Efficacy of immune checkpoint inhibitors for the treatment of advanced melanoma in patients with concomitant chronic lymphocytic leukemia.

BACKGROUND: Immune checkpoint inhibitors (ICIs) have revolutionized the management of advanced melanoma (AM). However, data on ICI effectiveness have largely been restricted to clinical trials, thereby excluding patients with co-existing malignancies. Chronic lymphocytic leukemia (CLL) is the most prevalent adult leukemia and is associated with increased risk of melanoma. CLL alters systemic immunity and can induce T-cell exhaustion, which may limit the efficacy of ICIs in patients with CLL. We, therefore, sought to examine the efficacy of ICI in patients with these co-occurring diagnoses. PATIENTS AND METHODS: In this international multicenter study, a retrospective review of clinical databases identified patients with concomitant diagnoses of CLL and AM treated with ICI (US-MD Anderson Cancer Center, N = 24; US-Mayo Clinic, N = 15; AUS, N = 19). Objective response rates (ORRs), assessed by RECIST v1.1, and survival outcomes [overall survival (OS) and progression-free survival (PFS)] among patients with CLL and AM were assessed. Clinical factors associated with improved ORR and survival were explored. Additionally, ORR and survival outcomes were compared between the Australian CLL/AM cohort and a control cohort of 148 Australian patients with AM alone. RESULTS: Between 1997 and 2020, 58 patients with concomitant CLL and AM were treated with ICI. ORRs were comparable between AUS-CLL/AM and AM control cohorts (53% versus 48%, P = 0.81). PFS and OS from ICI initiation were also comparable between cohorts. Among CLL/AM patients, a majority were untreated for their CLL (64%) at the time of ICI. Patients with prior history of chemoimmunotherapy treatment for CLL (19%) had significantly reduced ORRs, PFS, and OS. CONCLUSIONS: Our case series of patients with concomitant CLL and melanoma demonstrate frequent, durable clinical responses to ICI. However, those with prior chemoimmunotherapy treatment for CLL had significantly worse outcomes. We found that CLL disease course is largely unchanged by treatment with ICI.

Ibrutinib modulates the immunosuppressive CLL microenvironment through STAT3-mediated suppression of regulatory B-cell function and inhibition of the PD-1/PD-L1 pathway.

Ibrutinib, a covalent inhibitor of Bruton Tyrosine Kinase (BTK), is approved for treatment of patients with relapsed/refractory or treatment-naïve chronic lymphocytic leukemia (CLL). Besides directly inhibiting BTK, ibrutinib possesses immunomodulatory properties through targeting multiple signaling pathways. Understanding how this ancillary property of ibrutinib modifies the CLL microenvironment is crucial for further exploration of immune responses in this disease and devising future combination therapies. Here, we investigated the mechanisms underlying the immunomodulatory properties of ibrutinib. In peripheral blood samples collected prospectively from CLL patients treated with ibrutinib monotherapy, we observed selective and durable downregulation of PD-L1 on CLL cells by 3 months post-treatment. Further analysis showed that this effect was mediated through inhibition of the constitutively active signal transducer and activator of transcription 3 (STAT3) in CLL cells. Similar downregulation of PD-1 was observed in CD4+ and CD8+ T cells. We also demonstrated reduced interleukin (IL)-10 production by CLL cells in patients receiving ibrutinib, which was also linked to suppression of STAT3 phosphorylation. Taken together, these findings provide a mechanistic basis for immunomodulation by ibrutinib through inhibition of the STAT3 pathway, critical in inducing and sustaining tumor immune tolerance. The data also merit testing of combination treatments combining ibrutinib with agents capable of augmenting its immunomodulatory effects.

Characteristics, outcomes, prognostic factors and treatment of patients with T-cell prolymphocytic leukemia (T-PLL).

BACKGROUND: T-cell prolymphocytic leukemia (T-PLL) is a rare and aggressive disease. In this study, we report our experience from 119 patients with T-PLL. PATIENTS AND METHODS: We reviewed the clinico-pathologic records of 119 consecutive patients with T-PLL, who presented to our institution between 1990 and 2016. RESULTS: One hundred and nineteen patients with T-PLL were analysed. Complex karyotype and aberrations in chromosome 14 were seen in 65% and 52% patients, respectively. Seventy-five patients (63%) were previously untreated and 43 (37%) were initially treated outside our institution. Sixty-three previously untreated patients (84%) received frontline therapies. Overall, 95 patients (80%) have died. Median overall survival (OS) from diagnosis was 19 months [95% confidence interval (CI) 16-26 months]. Using recursive partitioning (RP), we found that patients with hemoglobin < 9.3 g/dl, lactate dehydrogenase (LDH) ≥ 1668 IU/l, white blood cell ≥ 208 K/l and ß2M ≥ 8 mg/l had significantly inferior OS and patients with hemoglobin < 9.3 g/dl had inferior progression-free survival (PFS). In multivariate analysis, we identified that presence of pleural effusion [hazard ratio (HR) 2.08 (95% CI 1.11-3.9); P = 0.02], high LDH (≥ 1668 IU/l) [HR 2.5 (95% CI 1.20-4.24); P < 0.001)], and low hemoglobin (< 9.3 g/dl) [HR 0.33 (95% CI 0.14-0.75); P = 0.008] were associated with shorter OS. Fifty-five previously untreated patients received treatment with an alemtuzumab-based regimen (42 monotherapy and 13 combination with pentostatin). Overall response rate, complete remission rate (CR) for single-agent alemtuzumab and alemtuzumab combined with pentostatin were 83%, 66% and 82%, 73% respectively. In patients who achieved initial CR, stem cell transplantation was not associated with longer PFS and OS. CONCLUSION: Outcomes in T-PLL remain poor. Multicenter collaborative effort is required to conduct prospective studies.

Bendamustine added to allogeneic conditioning improves long-term outcomes in patients with CLL.

Bendamustine has shown a favorable safety profile when included in chemotherapy regimens for several types of lymphoma, including CLL. This study investigated the long-term effect of adding bendamustine to a conditioning regimen on survival, rate of engraftment, immune recovery and GvHD after allogeneic stem cell transplantation (alloSCT) in CLL patients. These outcomes were compared with the fludarabine, cyclophosphamide and rituximab (FCR) conditioning regimen. We reviewed the data for 89 CLL patients treated on three trials at our institution. Twenty-six (29%) patients received bendamustine, fludarabine and rituximab (BFR) and 63 (71%) received FCR. Patient characteristics were similar in both groups. Ten (38%) BFR-treated patients vs only two (3%) FCR-treated patients did not experience severe neutropenia (P=<0.001). The 3-year overall survival estimates for the BFR and FCR groups were 82 and 51% (P=0.03), and the 3-year PFS estimates were 63% and 27% (P=0.001), respectively. The 2-year treatment-related mortality was 8 and 23% and the incidence of grade 3 or 4 GvHD was 4% and 10%, respectively. This study is the first to report that addition of bendamustine to alloSCT conditioning for CLL patients is associated with improved survival and lower mortality, myelosuppression, and GvHD.

Incidence and prognostic impact of other cancers in a population of long-term survivors of chronic lymphocytic leukemia.

BACKGROUND: Information on the impact of other cancers (OCs) in long-term survivors (LTSs) of chronic lymphocytic leukemia (CLL) is limited. PATIENTS AND METHODS: Patients with CLL who survived >10 years were defined as LTSs of CLL. We calculated standardized incidence ratios (SIRs) to compare the incidence of OC in LTS of CLL versus the general population. A multivariable model was used to identify independent predictors of OC. Overall survival was analyzed as a function of the presence of OC. RESULTS: Among 797 LTSs of CLL, the cumulative frequency of OC was 36%, similar between 570 patients (72%) who required treatment for CLL (TRT) and 227 (28%) who remained untreated (UT). The most common OC in both groups was non-melanoma skin cancer, followed by prostate cancer, breast cancer, melanoma, lung cancer, and leukemia in TRT patients, and by prostate cancer, breast cancer, melanoma, lung cancer, and gastrointestinal tumors in the UT group. The SIR for all OC was 1.2 (P = 0.034). It was higher in males (SIR 1.31; P = 0.013) and patients <60 years (SIR 1.27; P = 0.027). A higher SIR was shown for secondary leukemia, melanoma, and head-and-neck cancers, whereas a lower SIR was found for gastrointestinal and bladder cancers. Independent predictors of OC development were advanced age, male gender, and lower platelets. The survival of patients with OC was 16.2 months and that of patients without OC 22.9 years. CONCLUSIONS: LTSs of CLL have an increased incidence of OC compared with the general population. CLL therapy is not a risk factor for OC in LTSs of CLL. The presence of an OC in these patients may be associated with shorter survival.

Outcomes for patients with chronic lymphocytic leukemia and acute leukemia or myelodysplastic syndrome.

Acute leukemia (AL) and myelodysplastic syndrome (MDS) are uncommon in chronic lymphocytic leukemia (CLL). We retrospectively identified 95 patients with CLL, also diagnosed with AL (n=38) or MDS (n=57), either concurrently (n=5) or subsequent (n=90) to CLL diagnosis and report their outcomes. Median number of CLL treatments prior to AL and MDS was 2 (0-9) and 1 (0-8), respectively; the most common regimen was purine analog combined with alkylating agent±CD20 monoclonal antibody. Twelve cases had no prior CLL treatment. Among 38 cases with AL, 33 had acute myelogenous leukemia (AML), 3 had acute lymphoid leukemia (ALL; 1 Philadelphia chromosome positive), 1 had biphenotypic and 1 had extramedullary (bladder) AML. Unfavorable AML karyotype was noted in 26, and intermediate risk in 7 patients. There was no association between survival from AL and number of prior CLL regimens or karyotype. Expression of CD7 on blasts was associated with shorter survival. Among MDS cases, all International Prognostic Scoring System (IPSS) were represented; karyotype was unfavorable in 36, intermediate in 6 and favorable in 12 patients; 10 experienced transformation to AML. Shorter survival from MDS correlated with higher risk IPSS, poor-risk karyotype and increased number of prior CLL treatments. Overall, outcomes for patients with CLL subsequently diagnosed with AL or MDS were very poor; AL/MDS occurred without prior CLL treatment. Effective therapies for these patients are desperately needed.

A phase II open-label study of the intravenous administration of homoharringtonine in the treatment of myelodysplastic syndrome.

Homoharringtonine is an alkaloid inhibitor of protein synthesis with activity in myeloid malignancies. We report a phase II pilot study of homoharringtonine in myelodysplastic syndrome (MDS). Induction consisted of homoharringtonine at 2.5 mg/m(2) via continuous infusion for 7 days. Maintenance was given every 4 weeks. Nine patients were enrolled: five with refractory anaemia with excess blasts, two with refractory anaemia with excess blasts in transformation, one each with refractory anaemia and chronic myelomonocytic leukaemia respectively. Median age was 70 years (55-84) and 6 (66%) were male. Per International Prognostic Scoring System (IPSS) two patients were intermediate-1, five intermediate-2 and two high-risk. Median chemotherapy courses were one (1-3). One patient (11%) responded with complete haematological and cytogenetic remission after one course. Eight patients did not respond (four had stable disease, two progressed to acute leukaemia and two died during induction - from aspergillus pneumonia and intracerebral haemorrhage respectively). Grade 3/4 myelosuppression seen in 56% (5/9). Serious non-haematological toxicities included one case of grade 4 left bundle branch heart block and one grade 3 nephrotoxicity. Median time between courses was 42 days (35-72 days). In conclusion homoharringtonine might have clinical activity in some patients with MDS.

Selective, novel spleen tyrosine kinase (Syk) inhibitors suppress chronic lymphocytic leukemia B-cell activation and migration.

Syk is a protein tyrosine kinase that couples B-cell receptor (BCR) activation with downstream signaling pathways, affecting cell survival and proliferation. Moreover, Syk is involved in BCR-independent functions, such as B-cell migration and adhesion. In chronic lymphocytic leukemia (CLL), Syk becomes activated by external signals from the tissue microenvironment, and was targeted in a first clinical trial with R788 (fostamatinib), a relatively nonspecific Syk inhibitor. Here, we characterize the activity of two novel, highly selective Syk inhibitors, PRT318 and P505-15, in assays that model CLL interactions with the microenvironment. PRT318 and P505-15 effectively antagonize CLL cell survival after BCR triggering and in nurse-like cell-co-cultures. Moreover, they inhibit BCR-dependent secretion of the chemokines CCL3 and CCL4 by CLL cells, and leukemia cell migration toward the tissue homing chemokines CXCL12, CXCL13, and beneath stromal cells. PRT318 and P505-15 furthermore inhibit Syk and extracellular signal-regulated kinase phosphorylation after BCR triggering. These findings demonstrate that the selective Syk inhibitors PRT318 and P505-15 are highly effective for inhibition of CLL survival and tissue homing circuits, and support the therapeutic development of these agents in patients with CLL, other B-cell malignancies and autoimmune disorders.

Soluble syndecan-1 (sCD138) as a prognostic factor independent of mutation status in patients with chronic lymphocytic leukemia.

Syndecan-1 (sCD138) is a transmembrane heparan sulfate-bearing proteoglycan expressed in epithelial cells as well as hematopoietic cells that demonstrate plasmacytoid differentiation. Higher levels of sCD138 correlate with poor outcome in myeloma. We examined the association of circulating sCD138 levels in plasma with clinical behavior in 104 patients with chronic lymphocytic leukemia. sCD138 levels were significantly higher in patients (median, 52.8 ng/ml; range, 13.4-252.7 ng/ml) than in healthy control subjects (median, 19.86; range, 14.49-33.14 ng/ml) (P < 0.01). Elevated sCD138 (>median, 52.8 ng/ml) was associated with significantly shorter survival (P = 0.0004); this association was independent of IgVH mutation status, beta2-microglobulin (beta2-M) level, and treatment history. Patients with mutated IgVH but high sCD138 levels (>52.8 ng/ml) had significantly shorter survival than those with mutated IgVH and lower levels of sCD138. Similarly, patients with unmutated IgVH but high sCD138 levels had significantly shorter survival than those with lower sCD138 levels and unmutated IgVH (P = 0.007). In a multivariate Cox regression model, only Rai stage, beta2-M, and sCD138 remained predictors of survival. These data suggest that sCD138 when combined with beta2-M and Rai stage, may replace the need for testing IgVH mutation status.

Treatment of B-cell chronic lymphocytic leukemia with nonchemotherapeutic agents: experience with single-agent and combination therapy.

Recent advances in purine analog-based combination chemotherapy and chemoimmunotherapy have significantly improved response rates and progression-free survival in patients with B-cell chronic lymphocytic leukemia (CLL). However, there are clinical scenarios in which purine analog-based treatment may not be appropriate, either because of the risk of toxicity in patients with comorbidity or because purine analog-based therapies are unlikely to achieve satisfactory responses. Novel, nonchemotherapeutic treatment regimens are becoming increasingly important in these patients, as well as in patients in whom combination chemotherapy-based treatment has failed or resulted in relapse. Nonchemotherapeutic agents include monoclonal antibodies, glucocorticoids, immunomodulatory drugs, drugs with specific intracellular molecular targets, vaccines and cellular immunotherapies. These agents use diverse mechanisms of action that may complement each other, therefore providing a scientific rationale to investigate combinations of these agents in the treatment of CLL. In this review, we will discuss current knowledge of available nonchemotherapeutic agents, available clinical experience with their use alone and in combination and how these approaches may affect outcomes in patients with CLL.

The natural history of fludarabine-refractory chronic lymphocytic leukemia patients who fail alemtuzumab or have bulky lymphadenopathy.

The natural history and outcome of salvage treatment for patients with fludarabine-refractory chronic lymphocytic leukemia who are either refractory to alemtuzumab ("double-refractory") or ineligible for alemtuzumab due to bulky lymphadenopathy ("bulky fludarabine-refractory") have not been described. We present the outcomes of 99 such patients (double-refractory n = 58, bulky fludarabine-refractory n = 41) undergoing their first salvage treatment at our center. Patients received a variety of salvage regimens including monoclonal antibodies (n = 15), single-agent cytotoxic drugs (n = 14), purine analogue combination regimens (n = 21), intensive combination chemotherapy (n = 36), allogeneic stem cell transplantation (SCT; n = 4), or other therapies (n = 9). Overall response to first salvage therapy other than SCT was 23%, with no complete responses. All four patients who underwent SCT as first salvage achieved complete remission. Early death (within 8 weeks of commencing first salvage) occurred in 13% of patients, and 54% of patients experienced a major infection during therapy. Overall survival was 9 months, with hemoglobin < 11 g/dL (hazard ratio 2.3), hepatomegaly (hazard ratio 2.4), and performance status > or = 2 (hazard ratio 1.9) being significant independent predictors of inferior survival.

The JAK-STAT pathway: a therapeutic target in hematological malignancies.

The development and function of hematopoietic cells depends on complex signaling pathways that are mediated by numerous cytokines and their receptors. The Janus kinase-signal transducer and activator of transcription (JAK-STAT) pathway is prominent both in normal hematopoiesis and in hematological malignancies. STATs are phosphorylated on tyrosine residues via JAK kinases and on serine residues by a variety of serine/threonine kinases. STATs then dimerize, translocate to the nucleus and bind DNA, initiating the transcription of target genes. STAT proteins mediate cell growth, differentiation, apoptosis, transformation, and other fundamental cell functions. Recently, mutations in the JAK2 gene driving the proliferation of the neoplastic clone have been identified in myeloproliferative disorders. In addition constitutive activation of the JAK-STAT pathway has been reported in various types of leukemias such as acute myelogenous leukemia, T-LGL leukemia, and multiple myeloma. This review describes the pathophysiological role of this pathway in hematological malignancies and the potential benefits of JAK-STAT inhibition.

Outcome in patients with nonleukemic granulocytic sarcoma treated with chemotherapy with or without radiotherapy.

Granulocytic sarcoma (GS) is an extramedullary tumor composed of immature myeloid cells. The objectives of this study were to describe the frequency, presenting characteristics, and survival in patients with nonleukemic GS by conducting a review of all untreated patients presenting to the MD Anderson Cancer Center between January 1990 and June 2002. In all, 21 patients with nonleukemic GS, 1520 patients with acute myeloid leukemia (AML), and 402 patients with high-risk myelodysplastic syndrome (MDS) were identified. GS occurred in 1.4% of patients with AML, and 1.1% of patients with AML or high-risk MDSs. The median patient age was 57 years (range, 7-81). Among 20 patients with available cytogenetics in tissue and/or bone marrow, six had chromosome 8 abnormalities. The median follow-up of surviving patients is 12 months (range, 7-75). In all, 20 patients were treated. Patients were treated with AML-type chemotherapy (n=16), chemotherapy and radiotherapy (n=3), or radiotherapy alone (n=1). A total of 13 patients (65%) achieved complete remission and one patient (5%) achieved partial remission. The median overall survival was 20 months (range, 1-75), median overall failure-free survival was 12 months (range, 1-75). The median survival of patients with chromosome 8 abnormalities was 12 months compared with 40 months of those without (P=0.17). Novel therapies for patients with GS are required.

Alemtuzumab: a novel monoclonal antibody.

Antibody-based treatment is a novel, effective management strategy for a variety of diseases. Alemtuzumab (CAMPATH) is an example of a monoclonal antibody (mAb) that was initially developed in the laboratory and has completed its journey by being approved for therapeutic use in humans. The main clinical applications of alemtuzumab include treatment of lymphoid malignancies, particularly chronic lymphocytic leukaemia (CLL) and T-cell prolymphocytic leukaemia (T-PLL) and prevention of graft versus host disease (GVHD) and graft rejection in bone marrow and solid organ transplant recipients. Alemtuzumab administration is accompanied by a characteristic first-dose reaction due to cytokine release that consists of fever, rigors, rash and, at times, dyspnea and hypotension. The most significant toxic effect is profound, prolonged lymphopenia and the subsequent increased risk of opportunistic infections; antibiotic prophylaxis is recommended for patients undergoing alemtuzumab treatment. Alemtuzumab has demonstrated clinical activity as a single agent and has an acceptable toxicity profile. It has significant therapeutic potential, especially against lymphoid malignancies.

High levels of vascular endothelial growth factor receptor-2 correlate with shortened survival in chronic lymphocytic leukemia.

Vascular endothelial growth factor receptor-2 (VEGFR-2), also termed KDR, is a high-affinity vascular endothelial growth factor (VEGF) receptor. VEGFR-2 plays a role in de novo blood vessel formation and hematopoietic cell development. Recently, we found that chronic lymphocytic leukemia (CLL) cells express high levels of VEGF. Therefore, we sought to investigate the role of VEGFR-2 in CLL. Using Western blot analysis, we first determined that VEGFR-2 is present in peripheral blood CLL cells. We then quantified the cellular levels of VEGFR-2 protein using a solid-phase radioimmunoanalysis in peripheral blood cells from 216 patients with CLL. As control, we used peripheral blood mononuclear cells (PBMNCs) from 31 hematologically normal individuals. The median of VEGFR-2 levels detected in the control samples was assigned a value of 1.0, and VEGFR-2 protein levels were normalized to the control median value. The median level of VEGFR-2 in CLL cells was 1.57. Patients with VEGFR-2 levels higher than 1.57 had elevated lymphocyte counts, severe anemia, elevated beta(2)-microglobulin and advanced-stage disease. Elevated VEGFR-2 levels were also associated with statistically significantly shorter survival (35.4 versus 60.1 months; P < 0.01). Our data indicate that cellular VEGFR-2 levels may serve as a prognostic factor in CLL. Further studies should investigate the biological implications of these findings and the effect of the interaction between VEGF and VEGFR-2 on CLL cell proliferation.

Thrombopoietin stimulates myelodysplastic syndrome granulocyte-macrophage and erythroid progenitor proliferation.

Thrombopoietin (TPO) has been successfully used to stimulate megakaryocyte progenitor proliferation and platelet production both in vitro and in vivo. We and other investigators have found that TPO also stimulates normal marrow colony-forming unit granulocyte-macrophage (CFU-GM) and burst-forming unit-erythroid (BFU-E) growth. In contrast to its effect on normal marrow precursors, TPO stimulates acute myelogenous leukemia (AML) progenitor proliferation in only 25% of the cases. Because the hematopoietic cells in Myelodysplastic syndrome (MDS) originate from both the normal and leukemic clones, we hypothesized that TPO may be a useful therapeutic agent for MDS. To test this hypothesis, we used fresh marrow samples taken from 14 MDS patients. We found that in the presence of fetal calf serum (FCS) and erythropoietin (EPO) TPO (5 to 40 ng/ml) MDS CFU-GM and BFU-E colony-forming cell proliferation were stimulated in a dose-dependent fashion by up to 103% and 93% respectively. This effect was similar to the stimulation obtained with optimal concentrations of granulocyte colony-stimulating factor (G-CSF), granulocyte-macrophage CSF (GM-CSF), or interleukin-3 (IL-3). Furthermore, TPO increased the colony-stimulatory effects of G-CSF, GM-CSF, IL-3, and stem cell factor (SCF) on MDS marrow cells. However, depletion of either T lymphocytes or adherent cells abrogated the effect of TPO, suggesting that the effect is not a direct one but is mediated through interaction with cytokines produced by accessory cells. Taken together, our data suggest that the therapeutic role of TPO in the management of MDS warrants further investigation.

Interferon-alpha plus low-dose cytosine arabinoside in advanced phase chronic myelogenous leukaemia patients.

Twenty-nine late chronic and accelerated phase chronic myelogenous leukaemia (CML) patients were entered in a pilot study designed to test the therapeutic efficacy of treatment with interferon-alpha (IFN-alpha) and low-dose cytosine arabinoside (ARA-C). IFN-alpha was administered at a dose of 2-10 x 10(6) IU/day and ARA-C at 15 mg/m2/day for 14 days each month. The treatment was well tolerated by 73% of the patients. Side effects were mainly asthenia, anorexia, anaemia and piastrinopenia. Haematological and cytogenetic responses were evaluated in the 19 patients who received more than 6 cycles. Four complete haematological response, 7 partial haematological response, 6 minor haematological response, 2 stable disease were obtained in this patient group. Two complete cytogenetic responses and 2 minor cytogenetic responses were detected in these patients. Suppression of secondary Ph' positive clones which appeared during the previous IFN-alpha treatment was documented in 3 accelerated phase patients after ARA-C was added to their IFN-alpha treatment. It would therefore seem that late chronic and accelerated phase CML patients benefit from combined IFN-alpha/ARA-C treatment and achieve haematological and cytogenetic responses not obtained during previous treatment without being exposed to undue toxicity. However, we cannot judge whether it offers any advantage in terms of survival.

Interferon-alpha-induced biologic modifications in patients with chronic myelogenous leukemia.

Serum neopterin (Np), beta 2-microglobulin (beta 2-M), and 2',5'-adenylate (2',5'A) levels and intracellular 2',5'A and human Mx (Hu-Mx) protein synthesis were measured in 20-24 chronic myeloid leukemia patients before and during 1 year of IFN-alpha treatment and in a further 8-9 patients before and at the end of the first and second treatment weeks only. Univariate analysis showed that IFN-alpha increased Np and 2',5'A serum levels and intracellular concentrations of 2',5'A and Hu-Mx significantly from the end of the first week to month 12 of therapy. The biologic marker profiles were similar in cytogenetic responders and nonresponders, as well as in patients treated with IFN-alpha early (< 12 months from diagnosis) or late (after > 12 months standard chemotherapy). Further, there were no differences in the short-term (first 14 days) or long-term (during 12 month therapy) induction of the biologic markers irrespective of whether IFN-alpha 2a or IFN-alpha 2b was given. Because multivariate analysis revealed no significant interactions between cytogenetic response, time to treatment, and type of IFN-alpha used, increments in intracellular 2',5'A and Hu-Mx protein were similar at all study times for all factor combinations tested. Np levels varied significantly only during the first 14 therapy days; changes in serum 2',5'A were never statistically significant.(ABSTRACT TRUNCATED AT 250 WORDS)

Interleukin 4 alters human bone marrow stroma and modulates its interaction with hematopoietic progenitors.

To investigate the functional activity of interleukin 4 (IL-4) on human marrow stroma formation, normal bone marrow (BM) samples were cultured in "Dexter-type" long-term cultures in the presence and absence of IL-4. IL-4 (0.001 to 1.0 micrograms/ml) added at the initiation of culture and once weekly when the cultures were fed effaced the culture architecture. In four-week old confluent cultures smooth muscle-like and endothelial-like cells were rare, the fibronectin network and cobblestone areas were absent, and a preponderance of monocyte-macrophages characterized the adherent layer. Exposure to IL-4 reduced the numbers of CD34+ cells, colony-forming unit granulocyte-macrophage (GFU-GM) cells and burst-forming unit-erythroid (BFU-E) cells in the adherent layer, and increased their numbers in the nonadherent layer. In five of eight IL-4-containing cultures the concentrations of macrophage colony-stimulating factor (M-CSF) were increased and in two of eight IL-4-treated cultures the concentrations of tumor necrosis factor-alpha (TNF-alpha) were significantly elevated as compared to those in control cultures, whereas there were no consistent differences in the levels of either IL-6 or transforming growth factor-beta (TGF-beta). IL-1 beta and granulocyte-macrophage CSF (GM-CSF) were not detected in any culture. These data suggest that IL-4 suppresses stroma formation and alters its structure and cellular composition.