Search PubMed⌕ Search

Biomedical subjects

M C Sneller

Publications and source records attributed to M C Sneller.

At least 19 recordsLinked to original sources
PubMed2005

Orbital socket contracture: a complication of inflammatory orbital disease in patients with Wegener's granulomatosis.

AIM: To describe the clinical characteristics of orbital socket contracture in patients with Wegener's granulomatosis (WG). METHODS: A retrospective cohort study The medical records of 256 patients with WG examined at the National Institutes of Health from 1967 to 2004 were reviewed to identify patients with orbital socket contracture. Details of the orbital disease including Hertel exophthalmometry readings, radiological findings, and results of eye examinations were recorded. Orbital socket contracture was defined as orbital inflammation with proptosis followed by the development of enophthalmos and radiographic evidence of residual fibrotic changes in the orbit. To examine for risk factors in the development of a contracted orbit, patients with orbital socket contracture were compared to patients without contracture with respect to multiple variables including history of orbital surgery, orbital disease severity, and major organ system involvement. The main outcome measures were the clinical characteristics of orbital socket contracture associated with inflammatory orbital disease in patients with WG. RESULTS: Inflammatory orbital disease occurred in 34 of 256 (13%) patients and detailed clinical data on 18 patients were available and examined. Orbital socket contracture occurred during the clinical course in six patients; the features included restrictive ophthalmopathy (five), chronic orbital pain (three), and ischaemic optic nerve disease (two) resulting in blindness (no light perception) in one patient. The orbital socket contracture occurred within 3 months of treatment with immunosuppressive medications for inflammatory orbital disease in five patients and was not responsive to immunosuppressive medications. The median degree of enophthalmos in the contracted orbit compared with the fellow eye was 2.8 mm (range 1.5-3.5 mm) by Hertel exophthalmometry. There were no risk factors that predicted development of orbital socket contracture. CONCLUSIONS: In six patients with WG and active inflammatory orbital disease, orbital socket contracture occurred during the treatment course with systemic immunosuppressive medications. The orbital socket contracture, presumably caused by orbital fibrosis, led to enophthalmos, restrictive ophthalmopathy, chronic orbital pain, and optic nerve disease and was not responsive to immunosuppressive therapy. Orbital socket contracture has not been previously reported as a complication of inflammatory orbital disease associated with WG and was an important cause of visual morbidity in our cohort of patients.

Adolescent↗
PubMed2004

Expression of chemokine and inhibitory receptors on natural killer cells: effect of immune activation and HIV viremia.

We examined the cell-surface expression of chemokine and natural killer (NK) cell inhibitory receptors (iNKRs) on NK cells from individuals with human immunodeficiency virus (HIV) infection, chronic hepatitis C infection, and Wegener's granulomatosis (WG), an inflammatory, granulomatous vasculitis. The expression of CCR5 on NK cells was up-regulated in individuals with HIV viremia and in individuals with active WG, indicating that expression of this receptor is modulated by states of immune activation associated with viral infection and inflammatory or immune-mediated diseases. In contrast, iNKRs were shown to be up-regulated only on NK cells of individuals with HIV viremia, and they returned to a normal level when viremia was controlled with effective antiviral therapy. In individuals with HIV-1 viremia, there was a direct correlation between the level of expression of p58.1, p58.2, and CD94 receptors and plasma HIV viremia, suggesting that ongoing active HIV replication has an effect on the expression of such receptors on NK cells. These results suggest that immune activation leads to abnormal cell-surface expression of chemokine receptors on NK cells, whereas HIV-specific processes account for the up-regulation of iNKRs on NK cells; this may explain the NK cell-functional defects seen in HIV infection.

Antiretroviral Therapy, Highly Active↗
PubMed2001

The development of lymphomas in families with autoimmune lymphoproliferative syndrome with germline Fas mutations and defective lymphocyte apoptosis.

Lymphomas were studied in kindreds with autoimmune lymphoproliferative syndrome (ALPS; Canale-Smith syndrome), a disorder of lymphocyte homeostasis usually associated with germline Fas mutations. Fas (CD95/APO-1) is a cell surface receptor that initiates programmed cell death, or apoptosis, of activated lymphocytes. Lymphoma phenotype was determined by immunohistochemistry, frequency of CD3(+)CD4(-)CD8(-) T-cell-receptor alpha/beta cells by flow cytometry, nucleotide sequences of the gene encoding Fas (APT1, TNFRSF6), and the percentage of lymphocytes undergoing apoptosis in vitro. Of 223 members of 39 families, 130 individuals possessed heterozygous germline Fas mutations. Eleven B-cell and T-cell lymphomas of diverse types developed in 10 individuals with mutations in 8 families, up to 48 years after lymphoproliferation was first documented. Their risk of non-Hodgkin and Hodgkin lymphomas, respectively, was 14 and 51 times greater than expected (each P <.001). Investigation of these 10 patients and their relatives with Fas mutations revealed that all had defective lymphocyte apoptosis and most had other features of ALPS. The tumor cells retained the heterozygous Fas mutations found in the peripheral blood and manifested defective Fas-mediated killing. These data implicate a role for Fas-mediated apoptosis in preventing B-cell and T-cell lymphomas. Inherited defects in receptor-mediated lymphocyte apoptosis represent a newly appreciated risk factor for lymphomas.

Adult↗
PubMed2001

Increases in circulating and lymphoid tissue interleukin-10 in autoimmune lymphoproliferative syndrome are associated with disease expression.

Autoimmune lymphoproliferative syndrome (ALPS) is an inherited disorder in which genetic defects in proteins that mediate lymphocyte apoptosis, most often Fas, are associated with enlargement of lymph nodes and the spleen and a variety of autoimmune manifestations. Some patients with ALPS have relatives with these same apoptotic defects, however, who are clinically well. This study showed that the circulating levels of interleukin 10 (IL-10) were significantly higher (P <.001) in 21 patients with ALPS than in healthy controls. Moreover, the peripheral blood mononuclear cells (PBMCs) and lymphoid tissues of these patients with ALPS contained significantly higher levels of IL-10 messenger RNA (mRNA; P <.001 and P <.01, respectively). By fractionating PBMC populations, disproportionately high concentrations of IL-10 mRNA were found in the CD4(-)CD8(-) T-cell population, expansion of which is virtually pathognomonic for ALPS. Immunohistochemical staining showed intense IL-10 protein signals in lymph node regions known to contain CD4(-)CD8(-) T cells. Nonetheless, in vitro studies showed no influence of IL-10 on the survival of CD4(-)CD8(-) T cells. Overexpression of IL-10 in patients with inherited apoptotic defects is strongly associated with the overt manifestations of ALPS.

Apoptosis↗
PubMed2001

Common variable immunodeficiency.

Common variable immunodeficiency (CVI) is a heterogeneous immunodeficiency syndrome characterized by hypogammaglobulinemia, recurrent bacterial infections, and a variety of immunological abnormalities. In addition to recurrent infections, patients with this syndrome also suffer from an increased incidence of autoimmune disease and malignancy. Because the spectrum of associated diseases is broad, patients with CVI are seen by a variety of medical specialists. In this review, the pathogenesis, clinical manifestations, diagnosis, and treatment of CVI are discussed.

Autoimmunity↗
PubMed2001

Infections in patients with immunodeficiency with thymoma (Good syndrome). Report of 5 cases and review of the literature.

Immunodeficiency with thymoma (Good syndrome, GS) is a rare, adult-onset condition that is characterized by thymoma, hypogammaglobulinemia, and low numbers of peripheral B cells. CD4+ T lymphopenia and an inverted CD4:CD8+ T-cell ratio may be present. Here we report 5 patients with GS and infectious complications who were seen at 3 institutions between 1983 and 1999. Three patients had recurrent sinopulmonary infections, 3 had severe cytomegalovirus (CMV) disease, and 1 had Pneumocystis carinii pneumonia. Review of the literature identified 46 other reports of infections in GS patients. The infections reported in all 51 patients included recurrent sinopulmonary infection (19 cases with documented respiratory pathogens), generally with encapsulated bacteria, most often Haemophilus influenzae (11 cases); CMV disease (5 cases); bacteremia (7 cases); oral or esophageal candidiasis (6 cases); persistent mucocutaneous candidiasis (5 cases); chronic diarrhea (5 cases with documented stool pathogens); urinary tract infections (4 cases); P. carinii pneumonia (3 cases); tuberculosis (2 cases); Kaposi sarcoma (1 case); disseminated varicella (1 case); candidemia (1 case); wound infection with Clostridium perfringens (1 case); Mycoplasma arthritis (1 case); and other infections. Patients with GS present with a spectrum of sinopulmonary infections and pathogens similar to common variable immunodeficiency (CVID). Compared with patients with CVID, opportunistic infections, including severe CMV disease, P. carinii pneumonia, and mucocutaneous candidiasis, appear to be more common in patients with GS, and patients with GS may have a worse prognosis. GS should be ruled out in patients with thymoma or CVID who develop severe, especially opportunistic, infections. Treatment with intravenous immune globulin is recommended for all patients with GS.

Agammaglobulinemia↗
PubMed2000

Report of a factor VIII inhibitor in a patient with autoimmune lymphoproliferative syndrome.

The occurrence of factor VIII inhibitors in non-hemophilic patients is a rare event with a potentially lethal outcome. Despite its infrequent occurrence, the association of this inhibitor with multiple autoimmune diseases is well recognized. We report the case of a patient with the recently described autoimmune lymphoproliferative syndrome (ALPS) who developed an inhibitor to factor VIII. ALPS is a disease characterized by defective lymphocyte apoptosis due to inherited mutations in genes that regulate apoptosis, with the resulting enlargement of lymphoid organs and a variety of autoimmune manifestations. Published 2000 Wiley-Liss, Inc.

Autoimmune Diseases↗
PubMed2000

Use of methotrexate and glucocorticoids in the treatment of Wegener's granulomatosis. Long-term renal outcome in patients with glomerulonephritis.

OBJECTIVE: To determine the long-term renal outcome in patients with Wegener's granulomatosis (WG) and active glomerulonephritis who were treated with methotrexate (MTX) and glucocorticoids. METHODS: An open-label, prospective standardized trial using weekly low-dose MTX and glucocorticoids for the treatment of WG was performed. Forty-two patients were enrolled into the study, of whom 21 had active glomerulonephritis as a disease manifestation. The mean pretreatment level of serum creatinine in the patients with glomerulonephritis was 1.4 mg/dl. The extent of renal function in these patients at the time of their last followup was subsequently examined. RESULTS: Overall, 20 of 21 patients achieved renal remission. At 1 month and 6 months following study entry, the serum creatinine level in all patients either remained stable or improved. The 20 patients have now been followed up for a median time of 76 months (range 20-108 months). Only 2 patients have had a rise of >0.2 mg/dl in their creatinine level from the time of enrollment to the most recent followup examination. Of the remaining 18 patients, 12 have had stable renal function and 6 have had improvement in their creatinine levels by more than 0.2 mg/dl. CONCLUSION: In this study, the use of MTX and prednisone as initial therapy for patients with WG-related glomerulonephritis and a normal or near-normal level of serum creatinine was not associated with a long-term decline in renal function.

Adult↗
PubMed1999

A staged approach to the treatment of Wegener's granulomatosis: induction of remission with glucocorticoids and daily cyclophosphamide switching to methotrexate for remission maintenance.

OBJECTIVE: To determine the efficacy of a daily cyclophosphamide (CYC) and glucocorticoid induction and methotrexate (MTX) remission-maintenance regimen for the treatment of Wegener's granulomatosis (WG). METHODS: An open-label, prospective, standardized trial for the treatment of WG was performed using CYC and glucocorticoids for remission induction and MTX for remission maintenance. Thirty-one patients were enrolled in this study. Outcome was assessed using predetermined definitions based on clinical characteristics and pathologic, laboratory, and radiographic findings. RESULTS: The use of CYC and glucocorticoids for remission induction and MTX for remission maintenance resulted in disease remission for all 31 patients. The median time to remission was 3 months and the median time to discontinuation of glucocorticoids was 8 months. No patients have died, and 5 patients (16%) have had disease relapses at a median of 13 months after achieving remission. Only 2 patients (6%) have had to withdraw from the trial as a result of medication toxicity. CONCLUSION: The use of CYC and glucocorticoids for remission induction and MTX for remission maintenance was shown by this study to be an acceptable alternative therapy for patients with active WG, including those with severe disease at onset.

Adolescent↗
PubMed1999

Regulation of immunoglobulin production in hyper-IgE (Job's) syndrome.

BACKGROUND: The hyper-IgE (HIE), or Job's, syndrome is a rare, complex disorder characterized by high levels of serum IgE in childhood and chronic dermatitis with recurrent, often severe sinopulmonary and skin infections. Although the etiology of HIE syndrome is unknown, there is evidence that patients with HIE have abnormalities in cellular immune responses, as well as in the production of polyclonal and antigen-specific antibodies. Furthermore, there appears to be a common (but still undefined) mechanism underlying the regulation of IgE and IgG4 in this condition. OBJECTIVE: We sought to assess the role of cytokines or cytokine receptor blockade in regulating IgE and IgG4 production in HIE. METHODS: PBMCs were isolated from patients with HIE (n = 9) and normal individuals (n = 8), and IgE and IgG4 production was assessed spontaneously, in the presence of recombinant IL-4, IL-13, IL-6, IL-8, IL-12, and IFN-gamma, under conditions in which the IL-4R was blocked or when these cytokines were neutralized by specific monoclonal or polyclonal antibodies. RESULTS: In PBMCs from patients with HIE, a significant (P <.01) reduction in the spontaneously produced IgE (and IgG4) was induced by either IFN-gamma or IL-12, although neither cytokine could totally abrogate the immunoglobulin production. Whereas spontaneous IgE (and IgG4) production was not affected by exogenous IL-4 and IL-13, neutralizing antibodies to IL-4 and IL-13 also significantly (P <.01) reduced the production of IgE and IgG4, a finding supported by the observation of increased expression of IgE germline transcripts in these patients. In contrast to the neutralization of IL-4 and IL-13 protein, anti-IL-4R antibodies or soluble IL-4R completely suppressed IgE and IgG4 production in HIE. Similarly, IL-8 or antibodies to IL-6 and TNF-alpha, cytokines known to affect IL-4-dependent IgE production, completely inhibited both IgE and IgG4 production. CONCLUSION: These data show that overproduction of IgE and IgG4 can be regulated by a number of cytokines affecting the IL-4-dependent pathway of IgE/IgG4 production in HIE and suggest new targets for therapeutic intervention.

Cytokines↗
PubMed1999

Autoimmune lymphoproliferative syndrome with defective Fas: genotype influences penetrance.

Autoimmune lymphoproliferative syndrome (ALPS) is a disorder of lymphocyte homeostasis and immunological tolerance. Most patients have a heterozygous mutation in the APT1 gene, which encodes Fas (CD95, APO-1), mediator of an apoptotic pathway crucial to lymphocyte homeostasis. Of 17 unique APT1 mutations in unrelated ALPS probands, 12 (71%) occurred in exons 7-9, which encode the intracellular portion of Fas. In vitro, activated lymphocytes from all 17 patients showed apoptotic defects when exposed to an anti-Fas agonist monoclonal antibody. Similar defects were found in a Fas-negative cell line transfected with cDNAs bearing each of the mutations. In cotransfection experiments, Fas constructs with either intra- or extracellular mutations caused dominant inhibition of apoptosis mediated by wild-type Fas. Two missense Fas variants, not restricted to patients with ALPS, were identified. Variant A(-1)T at the Fas signal-sequence cleavage site, which mediates apoptosis less well than wild-type Fas and is partially inhibitory, was present in 13% of African American alleles. Among the ALPS-associated Fas mutants, dominant inhibition of apoptosis was much more pronounced in mutants affecting the intracellular, versus extracellular, portion of the Fas receptor. Mutations causing disruption of the intracellular Fas death domain also showed a higher penetrance of ALPS phenotype features in mutation-bearing relatives. Significant ALPS-related morbidity occurred in 44% of relatives with intracellular mutations, versus 0% of relatives with extracellular mutations. Thus, the location of mutations within APT1 strongly influences the development and the severity of ALPS.

Alleles↗
PubMed1999

Autoimmune lymphoproliferative syndrome: a syndrome associated with inherited genetic defects that impair lymphocytic apoptosis--CT and US features.

PURPOSE: To describe the imaging findings in patients with autoimmune lymphoproliferative syndrome (ALPS) and to relate the findings to the clinical and genetic features of this recently recognized syndrome. MATERIALS AND METHODS: Retrospective or prospective reviews of the computed tomographic (CT) and ultrasonographic (US) studies and the clinical features in 19 consecutive patients with ALPS were performed. RESULTS: Most patients presented in the 1st year of life with symptoms of adenopathy and hepatosplenomegaly. At the time of presentation to the institution, 12 patients had already undergone splenectomy, and 14 patients had developed autoimmune disorders. All patients had multifocal adenopathy, which was massive in some patients; 14 of 15 patients who underwent CT of the chest had an enlarged thymus, and all six patients who retained their spleens and who underwent imaging had splenomegaly. Ten of 18 patients who underwent liver imaging had hepatomegaly. The adenopathy at US was hyper- and/or isoechoic relative to the liver and thyroid and was enhanced at CT in some patients. All patients had defective lymphocytic apoptosis, or programmed cell death, which was due to specific Fas (APT1 [TNFRSF6]) mutations in 15 patients. CONCLUSION: Patients with ALPS demonstrate nonspecific but often dramatic imaging findings of lymphoproliferative disorders, such as adenopathy, splenomegaly, thymic enlargement, and hepatomegaly. The stability of the clinical findings over months to years and the pattern of lymph node echogenicity may suggest the diagnosis of ALPS.

Adolescent↗
PubMed1999

Pituitary involvement by Wegener's granulomatosis: a report of two cases.

We describe two cases of pituitary involvement by Wegener's granulomatosis. At initial presentation, or during subsequent disease "flares," a pattern of pituitary abnormality was suggested. During periods of remission, we found the pituitary returned to a nearly normal appearance. Loss of the normal posterior pituitary T1 hyper-intensity matched a clinical persistence of diabetes insipidus, suggesting there is permanent damage to this structure by the initial disease process.

Adolescent↗
PubMed1998

Use of cytotoxic agents and cyclosporine in the treatment of autoimmune disease. Part 2: Inflammatory bowel disease, systemic vasculitis, and therapeutic toxicity.

When cytotoxic agents were introduced, their ability to disrupt nucleic acid and protein synthesis led to their effective use for the treatment of neoplastic disease. During the course of this use, however, it became apparent that these agents also suppress the immune system. This usually unwelcome effect was subsequently studied and beneficially directed toward the treatment of non-neoplastic diseases in which autoimmune mechanisms were considered important to pathogenesis. As a result of these investigations, cytotoxic agents and, more recently, cyclosporine have emerged to become an important part of the therapeutic regimen for many autoimmune diseases. Nonetheless, these medications may still cause treatment-induced illness or even death. It is therefore particularly important to weigh the benefits and risks of cytotoxic therapy when treating a non-neoplastic disease. This two-part Clinical Staff Conference reviews data on the efficacy and toxicity of cytotoxic drugs and cyclosporine in selected autoimmune diseases. In part 2, we focus on the role of these agents in treating inflammatory bowel disease and systemic vasculitis and review the toxic effects of these agents.

Cyclosporine↗
PubMed1998

Use of cytotoxic agents and cyclosporine in the treatment of autoimmune disease. Part 1: rheumatologic and renal diseases.

When cytotoxic agents were initially introduced, their ability to disrupt nucleic acid and protein synthesis led to their effective use for the treatment of neoplastic disease. During the course of this use, however, it became apparent that these agents also suppress the immune system. This usually unwelcome effect was subsequently studied and beneficially directed toward the treatment of non-neoplastic diseases in which autoimmune mechanisms were considered important to pathogenesis. As a result of these investigations, cytotoxic agents and, more recently, cyclosporine have emerged to become an important part of the therapeutic regimen for many autoimmune diseases. Nonetheless, these medications may still cause treatment-induced illness or even death. It is therefore particularly important to weigh the benefits and risks of cytotoxic therapy when treating a non-neoplastic disease. This two-part Clinical Staff Conference reviews data on the efficacy and toxicity of cytotoxic drugs and cyclosporine in selected autoimmune diseases. Part 1 examines the manner in which these agents have been used to treat rheumatologic and renal diseases.

Autoimmune Diseases↗
PubMed1998

Active Wegener's granulomatosis is associated with HLA-DR+ CD4+ T cells exhibiting an unbalanced Th1-type T cell cytokine pattern: reversal with IL-10.

Wegener's granulomatosis (WG) is a granulomatous vasculitis that affects the upper respiratory tract, lung, and kidney. Since T cells make up a significant proportion of cells infiltrating granulomatous lesions in WG, we investigated the proliferative response and cytokine profile of T cells from these patients. PBMCs were isolated from 12 patients with active WG, 7 patients with inactive disease, and 12 healthy normal donors. PBMCs from clinically active WG patients exhibited increased proliferation following stimulation with either PMA/ionomycin or anti-CD2 and anti-CD28, when compared with normal donors. In addition, these PBMCs exhibited increased secretion of IFN-gamma, but not of IL-4, IL-5, or IL-10. Furthermore, TNF-alpha production from PBMCs and CD4+ T cells isolated from patients with WG was elevated, when compared with healthy donors. In further studies, we investigated the ability of WG patients' monocytes to produce IL-12 and showed that both inactive and active patients produced increased amounts of IL-12. Finally, the in vitro IFN-gamma production by WG PBMC is inhibited in a dose-dependent manner by exogenous IL-10. These data suggest that T cells from WG patients overproduce IFN-gamma and TNF-alpha, probably due to dysregulated IL-12 secretion, and that IL-10 may therefore have therapeutic implications for this disease.

Adult↗