Autoantibodies during alpha-interferon therapy for chronic hepatitis B

The development of autoantibodies and autoimmune reactions has been reported during and after interferon (IFN) therapy. Thirteen different antibodies from the sera of 32 patients with chronic hepatitis B treated with alpha-interferon (alpha-IFN) were tested. Seventeen HBeAg-positive patients received 4.5 megaunits (MU) of recombinant IFN thrice weekly for 4 months, and 15 anti-HBe and HBV-DNA positive patients were treated with 5 MU/m2 of lymphoblastoid IFN thrice weekly for 6 months. Five patients (15%) had antinuclear antibodies (ANA) and one patient (3%) had smooth muscle antibodies before treatment. ANA appeared during IFN treatment in five (18%) of 28 previously negative patients. With discontinuation of treatment, the titer of ANA fell to undetectable levels in all patients. In contrast, none of the patients developed antibodies to endocrine organs, such as thyroid microsomal, thyroglobulin, parietal cells, pancreatic islet cell, and adrenal cortex antibodies or autoantibodies specifically associated with autoimmune liver disease such as liver kidney microsomal antibodies and antimitochondrial antibodies. There was no correlation between autoantibody positivity before therapy or autoantibody occurrence during treatment and response to IFN therapy. None of the patients developed clinical signs of autoimmune disease. These results indicate that these regimens of recombinant and lymphoblastoid IFN therapy of chronic hepatitis B are associated with a low risk of clinically significant autoimmunity.     

Interferon (IFN) therapy (recombinant IFN-alpha-2C or recombinant IFN-gamma) in metastasized hypernephroma

Recombinant interferon-alpha-2C (rec. IFN alpha-2C) and recombinant interferon-gamma (IFN-gamma) was studied in 12 patients with metastasized renal cell carcinoma. 8 patients were treated with IFN-alpha-2C: 1 patient achieved a complete remission, 2 patients showed mixed responses, and 2 had stabilisation of their disease. In 3 patients progressive disease was observed. IFN-gamma was studied in 4 patients; 2 patients showed stable and 2 progressive disease. Side effects of IFN-alpha treatment included influenza-like symptoms, moderate hematological toxicity and neurological symptoms. During treatment with IFN-gamma similar side effects were observed, although fever generally was more pronounced. All symptoms ceased after dosis reduction or discontinuation of treatment.     

A cytogenetic and fluorescence in situ hybridization evaluation of interferon-alpha in the treatment of chronic myeloid leukemia

The effect of interferon-alpha (IFN) for chronic myeloid leukemia (CML) in the chronic phase (CP) was retrospectively evaluated in comparison with that of busulfan (BU) or hydroxyurea (HU) given alone. Among 107 patients diagnosed with CML between 1982 and 1997, 72 CP cases evaluable for long-term follow-up included 13 patients treated with BU alone, 18 with HU alone, and 41 with IFN-based therapy. Complete cytogenetic response (CCR) was achieved in 4/41 IFN cases (10%), and partial or minimal cytogenetic response occurred in 18/41 IFN cases (44%). In contrast, no cytogenetic response (NCR) was achieved in any BU or HU case. IFN treatment for 6 to 60 months was needed to achieve CCR. Overall survival curves revealed that the IFN group had significantly better survival than BU and HU groups (p=0.008 and 0.04, respectively). A significant correlation was found between karyotypic findings and fluorescence in situ hybridization (FISH) analyses in IFN-treated cases (r=0.739, p=0.0001). In some cases, however, the two methods showed discrepancy; BCR/ABL-positive cells represented only 20-75% of interphase bone marrow cells in NCR cases, although all metaphases examined were positive for the Philadelphia chromosome (Ph). A discrepancy was also seen in CCR cases; up to 22% of cells assessed were BCR/ABL-positive. These findings suggest that IFN is a useful therapy for CML in CP, and may have a suppressive effect on the CML clone even in NCR cases. The results also indicate that a combination of FISH and cytogenetic analyses may provide more detailed information for evaluating the efficacy of IFN than conventional cytogenetics alone.     

Factors associated with the antinuclear antibody (ANA) titer of systemic autoimmune rheumatic diseases in ANA-positive patients after treatment: a retrospective study

Antinuclear antibodies (ANAs) are a serological hallmark of systemic autoimmune rheumatic diseases (SARDs); however, few studies have investigated their post-treatment levels. The mechanism by which ANA titers are upregulated in SARDs remains unclear. We assessed factors associated with the ANA titer after treatment. In this retrospective study, we analyzed the clinical database of Zhongshan Hospital, Medical College of Xiamen. Demographic data and baseline and 12-month post-treatment ANA titers were collected. Bivariate and multivariate analyses were performed to determine the factors associated with the ANA titer. This study identified 31,923 patients who underwent ANA assay for SARDs screening, and a total of 1043 patients were included in the study. Approximately 16% of the patients showed a decrease in the serological ANA titer. Younger patients (<?20) were 3?×?more likely to experience such a decrease (P?=?0.005) compared to older patients (≥?60 years). Having a baseline ANA titer?>?1:10,000 was associated with an increase likelihood of a decrease in the serological ANA titer compared with baseline ANA titer 1:10,000, 1:3200 and 1:1000 (P?<?0.001). We found that a decrease in the serum ANA titer at 12 months after treatment for SARDs is associated with age and ANA baseline titers.

     

Cancer immunotherapy using dendritic/tumour-fusion vaccine induces elevation of serum anti-nuclear antibody with better clinical responses

Dendritic cell (DC) vaccines might induce both anti-tumour immunity and autoimmunity. In this report, we demonstrate elevated levels of anti-nuclear antibody (ANA) in the sera of patients with cancer who had received immunotherapy with a dendritic/tumour-fusion vaccine. Twenty-two patients were treated with DC vaccine of fusion cells composed of autologous DCs and tumour cells (DC/tumour-fusion vaccine), which was generated by treating each cell type with polyethylene glycol. Nine of the 22 patients were treated with both the DC/tumour-fusion vaccine and systemic administration of recombinant human interleukin (rhIL)-12. Serum levels of ANA were examined with an enzyme-linked immunosorbent assay kit. One patient with gastric carcinoma (patient 1, DC/tumour-fusion vaccine alone), one patient with breast cancer (patient 2, DC/tumour-fusion vaccine alone) and one patient with ovarian cancer (patient 3, DC/tumour-fusion vaccine + rhIL-12) showed significant elevations of serum ANA levels during treatment. In patient 1 malignant ascitic effusion resolved and serum levels of tumour markers decreased. Patients 2 and 3 remained in good physical condition during treatment for 24 and 9 months, respectively. Immunoblot analysis indicated antibody responses to autologous tumour cells after vaccination in patient 2. None of the treated patients showed clinical symptoms suggesting autoimmune disease. Patients with elevated serum levels of ANA had significantly longer treatment periods than those without it. Elevated serum levels of ANA after DC/tumour-fusion cell vaccine might be associated with anti-tumour immune response induced by the vaccination.     

Failure of exogenously administered interferon-gamma or blockage of endogenous interleukin-4 with specific inhibitors to augment the incidence of autoimmune diabetes in male NOD mice.

Interferon (IFN)-gamma and interleukin (IL)-4 are prototypic type 1 and type 2 cytokines which are known to play pathogenetic and protective roles, respectively, in NOD mouse IDDM. The capacity of male NOD mice to produce more IL-4 and less IFN-gamma within the insulitic lesions than females has been suggested to contribute to their lower incidence of diabetes. In this study we have tested the effects of prolonged prophylactic treatment of male NOD mice with rat IFN-gamma, mouse IFN-gamma, anti-IL-4 monoclonal antibody (mAb) and recombinant murine soluble IL-4 receptor (smIL-4R) on the diabetogenic events leading to insulitis and diabetes. None of these treatments influenced spontaneous and/or cyclophosphamide-induced autoimmune diabetogenesis in male NOD mice. Control mice exhibited comparable histological signs of insulitis and incidence of diabetes to those treated with either mouse/rat IFN-gamma or specific IL-4 inhibitors. On the contrary, both clinical and histological signs of diabetes were suppressed by prophylactic treatment with anti-IFN-gamma mAb. These findings indicate that the autoimmune diathesis of male NOD mice towards IDDM cannot be augmented by manipulation of endogenous IFN-gamma or IL-4.     

Retroviral coexpression of IFN-alpha and IFN-gamma genes and inhibitory effects in chronic myeloid leukemia cells.

Interferon (IFN) is an effective treatment for chronic myeloid leukemia (CML) in chronic phases, and a number of in vitro antileukemic effects of IFN on CML cells have been reported. The transfer of cytokine genes into tumor cells is reportedly a valuable approach to improve the antitumor activity of cytokines in various models. We first investigated the possibility of transducing CML cells with the retroviral vectors LIalpha2SN and LIgammaSN, encoding the IFN-alpha2 and IFN-gamma genes, respectively, and with the bicistronic vector LIalpha2IrIgammaSN coexpressing the IFN-alpha2 and IFN-gamma genes. We then analyzed the effects of IFN-alpha2 and IFN-gamma produced alone or simultaneously on the proliferation of CML cells. We optimized the transduction efficiency by using the CML-derived K562 cell line. We then introduced IFN genes into CML CD34+ cells. Secretion of IFN-alpha and IFN-gamma was demonstrated in K562 and CML CD34+ cells transduced with the different vectors. The MHC class I antigens were overexpressed in both K562 and CML CD34+ transduced cells. Inhibition of the proliferation of LIalpha2IrIgammaSN-transduced CML cells was greater than with the LIalpha2SN and the LIgammaSN-transduced CML cells. We demonstrate an additive effect of IFN-alpha and IFN-gamma on the inhibition of K562 and CML CD34+ cell proliferation.     

Effect of granulocyte-macrophage colony-stimulating growth factor on interferon and tumor necrosis factor production in whole blood cell cultures of patients with acute myelogenous leukemia

The effect of recombinat human granulocyte-macrophage colony-stimulating growth factor (rHuGM-CSF) treatment on in vitro interferon (IFN) and tumor necrosis factor (TNF) production in peripheral blood cells of 46 patients with acute myelogenous leukemia (AML) was examined. GM-CSF significantly enhanced virus-induced IFN-alpha production in blood cells (containing 68% of blasts) of 28 patients with M4-M5 AML according to the French-American-British (FAB) classification and also phytohemagglutinin (PHA)-induced IFN-gamma production in blood cells (containing 70% of blasts) of 18 patients with AML MO-M3 type. In control blood cells (25 healthy persons) GM-CSF enhanced PHA-induced IFN-gamma but did not influence IFN-alpha production. In the presence of GM-CSF, TNF-alpha titers induced with lipopolysaccharide were also higher in control blood cells but not in cells of patients with M0-M3 or M4-M5 type of AML. The significance of GM-CSF-enhanced IFN-alpha and IFN-gamma production in antimicrobial and anti-leukemic immune reactions which can develop during GM-CSF therapy is discussed.     

Clinical evaluation of serum cytokine from patients with collagen diseases]

PURPOSE: Systemic autoimmune diseases such as systemic lupus erythematosus (SLE) and Sj?gren's syndrome (SS) are characterized by an imbalance of cytokine production. To clarify the relationship between the profile of cytokines and the pathophysiology of systemic autoimmune diseases, we estimated the cytokine levels in sera from patients with several systemic autoimmune diseases. METHOD: Serum cytokine levels in patients with unclassified connective tissue diseases were measured using ultrasensitive specific enzyme-linked immunosorbent assay (ELISA). RESULT: These patients were diagnosed using the established category by further examinations within a 2-year period. Sera from patients with SLE contained higher titers of IL-10, and equal levels of IFN gamma and TNF alpha compared with those of normal controls. Patients with progressive systemic sclerosis (PSS) showed lower titers of IL-10 and higher titers of IFN gamma and TNF alpha in their sera than those of healthy controls. Seronegative rheumatoid arthritis (snRA) patients had a higher amount of IL-10 and TNF alpha, equivalent level of IFN gamma in their sera compared to those of controls. Moreover, patients with Sj?gren's syndrome (SS) showed higher titers of IL-10 and TNF alpha, and an equivalent level of IFN gamma in their sera compared to healthy volunteers. CONCLUSION: Based on these findings, for the differential diagnosis of patients with systemic autoimmune diseases such as SLE, PSS, snRA and SS, it may be useful to measure the levels of cytokines such as IL-10, IFN gamma, and TNF alpha in their sera.     

C1q deposits at the dermoepidermal junction: A marker discriminating for discoid and systemic lupus erythematosus

Discoid lupus (DL) and systemic lupus erythematosus (SLE) patients have been comparatively evaluated for complement and immunoglobulin deposits at the dermoepidermal junction (DEJ) by immunofluorescence (IF). When IF was positive, C1q deposits were quasi-constantly found in SLE patients with or without skin lesions (90%), while C1q was found in only 29% of the DL patients. Of the 42 DL patients followed-up for at least 2 years, 4 have eventually evolved a systemic disease. In these 4, neither cryoglobulinemia nor significant titers of ANA had been found at the time of presentation. Only 1 of these 4 patients had initially circulating immune complexes (P.E.G.) and a positive IF in a normal sunprotected area. C1q deposits at the DEJ were present in all these 4. Of the remaining 38 DL patients, none has progressed to SLE: 8 had had significant titers of ANA, 5 had had circulating immune complexes, and 3 others had had cryoglobulinemia. Thus C1q deposits in DL cases are associated with a relatively high incidence of eventual systemic disease. Taken together, these data suggest that C1q deposits in skin may be a marker for systemic lupus.     

In vivo anti-nuclear antibodies in epithelial biopsies in SLE and other connective tissue diseases.

In vivo anti-nuclear antibody (ANA) was observed by direct immunofluorescence microscopy in epithelial cell nuclei in forty-four biopsies from thirty-three patients. The tissue containing the ANA was macroscopically normal in twenty-seven patients. The thirty-three patients with in vivo biopsy ANA included twenty-three with SLE, three with mixed connective tissue disease, two each with multi-system Sjögren''s syndrome, dermatomyositis, and progressive systemic sclerosis, and one with rheumatoid arthritis. Features of sicca syndrome were noted in seventeen patients. The patterns of the in vivo biopsy ANA in the thirty-three patients were speckled (21), homogeneous (6), nodular (2), and both speckled and homogeneous (4). Complement was not detected in the epithelial cell nuclei. Immunoglobulin(s) and/or complement were deposited along the dermoepidermal junction in thirty-two of the forty-four biopsies, and in dermal blood vessels in twenty-two biopsies. Each patient had serum ANA against rat liver substrate; twenty-seven had high titre ANA (1 in 1000 or greater). Elevated levels of DNA-binding were found in twenty patients (61%), but the level of DNA-binding did not correlate with the intensity of in vitro biopsy ANA staining. Serum antibody to ribonucleoprotein (RNP) was present in eight of the twenty-three patients tested (35%), all eight patients having clinical features of sicca syndrome. Hypocomplementaemia was found in thirteen patients (40%), all of whom had active SLE. In vivo biopsy ANA appears to be a real phenomenon of unknown aetiology, and not an artifact, which is found in some patients with active multisystem autoimmune disease, especially SLE.     

Interferon deficiency syndrome.

Activation of the interferon (IFN) system is an early defence mechanism against viral infections. The virus stimulates production of IFN by nucleated cells including the peripheral blood mononuclear cells (PBMC), and this IFN in turn activates several IFN-dependent immune mechanisms including the induction of an anti-viral state in cells, which prevents or retards further intracellular viral replication. In an ongoing study of 1,500 individuals of all ages and with various illnesses, we found 15 cases (representing 5% of patients with acute viral disease) in whom the IFN system response during an acute viral illness was absent or grossly deficient. There was no detectable IFN in the blood, PBMC did not produce IFN-alpha and IFN-gamma or produced minimal amounts of one of them in vitro following appropriate stimulation, and the patients' PBMC were not in an anti-viral state. These patients had severe progressive or fulminant viral disease, often ending fatally. IFN therapy appears to be beneficial in these cases, as it rapidly induced a cellular antiviral state in most cases, stimulated in vitro IFN-alpha and IFN-gamma production by PBMC, and led to rapid recovery in seven of the nine patients who received treatment for at least 3 days. In our opinion IFN replacement therapy should be commenced as early as possible in such cases, and before irreversible cell and organ damage occur.     

Clinical significance of the fluctuation of primary biliary cirrhosis-related autoantibodies during the course of the disease

Abstract

Primary biliary cirrhosis (PBC) is a chronic cholestatic disease characterized by the presence of antimitochondrial antibodies (AMA). PBC-specific antinuclear antibodies (ANA) have been characterized and associated with disease progression and outcome. We evaluated the clinical significance of the presence and serial changes in titers of AMA, PBC-specific ANA (anti-gp210, anti-sp100) and anti-chromatin antibodies. Over a median (IQR) period of 35 (36) months, 512 specimens were collected from 110 patients. Autoantibodies were detected by commercial ELISAs (INOVA Diagnostics). Biochemical, clinical, and histological status were included at initial presentation and during follow-up visits. The Mayo risk score was calculated as a prognostic index at each time point. Liver biopsy findings were classified according to Ludwig’s classification and biochemical response to ursodeoxycholic acid was evaluated according to Pares. At baseline, AMA IgG and IgA, anti-gp210 IgG, anti-sp100 IgG and anti-chromatin IgG were detected in 92/110 (83.6%), 57/110 (51.8%), 5/110 (4.5%), 14/110 (12.7%), and 0/110 (0%) patients, respectively. Positivity for all autoantibodies apart from anti-chromatin, at baseline visit (n?=?110 patients), in all tested sera (n?=?512) as well as increased autoantibodies titers during follow-up were associated with biochemically and/or histologically advanced disease. A decrease of anti-sp100 titers but not of anti-gp210 titers during follow-up was associated with improvement of Mayo risk score (p?=?0.025) and response to ursodeoxycholic acid (p?=?0.016). These results suggest that detection of AMA and PBC-specific ANA was correlated with disease severity. Serial changes of anti-sp100 titers and not of anti-gp210 titers might prove useful for monitoring the disease course and treatment outcome.     

Intermittent interferonemia and interferon responses in multiple sclerosis.

In view of the immunoregulatory and antiviral properties of the interferons (IFNs), the production of and response to these cytokines in vivo and in vitro were assessed in 42 patients with multiple sclerosis (MS), a disease with features of autoimmunity and a viral infection. Serum IFN, determined by bioassay of antiviral activity at 10 intervals over 18 months, was detectable at levels ranging from 16 to 250 IU/ml, at least once and up to five times in 37 of the 42 patients. Of 420 samples tested, 88 (21%) were positive. None of the 71 serum samples from 37 healthy subjects contained detectable IFN activity. Neutralization of antiviral activity by antibodies showed that the serum IFN type was IFN-alpha in 82 samples, IFN-gamma only in 2, and both IFN-alpha and IFN-gamma were present in 4. At the initial time point the activity of 2'-5' oligoadenylate synthetase (OAS), an IFN-induced enzyme, was elevated in peripheral blood leucocytes (PBL) from 13 patients, but not in 7 patients seropositive for IFN, indicating that in some patients there was a failure of PBL to respond to endogenous IFN. In most patients the capacity of PBL in vitro to produce IFNs-alpha/beta or -gamma after induction by virus or mitogens, respectively, was likewise reduced. These various abnormalities in IFN responses could not be correlated with clinical assessments of disease activity but may reflect subclinical attacks. The abnormalities described, in particular the intermittent interferonemia in MS, are more striking than in other diseases previously reported, indicating an unusual component to the stimulus for IFN production (viral or other) or the response to it. The effects of endogenous IFN production may have implications for the scheduling of therapy with IFN in MS.     

Generation of neutralizing mouse anti-mouse IL-18 antibodies for inhibition of inflammatory responses in vivo.

The proinflammatory cytokine IL-18 mediates IFN-gamma production as well as the induction of Th1 polarized immune responses in synergy with IL-12. In this study, we describe the production of isogeneic monoclonal antibodies (Mabs) directed against murine IL-18 (mIL-18). Immunization of IL-18-deficient mice with recombinant mIL-18 in the presence of CpG-oligodeoxynucleotides (CpG-ODN) and alum as adjuvant resulted in high anti-IL-18 serum titers. We could identify two Mabs, SK721-2 and SK113AE-4, which were able to bind to IL-18 and neutralize its IFN-gamma inducing effect in vitro with an IC(50) of 40-100 ng/ml. In vivo, LPS-induced IFN-gamma production was reduced by 60-85% following a single administration of Mabs SK113AE-4 or SK721-2. Since IL-18 is likely to be involved in the pathogenesis of inflammatory diseases such as rheumatoid arthritis or Crohn's disease, neutralizing mouse anti-mouse IL-18 Mabs have the potential to become valuable tools for the therapeutic exploration of long-term IL-18 blockade in vivo.     

Effects of in vivo administration of interferon (IFN)-gamma, anti-IFN-gamma, or anti-interleukin-4 monoclonal antibodies in chronic autoimmune graft-versus-host disease.

These studies examined the role of cytokines in chronic autoimmune graft-versus-host disease (GVHD) in B6D2F1 mice injected with lymphoid cells from DBA/2 mice. Anti-interleukin (IL)-4 and anti-interferon (IFN)-gamma mAb, or IFN-gamma, were used in vivo to modulate B cell hyperactivity and disease. Kinetic experiments showed that, 2-3 weeks after induction, GVH mice had 100x elevated serum IgE, while IgG1 and IgG2a were 10x above normal. Early treatment with anti-IL-4 mAb or IFN-gamma decreased serum IgE and IgG1 and had no effect on IgG2a. Anti-IFN-gamma mAb treatment increased serum IgE and IgG1 while reducing IgG2a. This increase in serum immunoglobulins could be correlated with an increased spontaneous secretion of IL-4, IL-5, and IL-6 in spleen cell cultures from anti-IFN-gamma mAb-treated GVH mice. While neither anti-IFN-gamma nor IFN-gamma treatments altered the disease course, anti-IL-4 treatment delayed proteinuria and death in GVH mice. These observations suggest an important role for IL-4 in immune complex-mediated glomerulonephritis in chronic GVHD.     

Effects of interferon-alpha on the expression of a lupus idiotype in normal humans

Interferon (IFN) has extensive immunoregulatory effects but its role in systemic lupus erythematosus (SLE) remains obscure. The observations that a high proportion of patients with active SLE have increased IFN levels in their sera, and that IFN injected to lupus-prone mice aggrevates their disease, led us to examine the effects of IFN on the production of 16/6--a high frequency idiotype of monoclonal anti-DNA antibodies produced by human-human hybridomas derived from SLE patients. Peripheral blood mononuclear cells (PBMC) of healthy donors or of patients with SLE were incubated with IFN and pokeweed mitogen (PWM). Seven-day supernatants were assayed for total IgM, for IgM with 16/6 idiotype, and for IgM anti-DNA activity. PWM-stimulated PBMC of all healthy donors examined produced the 16/6 idiotype (mean 2.5 ng/ml). A significant increase of 16/6 in normals (above the level with PWM alone) was noted with 10-100 u/ml of IFN-alpha but not with 500 u/ml. In 3/10 normals the addition of IFN-alpha resulted in detectable anti-DNA activity. The IFN-induced increase in 16/6 idiotype was significantly more than the increase in IgM (335% vs 47% above baseline, with 10 u/ml of IFN). These effects of IFN could not be demonstrated in the absence of PWM nor in T-cell-depleted preparations. Recombinant IFN-gamma had no augmenting effect on 16/6 production. Three SLE patients in remission had elevated levels of 16/6 in their PBMC supernatant (15-200 ng/ml) which could not be further augmented by IFN. Thus, we have demonstrated the potential of PWM-stimulated normal lymphocytes to generate a "lupus" idiotype and shown that production of this idiotype requires T cells and is preferentially enhanced by IFN-alpha. Further studies of the effects of IFN on the expression of anti-DNA antibodies may clarify a postulated role of IFN in autoimmune diseases.     

Janus-like effects of type I interferon in autoimmune diseases

In multiple sclerosis, type I interferon (IFN) is considered immune-modulatory, and recombinant forms of IFN-β are the most prescribed treatment for this disease. This is in contrast to most other autoimmune disorders, because type I IFN contributes to the pathologies. Even within the relapsing-remitting multiple sclerosis (RRMS) population, 30-50% of MS patients are non-responsive to this treatment, and it consistently worsens neuromyelitis optica, a disease similar to RRMS. In this article, we discuss the recent advances in the field of autoimmunity and introduce the theory explain how type I IFNs can be pro-inflammatory in disease that is predominantly driven by a Th17 response and are therapeutic when disease is predominantly Th1.     

Enhanced interferon-gamma (IFN) production by lymph node cells from autoimmune (MRL/1, MRL/n) mice.

Interferons (IFNs) have been implicated in the aetiopathogenesis of the autoimmune disease systemic lupus erythematosus (SLE). The ability of unstimulated and Sepharose-bound concanavalin A (ConA) stimulated spleen or lymph node (LN) cells from normal CBA/T6 mice and histocompatible autoimmune strains (MRL/1, MRL/n) of various ages to produce IFN-gamma was measured. Levels of IFN-gamma produced by ConA-stimulated spleen cells from CBA/T6, MRL/1 and MRL/n mice at 6 weeks of age were not statistically different (mean +/- SEM: 786 +/- 182, 1147 +/- 282, 1024 +/- 146 IU/ml, respectively). At this age only stimulated LN cells from MRL/l mice produced detectable IFN-gamma (538 +/- 44 IU/ml) and these levels remained constant up to 6 months. IFN production by stimulated LN cells from young MRL/n mice (66 +/- 21 IU/ml at 3 months, 44 +/- 41 IU/ml at 6 months) increased at 1 year (463 +/- 97 IU/ml) corresponding to the age of disease onset. The failure of stimulated CBA/T6 LN cells to produce IFN-gamma was not due to cell-cell suppression, defective IL-2 production or the generation of soluble inhibitors. Stimulated LN cells from other normal inbred (C57Bl/6, Balb/c, A/J) outbred and FI hybrid mouse strains (Swiss, [Swiss x Balb/c] F1, (CBA/T65 x C57Bl/6]FI) produced undetectable or low levels of IFN compared to MRL/1 and MRL/n mice. These results show that autoimmune mouse LNs generate more IFN compared to normal controls and that the increase in IFN levels (at least in MRL/n) corresponds to the age of disease onset.     

Enzyme-linked immunoassay using recombinant trans-sialidase of Trypanosoma cruzi can be employed for monitoring of patients with Chagas' disease after drug treatment

trans-Sialidase is an enzyme present on the surface of Trypanosoma cruzi and is an important antigen recognized by sera from patients with Chagas' disease. In the present study we investigated whether the benznidazole treatment of patients with Chagas' disease induced changes in the reactivity of serum toward a recombinant form of trans-sialidase in order to develop an assay for monitoring of patients after treatment for Chagas' disease, which is needed at Chagas' disease control centers. By using an enzyme-linked immunosorbent assay containing a recombinant protein corresponding to the catalytic domain of trans-sialidase, we found that the antigen had a high specificity for sera from untreated patients with Chagas' disease. Sera from healthy individuals or patients with active visceral leishmaniasis minimally cross-reacted with the antigen. Anti-trans-sialidase immunoglobulin was detected in 98% of 151 untreated patients with Chagas' disease. Of these, 124 patients were treated for 60 days with benznidazole (5 mg/kg of body weight/day), and their sera were assayed for reactivity with the recombinant trans-sialidase. By using this methodology, three groups of patients could be established. The first group (60 patients), which was considered to have been successfully treated, showed no reactivity after treatment. The second group (46 patients) still showed signs of infection, and after treatment their sera recognized trans-sialidase, but with reduced titers. The third group (18 patients) was considered to be resistant to drug treatment, and their sera presented identical reactivities before and after treatment. These results suggest that determination of the absence of antibodies to recombinant trans-sialidase in treated patients by the present assay is indicative of treatment success, while the presence of antibodies may indicate the persistence of infection. Therefore, this method may be useful for the diagnosis and monitoring of patients undergoing benznidazole treatment.