PD-1 blockade in subprimed CD8 cells induces dysfunctional PD-1+CD38hi cells and anti-PD-1 resistance.

Understanding resistance to antibody to programmed cell death protein 1 (PD-1; anti-PD-1) is crucial for the development of reversal strategies. In anti-PD-1-resistant models, simultaneous anti-PD-1 and vaccine therapy reversed resistance, while PD-1 blockade before antigen priming abolished therapeutic outcomes. This was due to induction of dysfunctional PD-1+CD38hi CD8+ cells by PD-1 blockade in suboptimally primed CD8 cell conditions induced by tumors. This results in erroneous T cell receptor signaling and unresponsiveness to antigenic restimulation. On the other hand, PD-1 blockade of optimally primed CD8 cells prevented the induction of dysfunctional CD8 cells, reversing resistance. Depleting PD-1+CD38hi CD8+ cells enhanced therapeutic outcomes. Furthermore, non-responding patients showed more PD-1+CD38+CD8+ cells in tumor and blood than responders. In conclusion, the status of CD8+ T cell priming is a major contributor to anti-PD-1 therapeutic resistance. PD-1 blockade in unprimed or suboptimally primed CD8 cells induces resistance through the induction of PD-1+CD38hi CD8+ cells that is reversed by optimal priming. PD-1+CD38hi CD8+ cells serve as a predictive and therapeutic biomarker for anti-PD-1 treatment. Sequencing of anti-PD-1 and vaccine is crucial for successful therapy.

Author Correction: PD-1 blockade in subprimed CD8 cells induces dysfunctional PD-1+CD38hi cells and anti-PD-1 resistance.

An amendment to this paper has been published and can be accessed via a link at the top of the paper.

90Y-daclizumab, an anti-CD25 monoclonal antibody, provided responses in 50% of patients with relapsed Hodgkin's lymphoma.

Despite significant advances in the treatment of Hodgkin's lymphoma (HL), a significant proportion of patients will not respond or will subsequently relapse. We identified CD25, the IL-2 receptor alpha subunit, as a favorable target for systemic radioimmunotherapy of HL. The scientific basis for the clinical trial was that, although most normal cells with exception of Treg cells do not express CD25, it is expressed by a minority of Reed-Sternberg cells and by most polyclonal T cells rosetting around Reed-Sternberg cells. Forty-six patients with refractory and relapsed HL were evaluated with up to seven i.v. infusions of the radiolabeled anti-CD25 antibody (90)Y-daclizumab. (90)Y provides strong ß emissions that kill tumor cells at a distance by a crossfire effect. In 46 evaluable HL patients treated with (90)Y-daclizumab there were 14 complete responses and nine partial responses; 14 patients had stable disease, and nine progressed. Responses were observed both in patients whose Reed-Sternberg cells expressed CD25 and in those whose neoplastic cells were CD25(-) provided that associated rosetting T cells expressed CD25. As assessed using phosphorylated H2AX (γ-H2AX) as a bioindicator of the effects of radiation exposure, predominantly nonmalignant cells in the tumor microenvironment manifested DNA damage, as reflected by increased expression of γ-H2AX. Toxicities were transient bone-marrow suppression and myelodysplastic syndrome in six patients who had not been evaluated with bone-marrow karyotype analyses before therapy. In conclusion, repeated (90)Y-daclizumab infusions directed predominantly toward nonmalignant T cells rosetting around Reed-Sternberg cells provided meaningful therapy for select HL patients.

Modulation of activity and conduction in single dorsal column axons by kilohertz-frequency spinal cord stimulation.

Kilohertz-frequency spinal cord stimulation (KHF-SCS) is a potential paresthesia-free treatment for chronic pain. However, the effects of KHF-SCS on spinal dorsal column (DC) axons and its mechanisms of action remain unknown. The objectives of this study were to quantify activation and conduction block of DC axons by KHF-SCS across a range of frequencies (1, 5, 10, or 20 kHz) and waveforms (biphasic pulses or sinusoids). Custom platinum electrodes delivered SCS to the T10/T11 dorsal columns of anesthetized male Sprague-Dawley rats. Single DC axons and compound action potentials were recorded during KHF-SCS to evaluate SCS-evoked activity. Responses to KHF-SCS in DC axons included brief onset firing, slowly accommodating asynchronous firing, and conduction block. The effects of KHF-SCS mostly occurred well above motor thresholds, but isolated units were activated at amplitudes shown to reduce behavioral sensitivity in rats. Activity evoked by SCS was similar across a range of frequencies (5-20 kHz) and waveforms (biphasic and sinusoidal). Stimulation at 1-kHz SCS evoked more axonal firing that was also more phase-synchronized to the SCS waveform, but only at amplitudes above motor threshold. These data quantitatively characterize the central nervous system activity that may modulate pain perception and paresthesia, and thereby provide a foundation for continued investigation of the mechanisms of KHF-SCS and its optimization as a therapy for chronic pain. Given the asynchronous and transient nature of DC activity, it is unlikely that the same mechanisms underlying conventional SCS (i.e., persistent, periodic DC activation) apply to KHF-SCS. NEW & NOTEWORTHY: Kilohertz-frequency spinal cord stimulation (KHF-SCS) is a new mode of SCS that may offer better pain relief than conventional SCS. However, the mechanism of action is poorly characterized, especially the effects of stimulation on dorsal column (DC) axons, which are the primary target of stimulation. This study provides the first recordings of single DC axons during KHF-SCS to quantify DC activity that has the potential to mediate the analgesic effects of KHF-SCS.

YM155 inhibits topoisomerase function.

YM155 (sepantronium bromide) has been evaluated in clinical trials as a survivin suppressant, but despite positive signals from early work, later studies were negative. Clarification of the mechanism of action of YM155 is important for its further development. YM155 affects cells in a cell cycle-specific manner. When cells are in G1, YM155 prevented their progression through the S phase, leaving the cells at G1/S when exposed to YM155. Passage through mitosis from G2 is also defective following YM155 exposure. In this study, YM155 did not behave like a typical DNA intercalator in viscosity, circular dichroism, and absorption spectroscopy studies. In addition, molecular modeling experiments ruled out YM155 DNA interaction to produce DNA intercalation. We show that YM155 inhibited topoisomerase 2α decatenation and topoisomerase 1-mediated cleavage of DNA, suggesting that YM155 inhibits the enzyme function. Consistent with these findings, DNA double-strand break repair was also inhibited by YM155.

Spinal sensory projection neuron responses to spinal cord stimulation are mediated by circuits beyond gate control.

Spinal cord stimulation (SCS) is a therapy used to treat intractable pain with a putative mechanism of action based on the Gate Control Theory. We hypothesized that sensory projection neuron responses to SCS would follow a single stereotyped response curve as a function of SCS frequency, as predicted by the Gate Control circuit. We recorded the responses of antidromically identified sensory projection neurons in the lumbar spinal cord during 1- to 150-Hz SCS in both healthy rats and neuropathic rats following chronic constriction injury (CCI). The relationship between SCS frequency and projection neuron activity predicted by the Gate Control circuit accounted for a subset of neuronal responses to SCS but could not account for the full range of observed responses. Heterogeneous responses were classifiable into three additional groups and were reproduced using computational models of spinal microcircuits representing other interactions between nociceptive and nonnociceptive sensory inputs. Intrathecal administration of bicuculline, a GABAA receptor antagonist, increased spontaneous and evoked activity in projection neurons, enhanced excitatory responses to SCS, and reduced inhibitory responses to SCS, suggesting that GABAA neurotransmission plays a broad role in regulating projection neuron activity. These in vivo and computational results challenge the Gate Control Theory as the only mechanism underlying SCS and refine our understanding of the effects of SCS on spinal sensory neurons within the framework of contemporary understanding of dorsal horn circuitry.

Markedly additive antitumor activity with the combination of a selective survivin suppressant YM155 and alemtuzumab in adult T-cell leukemia.

Adult T-cell leukemia (ATL) is an aggressive malignancy of CD4(+)CD25(+) lymphocytes caused by human T-cell lymphotropic virus type 1. Currently, there is no accepted curative therapy for ATL. In gene expression profiling, the antiapoptotic protein survivin (BIRC5) demonstrated a striking increase in ATL, and its expression was increased in patient ATL cells resistant to the anti-CD52 monoclonal antibody alemtuzumab (Campath-1H). In this study, we investigated the antitumor activity of a small-molecule survivin suppressant YM155 alone and in combination with alemtuzumab in a murine model of human ATL (MET-1). Both YM155 alone and its combination with alemtuzumab demonstrated therapeutic efficacy by lowering serum soluble IL-2Rα (sIL-2Rα) levels (P < .001) and prolonged the survival of tumor-bearing mice (P < .0001). Moreover, the combination of YM155 with alemtuzumab demonstrated markedly additive antitumor activity by significantly lowering serum sIL-2Rα levels and improving the survival of leukemia-bearing mice compared with monotherapy with either YM155 (P < .001) or alemtuzumab (P < .05). More significantly, all mice that received the combination therapy survived and were tumor free >6 months after treatment. Our data support a clinical trial of the combination of YM155 with alemtuzumab in ATL. This trial was registered at www.clinicaltrials.gov as #NCT00061048.

Phase 1 trial of IL-15 trans presentation blockade using humanized Mikß1 mAb in patients with T-cell large granular lymphocytic leukemia.

In the present study, Hu-Mikß1, a humanized mAb directed at the shared IL-2/IL-15Rß subunit (CD122) was evaluated in patients with T-cell large granular lymphocytic (T-LGL) leukemia. Hu-Mikß1 blocked the trans presentation of IL-15 to T cells expressing IL-2/IL-15Rß and the common γ-chain (CD132), but did not block IL-15 action in cells that expressed the heterotrimeric IL-15 receptor in cis. There was no significant toxicity associated with Hu-Mikß1 administration in patients with T-LGL leukemia, but no major clinical responses were observed. One patient who had previously received murine Mikß1 developed a measurable Ab response to the infused Ab. Nevertheless, the safety profile of this first in-human study of the humanized mAb to IL-2/IL-15Rß (CD122) supports its evaluation in disorders such as refractory celiac disease, in which IL-15 and its receptor have been proposed to play a critical role in the pathogenesis and maintenance of disease activity.

Modeling effects of spinal cord stimulation on wide-dynamic range dorsal horn neurons: influence of stimulation frequency and GABAergic inhibition.

Spinal cord stimulation (SCS) is a clinical therapy for chronic, neuropathic pain, but an incomplete understanding of the mechanisms underlying SCS contributes to the lack of improvement in SCS efficacy over time. To study the mechanisms underlying SCS, we constructed a biophysically based network model of the dorsal horn circuit consisting of interconnected dorsal horn interneurons and a wide-dynamic range (WDR) projection neuron and representations of both local and surround receptive field inhibition. We validated the network model by reproducing cellular and network responses relevant to pain processing including wind-up, A fiber-mediated inhibition, and surround receptive field inhibition. We then simulated the effects of SCS on the activity of the WDR projection neuron and found that the response of the model WDR neuron to SCS depends on the SCS frequency; SCS frequencies of 30-100 Hz maximally inhibited the model WDR neuron, while frequencies under 30 Hz and over 100 Hz excited the model WDR neuron. We also studied the impacts on the effects of SCS of loss of inhibition due to the loss of either GABA or KCC2 function. Reducing the influence of local and surround GABAergic interneurons by weakening their inputs or their connections to the WDR neuron and shifting the anionic reversal potential of the WDR neurons upward each reduced the range of optimal SCS frequencies and changed the frequency at which SCS had a maximal effect. The results of this study provide insights into the mechanisms of SCS and pave the way for improved SCS parameter selection.

Safety, efficacy, and pharmacokinetics/pharmacodynamics of daclizumab (anti-CD25) in patients with adult T-cell leukemia/lymphoma.

Interleukin-2 receptor α chain (CD25) is overexpressed in human T-cell leukemia virus 1 associated adult T-cell leukemia/lymphoma (ATL). Daclizumab a humanized monoclonal antibody blocks IL-2 binding by recognizing the interleukin-2 receptor α chain (CD25). We conducted a phase I/II trial of daclizumab in 34 patients with ATL. Saturation of surface CD25 on circulating ATL cells was achieved at all doses; however saturation on ATL cells in lymph nodes required 8 mg/kg. Up to 8 mg/kg of daclizumab administered every 3 weeks was well tolerated. No responses were observed in 18 patients with acute or lymphoma ATL; however, 6 partial responses were observed in 16 chronic and smoldering ATL patients. The pharmacokinetics/pharmacodynamics of daclizumab suggest that high-dose daclizumab would be more effective than low-dose daclizumab in treatment of lymphoid malignancies and autoimmune diseases (e.g., multiple sclerosis) since high-dose daclizumab is required to saturate IL-2R alpha in extravascular sites.

Increased serum soluble IL-15Rα levels in T-cell large granular lymphocyte leukemia.

Large granular lymphocyte (LGL) leukemia is a clonal lymphoproliferative disease of mature T and natural killer cells. The etiology of LGL leukemia is unknown. IL-15 is an inflammatory cytokine that stimulates T and natural killer cells and is critical for their survival and proliferation. IL-15 signals through a heterotrimeric receptor that is composed of a private receptor, IL-15Rα and IL-2/IL-15Rß and γ(c) shared with IL-2. Using a newly developed assay, we demonstrated increased levels of soluble IL-15Rα in the serum of patients with T-LGL leukemia. Furthermore, IL-15Rα mRNA levels were also up-regulated in the PBMCs of these patients. FACS analysis indicated that IL-15Rα was expressed both on monocytes as well as on some CD8+ leukemic cells of the patients. Interestingly, the mRNA levels of IFN-γ, a known inducer of IL-15Rα, were also up-regulated in patients' PBMCs. Moreover, PBMCs of some T-LGL patients proliferated at higher levels in response to exogenously added IL-15 compared with those of normal donors. In summary, our study demonstrated increased expression of IL-15Rα in T-LGL leukemia. It is conceivable that higher IL-15Rα expression may lower IL-15 response threshold in vivo and, therefore, may contribute to the pathogenesis of the disease.

Radiation therapy for the management of patients with HTLV-1-associated adult T-cell leukemia/lymphoma.

Human T-cell leukemia virus type 1-associated adult T-cell leukemia/lymphoma (ATL) typically has survivals measured in months with chemotherapy. One prior published series (1983-1991) assessed local radiotherapy for ATL. Ten consecutive patients with pathologically confirmed ATL treated with radiotherapy were reviewed. Subtypes included acute (n = 7), smoldering (n = 2), and lymphomatous (n = 1). Patients received an average of 2.5 systemic therapy regimens before radiotherapy. Twenty lesions (cutaneous = 10, nodal = 8, extranodal = 2) were treated to a mean of 35.4 Gy/2-3 Gy (range, 12-60 Gy). At 9.0-month mean follow-up (range, 0.1-42.0 months), all lesions symptomatically and radiographically responded, with in-field complete responses in 40.0% (nodal 37.5% vs. cutaneous 50.0%; P = .62). No patient experienced in-field progression. Nine patients developed new/progressive out-of-field disease. Median survival was 17.0 months (3-year survival, 30.0%). No Radiation Therapy Oncology Group acute grade ≥ 3 or any late toxicity was noted. This report is the first to use modern radiotherapy techniques and finds effective local control across ATL subtypes. Radiotherapy should be considered for symptomatic local progression of ATL.

FERM domain mutations induce gain of function in JAK3 in adult T-cell leukemia/lymphoma.

Adult T-cell leukemia/lymphoma (ATLL) is an incurable disease where most patients succumb within the first year of diagnosis. Both standard chemotherapy regimens and mAbs directed against ATLL tumor markers do not alter this aggressive clinical course. Therapeutic development would be facilitated by the discovery of genes and pathways that drive or initiate ATLL, but so far amenable drug targets have not been forthcoming. Because the IL-2 signaling pathway plays a prominent role in ATLL pathogenesis, mutational analysis of pathway components should yield interesting results. In this study, we focused on JAK3, the nonreceptor tyrosine kinase that signals from the IL-2R, where activating mutations have been found in diverse neoplasms. We screened 36 ATLL patients and 24 ethnically matched controls and found 4 patients with mutations in JAK3. These somatic, missense mutations occurred in the N-terminal FERM (founding members: band 4.1, ezrin, radixin, and moesin) domain and induced gain of function in JAK3. Importantly, we show that these mutant JAK3s are inhibited with a specific kinase inhibitor already in human clinical testing. Our findings underscore the importance of this pathway in ATLL development and offer a therapeutic handle for this incurable cancer.

CP-690,550, a therapeutic agent, inhibits cytokine-mediated Jak3 activation and proliferation of T cells from patients with ATL and HAM/TSP.

The retrovirus, human T-cell-lymphotrophic virus-1 (HTLV-I) is the etiologic agent of adult T-cell leukemia (ATL) and the neurological disorder HTLV-I-associated myelopathy/tropical spastic paraparesis (HAM/TSP). The HTLV-I-encoded protein tax constitutively activates interleukin-2 (IL-2), IL-9, and IL-15 autocrine/paracrine systems that in turn activate the Jak3 (Janus kinase 3)/STAT5 (signal transducers and activators of transcription 5) pathway, suggesting a therapeutic strategy that involves targeting Jak3. We evaluated the action of the Jak3 inhibitor CP-690,550 on cytokine dependent ex vivo proliferation that is characteristic of peripheral blood mononuclear cells (PBMCs) from select patients with smoldering or chronic subtypes of ATL, or from those with HAM/TSP whose PBMCs are associated with autocrine/paracrine pathways that involve the production of IL-2, IL-9, IL-15, and their receptors. CP-690,550 at 50 nM inhibited the 6-day ex vivo spontaneous proliferation of PBMCs from ATL and HAM/TSP patients by 67.1% and 86.4%, respectively. Furthermore, CP-690,550 inhibited STAT5 phosphorylation in isolated ATL T cells ex vivo. Finally, in an in vivo test of biological activity, CP-690,550 treatment of mice with a CD8 T-cell IL-15-transgenic leukemia that manifests an autocrine IL-15/IL-15Rα pathway prolonged the survival duration of these tumor-bearing mice. These studies support further evaluation of the Jak3 inhibitor CP-690,550 in the treatment of select patients with HTLV-I-associated ATL and HAM/TSP.

Safety, Tolerability, and Antitumor Activity of Zipalertinib Among Patients With Non-Small-Cell Lung Cancer Harboring Epidermal Growth Factor Receptor Exon 20 Insertions.

PURPOSE: Although several agents targeting epidermal growth factor receptor (EGFR) exon 20 insertions (ex20ins) have recently been approved by the US Food and Drug Administration, toxicities related to the inhibition of wild-type (WT) EGFR are common with these agents and affect overall tolerability. Zipalertinib (CLN-081, TAS6417) is an oral EGFR tyrosine kinase inhibitor (TKI) with a novel pyrrolopyrimidine scaffold leading to enhanced selectivity for EGFR ex20ins-mutant versus WT EGFR with potent inhibition of cell growth in EGFR ex20ins-positive cell lines. METHODS: This phase 1/2a study of zipalertinib enrolled patients with recurrent or metastatic EGFR ex20ins-mutant non-small-cell lung cancer (NSCLC) previously treated with platinum-based chemotherapy. RESULTS: Seventy-three patients were treated with zipalertinib at dose levels including 30, 45, 65, 100, and 150 mg orally twice a day. Patients were predominantly female (56%), had a median age of 64 years, and were heavily pretreated (median previous systemic therapies 2, range 1-9). Thirty six percent of patients had received previous non-ex20ins EGFR TKIs and 3/73 (4.1%) patients received previous EGFR ex20ins TKIs. The most frequently reported treatment-related adverse events of any grade included rash (80%), paronychia (32%), diarrhea (30%), and fatigue (21%). No cases of grade 3 or higher drug-related rash or diarrhea were observed at 100 mg twice a day or below. Objective responses occurred across all zipalertinib dose levels tested, with confirmed partial response (PR) observed in 28/73 (38.4%) response-evaluable patients. Confirmed PRs were seen in 16/39 (41%) response-evaluable patients at the dose of 100 mg twice a day. CONCLUSION: Zipalertinib has encouraging preliminary antitumor activity in heavily pretreated patients with EGFR ex20ins-mutant NSCLC, with an acceptable safety profile, including low frequency of high-grade diarrhea and rash.

Adaptive Kalman filtering for real-time mapping of the visual field.

This paper demonstrates the feasibility of real-time mapping of the visual field for clinical applications. Specifically, three aspects of this problem were considered: (1) experimental design, (2) statistical analysis, and (3) display of results. Proper experimental design is essential to achieving a successful outcome, particularly for real-time applications. A random-block experimental design was shown to have less sensitivity to measurement noise, as well as greater robustness to error in modeling of the hemodynamic impulse response function (IRF) and greater flexibility than common alternatives. In addition, random encoding of the visual field allows for the detection of voxels that are responsive to multiple, not necessarily contiguous, regions of the visual field. Due to its recursive nature, the Kalman filter is ideally suited for real-time statistical analysis of visual field mapping data. An important feature of the Kalman filter is that it can be used for nonstationary time series analysis. The capability of the Kalman filter to adapt, in real time, to abrupt changes in the baseline arising from subject motion inside the scanner and other external system disturbances is important for the success of clinical applications. The clinician needs real-time information to evaluate the success or failure of the imaging run and to decide whether to extend, modify, or terminate the run. Accordingly, the analytical software provides real-time displays of (1) brain activation maps for each stimulus segment, (2) voxel-wise spatial tuning profiles, (3) time plots of the variability of response parameters, and (4) time plots of activated volume.

Eradication of B-lineage cells and regression of lymphoma in a patient treated with autologous T cells genetically engineered to recognize CD19.

Adoptive transfer of genetically modified T cells is an attractive approach for generating antitumor immune responses. We treated a patient with advanced follicular lymphoma by administering a preparative chemotherapy regimen followed by autologous T cells genetically engineered to express a chimeric antigen receptor (CAR) that recognized the B-cell antigen CD19. The patient's lymphoma underwent a dramatic regression, and B-cell precursors were selectively eliminated from the patient's bone marrow after infusion of anti-CD19-CAR-transduced T cells. Blood B cells were absent for at least 39 weeks after anti-CD19-CAR-transduced T-cell infusion despite prompt recovery of other blood cell counts. Consistent with eradication of B-lineage cells, serum immunoglobulins decreased to very low levels after treatment. The prolonged and selective elimination of B-lineage cells could not be attributed to the chemotherapy that the patient received and indicated antigen-specific eradication of B-lineage cells. Adoptive transfer of anti-CD19-CAR-expressing T cells is a promising new approach for treating B-cell malignancies. This study is registered at www.clinicaltrials.gov as #NCT00924326.

Autocrine/paracrine cytokine stimulation of leukemic cell proliferation in smoldering and chronic adult T-cell leukemia.

Adult T-cell leukemia (ATL), a heterogeneous disease, can be divided into smoldering, chronic, lymphoma, and acute types clinically. In addition to different clinical manifestations, different stages of ATL have different molecular signatures. Here, we demonstrated that smoldering/chronic ATL peripheral blood mononuclear cells spontaneously proliferated ex vivo in a cytokine (interleukin-12 [IL-12]/IL-9/IL-15)-dependent manner, while acute-type ATL peripheral blood mononuclear cells did not proliferate or proliferated independent of cytokines. Smoldering/chronic ATL cells produced IL-2 and IL-9 in 6-day ex vivo cultures. Interestingly, the addition of an anti-IL-2R-α monoclonal antibody profoundly inhibited IL-9 expression, suggesting optimal expression of IL-9 was dependent on IL-2 signaling in these patients. To determine whether there would be autonomous proliferation of ATL leukemic cells, we purified leukemic cells from patients with smoldering/chronic ATL. Purified leukemic cells cultured alone produced IL-2/IL-9, and the downstream Janus kinase/signal transducer and activator of transcription pathway was activated. However, the leukemic cells did not proliferate independently, but required coculture with autologous monocytes to induce proliferation. Moreover, interaction between leukemic cells and monocytes was contact dependent, and major histocompatibility complex class II expression may have contributed to this interaction. In conclusion, our data provide evidence that there is autocrine/paracrine cytokine stimulation of leukemic cell proliferation in patients with smoldering/chronic ATL that could be targeted for treatment.

MicroRNA profiling of follicular lymphoma identifies microRNAs related to cell proliferation and tumor response.

BACKGROUND: MicroRNAs can play an important role in tumorigenesis through post-transcriptional regulation of gene expression, and are not well characterized in follicular lymphoma. DESIGN AND METHODS: MicroRNA profiles of enriched follicular lymphoma tumor cells from 16 patients were generated by assaying 851 human microRNAs. Tandem gene expression profiles were obtained for predicting microRNA targets. RESULTS: The expression of 133 microRNAs was significantly different (> 2-fold; P<0.05) between follicular lymphoma and follicular hyperplasia. Forty-four microRNAs in three groups generated a unique follicular lymphoma signature. Of these, ten microRNAs were increased (miR-193a-5p, -193b*, -345, -513b, -574-3p, -584, -663, -1287, -1295, and -1471), 11 microRNAs were decreased (miR-17*, -30a, -33a, -106a*, -141, -202, -205, -222, -301b, -431*, and -570), and 23 microRNAs formed a group that was increased in most cases of follicular lymphoma but showed lower expression in a subset of cases (let-7a, let-7f, miR-7-1*, -9, -9*, -20a, -20b, -30b, -96, -98, -194, -195, -221*, -374a, -374b, -451, -454, -502-3p, -532-3p, -664*, -1274a, -1274b, and -1260). Higher expression of this last group was associated with improved response to chemotherapy. Gene expression analysis revealed increased expression of MAPK1, AKT1, PRKCE, IL4R and DROSHA and decreased expression of CDKN1A/p21, SOCS2, CHEK1, RAD51, KLF4, BLIMP1 and IRF4 in follicular lymphoma. Functional studies indicated that CDKN1A/p21 and SOCS2 expression is directly regulated by miR-20a/-20b and miR-194, respectively. CONCLUSIONS: Follicular lymphoma is characterized by a unique microRNA signature, containing a subset of microRNAs whose expression correlate with response to chemotherapy. miR-20a/b and miR-194 target CDKN1A and SOCS2 in follicular lymphoma, potentially contributing to tumor cell proliferation and survival.

Vaccine-induced tumor-specific immunity despite severe B-cell depletion in mantle cell lymphoma.

The role of B cells in T-cell priming is unclear, and the effects of B-cell depletion on immune responses to cancer vaccines are unknown. Although results from some mouse models suggest that B cells may inhibit induction of T cell-dependent immunity by competing with antigen-presenting cells for antigens, skewing T helper response toward a T helper 2 profile and/or inducing T-cell tolerance, results from others suggest that B cells are necessary for priming as well as generation of T-cell memory. We assessed immune responses to a well-characterized idiotype vaccine in individuals with severe B-cell depletion but normal T cells after CD20-specific antibody-based chemotherapy of mantle cell lymphoma in first remission. Humoral antigen- and tumor-specific responses were detectable but delayed, and they correlated with peripheral blood B-cell recovery. In contrast, vigorous CD4(+) and CD8(+) antitumor type I T-cell cytokine responses were induced in most individuals in the absence of circulating B cells. Analysis of relapsing tumors showed no mutations or change in expression of target antigen to explain escape from therapy. These results show that severe B-cell depletion does not impair T-cell priming in humans. Based on these results, it is justifiable to administer vaccines in the setting of B-cell depletion; however, vaccine boosts after B-cell recovery may be necessary for optimal humoral responses.