Clinical Studies of Inflammatory Bowel Diseases

National Institute Of Allergy And Infectious Diseases

Investigators

Linked publications & trials

Abstract

During the current report period the Mucosal Immunity Section continued to conduct clinical research studies involving patients with inflammatory bowel disease (IBD) and with immunodeficiencies such as common variable immunodeficiency and X-linked agammaglobulinemia. In the area of IBD, we have focused on studies of IBD risk polymorphisms involving the LRRK2 gene region with the ultimate goal of exploring the capacity of LRRK2 kinase inhibitors to serve as a treatment modality in Crohn's disease. On this basis we are collaborating with Dr. Inga Peter and her colleagues at the Icahn Mt. Sinai Medical Center in New York who are developing LRRK2 kinase inhibitors with increased capacity to localize in the gastrointestinal tract. Dr. Peter and her colleagues also have access to a large IBD patient population that has been made available to us for study. Recently, it has been shown that LRRK kinase is active in the phosphorylation of NLRC4 and thus is a potential activator of the NLRC4 inflammasome. During this period we have studied the capacity of DCs generated from peripheral blood of Crohn's disease sent to us by our collaborators at Icahn Mt. Sinai Medical Center to respond to NLRC4 stimulation in the absence and presence of a LRRK2 kinase inhibitors, included inhibitors newly developed at Icahn/Mt Sinai. Using unique methods of assessing NLRC4 inflammasome activation we showed that patient DCs produce significantly greater amounts of IL-1beta and IL-18 as a result of NlRC4 stimulation than control individuals. In addition, patient DC IL-1beta production declines in the presence of an LRRK2 inhibitor whereas control DC does not. Finally, neither patient nor control DC IL-18 production decreases in the presence of inhibitor. These studies show that LRRK2 kinase inhibition has a selective down-regulatory effect on NLRC4 inflammasome activity that preserves the anti-inflammatory function of IL-18. In this period, we continued clinical studies of the safety and and immunologic effects of the administration of vorinostat, a histone deacetylase (HDAC) inhibitor, in patients with treatment-resistent Crohn's disease. To date, we have enrolled 3 patients. Patient 1 experienced significant clinical amelioration of Crohn’s disease symptoms and achieved clinical remission (CDAI score < 150); this was accompanied by normalization of albumin and protein levels and improvement in alpha1-anti-trypsin levels. Immunologic evaluation revealed increases in intestinal RORt+/ FoxP3+ suppressor cells that persisted for 6 months after cessation of Vorinostat treatment. Patient 2 was found ineligible for participation in the treatment phase of the study. Given the results observed in patient 1, the study was modified to offer continuance of treatment with vorinostat after the initial 12-week period for a total of 36 weeks. Patient 3, was enrolled into this modification of the study and demonstrated significant clinical and laboratory improvement as assessed by CDAI. However, in this case this was not associated with improvement in intestinal mucosal inflammation nor increase in FoxP3 T cells. Neither of the two treated patients experienced adverse effects as a result of Vorinostat administration. Patient three who had failed previous biologic treatment was placed on ustekinumab treatment and then experienced a rapid improvement in mucosal healing. Thus, vorinostat treatment has shown safety and may be an effective treatment for Crohn’s disease. With respect to our studies of CVID during this period we have continued on-going clinical and immunologic assessment of a subset of CVID patients who develop nodular regenerative hyperplasia (NRH), a previously recognized, but poorly described liver complication of CVID that was thought in prior studies to be benign in nature. Our analysis of NRH patients in the CVID patient population revealed that these patients developed severe and in many cases progressive disease resulting in hepatic dysfunction or failure. Thus, contrary to prior reports that NRH is a benign non-fibrotic non-cirrhotic disease, NRH appears to be a severe and in some cases fatal manifestation of CVID. Detailed clinical and pathologic analysis allowed us to discern that patients may present with mild increases in liver transaminase enzymes and alkaline phosphatase levels. However, patients’ clinical status may progress with evidence of significant portal hypertension associated with reverse hepatic flow resulting in splenomegaly with cellular sequestration (thrombocytopenia and neutropenia), hallmarks of disease progression. Finally, patients’ disease progression may include liver histology characterized by an autoimmune hepatitis-like picture superimposed on the NRH; these patients frequently develop rapidly progressive hepatic failure. Immunologic evaluation of patients demonstrated that NRH was associated with infiltration of CD8+ T cells producing increased amounts of IFN-g to an extent that correlates with disease severity. Implementation of immunosuppression therapy directed against this T cell immune-mediated process may halt disease progression but only when implemented early in the disease process. Furthermore, in CVID patients with NRH who undergo liver transplantation may have reoccurrence of the disease within the transplanted liver. These facts indicate that NRH in CVID is an immune-mediated process that not secondary to a vascular insult as may be the case in other cases of NRH not associated with CVID. This view is confirmed by our experience with one patient whose NRH was alleviated by successful bone marrow transplantation to cure CVID. In studies of XLA we sought to determine the immunologic basis of the increased occurrence of Crohn's disease in patients with XLA. In these studies we determined the immunologic status of three XLA patients with clinical histories and histologic evidence of small bowel (ileal) and right sided large intestinal Crohn’s disease. These patients have all failed treatment with standard of care immunosuppressive agents, including anti TNF-alpha, anti-integrin (vedolizumab) and steroid therapy. In two of these patients an increased IL-1beta level was observed in peripheral blood mononuclear cells upon stimulation with LPS and nigericin, known NLRP3 inflammasome activating agents. In addition, these patients exhibited increased IL-18 and IFN-gamma in fixed intestinal tissue upon RNAscope evaluation. These data suggested that two of the patients may have active Crohn’s disease due to increased NLRP3 inflammasome activation; these two were therefore placed on anakinra administration in order to block the effects of IL-1beta generation. This treatment led to a significant decreased abdominal pain and occurrence of watery stools; however, significant intestinal inflammation persisted t the histologic level. This was thought to be due to inflammasome IL-18 production leading to the aforementioned Th1 T cell production of IFN-gamma. In the absence of commercial inhibitors of IL-18, patients were placed on an anti-IL-12p40 mAB (Ustekinumab) inasmuch as IL-12 has been shown to be necessary for IL-18R expression. The addition of Ustekinumab to the treatment regimen led to amelioration of mucosal inflammation in one patient and improvement in the other.