Autologous stem-cell transplantation restores the functional properties of CD14+CD16+ monocytes in patients with myeloma and lymphoma

The metabolic profile of reconstituting T-cells, NK-cells, and monocytes following autologous stem cell transplantation and its impact on outcome

Previous studies indicated a role of the reconstituting immune system for disease outcome upon high-dose chemotherapy (HDCT) and autologous stem cell transplantation (auto-SCT) in multiple myeloma (MM) and lymphoma patients. Since immune cell metabolism and function are closely interconnected, we used flow-cytometry techniques to analyze key components and functions of the metabolic machinery in reconstituting immune cells upon HDCT/auto-SCT. We observed increased proliferative activity and an upregulation of the glycolytic and fatty acid oxidation (FAO) machinery in immune cells during engraftment. Metabolic activation was more pronounced in T-cells of advanced differentiation stages, in CD56^bright NK-cells, and CD14⁺⁺CD16⁺ intermediate monocytes. Next, we investigated a potential correlation between the immune cells’ metabolic profile and early progression or relapse in lymphoma patients within the first twelve months following auto-SCT. Here, persistently increased metabolic parameters correlated with a rather poor disease course. Taken together, reconstituting immune cells display an upregulated bioenergetic machinery following auto-SCT. Interestingly, a persistently enhanced metabolic immune cell phenotype correlated with reduced PFS. However, it remains to be elucidated, if the clinical data can be confirmed within a larger set of patients and if residual malignant cells not detected by conventional means possibly caused the metabolic activation.

Pattern of human monocyte subpopulations in health and disease

Monocytes are important cells of the innate system. They are a heterogeneous type of cells consisting of phenotypically and functionally distinct subpopulations, which play a specific role in the control, development and escalation of the immunological processes. Based on the expression of superficial CD14 and CD16 in flow cytometry, they can be divided into three subsets: classical, intermediate and non-classical. Variation in the levels of human monocyte subsets in the blood can be observed in patients in numerous pathological states, such as infections, cardiovascular and inflammatory diseases, cancer and autoimmune diseases. The aim of this review is to summarize current knowledge of human monocyte subsets and their significance in homeostasis and in pathological conditions.

Phagocyte function decreases after high-dose treatment with melphalan and autologous stem cell transplantation in patients with multiple myeloma

High-dose melphalan with autologous hematopoietic stem cell transplantation (ASCT) is the standard of care for younger patients with newly diagnosed multiple myeloma and is aimed at achieving as deep and complete a response as possible after various combinations of induction therapy. However, it is frequently associated with infectious complications. This study investigated the effects of high-dose treatment with autologous stem cell support on patients' innate immunity, with a focus on subpopulations and functioning of recently released polymorphonuclear leukocytes (PMNs) and monocytes in peripheral blood. Flow cytometry-based analysis was used to measure the degree of PMN maturation and activation, before and after ASCT and compared with healthy controls. After high-dose treatment and ASCT, a smaller proportion of patients' PMNs had the capacity for oxidative burst. Moreover, patients' PMNs, both before and after ASCT, had a reduced capacity for phagocytosis. Eosinophils, which recently have been suggested to play a role in promoting malignant plasma cell proliferation, were markedly reduced after ASCT, with slow regeneration. HLA-DR expression by monocytes was significantly depressed after ASCT, a characteristic often attributed to monocytic myeloid-derived suppressor cells. Our results suggest that several aspects of phagocytic function are impaired for at least 20 days after ASCT.

Low Counts of Plasmacytoid Dendritic Cells after Engraftment Are Associated with High Early Mortality after Allogeneic Stem Cell Transplantation

Dendritic cells (DCs) are antigen-presenting cells that drive immune responses and tolerance and are divided in different subsets: myeloid DCs (mDCs: lineage-; HLA-DR+, 11c+), plasmacytoid dendritic cells (pDCs: HLA-DR+, CD123+), and monocyte-derived DCs (moDC: lineage-, 11c+, 16+). After hematopoietic stem cell transplantation (HSCT), low DC counts in the recipients' peripheral blood (PB) have been associated with worse outcomes, but the relevance of DC graft content remains unclear, and there are few data in the setting of unrelated donor HSCT. We evaluated the DC graft content and monitored DC recovery in PB from 111 HSCT recipients (median age, 17 years; range 1 to 74), who received bone marrow (46%), umbilical cord blood (32%), or PB (22%) from unrelated (81%) or related donors (19%). In 86 patients with sustained allogeneic recovery, patients with higher counts of all DC subsets (pDC, mDC, and moDC) 3 weeks after engraftment had lower incidence of nonrelapse mortality (NMR) and acute graft-versus-host disease (aGVHD) and better survival. pDC counts were associated with more striking results: patients with higher pDC counts had much lower incidences of NRM (3% versus 47%, P < .0001), lower incidence of aGVHD (24% versus 67%, P < .0001), and better overall survival (92% versus 45%, P < .0001). In contrast, higher pDC counts in the graft was associated with an increased risk of aGVHD (55% versus 26%, P = .02). Our results indicate that DC counts are closely correlated with HSCT outcomes and warrant further prospective evaluation and possible early therapeutic interventions to ameliorate severe aGVHD and decrease mortality.

Spontaneous decrease of CD14 cell surface expression in human peripheral blood monocytes ex vivo

In the continuous presence of bacterial lipopolysaccharide (LPS), the membrane-bound LPS receptor, CD14, exhibits a biphasic pattern of surface expression in monocytes ex vivo; an initial increase is followed by a later decrease. In the presence of LPS, ex vivo changes in monocytic CD14 cell surface expression have been consistently interpreted as the direct result of LPS exposure. There has been little consideration for the possibility of additional cell culture effects. Here, an experiment is presented to dissect the differences between LPS effects and cell culture effects on monocytic CD14 cell surface expression ex vivo. The results show that in monocytes from diluted whole blood cultures, CD14 surface expression is induced in LPS-treated samples but decreased in untreated samples. These observations suggest that the previously observed biphasic surface expression pattern of CD14 in long-term LPS-treated monocytes may be the result of a superposition of LPS-induced expression and spontaneous disappearance of CD14 from the plasma membrane. Further, these results illustrate the importance of taking cell culture conditions into account when analyzing monocyte expression of CD14.

Defective infiltration of natural killer cells in MICA/B-positive renal cell carcinoma involves beta(2)-integrin-mediated interaction

We have explored MICA/B expression and its relationship with innate inflammatory infiltrate in renal cell carcinoma (RCC). The expression of MICA/B, CD16, CD56, and CD68 in 140 RCC lesions contained in a tissue microarray (TMA) was investigated by immunohistochemistry. MICA/B gene and protein expressions in Caki-1 cells were analyzed by reverse transcription-polymerase chain reaction and flow cytometry, respectively. Natural killer (NK) cells were studied by flow cytometry. All the RCC lesions (n = 140) were MICA/B-positive. MICA/B was mainly expressed in the cytoplasm of tumor cells, whereas stromal cells were negative. Renal cell carcinoma lesions showed low NK cell infiltration, although they were rich in CD16(+)CD56(-) cells, strongly resembling macrophages. CD16(+) macrophage infiltration was more frequently detectable in metastatic lesions compared with primary tumors (P = .0223) and was associated with poor RCC differentiation (P = .007). To investigate mechanisms potentially underlying the lack of NK cells infiltration into MICA/B-positive RCC lesions, we used Caki-1 RCC cells. Caki-1 expressed MICA and MICB genes. However, MICA protein was not detectable in Caki-1 cells, whereas MICB protein was detectable in their cytoplasm and on the cell membrane. Coculture of peripheral blood mononuclear cells with Caki-1, K562, HCT116, respectively, resulted in CD56(+)CD16(+) NK cells deletion without affecting CD56(+)/CD16(-) NK subset and immature NK cells generated in vitro from CD34(+) cells. Natural killer cell apoptosis seemed to be preferentially triggered by cancer cells because HLA-A0201(+) NK cells were only marginally affected by allogeneic HLA-A0201(-) peripheral blood mononuclear cells. Caki-1 cell-mediated NK cell apoptosis was reduced by an anti-beta(2)-integrin (CD18) monoclonal antibody but was NKG2D-, granule exocytosis-, and caspase-independent.

Significant alterations in peripheral blood lymphocyte subsets in patients with somatoform disorder

OBJECTIVE

Previous studies have suggested that somatoform disorders (SFD) might be associated with changes in the function of the central and autonomic nervous systems. The aim of this study was to examine the possible immunological differences between SFD and healthy controls.

METHODS

Twenty-four patients with SFD and 13 healthy individuals completed the psychological questionnaires to assess symptom reporting [Symptom Checklist-90 Revised (SCL-90-R)] and to diagnose for SFD [Screening for Somatoform Symptoms scale (SOMS-scale)]. Participants also provided a blood sample taken in the morning, which was analysed with an automated cell counter to determine the number of leucocytes per μl and with flow cytometry to determine lymphocyte subsets.

RESULTS

With the exception of a higher T4/T8 ratio in the patient group, which was mainly because of lower CD8 counts, there were no significant differences in the absolute number of lymphocytes (subsets) between patients with SFD and healthy subjects. A positive correlation between B-lymphocyte subsets (CD19+CD22+, CD19+CD5+, CD19+CD3-) to all scales of the SCL-90-R, except somatisation, were found in SFD. Additionally, a positive correlation was found in SFD between CD14+CD16+ monocytes and somatisation (0.573) on the SCL-90-R scale.

CONCLUSION

These data indicate that patients with SFD have an enhanced humoral immunity as shown by increased B-cell numbers and furthermore an elevated T4/T8 ratio because of lower CD8 suppressor cells. Further studies will be required to determine whether these alterations in lymphocyte subsets are directly involved in the pathophysiology of SFD.

Distinct reconstitution of neutrophil functions after allogeneic peripheral blood stem cell transplantation

PURPOSE

The study investigated in detail neutrophil functions shortly after allogeneic peripheral blood stem cell transplantation (PBSCT).

METHODS

Different functions of neutrophils in 14 patients who received allogeneic PBSCT were investigated. The migratory capacity as well as the ability to induce oxidative burst following stimulation with either Phorbol-12-myristate-13-acetate (PMA), the chemotactic peptide N-formyl-Met-Leu-Phe (f-MLP) or opsonized Escherichia coli was analysed after engraftment (between day +30 and +40) and compared with the results obtained from healthy volunteers.

RESULTS

There are no differences in terms of the migratory capacity (P = 0.17), as well as regarding the oxidative burst after incubation with PMA (P = 0.08) or f-MLP (P = 0.06), compared with healthy men. In contrast, the capacity of neutrophils to induce oxidative burst following stimulation with E. coli is highly impaired (P = 0.0001) in patients shortly after engraftment.

CONCLUSION

The recovery of neutrophils after allogeneic PBSCT is not only influenced by the varying time of engraftment, but also represents a process that differs in distinct biological functions compared to normal granulopoieses.

Correlation of residual leukocyte subsets with neutropenic fever during severe leukopenia after high-dose chemotherapy and autologous stem cell transplantation

BACKGROUND

High-dose chemotherapy with autologous stem cell transplantation is the standard treatment of eligible patients with multiple myeloma. However, this treatment is associated with a substantial risk of infectious complications during leukopenia. The aim of our pilot study was to determine the residual leukocyte subsets during severe cytopenia after high-dose melphalan and to correlate this with the occurrence of neutropenic fever.

METHODS

Residual leukocyte subsets in the peripheral blood on days 4-7 following autologous stem cell transplantation were analyzed by three-color flow cytometry in 20 patients with multiple myeloma. In addition, we determined the number of T cells that were transfused with the autografts.

RESULTS

Absolute numbers of lymphocytes (mean 25/microL) and monocytes (mean 4/microL) were strongly reduced but rather constant during the period of severe neutropenia. Neutrophil engraftment and duration of neutropenia were very similar in patients with and without neutropenic fever. Low absolute lymphocyte counts and absolute CD4+ T-cell counts on days 4-7 after stem cell transplantation correlated with neutropenic fever. Furthermore, T-cell numbers in the autologous stem cell grafts that the patients received were significantly lower in patients with neutropenic fever.

DISCUSSION

These observations suggest that the number of T cells, and in particular CD4+ T cells, in the blood during severe cytopenia is playing a role in defense of infection. T-cell numbers in the graft could provide a predictive factor for the risk of infection in the post-transplant period. However, this needs to be confirmed in a larger study.