Dhanpat Jain

Liver Disease in Patients with Hereditary Hemorrhagic Telangiectasia

BACKGROUND Hereditary hemorrhagic telangiectasia, or Rendu-Osler-Weber disease, is an autosomal dominant disorder characterized by angiodysplastic lesions (telangiectases and arteriovenous malformations) that affect many organs. Liver involvement in patients with this disease has not been fully characterized. METHODS We studied the clinical findings and results of hemodynamic, angiographic, and imaging studies in 19 patients with hereditary hemorrhagic telangiectasia and symptomatic liver involvement. RESULTS We evaluated 14 women and 5 men who ranged in age from 34 to 74 years. All but one of the patients had a hyperdynamic circulation (cardiac index, 4.2 to 7.3 liters per minute per square meter of body-surface area). In eight patients, the clinical findings were consistent with the presence of high-output heart failure. The cardiac index and pulmonary-capillary wedge pressure were elevated in the six patients in whom these measurements were performed. After a median period of 24 months, the condition of three of the eight patients had improved, four were in stable condition with medical therapy, and one had died. Six patients had manifestations of portal hypertension such as ascites or variceal bleeding. The hepatic sinusoidal pressure was elevated in the four patients in whom it was measured. After a median period of 19 months, the condition of two of the six patients had improved, and the other four had died. Five patients had manifestations of biliary disease, such as an elevated alkaline phosphatase level and abnormalities on bile duct imaging. After a median period of 30 months, the condition of two of the five had improved, the condition of one was unchanged, heart failure had developed in one, and one had died after an unsuccessful attempt at liver transplantation. CONCLUSIONS In patients with hereditary hemorrhagic telangiectasia and symptomatic liver-involvement, the typical clinical presentations include high-output heart failure, portal hypertension, and biliary disease.

Donor APCs are required for maximal GVHD but not for GVL.

Graft-versus-host disease (GVHD) is a major source of morbidity in allogenic stem cell transplantation. We previously showed that recipient antigen-presenting cells (APCs) are required for CD8-dependent GVHD in a mouse model across only minor histocompatibility antigens (minor H antigens). However, these studies did not address the function of donor-derived APCs after GVHD is initiated. Here we show that GVHD develops in recipients of donor major histocompatibility complex class I–deficient (MHC I−) bone marrow. Thus, after initial priming, CD8 cells caused GVHD without a further requirement for hematopoietic APCs, indicating that host APCs are necessary and sufficient for GHVD. Nonetheless, GVHD was less severe in recipients of MHC I− bone marrow. Therefore, once initiated, GVHD is intensified by donor-derived cells, most probably donor APCs cross-priming alloreactive CD8 cells. Nevertheless, donor APCs were not required for CD8-mediated graft-versus-leukemia (GVL) against a mouse model of chronic-phase chronic myelogenous leukemia. These studies identify donor APCs as a new target for treating GVHD, which may preserve GVL.

Target Antigens Determine Graft-versus-Host Disease Phenotype

Chronic graft-vs-host disease (cGVHD) is an increasingly frequent complication of allogeneic stem cell transplantation. Phenotypically, cGVHD differs from patient to patient; in particular, a subset of patients develops extensive cutaneous fibrosis. Similarly, graft-vs-host disease (GVHD) is distinct in inbred murine donor:recipient pairings, indicating a genetic component to disease phenotype. The B10.D2 → BALB/c (H-2d) strain pairing uniquely recapitulates key pathologic features of fibrotic human cutaneous cGVHD. To distinguish whether this genetic component is due to differences in genes that modulate immune responses or to the specific Ags targeted, we asked whether skin-dominant cGVHD also develops in the B10 → BALB.B (H-2b) and B10.BR → BALB.K (H-2k) MHC-congenic pairings. Because each MHC haplotype presents different peptides and selects different T cell repertoires, GVHD in each donor:recipient pair undoubtedly targets different Ags. We found that, in contrast to BALB/c recipients, BALB.B mice never manifested skin disease while BALB.K mice developed a modified form of skin disease. Instead, BALB.B and BALB.K recipients developed systemic GVHD which was absent in BALB/c mice. Moreover, in (B10 × B10.D2)F1 → (BALB.B × BALB/c)F1 H-2b/d transplants, recipients developed both cutaneous and systemic disease. Thus, the selection of immunodominant Ags determines the target and character of GVHD, providing insight into the genetic basis for different forms of GVHD.

Glucocerebrosidase gene-deficient mouse recapitulates Gaucher disease displaying cellular and molecular dysregulation beyond the macrophage

In nonneuronopathic type 1 Gaucher disease (GD1), mutations in the glucocerebrosidase gene (GBA1) gene result in glucocerebrosidase deficiency and the accumulation of its substrate, glucocerebroside (GL-1), in the lysosomes of mononuclear phagocytes. This prevailing macrophage-centric view, however, does not explain emerging aspects of the disease, including malignancy, autoimmune disease, Parkinson disease, and osteoporosis. We conditionally deleted the GBA1 gene in hematopoietic and mesenchymal cell lineages using an Mx1 promoter. Although this mouse fully recapitulated human GD1, cytokine measurements, microarray analysis, and cellular immunophenotyping together revealed widespread dysfunction not only of macrophages, but also of thymic T cells, dendritic cells, and osteoblasts. The severe osteoporosis was caused by a defect in osteoblastic bone formation arising from an inhibitory effect of the accumulated lipids LysoGL-1 and GL-1 on protein kinase C. This study provides direct evidence for the involvement in GD1 of multiple cell lineages, suggesting that cells other than macrophages may be worthwhile therapeutic targets.

Clinicopathologic features and survival in fibrolamellar carcinoma: comparison with conventional hepatocellular carcinoma with and without cirrhosis.

Fibrolamellar carcinoma arises in noncirrhotic livers of young individuals and has been considered to be less aggressive than conventional hepatocellular carcinoma. This study compares survival and clinicopathologic features of fibrolamellar carcinoma with hepatocellular carcinoma arising in noncirrhotic and cirrhotic livers. Clinical and pathologic features including age, gender, tumor size, stage and survival were recorded in 20 resected cases of fibrolamellar carcinoma. Survival was compared with resected hepatocellular carcinoma without (n=32) and with cirrhosis (n=30). Proliferative activity was determined by immunohistochemistry for Ki-67. In all, 12 (60%) patients with fibrolamellar carcinoma died during follow-up; the 5-year survival was 45%. Mortality in fibrolamellar carcinoma was higher with metastatic disease at presentation (6/7, 86% vs 5/13, 39%, P=0.06). Age, gender and tumor size did not correlate with survival. The 5-year (45 vs 56%, P=0.4) as well as overall survival (40 vs 56.3%, P=0.3) was similar in fibrolamellar carcinoma and hepatocellular carcinoma without cirrhosis. The 5-year and overall survival in hepatocellular carcinoma with cirrhosis was 27 and 23.3%, respectively, which was not significantly different compared to fibrolamellar carcinoma (P=0.2). Among the cases without metastases at presentation, 5-year survival in fibrolamellar carcinoma (62%) and hepatocellular carcinoma without cirrhosis (57%) was significantly better (P=0.03) than hepatocellular carcinoma with cirrhosis (27%). The mean Ki-67 index was similar in all three groups (P=0.1). In conclusion, fibrolamellar carcinoma is an aggressive neoplasm with 45% 5-year survival and overall mortality of 60%. Nearly half the patients develop lymph node or distant metastasis. The prognosis of fibrolamellar carcinoma is similar to conventional hepatocellular carcinoma. Among nonmetastatic cases, the prognosis is better in fibrolamellar carcinoma and hepatocellular carcinoma without cirrhosis compared to hepatocellular carcinoma with cirrhosis. The better outcome in fibrolamellar carcinoma appears to be due to the absence of cirrhosis rather than its distinct clinicopathologic features.

Spectrum of histologic changes in colonic biopsies in patients treated with mycophenolate mofetil

Mycophenolate mofetil, an immunosuppressive agent, is frequently used following bone marrow and solid organ transplantation. Diarrhea is a commonly seen side effect of mycophenolate mofetil, which may necessitate colonic biopsy in some patients. The histologic changes found in this setting have been reported to mimic self-limited colitis, graft-vs-host disease or inflammatory bowel disease in isolated case reports, and could pose diagnostic and management difficulties. The goal of this study is to define the spectrum of histologic changes in colonic biopsies associated with mycophenolate mofetil usage. All solid organ transplant patients who received mycophenolate mofetil and underwent colonic biopsy for gastrointestinal symptoms from 1999 to 2007 were included in the study. Patients who did not receive mycophenolate mofetil were used as controls. Various histologic features including architectural distortion, apoptosis, inflammatory infiltrate, Paneth cell metaplasia and mucin depletion were subjectively evaluated and scored (scale: 0–3) by two independent reviewers in a blinded fashion. Forty solid organ transplant patients underwent colonic biopsy for gastrointestinal symptoms during the study period. Biopsies from 69% of patients on mycophenolate mofetil showed histologic changes. Apoptosis (41%) and architectural distortion (66%) were seen more frequently in patients receiving mycophenolate mofetil as compared to the control group (13%). The histologic changes in patients receiving mycophenolate mofetil were categorized as normal/near normal (31%), inflammatory bowel disease-like (28%), graft-vs-host disease-like (19%), ischemia-like (3%) and self-limited colitis-like (16%) changes. Of the controls, only one patient showed a graft-vs-host disease-like histologic pattern. In conclusion, histologic changes are frequently associated with mycophenolate mofetil use and can resemble self-limited colitis, graft-vs-host disease and inflammatory bowel disease leading to diagnostic difficulties. Increased awareness of the histologic spectrum of mycophenolate mofetil-induced changes is required by the pathologist to avoid diagnostic errors.

Evidence for the neoplastic transformation of Von-Meyenburg complexes

Von-Meyenburg complexes (VMC) are seen frequently in the liver and are largely considered to be innocuous, with only 11 cases reported in the literature of neoplastic transformation of VMCs. The authors report three cases of cholangiocarcinoma, each occurring in a background of fibrosis and nodularity that was reported initially as micronodular cirrhosis. Although the livers showed cirrhosis, the central veins were often preserved, and regenerative activity was patchy and focal. Histologic examination revealed many VMCs, and a gradual transition from VMCs to hyperplastic or adenomatous lesions and cholangiocarcinoma. The adenomatous lesions consisted of extensive replacement of the parenchyma by tumor-like nodules of ductular proliferations without obvious features of malignancy. All three patients were older than 60 years of age and had portal hypertension. Computed tomographic scans showed multiple, small renal cysts in one patient. Immunohistochemical staining showed positivity for epithelial membrane antigen, carcinoembryonic antigen, and keratins (AE1/AE3 and CAM5.2) in tumor cells, consistent with cholangiocarcinoma. The pattern of fibrosis and nodularity in these cases is not typical of either congenital hepatic fibrosis or usual cirrhosis. The authors propose that these patients represent another aspect in the spectrum of ductal plate malformations that may be modified by other factors such as alcohol, drugs, or infection. To their knowledge, neoplastic transformation of VMCs in the background of such changes has never been reported before.

Effects of donor T-cell trafficking and priming site on graft-versus-host disease induction by naive and memory phenotype CD4 T cells

Graft-versus-host disease (GVHD) remains a major cause of morbidity and mortality in allogeneic stem cell transplantation. Effector memory T cells (T(EM)) do not cause GVHD but engraft and mount immune responses, including graft-versus-tumor effects. One potential explanation for the inability of T(EM) to cause GVHD is that T(EM) lack CD62L and CCR7, which are instrumental in directing naive T cells (T(N)) to lymph nodes (LN) and Peyer patches (PP), putative sites of GVHD initiation. Thus T(EM) should be relatively excluded from LN and PP, possibly explaining their inability to cause GVHD. We tested this hypothesis using T cells deficient in CD62L or CCR7, transplant recipients lacking PNAd ligands for CD62L, and recipients without LN and PP or LN, PP, and spleen. Surprisingly, CD62L and CCR7 were not required for T(N)-mediated GVHD. Moreover, in multiple strain pairings, GVHD developed in recipients that lacked LN and PP. Mild GVHD could even be induced in mice lacking all major secondary lymphoid tissues (SLT). Conversely, enforced constitutive expression of CD62L on T(EM) did not endow them with the ability to cause GVHD. Taken together, these data argue against the hypothesis that T(EM) fail to induce GVHD because of inefficient trafficking to LN and PP.

Central Memory CD8+ T Cells Induce Graft-versus-Host Disease and Mediate Graft-versus-Leukemia

In allogeneic hemopoietic stem cell transplantation, mature donor αβ T cells in the allograft promote T cell reconstitution in the recipient and mediate the graft-vs-leukemia (GVL) effect. Unfortunately, donor T cells can attack nonmalignant host tissues and cause graft-vs-host disease (GVHD). It has previously been shown that effector memory T cells not primed to alloantigen do not cause GVHD yet transfer functional T cell memory and mediate GVL. Recently, central memory T cells (TCM) have also been reported to not cause GVHD. In contrast, in this study, we demonstrate that purified CD8+ TCM not specifically primed to alloantigens mediate GVHD in the MHC-mismatched C57BL/6 (B6)→BALB/c and the MHC-matched, multiple minor histocompatibility Ag-mismatched C3H.SW→B6 strain pairings. CD8+ TCM and naive T cells (TN) caused similar histological disease in liver, skin, and bowel. B6 CD8+ TCM and TN similarly expanded in BALB/c recipients, and the majority of their progeny produced IFN-γ upon restimulation. However, in both models, CD8+ TCM induced milder clinical GVHD than did CD8+ TN. Nonetheless, CD8+ TCM and TN were similarly potent mediators of GVL against a mouse model of chronic-phase chronic myelogenous leukemia. Thus, in contrast to what was previously thought, CD8+ TCM are capable of inducing GVHD and are substantially different from TEM but only subtly so from TN.

Biliary and Pancreatic Dysgenesis in Mice Harboring a Mutation in Pkhd1

Autosomal recessive polycystic kidney disease is a hereditary fibrocystic disease that involves the kidneys and the biliary tract. Mutations in the PKHD1 gene are responsible for typical forms of autosomal recessive polycystic kidney disease. We have generated a mouse model with targeted mutation of Pkhd1 by disrupting exon 4, resulting in a mutant transcript with deletion of 66 codons and expression at approximately 30% of wild-type levels. Pkhd1(del4/del4) mice develop intrahepatic bile duct proliferation with progressive cyst formation and associated periportal fibrosis. In addition, these mice exhibit extrahepatic manifestations, including pancreatic cysts, splenomegaly, and common bile duct dilation. The kidneys are unaffected both histologically and functionally. Fibrocystin is expressed in the apical membranes and cilia of bile ducts and distal nephron segments but is absent from the proximal tubule. This pattern is unchanged in orthologous models of autosomal dominant polycystic kidney disease due to mutation in Pkd1 or Pkd2. Mutant fibrocystin in Pkhd1(del4/del4) mice also retains this expression pattern. The hypomorphic Pkhd1(del4/del4) mouse model provides evidence that reduced functional levels of fibrocystin are sufficient for cystogenesis and fibrosis in the liver and pancreas, but not the kidney, and supports the hypothesis of species-dependent differences in susceptibility of tissues to Pkhd1 mutations.