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K R Meehan

Publications and source records attributed to K R Meehan.

At least 19 recordsLinked to original sources
PubMed2006

Ex vivo expansion of non-MHC-restricted cytotoxic effector cells as adoptive immunotherapy for myeloma.

BACKGROUND: PBMC can be expanded ex vivo into aggressive cytotoxic effector cells (CEC) comprising T, NK and NKT cells. We identified the phenotype, cytotoxicity and mechanisms of killing of these CEC. METHODS: CY- and G-CSF-mobilized PBMC from myeloma patients were placed in Aim-V serum-free medium, IL-2 (50 IU/mL) and OKT-3 (50 ng/mL). Cytotoxicity was evaluated by selectively blocking the TCR, MHC class I or NKG2D receptor. RESULTS: The CEC expanded three-fold by day 7 and aggressively lysed myeloma cells (41.9%) compared with day 0 (4%; P=0.012). CD8+ CD56+ NKT cells performed the majority of lysis. The CD8+ cells greatly increased NKG2D expression during culture (P=0.005). Cytotoxicity correlated with target NKG2D ligand expression (P=0.0002). Blocking the TCR or MHC class I did not affect cytotoxicity (P>0.22). CD8+ cell-mediated lysis dropped 48% when the NKG2D receptor was blocked. Day 7 CEC aggressively lysed myeloma cells in an MHC- and non-MHC-restricted fashion, through the NKG2D receptor. DISCUSSION: Because MHC expression is often down-regulated on tumor cells and the NKG2D ligands are generally specific to malignant cells, the adoptive transfer of CEC that kill through different pathways may circumvent tumor-resistant mechanisms and improve outcomes.

CD8 Antigens↗
PubMed2001

Biological purging of breast cancer cells using an attenuated replication-competent herpes simplex virus in human hematopoietic stem cell transplantation.

Autologous hematopoietic stem cell transplantation after myelosuppressive chemotherapy is used for the treatment of high-risk breast cancer and other solid tumors. However, contamination of the autologous graft with tumor cells may adversely affect outcomes. Human hematopoietic bone marrow cells are resistant to herpes simplex virus type 1 (HSV-1) replication, whereas human breast cancer cells are sensitive to HSV-1 cytotoxicity. Therefore, we examined the utility of G207, a safe replication-competent multimutated HSV-1 vector, as a biological purging agent for breast cancer in the setting of stem cell transplantation. G207 infection of human bone marrow cells had no effect on the proportion or clonogenic capacity of CD34+ cells but did enhance the proliferation of bone marrow cells in culture and the proportion of CD14+ and CD38+ cells. On the other hand, G207 at a multiplicity of infection of 0.1 was able to purge bone marrow of contaminating human breast cancer cells. Because G207 also stimulates the proliferation of human hematopoietic cells, it overcomes a limitation of other purging methods that result in delayed reconstitution of hematopoiesis. The efficient infection of human bone marrow cells in the absence of detected toxicity suggests that HSV vectors may also prove useful for gene therapy to hematopoietic progenitor cells.

Bone Marrow Cells↗
PubMed2001

Ex vivo cytokine activation of peripheral blood stem cells: a potential role for adoptive cellular immunotherapy.

Ex vivo activation of peripheral blood stem cells (PBSC) using interleukin-2 (IL-2) results in cytotoxic effector cells that may possess beneficial in vivo effects. We proposed to evaluate ex vivo stimulation of PBSC using various cytokines alone or in combination to optimize their function. Cytokine-activated PBSC were analyzed for tumor-directed cytotoxicity and their ability to remove tumor cells from long-term clonogenic assays. Mononuclear cells were obtained from the apheresis products of normal donors and cultured with IL-2 (1000 U/ml), interferon-alpha (IFN-alpha) (1000 U/ml), or IL-12 (50 U/ml) either alone or in combinations at 37 degrees C and 5% CO(2) for 24 h. Colony-forming unit-tumor (CFUT) assays were initiated using cytokine-activated PBSC with varying concentrations of MCF-7 or SKBR-3 human breast cancer cells. Standard 4-h (51)Cr-release assays were performed with cytokine-activated PBSC using MCF-7 or SKBR-3 cells as targets. Activation of PBSC with IL-2, IFN-alpha, or IL-12 resulted in enhanced cytotoxicity against the two breast cancer cell lines when compared to controls. PBSC activated with IL-2 and IFN-alpha or IL-2 and IL-12 were more cytotoxic than PBSC activated with single cytokines (p = 0.0004 for MCF-7 cells and p < 0.001 for SKBR-3 cells). Using clonogenic assays, IL-2-activated PBSC reduced the number of CFU-T to a greater extent than did IL-12 or IFN-alpha-activated PBSC (p = 0.0006). However, PBSC activated with a combination of IL-2 and IFN-alpha or IL-2 and IL-12 demonstrated 95% and 90% reductions, respectively, compared to 79% reduction using IL-2-activated PBSC (p < 0.0001). The greatest reduction in cytotoxicity occurred in the cell populations depleted of CD56(+) cells (p = 0.016) and CD8(+) CD56(+) cells (p = 0.002), suggesting that the effector cell population includes a combination of cytotoxic CD8(+) T cells and CD56(+) natural killer cells. These results demonstrate that the ex vivo activation of PBSC with cytokines, either alone or in combination, enhances cytotoxicity against, and removal of two human breast cancer cells. The combinations of IL-2 with IFN-alpha or IL-12 are most beneficial in cytotoxicity and purging assays. These results could play an important role in designing adoptive cellular immunotherapy clinical trials in the autologous hematopoietic stem cell transplant setting.

Blood Component Removal↗
PubMed2000

Platelet transfusions: utilization and associated costs in a tertiary care hospital.

We implemented a prospective study to evaluate platelet transfusion utilization, resource use, and costs in a tertiary care hospital over a 6-month period. All hospitalized patients receiving platelet transfusions between July and December 1996 were followed prospectively to determine platelet use and costs. Clinical and financial data were collected, evaluated, and compared to identify trends in resource utilization based on admitting service and platelet-refractory status. One thousand nine hundred forty-four platelet units were transfused to 245 hospitalized patients (50.6% male, mean age 49 years) during the study period. The majority of platelet units transfused were single donor (N = 1,460, 75%) and administered to bone marrow patients and patients with a hematological malignancy/disorder. Median hospitalization costs per admission were $27,750, ranging from a high of $58,729 for admission to the Bone Marrow Transplant service to $13,856 per admission to the Internal Medicine/Other service. Patients were refractory to platelet transfusions during 21.6% of hospitalizations. Hospital stays were longer (35.0 days vs. 14.4 days, P < 0.001) and inpatient hospital costs ($103,956 vs. $37,817, P < 0.001) were more than two and a half times higher for patients refractory to platelet transfusions. Platelet utilization, resource use, and costs vary by admitting service. Refractoriness to platelet transfusion was associated with significantly greater costs and lengths of stay. Monitoring platelet transfusion practices, particularly for patients refractory to platelet transfusions, may be beneficial for limiting costs and improving efficacy.

Adult↗
PubMed2000

Docetaxel-induced mobilization of hematopoietic stem cells in a murine model: kinetics, dose titration, and toxicity.

OBJECTIVE: Docetaxel (DXT) is an anticancer agent that has demonstrated therapeutic efficacy against solid tumors, particularly breast cancer. Based on the use of hematopoietic stem cell (HSC) transplantation to restore hematopoietic reconstitution after myeloablative therapy, this study was performed to determine if DXT could mobilize HSCs in vivo. MATERIALS AND METHODS: C57Bl/6 mice were injected intraperitoneally with varying doses of DXT (equivalent to human doses of 40 to 120 mg/m(2)). Spleens were harvested on days 2, 4, 6, 8, 10, and 12 after DXT administration for recovery of mononuclear cells (MNCs). The number of HSCs present within the MNCs was determined by clonogenic assay for colony-forming units in culture (CFU-C) and by FACS analysis for CD34(+) cells. Peripheral blood samples were obtained at the time of spleen harvest to determine the hematologic profile. Liver and renal function tests were performed to monitor toxicity. RESULTS: DXT mobilize d HSCs in a dose- and time-dependent manner. When measured by the CFU-C assay, maximal mobilization of HSC (>10-fold increase in control; p<0.01) was observed at a dose of 30 mg/kg (equivalent to human dose of 75 mg/m(2)) on day 7. The number of mobilized HSCs peaked on days 6 to 8 at all doses of DXT tested. There was no evidence of weight loss, liver, or renal toxicity at any of the DXT doses tested. CONCLUSION: These results indicate that DXT efficiently mobilizes HSCs in a murine model and provide the rationale for similar studies in a clinical trial.

Animals↗
PubMed2000

Outcomes of high-dose chemotherapy and autologous stem cell transplant in isolated locally recurrent breast cancer: a multicenter evaluation.

To determine the outcomes of women with isolated loco-regional recurrence (LRR) of breast cancer treated with high-dose chemotherapy (HDCT) and autologous stem cell transplantation (ASCT) following conventional therapy, we conducted a retrospective review of 58 patients from five institutions treated between 1990 and 1998. Forty-five patients (78%) had > or = 2 poor prognostic factors (PPF) (defined as disease-free interval preceding LRR < or = 2 years, hormone receptor negative/refractory disease, and incomplete resection). At median follow-up of 14.2 (0.5-72) months, 36 patients (62%) developed progressive disease. Disease progression usually occurred at local (27 patients) vs distant (nine patients) sites. Median time to disease progression following ASCT was 6.1 (1.3-31.4) months. At last follow-up, 23 patients (40%) had expired (all due to disease progression), and 13 (22%) were alive with, and 22 (38%) without progressive disease. By Kaplan-Meier analysis, the estimated median PFS and OS was 20.3 and 29.2 months, respectively. In a multivariate model, complete remission at time of HDCT and estrogen-receptor positive disease were predictive of significantly longer PFS and OS. The survival of this cohort was similar to previous reports of those treated with conventional therapy alone, and to those with distant metastases treated with HDCT. Frequent progression locally, suggests that strategies to improve local disease control are needed.

Adult↗
PubMed2000

Mobilization, collection, and processing of autologous peripheral blood stem cells: development of a clinical process with associated costs.

We surveyed five academic medical centers to develop a clinical process for patients undergoing cytokine mobilization and leukapheresis prior to autologous peripheral blood stem cell transplantation. Costs were obtained from three centers and applied to each component of the pathway. Costs were divided into three categories: (1) pre-apheresis evaluation; (2) process of apheresis; (3) post-apheresis and peripheral blood stem cells processing. All centers participated in the development of the leukapheresis pathway. Because charges vary greatly among institutions, costs were determined from three of the institutions and a mean was calculated for each of the components of the process. Pre-apheresis costs consisted of central line placement, blood work, and the price of cytokine (rhG-CSF). Costs associated with apheresis included professional fees (for physicians and nurses), leukapheresis with stem cell cryopreservation, storage, sterility testing, analysis of circulating CD34+ cell counts, and 1 day of cytokine therapy. The post-apheresis process included thawing with sterility testing along with CD34+ cell number analysis and the performance of clonogenic assays. Total costs were as follows: (1) pre-apheresis, $2711; (2) apheresis, $2990; and, (3) post-apheresis/stem cell processing, $754. This survey from five academic medical centers provides the average costs associated with three main components of the apheresis procedure. Because many patients require multiple aphereses, interventions to achieve target CD34+ cell collections in as few collections as possible would result in significant cost reduction.

Colony-Forming Units Assay↗
PubMed1999

Systemic antitumor immunity in experimental brain tumor therapy using a multimutated, replication-competent herpes simplex virus.

Replication-competent, attenuated herpes simplex virus (HSV) vectors have been developed for viral oncolytic therapy of primary and metastatic malignant brain tumors. However, the role of the host immune responses in the brain has not been elucidated. N18 neuroblastoma cells were used as a tumor model in syngeneic A/J mice to test the therapeutic efficacy of G207, a conditionally replicating HSV vector, in an immunocompetent condition. G207 inoculated intraneoplastically exhibited a prominent oncolytic antitumor effect in mice harboring N18 tumors in the brain or subcutaneously, and, in addition, elicited a systemic antitumor immune response. Subcutaneous tumor therapy with G207 caused regression of a remote, established tumor in the brain or in the periphery, which was potentially mediated by the systemic antitumor immune response, and provided persistent tumor-specific protection against N18 tumor rechallenge in the brain as well as in the periphery. Antitumor immunity was associated with an elevation of specific CTL activity against N18 tumor cells that persisted for at least 13 months. The results suggest that the oncolytic antitumor action of replication-competent HSV may be augmented by induction of specific and systemic antitumor immunity effective both in the periphery and in the brain.

Animals↗
PubMed1999

Improvement of gene transduction efficiency in T lymphocytes using retroviral vectors.

Successful gene transfer into T lymphocytes would provide a useful therapeutic modality for the treatment of various diseases and a valuable way to study T cell functions. Currently, most protocols involving gene transfer into T lymphocytes utilize amphotropic retroviral vectors. However, transduction efficiency using these vectors is relatively low because of the high proportion of resting cells, the concentration-dependent growth manner of T lymphocytes, and the low titer of retroviral vectors. In this article we define conditions that provide high levels of transduction by using IL-2 prestimulation and LipofectAMINE for both mouse and human T lymphocytes. We compared the effects of IL-2 prestimulation on transduction efficiencies at different time points and achieved maximum transfer levels at 72 hr after the incubation. By combining the best prestimulation time and cationic lipids-LipofectAMINE at a dose of 0.8 microM, the transduction efficiencies were increased to 45-75% (62.3 +/- 4.3%) in human T lymphocytes and to 21-33% (27 +/- 1.42%) in murine T lymphocytes as determine by FDG staining and X-Gal visualization, compared with 5% with conventional methods. These results indicate that transduction efficiencies in T lymphocytes can be significantly improved by a prolonged preincubation with IL-2 and by the addition of LipofectAMINE.

Animals↗
PubMed1999

Survival after autologous hematopoietic stem cell transplantation for patients with inflammatory breast carcinoma.

BACKGROUND: The authors retrospectively determined the clinical outcome of patients with inflammatory breast carcinoma (IBC) treated with high dose chemotherapy (HDC) and autologous bone marrow (ABM) or peripheral blood stem cell (PBSC) support. METHODS: Twenty-four consecutive patients with IBC received HDC, including escalating doses of carboplatin (range, 1.2-1.8 g/m2) and cyclophosphamide (range, 4.8-6.0 g/m2) over 3 days followed by ABM (n=5) or PBSC infusion (n=19). Restaging evaluation was performed 100 days after transplant, every 6 months for 2 years, and then yearly thereafter. After transplantation, fifteen patients received immunotherapy with interleukin-2 (IL-2) or IL-2 and interferon-alpha. RESULTS: The 2-year estimated disease free survival (DFS) and overall survival (OS) for these patients were 71% (90% confidence interval [CI], 55-87%) and 73% (90% CI, 53-93%), respectively. The median follow-up of surviving patients was 19 months (range, 8-68 months). Six patients developed disease recurrence at a median of 10 months (range, 4-16 months) after transplantation. Four of these 6 patients died from metastatic disease at a median of 18 months (range, 14-21 months). Using the generalized Wilcoxon test and the Cox proportional hazards regression model, patients with tumors that demonstrated estrogen receptors had an improved DFS (P=0.03). CONCLUSIONS: Combining HDC and ABM or PBSC for patients with IBC may yield an improved OS and DFS.

Adenocarcinoma↗
PubMed1999

Paclitaxel vs cyclophosphamide in peripheral blood stem cell mobilization: comparative studies in a murine model.

Paclitaxel is a promising drug for the treatment of breast and ovarian cancer. It also may play a role in mobilization of peripheral blood stem cells (PBSC), as an alternative to cyclophosphamide (Cy). We investigated the PBSC-mobilizing potential of paclitaxel compared to Cy in a murine model. C57B1/6 mice were primed with intraperitoneal injections of Cy (200 mg/kg) or paclitaxel (60 mg/kg) and were sacrificed 4, 6, 8, or 10 days later. Spleens were harvested and processed to obtain low-density mononuclear cells that were used as PBSC. The number of hematopoietic progenitors (CFU-C) on day 4 was significantly higher in the paclitaxel group when compared to mice receiving Cy (72.0 +/- 1.8 vs 9.8 +/- 2.8, p < 0.001). By day 6, CFU-C became significantly higher in the Cy-treated group compared to the paclitaxel-treated group (195.6 +/- 31.9 vs 95.8 +/- 20.7, p < 0.05) and this trend was maintained. However, the total number of CFU-C recovered per spleen was greater in the paclitaxel-treated group (1.27 x 10(5) +/- 0.53 x 10(5) vs 1.06 x 10(5) +/- 0.36 x 10(5), NS). In contrast to paclitaxel, mobilization with Cy was associated with marked perturbation in the proportion of lymphoid cell subsets in the PBSC population along with functional impairment of lymphocytes. After 24 hours of in vitro IL-2 activation, the cytotoxic effector cell function of the Cy-mobilized PBSC population was lower than that of paclitaxel-mobilized cells when tested against three tumor cell lines (B16, melanoma; C1498, AML; and Yak-1, lymphoma). These results indicate that paclitaxel is an efficient mobilizer of PBSC, leading to early (day 4 to 6) mobilization of PBSC when compared to Cy (day 6 to 8). In addition, paclitaxel was associated with less perturbation of phenotypic and functional characteristics of cells contained within the mobilized PBSC population.

Animals↗
PubMed1999

Immunotherapy with interleukin-2 and alpha-interferon after IL-2-activated hematopoietic stem cell transplantation for breast cancer.

We previously demonstrated findings suggestive of autologous GVHD in patients receiving IL-2-activated peripheral blood stem cells (PBSC) with IL-2 after transplantation. A pilot study was designed to test tolerability, feasibility and frequency of autologous GVHD and engraftment using IL-2 and alpha-IFN post-transplantation. After cyclophosphamide (6 g/m2) and carboplatin (1800 mg/m2), patients with high-risk stage II or III breast cancer received chemotherapy and rhG-CSF mobilized autologous PBSC that had been cultured in IL-2 for 24 h. Subcutaneous administration of IL-2 began on day 0 at 6 x 10(5) IU/m2/day for 5 of 7 days each week and continued for 4 weeks. Once engraftment occurred, alpha-IFN was initiated at a dose of 1 x 10(6)/m2/day subcutaneously for 30 days. Thirty-four consecutive patients with stage II (n=20), IIIA (n=6) and IIIB (n=8) disease were treated. All patients were without evidence of disease at the time of transplantation. The average time required for the ANC to reach 500/mm3 was 10 days (range: 8-11 days) and for platelets to reach 20000/mm3 was 10.7 days (range: 6-21 days). Forty-seven percent of patients (n=16) completed the full course of immunotherapy; the remaining patients received attenuated doses due to patient's request (n=6), development of temperature >38 degrees C (n=3), development of neutropenia (n=3), serious infection (n=1) and miscellaneous reasons (n=5). Four patients experienced transient moderate toxicities (level 3) including elevated liver function tests, nausea, rash and capillary leak syndrome. Pathological findings suggestive of skin GVHD developed in 43% of patients (12/28 patients) when skin biopsies were evaluated in a blinded fashion. At 13 months post-transplant (median; range: 5-24 months), 28 patients (82%) remain disease-free. These results demonstrate the feasibility and toxicity of this regimen along with pathological findings compatible with autologous GVHD of the skin.

Adult↗
PubMed1999

Differential effects of IL-2 incubation on hematopoietic potential of autologous bone marrow and mobilized PBSC from patients with hematologic malignancies.

Culturing of hematopoietic progenitor cells for 24 h with IL-2 generates cytotoxic effector cells that mediate in vitro and possibly in vivo antitumor activity. We examined the effect of IL-2 incubation on progenitor cells from 24 patients with hematologic malignancies using paired autologous bone marrow (ABM) and PBSC to determine differences in hematopoietic potential. Cells were cryopreserved and stored in liquid nitrogen until conditioning therapy was completed. After thawing, cells were incubated with IL-2 for 24 h at 37 degrees C. Paired samples of ABM and PBSC from the same patient were analyzed for nucleated and mononuclear cell number, CD34 antigen expression, and colony-forming unit (CFU) activity before and after IL-2 incubation. There was a significant decrease in the average number of mononuclear cells (MNC) (x10(8)/kg) (<0.001) and CD34+ cells (x10(6)/kg) (0.006) from both ABM and PBSC after 24 h IL-2 culture (ABM MNC: 0.6+/-0.1 vs. 0.4+/-0.0, p = <0.001; PBSC MNC: 4.4+/-0.5 vs. 3.7+/-0.4, p = 0.03; ABM CD34+: 2.4+/-0.5 vs. 1.3+/-0.3, p = <0.001; PBSC CD34+: 6.6+/-1.8 vs. 5.0+/-1.2, p = 0.05). However, whereas ABM CFU/10(5) MNC plated (269.3+/-47.2 vs. 385.6+/-70.6) were significantly increased (p = 0.005), there was no change in PBSC CFU (271.0+/-47.2 vs. 257.3+/-48.5). The mean plating efficiency (%) of ABM CD34+ cells was markedly increased after IL-2 incubation (10.1+/-3.3 vs. 19.0+/-7.2, p = 0.04), although it was lower than that of PBSC CD34+ cells, which did not change significantly in culture (29.4+/-5.5 vs. 36.0+/-6.5). Additional work is in progress to determine the cause and significance of the enhanced plating efficiency of the ABM progenitor cells.

Adult↗
PubMed1999

Analysis and characterization of hematopoietic progenitor cells from fetal bone marrow, adult bone marrow, peripheral blood, and cord blood.

Hematopoietic stem cell transplantation has been increasingly used to replace a defective hematopoietic system and to treat various genetic defects as well as malignant diseases. However, the limitations of conventional bone marrow transplantation have stimulated an intense interest in exploring the use of alternative sources of hematopoietic stem cells, including peripheral blood mononuclear cells (PBMC) and cord blood (CB). A major investigative effort of our laboratory has been focused on evaluating fetal bone marrow (FBM) for transplantation. The current study compares and characterizes the functional and phenotypic characteristics of FBM, CB, adult bone marrow (ABM), and PBMC by clonogenicity assays, immunogenicity, and the quantification of progenitor cells. There was a striking difference in the proportion of CD34+ cells in FBM, ABM, PBMC, and CB (24.6%, 2.1%, 0.5%, and 2.0%, respectively). The clonogenic potential, as measured by colony forming unit in culture (CFU-C) assay, was significantly higher in FBM when compared with ABM, PBMC, and CB (202.5, 73.5, 40.8, and 65.5 colonies/10(5) cells, respectively). There was a significant decrease in proliferative responsiveness in mixed lymphocyte reaction (MLR) assay of FBM and CB compared with ABM and PBMC. These observations indicate that each source of hematopoietic stem cells has different intrinsic properties closely correlated with ontogenetic age that is a vital determinant for phenotypic characteristics, lineage commitments, immunogenicity, and proliferative potentials.

Adult↗
PubMed1999

Chronic myelogenous leukemia. Curable with early diagnosis and treatment.

CML is diagnosed most commonly in middle-aged patients following referral from primary care physicians. The majority of patients live at least 5 years when the disease is diagnosed and treated in the chronic phase. Survival is clearly prolonged by therapy, including interferon alfa-2b (used alone or in combination with other agents) and allogeneic bone marrow transplantation. With ongoing advances in allogeneic transplantation allowing matched related and unrelated donor transplants in older individuals with manageable complications, the need for timely identification of CML patients who are suitable candidates for this potentially curative intervention is critical.

Antineoplastic Agents↗
PubMed1998

Idiopathic giant cell myocarditis after autologous hematopoietic stem cell transplantation and interleukin-2 immunotherapy: a case report.

BACKGROUND: Interleukin-2 (IL-2) is used in the treatment of solid tumors and hematologic malignancies. Sudden death is a rare complication of IL-2 treatment. METHODS: A patient with lymphoma underwent chemoradiotherapy myeloablation and autologous stem cell transplantation. The stem cells were cultured in IL-2 (6000 IU/mL) for 24 hours prior to infusion. After engraftment, treatment with IL-2 (1.8 x 10(6) IU/m2/day administered subcutaneously) was begun. After 4 days of treatment, the patient suddenly died. An autopsy was performed. RESULTS: Histologic examination of the myocardium revealed a diffuse, lymphocytic infiltrate with scattered, multinucleated giant cells and foci of myocardial degeneration consistent with giant cell myocarditis. The lymphocytes were predominantly CD4 positive T cells, and the majority of these cells stained with antibodies for perforin, suggesting an unusual cytolytic role for these lymphocytes. DNA end-labeling of myocardial tissue sections revealed numerous apoptotic myocytes within the lymphocytic infiltrate. CONCLUSIONS: To the authors' knowledge, this is the first report of giant cell myocarditis in association with high dose chemotherapy, transplantation, and IL-2 immunomodulation. The authors suggest that the cytokine imbalance produced by IL-2 may have initiated a preferential activation of T helper cells and an autoimmune phenomenon manifesting as giant cell myocarditis.

Antineoplastic Agents↗
PubMed1997

Suppression of progenitor cell growth by vancomycin following autologous stem cell transplantation.

The occurrence of hematologic side-effects resulting from the use of vancomycin is rare. Prior to this report, vancomycin-induced neutropenia was believed to be due to a hypersensitivity reaction since antibodies directed against circulating neutrophils have been discovered in the serum of some patients. We demonstrate suppression of hematopoietic bone marrow progenitor cells in a patient experiencing vancomycin-induced neutropenia after an autologous hematopoietic stem cell transplantation for multiple myeloma. A bone marrow (BM) specimen obtained at the time of neutropenia demonstrated direct suppression of progenitor cell growth in vitro when vancomycin was added at increasing concentrations (1, 10 and 50 microg/ml). No such trend was noted in a BM sample from the same patient obtained 11 months prior to transplantation and a normal control BM. The decrease in the total number of colony-forming units (CFU) was statistically significant at all the dose levels of vancomycin when compared to the number of CFU in the baseline BM sample (P < 0.05). The myeloid maturation arrest observed in the bone marrow sample obtained during the period of neutropenia and the dose dependent growth inhibition by vancomycin observed in vitro suggest a novel nonimmune mechanism of hematologic effects due to suppression of bone marrow progenitor cell growth.

Anti-Bacterial Agents↗