An in vivo method for diversifying the functions of therapeutic antibodies.

V(D)J recombination generates mature B cells that express huge repertoires of primary antibodies as diverse immunoglobulin (Ig) heavy chain (IgH) and light chain (IgL) of their B cell antigen receptors (BCRs). Cognate antigen binding to BCR variable region domains activates B cells into the germinal center (GC) reaction in which somatic hypermutation (SHM) modifies primary variable region-encoding sequences, with subsequent selection for mutations that improve antigen-binding affinity, ultimately leading to antibody affinity maturation. Based on these principles, we developed a humanized mouse model approach to diversify an anti-PD1 therapeutic antibody and allow isolation of variants with novel properties. In this approach, component Ig gene segments of the anti-PD1 antibody underwent de novo V(D)J recombination to diversify the anti-PD1 antibody in the primary antibody repertoire in the mouse models. Immunization of these mouse models further modified the anti-PD1 antibodies through SHM. Known anti-PD1 antibodies block interaction of PD1 with its ligands to alleviate PD1-mediated T cell suppression, thereby boosting antitumor T cell responses. By diversifying one such anti-PD1 antibody, we derived many anti-PD1 antibodies, including anti-PD1 antibodies with the opposite activity of enhancing PD1/ligand interaction. Such antibodies theoretically might suppress deleterious T cell activities in autoimmune diseases. The approach we describe should be generally applicable for diversifying other therapeutic antibodies.

Interleukin-6 produced by enteric neurons regulates the number and phenotype of microbe-responsive regulatory T cells in the gut.

The immune and enteric nervous (ENS) systems monitor the frontier with commensal and pathogenic microbes in the colon. We investigated whether FoxP3+ regulatory T (Treg) cells functionally interact with the ENS. Indeed, microbe-responsive RORγ+ and Helios+ subsets localized in close apposition to nitrergic and peptidergic nerve fibers in the colon lamina propria (LP). Enteric neurons inhibited in vitro Treg (iTreg) differentiation in a cell-contact-independent manner. A screen of neuron-secreted factors revealed a role for interleukin-6 (IL-6) in modulating iTreg formation and their RORγ+ proportion. Colonization of germfree mice with commensals, especially RORγ+ Treg inducers, broadly diminished colon neuronal density. Closing the triangle, conditional ablation of IL-6 in neurons increased total Treg cells but decreased the RORγ+ subset, as did depletion of two ENS neurotransmitters. Our findings suggest a regulatory circuit wherein microbial signals condition neuronal density and activation, thus tuning Treg cell generation and immunological tolerance in the gut.

Incidence of Adjacent Segment Disease Requiring Reoperation After Lumbar Laminectomy Without Fusion: A Study of 398 Patients.

BACKGROUND: Adjacent segment disease (ASD) has not been described after laminectomy without fusion. OBJECTIVE: To determine the incidence of ASD after a 1- or 2-level lumbar laminectomy. METHODS: We retrospectively reviewed medical records of all patients who underwent 1- or 2-level, bilateral lumbar laminectomy without fusion for degenerative spinal disease (all follow-up ≥1 year). ASD was defined as clinical and/or radiographic evidence of degenerative spinal disease that required reoperation at the level above or below the index laminectomy. RESULTS: Of the 398 patients, the incidence of ASD requiring reoperation was 10%. The 39 ASD cases were almost equally distributed at L2-L3 (31%), L3-L4 (26%), and L5-S1 (31%), and to a lesser extent at L4-L5 (15%) (P = .51). The ASD incidences of 10% and 9% were equivalent after a 1- and 2-level laminectomy, respectively (P = .76). Rostral ASD was statistically more common than caudal ASD after both the 1- (P < .001) and 2- (P < .001) level laminectomy. Of the 39 ASD cases, 95% required laminectomy, 26% discectomy, and 49% fusion. Average time to ASD was 4 years. After a Kaplan-Meier analysis, time to reoperation for ASD was equivalent among the 1- and 2-level laminectomy cohorts (log-rank test, P = .13). CONCLUSION: The cumulative incidence of ASD requiring reoperation was 10% over a mean of 4 years. Both the 1- and 2-level laminectomy cohorts experienced equivalent incidences and rates of ASD. Of the 39 operations for ASD, about half required a fusion.

Concurrent neoadjuvant chemotherapy is an independent risk factor of stroke, all-cause morbidity, and mortality in patients undergoing brain tumor resection.

Neoadjuvant chemotherapy (NC) may be utilized for treatment of various tumors, and a proportion of patients on active NC may require resection of a primary or secondary brain tumor. The objective of this study is to examine the impact of NC on postoperative neurosurgical outcomes. Elective cranial neurosurgical patient data was obtained from the American College of Surgeons National Surgical Quality Improvement Program database between 2006 and 2012. The impact of NC on 30 day stroke, all-cause postoperative morbidity, and mortality were assessed. Adjusted odds ratios (OR) were estimated for stroke, overall morbidity, and mortality using a multivariable logistic regression model, accomplished in stepwise fashion, for patients receiving NC versus those not receiving NC. This study analyzed 3812 patients undergoing elective cranial surgery, with 152 on concurrent NC. NC patients had a complication rate of 23.68%, while patients not receiving NC had a lower complication rate at 17.65% (p=0.057). Multivariable regression analysis revealed that patients who received NC had significantly increased odds of developing a stroke with neurological deficit (OR 3.39; 95% confidence interval [CI] 1.37-8.40) and all-cause postoperative morbidity (OR 1.57; 95% CI 1.04-2.37) over the control group. Finally, the NC cohort demonstrated higher odds of mortality following surgery than their non-NC counterparts (OR 3.81; 95% CI 1.81-8.02). Ninety-two patients (2.41%) died within 30 days, of whom 10 (6.58%) were receiving NC versus 82 non-NC (2.24%) patients (p=0.001). Concurrent NC is associated with an increased risk of short-term stroke with neurological deficit, all-cause morbidity, and mortality in patients undergoing brain tumor resection.