Intensive immunoablation and autologous blood stem cell transplantation in patients with refractory rheumatoid arthritis: the University of Nebraska experience

Two patients with severe rheumatoid arthritis (RA) were treated with high dose chemotherapy and autologous blood stem cell transplantation. Hematopoietic stem cells mobilized readily with cyclophosphamide and granulocyte-colony stimulating factor. Both patients achieved an American College of Rheumatology (ACR) 50% response before starting high dose therapy. The transplantation regimen included 200 mg/kg cyclophosphamide and 6 doses of equine antithymocyte globulin. Transplantation was well tolerated and both patients recovered neutrophils on day 7 post-transplant. At one month post-transplant both patients had an ACR response of 80%. Both individuals relapsed at 6 months and responded well to a combination of disease modifying antirheumatic drugs that was previously ineffective. At 12 months ACR responses were 80% and 60%, respectively. The first patient developed a flare at 18 months when she was found to be hypothyroid; she regained an 80% ACR response at 24 months with therapy of hypothyroidism. The second patient progressed relentlessly 15 months post-transplant. Immunological reconstitution showed a continuous inversion of the ratio of CD4 and CD8 lymphocytes with a predominant expansion of memory T cells.

Decreased immune functions of blood cells following mobilization with granulocyte colony-stimulating factor: association with donor characteristics

In this study, mononuclear cells (MNCs) from granulocyte colony-stimulating factor (G-CSF)-mobilized blood stem cell (BSC) harvests from 104 healthy donors were analyzed for their immunological functions and compared with MNCs from 28 steady-state nonmobilized donors. The relationships between donor characteristics (age, gender, weight, and HLA type) and immune functions of the harvests were also analyzed. There was a significant (P <.01) decrease in natural killer and lymphokine-activated killer (LAK) cell-mediated cytotoxicity for G-CSF-mobilized effector cells compared with nonmobilized cells. Similarly, there was a significant (P <.005) decrease in both T-cell and B-cell mitogen response in G-CSF-mobilized cells compared with nonmobilized cells. There was dose-dependent inhibition of LAK cell-mediated cytotoxicity, but this effect was not seen with other immune function assays. Changes in immune function did not appear to be determined by frequency of cellular phenotypes or expression of effector function genes seen in a reverse-transcription polymerase chain reaction. There was a significant relationship between expression of certain HLA alleles (A1, A3, A24, B44, B62, DR15, DR17; all P <.01) and increased immune function, such as cytotoxicity and/or mitogen response. A decrease in immune function with the HLA-DR13 expression was also observed (P <.01). Since the G-CSF increases the number of MNCs, the increase in effector cells might compensate for decreased immune functions of these cells in vivo when transplanted into patients. These results suggest a decreased immune function in G-CSF-mobilized BSC harvests and warrant further studies to correlate these data with clinical outcome.

Full hematopoietic engraftment after allogeneic bone marrow transplantation without cytoreduction in a child with severe combined immunodeficiency

Bone marrow transplantation (BMT) for severe combined immunodeficiency (SCID) with human leukocyte antigen (HLA)-identical sibling donors but no pretransplantation cytoreduction results in T-lymphocyte engraftment and correction of immune dysfunction but not in full hematopoietic engraftment. A case of a 17-month-old girl with adenosine deaminase (ADA) deficiency SCID in whom full hematopoietic engraftment developed after BMT from her HLA-identical sister is reported. No myeloablative or immunosuppressive therapy or graft-versus-host disease (GVHD) prophylaxis was given. Mild acute and chronic GVHD developed, her B- and T-cell functions became reconstituted, and she is well almost 11 years after BMT. After BMT, repeated studies demonstrated: (1) Loss of a recipient-specific chromosomal marker in peripheral blood leukocytes (PBLs) and bone marrow, (2) conversion of recipient red blood cell antigens to donor type, (3) conversion of recipient T-cell, B-cell, and granulocyte lineages to donor origin by DNA analysis, and (4) increased ADA activity and metabolic correction in red blood cells and PBLs.

Ultrastructural heterogeneity of the alveolar macrophages from tobacco smokers with chronic bronchitis

Alveolar macrophages recovered by bronchoalveolar lavage from 14 heavy smokers with chronic bronchitis were assessed. Ultrastructural examination revealed marked cellular heterogeneity. Three subpopulations of alveolar macrophages were readily identifiable. These have been termed "young," "mature," and "degrading," reflecting their ultrastructural features. In addition, a majority of the cells were found to be positive by TUNEL staining, indicating DNA damage, but a very small percentage tested positive for Caspase-3, suggesting that apoptosis might not account for the DNA damage in at least some of these cells. A small percentage of proliferating cells were noted.

Pharmacokinetics and in vivo effects of a six-base phosphorothioate oligodeoxynucleotide with anticancer and hematopoietic activities in swine

A short phosphorothioate oligodeoxynucleotide telomere mimic with the sequence 5'-d(TTAGGG)-3', TAG-6, has been shown to inhibit telomerase activity and have antineoplastic and hematopoietic stimulatory properties. In this study, three immature male domestic swine (weighing approximately 40 kg) were administered 200 mg/m2 of TAG-6 by continuous intravascular infusion at rates of 0.48 +/- 0.07 mg/hr for 14 days to evaluate the pharmacokinetics, toxicity, and tissue distribution. There was considerable variability (both within each animal and across animals) observed in the pharmacokinetic data. The plasma half-life (t1/2 appeared to be short enough that it could be assumed that steady state was attained by at least 96 h after the start of the infusion. The t1/2 estimates for the three pigs were 8.96, 109, and 1.97 h (the long t1/2 for pig 2 may be explained by poor parameter estimation due to the variability). The volume of distribution ranged from 9.80 to 51.8 L (0.3-1.4 L/kg), and plasma clearance estimates ranged from 0.33 to 3.46 L/h (5.5-57.7 ml/min). The average plasma concentrations at steady state were 0.845, 0.933, and 0.178 microg/ml (0.44, 0.49, and 0.093 microM) for the three animals. Nearly 30% of the administered dose was cleared through renal excretion by day 7 postinfusion. The distribution of TAG-6 was primarily to the liver and kidney, but the spleen and thyroid accumulated relatively high concentrations of TAG-6. TAG-6 was metabolized to apparently higher molecular weight products, which were observed in the urine. The size periodicity of these apparently higher molecular weight products was in 6-base intervals, which is consistent with the actions of telomerase. The infusion did not produce significant changes in serum chemistry or circulating blood cells, but a decrease in colony-forming unit-granulocyte-monocyte (CFU-GM) colony formation from BM was observed. These data suggest that TAG-6 may be a very specific pharmacophore.

Two-colour flow-cytometric analysis of pulmonary alveolar macrophages from smokers

The study of alveolar macrophages (AM) from smokers by flow cytometry (FCM) has been limited by strong autofluorescence and the lack of reliable markers to identify macrophages. Crystal violet quenching was reported to be effective in reducing autofluorescence of AM. CD68 is a marker for macrophages in immunohistochemistry, but has been less useful in FCM because of poor surface expression. This study evaluated the effectiveness of a method for two-colour FCM analysis of AM combined with membrane permeabilization and crystal violet quenching. Bronchoalveolar lavage cells, fixed in 4% paraformaldehyde and permeabilized using 0.5% Triton X100, were incubated with fluorescent-labelled antibodies for 30 min and quenched with a saturated crystal violet solution. Two-colour FCM was then performed using forward/side scatter gating to select AM. Autofluorescence at 525 nm (fluorescein isothiocyanate) and 575 nm (phycoerythrin) markedly decreased after quenching. After permeabilization, 97.1+/-2.8% of the gated cells were CD68+, while 53.9+/-18.6% of the AM were positive without permeabilization. CD68+ cells were sorted and proved to be AM morphologically. Analysis of CD71 (transferrin receptor) expression by FCM correlated with immunocytochemistry (r=0.77, p<0.05). The permeabilization/quenching technique, therefore, represents a satisfactory means to evaluate alveolar macrophages by flow cytometry.

Antitumor activity of human umbilical cord blood cells: A comparative analysis with peripheral blood and bone marrow cells

Although the hematopoietic reconstituting ability of human umbilical cord blood cells (UCBC) is well documented, their antitumor cytotoxic potential has not been well studied. Therefore, UCBC were compared to normal peripheral blood stem cells (PBSC) and bone marrow (BM) stem cell harvests for cytomorphology, antitumor cytotoxic activity before and after ex vivo cytokine manipulation, response to T and B cell mitogens, expression of adhesion molecules and immunophenotypes using flow cytometry, cytokine production and in vivo antitumor activity. BM and PBSC, but not UCBC, did not form cellular clusters in culture. More cytotoxic granules were present in the cytoplasm of UCBC than PBSC following activation in vitro. Ex vivo manipulation of UCBC with cytokines produced more cytotoxicity to K562 and Raji tumor cells than PBSC or BM (p<0.001). Most cytotoxic cells in UCBC cultures were T lymphocytes, and a correlation existed between the number of CD56+ cells and cytotoxicity levels, particularly after in vitro activation with interleukin-2. No significant difference in adhesion molecule expression was noted among UCBC, PBSC and BM cells. However, there was a significantly decreased expression of CD54 molecules (ICAM) on UCBC compared to PBSC (p<0.05). IL-2 activated UCBC showed significant antitumor effects against K562 leukemic cells grown in SCID mice. Thus UCBC contained more antitumor effector cells and precursors than cells from marrow or peripheral blood cells which might be capable of providing a therapeutic effect.

Lymphoma cells associated with bone marrow stromal cells in culture exhibit altered growth and survival

The detection of clonal populations of lymphoma cells in histologically negative bone marrow using culture techniques is a predictor of poor outcome for patients undergoing high dose therapy and autologous transplantation. In positive cultures, lymphoma cells were observed as outgrowths in association with adherent stromal cells, whilst only stromal cells were observed in negative long-term cultures. This study developed an experimental model to further study the interactions occurring between lymphoma cells and stromal cells. Using random dot graticule analysis, 86% and 74%, respectively, of patient lymphoma cells grew in association with stromal cells in leukapheresis and bone marrow harvest cultures with the formation of cobblestone areas at sites of interaction between lymphoma cells and stromal cells. Secondary cultures showed that individual stromal cells were able to support the growth of a small number of lymphoma cells. Coculture of the human lymphoma cell lines with a murine bone marrow stromal cell line, MS-5 also resulted in the formation of cobblestone areas, which corresponded with the suppression of nonadherent cell production by the lymphoma cell lines. Upon interacting with MS-5 cells, the lymphoma cell lines formed pseudopodia and underwent pleiomorphic nuclear changes. Contiguous linear homotypic associations between lymphoma cells were evident, as opposed to focal contacts occurring in the heterotypic interactions between lymphoma cells and MS-5 cells. An increasing proportion of supernatant lymphoma cells underwent apoptosis as time in culture increased. These results demonstrate that bone marrow stromal cells alter the pattern of growth of lymphoma cells and may have an important role in the maintenance of occult lymphoma by inhibiting apoptosis.

Tissue factor and cell morphology variations in cell lines subcloned from U87-MG

Tissue factor is heterogeneously distributed within and among cells in cultures of U87-MG, a glioblastoma-derived line. The heterogeneity among cells may reflect the presence of distinct populations within the U87-MG cultures. This hypothesis has been confirmed by cloning of five distinct sublines from the parent population. These subpopulations have remained distinct through 4 months of growth in culture and one cycle of cryogenic preservation and thawing. The cultures differ in growth rates, amounts of tissue factor activity expressed, tissue factor antigen measured by flow cytometry, and patterns of tissue factor distribution studied by immunofluorescence microscopy. Characterization of these sublines allowed us to recognize that the tissue factor distribution on polarized cells (e.g. spindle-shaped) differed from that on cells with less polar morphologies. Finely speckled tissue factor staining tended to be localized to polarized aspects of the cell body where actin stress fibers are commonly present, whereas larger distinct foci of tissue factor were present in regions of membrane spreading. These results show that tissue factor is distributed differently in distinct regions of plasma membrane differentiation. Furthermore, the isolation of distinct stable subpopulations by dilutional cloning of U87-MG cultures serves as a reminder that cell culture heterogeneity can complicate experiments using molecular genetic manipulation of cultured cells which require clonal isolation of genetically altered lines.

Lymphocyte reconstitution after allogeneic blood stem cell transplantation for hematologic malignancies

Forty-one patients were studied at set times after allogeneic blood stem cell transplantation (alloBSCT) for recovery of lymphocyte numbers and function. Cells were mobilized with G-CSF from HLA-matched related donors and cryopreserved. Graft-versus-host disease (GVHD) prophylaxis consisted of cyclosporine and methotrexate; G-CSF was administered post-transplant. Median time to absolute lymphocyte count (ALC) >500/microl was 17 days vs 41 and 49 days in historical alloBMT patients with G-CSF (n = 23) or no cytokine (n = 29) post-transplant, respectively (P < 0.0001). CD4/CD8+ ratio was 1.9 on day 28 after alloBSCT, then gradually declined to 0.8 at 1 year due to more rapid CD8+ cell recovery. Mean phytohemagglutinin-induced T cell responses were lower than normal on day +28 (P < 0.05), then tended to recover towards normal values. Natural-killer cytotoxicity remained low from day +28 to 1 year post-alloBSCT, but considerable lymphokine-activated killer cytotoxicity was induced from cells already obtained on day +28. Faster lymphocyte recovery correlated with better survival in alloBSCT patients (median follow-up 287 days, P = 0.002), ALC recovery was not affected by acute GVHD, CMV infections or doses of infused cells. ALC recovery did not correlate with survival in either historical alloBMT group. These data suggest that after alloBSCT lymphocyte reconstitution is faster than after alloBMT, and that quicker lymphocyte recovery predicts better survival in the alloBSCT setting.

Comparison of molecular cytokeratin 19 reverse transcriptase polymerase chain reaction (CK19 RT-PCR) and immunocytochemical detection of micrometastatic breast cancer cells in hematopoietic harvests

Detection of small numbers of breast cancer cells in patient blood, aphereses, and bone marrow has become increasingly important as data have accumulated showing immunocytochemically (ICC) positive tumor cells in up to 50% of women with stage I and II breast cancer, who were initially thought to be cured of their disease but later relapsed. The ability to rule out the presence of micrometastatic disease at any stage of the clinical management protocol, whether before, during, or after therapy, would provide a useful monitoring and diagnostic tool for both the clinician and the scientist. Monitoring for the presence of minimal residual disease (MRD) is traditionally performed using ICC. A more recently established RT-PCR technique uses a molecular marker (the presence of the cytokeratin 19, CK19, transcript) to identify MRD in patient samples, with a level of sensitivity reported to be one tumor cell in 10(6) nucleated cells. This level of sensitivity is generally higher than that claimed for ICC. Based on the discriminating results of this first study, a number of laboratories have evaluated this technique for its diagnostic potential. Results from several laboratories showed a higher than expected false positive rate due to a variety of identified and unidentified sources. Therefore, the current study was designed to achieve two aims: to establish the level of sensitivity and specificity of the RT-PCR technique and to dissect out the possible variables that may contribute to a false positive result using this molecular approach. To accomplish the first goal, two simulation strategies were used, limited dilution of tumor cells into apheresis harvests and semi-quantitative PCR using stepwise dilutions of extracted RNA from tumor cells in apheresis harvests. The second goal was accomplished by performing sequential blood drawings with variably timed sample processing to identify some of the more common variables (time, anticoagulant, sample sequence) that may contribute to false positive results. Of three variables investigated, including type of blood preservative, sequence of blood tube collection, and time point of sample processing, each may contribute to a false positive result. In addition to these problems, known events involving illegitimate transcription of specific genes nonspecifically in tissue is also a potential source of false positive results. These issues may be further compounded by lack of attention to the more common methodologic problems encountered in any laboratory using the PCR technique. However, recommendations can be developed for the effective application of this technique, whose greatest strength is the demonstration of tumor negativity of the sample.

A hexameric phosphorothioate oligonucleotide telomerase inhibitor arrests growth of Burkitt's lymphoma cells in vitro and in vivo

A phosphorothioate oligonucleotide (PS-ODN) with sequence identical to the repeat sequence of the mammalian telomere, 5'-d(TTAGGG)-3', was incubated with a Burkitt's lymphoma-derived (OMA-BL1) cell line. This hexanucleotide inhibits telomerase activity in cell lysates, lengthens cell doubling time, and induces apoptosis. Concatenated repeats (12-, 18-, and 24-mers) of the 5'-d(TTAGGG)-3' motif induce similar cellular responses. Scrambled sequences do not efficiently inhibit telomerase activity or significantly alter cell growth and viability. The in vivo efficacy of this PS-ODN was evaluated in a xenograft human-nude mouse model. Once tumors were established these animals were administered the telomere mimic, 5'-d(TTAGGG)-3', a control scrambled sequence 5'-d(TGTGAG)-3', or saline for 14 days via a subcutaneous osmotic pumps in a blinded study monitoring tumor size with dose and time. A significant decrease in tumor size was observed in animals given 50 micrograms/mouse/day 5'-d(TTAGGG)-3', but not following 5'-d(TGTGAG)-3', relative to the saline-treated animals. The antitumor activity of the 6-mer telomere mimic demonstrated a dose dependency including a reduction in metastatic nodules in the spleen. No activity was observed with the scrambled controls. In addition to antitumor activity we observed an increase in the mouse hematopoietic progenitor cell populations, BFU-e and CFU-GM. These results demonstrated the effects of a short hexameric oligonucleotide telomere mimic in vitro and in vivo and the potential utility of short oligonucleotides as telomerase inhibitors.

Allogeneic-blood stem-cell collection following mobilization with low-dose granulocyte colony-stimulating factor

PURPOSE

The optimal dose of granulocyte colony-stimulating factor (G-CSF) for mobilization of allogeneic-blood stem cells (AlloBSC) has yet to be determined. As part of a prospective trial, 41 related human leukocyte antigen (HLA)-matched donors had blood cells mobilized with G-CSF at 5 micrograms/kg/d by subcutaneous administration. The purpose of this trial was to monitor adverse effects during G-CSF administration and stem-cell collection, to determine the optimal timing for stem-cell collection, and to determine the cellular composition of stem-cell products following G-CSF administration.

PATIENTS AND METHODS

The median donor age was 42 years. Apheresis began on day 4 of G-CSF administration. At least three daily 12-L apheresis collections were performed on each donor. A minimum of 1.0 x 10(6) CD34+ cells/kg (recipient weight) and 8.0 x 10(8) mononuclear cells/kg were collected from each donor. All collections were cryopreserved in 5% dimethyl sulfoxide and 6% hydroxyethyl starch.

RESULTS

Toxicities associated with G-CSF administration and the apheresis process included myalgias/arthralgias (83%), headache (44%), fever (27%), and chills (22%). The median baseline platelet count of 242 x 10(4)/ mL decreased to 221, 155, and 119 x 10(6)/mL on days 4, 5, and 6 of G-CSF administration, respectively. Median numbers of CD34+ cells in collections 1, 2, and 3 were 1.99, 2.52, and 3.13 x 10(6)/kg, respectively. The percentage and total number of CD4+, CD8+, and CD56+/CD3- cells remained relatively constant during the three collections. Median total numbers of cells were as follows: CD34+, 7.73 x 10(6)/kg; and lymphocytes, 6.93 x 10(8)/kg.

CONCLUSION

Relatively low doses of G-CSF can mobilize sufficient numbers of AlloBSC safely and efficiently.

Biochemical and functional characterization of soluble multivalent MHC L(d)/Fc gamma 1 and L(d)/Fc mu chimeric proteins loaded with specific peptides

Central to the specificity of the immune system is the interaction between the T cell receptor and the major histocompatibility complex (MHC)-peptide ligand complex. To better understand the nature of this interaction, and to investigate possible avenues for specific therapeutic intervention, we have produced soluble recombinant molecules that can modulate antigen-specific T cells. Our approach involved the construction of recombinant murine genes composed of the MHC class I gene H-2L(d) and the Fc portion of immunoglobulin (Ig) heavy chain genes mu or gamma1. Stable transfectants of these L(d)/Fc gamma1 and L(d)/Fc mu genes generated correctly spliced transcripts and were capable of secreting chimeric protein. Immunoprecipitation analyses demonstrated the presence of chimeric L(d)/ Fc gamma1 and L(d)/Fc mu monomers of approximately 69 kDa and 90 kDa, respectively, as well as chimeric dimers under nonreducing conditions. The capacity of L(d)/Ig molecules to bind specific peptide ligands was demonstrated using radiolabeled peptides or with monoclonal reagents that specifically identify peptide-induced conformational changes in the L(d) ligand binding site. Soluble divalent L(d)/Fc gamma1 molecules were loaded with the murine cytomegalovirus-derived peptide and other L(d)-specific peptide ligands and subsequently isolated and purified. Peptide-loaded L(d)/Fc gamma1 molecules were capable of inhibiting the response of class I-restricted T cells in vitro in a peptide-specific fashion. The development of soluble multivalent chimeric proteins that possess unique properties of both the MHC class I and Ig molecules provides a valuable reagent for the study of potential mechanisms of in vitro and in vivo immune modulation.

Human immunodeficiency virus encephalitis in SCID mice

The human immunodeficiency virus (HIV) is neuroinvasive and commonly causes cognitive and motor deficits during the later stages of viral infection. (referred to as HIV dementia). The mechanism(s) for disease revolves around secretory products produced from immune-activated brain macrophages/microglia. Recently, we developed an animal model system for HIV dementia that contains xenografts of HIV-1-infected cells inoculated into brains of mice with severe combined immunodeficiency (SCID). This animal system was used to quantitatively evaluate HIV-induced neuropathology. Xenografts of HIV-1-infected human monocytes (placed into the putamen and cortex of SCID mice) remained viable for 5 weeks. HIV-1 p24 antigen expression in mouse brain was persistent. Progressive inflammatory responses (including astrogliosis and cytokine production), which began at 3 days, peaked at day 12. The range of astrocyte proliferative reactions exceeded the inoculation site by > 1000 microns. Brains with virus-infected monocytes showed a > or = 1.6-fold increase in glial fibrillary acidic protein (staining distribution and intensity) as compared with similarly inoculated brains with uninfected control monocytes. These findings paralleled the accumulation and activation of murine microglia (increased branching of cell processes, formation of microglial nodules, interleukin (IL)-1 beta and IL-6 expression). An inflammatory reaction of human monocytes (as defined by HLA-DR, IL-1 beta, IL-6, and tumor necrosis factor-alpha expression) and neuronal injury (apoptosis) also developed after virus-infected monocyte xenograft placement into mouse brain tissue. These data, taken together, demonstrate that this SCID mouse model of HIV-1 neuropathogenesis can reproduce key aspects of disease (virus-infected macrophages, astrocytosis, microglial activation, and neuronal damage). This model may serve as an important means for therapeutic development directed toward improving mental function in HIV-infected subjects with cognitive and motor dysfunction.

Fibroblasts restrict tissue factor from vesicles which form in response to low concentrations of detergent

Studies of tissue factor activity on fibroblasts have found that manifestation of the otherwise cryptic activity is evoked by Triton X-100 or octyl glucoside at concentrations that lyse the cells. Even though sublytic concentrations of the detergents extract membrane lipids into the soluble phase, they were without effect on tissue factor activity. Those experiments led us to conclude that either the fibroblasts maintain plasma membrane lipid asymmetry even as lipids are extracted by the detergents, up to the onset of lysis, or additional mechanisms for regulation of tissue factor specific activity were operative. Using phase contrast and immunofluorescent microscopy, we now show that at least one additional regulatory mechanism is indeed operative. In response to sublytic concentrations of octyl glucoside or Triton X-100, the cells release vesicles from which tissue factor antigen is excluded. Lytic concentrations of the detergents preclude this segregation, leaving only low amounts of tissue factor antigen associated with the adherent cytoskeletons. Two-color staining reveals marked tissue factor-actin filament co-localization, which implies the potential for cytoskeletal participation in the observed tissue factor segregation. We propose that tissue factor activity is indeed regulated by the phospholipids with which it is associated and the degree to which phosphatidylserine is available on the membrane surface, but the cells possess additional mechanisms by which the association of tissue factor with potentially procoagulant membrane domains is controlled.

Immunologic attributes of cytokine mobilized peripheral blood stem cells and recovery following transplantation

The immunologic attributes of cytokine mobilized peripheral blood stem cell (PSC) products (n = 52) and the resulting reconstitution of the hematopoietic and immunologic system following autologous transplantation were examined in a consecutive population of non-Hodgkin lymphoma (NHL), or solid tumor patients at the University of Nebraska Medical Center. Granulocyte-monocyte colony stimulating factor (GM-CSF)-mobilized PSC products had a high frequency of monocytes (31%) and bands (15%) as compared to normal peripheral blood (PB) cells. The phenotypic analysis of the mobilized PSC product revealed that they had normal levels of CD4+ cells, an increased frequency of CD8+ cells and a corresponding decrease in the CD4+:CD8+ cell ratio as compared to the peripheral blood leukocytes (PBL) of normal individuals. PSC products also had an increase in CD34+ cells as compared to PB. Natural killer (NK) and T cell activity in the PSC products were also lower than that observed in PB. Post-transplantation there was an accelerated reconstitution of NK-cell function in the PB as compared to T cell function (PHA (phytohemagglutinin) mitogenesis) which did not return to normal by day 100 post-transplantation. We also report for the first time high levels of an irradiation resistant suppressor cell activity in the PSC product and in the PB post-transplantation. There was also a concomitant increase in CD4-, CD8-, TCR alpha/beta+ cells (phenotypic homolog of 'natural suppressor' (NS) cells) in the PB post-transplantation. The number of months of prior chemotherapy correlated with PHA response but the NS activity and frequency of CD4-, CD8- and TCR alpha/beta+ cells did not. Further, cytokine mobilization and apheresis appears to contribute to the loss of PHA responsiveness and the increased levels of suppressor cell activity.

c-myc antisense oligodeoxyribonucleotides inhibit proliferation of non-small cell lung cancer

BACKGROUND

Mutation or deregulation of certain cellular genes (protooncogenes) results in expression of proteins that appear to promote malignant transformation. Human non-small cell lung cancer has been documented to express many such oncogenes including c-myc, bcl-2, and mutant p53. Antisense oligodeoxyribonucleotides (ASODN) complementary to these oncogenes were tested on three non-small cell lung cancer cell lines for their efficacy in inhibiting cellular proliferation and oncoprotein expression.

METHODS

Established non-small cell lung cancer cell lines A427, SKMES-1, and A549 were grown in the presence of ASODNs complementary to messenger RNA of c-myc, bcl-2, p53, or controls at 1 mumol/L or 10 mumol/L concentrations for 4 or 10 days. Cellular proliferation was measured by tritiated thymidine uptake. Flow cytometry was used to quantitate oncoprotein expression. Intranuclear ASODN uptake was documented by fluoresceine-tagged ASODNs.

RESULTS

Fluoresceine-tagged ASODNs were readily taken up by all cell lines. c-myc, as well as bcl-2 and p53 ASODNs, were found to inhibit proliferation of all cell lines significantly compared with controls, most notably in line A549 (40.1% +/- 7.1% of control, p = 0.000 with c-myc ASODN). Antisense c-myc reduced c-myc protein by as much as 71.3% in A427, although protein levels were only minimally reduced in the viable cells of the other lines.

CONCLUSIONS

c-myc ASODNs inhibit proliferation of non-small cell lung cancer cell lines as well as reduce c-myc protein expression. Antisense bcl-2 and p53 also cause similar growth inhibition. These results suggest a critical role for activation of these oncogenes in the growth of cultured lung cancer cells. Furthermore, the efficacy and rapid cellular uptake of ASODNs support the potential role of antisense targeting of oncogene expression for pharmacologic control of non-small cell lung cancer.

Effects of BCR-ABL antisense oligonucleotides (AS-ODN) on human chronic myeloid leukemic cells: AS-ODN as effective purging agents

We examined phosphorothioate oligodeoxyribonucleotides (ODNs) directed against bcr in exon 3 or exon 2, which are rearranged with exon 2 of abl (B3A2 and B2A2) at t(9;22) of chronic myelogenous leukemia (CML). Since these ODNs are designed to be CML cell specific, we studied their effects on the human CML cell line K562, which is known to have B3A2 rearrangement, and leukemic cells from patients, as well as normal hematopoietic stem cells in vitro. In vitro experiments were performed to determine a potential role of these two ODNs as ex vivo purging agents. Incubation of B3A2 antisense at 40, 80, and 120 micrograms/ml with K562 CML cells for 72 hours at 37 degrees C resulted in 44%, 56%, and 63% reduction of CFU-L as compared to controls. In contrast, B3A2 sense and B2A2 antisense had no significant growth inhibitory effect on K562 cells. Incubation of B3A2 and B2A2 antisense ODNs at concentration of 80 micrograms/ml at 37 degrees C for 36 hours with normal peripheral blood stem/progenitor cells (PBSC) resulted in 124% and 98% CFU-GM formation as compared to untreated controls, respectively. However, incubation of PBSC with B3A2 and B2A2 sense-ODNs resulted in a 22% and 44% reduction in CFU-GM, respectively. In order to determine the ex vivo purging effects of bcr-abl ODNs, the K562 cells were mixed with PBSC from normal donors at a ratio of 1:20 (CML:PBSC). The mixture of cells was then incubated with B3A2 antisense at 80 micrograms/ml for 36 hrs at 37 degrees C. After incubation, no CML cells were detected by fluorescence in situ hybridization (FISH) as compared to untreated controls. These results were confirmed by RT-PCR using bcr-abl primers and mRNA isolated from the mixture of cells. Further, these results support the hypothesis that bcr-abl antisense ODNs are potentially effective agents for ex vivo purging of autologous stem cells before transplantation to eliminate/reduce the burden of leukemic cells. No significant toxicity to normal hematopoietic stem/progenitor cell population by the bcr-abl antisense ODNs was observed. Although unanticipated reductions in normal hematopoietic progenitor cells (CFU-GM) were observed with sense ODNs, no reduction in CFU-GM was observed with unrelated phosphorothioate ODN controls.

X-linked lymphoproliferative disease: twenty-five years after the discovery

The X-linked lymphoproliferative disease (XLP), one of six described X-linked immunodeficiencies, stems from a mutation at Xq25 which renders males impotent to mount an effective immune response to the ubiquitous EBV. Purtilo, who first observed this disease in 1969, established a Registry in 1980 to serve as a worldwide resource for the diagnosis, treatment, and research of this condition. Since Purtilo's death in late 1992, the Registry and research unit have not only continued to function as a worldwide consultative service, but have contributed the following. First, the number of affected boys has continued to grow; some 272 among 80 kindreds have been identified. Second, some boys (10%) who inherit the mutated XLP gene are immunologically abnormal even before evidence of EBV exposure. Third, the search for the XLP gene has been narrowed to a small region on Xq25. Its identification is near at hand; once cloned, this gene may well illustrate how the body orchestrates the complex immune response to EBV. Therein lies the justification for the quest for this gene, not only for the benefit of the few surviving boys and those to be born to female carriers, but also for defining its role in defending the body against a ubiquitous DNA virus.

Functional and phenotypic characterization of human peripheral blood stem cell harvests: a comparative analysis of cells from consecutive collections

A considerable number of patients with malignancies who are treated with high-dose therapy and hematopoietic stem cell transplantation subsequently relapse. Analyses of peripheral blood stem cell (PBSC) harvests obtained from 49 cancer patients showed that the PBSC harvest contained precursors for antitumor effector cells. Ex vivo manipulation of these harvests to maximize the antitumor effector cell activity may provide a new therapeutic approach to decrease or eliminate any minimal residual disease that remains after high-dose therapy. Characterization of PBSC from consecutive collections determined the collections best suited for ex vivo augmentation of antitumor cytotoxic effector cells. We report the results of a functional and phenotypical characterization of PBSC obtained from six consecutive collections from 18 cancer patients receiving granulocyte-macrophage colony-stimulating factor (GM-CSF) for hematopoietic stem/progenitor cell mobilization. The PBSC were evaluated for their cytotoxicity using the 51Cr-release assay. The frequency and subsets of lymphocytes were determined using flow cytometry with appropriate specific marker antibodies and differential cell counts. The content of hematopoietic progenitor cells in each collection was determined using a colony-forming unit granulocyte-macrophage (CFU-GM) culture assay. The frequency of cytotoxic effector cells including lymphokine-activated killer (LAK) cell precursors and lymphocytes was significantly greater (P < .05) in the early collections, whereas the later collections contained significantly (P < .05) more CFU-GM progenitor cells and fewer cytotoxic effector cells. Thus, our results show that PBSC obtained from advanced cancer patients do contain considerable levels of precursor cells for the generation of LAK cell populations. These results suggest that cells from the earlier collections are best suited for ex vivo manipulation to augment the antitumor effects.

Fibroblast tissue factor: calcium and ionophore induce shape changes, release of membrane vesicles, and redistribution of tissue factor antigen in addition to increased procoagulant activity

The coagulant activity of tissue factor (TF) in the membranes of cultured cells is increased after physical disruption of the cells, and a similar increase can be elicited by treatment of cell cultures with calcium ionophore and calcium. We observed that the supernatants of cultures treated with calcium and ionophore 4-Br-A23187 contained more TF activity than those of control cultures. Phase contrast microscopy showed that cultures treated with ionophore and calcium contained rounded cells, membrane vesicles, and cell fragments. Laser-activated fluorescence microscopy of cells stained for tissue factor antigen showed that 4-Br-A23187, in the presence of 5 mmol/L calcium, caused progressive changes in cell morphology. Treatment of cultures with thrombin receptor agonist peptide caused a transient increase in cytoplasmic calcium, but had no short-term effect on TF activity or cell morphology. These combined results show that 4-Br-A23187, with extracellular calcium, increases TF activity concomitant with dramatic changes in cell morphology and the plasma membrane. The effect of increased cytoplasmic calcium on TF expression may therefore be similar in mechanism to other models of cell injury and may be caused by the effects of a sustained increase of cytosolic calcium on cellular elements that influence membrane stability and the distribution of TF per se.

The leukemic myeloid cell line OMA-AML-1: an in vitro model of hematopoietic cell differentiation

The OMA-AML-1, acute myelogenous leukemia cell line is unique in that it spontaneously maintains both a CD34+ precursor cell compartment and a CD15+ differentiating cell compartment in vitro. A third transitional cell type with co-expression of CD34 and CD15 can also be identified in in vitro cultures. The cell line shows dynamic fluctuations in the relative sizes of these three cell compartments in suspension culture. In contrast, OMA-AML-1 fails to show phenotypic or morphologic evidence of differentiation when grown subcutaneously in immunodeficient mice. OMA-AML-1 responds to a number of hematopoietic cytokines. Delineation of cytokine responses on FACS isolated populations of CD34+ versus CD15+ cells demonstrated that proliferative responses occurred primarily at the level of the precursor cell (CD34+) while the production of endstage eosinophils occurred within the CD15+ compartment. OMA-AML-1 mimics a number of features of normal hematopoiesis and is proving to be a useful in vitro model for the study of hematopoietic differentiation.

HIV-1 rev antisense phosphorothioate oligonucleotide binding to human mononuclear cells is cell type specific and inducible

A fluorescein-conjugated, antisense phosphorothioate oligonucleotide with specificity for HIV-1 rev sequence (FAM-anti-rev) was investigated for its ability to bind to specific subsets of human peripheral blood mononuclear cells. Oligonucleotide binding by CD4+ and CD8+ T cells, B cells, and monocytes isolated from 15 normal and 15 HIV-infected individuals was evaluated on both nonstimulated mononuclear cells and after 24-hr activation with phytohemagglutinin (PHA). In both normals and HIV-infected individuals, we found a significantly higher percentage of monocytes and B cells binding oligonucleotide in comparison to T cells. Oligonucleotide binding by both T cells and B cells was enhanced by 24-hr PHA stimulation while monocyte uptake was unchanged. In comparison to normal controls, HIV-1-infected patients showed slightly higher percentages of both unstimulated and PHA activated CD4+, CD8+, and CD25+ T cells binding oligonucleotide. The propensity for a high percentage of monocytes, which may act as an HIV-1 reservoir, to bind the anti-rev oligonucleotide and the enhanced binding by T cells in the HIV-1-infected patient samples provides some optimism for potential in vivo therapy of HIV-1 infection using antisense oligonucleotides.

Selective cytotoxicity to human leukemic myeloblasts produced by oligodeoxyribonucleotide phosphorothioates complementary to p53 nucleotide sequences

Cells were treated in vitro with oligodeoxyribonucleotide phosphorothioates (ODNs) complementary to sites common to both wild-type and mutant p53 nucleotide sequences. Acute myelogenous leukemia (AML) blasts from peripheral blood were exposed to four different p53 ODNs and showed anti-leukemic effects in suspension culture. This effect continued after removal of the ODN from the medium. Blocking of self-renewal of the leukemic blast stem cells in secondary plating of cells from cloning assays by two of the p53 ODNs was also observed. Control ODNs had no effect on leukemic blasts. Treatment of normal bone marrow cells with the four p53 ODNs did not influence their growth, nor was there any effect by the p53 ODNs on the leukemic cell-line, HL60, that does not express p53. These data suggest that p53 ODNs are selectively toxic to primary myelogenous blasts and may be therapeutically useful in AML.

Monocyte tissue factor in treated Hodgkin's disease

Thrombosis is a recognized complication of Hodgkin's disease. The mechanism for thrombosis in this setting is not known. We determined the functional expression of tissue factor on peripheral blood monocytes in 14 consecutive patients with relapsed Hodgkin's disease. Marked elevations in activity were present in slightly more than half of the subjects. Tissue factor activities varied over 75-fold. Patients with higher tissue factor levels tended to be males who had not undergone splenectomy as part of their staging evaluation. Definite thrombotic complications occurred in three of the patients with the highest levels of tissue factor. While monocyte tissue factor may play a contributory role in the development of thrombotic complications in some patients with relapsed Hodgkin's disease, marked elevation of tissue factor is characteristic of only a subpopulation of these patients. This suggests that patient-, therapy- or disease-specific variables, including tissue factor, may determine the development of thrombosis in these patients.

Immunofluorescent studies of tissue factor on U87MG cells: evidence for non-uniform distribution

U87MG cells (human glioblastoma) express tissue factor and shed membrane-derived vesicles enriched in procoagulant activity. Tissue factor antigen has been studied by flow cytometry, immunofluorescent microscopy and Western blotting. Flow cytometric analysis utilized monoclonal antibodies recognizing the tissue factor extracellular domain and the carboxyl-terminal nine amino acids. Studies with intact and permeabilized cells support the location of the carboxyl-terminal domain in the cytoplasm, as previously predicted from the protein sequence. Immunofluorescent microscopy revealed a heterogeneous staining pattern, indicating that tissue factor antigen may be clustered on the cell surface. Intense staining was occasionally observed in cytoplasmic extensions and membrane regions that appeared to be extruding from the cells. Western blot analysis of vesicles shed into the culture medium revealed a principal tissue factor band with mobility marginally slower than that of placental tissue factor. Both extracellular and cytoplasmic epitopes were present in this vesicular tissue factor.

Clinical and immunologic studies in reticular erythematous mucinosis and Jessner's lymphocytic infiltrate of skin

BACKGROUND

Little is understood about reticular erythematous mucinosis and Jessner's lymphocytic infiltrate of skin.

OBJECTIVE

Our purpose was to define reticular erythematous mucinosis and Jessner's lymphocytic infiltrate of skin further with focus on immunologic studies.

METHODS

In patients with reticular erythematous mucinosis and Jessner's lymphocytic infiltrate of skin, we measured circulating immune complexes before, during, and after therapy. We examined natural killer cells in a functional assay; we performed direct immunofluorescence and T- and B-cell marker studies in skin biopsy specimens.

RESULTS

The infiltrate in reticular erythematous mucinosis is composed of helper T cells. Circulating immune complexes are increased in both reticular erythematous mucinosis and Jessner's lymphocytic infiltrate of skin and decrease with hydroxychloroquine therapy and clinical clearing. Natural killer cell function is decreased in reticular erythematous mucinosis and Jessner's lymphocytic infiltrate of skin.

CONCLUSION

Changes in circulating immune complex titers accompanying therapy with hydroxychloroquine and clinical clearing, with recurrence of the condition and increase in circulating immune complexes on discontinuation of treatment, point to a possible relation between these events.

Flow cytometric analysis of posterior oropharyngeal tumors

To date, few studies have evaluated the diagnostic and prognostic potential of flow cytometry in oropharyngeal tumors. The purpose of this study was to evaluate the interrelationship of anatomic location with the cytogenetic and cytokinetic characteristics of squamous cell carcinomas of the posterior oropharynx. Forty-eight paraffin-embedded squamous cell carcinoma specimens from the posterior oropharynx in clinical stages I to IV were analyzed with an Epics-C flow cytometer (Coulter Diagnostics, Hialeah, FL). Histopathologic grading was performed by the same pathologist, based on tumor differentiation. Of the 38 specimens suitable for analysis, several correlations were noted. First, as the %S-phase increased, the clinical stage increased. Second, as the histologic grade increased, the aneuploid frequency increased. Finally, as the tumor size increased, the histologic grade increased. From the results of this study, it was concluded that %S-phase may be useful in assessing the prognosis of squamous cell carcinomas of the posterior oropharynx. DNA index or aneuploid frequency, also may have value as a prognostic indicator. Finally, the lack of correlation between TNM staging and histologic grading stems not from tumor size but from nodal and metastatic involvement. Further studies are warranted to better define the usefulness of flow cytometric analysis in squamous cell carcinomas of the oropharyngeal region.

Systemic administration of a phosphorothioate oligonucleotide with a sequence complementary to p53 for acute myelogenous leukemia and myelodysplastic syndrome: initial results of a phase I trial

A synthetic phosphorothioate oligonucleotide was administered systemically to five patients with either relapsed or refractory acute myelogenous leukemia (AML), or myelodysplastic syndrome (MDS). Patients received a 10-day continuous intravenous infusion of this compound, which is complementary to p53 mRNA. No major toxicity attributable to a dose of 0.05 mg/kg/hr was observed. A range of approximately 9 to 18% of the administered dose was recovered in the urine as intact oligonucleotide. Evaluation of malignant cells recovered from bone marrow and peripheral blood at intervals before, during, and after treatment reveals no enhanced growth potential following oligonucleotide administration. Hence, a phosphorothioate oligonucleotide complementary to p53 mRNA can be administered at this dose level to humans without major toxicity. Higher doses need to be evaluated for toxicity and potential clinical efficacy.

Characterization of clonality of Epstein-Barr virus-induced human B lymphoproliferative disease in mice with severe combined immunodeficiency

To improve the diagnostic accuracy and understanding of the pathogenesis of lymphoproliferative diseases (LPDs) occurring in immunosuppressed transplant recipients (post-transplantation LPD), clonality of Epstein-Barr virus-induced human LPDs in mice with severe combined immunodeficiency was examined by analyzing: 1) human immunoglobulin genes and their products, 2) the clonality of Epstein-Barr virus DNA, and 3) genetic alteration of c-myc or bcl-2 genes. A spectrum of clonality was found in the LPDs comparable with that reported for post-transplantation LPDs, although rearrangements of c-myc or bcl-2 genes were not detected. It is confirmed that this system is useful in terms of clonality for understanding the early phases in the pathogenesis of post-transplantation LPD or LPD in immune deficient patients.

OMA-AML-1: a leukemic myeloid cell line with CD34+ progenitor and CD15+ spontaneously differentiating cell compartments

OMA-AML-1 was established from a patient with acute myelomonocytic (M4) leukemia at fifth relapse when blasts were greater than 85% CD34+, CD15-. Leukemic cells were established in suspension culture and independently grown as subcutaneous tumors in SCID mice. Cells growing in suspension culture underwent differentiation by phenotypic and morphologic criteria. In contrast, cells grown as subcutaneous solid tumors in SCID mice maintained progenitor cell characteristics with high-density CD34 expression and lack of morphologic differentiation. A tendency toward differentiation to CD15+, CD34- cells in vitro and self-renewal of CD34+, CD15- cells in vivo was consistently demonstrated regardless of whether cells were initially grown in vitro or in vivo. The cell line maintains both a CD34+, CD15- progentitor cell pool and a non-overlapping, CD15+, CD34- differentiating cell compartment after more than 1 year in continuous culture. Cell cycle analysis and cloning experiments were consistent with terminal differentiation occurring in the CD15+, CD34- population. The cell line shows concentration-dependent proliferative responses to interleukin (IL)-3, granulocyte-macrophage colony-stimulating factor (GM-CSF), and IL-6, but not to granulocyte CSF (G-CSF). OMA-AML-1 appears to mimic several features of normal myeloid hematopoiesis and should prove useful for the study of normal and malignant myeloid differentiation.

Hemagglutination and graft-versus-host disease in the severe combined immunodeficiency mouse lymphoproliferative disease model

In the course of evaluating the severe combined immunodeficiency mouse-human peripheral blood lymphocyte (SCID-PBL) model of lymphoproliferative disease, we noted hemagglutination occurring in peripheral blood smears of mice with serum human immunoglobulin levels greater than 1.0 mg/ml. The hemagglutinating process was mediated by human anti-mouse red cell antibodies of the IgM class, peaked at five to seven weeks post-transfer of 5 to 7 x 10(7) human PBL and was generally self limiting. However, death resulted in some mice when serum immunoglobulin levels were greater than 3.0 mg/ml. The most severely affected mice had hemagglutination induced congestion of liver, lungs and spleen. Several mice also had lesions consistent with graft-versus-host disease (GVHD) including focal hepatic necrosis and destruction of mouse splenic hematopoietic elements. The lesions associated with hemagglutination and GVHD in SCID-PBL mice are distinct from those associated with EBV-induced lymphoproliferation. Recognition of these pathologic processes are required for a thorough understanding of the SCID-PBL model.

Hematopathologic features of Epstein-Barr virus-induced human B-lymphoproliferation in mice with severe combined immunodeficiency. A model of lymphoproliferative diseases in immunocompromised patients

The anatomical distribution, morphology, and clonality, of 'non-Hodgkin's lymphomas' in immunocompromised patients are usually distinctly different from NHL occurring in the general population. Mosier DE, Gulizia RJ, Baird SM, Wilson DB: Nature (London) 335:256, 1988 have described lymphoproliferative disease (LPD) of human B cell origin in mice with severe combined immunodeficiency (scid mice) after transfer of human peripheral blood mononuclear cells from Epstein-Barr virus-seropositive individuals. Reported herein is detailed information regarding the morphology, phenotypes, and clonality of LPD lesions in 10 of 18 scid mice that had developed LPD after transfer of peripheral blood mononuclear cells. These lesions were diffuse and monomorphic proliferations of immunoblastoid cells. They were invasive in their growth and often necrotic. Human B cell-related and activation-associated antigens were found on the LPD lesions, although the numbers of cells with the latter antigens were relatively small. Immunofixation electrophoresis for human immunoglobulins in sera of the majority of mice revealed oligoclonal populations, however, phenotypic and cytogenetic analyses showed no definite monoclonality. This scid mouse model is beneficial for understanding the early phases in the pathogenesis of LPD in immunocompromised patients.

Characterization of a newly established human Burkitt's lymphoma cell line, OMA-BL-1

Using culture techniques, we have been able to grow occult tumor cells from the bone marrow from cancer patients and have developed a new malignant lymphoid cell line, OMA-BL-1, from the bone marrow of a 17-year-old patient with recurrent Burkitt's lymphoma. The tumor cells grew rapidly in vitro in suspension culture, and very aggressively in vivo in athymic nude mice with metastases to the liver and abdominal cavity. The morphological, chromosomal, immunophenotypic and molecular biologic characteristics of fresh uncultured tumor cells from the patient and tumor cells grown in culture and in athymic nude mice were very similar. The cells were positive for Epstein-Barr virus-associated nuclear antigens (EBNA) and chromosome analysis of the cells revealed an atypical chromosomal abnormality of 45,X,-X,i(8q), HSR(18)(q21),t(8;14)(q24;q32). Southern analysis demonstrated that c-myc was rearranged and amplified in these cells. Immunophenotypic analysis of the cells using flow cytometry showed monoclonal B cells expressing a surface IgG-kappa isotype. The tumor cells grown in nude mice had a significant decrease in CD24 expression when compared to cultured tumor cells. Electron microscopy of the fresh and cultured cells revealed Herpes virus, most likely Epstein-Barr virus, particles. This cell line has been maintained in culture for over 18 months. The aggressive growth and metastatic properties of this cell line in athymic nude mice make it a potentially useful experimental model to study the biology of human lymphoma.

SCID mouse model of Epstein-Barr virus-induced lymphomagenesis of immunodeficient humans

Immunodeficient humans are at very high risk of developing Epstein-Barr virus (EBV)-induced lymphomagenesis. Severe combined immunodeficient mice (SCID) have been shown to develop lymphoproliferative disease (LPD) following transfer of peripheral blood leukocytes (PBL) with latent EBV. To study mechanisms of lymphomagenesis, we compared results of engraftment of PBL from normal donors and immunodeficient donors with X-linked lymphoproliferative disease (XLP). Graft-versus-host disease (GVHD) developed in 6 of 10 SCID mice 4 to 8 weeks following transfer of PBL from normal donors. In contrast, none of 9 mice engrafted with PBL from XLP patients with T-cell defects showed GVHD. LPD developed in mice regardless of the immune competence of the donors. The expression of EBV-encoded proteins, results of immunophenotyping, and karyotyping of the LPD lesions revealed lethal oligoclonal LPD owing to transfer of latent EBV in B cells in mice engrafted with PBL from seropositive donors. Polyclonal LDP developed in mice engrafted with PBL from seronegative patients which were infected with B95-8 virus 6 weeks after transfer of the cells. This model is useful for investigating mechanisms of EBV-induced LDP in immunodeficient patients.

Differential expression of CD24-related epitopes in mycosis fungoides/Sézary syndrome: a potential marker for circulating Sézary cells

In the hematopoietic system, the B-cell associated antigen CD24 is expressed at high density on B cells, B-cell precursors, and B-cell malignancies as well as at low density on peripheral blood polymorphonuclear leukocytes. The 42-Kd sialoglycoprotein has not been previously demonstrated to be expressed on T cells, thymocytes, or T-cell malignancies. We identified three patients with mycosis fungoides/Sézary syndrome that showed low density expression of the CD24-related epitope recognized by antibody BA-1 on circulating T cells. All three patients had Sézary cells by morphologic assessment and clonal T-cell populations in the peripheral blood by gene rearrangement studies. In two of these patients, indirect immunofluorescence with a panel of six anti-CD24 monoclonal antibodies demonstrated reactivity for two of six antibodies in one case and only one of six antibodies in the other. The biologic significance of CD24-related epitope expression on circulating T cells in mycosis fungoides/Sézary syndrome is unclear. However, these findings suggest that differential, low density expression of CD24-related epitopes (BA-1+, OKB2-) may be a useful phenotypic marker for identifying circulating Sézary cells.

Characterization of Epstein-Barr virus-induced lymphoproliferation derived from human peripheral blood mononuclear cells transferred to severe combined immunodeficient mice

Mice with severe combined immunodeficiency (SCID) received 6 X 10(7) fresh human peripheral blood mononuclear cells (PBMC) intraperitoneally from Epstein-Barr virus (EBV)-seropositive and -seronegative donors. B95-8 EBV was inoculated intraperitoneally and intravenously to the mice 6 weeks after transfer of seronegative PBMC. Three of four mice transferred with PBMC from two EBV-seropositive donors and two of four mice from two EBV-seronegative donors inoculated with EBV developed fatal EBV-induced lymphoproliferative disease within 6 to 10 weeks. These tumors were oligoclonal or polyclonal by cytoplasmic immunoglobulin expression. Furthermore no consistent clonal chromosomal abnormalities were shown. Cell lines established from these tumors showed low cloning efficiency in soft agarose. In addition, latent membrane protein, B-lymphocyte activation antigen (CD23), and cell-adhesion molecules (ICAM-1, CD18) all were expressed in the EBV-positive infiltrating lymphoproliferative lesions in each mouse. These results suggest that lymphoid tumors are comparable to lymphoblastoid cell lines immortalized by EBV and are not malignant lymphomas such as Burkitt's lymphoma. This model may be useful for investigating mechanisms responsible for the growing numbers of lymphoproliferative diseases that are occurring in patients with inherited or acquired immunodeficiencies.

Tissue factor antigen and activity are not expressed on the surface of intact cells isolated from an acute promyelocytic leukemia patient

Tissue factor activity and antigen were measured in promyelocytes freshly isolated from a patient with acute promyelocytic leukemia (APL), FAB M3. Determination of functional activity revealed that physically disrupted cells expressed considerable tissue factor of which less than two percent was available prior to physical disruption of the cells. No tissue factor antigen was detectable on the cell surface by fluorescence flow cytometry. In contrast, endotoxin-stimulated peripheral blood monocytes and monoblastic cells isolated from a patient with monoblastic leukemia had notable populations of tissue factor-positive cells by flow cytometry, and expressed higher proportions of total tissue factor activity without disruption. While some cell types may express both tissue factor antigen and activity when intact, others, which can be extremely rich in tissue factor, may express neither antigen nor activity without a triggering event such as cell damage.

Immunovirological studies of fatal infectious mononucleosis in a patient with X-linked lymphoproliferative syndrome treated with intravenous immunoglobulin and interferon-alpha

We have studied a 19-year-old male with X-linked lymphoproliferative syndrome (XLP) and infectious mononucleosis (IM) who was treated with high-dose immunoglobulin (500 mg/kg/day) and recombinant interferon (IFN)-alpha (2 x 10(6) IU/m2/day). Fulminant hepatitis was delayed; however, virus-associated hemophagocytic syndrome, cholestatic jaundice, and renal failure occurred terminally. Initially, nonspecific natural killer (NK) cell activity against K562 cells was normal but it gradually decreased. Although reactive T cells were markedly increased in his blood during the acute phase, spontaneous EBV-positive cell lines were easily established. Additionally, his mononuclear cells produced IFN-gamma but not IFN-alpha prior to treatment. Based on results of in vitro studies, we conclude that both IFN-alpha and IFN-gamma production are likely necessary for inhibiting EBV immortalization in vitro. Both IFN-alpha and -gamma were produced in cultures of B95-8 EBV-infected mononuclear cells from EBV-seropositive healthy individuals. These results suggest that defective EBV-specific cytotoxic T cell activity accompanied with defective or discordant IFN-alpha and -gamma production permitted the development of fatal IM in this patient. Combined treatment with immunoglobulin and IFN-alpha appeared to be partially effective during the early stage of this disease.

Molecular Structure of the Rearranged T-Cell Gamma Chain Gene in a Human Leukemia Which Expresses Its Product

The gamma gene product is a component of the second T-cell receptor. We report a new case of acute lymphoblastic leukemia bearing a CD3+ CD4- CD5+ CD7+ CD8- WT31- immunophenpotype that expresses the gamma peptide. Immunoprecipitation studies using an anti Cγ heteroantisera showed two different bands of 40 and 60 Kd. Southern analysis revealed Cγ1 utilization in the productive rearrangement. The demonstration of Vδ-Jδ1 rearrangement in this leukemia suggests that the 60 Kd band could correspond to the product of the delta gene. The utilization of the Jγ1.3 exon in this leukemia suggests that the T lymphocytes that undergo leukemic transformation are derived from a population different from the circulating γ/δ lymphocytes, that preferentially use the Jγ1.2 (JγP) exon.

Cardiolipin liposomes: a novel flow reagent for detection of anticardiolipin antibodies

The association of autoantibodies with specificity for phospholipids and an increased risk for thromboembolic phenomena has received considerable recent clinical attention. These autoantibodies have been reported in patients with defined autoimmune disorders as well as in patients with no other obvious autoimmune disease symptoms other than isolated or recurrent thromboembolic disease. A significant component of this autoimmune response appears to be related to cardiolipin-directed antibodies. Most studies reported to date have used either an enzyme immunoassay or a radioimmunoassay for detection and quantitation of antiphospholipid antibodies. We have developed a novel flow cytometric assay for detection of anticardiolipin antibodies. The assay, by analogy to polystyrene microsphere assay, utilizes cardiolipin liposomes as solid-phase microspheres for antigen presentation. In comparison to enzyme-linked immunosorbent assay, the flow assay shows similar sensitivity by serum titration, has immunoglobulin class specificity, and is semiquantitative as currently designed. The flow assay is relatively easy to perform and should allow detection of other antiphospholipid specificities with tailoring of the phospholipid makeup of the liposomes.

Age-related changes in naive and memory CD4+ T cells in healthy human children

Subsets of CD4+ T cells originally identified functionally as suppressor-inducer and helper-inducer populations have recently been reinterpreted as naive and memory maturational states. The subsets can be identified by the surface expression of CD45R and CDw29, respectively. Using two-color flow cytometric analysis, we measured these CD4+ T cell subsets in two samples of cord blood and in 26 healthy children between the ages of 1 and 19 years. As has been reported by others, we observed that the majority of CD4+ T cells in cord blood consist predominantly of the CD45R+ subset. With aging we could demonstrate a gradual acquisition of CDw29+, CD4+ T cells and a concomitant gradual decrease in the percentage of CD45R+, CD4+ T cells. These age-related changes are consistent with the concept of naive (CD45R+) and memory (CDw29+) subsets. Further, because of the dynamic changes, their utilization as prognostic indicators in immunologic disease states cannot be applied to children in the same manner as adults.

Acute lymphoblastic leukemia of NK-cell lineage: responses to IL-2

Acute lymphoblastic leukemias with phenotypic characteristics of natural killer cell derived lineage are extremely uncommon. We identified an ALL with a phenotype consistent with an NK-cell of origin. The blasts underwent a proliferative response to r-IL2 in culture but showed no spontaneous or r-IL2 or gamma-INF induced cytotoxicity. With r-IL2 stimulation however, the tumor cells demonstrated a dramatic acquisition of low density CD8 surface positivity and a loss of CD11b expression after short term culture. By comparison to ALL of B or T lineage, NK ALL likely represents an early stage of bone marrow derived NK-cell precursor.

The human B cell-associated antigen CD24 is a single chain sialoglycoprotein

The CD24 human B cell-associated antigen was originally characterized in this laboratory with the use of monoclonal antibody BA-1 combined with a standard radioimmuneprecipitation technique, and was reported to be a three chain glycoprotein complex of 45, 55, and 65 kilodaltons. We have compared our standard radioimmuneprecipitation technique (BA-1 ascites followed by rabbit anti-mouse IgM-coated protein A-Sepharose) to BA-1 conjugated directly to CNBr-Sepharose (BA-1-Sepharose) and report striking differences in the electrophoretic profile of CD24 immuneprecipitates. The CD24 immuneprecipitate obtained with BA-1-Sepharose showed a single broad band with a relative mobility of 42 kilodaltons. A series of experiments performed with the two immuneprecipitation techniques, reducing or nonreducing electrophoretic conditions, and addition of preformed mock BA-1 immuneprecipitate to BA-1-Sepharose immuneprecipitates convincingly demonstrated that the previously described 55 and 65 kilodalton components were artifacts caused by co-migration of CD24 with IgG and IgM heavy chains, respectively. Because of the consistent association and co-migration of CD24 with IgG heavy chains, we investigated the possibility that CD24 might be related to the 45 kilodalton Fc-gamma receptor expressed on B cells and eosinophils. We found, however, no evidence for such a relationship by cross adsorption analysis with BA-1-Sepharose and IgG-Sepharose.

The human B cell-associated antigen CD24 is a single chain sialoglycoprotein

The CD24 human B cell-associated antigen was originally characterized in this laboratory with the use of monoclonal antibody BA-1 combined with a standard radioimmuneprecipitation technique, and was reported to be a three chain glycoprotein complex of 45, 55, and 65 kilodaltons. We have compared our standard radioimmuneprecipitation technique (BA-1 ascites followed by rabbit anti-mouse IgM-coated protein A-Sepharose) to BA-1 conjugated directly to CNBr-Sepharose (BA-1-Sepharose) and report striking differences in the electrophoretic profile of CD24 immuneprecipitates. The CD24 immuneprecipitate obtained with BA-1-Sepharose showed a single broad band with a relative mobility of 42 kilodaltons. A series of experiments performed with the two immuneprecipitation techniques, reducing or nonreducing electrophoretic conditions, and addition of preformed mock BA-1 immuneprecipitate to BA-1-Sepharose immuneprecipitates convincingly demonstrated that the previously described 55 and 65 kilodalton components were artifacts caused by co-migration of CD24 with IgG and IgM heavy chains, respectively. Because of the consistent association and co-migration of CD24 with IgG heavy chains, we investigated the possibility that CD24 might be related to the 45 kilodalton Fc-gamma receptor expressed on B cells and eosinophils. We found, however, no evidence for such a relationship by cross adsorption analysis with BA-1-Sepharose and IgG-Sepharose.