0.05). The ratio of Leu 2a+.Leu 15- cells, or cytotoxic T cells, was approximately twice that of suppressor T cells. The pre-operative administration of lentinan plus OK-432 increased the ratio of Leu 4+.HLA-DR+ cells, or activated T cells, and cytotoxic T cells (p less than 0.05 and p less than 0.01, respectively). The above results suggest that lymphocyte subpopulations in the spleen may have more immunosuppressive potential in proportion with the stage of gastric cancer, but that this reduced immune state may be altered when lentinan and OK-432 are given to these patients.