Somatic hypermutation analysis in follicular lymphoma provides evidence suggesting bidirectional cell migration between lymph node and bone marrow during disease progression and relapse.

In follicular lymphoma, somatic hypermutation of the immunoglobulin heavy chain genes facilitates the identification of different lymphoma cell clones, and the construction of genealogical trees. To investigate the dissemination of lymphoma cells, and the role of bone marrow in disease progression, we simultaneously analyzed the somatic hypermutation patterns of lymph node and bone marrow specimens taken from three patients at onset and relapse of their disease. Immunoglobulin heavy chain genes were amplified by polymerase chain reaction, cloned and sequenced. Mutational pedigrees were constructed in a hierarchical order. When direct transition of one mutation pattern into that of a successor clones was not feasible, hypothetical predecessor clones were created, and a probability measurement calculation was introduced. Eighty-five sequenced clones were generated. The average mutation rates were 13.45% for the lymph node specimens, and 9.78% for the bone marrow ones. Forty-two hypothetical predecessor clones were introduced into inter-compartment pedigrees. The genealogical trees showed that early lymphoma clones with a low mutational load quickly migrate from lymph nodes into the bone marrow. Bi-directional lymphoma cell migration was detectable between the two compartments. In one case of follicular lymphoma, a clone identical to the initial lymph node clone was detected 2 years later in the bone marrow. The newly introduced algorithm allows the evaluation of both time and direction of follicular lymphoma cell migration. We found evidence that follicular lymphoma originates in the lymph node, and infiltrates the bone marrow early in the course of the disease. Moreover, inter-compartment migration between lymph nodes and bone marrow occurs in both directions

Thoracic radiotherapy PLUS durvalumab in elderly and/or frail NSCLC stage III patients unfit for chemotherapy: Employing optimized (hypofractionated) radiotherapy to foster durvalumab efficacy—The TRADE-hypo trial.

TPS8585 Background: Non-small cell lung cancer (NSCLC) is the most common cause of cancer death worldwide highlighting the importance of improving current therapeutic options. In particular, elderly and frail patients are not only underrepresented in clinical trials, but also frequently do not receive standard treatment regimens due to comorbidities. For example, patients with unresectable stage III NSCLC who are unfit for chemotherapy (CHT) do not benefit from the recent seminal therapy algorithm change for this disease, i.e. consolidation therapy with the immune checkpoint inhibitor (ICI) durvalumab after combined radiochemotherapy (RChT). Instead, these patients are treated with radiotherapy only, raising the serious concern of undertreatment. This issue is addressed by the TRADE-hypo clinical trial that investigates a novel therapy option for NSCLC stage III patients not capable of receiving CHT. To this end, thoracic radiotherapy (TRT) is administered together with durvalumab, employing the synergism created by the combination of restoring anti-tumor immune response by the ICI with the induction of immunogenicity by irradiation. The latter effect has been suggested to be further boosted by hypofractionated radiotherapy, which could also be more practicable for the patient. Taken these considerations into account, the TRADE-hypo trial addresses safety and efficacy of durvalumab therapy combined with either conventional or hypofractionated TRT. Methods: The TRADE-hypo trial is a prospective, randomized, open-label, multicentric phase II trial. Eligible patients are diagnosed with unresectable stage III NSCLC and not capable of receiving sequential RChT due to high vulnerability as reflected by a poor performance status (ECOG 2 or ECOG1 and CCI≥ 1) and/or high age (≥ 70)]. Two treatment groups are evaluated: Both receive durvalumab (1,5000 mg, Q4W) for up to 12 months. In the CON-group this is combined with conventionally fractionated TRT (30 x 2 Gy), while in the HYPO-group patients are treated with hypofractionated TRT (20 x 2.75 Gy). In the HYPO-arm, a safety stop-and-go lead-in phase precedes full enrollment. Here, patients are closely monitored with regard to toxicity (i.e., pneumonitis grade ≥ 3 within 8 weeks after TRT) in small cohorts of 6. The primary objective of the trial is safety and tolerability. As a primary efficacy endpoint, the objective response rate after 3 months will be evaluated. Further endpoints are additional parameters of safety and efficacy, as well as the comprehensive collection of biomaterials to be analyzed regarding treatment-induced changes and potential novel biomarkers. As of February 10, 2021, 9 patients of planned 88 patients have been enrolled in the TRADE-hypo trial. Clinical trial information: NCT04351256.TPS8585 Background: Non-small cell lung cancer (NSCLC) is the most common cause of cancer death worldwide highlighting the importance of improving current therapeutic options. In particular, elderly and frail patients are not only underrepresented in clinical trials, but also frequently do not receive standard treatment regimens due to comorbidities. For example, patients with unresectable stage III NSCLC who are unfit for chemotherapy (CHT) do not benefit from the recent seminal therapy algorithm change for this disease, i.e. consolidation therapy with the immune checkpoint inhibitor (ICI) durvalumab after combined radiochemotherapy (RChT). Instead, these patients are treated with radiotherapy only, raising the serious concern of undertreatment. This issue is addressed by the TRADE-hypo clinical trial that investigates a novel therapy option for NSCLC stage III patients not capable of receiving CHT. To this end, thoracic radiotherapy (TRT) is administered together with durvalumab, employing the synergism created by the combination of restoring anti-tumor immune response by the ICI with the induction of immunogenicity by irradiation. The latter effect has been suggested to be further boosted by hypofractionated radiotherapy, which could also be more practicable for the patient. Taken these considerations into account, the TRADE-hypo trial addresses safety and efficacy of durvalumab therapy combined with either conventional or hypofractionated TRT. Methods: The TRADE-hypo trial is a prospective, randomized, open-label, multicentric phase II trial. Eligible patients are diagnosed with unresectable stage III NSCLC and not capable of receiving sequential RChT due to high vulnerability as reflected by a poor performance status (ECOG 2 or ECOG1 and CCI≥ 1) and/or high age (≥ 70)]. Two treatment groups are evaluated: Both receive durvalumab (1,5000 mg, Q4W) for up to 12 months. In the CON-group this is combined with conventionally fractionated TRT (30 x 2 Gy), while in the HYPO-group patients are treated with hypofractionated TRT (20 x 2.75 Gy). In the HYPO-arm, a safety stop-and-go lead-in phase precedes full enrollment. Here, patients are closely monitored with regard to toxicity (i.e., pneumonitis grade ≥ 3 within 8 weeks after TRT) in small cohorts of 6. The primary objective of the trial is safety and tolerability. As a primary efficacy endpoint, the objective response rate after 3 months will be evaluated. Further endpoints are additional parameters of safety and efficacy, as well as the comprehensive collection of biomaterials to be analyzed regarding treatment-induced changes and potential novel biomarkers. As of February 10, 2021, 9 patients of planned 88 patients have been enrolled in the TRADE-hypo trial. Clinical trial information: NCT04351256

The tetraspanin CD9 mediates lateral association of MHC class II molecules on the dendritic cell surface

We have found that MHC class II (MHC II) molecules exhibit a distinctive organization on the dendritic cell (DC) plasma membrane. Both in DC lysates and on the surface of living cells, I-A and I-E molecules engaged in lateral interactions not observed on other antigen-presenting cells such as B blasts. Because DCs and B blasts express MHC II at comparable surface densities, the interaction was not due to simple mass action. Instead, it reflected the selective expression of the tetraspanin CD9 at the DC surface. I-A and I-E molecules coprecipitated with each other and with CD9. The association of heterologous MHC II molecules was abrogated in DCs from CD9(−/−) mice. Conversely, expression of exogenous CD9 in B cells induced MHC II interactions. CD9 is thus necessary for the association of heterologous MHC II, a specialization that would facilitate the formation of MHC II multimers expected to enhance T cell receptor stimulation by DCs