Both CD34+38+ and CD34+38- cells home specifically to the bone marrow of NOD/LtSZ scid/scid mice but show different kinetics in expansion

Human hemopoietic stem cells (HSC) have been shown to engraft, differentiate, and proliferate in the hemopoietic tissues of sublethally irradiated NOD/LtSZ scid/scid (NOD/SCID) mice. We used this model to study homing, survival, and expansion of human HSC populations from different sources or phenotype. We observed that CD34+ cells homed specifically to bone marrow (BM) and spleen, but by 3 days after injection, survived only in the BM. These BM-homed CD34+ cells proliferated intensively and gave rise to a 12-fold, 5.5-fold, and 4-fold expansion in 3 days for umbilical cord blood, adult mobilized peripheral blood, and adult BM-derived cells, respectively. By injection of purified subpopulations, it was demonstrated that both CD34+38+ and CD34+38- umbilical cord blood HSC homed to the BM and expanded. Importantly, kinetics of expansion were different: CD34+38+ cells started to increase in cell number from day 3 onwards, and by 4 wk after injection, virtually all CD34+ cells had disappeared. In contrast, CD34+38- cells remained quiescent during the first week and started to expand intensively from the third week on. In this paper, we have shown that homing, survival, and expansion of stem cells are three independent phenomena important in the early phase of BM engraftment and that kinetics of engraftment differ between CD34+38+ and CD34+38- cells.

Congenital sodium diarrhea is an autosomal recessive disorder of sodium/proton exchange but unrelated to known candidate genes

BACKGROUND & AIMS

Congenital sodium diarrhea (CSD) is caused by defective sodium/proton exchange with only 6 sporadic cases reported. The genetics of the disease have not been established. We studied 5 infants with secretory diarrhea, identified in a circumscribed rural area in Austria, to define the mode of transmission and the involvement of candidate genes known to encode for sodium/proton exchangers (NHEs).

METHODS

We collected clinical and laboratory data from 5 affected patients, analyzed the pedigrees of their families, and performed homozygosity mapping and multipoint linkage analysis studies in 4 candidate regions known to contain NHE genes.

RESULTS

The diagnosis of CSD in 4 of 5 patients was based on daily fecal sodium excretion between 98 and 190 mmol/L, hyponatremia, metabolic acidosis, and low-to-normal urinary sodium concentrations. Pedigree analysis of the affected 2 CSD families revealed parental consanguinity and a common single ancestor 5 generations ago. Homozygosity mapping and/or multipoint linkage analysis excluded the NHE1 locus on chromosome 1, NHE2 locus on chromosome 2, NHE3 locus on chromosome 5, and NHE5 locus on chromosome 16 as potential candidate genes for CSD in this pedigree. Results on NHE4 were inconclusive because the precise chromosomal location of this NHE gene in humans is currently unknown.

CONCLUSIONS

Our data indicate that CSD is an autosomal recessive disorder but is not related to mutations in the NHE1, NHE2, NHE3, and NHE5 genes encoding for currently known sodium/proton exchangers.

Successful stem cell transplantation following orthotopic liver transplantation from the same haploidentical family donor in a girl with hemophagocytic lymphohistiocytosis

The case of a 4-month-old girl with familial hemophagocytic lymphohistiocytosis is described. The patient underwent stem cell transplantation from her haploidentical mother 2 months after receiving a living-related liver transplant from the same donor for acute hepatic failure. Conditioning regimen consisted of 16 mg/kg busulfan, 200 mg/kg cyclophosphamide, 10 mg/kg thiothepa, and antithymocyte globulin. Myeloid engraftment occurred on day +10, but CD3(+) cells of recipient origin remained. To convert the T-cell chimerism, the patient received donor lymphocyte infusion on day +43, and subsequently the allelic pattern changed to complete donor genotype on day +57. Four months after stem cell transplantation the patient is disease free, with complete donor chimerism in bone marrow and stable hepatic graft function without any immunosuppressive therapy. (Blood. 2000;96:3997-3999)

The Vienna classification of gastrointestinal epithelial neoplasia

BACKGROUND

Use of the conventional Western and Japanese classification systems of gastrointestinal epithelial neoplasia results in large differences among pathologists in the diagnosis of oesophageal, gastric, and colorectal neoplastic lesions.

AIM

To develop common worldwide terminology for gastrointestinal epithelial neoplasia.

METHODS

Thirty one pathologists from 12 countries reviewed 35 gastric, 20 colorectal, and 21 oesophageal biopsy and resection specimens. The extent of diagnostic agreement between those with Western and Japanese viewpoints was assessed by kappa statistics. The pathologists met in Vienna to discuss the results and to develop a new consensus terminology.

RESULTS

The large differences between the conventional Western and Japanese diagnoses were confirmed (percentage of specimens for which there was agreement and kappa values: 37% and 0.16 for gastric; 45% and 0.27 for colorectal; and 14% and 0.01 for oesophageal lesions). There was much better agreement among pathologists (71% and 0.55 for gastric; 65% and 0.47 for colorectal; and 62% and 0.31 for oesophageal lesions) when the original assessments of the specimens were regrouped into the categories of the proposed Vienna classification of gastrointestinal epithelial neoplasia: (1) negative for neoplasia/dysplasia, (2) indefinite for neoplasia/dysplasia, (3) non-invasive low grade neoplasia (low grade adenoma/dysplasia), (4) non-invasive high grade neoplasia (high grade adenoma/dysplasia, non-invasive carcinoma and suspicion of invasive carcinoma), and (5) invasive neoplasia (intramucosal carcinoma, submucosal carcinoma or beyond).

CONCLUSION

The differences between Western and Japanese pathologists in the diagnostic classification of gastrointestinal epithelial neoplastic lesions can be resolved largely by adopting the proposed terminology, which is based on cytological and architectural severity and invasion status.

The Vienna classification of gastrointestinal epithelial neoplasia

BACKGROUND

Use of the conventional Western and Japanese classification systems of gastrointestinal epithelial neoplasia results in large differences among pathologists in the diagnosis of oesophageal, gastric, and colorectal neoplastic lesions.

AIM

To develop common worldwide terminology for gastrointestinal epithelial neoplasia.

METHODS

Thirty one pathologists from 12 countries reviewed 35 gastric, 20 colorectal, and 21 oesophageal biopsy and resection specimens. The extent of diagnostic agreement between those with Western and Japanese viewpoints was assessed by kappa statistics. The pathologists met in Vienna to discuss the results and to develop a new consensus terminology.

RESULTS

The large differences between the conventional Western and Japanese diagnoses were confirmed (percentage of specimens for which there was agreement and kappa values: 37% and 0.16 for gastric; 45% and 0.27 for colorectal; and 14% and 0.01 for oesophageal lesions). There was much better agreement among pathologists (71% and 0.55 for gastric; 65% and 0.47 for colorectal; and 62% and 0.31 for oesophageal lesions) when the original assessments of the specimens were regrouped into the categories of the proposed Vienna classification of gastrointestinal epithelial neoplasia: (1) negative for neoplasia/dysplasia, (2) indefinite for neoplasia/dysplasia, (3) non-invasive low grade neoplasia (low grade adenoma/dysplasia), (4) non-invasive high grade neoplasia (high grade adenoma/dysplasia, non-invasive carcinoma and suspicion of invasive carcinoma), and (5) invasive neoplasia (intramucosal carcinoma, submucosal carcinoma or beyond).

CONCLUSION

The differences between Western and Japanese pathologists in the diagnostic classification of gastrointestinal epithelial neoplastic lesions can be resolved largely by adopting the proposed terminology, which is based on cytological and architectural severity and invasion status.

Generation of T cells from adult human hematopoietic stem cells and progenitors in a fetal thymic organ culture system: stimulation by tumor necrosis factor-alpha

To investigate the T-lymphopoietic capacity of human adult bone marrow (ABM) hematopoietic progenitor cells, CD34+Lin-, CD34+CD38+, and CD34++CD38- cells were cultured in a severe combined immunodeficient (SCID) mouse fetal thymic organ culture (FTOC). Direct seeding of these progenitors resulted in a moderate to severe cell loss, particularly for the CD34++CD38- cell fraction, and T cells could only be generated from the CD34+Lin- fraction. Preincubation for 36 hours with interleukin-3 (IL-3) and stem cell factor (SCF) led to an improved cell survival and proliferation, although T-cell development was seen only in the CD34+Lin- fraction. Addition of tumor necrosis factor (TNF)-alpha to IL-3 + SCF-supplemented preincubation medium resulted in optimal cell survival, cell proliferation. and T-cell generation of all 3 cell fractions. The TNF-alpha effect resulted in an up-regulation of CD127 (ie, the IL-7 receptor alpha-chain) in a small subset of the CD34+ cells. No evidence could be generated to support the possibility that TNF-alpha inhibits a cell population that suppresses T-cell differentiation. A quantitatively different T-cell generation potency was still seen between the 3 subpopulations: CD34+Lin- (100% success rate) > CD34+CD38+ (66%) > CD34++CD38- (25%). These data contrast with our previous findings using fetal liver and cord blood progenitors, which readily differentiate into T-lymphocytes in FTOC, even without prestimulation with cytokines. Our results demonstrate that adult CD34++CD38- cells, known to contain hematopoietic stem cells, can differentiate into T-lymphocytes and that a significant difference exists in T-lymphopoietic activity of stem cells derived from ontogenetically different sources. (Blood. 2000;95:2806-2812)

Associations between cellular immune effector function, iron metabolism, and disease activity in patients with chronic hepatitis C virus infection

We studied the associations of macrophage activity, T-helper cell types 1 and 2 (Th-1/Th-2) responses, and iron status in 55 patients with hepatitis C virus (HCV)-related liver disease and 28 control patients with noninfectious liver disease. Serum concentrations of soluble tumor necrosis factor receptor type II (sTNFrec 75), a macrophage activation marker, were higher in cirrhotic than in noncirrhotic patients (P<.001) regardless of their HCV status, whereas levels of neopterin, interleukin (IL)-4 and IL-10 did not differ significantly. In HCV-positive patients, sTNFrec 75 levels and transferrin saturation (TfS) correlated positively with levels of aspartate transaminase (P<.001 for sTNFrec 75 and P=.028 for TfS) and alanine transaminase (P=.003 for sTNFrec 75 and P=.039 for TfS). Increased TfS correlated significantly with both advanced liver disease and a predominant Th-2 pattern in HCV patients. Our data suggest that an association exists between macrophage activation and hepatic dysfunction, and that iron status may affect the clinical course of HCV infection by modulating Th-1/Th-2 responses in vivo.

Bone marrow CD34 cells generate fewer T cells in vitro with increasing age and following chemotherapy

To assess the influence of high-dose chemotherapy and age on the intrinsic capacity of stem cells to generate T cells, CD34+ cells derived from bone marrow used in clinical transplantation were evaluated in an in vitro T-cell assay using a mouse thymic microenvironment. CD34+ cells were sorted from healthy donor and autologous back-up bone marrow after density gradient centrifugation and depletion for CD1, 3, 4, 7, 8, 19 and glycophorin A using magnetic beads. CD34+ cells were then introduced in day 14-15 fetal SCII) mouse thymus lobes by incubation in hanging drops for 48 h. After transfer to gelfoam rafts they were cultured for variable time periods. The lobes were then homogenized in a tissue grinder for flow cytometric analysis gating on human cells. These were evaluated for CD4, CD8, CD3 and HLA-DR surface expression. 51 samples were analysed and three patterns of T-cell precursor development could be observed. In pattern A no human cells could be recovered, in pattern B maturation stopped at the CD4+ CD8- CD3- pre-T-cell stage, and in pattern C maturation to double-positive CD4+ CD8+ thymocytes was reached. In 25 healthy donors under age 40 three showed pattern A, 12 pattern B and 10 pattern C, whereas in 16 healthy donors over the age 40 there were respectively four with A, seven with B and only five with C (P=0.01). In 10 patients who had previously received chemotherapy, none developed pattern C, five pattern B and five pattern A, in contrast to 15/41 pattern C, 19/41 pattern B and 7/41 pattern A in healthy donors. These data suggest an intrinsic loss of T-cell generation capacity from adult bone marrow stem cells in comparison to reports on stem cells of fetal origin. This loss correlated weakly with age, irrespective of thymic involution, and may be further reduced by prior chemotherapy.

In vitro intrathymic differentiation kinetics of human fetal liver CD34+CD38- progenitors reveals a phenotypically defined dendritic/T-NK precursor split

Human CD34+CD38- hematopoietic precursor cells from fetal liver are able to develop into T, NK, and dendritic cells in a hybrid human/mouse fetal thymic organ culture (FTOC). In this report, we pay particular attention to the early events in differentiation of these precursor cells. We show that the CD34+CD38- precursor cells, which are CD4-CD7-cyCD3-HLA-DR-/++ (cy, cytoplasmatic), differentiate into a CD4+ population that remained CD7-cyCD3-HLA-DR++ and a CD4- population that expressed CD7 and cyCD3. The CD4+CD7-cyCD3- cells differentiate into phenotypically and functionally mature dendritic cells, but do not differentiate into T or NK cells. The CD4-CD7+cyCD3+ population later differentiates into a CD4+CD7+cyCD3+HLA-DR- population, which has no potential to differentiate into dendritic cells but is able to differentiate into NK cells and gammadelta and alphabeta T lymphocytes. These findings support the notion that the T/NK split occurs downstream of the NK/dendritic split.

Two cases of disseminated mucormycosis in patients with hematological malignancies and literature review

Two cases of disseminated mucormycosis in patients with underlying hematological disease are described. Both patients presented with fever and pulmonary infiltrates which did not respond to empirical treatment with broad-spectrum antibiotics and antifungal agents, and in both patients there was rapid progression with a fatal outcome. All cultures were negative and the diagnosis was made postmortem. A review of the literature revealed only three recent reports of successful treatment of disseminated mucormycosis. Survival correlated with control of the underlying disease and early diagnosis based on histological examination of biopsy specimens from suspected lesions. Therapy consisted of surgical debridement and amphotericin B. Standard therapeutic schedules need to be defined for this infection.

Production of superoxide by human malignant melanoma cells

Metastasis is a complicated multi-step process involving interactions between tumour cells, the extracellular matrix and the vessel walls. Experimental observations suggest that leucocyte migration and function could be a suitable model in order to understand tumour cell dissemination. In the present report we show and quantify the production of free radicals by human malignant melanoma cells (St-ml12) by means of a spectrophotometrical method, using an enzyme immunoassay reader. Endothelial cells and activated polymorphonuclear leucocytes were used as controls. Melanoma cells without stimulants produced large amounts of superoxide anion at an increasing rate in relation to time, which could be inhibited by superoxide dismutase. Production of hydrogen peroxide was minimal. The endothelial cells produced a negligible amount, in contrast to the activated polymorphonuclear leucocytes, which released large quantities of both free radicals. A rapid assay to analyse the production of free radicals by tumour cells is presented here. Using this, we demonstrated that melanoma cells produce superoxide anions, supporting previous observations which implicate superoxide anion in the mechanism of metastasis.

The Hermansky-Pudlak syndrome

The Hermansky-Pudlak syndrome (HPS) associates oculocutaneous albinism with a haemorrhagic diathesis and the accumulation of ceroid-like material in different tissues. HPS is not an uncommon type of albinism as it was diagnosed in 13.5% (8/59) of our autosomal recessive albinos. These eight patients were evaluated ophthalmologically and haematologically. Apart from the symptoms caused by the albinism, accompanying signs vary from ecchymoses to life threatening haemorrhages and death by associated restrictive lung disease. Recognition of this syndrome by the ophthalmologist can be of major importance in this serious and eventually fatal disorder.

An EORTC multicentre prospective survey of invasive aspergillosis in haematological patients: diagnosis and therapeutic outcome. EORTC Invasive Fungal Infections Cooperative Group

OBJECTIVES

The EORTC Invasive Fungal Infections Cooperative Group (IFICG) conducted a prospective survey by questionnaire of all cases of invasive aspergillosis (IA) in cancer patients to ascertain current diagnostic and therapeutic approaches.

METHODS

All members of the IFICG were asked prospectively to complete a detailed questionnaire for each IA case identified in their institution over a 12-month period.

RESULTS

One hundred and thirty questionnaires were returned. All cases were independently evaluated (DWD & JC) and 123 were eligible. Cases came from 20 hospitals in eight countries and the number of cases per institution varied from 1-21. Acute myeloid leukaemia (AML) (60, 49%), acute lymphoblastic leukaemia (ALL) (21, 17%) and lymphoma (11, 9%) were the most frequent underlying diseases, and 16 (12%) patients had received an allogeneic bone marrow transplant. Pulmonary involvement was present in 87%, infection of sinuses/nose in 16% and brain in 8%. The chest radiograph was initially normal in 9% of those with primary pulmonary disease. The diagnosis was confirmed in 50%, probable in 31% and possible in 19%. The evidence for IA was on the basis of clinical and radiological features alone in 28%, with culture or histology in another 31% and 9%, respectively, and with both culture and histology in 29%. In three (2%) patients with diagnosis was based on culture or histology alone. Treatment was given to 120 patients (98%)-amphotericin B 75%, lipid-associated amphotericin B 36%, itraconazole 40%, flucytosine 12%, growth factors 33%, lobectomy 5%. At 3 months after diagnosis or first suspicion of IA, 44 (36%) patients were alive and 79 (64%) dead. Outcome was best in those with AML (30% death and 46% with a complete antifungal response or cure). Growth factors (mostly granulocyte colony stimulating factor) appeared not to influence outcome (P = 0.99).

CONCLUSION

IA remains a considerable diagnostic and therapeutic challenge. No single diagnostic procedure was universally successful and a multifaceted approach including surgery is necessary. There was no discernable difference in outcome between initial therapy with amphotericin B, itraconazole or lipid-associated amphotericin B, although numbers are limited and the study was retrospective.

[Diagnosis in chronic inflammatory bowel diseases--report of the Austrian Chronic Inflammatory Bowel Disease Study Group]

Diagnostic procedures in inflammatory bowel diseases (IBD) serve to secure the diagnosis and to optimize treatment. Upon initial diagnosis endoscopy up to the terminal ileum is mandatory including multiple step biopsies. When diagnostic guidelines are followed and adequate clinical information is available, IBD will be correctly classified in about 80 to 90% of cases upon first examination. In contrast endoscopic studies are only of limited value in monitoring treatment. The decision if and when to perform endoscopy during exacerbation of disease must be an individual one. When disease activity is evaluated, a distinction must be made between degree of activity as reflected by laboratory parameters and severity of illness as reflected by the clinical presentation with abdominal complaints, fistulas, abscesses, etc. Distinct activity indices are useful in clinical studies to obtain an objective evaluation of activity and severity of disease. At clinical routine visits questions should not only concern the basic illness but also ask for quality of life and psychosocial status. Only a small number of laboratory tests are needed for basic diagnosis and follow-up. A small bowel enteroclysis should always be performed upon primary diagnosis of Crohn's disease and during the course of disease when there is suspicion of small-bowel involvement. Double contrast barium enema should be limited to special indications as incomplete colonoscopy e.g. due to stenosis or suspected fistula. Sonography is the primary investigation when complications are suspected. CT is useful as an adjunct or when the afore mentioned methods do not show clear findings. NMR is the procedure of choice for detection of pararectal fistulas and abscesses. Transrectal endosonography is comparably good but limited to the experience of the investigators and by patient's tolerability.

Endosonographic image of a retrorectal bowel duplication: report of a case

PURPOSE

Endosonographic image and surgical therapy of a retrorectal bowel duplication are described.

METHODS, RESULTS, AND CONCLUSIONS

Compared with standard investigations, the most accurate information about a retrorectal mass in a 35-year-old woman could be obtained by means of endorectal ultrasound. Guided by endorectal ultrasound, the mass was excised using a transanal-transrectal approach, and Kraske's operation could be avoided. Additionally, histopathologic analysis of this rare disease is presented.

The role of interleukin-7 in early T-cell development

Interleukin-7 (IL-7) is a non redundant cytokine in thymic T-cell development. It binds to a dimeric receptor consisting of a specific IL-7Ralpha and a gamma-common subunit that it shares with the receptors for IL-2, 4, 9, 13 and 15. IL-7 is critical for early T-cell development but it also acts on immature B-cells and mature T-cells, and leads to secondary cytokine release. Its mechanisms of action in early T-cell development may be multiple. There is direct evidence to support a mechanistic involvement in TCR-gamma rearrangement that drives further TCR-gammadelta thymocyte commitment and maturation. There is indirect evidence for a role of IL-7 in TCR-beta rearrangement. It may however also act as a survival factor for TCR-beta rearranging thymocytes while the critical commitment selections are effected by other factors. The effects of IL-7 in fetal thymus organ culture are dose dependent, with a biphasic response: low doses of IL-7 are necessary for normal TCR-alphabeta thymocyte development but high doses block TCR-alphabeta maturation in favor of TCR-gammadelta development. A good understanding of the dose response of IL-7 in thymocyte development, mature T-cell stimulation, and of the release of secondary cytokines will be important for planning successful clinical trials with IL-7.

Impact of previous aspergillosis on the outcome of bone marrow transplantation

A retrospective analysis of 48 patients with documented or probable invasive aspergillosis (IA) prior to bone marrow transplantation (BMT) was conducted in 16 centers. Treatment of primary IA was medical in all 48 patients and surgical in 20; clinicoradiological resolution of IA occurred in 30 of 48 patients. Pretransplantation risk factors for relapse IA, total mortality, and IA-related mortality were analyzed by multivariate logistic regression with the following dichotomous risk factors: surgery as part of the initial treatment, resolution of IA by the time of BMT, donor type, conditioning regiment, total-body irradiation, T cell depletion, immunosuppressive therapy, type of antifungal prophylaxis, and growth factor prophylaxis. Conditioning with busulfan/cyclophosphamide was associated with a beneficial outcome for total survival and reduced IA-related mortality. Posttransplantation risk factors such as the development of graft-vs.-host disease (GVHD), therapy for GVHD, and the duration of neutropenia did not have a significant effect on relapse IA, IA-related mortality, or total mortality. The overall incidence of relapse IA was lower than expected (33% [16 of 48 patients]), but the mortality rate among relapsed patients was 88% (14 of 16). Patients receiving prophylaxis with absorbable or intravenous antifungals had less relapses of IA than did those not receiving prophylaxis (12 of 41 vs. four of seven, respectively). This finding reflects the need for better prophylaxis and new antifungal treatments for patients undergoing BMT who have a history of IA.

Nuclear translocation of mutagenized forms of human cytomegalovirus glycoprotein B (gpUL55)

To define structural elements involved in translocation of human cytomegalovirus (HCMV) glycoprotein B (gB) to the inner nuclear membrane (INM) compartment, mutagenized gB derivatives with deletions of the potential membrane anchor domains or of portions of the cytoplasmic tail were stably expressed in human astrocytoma cells. Subcellular localization examined by immunofluorescence and cell fractionation suggested that all gB derivatives reached the INM; however, reduced amounts were found after deletion of the extreme carboxy terminus [amino acids 856-906; gB(Del3)]. Pulse-chase analysis revealed accumulation in nuclear fractions of all gB derivatives during the chase, except for gB(Del3), which exhibited impaired nuclear retention. A carboxy-terminal nucleoplasmin-like signal localized within the respective deletion may thus be involved in nuclear transport and retention of HCMV gB. Immunoprecipitation after 32P-radiolabelling of the gB transfectants verified that the gB molecule is phosphorylated at a carboxy-terminal consensus motif for casein kinase II.

Phenotypic and functional maturation of TCR gammadelta cells in the human thymus

In contrast to thymic differentiation of TCR alphabeta cells, differentiation stages of TCR gammadelta cells are largely unknown. This report shows that CD1, a known marker of immature TCR alphabeta thymocytes, was expressed on some postnatal TCR gammadelta thymocytes. Only CD1+ TCR gammadelta thymocytes expressed recombination-activating gene-1 mRNA, and they were shown to differentiate into CD1- TCR gammadelta thymocytes. Functionally, sorted CD1- TCR gammadelta thymocytes proliferated in the presence of immobilized anti-CD3 Ab plus exogenous rIL-2 or rIL-15. Interestingly, in contrast to CD1- TCR alphabeta cells, CD1- TCR gammadelta thymocytes also proliferated extensively when cultured with exogenous rIL-2 or rIL-15 alone. FACS analysis as well as reverse transcription-PCR analysis showed that only CD1- TCR gammadelta thymocytes expressed IL-2Rbeta protein and mRNA. The differential expression of maturation markers, such as CD27, CD45RO, and CD45RA, as a function of expression of CD1 was similar in TCR gammadelta and TCR alphabeta thymocytes. An important exception is the expression of CD4 and CD8. Whereas TCR alphabeta thymocytes are mainly CD4-CD8 double positive at the immature CD1+ stage and CD4 or CD8 single positive at the mature CD1- stage, CD1(bright) TCR gammadelta thymocytes all expressed CD4, but only some of them expressed CD8. Some CD1- TCR gammadelta thymocytes also expressed CD8, but were negative for CD4. Collectively, our data clearly show that CD1 is a useful marker to distinguish immature human TCR gammadelta thymocytes from functional mature gammadelta cells based on recombination-activating gene-1 expression, in vitro differentiation, and phenotypic and functional characteristics.

Phenotypic and functional maturation of TCR gammadelta cells in the human thymus

In contrast to thymic differentiation of TCR alphabeta cells, differentiation stages of TCR gammadelta cells are largely unknown. This report shows that CD1, a known marker of immature TCR alphabeta thymocytes, was expressed on some postnatal TCR gammadelta thymocytes. Only CD1+ TCR gammadelta thymocytes expressed recombination-activating gene-1 mRNA, and they were shown to differentiate into CD1- TCR gammadelta thymocytes. Functionally, sorted CD1- TCR gammadelta thymocytes proliferated in the presence of immobilized anti-CD3 Ab plus exogenous rIL-2 or rIL-15. Interestingly, in contrast to CD1- TCR alphabeta cells, CD1- TCR gammadelta thymocytes also proliferated extensively when cultured with exogenous rIL-2 or rIL-15 alone. FACS analysis as well as reverse transcription-PCR analysis showed that only CD1- TCR gammadelta thymocytes expressed IL-2Rbeta protein and mRNA. The differential expression of maturation markers, such as CD27, CD45RO, and CD45RA, as a function of expression of CD1 was similar in TCR gammadelta and TCR alphabeta thymocytes. An important exception is the expression of CD4 and CD8. Whereas TCR alphabeta thymocytes are mainly CD4-CD8 double positive at the immature CD1+ stage and CD4 or CD8 single positive at the mature CD1- stage, CD1(bright) TCR gammadelta thymocytes all expressed CD4, but only some of them expressed CD8. Some CD1- TCR gammadelta thymocytes also expressed CD8, but were negative for CD4. Collectively, our data clearly show that CD1 is a useful marker to distinguish immature human TCR gammadelta thymocytes from functional mature gammadelta cells based on recombination-activating gene-1 expression, in vitro differentiation, and phenotypic and functional characteristics.

Hematopoietic growth factors in cancer patients with invasive fungal infections

Hematopoietic growth factors have been used in prophylaxis and treatment of neutropenic febrile episodes. Granulocyte colony-stimulating factor (G-CSF) and granulocyte macrophage colony-stimulating factor (GM-CSF) are the most common growth factors in clinical use. Both successfully shorten the duration of neutropenia following myelo-suppressive or myeloablative chemotherapy. The influence of G-CSF and GM-CSF on documented infections and mortality from infections is less obvious. There is no clear evidence that treatment with growth factors reduces the incidence of fungal infections. Since mortality is not affected, considerations of morbidity and cost effectiveness currently dominate the indication for use of growth factors. At current costs, their use is indicated in prophylaxis when the likelihood of developing neutropenic febrile episodes following chemotherapy is 40% or more.

Mortality hazard functions as related to neutropenia at different times after marrow transplantation

We characterized the relationship between severe neutropenia and risk of death in 2,276 patients after marrow transplantation to define objective and clinically relevant criteria that could be used to judge the timing and potential value of interventions designed to improve survival in patients with delayed initial engraftment. Proportional hazard models were used to estimate the relative risk of death before day 100 among patients alive on any given day with an absolute neutrophil count (ANC) less than 100/microL compared with those alive on the same day with an ANC > or = 100/microL. Between day 10 and 14, the risk ratio remained close to 1.0, indicating that the risk of death before day 100 for patients with an ANC less than 100/microL was similar to that for patients with an ANC > or = 100/microL. Between day 15, when 38% of patients had an ANC less than 100/microL, and day 26, when 3.8% of patients had an ANC less than 100/microL, the risk ratio showed an overall upward trend, indicating that patients with an ANC less than 100/microL had a higher risk of death before day 100 than those with an ANC > or = 100/microL. Thereafter, the risk ratio fluctuated between 2.01 and 5.78, indicating consistently higher risks of mortality in patients with severe neutropenia. However, allogeneic and autologous transplant recipients each had distinctive risk ratio patterns. These results could be helpful in deciding the appropriate timing for treatment given to improve graft function after marrow transplantation.