Results of R-ESHAP as salvage therapy in refractory/relapsed follicular lymphoma: a real-world experience on behalf of GELCAB group.

There is no standard treatment for relapsed follicular lymphoma (FL). Although platinum-based combinations are one of the most used treatments, few data have been reported in this setting. Our aim was to analyse R-ESHAP efficacy in relapsed FL patients. We retrospectively analysed 80 FL patients treated with R-ESHAP in the first or successive relapses. Responding patients received a stem cell transplantation following R-ESHAP. Seventeen histologically transformed patients were included. Median age was 50 years. At R-ESHAP initiation, 85% of the patients were in an advanced stage, 28% had a bulky disease and 40% had increased LDH. There were no statistically significant differences between POD24 and non-POD24 patients in terms of response to R-ESHAP (ORR 72% vs. 93%, p = 0.109). When analyzing R-ESHAP efficacy according to the response to the immediately previous line, patients achieving CR or PR had better CR rates to R-ESHAP than those who did not respond (CR of 57% vs. 15%, respectively, p = 0.009), as well as differences in OS (7.2 vs. 1.4 years, p < 0.0001) and in PFS (2.1 vs. 0.3 years, p < 0.0001). R-ESHAP is an effective treatment in relapsed FL patients who respond to the previous line and has to be considered as an adequate alternative for some patients.

High resolution melting analysis for the identification of novel mutations in DKC1 and TERT genes in patients with dyskeratosis congenita.

Dyskeratosis congenita (DC) is a rare inherited bone-marrow failure syndrome with high clinical heterogeneity. Cells derived from DC patients present short telomeres at early ages, as a result of mutations in genes encoding components of the telomerase complex (DKC1, TERC, TERT, NHP2 and NOP10), or the shelterin complex (TINF2). However, mutations have been identified only in around 50% of the cases, indicating that other genes could be involved in the development of this disease. Indeed, mutations in TCBA1 or chromosome segment C16orf57 have been described recently. We have used HRM technology to perform genetic analysis in the above mentioned genes, in Spanish patients showing both, some clinical features of DC and short telomeres. The mutations have been identified by PCR amplification of DC genes followed by high resolution melting (HRM) and direct DNA sequencing analysis. We have identified seven new families with DC, three with X-linked DC and four with autosomal dominant DC, in which we have found two novel mutations in DKC1 (p.His68Arg and p.Lys390del) and four novel mutations in TERT gene (p.Pro530Leu, p.Arg698Trp, p.Arg971His and p.Arg698Gln). The results show that the use of HRM analysis enables a rapid and inexpensive identification of mutations in dyskeratosis congenita associated genes.

A real-life overview of a hematopoietic cell transplant program throughout a four-year period, including prospective registry, exclusion causes and final donor selection.

Traceability of patients who are candidates for Hematopoietic cell transplant (HCT) is crucial to ensure HCT program quality. Continuous knowledge of both a detailed registry from a HCT program and final exclusion causes can contribute to promoting a real-life vision and optimizing patient and donor selection. We analyzed epidemiological data reported in a 4 year-monocentric prospective registry, which included all patients presented as candidates for autologous (Auto) and/or allogeneic (Allo) HCT. A total of 543 patients were considered for HCT: 252 (42.4%) for Allo and 291 (57.6%) for Auto. A total of 98 (38.9%) patients were excluded from AlloHCT due to basal disease progression more commonly (18.2%). Seventy-six (30.2%) patients had an HLA identical sibling, whereas 147 (58.3%) patients had only Haplo. UD research was performed in 106 (42%) cases, significantly more often in myeloid than lymphoid malignancies (57% vs 28.7%, p < 0.001) but 61.3% were finally canceled, due to donor or disease causes in 72.4%. With respect to Auto candidates, a total of 60 (20.6%) patients were finally excluded; progression was the most common cause (12%). Currently, Haplo is the most frequent donor type. The high cancellation rate of UD research should be revised to optimize further donor algorithms.

Different methylation signatures at diagnosis in patients with high-risk myelodysplastic syndromes and secondary acute myeloid leukemia predict azacitidine response and longer survival.

BACKGROUND: Epigenetic therapy, using hypomethylating agents (HMA), is known to be effective in the treatment of high-risk myelodysplastic syndromes (MDS) and acute myeloid leukemia (AML) patients who are not suitable for intensive chemotherapy and/or allogeneic stem cell transplantation. However, response rates to HMA are low and there is an unmet need in finding prognostic and predictive biomarkers of treatment response and overall survival. We performed global methylation analysis of 75 patients with high-risk MDS and secondary AML who were included in CETLAM SMD-09 protocol, in which patients received HMA or intensive treatment according to age, comorbidities and cytogenetic. RESULTS: Unsupervised analysis of global methylation pattern at diagnosis did not allow patients to be differentiated according to the cytological subtype, cytogenetic groups, treatment response or patient outcome. However, after a supervised analysis we found a methylation signature defined by 200 probes, which allowed differentiating between patients responding and non-responding to azacitidine (AZA) treatment and a different methylation pattern also defined by 200 probes that allowed to differentiate patients according to their survival. On studying follow-up samples, we confirmed that AZA decreases global DNA methylation, but in our cohort the degree of methylation decrease did not correlate with the type of response. The methylation signature detected at diagnosis was not useful in treated samples to distinguish patients who were going to relapse or progress. CONCLUSIONS: Our findings suggest that in a subset of specific CpGs, altered DNA methylation patterns at diagnosis may be useful as a biomarker for predicting AZA response and survival.

Efficacy of transfusion of platelet concentrates obtained by manual pooling or by semiautomated pooling of buffy-coats: a retrospective analysis of count increment, corrected count increment and transfusion interval.

BACKGROUND AND OBJECTIVE: The preparation of platelet concentrates from pooling buffy-coats can be done manually or semiautomatically with the OrbiSac BC System. The objective of this study was to compare the clinical outcome of platelet transfusions prepared by these two methods in terms of 1-h count increment (1-h CI), 1-h corrected count increment (1-h CCI) and transfusion interval. MATERIALS AND METHODS: Platelet transfusions were identified retrospectively for inclusion in the control group (manual pooling) or the test group (automated pooling). Transfusion outcome variables were 1-h CI, 1-h CCI and transfusion interval. The impact of 16 patient- and platelet concentrate-related variables on transfusion efficacy was investigated by multiple regression analysis. RESULTS: The database analysed consisted of 205 control transfusions given to 36 patients and 219 test transfusions given to 36 patients. Mean platelet content and mean 1-h CI were statistically higher in the test group when compared to the control group (P < 0.05), but mean 1-h CCI and transfusion interval were not. Multiple regression analysis resulted in models explaining 13% of the variance of 1-h CI, 8% of the variance of 1-h CCI and 17% of the variance of transfusion interval (P < 0.05). CONCLUSION: There are no significant differences between the two preparation methods regarding the clinical outcome of platelet transfusions, as the difference in 1-h CI is explained by differences in platelet content.

Intensive chemotherapy (high-dose CHOP/ESHAP regimen) followed by autologous stem-cell transplantation in previously untreated patients with peripheral T-cell lymphoma.

AIM: To analyze toxicity, response and outcome of a phase II trial with intensive chemotherapy plus autologous stem-cell transplantation (ASCT) for young patients with peripheral T-cell lymphoma (PTCL). PATIENTS AND METHODS: Forty-one patients [30 males and 11 females, median age 47 years] consecutively diagnosed with PTCL received three courses of high-dose cyclophosphamide 2000 mg/m(2)/day, adriamycin 90 mg/m(2)/day, vincristine and prednisone alternating with three courses of etoposide, cisplatin, cytarabine and prednisone. Responders were submitted to ASCT. RESULTS: Sixty-eight percent of patients received the planned treatment. After chemotherapy, 20 patients reached complete response (CR), 4 partial response and 17 failed. ASCT was carried out in 17 of 24 candidates due to lack of mobilization (three cases), toxicity (two), early relapse and patient decision (one each). CR rate after treatment was 51%. With a median follow-up of 3.2 years, 5 of 21 CR patients relapsed and 2 died in CR due to secondary neoplasms. Four-year progression-free survival was 30%. Twenty-two patients have died, with a 4-year overall survival of 39%. International Prognostic Index was the main variable predicting survival. No differences were seen among the 24 candidates according to whether or not they underwent ASCT. CONCLUSION: This intensive regimen resulted in moderate CR rate, with manageable toxicity in PTCL. The contribution of ASCT in preventing relapse is debatable. Novel strategies to increase CR warrant investigation.

Prognostic and biological implications of genetic abnormalities in multiple myeloma undergoing autologous stem cell transplantation: t(4;14) is the most relevant adverse prognostic factor, whereas RB deletion as a unique abnormality is not associated with adverse prognosis.

Fluorescence in situ hybridization (FISH) has become a powerful technique for prognostic assessment in multiple myeloma (MM). However, the existence of associations between cytogenetic abnormalities compels us to re-assess the value of each abnormality. A total of 260 patients with MM at the time of diagnosis, enrolled in the GEM-2000 Spanish transplant protocol, have been analyzed by FISH in order to ascertain the independent influence on myeloma prognosis of IGH translocations, as well as RB and P53 deletions. Survival analyses showed that patients with t(4;14), RB or P53 deletions had a significantly shorter survival than patients without these abnormalities. However, patients with RB deletions without other abnormalities in FISH analysis, displayed a similar outcome to those patients without genetic changes by FISH (46 vs 54 months, P=0.3). In the multivariate analysis the presence of t(4;14), RB deletion associated with other abnormalities, age >60 years, high proportion of S-phase cells and advanced stage of the disease according to the International Staging System retained their independent prognostic influence. In summary, RB deletion as a sole abnormality does not lead to a shortening in the survival of MM patients, whereas t(4;14) confers the worst prognosis in MM patients treated with high-dose chemotherapy.

Outcome of patients with acute promyelocytic leukemia failing to front-line treatment with all-trans retinoic acid and anthracycline-based chemotherapy (PETHEMA protocols LPA96 and LPA99): benefit of an early intervention.

To determine prognosis of acute promyelocytic leukemia (APL) failing to front-line therapy with all-trans retinoic acid (ATRA) and anthracyclines, outcome of 52 patients (32 M/20 F; age: 37, 3-72) included in PETHEMA trials LPA96 and LPA99 who presented with either molecular failure (MOLrel, n=16) or hematological relapse (HEMrel, n=36) was analyzed. Salvage therapy consisted of ATRA and high-dose ara-C-based chemotherapy (HDAC) in most cases (83%), followed by stem-cell transplantation (autologous, 18; allogeneic, 10; syngeneic, 1). Fourteen patients with MOLrel (88%) achieved second molecular complete response (molCR), whereas 81% HEMrel patients responded to second-line treatment, with 58% molCR. After median follow-up of 45 months, four MOLrel and 18 HEMrel patients, respectively, experienced a second relapse. Outcome after MOLrel compared favorably to HEMrel, with longer survival (5-year survival: 64+/-14 vs 24+/-8%, P=0.01) and lower relapse risk (5-year relapse risk: 30+/-13 vs 64+/-9%; P=0.044). Additionally, age

Neuropathic pain in cancer patients treated with bortezomib. / Dolor neuropático en pacientes oncológicos en tratamiento con bortezomib.

INTRODUCTION: The neuropathic pain is the most habitual problem in the neuropathy induced by chemotherapy (NIQ) and the one that more interferes in the quality of life of the patients. His precocious detection turns out to be fundamental to reduce or to eliminate the problems that from this one stem. The aims of this study were: 1) determine the incident and NIQ's characteristics and neuropathic pain in patients with mieloma multiple (MM) treated with bortezomib, and 2) to evaluate the impact of the neuropathic pain in the activities of the daily life (AVD). METHOD: All the patients diagnosed of MM candidates for treatment with bortezomib attended in the Hospital Joan XXIII during 2013, took part. The participants were interviewed individually and were reporting on the presence, the characteristics and the impact of the pain, as well as of the adverse effects of the bortezomib. RESULTS: There took part 22 persons, of which NIQ presented the half, being the degree 2 the predominant one. The most habitual location of the neuropathic pain was hands and feet; it was appearing in a spontaneous and progressive way deteriorating in rest and during the night, with predominance of positive symptoms. The impact of the pain was reflected in all the AVD. The principal limitation was the disability to enjoy the life. The peripheral neuropathy occupied the first place in order of subjective importance for the patient followed by the fatigue and the constipation. CONCLUSIONS: A proper assessment and early detection of neuropathic pain is critical to minimizing its impact on the quality of life of patients.

Long-term outcome of older patients with newly diagnosed de novo acute promyelocytic leukemia treated with ATRA plus anthracycline-based therapy.

Treatment outcome in older patients with acute promyelocytic leukemia (APL) is lower compared with younger patients, mainly because of a higher induction death rate and postremission non-relapse mortality (NRM). This prompted us to design a risk- and age-adapted protocol (Programa Español de Tratamientos en Hematología (PETHEMA)/HOVON LPA2005), with dose reduction of consolidation chemotherapy. Patients aged ⩾60 years reported to the PETHEMA registry and were treated with all-trans retinoic acid (ATRA) plus anthracycline-based regimens according to three consecutive PETHEMA trials that were included. We compared the long-term outcomes of the LPA2005 trial with the preceding PETHEMA trials using non-age-adapted schedules (LPA96&LPA99). From 1996 to 2012, 389 older patients were registered, of whom 268 patients (69%) were eligible. Causes of ineligibility were secondary APL (19%), and unfit for chemotherapy (11%). Median age was 67 years, without relevant differences between LPA2005 and LPA96&LPA99 cohorts. Overall, 216 patients (81%) achieved complete remission with no differences between trials. The 5-year NRM, cumulative incidence of relapse, disease-free survival and overall survival in the LPA2005 vs the LPA96&99 were 5 vs 18% (P=0.15), 7 vs 12% (P=0.23), 87 vs 69% (P=0.04) and 74 vs 60% (P=0.06). A less intensive front-line regimen with ATRA and anthracycline monochemotherapy resulted in improved outcomes in older APL patients.

Integrating genomic alterations in diffuse large B-cell lymphoma identifies new relevant pathways and potential therapeutic targets.

Genome studies of diffuse large B-cell lymphoma (DLBCL) have revealed a large number of somatic mutations and structural alterations. However, the clinical significance of these alterations is still not well defined. In this study, we have integrated the analysis of targeted next-generation sequencing of 106 genes and genomic copy number alterations (CNA) in 150 DLBCL. The clinically significant findings were validated in an independent cohort of 111 patients. Germinal center B-cell and activated B-cell DLBCL had a differential profile of mutations, altered pathogenic pathways and CNA. Mutations in genes of the NOTCH pathway and tumor suppressor genes (TP53/CDKN2A), but not individual genes, conferred an unfavorable prognosis, confirmed in the independent validation cohort. A gene expression profiling analysis showed that tumors with NOTCH pathway mutations had a significant modulation of downstream target genes, emphasizing the relevance of this pathway in DLBCL. An in silico drug discovery analysis recognized 69 (46%) cases carrying at least one genomic alteration considered a potential target of drug response according to early clinical trials or preclinical assays in DLBCL or other lymphomas. In conclusion, this study identifies relevant pathways and mutated genes in DLBCL and recognizes potential targets for new intervention strategies.

The expression level of BAALC-associated microRNA miR-3151 is an independent prognostic factor in younger patients with cytogenetic intermediate-risk acute myeloid leukemia.

Acute myeloid leukemia (AML) is a heterogeneous disease whose prognosis is mainly related to the biological risk conferred by cytogenetics and molecular profiling. In elderly patients (⩾60 years) with normal karyotype AML miR-3151 have been identified as a prognostic factor. However, miR-3151 prognostic value has not been examined in younger AML patients. In the present work, we have studied miR-3151 alone and in combination with BAALC, its host gene, in a cohort of 181 younger intermediate-risk AML (IR-AML) patients. Patients with higher expression of miR-3151 had shorter overall survival (P=0.0025), shorter leukemia-free survival (P=0.026) and higher cumulative incidence of relapse (P=0.082). Moreover, in the multivariate analysis miR-3151 emerged as independent prognostic marker in both the overall series and within the unfavorable molecular prognostic category. Interestingly, the combined determination of both miR-3151 and BAALC improved this prognostic stratification, with patients with low levels of both parameters showing a better outcome compared with those patients harboring increased levels of one or both markers (P=0.003). In addition, we studied the microRNA expression profile associated with miR-3151 identifying a six-microRNA signature. In conclusion, the analysis of miR-3151 and BAALC expression may well contribute to an improved prognostic stratification of younger patients with IR-AML.

Cunninghamella bertholletiae infection (mucormycosis) in a patient with acute T-cell lymphoblastic leukemia.

Cunninghamella spp. are unusual opportunistic pathogens that have been identified with increased frequency in immunocompromised patients. Clinical infection by this fungus is almost always devastating and usually fatal. Infections with this group of organisms have been seen most frequently in patients with hematological malignancy. Here we report the case of a patient with acute leukemia who developed multiorganic failure as a consequence of hematological dissemination by Cunninghamella bertholletiae. The case highlights the mortality associated with this fungal infection in immunocompromised patients, confirms the risk factors associated with non-candida fungal infections and shows a clinical presentation mimicking myocardial infarct and cerebrovascular stroke.

Large-cell lymphoma: a study of prognostic factors and assessment of five recently proposed predictive systems.

The main initial and evolutive variables of 133 patients with large-cell lymphoma treated with adriamycin-containing regimens were evaluated for prognostic significance. At the time of analysis, 66 patients had died with the median survival of the series being 48.9 months. Variables associated with poor prognosis in the univariate study were: lymphoma of immunoblastic subtype, advanced Ann Arbor stage, presence of B-symptoms, poor performance status, bulky disease (> or = 10 cm), involvement of two or more extranodal sites, bone marrow infiltration, and high serum LDH levels. In the multivariate analysis, Ann Arbor stage (p < 0.001), bulky disease (p = 0.004), performance status (p = 0.018), and histologic subtype (p = 0.021) retained their prognostic value. After excluding those patients with localized disease (stage I), the Ann Arbor staging system lost prognostic significance in favor of bone marrow infiltration (p = 0.009) and serum LDH (p < 0.001). However, when response to treatment was included in the regression model, it proved to be the most important prognostic factor (p < 0.001), followed by serum LDH (p = 0.004). On the other hand, when the analysis was restricted to complete responders, serum LDH at diagnosis was the only parameter useful to predict survival (p = 0.008). Finally, five recently proposed prognostic classifications were useful to separate different risk-groups of patients when applied to the series.

Low-grade lymphoma: clinical and prognostic studies in a series of 143 patients from a single institution.

Clinical and prognostic studies were carried out in a series of 143 patients with low-grade (small-lymphocytic, follicular small cleaved cell, follicular mixed small- and large-cell) lymphoma. After treatment with alkylating agents (21.5% cases), combination chemotherapy (73.3%) or other therapies (5.2%), complete response (CR) was obtained in 40.7% of cases and partial response (PR) in 43.7%. The stage of the disease was the most important factor for response. With a median follow-up of 6.5 years, 48.0% (95% Cl: 37.5-58.5) of patients were alive 10 years after diagnosis. Among the initial parameters, advanced stage. B-symptoms, poor performance status, nodal involvement > 3 sites, extranodal involvement > or = 2 sites, WBC count > or = 10 x 10(9)/L, leukemic expression, high serum LDH levels, and bone marrow infiltration were all related to survival; treatment modality, however, had no influence on survival. In the multivariate analysis, stage (p = 0.008) and age (p = 0.053) were the most important prognostic factors. When considering response to therapy, both CR (p < 0.001) and PR (p = 0.003) emerged as the most important predictive variables, with only the absence of B-symptoms retaining its prognostic significance (p = 0.014) among the other parameters. In addition, in CR patients the duration of the response (< or = 1 year vs. > 1 year) was the most significant parameter for survival (p < 0.001). Finally, the initial stage (p = 0.011) and the histologic subtype (those patients with follicular mixed lymphoma relapsing less frequently than the others) (p = 0.052) were the only significant factors for relapse.

Autoanti-D in a patient after cladribine treatment for lymphoplasmocytic lymphoma.

We report the case of a 62-year-old woman who developed an autoanti-D after cladribine treatment. In May 2000, the patient underwent splenectomy for a stage IV-B lymphoplasmocytic lymphoma. She was transfused with ABO- and Rh(D)-matched blood. A month later, she received chemotherapy with cladribine. In February 2001, blood grouping showed her to be AB, D+ and the direct antiglobulin test was positive for IgG. An autoanti-D was identified in the eluate. Genotypic analysis confirmed the Rh phenotype of the patient as ccDEe. No hemolysis was evident, as judged by the absence of anemia, a bilirubin of 15.7 micromol/L, and lactic dehydrogenase of 412 IU/L. When an anti-D is identified in a D+ blood recipient, a passive transfer of anti-D, and an alloimmunization in a recipient with a weak D phenotype, should be ruled out. Finally, as in our case, an autoantibody is an additional possibility.

The direct antiglobulin test in a hospital setting.

To evaluate the current use of the DAT in our hospital,we reviewed the charts of all patients who had a DAT performed in our laboratory. The collected data included DAT results and a previously completed laboratory evaluation of suspected hemolytic anemia. Four hundred sixty-three DATs were performed in our laboratory from April 1999 to October 2001. The DAT was negative in 434 (93.7%) cases and positive in 29 (6.3%) cases. A complete laboratory evaluation of suspected hemolytic anemia was seen in 179 (38.7%) cases. The incidence of a positive DAT was higher in the group of patients with > 2 signs of hemolysis (4/34 cases; 11.8%) than in the group of patients with

[Alpha interferon treatment of idiopathic myelofibrosis]. / Tratamiento con interferón alfa de la mielofibrosis idiopática.

Idiopathic myelofibrosis is a chronic myeloproliferative syndrome for which there is no effective treatment. The good results obtained with interferon in other chronic myeloproliferative syndromes have led their being tested in idiopathic myelofibrosis, but to date the experience is scarce. Four patients out of a total of 12 diagnosed with idiopathic myelofibrosis over a period of 3 years were selected for interferon treatment. Patients with low leukocyte or platelet counts or with contraindication for administration of the drug were excluded. Alpha-2b interferon was administered at an initial dose of 3 MU/day which was increased at 4-6 weeks to 5 MU/day in cases of insufficient response and if tolerance so permitted. In patients in whom favorable response was observed a maintenance schedule was initiated with low doses of interferon. Treatment was discontinued in two patients due to bad tolerance at 6 and 8 weeks of initiation of treatment with no response having been observed until that time. In the other patients favorable response was reported to interferon after 5 months of treatment with disappearance of the symptomatology, normalization of the hemo-peripheral values and a marked reduction of splenomegaly. This responses was accompanied by a decrease in bone marrow fibrosis in one case and total disappearance of the same in the other patient. Alpha-2b interferon constitutes an effective therapy for a selected number of patients with idiopathic myelofibrosis. Greater experience would allow the identification of the subgroup of patients who may benefit from this type of treatment.

[Paroxysmal cold hemoglobinuria: only in the textbooks?]. / Hemoglobinuria paroxística a frigore: sólo en los libros de texto?

Although it was common in the preantibiotic era, paroxysmal cold hemoglobinuria (PCH) is now an exceptional condition. A 34-year-old female with anemia and episodic hemoglobinuria provoked by cold is reported. The laboratory studies suggested intravascular hemolytic anemia, and the Donath-Landsteiner test showed a biphasic IgG hemolysin with anti-P specificity. This finding and the evidence of latent syphilis were diagnostic of PCH. Penicillin therapy suppressed the hemolytic episodes, although the Donath-Landsteiner test is still positive. It is concluded that PCH is still an exisiting disease which should be considered in the differential diagnosis of episodic hemoglobinuria.

[T lymphoid blast crisis of Philadelphia chromosome-positive chronic myeloid leukemia: analysis of 3 cases]. / Crisis blástica linfoide T de la leucemia mieloide crónica cromosoma Filadelfia positiva: análisis de tres casos.

BACKGROUND: To investigate the frequency of the T lymphoid phenotype in the blast crisis of chronic myelocytic leukemia (CML) with positive Philadelphia chromosome (Ph) and to evaluate the major clinical and hematologic features of the patients with this phenotype. METHODS: The presence of the TdT enzyme was assessed and specific monoclonal antibodies to the different hemopoietic lines were used to evaluate blast cells in 38 patients with blast crisis during Ph-positive CML. RESULTS: T lymphoid phenotype was found in three of the 38 patients, corresponding in all cases to immature T cells. In one patient, the blast crisis was the presenting feature of CML and in two the localization of the blast crisis was lymphadenopathic. In the two patients who could be followed up a favorable response to chemotherapy regimens including vincristine and prednisone was observed. CONCLUSIONS: Although uncommon, T lymphoid blast crisis in CML should no longer be considered exceptional. This phenotypic finding suggests that, at least in some cases, CML originates in a pluripotential stem cell common to all hemopoietic cells, including T lymphocytes.