CD8 effector T cells enhance teclistamab response in BCMA-exposed and -naïve multiple myeloma

ABSTRACT

Teclistamab, a B-cell maturation antigen (BCMA)- and CD3-targeting bispecific antibody, is an effective novel treatment for relapsed/refractory multiple myeloma (R/RMM), but efficacy in patients exposed to BCMA-directed therapies and mechanisms of resistance have yet to be fully delineated. We conducted a real-world retrospective study of commercial teclistamab, capturing both clinical outcomes and immune correlates of treatment response in a cohort of patients (n = 52) with advanced R/RMM. Teclistamab was highly effective with an overall response rate (ORR) of 64%, including an ORR of 50% for patients with prior anti-BCMA therapy. Pretreatment plasma cell BCMA expression levels had no bearing on response. However, comprehensive pretreatment immune profiling identified that effector CD8+ T-cell populations were associated with response to therapy and a regulatory T-cell population associated with nonresponse, indicating a contribution of immune status in outcomes with potential utility as a biomarker signature to guide patient management.

Sustained Minimal Residual Disease Negativity in Multiple Myeloma is Associated with Stool Butyrate and Healthier Plant-Based Diets

PURPOSE

Sustained minimal residual disease (MRD) negativity is associated with long-term survival in multiple myeloma. The gut microbiome is affected by diet, and in turn can modulate host immunity, for example through production of short-chain fatty acids including butyrate. We hypothesized that dietary factors affect the microbiome (abundance of butyrate-producing bacteria or stool butyrate concentration) and may be associated with multiple myeloma outcomes.

EXPERIMENTAL DESIGN

We examined the relationship of dietary factors (via a food frequency questionnaire), stool metabolites (via gas chromatography-mass spectrometry), and the stool microbiome (via 16S sequencing - α-diversity and relative abundance of butyrate-producing bacteria) with sustained MRD negativity (via flow cytometry at two timepoints 1 year apart) in myeloma patients on lenalidomide maintenance. The Healthy Eating Index 2015 score and flavonoid nutrient values were calculated from the food frequency questionnaire. The Wilcoxon rank sum test was used to evaluate associations with two-sided P < 0.05 considered significant.

RESULTS

At 3 months, higher stool butyrate concentration (P = 0.037), butyrate producers (P = 0.025), and α-diversity (P = 0.0035) were associated with sustained MRD negativity. Healthier dietary proteins, (from seafood and plants), correlated with butyrate at 3 months (P = 0.009) and sustained MRD negativity (P = 0.05). Consumption of dietary flavonoids, plant nutrients with antioxidant effects, correlated with stool butyrate concentration (anthocyanidins P = 0.01, flavones P = 0.01, and flavanols P = 0.02).

CONCLUSIONS

This is the first study to demonstrate an association between a plant-based dietary pattern, stool butyrate production, and sustained MRD negativity in multiple myeloma, providing rationale to evaluate a prospective dietary intervention.

Circulating neutrophil CD18 receptor expression and ischemic flap neutrophil infiltration in a guinea pig model

This article demonstrates a correlation between circulating neutrophil CD18 expression, neutrophil infiltration, and varying periods of ischemia induced in guinea pig island skin flaps. Fifty adult female Hartley guinea pigs were equally separated into a control group, a sham group, and ischemic groups of 2, 4, and 10 hours. All, except those in the control group, had single guinea pig island flank skin flaps raised. Systemic neutrophil surface receptor (CD18) expression was analyzed with monoclonal antibodies, and flap skin biopsy specimens were analyzed for neutrophil infiltration. The results show that neutrophil counts and receptor detection increase as flap ischemia increases. However, a trend toward declining receptor expression was observed in the 10-hour ischemic group. In conclusion, systemic neutrophil adhesion receptor upregulation is correlated with cutaneous flap neutrophil infiltration and ischemia-reperfusion injury in a guinea pig model. A trend toward declining receptor expression with advanced ischemia was observed.

Circulating Neutrophil CD18 Receptor Expression and Ischemic Flap Neutrophil Infiltration in a Guinea Pig Model

This article demonstrates a correlation between circulating neutrophil CD18 expression, neutrophil infiltration, and varying periods of ischemia induced in guinea pig island skin flaps. Fifty adult female Hartley guinea pigs were equally separated into a control group, a sham group, and ischemic groups of 2, 4, and 10 hours. All, except those in the control group, had single guinea pig island flank skin flaps raised. Systemic neutrophil surface receptor (CD18) expression was analyzed with monoclonal antibodies, and flap skin biopsy specimens were analyzed for neutrophil infiltration. The results show that neutrophil counts and receptor detection increase as flap ischemia increases. However, a trend toward declining receptor expression was observed in the 10-hour ischemic group. In conclusion, systemic neutrophil adhesion receptor upregulation is correlated with cutaneous flap neutrophil infiltration and ischemia-reperfusion injury in a guinea pig model. A trend toward declining receptor expression with advanced ischemia was observed.

In vivo correlation of neutrophil receptor expression, ischemia-reperfusion injury, and selective 5-lipoxygenase inhibition in guinea pigs

OBJECTIVE

To determine whether selective 5-lipoxygenase (5-LO) inhibition decreases expression of adhesion molecules (beta2 integrins) on systemic neutrophils, decreases neutrophil infiltration in ischemic flap tissue, and improves flap survival.

DESIGN

A randomized, controlled study of 91 adult female Hartley guinea pigs divided into 3 survival groups, 4 neutrophil assay groups, 1 sham group, and 1 control group. Ischemia of varying duration and reperfusion was induced in island flank skin flaps. The treated groups received zileuton, a 5-LO inhibitor, orally during flap ischemia. After reperfusion, systemic neutrophil receptor expression, neutrophil infiltration, and flap survival were measured. Surface receptor molecules on neutrophils from whole blood samples obtained via transcardiac puncture were analyzed using monoclonal antibodies and cell-associated fluorescence. Neutrophil infiltration into a distal 1 cm2 of flap tissue was assessed using myeloperoxidase antibodies. Flap survival was determined within 7 days of surgery.

RESULTS

Untreated flaps with 10 hours of ischemia underwent total necrosis. Treated 2- and 10-hour ischemic flaps survived intact. A significant main effect of the drug treatment was detected using analysis of variance (P<.001). Neutrophil receptor detection in the untreated groups undergoing 2 and 10 hours of ischemia was significantly increased compared with that in the treated groups with the same ischemia times. Skin neutrophil infiltration was significantly decreased in the treated groups.

CONCLUSIONS

Systemic administration of a 5-LO inhibitor is effective in reducing ischemia-reperfusion injury in flap tissue. Our data indicate that there is a significant reduction in neutrophil receptor expression with administration of 5-LO, reducing the priming of systemic neutrophils from circulating cytokines.

Systemic neutrophil intrinsic 5-lipoxygenase activity and CD18 receptor expression linked to reperfusion injury

OBJECTIVE

To determine if systemic neutrophil intrinsic 5-lipoxygenase (5-LO) inhibition correlates with decreased expression of surface adhesion molecules and attenuation of ischemia-reperfusion (i/r) injury in guinea pig island skin flaps.

METHODS

Eighty-one adult female Hartley guinea pigs were divided into one control group, three 2-hour ischemia groups, and four 10-hour ischemia groups. Island dorsal skin flaps were developed (except in the control group), and 2 hours before reperfusion, zileutin (a 5-LO inhibitor) or vehicle was administered orally. Postreperfusion systemic neutrophil receptor expression, neutrophil flap infiltration, and flap survival were measured. Neutrophils from whole blood were analyzed for CD18 containing surface receptor expression using monoclonal antibodies and cell associated fluorescence. Neutrophil infiltration into a distal centimeter squared of flap tissue was assessed using myeloperoxidase antibodies, and flap survival was determined within 7 days postoperatively.

RESULTS

Flaps in the treated 2- and 10-hour ischemic groups survived totally intact, while the untreated 10-hour ischemic flaps underwent total necrosis. A significant main effect of the drug was detected using analysis of variance (ANOVA) (P =.0001). Surface receptor detection and neutrophil infiltration were significantly increased in the untreated animals.

CONCLUSIONS

Zileuton, a 5-LO inhibitor, reduces adhesion receptor expression on systemic neutrophils and attenuates i/r injury. Systemic neutrophil intrinsic 5-LO activity and CD18 receptor expression are linked to reperfusion injury and may be fundamental events in its pathogenesis.

Phenol amplifies complement-fixing activity and induces IgG-precipitating activity in grain-dust extract

The use of phenol as a preservative in extracts of grain dust was found to be associated with an amplification of complement-fixing activity and the appearance of IgG-precipitating activity. Both activities were absorbed by IgG, suggesting that they were due to a single material. Phenol itself neither fixed complement nor formed a precipitate with IgG. 14C-labeled phenol was incorporated into the IgG precipitating material. Both the amplification of complement-fixing activity and the appearance of IgG-precipitating activity in phenol-containing grain-dust extract were dependent on the presence of air and were inhibited by heating the extract before phenol addition. One interpretation of these results is that a component of grain-dust extract, possibly an enzyme, oxidatively modifies phenol to a form that fixes complement and precipitates IgG. The modified material demonstrates properties of a polyphenol (tannin).

Time course of morphometric changes after acute allergic bronchoconstriction in the guinea pig

Experimental allergic bronchoconstriction was induced in guinea pigs by passive sensitization with a standard dose of homologous antiserum followed by challenge with aerosolized antigen. Lungs were removed from animals at intervals of up to 6 days thereafter, and several parameters of the reaction were assessed morphometrically by comparison with lungs from unsensitized guinea pigs. We determined all changes in volume of the lung tissue resulting from fixation through to the preparation of histologic sections, but no significant differences were observed between the time course subgroups. The size of both large and small airways was assessed by a point-counting technique, as well as by measurement of the percentage of the diameter of the airways contributed by the mean thickness of the muscular layer. Maximal bronchoconstriction was observed morphometrically to correspond with the peak of a response as determined clinically by the use of a strain gauge around the chest. This was followed by a return to normal of the airway size. The number of mast cells and eosinophils around large and small airways, around branches of the pulmonary artery and in random fields of the lung parenchyma was tabulated. The maximal decrease in mast cells was seen in animals which died immediately following challenge, but the numbers were not restored to the control level even in animals which had survived for 6 days. The greatest increase in eosinophil response occurred in lungs obtained 10 min following challenge. This model will be of value in determining the effects at the tissue level of pharmacological inhibitors of this reaction.