Current practices in the oral management of the patient undergoing chemotherapy or bone marrow transplantation

Abstract The oral complications associated with cancer chemotherapy and bone marrow transplantation may be prevented or ameliorated by aggressive dental and oral hygiene interventions. Pretherapy dental evaluation and medically necessary oral care can eliminate potential sites of infection and trauma. A multidisciplinary approach, systematic oral assessment and consistent oral hygiene measures are critical and may be the most important factors in the prevention of significant complications.

Endothelial selectins and vascular cell adhesion molecule-1 promote hematopoietic progenitor homing to bone marrow

The adhesive mechanisms allowing hematopoietic progenitor cells (HPC) homing to the bone marrow (BM) after BM transplantation are poorly understood. We investigated the role of endothelial selectins and vascular cell adhesion molecule-1 (VCAM-1) in this process. Lethally irradiated recipient mice deficient in both P-and E-selectins (P/E-/-), reconstituted with minimal numbers (</=5 x 10(4)) of wild-type BM cells, poorly survived the procedure compared with wild-type recipients. Excess mortality in P/E-/- mice, after a lethal dose of irradiation, was likely caused by a defect of HPC homing. Indeed, we observed that the recruitment of HPC to the BM was reduced in P/E-/- animals, either splenectomized or spleen-intact. Homing into the BM of P/E-/- recipient mice was further compromised when a function-blocking VCAM-1 antibody was administered. Circulating HPC, 14 hr after transplantation, were greatly increased in P/E-/- mice treated with anti-VCAM-1 compared with P/E-/- mice treated with just IgG or wild-type mice treated with either anti-VCAM-1 or IgG. Our results indicate that endothelial selectins play an important role in HPC homing to the BM. Optimal recruitment of HPC after lethal doses of irradiation requires the combined action of both selectins and VCAM-1 expressed on endothelium of the BM.

[Neutropenia]

The authors reviewed the subject of neutropenia in what concern its definition, pathophysiology, clinical features, diagnosis and principles of treatment. A new pathophysiological classification of neutropenia and an evaluation of neutropenic patients are proposed. The extent of laboratory evaluation depends greatly on the duration and severity of the neutropenia. The hematopoietic growth factors controlling the growth, development, differentiation and activation of the hematopoietic progenitor cells have revolutionized the treatment of neutropenia.

Cyclical neutropenia and other periodic hematological disorders: a review of mechanisms and mathematical models

Although all blood cells are derived from hematopoietic stem cells, the regulation of this production system is only partially understood. Negative feedback control mediated by erythropoietin and thrombopoietin regulates erythrocyte and platelet production, respectively, but the regulation of leukocyte levels is less well understood. The local regulatory mechanisms within the hematopoietic stem cells are also not well characterized at this point. Because of their dynamic character, cyclical neutropenia and other periodic hematological disorders offer a rare opportunity to more fully understand the nature of these regulatory processes. We review the salient clinical and laboratory features of cyclical neutropenia (and the less common disorders periodic chronic myelogenous leukemia, periodic auto-immune hemolytic anemia, polycythemia vera, aplastic anemia, and cyclical thrombocytopenia) and the insight into these diseases afforded by mathematical modeling. We argue that the available evidence indicates that the locus of the defect in most of these dynamic diseases is at the stem cell level (auto-immune hemolytic anemia and cyclical thrombocytopenia seem to be the exceptions). Abnormal responses to growth factors or accelerated cell loss through apoptosis may play an important role in the genesis of these disorders.

Cyclical neutropenia and the peripheral control of white blood cell production

Cyclical neutropenia (CN) is an interesting dynamic hematological disease in which the neutrophils spontaneously oscillate from approximately normal levels to near zero with a period between 19 and 21 days. In the only known animal model for this disorder, the grey collie, the disease's single apparent difference from human CN is the smaller period of 11-15 days. CN can be treated using the cytokine G-CSF which decreases the period (to about 14 days in humans), increases the mean value, and elevates the amplitude of the oscillations. After reviewing the clinical and laboratory data on this disease, we examine the proposition that CN is due to a loss of stability in the peripheral negative feedback control of neutrophil production. This is accomplished by the development of a physiologically realist mathematical model for the system. We conclude that there is no consistent way in which such a destabilization can give rise to either the clinical or laboratory characteristics of CN. Rather it seems more likely that the oscillations of CN are generated within the pluripotential stem cell population.

Correlation of in vitro fluconazole susceptibility with clinical outcome for severely ill patients with oropharyngeal candidiasis

We investigated the correlation between in vitro susceptibility to fluconazole and clinical response in severely ill patients with oropharyngeal candidiasis treated with fluconazole. The study included 48 adult patients, of whom 23 were neutropenic (absolute neutrophil count, < 500/mm3). Forty-eight isolates (20 Candida albicans, 12 Candida krusei, 10 Candida kefyr, 3 Torulopsis glabrata, and 3 Candida tropicalis) were tested for susceptibility to fluconazole with use of the macrodilution method of the National Committee for Clinical Laboratory Standards. A strain was considered to be susceptible to fluconazole if the MIC was < or = 8 micrograms/mL and resistant if the value was > or = 64 micrograms/mL. All but one of the resistant strains were C. krusei isolates. Species of causative Candida, persistent neutropenia, and susceptibility to fluconazole were significant predictors of clinical response by univariate analysis. Logistic regression analysis indicated that the only significant factor was the species of Candida isolates, validating the recently recommended MIC breakpoint and the correlation between clinical outcome and in vitro antifungal susceptibility.

Defective natural killer cell activity of peripheral blood lymphocytes correlates with the degree of neutropenia in patients with chronic idiopathic neutropenia of adults

Natural killer cell activity (Nka) of peripheral blood mononuclear cells (PBMCs) against K562 cell targets was assessed in 66 patients with chronic idiopathic neutropenia of adults (CINA) using the 16-h 51Cr-release assay. It was found that CINA patients exhibited significantly lower Nkr than normal subjects, which strongly correlated with the degree of neutropenia and the numbers of circulating neutrophils. Patients' NKa was increased by recombinant human interleukin-2 (rhIL-2) or recombinant human interferon-alpha (rhIFN-alpha), but the values obtained did not reach the respective NKa values found in normals. However, percentages of cytokine-induced rises of NKa did not differ statistically between patients and normal subjects. No serum inhibitors of NKa were demonstrated in our patients. CINA patients had low numbers of circulating NK cells as defined by the expression of NK-cell-related surface markers CD16, CD56, and CD57. CD16+ and CD56+, but not CD57+, cells correlated with the values of baseline NKa. The numbers of all these cell subsets correlated with the degree of neutropenia and the numbers of circulating neutrophils. Using CD56+-enriched PBL suspensions, it was shown that patients' NK cells displayed normal tumor cell binding capacity and produced in vitro normal amounts of natural killer cytotoxic factor(s) against K562 cell targets upon activation with rhIFN-alpha. Finally, percentages of perforin-expressing and granzyme B-expressing CD16+ cells did not differ statistically between patients and normal controls. Based on all these observations, we concluded that CINA patients display low NKa probably because they have low numbers of circulating NK cells. No functional abnormalities of NK cells were demonstrated. The cause and the underlying mechanisms leading to NK-cell depletion in these patients remain to be clarified.

Effect of cigarette smoke on ethanol-induced gastric mucosal lesions: the role of nitric oxide and neutrophils

The roles of neutrophil aggregation, inducible nitric oxide synthase activation and chemoattractant, leukotriene B4, in potentiation of the cigarette smoke effect on ethanol-induced gastric mucosal damage were studied. Smoke exposure markedly increased gastric lesion formation following ethanol administration and this was accompanied by substantial increase in gastric mucosal leukotriene B4 concentration, myeloperoxidase and inducible nitric oxide synthase activities. Antineutrophil serum or aminoguanidine pretreatment significantly attenuated both gastric mucosal lesion formation and inducible nitric oxide synthase activity. The increased myeloperoxidase activity was abolished by antineutrophil serum but not by aminoguanidine. These data indicated that both neutrophil mobilization and inducible nitric oxide synthase activation in the gastric mucosa play an important role in the potentiating action of cigarette smoke on ethanol-induced gastric mucosal lesion formation. Increased synthesis of nitric oxide from inducible nitric oxide synthase during gastric damage may be secondary to neutrophil infiltration in the gastric mucosa. Chemoattractant leukotriene B4 could also contribute to neutrophil recruitment in the tissue.

Phagocytes and acute lung injury: dual roles for interleukin-1

Interleukin-1 (IL-1) and neutrophils are increased in lungs of patients with the acute respiratory distress syndrome (ARDS). We found that rats given IL-1 intratracheally rapidly developed lung neutrophil accumulation and a neutrophil-dependent acute edematous lung leak. Lung leak was associated with increased lung lavage cytokine-induced chemoattractant (CINC) levels and increased oxidative stress that was manifested by increased exhaled H2O2 levels and increased lung oxidized glutathione levels. IL-1-induced lung leak was decreased by treatment with superoxide dismutase (SOD), dimethylsulfoxide (DMSO), supercritical fluid-aerosolized vitamin E, interleukin-1-receptor antagonist (IL-1ra), or liposome-associated PGE1 (Lip-PGE1). Importantly, Lip-PGE1 treatment also reduced ventilator dependence in a small clinical study of ARDS patients. Another series of investigations revealed that IL-1 pretreatment could prevent lung leak in rats given IL-1 intratracheally. These findings point to the possible dual effects of IL-1 with respect to the development of acute lung injury.

Predictive value of several signs of infection as surrogate markers for mortality in a neutropenic guinea pig model of Pseudomonas aeruginosa sepsis

Infected, neutropenic animals are used as experimental models to evaluate the relative efficacies of antimicrobial agents and host-pathogen-antibiotic interactions. In the past, these models used death as the study end point. Because of the concern about use of death as an end point, we evaluated the accuracy with which various signs of infection predicted mortality in a neutropenic guinea pig model of treated and untreated Pseudomonas aeruginosa sepsis. The potential surrogate markers studied included ruffled fur, respiratory distress, diarrhea, hunched posture, lethargy, abnormal neurologic movements (twitching, paralysis of a limb), inappetence for > 48 h, the inability to ambulate, and the inability of a supine animal to stand. In addition, we evaluated whether percentage of weight loss or change in daily food and water consumption were predictive of mortality. Animals were inspected for these signs at least every 4 h during the day and every 8 h in the evening. In treated and untreated animals, 100% of subjects that were unable to ambulate or to rise from the supine position died (positive predictive value for death was 100% for either sign). Guinea pigs that could not rise from a supine position expired between 1 and 8 h after this sign was observed. Those that could not ambulate died between 4 and 40 h after that sign was observed. In treated and untreated animals, none of the survivors manifested either sign of disease (100% specificity for each sign). However, 59% of untreated and 69% of treated animals that were ambulatory were found dead at the next observation period, underscoring the rapidity with which this infection progresses to death when it enters its final stage. No other signs of infection distinguished animals that survived or died. Thus, the inability of neutropenic, infected guinea pigs to rise from a supine position and the inability to ambulate were the only signs that accurately predicted death and, therefore, are the only signs that can be used as surrogates for death in this experimental model of P. aeruginosa sepsis.

The role of neutrophils in producing hepatocellular dysfunction during the hyperdynamic stage of sepsis in rats

Although studies have shown that hepatocellular function is depressed during the early, hyperdynamic stage of sepsis, the mechanism responsible for this remains unknown. To determine whether neutrophils play any role in producing this depression, hepatocellular function was measured in neutrophil-competent and neutropenic animals subjected to sepsis. Neutropenia was induced by tail vein injection of an immunoglobulin directly against rat neutrophils (anti-neutrophil Ig) at 16 and 2 h prior to the initiation of cecal ligation and puncture (CLP, i.e., a model of polymicrobial sepsis). Neutropenia was confirmed by peripheral blood smears. Neutrophil-competent controls were given nonimmunized Ig before the onset of sepsis. Sham-operated animals received anti-neutrophil Ig or control Ig. Hepatocellular function [i.e., the maximal velocity of indocyanine green clearance (Vmax) and efficiency of the clearance (Km)] was determined by a fiber-optic catheter and in vivo hemoreflectometer at 5 h after CLP (i.e., early, hyperdynamic sepsis) or sham operation. Serum alanine aminotransferase (ALT) levels were also determined. The results indicate that although circulating levels of ALT were not elevated, hepatocellular function was significantly depressed during early sepsis. The depression in Vmax and Km was, however, prevented by neutrophil depletion, suggesting an integral role of the neutrophils in depressing hepatocellular function under such conditions. The results suggest that the prudent modulation of neutrophil function during the early stage of polymicrobial sepsis may be beneficial for preventing or delaying the occurrence of hepatocellular dysfunction.

Severe chronic neutropenia: pathophysiology and therapy

The development of recombinant-met human granulocyte-colony stimulating factor (r-metHuG-CSF) for clinical use has had a major influence on the treatment of many diseases. This impact has perhaps been greatest for treatment of severe chronic neutropenia (SCN) conditions for which there were no predictably effective treatment before the availability of these growth factors, particularly r-metHuG-CSF (Filgrastim, Amgen Inc, Thousand Oaks, CA; or Lenograstim, Rhone-Poulenc Rorer, Milan, Italy). Based on careful studies in many countries it is now known that more than 95% of these patients will respond promptly to r-metHuG-CSF treatment with normalization of the blood neutrophil levels and reduction in the occurrence of both major and minor consequences of their severe neutropenia. The availability of this treatment will undoubtedly lead to much additional research on the mechanisms governing neutrophil production and the basic mechanisms that can cause neutropenia among patients who have SCN. Among patients who have SCN those who are diagnosed to have severe congenital neutropenia (Kostmann's syndrome) or Shwachman-Diamond syndrome are at risk of developing myelodysplasia and/or acute myelogenous leukemia. The role of r-metHuG-CSF in facilitating the risk remains to be determined. Thus, it is important that long-term evaluation of the safety and efficacy of treatment of SCN and cooperation in research on these rare conditions proceed under the auspices of an international registry monitoring the clinical outcome of patients with severe congenital neutropenia.

Interleukin-6 and the granulocyte colony-stimulating factor receptor are major independent regulators of granulopoiesis in vivo but are not required for lineage commitment or terminal differentiation

Multiple hematopoietic cytokines can stimulate granulopoiesis; however, their relative importance in vivo and mechanisms of action remain unclear. We recently reported that granulocyte colony-stimulating factor receptor (G-CSFR)-deficient mice have a severe quantitative defect in granulopoiesis despite which phenotypically normal neutrophils were still detected. These results confirmed a role for the G-CSFR as a major regulator of granulopoiesis in vivo, but also indicated that G-CSFR independent mechanisms of granulopoiesis must exist. To explore the role of interleukin-6 (IL-6) in granulopoiesis, we generated IL-6 x G-CSFR doubly deficient mice. The additional loss of IL-6 significantly worsened the neutropenia present in young adult G-CSFR-deficient mice; moreover, exogenous IL-6 stimulated granulopoiesis in vivo in the absence of G-CSFR signals. Near normal numbers of myeloid progenitors were detected in the bone marrow of IL-6 x G-CSFR-deficient mice and their ability to terminally differentiate into mature neutrophils was observed. These results indicate that IL-6 is an independent regulator of granulopoiesis in vivo and show that neither G-CSFR or IL-6 signals are required for the commitment of multipotential progenitors to the myeloid lineage or for their terminal differentiation.

Controversies in new antibiotic therapy for ambulatory patients

The care of the febrile neutropenic patient has undergone a shift in the last 10 years with the realization that neutropenic patients presenting with fever do not constitute a homogeneous group. Strategies of risk assessment have allowed the testing of novel therapies including outpatient treatment with oral and intravenous antibiotics, either in combination regimens or as monotherapy; the addition of growth factors to hasten the return of the absolute neutrophil count; and the possibility of self-initiation of antibiotics by cancer patients when they develop fever. The clinical trials data regarding these new approaches will be reviewed, and areas requiring further research will be discussed.

Correlation between in-vitro susceptibility testing to itraconazole and in-vivo outcome of Aspergillus fumigatus infection

Given the increased choice of therapeutic agents and the rising incidence of serious invasive disease, it is important that reliable in-vitro methods for detecting antifungal drug resistance in Aspergillus spp. are developed. Six clinical isolates of Aspergillus fumigatus, obtained from patients in whom the clinical outcome was known, were selected for study. Each was used to examine a range of parameters affecting agar dilution and broth microdilution susceptibility test results. The in-vitro results were compared with outcome in a neutropenic mouse model of invasive aspergillosis. Groups of animals were treated with itraconazole at 25 mg/kg and 75 mg/kg and survival rates and organ burdens were determined. Itraconazole was efficacious against four isolates (susceptible) but failed for two (resistant) in the animal model of infection. Both the resistant isolates had been obtained from patients receiving itraconazole treatment with good serum concentrations of the drug. Conditions for the agar dilution test which produced results that correlated best with our in-vivo observations included the use of RPMI agar with L-glutamine buffered to pH 7 with MOPS, inoculated with 10(6)-10(7) conidia/mL and incubated for 48-72 h at 28 or 35 degrees C with a no-growth endpoint. Optimal conditions for the broth microdilution method included the use of RPMI medium with L-glutamine and 2% glucose buffered to pH 7 with MOPS, an inoculum of 2 x 10(5) conidia in 200 microL incubated for 48 h at 35 degrees C with a growth (or trace) endpoint. The MICs for the susceptible isolates were 0.12-1.0 mg/L and > or = 16 mg/L for the resistant isolates. With careful selection and standardization of test conditions it is possible to generate reproducible in-vitro susceptibility data for Aspergillus spp. that will predict clinical outcome.

Early discharge of low-risk febrile neutropenic children and adolescents with cancer

During the past decade, a relatively lower-risk patient population of febrile neutropenic children with cancer (over one-half of all these patients) has been identified. These patients can be safely discharged from the hospital before their absolute neutrophil count (ANC) exceeds 500/mm3. To evaluate the practice of early discharge of these patients, 580 consecutive episodes of chemotherapy-induced febrile neutropenia in 253 children and adolescents with cancer between June 1992 and May 1995 were reviewed. Three hundred thirty episodes ended in discharge before the patient's ANC was > 500/mm3. Patients were characterized as being at relatively lower risk if they had sterile blood cultures, were afebrile for > 24 hours, appeared well, and were thought to have evidence of marrow recovery. Of the 330 episodes, only 21 (6%) were associated with admission for recurrent fever during the subsequent 7 days. In retrospect, in only six of these 21 cases of readmission (or 2% of 330 episodes) was there evidence of bone marrow recovery, and none of the blood cultures were positive during the subsequent hospitalization. All patients who met low-risk criteria fared well during their second hospitalization. This early discharge strategy was safe and resulted in substantial cost savings.

Clinical spectrum of X-linked hyper-IgM syndrome

We report the clinical and immunologic features and outcome in 56 patients with X-linked hyper-IgM syndrome, a disorder caused by mutations in the CD40 ligand gene. Upper and lower respiratory tract infections (the latter frequently caused by Pneumocystis carinii), chronic diarrhea, and liver involvement (both often associated with Cryptosporidium infection) were common. Many patients had chronic neutropenia associated with oral and rectal ulcers. The marked prevalence of infections caused by intracellular pathogens suggests some degree of impairment of cell-mediated immunity. Although lymphocyte counts and in vitro proliferation to mitogens were normal, a defective in vitro proliferative response to antigens was observed in some patients, and additional defects of cell-mediated immunity may be presumed on the basis of current knowledge of CD40-ligand function. All patients received regular infusions of immunoglobulins. Four patients underwent liver transplantation because of sclerosing cholangitis, which relapsed in there. Three patients underwent bone marrow transplantation. Thirteen patients (23%) died of infection and/or liver disease. X-linked hyper-IgM syndrome, once considered a clinical variant of hypogammaglobulinemia, is a severe immunodeficiency with significant cellular involvement and a high mortality rate.

Bone mineralization and turnover in children with congenital neutropenia, and its relationship to treatment with recombinant human granulocyte-colony stimulating factor

Bone mineral content (BMC) of the radius was measured using single photon absorptiometry (SPA) in nine children with congenital neutropenia. Five had normal values. Two children with severe congenital neutropenia (SCN) had low BMC, and two boys with Schwachman syndrome had biochemistry suggestive of rickets.