Concurrent immune checkpoint inhibition and selective immunosuppressive therapy in patients with immune-related enterocolitis

PURPOSE

Immune checkpoint inhibitor (ICI) therapy is often suspended because of immune-related enterocolitis (irEC). We examined the effect of resumption of ICIs with or without concurrent selective immunosuppressive therapy (SIT) on rates of symptom recurrence and survival outcomes.

METHODS

This retrospective, multicenter study examined patients who were treated with ICI and developed irEC requiring SIT (infliximab or vedolizumab) for initial symptom control or to facilitate steroid tapering between May 2015 and June 2020. After symptom resolution, patients were restarted either on ICI alone or on concurrent ICI and SIT at the discretion of the treating physicians. The associations between irEC recurrence and treatment group were assessed via univariate analyses and multivariate logistic regression. Cox proportional hazards model was used for survival analysis.

RESULTS

Of the 138 included patients who required SIT for initial irEC symptom control, 61 (44.2%) patients resumed ICI without concurrent SIT (control group) and 77 (55.8%) patients resumed ICI therapy with concurrent SIT: 33 with infliximab and 44 with vedolizumab. After symptom resolution, patients in the control group were more commonly restarted on a different ICI regimen (65.6%) compared with those receiving SIT (31.2%) (p<0.001). The total number of ICI doses administered after irEC resolution and ICI resumption was similar in both groups (four to five doses). Recurrence of severe colitis or diarrhea after ICI resumption was seen in 34.4% of controls compared with 20.8% of patients receiving concurrent SIT. Concurrent SIT was associated with reduced risk of severe irEC recurrence after ICI resumption in a multivariate logistic regression model (OR 0.34; 95% CI 0.13 to 0.92; p=0.034). There was no difference in survival outcomes between patients in the control group and patients concurrently treated with SIT.

CONCLUSION

After resolution of irEC symptoms, reinitiation of ICI with concurrent SIT is safe, reduces severe irEC recurrence, and has no negative impact on survival outcomes.

Systemic bevacizumab as salvage therapy for persistent severe bleeding and anemia in heyde syndrome following aortic valve replacement

Heyde syndrome is characterized by the co-occurrence of aortic stenosis and bleeding gastrointestinal angiodysplasias, often with acquired von Willebrand syndrome. Current management for bleeding includes hematologic support with red cell transfusion and intravenous iron and correction of aortic stenosis with valve replacement. However, persistent Heyde syndrome after valve replacement occurs in a significant minority of cases, and there is no accepted therapy for these patients. Given that the pathophysiology of angiodysplasia formation in Heyde syndrome involves dysregulated angiogenesis, targeting angiogenesis may be an effective therapeutic option. We describe two cases of persistent Heyde syndrome with severe bleeding and anemia in patients following aortic valve replacement who were treated with systemic bevacizumab, a monoclonal antibody directed against vascular endothelial growth factor. In both cases, treatment was successful, with resolution of bleeding, liberation from hematologic support, and normalization of hemoglobin. In addition to responding to therapy, neither patient had treatment-related adverse events (and both had recurrent anemia upon treatment discontinuation, further evidence of the therapeutic impact of bevacizumab). Additional investigation into the use of systemic antiangiogenic therapy for treatment of Heyde syndrome is warranted.

Update on Immune Checkpoint Inhibitor Enterocolitis

PURPOSE OF REVIEW

Immune checkpoint inhibitor (ICI) therapy revolutionized the treatment of multiple solid and hematologic malignancies. Yet, with it came profound inflammatory toxicities that mimic autoimmune diseases, termed immune-related adverse events (irAEs). Prominent among these is gastrointestinal inflammation, including a spectrum of gastritis, enteritis, and colitis. Here we synthesize an approach to immune checkpoint related enterocolitis (irEC) - including diagnostics and therapeutics - underpinned by new insights into the mechanism behind these phenomena.

RECENT FINDINGS

This review presents updated insights on how to approach irEC, including novel approaches to selective immunosuppressive therapy, the role of fecal microbiota transplant, and the underlying cellular mechanisms of irEC. This review provides an update on irEC diagnosis and therapy, with considerations of new therapies and special patient populations. The field of gastrointestinal irAEs requires additional investigation, which will ultimately provide the tools required for patients to continue to receive life-saving ICI therapy.

Immune checkpoint inhibitor-associated celiac disease

BACKGROUND

Rare cases of immune checkpoint inhibitor (ICI)-associated celiac disease (ICI-CeD) have been reported, suggesting that disruption of tolerance mechanisms by ICIs can unmask celiac disease (CeD). This study aims to characterize the clinicopathological and immunophenotypic features of ICI-CeD in comparison to ICI-associated duodenitis (ICI-Duo) and usual CeD.

METHODS

A medical and pathological records search between 2015 and 2019 identified eight cases of ICI-CeD, confirmed by tTG-IgA. Nine cases of ICI-Duo, 28 cases of moderate CeD, as well as 5 normal controls were used as comparison groups. Clinical information was collected from the electronic medical records. Immunohistochemistry for CD3, CD8, T-cell receptor gamma/delta (γδ), programmed death ligand 1 (PD-L1), and programmed death 1 (PD-1) were performed, with quantification of intraepithelial lymphocyte (IEL) subsets in three well-oriented villi. CD68, PD-L1, and PD-1 were assessed as a percentage of lamina propria surface area infiltrated by positive cells. Statistical significance was calculated by the Student's t-test and Fisher's exact test.

RESULTS

The eight patients with ICI-CeD (F:M=1:3) and nine patients with ICI-Duo (F:M=5:4) presented similarly with diarrhea (13/17) and abdominal pain (11/17) after a median of 1.6 months on ICI therapy. In patients with ICI-CeD, tTG-IgA ranged from 104 to >300 IU/mL. Histological findings in ICI-CeD and ICI-Duo were similar and included expansion of the lamina propria, active neutrophilic duodenitis, variably increased IELs, and villous blunting. Immunohistochemistry showed that the average number of IELs per 100 enterocytes is comparable between ICI-CeD and ICI-Duo, with increased CD3⁺ CD8⁺ T cells compared with normal duodenum but decreased γδ T cells compared with CeD. Average PD-L1 percentage was 9% in ICI-CeD and 18% in ICI-Duo, in comparison to <1% in CeD and normal duodenum; average PD-1 percentage was very low to absent in all cases (<3%). On follow-up, five patients with ICI-CeD improved on a gluten-free diet (GFD) as the sole therapeutic intervention (with down-trending tTG-IgA) while the other three required immunosuppression. All patients who developed ICI-Duo received immunosuppression with variable improvement in symptoms.

CONCLUSIONS

ICI-CeD resembles ICI-Duo clinically and histologically but shares the serological features and response to gluten withdrawal with classic CeD. Immunophenotyping of IELs in ICI-CeD and ICI-Duo also shows similar CD3, CD8, γδ T cell subsets, and PD-L1 populations, all of which differed quantitatively from usual CeD. We conclude that ICI-CeD is biologically similar to ICI-Duo and is likely a variant of ICI-Duo, but treatment strategies differ, with ICI-CeD often improving with GFD alone, whereas ICI-Duo requires systemic immunosuppression.

Arsenic toxicity manifesting as profuse watery diarrhea during induction therapy for acute promyelocytic leukemia

Arsenic trioxide (ATO) is generally well tolerated for treatment of APL. We present a patient with severe watery diarrhea and pancreatitis thought to be due to ATO toxicity in the setting of obesity and acute kidney injury. Future studies evaluating ATO levels in patients experiencing toxicities may help guide dose modifications.

Concurrent therapy with immune checkpoint inhibitors and TNFα blockade in patients with gastrointestinal immune-related adverse events

BACKGROUND

Immune checkpoint inhibitors (ICI) have demonstrated remarkable efficacy as cancer therapeutics, however, their use remains limited due to the development of immune related adverse events (irAEs). Immune related enterocolitis (irEC) is among the most common severe irAEs leading to the discontinuation of ICIs. Inhibitors of tumor necrosis factor alpha (anti-TNFα) have been used to treat irEC. Recent animal studies have shown that concurrent treatment with anti-TNFα and ICIs improves tumor responses and decreases colitis severity. This approach has not yet been studied in prospective trials in humans. Here we describe, for the first time, the outcomes of patients who were treated concurrently with anti-TNFα and one or two ICIs.

CASE PRESENTATIONS

Five patients with different primary malignancies were treated with ipilimumab/nivolumab (2 patients), pembrolizumab (1 patient), ipilimumab (1 patient), or cemiplimab (1 patient). All patients developed irEC within 40 days of their first ICI dose. The patients presented with a combination of upper and lower gastrointestinal symptoms and subsequently underwent upper endoscopy and/or lower endoscopy. Endoscopy results demonstrated a spectrum of acute inflammatory changes across the gastrointestinal tract. Steroid therapy was used as first line treatment. To prevent prolonged steroid use and recurrence of gastrointestinal inflammation after resumption of cancer therapy, patients were treated concurrently with infliximab and ICI. Patients tolerated further ICI therapy with no recurrence of symptoms. Repeat endoscopies showed resolution of acute inflammation and restaging imaging showed no cancer progression.

CONCLUSIONS

Concurrent treatment with anti-TNFα and ICI appears to be safe, facilitates steroid tapering, and prevents irEC. Prospective clinical trials are needed to assess the outcomes of this treatment modality.

Human RELA haploinsufficiency results in autosomal-dominant chronic mucocutaneous ulceration

Badran et al. demonstrate an essential contribution of biallelic RELA expression in protecting stromal and epithelial cells from TNF-mediated cell death in patients with chronic mucocutaneous ulceration.

The treatment of chronic mucocutaneous ulceration is challenging, and only some patients respond selectively to inhibitors of tumor necrosis factor-α (TNF). TNF activates opposing pathways leading to caspase-8–mediated apoptosis as well as nuclear factor κB (NF-κB)–dependent cell survival. We investigated the etiology of autosomal-dominant, mucocutaneous ulceration in a family whose proband was dependent on anti-TNF therapy for sustained remission. A heterozygous mutation in RELA, encoding the NF-κB subunit RelA, segregated with the disease phenotype and resulted in RelA haploinsufficiency. The patients’ fibroblasts exhibited increased apoptosis in response to TNF, impaired NF-κB activation, and defective expression of NF-κB–dependent antiapoptotic genes. Rela^+/− mice have similarly impaired NF-κB activation, develop cutaneous ulceration from TNF exposure, and exhibit severe dextran sodium sulfate–induced colitis, ameliorated by TNF inhibition. These findings demonstrate an essential contribution of biallelic RELA expression in protecting stromal cells from TNF-mediated cell death, thus delineating the mechanisms driving the effectiveness of TNF inhibition in this disease.

Leucine-rich repeat containing 8A (LRRC8A)-dependent volume-regulated anion channel activity is dispensable for T-cell development and function

BACKGROUND

Leucine-rich repeat containing 8A (LRRC8A) is an ubiquitously expressed transmembrane protein with 17 leucine-rich repeats (LRRs) at its C-terminal end and is an essential component of the volume-regulated anion channel (VRAC), which controls cellular volume. A heterozygous mutation in LRRC8A that truncates the 2 terminal LRRs was reported in a patient with agammaglobulinemia and absent B cells and was demonstrated to exert a dominant negative effect on T- and B-cell development in mice. Lrrc8a^-/- mice have severely defective T-cell development and function. It is not known whether the T- and B-cell defects caused by LRRC8A deficiency are caused by loss of VRAC activity.

OBJECTIVE

We sought to determine whether VRAC activity is required for normal T-cell development and function.

METHODS

VRAC activity was examined by using patch-clamp analysis. Flow cytometry was used to examine T-cell development. T-cell proliferation, cytokine secretion, and antibody titers were measured by using standard techniques.

RESULTS

We demonstrate that the spontaneous mouse mutant ébouriffé (ebo/ebo) harbors a homozygous 2-bp frameshift mutation in Lrrc8a that truncates the 15 terminal LRRs of LRRC8A. The Lrrc8a^ebo mutation does not affect protein expression but drastically diminishes VRAC activity in T cells. ebo/ebo mice share features with Lrrc8a^-/- mice that include curly hair, infertility, reduced longevity, and kidney abnormalities. However, in contrast to Lrrc8a^-/- mice, ebo/ebo mice have normal T-cell development and function and intact antibody response to T-dependent antigen.

CONCLUSION

LRRC8A-dependent VRAC activity is dispensable for T-cell development and function.

Mutations in pyrin masquerading as a primary immunodeficiency

Whole exome sequencing is increasingly used in the diagnosis of primary immunodeficiencies due to the overlapping and atypical presentations of these disorders. We report two patients who presented with recurrent infections and early onset colitis. They were investigated by whole exome sequencing due to suspicion of primary immunodeficiency and found to have mutations in pyrin known to cause familial Mediterranean fever.

Effect of Interleukins on Antibody Production by Epstein-Barr Virus Transformed B Cells

During the past few decades, monoclonal antibodies (MAbs) have become an increasingly used tool in diagnostics, therapeutics, and biomedical research. Several methods have been employed to produce MAbs, one of which is the immortalization of B cells by Epstein-Barr virus (EBV). Despite its simplicity, this procedure was never routinely adopted due to its poor efficiency and short-lived antibody (Ab) production. Various adjustments to the basic procedure were introduced, including the addition of certain cytokines and CpG oligodeoxynucleotides, which were shown to improve EBV infectivity and cloning efficiency. The objective of this study was to manipulate culture conditions of the EBV-transformed human lymphocytes, lymphoblastoid cell lines (LCLs), by the timely addition of stimuli including CpG and various interleukins. Such manipulations are aimed at improving LCL proliferative activity and enhancing the cell lines' immortalization potential as well as their Ab production. To accomplish this, IgG(+) B cells were isolated from peripheral blood of a hepatitis B vaccinated, anti-HB Ab-positive volunteer. These cells were infected with EBV and incubated in the presence of CpG DNA 2006 motifs, recombinant human interleukin-2 (rhIL-2), rhIL-4, rhIL-6, and rhIL-21, individually and in combinations. Cells were then restimulated for 2 weeks with the same ILs. The effect of these ILs on anti-HB Ab production and the proliferation of the EBV-transformed lymphocytes were investigated. The current study demonstrates that treatment of LCL cultures with rhIL-2, rh-IL4, rhIL-6, and rhIL-21, individually and in combination, increased to varying degrees the proliferative activity and Ab production of these cells. The addition of IL-4 alone was able to sustain increase in anti-HB Ab despite IL-4 withdrawal. This study suggests that with further optimization ILs can have an enhancing effect on LCL immortalization potential and Ab production capacity.

Combined immunodeficiency due to a homozygous mutation in ORAI1 that deletes the C-terminus that interacts with STIM 1

ORAI1 is the pore-forming subunit of the calcium release-activated calcium channel responsible for calcium influx into cells triggered by endoplasmic reticulum store depletion. We report here a patient with severe combined immunodeficiency and absent store-operated calcium entry due to a novel mutation in ORAI1 that results in the expression of a C-terminally truncated protein that abolishes ORAI1 binding to STIM1.

Pseudomonas aeruginosa PAO1 adapted to 2-phenoxyethanol shows cross-resistance to dissimilar biocides and increased susceptibility to antibiotics

The growth adaptability to increasing concentration of the biocide 2-phenoxyethanol (PE) was determined in Pseudomonas aeruginosa PAO1 (P.a.) as part of efforts to understand and control the biocide tolerance and its effect on cross-resistance to other biocides and resistance to antibiotics. After repeated subculturing in media containing increasing sub-minimum-inhibitory PE concentration, P.a. exhibited an adaptive resistance indicated by two-fold increase in MIC at the 10th passage. The resistance was stable and remained after passaging the strain in further 7 successive passages in PE-free growth media. The strain showed cross-resistance towards dissimilar biocides and displayed increased susceptibility to antibiotics, which was not influenced by the presence of the efflux inhibitor 'carbonyl cyanide m-chlorophenyl hydrazone'. Outer membranes of adapted strain showed altered protein profile when examined by SDS-PAGE.