pentostatin and Acute-Disease

Graft-versus-host disease is one of the commonest complications of allogeneic bone marrow or peripheral blood stem cell transplantation. This review will cover advances in the pathophysiology of graft-versus-host disease and new agents under investigation for the treatment of this disorder. Patients developing graft-versus-host disease who fail to respond to steroids have a poor prognosis. In this group of people, morbidity and mortality are very high.. Novel agents are currently under investigation for the treatment of such devastating disorders. Pentostatin, denileukin diftitox, mycophenolate mofetil, extracorporeal photopheresis, and several monoclonal antibodies have been used, some of them with encouraging results.. As supportive care improves and new agents are added to the armamentarium against steroid-refractory acute graft-versus-host disease, the prognosis of this entity may start to change. Patients with this complication after transplantation should be enrolled, whenever possible, in clinical trials to find effective therapies.

Topics: Acute Disease; Animals; Antibodies, Monoclonal; Bone Marrow Transplantation; Diphtheria Toxin; Drug Resistance; Graft vs Host Disease; Hematopoietic Stem Cell Transplantation; Humans; Interleukin-2; Mycophenolic Acid; Pentostatin; Photopheresis; Recombinant Fusion Proteins; Steroids

The purine nucleoside analogues (PNA), fludarabine (FA), cladribine (2-chlorodeoxyadenosine, 2-CdA) and 2'-deoxycoformycin (DCF), represent a novel group of cytotoxic agents with high activity in low-grade lymphoid malignancies. However, several investigations have revealed that these agents are active also in acute myeloid leukemia (AML) and chronic myelogenous leukemia (CML). Synergistic interaction between FA or 2-CdA with cytarabine (Ara-C) have been demonstrated in both preclinical and clinical studies. PNA enhance the cell concentration of Ara-CTP, which is active metabolite of Ara-C. It is likely that the addition of granulocyte colony stimulating factor (G-CSF) may further improve the effects of FA (FLAG) or 2-CdA (CLAG). The addition of anthracyclines to induction therapy does not appear to result in a substantial advantage in terms of CR achievement and duration. An alternative approach to increase FLAG activity might be the addition of investigational drugs with novel mechanism of action, such as topoiromerase I inhibitors. The addition of anthracyclines to induction therapy does not appear to result in a substantial advantage in terms of CR achievement and duration. Clinical studies have confirmed the efficacy of PNA alone or in combination protocols in the treatment of AML. These regimens seem to produce superior results with acceptable toxicities in previously treated and relapsed, poor risk AML. However, early relapses remain a significant problem in a majority of refractory or relapsed patients in CR after treatment with PNA based regimens. To prolong remission duration or even cure AML, auto--or allo stem cell transplantation should be considered. However, FAMP or 2-CdA containing regimens may impair mobilization and collection of stem cells from peripheral blood for autotransplantation. Few studies have analyzed the role of PNA in CML. 2-CdA, FAMP and DCF can induce hematologic response in chronic phase of CML but cytogenetic responses have not been observed. Preliminary results suggest, that PNA used alone or in combination may be used as palliation in blast phase of the disease. However, currently, the role of these agents in CML is insignificant because of the high activity of Glivec in this disease. Finally, PNA, especially FA play an important role in non-myeloablative conditioning regimens for allogenic stem cell transplantation in high-risk patients, possibly also with myeloid malignancies.

Topics: Acute Disease; Adolescent; Adult; Aged; Antibiotics, Antineoplastic; Antimetabolites, Antineoplastic; Antineoplastic Combined Chemotherapy Protocols; Child; Child, Preschool; Cladribine; Clinical Trials as Topic; Cytarabine; Drug Synergism; Female; Granulocyte Colony-Stimulating Factor; Hematopoietic Stem Cell Mobilization; Humans; Infant; Leukemia, Myelogenous, Chronic, BCR-ABL Positive; Leukemia, Myeloid; Male; Middle Aged; Pentostatin; Peripheral Blood Stem Cell Transplantation; Remission Induction; Salvage Therapy; Transplantation Conditioning; Transplantation, Autologous; Transplantation, Homologous; Treatment Outcome; Vidarabine

Purine analogs are effective in the treatment of several chronic lymphoproliferative disorders (CLPD) including hairy cell leukemia (HCL). To date, little evidence exists that these drugs are oncogenic. We report a case of HCL in a 66-year-old male treated with 2-deoxycoformycin. Just over 1 year following completion of his treatment, falling platelet and white cell counts were associated with the development of dysplastic features in his bone marrow and a rising blast cell count, culminating in the development of acute myeloid leukemia (AML). To the best of our knowledge only two previous cases of AML have been linked to treatment of HCL with purine analogs, both with 2-chlorodeoxyadenosine. We emphasize the need for long term follow up of patients treated with purine analogs and suggest that even those who are apparently cured be monitored periodically.

Topics: Acute Disease; Aged; Antimetabolites, Antineoplastic; Fatal Outcome; Humans; Leukemia, Hairy Cell; Leukemia, Myeloid; Leukocyte Count; Male; Myelodysplastic Syndromes; Neoplasms, Second Primary; Pentostatin; Platelet Count

Bone marrow transplantation has become the modality of choice for a number of malignant conditions. One of the primary causes of morbidity and mortality following bone marrow transplantation is graft-versus-host disease (GVHD). Moderate to severe acute GVHD affects 9% to 35% of patients undergoing standard allogeneic bone marrow transplantation. The incidence of chronic GVHD is approximately 40% to 50%. In our experience at Johns Hopkins Oncology Center, patients with stages 2, 3, and 4 acute GVHD had median survivals of only 5.4, 3.6, and 2.5 months, respectively, despite treatment. Patients with chronic GVHD do not fare much better. Their overall 10-year mortality rate remains high at 42%. Significant failure rates and toxicities have been associated with all available therapeutic options for GVHD. Pentostatin (Nipent; SuperGen, San Ramon, CA) is currently used to treat a variety of hematologic malignancies. In addition to its antineoplastic effects, considerable immunosuppressive properties have been reported. Pentostatin affects the immune system by decreasing lymphocyte number and function. Its immunosuppressive effect has promise for the treatment of GVHD and warrants further study.

Topics: Acute Disease; Bone Marrow Transplantation; Chronic Disease; Graft vs Host Disease; Humans; Immunosuppressive Agents; Incidence; Lymphocytes; Pentostatin; Survival Rate; Transplantation, Homologous; Treatment Outcome

One limitation of reduced-intensity preparative regimens is potential for graft failure. We have developed a regimen that targets CD4(+) lymphodepletion to ensure early and durable engraftment. The primary endpoint was achievement of ≥50% CD3(+) donor chimerism by day +28. Forty-two patients (median age, 53 years; range, 29 to 73 years) received pentostatin 4 mg/m(2) i.v. on days -28, -21, and -14 when the CD4(+) cell count was >100 cells/μL and on days -4 and -3 regardless of CD4(+) level. Rituximab 375 mg/m(2) was administered to patients with CD20(+) malignancies on days -21, -14, -7, +1, and +8. Busulfan 200 mg/m(2) i.v. was administered on days -4 and -2 at a dose to target a cumulative AUC dose of 16,000 (±10%) μmol·min/L. Graft-versus-host disease (GVHD) prophylaxis consisted of tacrolimus plus methotrexate in 86% of patients. Donors were matched-related (47%), matched unrelated (43%), or mismatched unrelated (10%). Chronic lymphocytic leukemia (45%) and follicular non-Hodgkin lymphoma (14%) were the most common diagnoses. Disease status at initiation of the preparative regimen was complete remission in 22%, partial response in 55%, and stable/progression in 24%. The median percent CD4(+) cell count decrease from baseline (day -28) was 52% to day -21, 66% to day -14, 62% to day -7, and 91% to day 0. At day +28, all 42 patients (100%) had ≥50% CD3(+) donor chimerism. No patient experienced graft failure. Overall response rate was 82% (complete remisson, 67%). The day +100 cumulative incidence of grade II-IV acute GVHD was 59% (grade III-IV acute GVHD, 19%), and the 2 year cumulative incidence of chronic GVHD was 69% (moderate/severe, 58%). Nonrelapse mortality was 2% at day +100 and 17% at 2 years. Two-year PFS was 55%, and OS was 68%. This regimen ensures durable engraftment, is effective against persistent disease, and results in relatively low mortality from causes other than relapse.

Topics: Acute Disease; Adult; Aged; Antineoplastic Agents; Busulfan; CD4 Lymphocyte Count; CD4-Positive T-Lymphocytes; Chronic Disease; Female; Graft vs Host Disease; Hematologic Neoplasms; Hematopoietic Stem Cell Transplantation; Humans; Lymphocyte Depletion; Male; Middle Aged; Molecular Targeted Therapy; Pentostatin; Survival Analysis; Transplantation Conditioning; Transplantation, Homologous

Although significant strides have been made in understanding the biology of graft-versus-host disease (GVHD) and its prevention over the last 4 decades, little is known about the different populations of lymphocytes and the changes in response to treatment for this condition. BMT-CTN 0302 was a randomized phase II clinical trial in the Blood and Marrow Transplant Clinical Trials Network that assessed the efficacy of combination therapy with steroids plus pentostatin, mycophenolate mofetil, etanercept, or denileukin diftitox in patients with acute GVHD. Patients enrolled in the study underwent blood analysis by flow cytometry on days 0, 14, and 28 of therapy to enumerate the number of total lymphocytes, T cells, B cells, and lymphocytes expressing activation markers. Baseline total lymphocyte counts and subpopulations were similar in the 4 treatment arms. Responding patients had a smaller decrease in total CD45(+) cell count (P = .005) compared with nonresponding patients at day 28. On univariate analysis, those who developed chronic GVHD had significantly higher CD8(+) cell counts at day 14 compared with those without it (P = .005). There was no significant association between baseline lymphocyte count and survival. On univariate analysis, among the patients with higher lymphocyte counts at days 14 and 28, there was a trend toward better survival at day 180, although this trend did not reach the predetermined threshold for significance. We found no significant differences in lymphocyte total or subpopulation counts among the 4 treatment arms, and no notable influence on outcomes.

Topics: Acute Disease; Adult; Antigens, CD; Antineoplastic Agents; B-Lymphocyte Subsets; Bone Marrow Transplantation; Diphtheria Toxin; Etanercept; Female; Graft vs Host Disease; Humans; Immunoglobulin G; Immunophenotyping; Immunosuppressive Agents; Interleukin-2; Lymphocyte Count; Male; Middle Aged; Mycophenolic Acid; Pentostatin; Receptors, Tumor Necrosis Factor; Recombinant Fusion Proteins; Survival Analysis; T-Lymphocyte Subsets; Transplantation, Homologous

Acute graft-versus-host disease (aGVHD) is the primary limitation of allogeneic hematopoietic cell transplantation. Corticosteroids remain the standard initial therapy, yet only 25% to 41% of patients completely respond. This randomized, 4-arm, phase 2 trial was designed to identify the most promising agent(s) for initial therapy for aGVHD. Patients were randomized to receive methylprednisolone 2 mg/kg per day plus etanercept, mycophenolate mofetil (MMF), denileukin diftitox (denileukin), or pentostatin. Patients (n = 180) were randomized; their median age was 50 years (range, 7.5-70 years). Myeloablative conditioning represented 66% of transplants. Grafts were peripheral blood (61%), bone marrow (25%), or umbilical cord blood (14%); 53% were from unrelated donors. Patients who received MMF for prophylaxis (24%) were randomized to a non-MMF arm. At randomization, aGVHD was grade I to II (68%), III to IV (32%), and (53%) had visceral organ involvement. Day 28 complete response rates were etanercept 26%, MMF 60%, denileukin 53%, and pentostatin 38%. Corresponding 9-month overall survival was 47%, 64%, 49%, and 47%, respectively. Cumulative incidences of severe infections were as follows: etanercept 48%, MMF 44%, denileukin 62%, and pentostatin 57%. Efficacy and toxicity data suggest the use of MMF plus corticosteroids is the most promising regimen to compare against corticosteroids alone in a definitive phase 3 trial. This study is registered at http://www.clinicaltrials.gov as NCT00224874.

Topics: Acute Disease; Adolescent; Adrenal Cortex Hormones; Adult; Aged; Anti-Inflammatory Agents, Non-Steroidal; Antineoplastic Agents; Child; Diphtheria Toxin; Drug Therapy, Combination; Etanercept; Graft vs Host Disease; Hematopoietic Stem Cell Transplantation; Humans; Immunoglobulin G; Infections; Interleukin-2; Methylprednisolone; Middle Aged; Mycophenolic Acid; Pentostatin; Receptors, Tumor Necrosis Factor; Recombinant Fusion Proteins; Survival Rate; Treatment Outcome

Acute graft-versus-host disease (aGVHD) is a major complication of allogeneic bone marrow transplantation. In steroid-refractory aGVHD, mortality is very high. Pentostatin, a potent inhibitor of adenosine deaminase, induces lymphocyte apoptosis and may be useful in the treatment of this condition.. We have conducted a phase I dose escalation study of pentostatin in patients with steroid-refractory aGVHD. Twenty-three patients were enrolled. Starting dose was 1 mg/m2/d by intravenous injection for 3 days.. The maximum tolerated dose was found to be 1.5 mg/m2/d. Late infections at the 2-mg/m2/d dose level were believed to be dose limiting toxicities. Lymphopenia was universal, but the neutrophil count was generally not affected. Fevers associated with neutropenia were not observed. Otherwise, the drug was well tolerated, with only modest elevations of liver function tests and thrombocytopenia, each being observed in a single patient. Twenty-two patients were assessable for response, including 14 complete responses (63%) and three partial responses (13%). Median survival after therapy for the group was 85 days (range, 5 to 1,258 days).. The suggested intravenous dose for a phase II study will be 1.5 mg/m2/d for 3 days. Pentostatin has activity in patients with steroid-refractory aGVHD that is worth exploring in future trials.

Topics: Acute Disease; Adolescent; Adult; Apoptosis; Bone Marrow Transplantation; Child; Child, Preschool; Dose-Response Relationship, Drug; Female; Graft vs Host Disease; Hematologic Neoplasms; History, 16th Century; Humans; Immunosuppressive Agents; Infant; Infusions, Intravenous; Lymphocytes; Male; Maximum Tolerated Dose; Middle Aged; Pentostatin; Transplantation, Homologous; Treatment Outcome

We report outcomes of 60 patients with steroid-refractory (SR)-aGVHD treated with pentostatin. Almost half (47%) of patients had grade 4 GVHD-22% had stage 3-4 liver GVHD and 51% had stage 3-4 lower gastrointestinal tract (LGI) GVHD. Patients received a median of 3 courses (range, 1-9) of pentostatin. Day 28 overall response rate (ORR) was 33% (n = 20) (complete response 18% (n = 11), partial response 15% (n = 9)). Non-relapse mortality was 72% (95% confidence interval (CI) 61-84%) and overall survival (OS) was 21% (95% CI 12-32%) at 18 months. On univariate analysis, age >60 years (HR 1.9, 95% CI 1.01-3.7, p = 0.045) and presence of liver GVHD (HR 1.9, 95% CI 1.9, 95% CI 1.5-3.3, p = 0.03) were significant predictors of poor OS while patients with LGI GVHD had superior OS than those without (HR 0.4, 95% CI 0.2-0.8, p = 0.01). On stratified analysis, patients <60 years with isolated LGI GVHD had the best outcomes with an ORR of 48% and OS of 42% at 18 months. Among older patients, OS was 14% in those with isolated LGI aGVHD and 0% in others. Pentostatin remains a viable treatment option for SR-aGVHD, especially in patients 60 years or younger with isolated LGI involvement.

Topics: Acute Disease; Adolescent; Adult; Age Factors; Aged; Child; Child, Preschool; Female; Gastrointestinal Diseases; Graft vs Host Disease; Humans; Liver Diseases; Male; Middle Aged; Patient Selection; Pentostatin; Prognosis; Risk Factors; Salvage Therapy; Steroids; Survival Analysis; Young Adult

Topics: Acute Disease; Bone Marrow Transplantation; Boronic Acids; Bortezomib; Chronic Disease; Clinical Trials as Topic; Cyclohexanes; Cyclophosphamide; Cyclosporine; Evidence-Based Medicine; Graft vs Host Disease; Hematopoietic Stem Cell Transplantation; Humans; Hydroxamic Acids; Immunosuppressive Agents; Maraviroc; Methotrexate; Pentostatin; Peripheral Blood Stem Cell Transplantation; Pyrazines; Quality of Life; Tacrolimus; Triazoles; Vorinostat

Topics: Acute Disease; Adenosine Deaminase Inhibitors; Adult; Female; Graft vs Host Disease; Hematologic Neoplasms; Humans; Immunosuppressive Agents; Kaplan-Meier Estimate; Male; Middle Aged; Pentostatin; Peripheral Blood Stem Cell Transplantation; Retrospective Studies; Treatment Outcome; Young Adult

The differentiation-inducing effect of clinically applicable analogs of deoxyadenosine on myelomonocytic leukemia cells was examined. Monocytoid leukemia cells were more sensitive to the analogs than were erythroid or myeloid leukemia cells based on the inhibition of cell growth and induction of cell differentiation. Monocytoid leukemia cells were highly sensitive to combined treatment with 2'-deoxycoformycin (dCF) and 9-beta-D-arabinofuranosyladenine (Ara A) for inducing cell differentiation. Ara A induced the differentiation of monocytoid leukemia U937 and THP-1 cells at concentrations which were 1/1000-10000 of that at which it induced the differentiation of other cell lines in the presence of dCF. In combination with a low concentration of 1alpha,25-dihydroxyvitamin D3 (VD3), the induction of the monocytic differentiation was greater in monoblastic U937 cells. Adenosine deaminase-resistant analogs such as fludarabine (FLU) and cladribine (CdA) also induced the differentiation of human myelomonocytic leukemia cells, and these analogs synergistically enhanced the differentiation induced by all-trans retinoic acid (ATRA) or VD3. CdA was the most potent analog for inducing the differentiation of myeloid leukemia NB4 and HL-60 cells in the presence or absence of ATRA. These findings indicate that dCF + Ara A and CdA may be effective for the therapy of acute monocytoid and myeloid leukemia, respectively.

Topics: Acute Disease; Adenosine Deaminase Inhibitors; Antimetabolites, Antineoplastic; Calcitriol; Cell Differentiation; Cladribine; Deoxyadenosines; Dose-Response Relationship, Drug; Drug Synergism; Enzyme Inhibitors; HL-60 Cells; Humans; K562 Cells; Leukemia, Myeloid; Monocytes; Neoplasm Proteins; Neoplastic Stem Cells; Pentostatin; Tretinoin; Tumor Cells, Cultured; U937 Cells; Vidarabine

Both established cell lines and human leukemic cells in circulating blood which were incubated in vitro with 2'-deoxyadenosine (AdR) plus adenosine deaminase inhibitor, 2'-deoxycoformycin (dCF), showed different metabolic responses depending upon the histologic and immunologic types of leukemia. The leukemic T-cell lines in tissue culture were 200-fold more sensitive than B-cell lines to the toxic effect of deoxyadenosine. The increased sensitivity of T-cell lines to AdR plus dCF was associated with the accumulation of deoxyadenosine triphosphate (dATP) in the cells. In established cell lines, an inverse correlation was observed between ED 50 of AdR plus dCF and the relative increase of dATP levels in the cells after the incubation of the cells with AdR plus dCF. In circulating leukemic cells that had been incubated with AdR and dCF, dATP arose in all groups but the correlation was not found between the sensitivity of AdR and the relative dATP accumulation. The failure to find the correlation in patients's leukemic cells may be attributed to the heterogeneity of the response of the blasts to AdR and dCF.

Topics: Acute Disease; B-Lymphocytes; Cell Line; Cells, Cultured; Coformycin; Deoxyadenine Nucleotides; Deoxyadenosines; Growth Inhibitors; Humans; Leukemia; Leukemia, Experimental; Leukemia, Myeloid; Pentostatin; Ribonucleosides; T-Lymphocytes; Thymidine

Selective failure of lymphoid development occurs in genetic deficiency of adenosine deaminase (ADA). We examined the in vivo effects of a potent inhibitor of ADA, 2'-deoxycoformycin, which was used to treat a patient with refractory acute leukemia. Unexpectedly, within 7 days of starting treatment, the leukemic phenotype underwent complete conversion from T lymphoblastic to promyelocytic, with kinetics that suggested a precursor-product relationship between the two cell populations. Pretreatment T lymphoblasts and posttreatment promyelocytes had the same abnormal karyotype. Upon culture in vitro, the former transformed spontaneously over several weeks into mature myeloid cells. We conclude that the leukemia arose from a multipotent stem cell capable of both lymphoid and myeloid differentiation. Effects of ADA inhibition on leukemia cells during treatment included expansion of the deoxyadenosine nucleotide pool and accumulation of S-adenosylhomocysteine, a potent inhibitor of S-adenosylmethionine-dependent methylation. The influence of these changes on the leukemic phenotype is discussed in terms of (i) selective cytotoxicity to T lymphoblasts, which accumulated deoxyadenosine nucleotides more efficiently than did the patient's promyelocytes during in vitro incubation with deoxycoformycin plus deoxyadenosine, and (ii) induction of an altered program of differentiation.

Topics: Acute Disease; Adenosine Deaminase Inhibitors; Adolescent; Antibodies, Monoclonal; Antigens, Surface; Bone Marrow; Coformycin; Humans; Karyotyping; Leukemia; Leukemia, Myeloid; Male; Nucleoside Deaminases; Pentostatin; Phenotype; Ribonucleosides; T-Lymphocytes

A patient with refractory T-cell acute lymphoblastic leukemia was treated with eight courses of the adenosine deaminase inhibitor, 2'-deoxycoformycin (dCF), over a 5-month period. After developing resistance to dCF, he responded to treatment with the combination of dCF and 9-beta-D-arabinofuranosyladenine (ara-A). We monitored the levels in plasma and urine of adenosine, 2'-deoxyadenosine, and ara-A as well as the accumulation of their nucleotide derivatives in erythrocytes and circulating lymphoblasts. We also monitored the activities of adenosine deaminase and S-adenosylhomocysteine (AdoHcy) hydrolase and the concentrations of AdoHcy and S-adenosylmethionine in lymphoblasts. Production of 2'-deoxyadenosine was related to both the duration of dCF infusion and the magnitude of cytolysis that occurred during treatment: much more 2'-deoxyadenosine was produced by dCF infusion when disease was active than by the same infusion given during remission. Resistance to dCF was associated with a decrease of greater than 90% in the amount of deoxyadenosine 5'-triphosphate accumulated by circulating lymphoblasts. Infusion of dCF resulted in increases of up to 20-fold in the concentration of AdoHcy in circulating lymphoblasts, causing a decrease in the S-adenosylmethionine:AdoHcy ratio (the "methylation index") from a pretreatment value of greater than 40:1 to less than 4:1. This ratio decreased to 2.5:1 during combined treatment with dCF and ara-A, which caused nearly complete inactivation of lymphoblast AdoHcy hydrolase. Decline in the methylation index was accompanied by inhibition of the methylation of newly synthesized lymphoblast RNA. Impaired ability to catabolize AdoHcy may have contributed to the cytolytic responses to dCF and ara-A, as well as to hepatic and central nervous system toxicity associated with their combined use.

Topics: Acute Disease; Adenosine; Adult; Coformycin; Deoxyadenosines; Drug Resistance; Drug Therapy, Combination; Erythrocytes; Homocysteine; Humans; Leukemia, Lymphoid; Lymphocytes; Male; Pentostatin; Ribonucleosides; S-Adenosylhomocysteine; Time Factors; Vidarabine

Topics: Acute Disease; Antineoplastic Agents; Child; Coformycin; Humans; Leukemia, Lymphoid; Male; Methylprednisolone; Pentostatin; Positive-Pressure Respiration; Respiratory Insufficiency; Ribonucleosides

Seventeen patients with acute leukaemia refractory to conventional chemotherapeutic agents were treated with the adenosine deaminase inhibitor, 2'-deoxycoformycin (dCF). Of the twelve patients with acute lymphoblastic leukaemia of the thymic phenotype (Thy-ALL), seven went into complete remission after one or two courses of therapy. Two other (Thy-ALL) patients showed good partial response, and three were resistant to dCF. The five patients with acute leukaemia of other phenotypes had progression of disease despite treatment with dCF. Response to dCF can be predicted from the pattern of change in cellular nucleotide levels in blood and/or bone marrow blasts which have been treated in vitro with dCF and deoxyadenosine. The main adverse effects of dCF therapy were renal and liver dysfunction, conjunctivitis, and haemolysis.

Topics: Acute Disease; Adenosine Deaminase; Adolescent; Adult; Child; Child, Preschool; Coformycin; Conjunctivitis; Female; Hemolysis; Humans; Infant; Kidney; Leukemia; Leukemia, Lymphoid; Liver; Male; Pentostatin; Phenotype; Ribonucleosides; T-Lymphocytes