Effect of ranitidine on soluble interleukin 2 receptors and CD8 molecules in surgical patients

Histamine receptor 2 blockade selectively impacts B and T cells in healthy subjects

Histamine receptor 2 (H2R) blockade is commonly used in patients with gastric, duodenal ulcers or gastroesophageal reflux disease. Beyond the gastrointestinal tract, H2R is expressed by multiple immune cells, yet little is known about the immunomodulatory effects of such treatment. Clinical reports have associated H2R blockade with leukopenia, neutropenia, and myelosuppression, and has been shown to provide clinical benefit in certain cancer settings. To systematically assess effects of H2R blockade on key immune parameters, a single-center, single-arm clinical study was conducted in 29 healthy subjects. Subjects received daily high dose ranitidine for 6 weeks. Peripheral blood immunophenotyping and mediator analysis were performed at baseline, 3 and 6 weeks into treatment, and 12 weeks after treatment cessation. Ranitidine was well-tolerated, and no drug related adverse events were observed. Ranitidine had no effect on number of neutrophils, basophils or eosinophils. However, ranitidine decreased numbers of B cells and IL-2Rα (CD25) expressing T cells that remained lower even after treatment cessation. Reduced serum levels of IL-2 were also observed and remained low after treatment. These observations highlight a previously unrecognised immunomodulatory sustained impact of H2R blockade. Therefore, the immune impacts of H2R blockade may require greater consideration in the context of vaccination and immunotherapy.

Circulating T-lymphocyte activation in patients with variant angina

BACKGROUND

Both experimental and pathological studies suggest that immune response and inflammation may play an important role in the pathogenesis of coronary spasm.

DESIGN

To elucidate the role of systemic immune and inflammatory responses in the pathogenesis of coronary spasm, we studied circulating T-lymphocyte activation in variant angina patients (VAPs), stable effort angina patients (EAPs) and in control participants.

METHODS

Twenty documented VAPs, 13 EAPs and 20 control participants were studied. To evaluate T-lymphocyte activation, T-lymphocyte surface antigen expression, including CD3, CD4, CD8 and HLA-DR, was measured by two-colour flow cytometric analysis. Serum-soluble interleukin-2 receptor (sIL-2R) and C-reactive protein (CRP) were also measured by enzyme-linked immunosorbent assay. We restudied 10 of the VAPs to investigate the relationship between the disease activity of variant angina and T-lymphocyte activation.

RESULTS

The percentage of CD3+/DR+ T-lymphocytes in VAPs (14.8%) was significantly higher than in EAPs (10.7%, P < 0.05) and control participants (9.7%, P < 0.005); however, levels of sIL-2R were the same among the three groups. Levels of CRP were within normal range in all VAPs. The percentage of CD8+/DR+ T-lymphocytes was significantly higher in VAPs (9.5%, P < 0.005) than in EAPs (5.5%) and control participants (5.9%), whereas the percentage of CD4+/DR+ T-lymphocytes was similar among the three groups. The percentage of activated T-lymphocytes in VAPs was unchanged during the follow-up period (mean intervals, 10 months).

CONCLUSIONS

These results indicate that the chronic activation of T-lymphocytes, especially CD8+ T-lymphocytes, may be involved in the pathogenesis of coronary spasm.

Randomised comparison of leucocyte-depleted versus buffy-coat-poor blood transfusion and complications after colorectal surgery

BACKGROUND

Allogeneic blood transfusion is associated with an increased frequency of postoperative infection. We studied whether such events can be avoided by the intraoperative and postoperative use of leucocyte-depleted blood.

METHODS

589 consecutive patients scheduled for elective colorectal surgery were randomised to receive buffy-coat poor (n = 299) or filtered leucocyte-depleted red-cells (n = 290) when transfusion was indicated. 260 patients actually received blood transfusion. Three patients were excluded from analysis.

FINDINGS

The 142 patients randomised to and transfused with buffy-coat-poor blood had a significantly higher frequency of wound infections and intra-abdominal abscesses than the 155 patients who were allocated to this group but who were not transfused. (12 vs 1%, p < 0.0001) and (5 vs 0%, p = 0.005), respectively. Those receiving buffy-coat-poor blood also had a significantly higher frequency of wound infections and intra-abdominal abscesses than the 118 randomised to and receiving leucocyte-depleted blood (12 vs 0%, p < 0.0001) and (5 vs 0%, p = 0.017), respectively. Postoperative pneumonia occurred at a significantly higher rate in patients receiving buffy-coat-poor blood: 23 versus 3% in non-transfused patients (p < 0.0001), and 23 versus 3% in patients transfused with leucocyte-depleted blood (p < 0.001). The mortality rate between the groups was not statistically different.

INTERPRETATION

Our data suggests that the association between allogeneic blood transfusion and postoperative infection is limited to allogeneic blood products that are not adequately depleted of immunosuppressive leucocytes. This undesirable effect can be reduced by leucocyte depletion with high-efficiency filters.

A randomized controlled study of the effect of bedside leucocyte depletion on the immunosuppressive effect of whole blood transfusion in patients undergoing elective colorectal surgery

In a randomized study the effect of whole blood transfusion versus bedside leucocyte-depleted blood transfusion on lymphocyte proliferation, CD4+:CD8+ ratio, and levels of soluble interleukin 2 receptor (sIL-2R) and interleukin (IL) 6, as well as on the development of postoperative wound infection and intra-abdominal abscess, was assessed in 60 patients undergoing elective colorectal surgery. Transfusion with whole blood induced a significant decrease in lymphocyte proliferation and CD4+ :CD8+ ratio (P < 0.01) as well as a significant increase in sIL-2R and IL-6 levels (P < 0.01). Furthermore, transfusion with whole blood was accompanied by a significant increase in postoperative infectious complications (P < 0.01). In patients transfused with leucocyte-depleted blood only slight and transient changes were observed, which were not significantly different from those observed in non-transfused patients.

Histamine-2 receptor antagonists as immunomodulators: new therapeutic views?

Considerable evidence has emerged to suggest that histamine participates in the regulation of the inflammatory response, immune reaction, coagulation cascade, and cardiovascular function. Furthermore, histamine may play a major role in the growth of normal and malignant tissue as a regulator of proliferation and angiogenesis. Specific histamine receptors have been identified on the surface of bone marrow cells, immune competent cells, endothelial cells, fibroblasts, and also on malignant cells. This has prompted research in regulation by specific histamine receptor agonists and antagonists. Results from such studies are currently accumulating and suggest that the histamine-2 receptor antagonists have potential beneficial effects in the treatment of certain malignant, autoimmune and skin diseases, either alone or in combination with other drugs. The beneficial effect of histamine-2 receptor antagonists as adjuvant single drugs to reduce trauma-, blood transfusion- and sepsis-induced immunosuppression has led to research in combined treatment regimens in major surgery, particularly, of patients operated on for malignant diseases.