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Several studies correlated genetic background and pancreatic islet-cell autoantibody status (type and number) in type 1A diabetes mellitus (T1AD), but there are no data evaluating the relationship among these markers with serum cytokines, regulatory T cells and β cell function. This characterization has a potential importance with regard to T1AD patients' stratification and follow-up in therapeutic prevention. In this study we showed that peripheral sera cytokines [interleukin (IL)-12, IL-6, II-1β, tumour necrosis factor (TNF)-α, IL-10] and chemokines (CXCL10, CXCL8, CXCL9, CCL2) measured were significantly higher in newly diagnosed T1AD patients when compared to healthy controls (P < 0·001). Among T1AD, we found a positive correlation between CXCL10 and CCL-2 (r = 0·80; P = 0·000), IL-8 and TNF-α (r = 0·60; P = 0·000); IL-8 and IL-12 (r = 0·57; P = 0·001) and TNF-α and IL-12 (r = 0·93; P = 0·000). Glutamic acid decarboxylase-65 (GAD-65) autoantibodies (GADA) were associated negatively with CXCL10 (r = -0·45; P = 0·011) and CCL2 (r = -0·65; P = 0·000), while IA-2A showed a negative correlation with IL-10 (r = -0·38; P = 0·027). Human leucocyte antigen (HLA) DR3, DR4 or DR3/DR4 and PTPN22 polymorphism did not show any association with pancreatic islet cell antibodies or cytokines studied. In summary, our results revealed that T1AD have a proinflammatory cytokine profile compared to healthy controls and that IA-2A sera titres seem to be associated with a more inflammatory peripheral cytokine/chemokine profile than GADA. A confirmation of these data in the pre-T1AD phase could help to explain the mechanistic of the well-known role of IA-2A as a more specific marker of beta-cell damage than GADA during the natural history of T1AD., (© 2011 The Authors. Clinical and Experimental Immunology © 2011 British Society for Immunology.)

Induced oral tolerance to mucosal-exposed antigens in immunized animals is of particular interest for the development of immunotherapeutic approaches to human allergic diseases. This is a unique feature of mucosal surfaces which represent the main contact interface with the external environment. However, the influence of oral tolerance on specific and natural polyreactive IgA antibodies, the major defense mechanism of the mucosa, is unknown. We have shown that oral administration of an extract of the dust mite Dermatophagoides pteronyssinus (Dp) to primed mice caused down-regulation of IgE responses and an increase in tumor growth factor-beta secretion. In the present study, we observed that primed inbred female A/Sn mice (8 to 10 weeks old) fed by gavage a total weight of 1.0-mg Dp extract on the 6th, 7th and 8th days post-immunization presented normal secretion of IL-4 and IL-10 in gut-associated lymphoid tissue and a decreased production of interferon gamma induced by Dp in the draining lymph nodes (13,340 +/- 3,519 vs 29,280 +/- 2,971 pg/ml). Mice fed the Dp extract also showed higher levels of serum anti-Dp IgA antibodies and an increase of IgA-secreting cells in mesenteric lymph nodes (N = 10), reflecting an increase in total fecal IgA antibodies (N = 10). The levels of secretory anti-Dp IgA antibodies increased after re-immunization regardless of Dp extract feeding. Oral tolerance did not interfere with serum or secretory IgA antibody reactivity related to self and non-self antigens. These results suggest that induction of oral tolerance to a Dp extract in sensitized mice triggered different regulatory mechanisms which inhibited the IgE response and stimulated systemic and secretory IgA responses, preserving the natural polyreactive IgA antibody production.

We studied the effect of oral and portal vein administration of alloantigens on mouse skin allograft survival. Graft receptor BALB/c mice received spleen cells (30, 90, 150 or 375 x 10(6)) from donor C57BL/6 mice intragastrically on three successive days, starting seven days before the skin graft. Allograft survival was significantly increased with the feeding of 150 x 10(6) allogeneic spleen cells by one gavage (median survival of 12 vs 14 days, P< or =0.005) or when 300 x 10(6) cells were given in six gavage (12 vs 14 days, P<0.04). A similar effect was observed when 150 x 10(6) spleen cells were injected into the portal vein (12 vs 14 days, P< or =0.03). Furthermore, prolonged allograft survival was observed with subcutaneous (12 vs 16 days, P< or =0.002) or systemic (12 vs 15 days, P< or =0.016) application of murine interleukin-4 (IL-4), alone or in combination with spleen cell injection into the portal vein (12 vs 18 days, P< or =0.0018). Taken together, these results showed that tolerance induction with spleen cells expressing fully incompatible antigens by oral administration or intraportal injection partially down-modulates skin allograft rejection. Furthermore, these findings demonstrated for the first time the effect of subcutaneous or systemic IL-4 application on allograft skin survival suggesting its use as a beneficial support therapy in combination with a tolerance induction protocol.

Background: Maternal exposure to environmental ubiquitous allergens could exert an influence on the newborn's immune repertoire and the later development of allergy. The aim of this study was to investigate the effects of maternal immunization with Dermatophagoides pteronyssinus (Dp) on the hypersensitivity response and IgG subclass production in offspring using a murine model., Methods: A/Sn mice were immunized with Dp before mating with normal A/Sn males. Diaplacental serum samples were collected from newborn mice delivered by cesarean section, and maternal milk samples were extracted from the stomachs of newborn mice. Groups of offspring 25 or 45 days old were Dp immunized and boosted on the 10th day after sensitization. The animals were bled 7 days after the booster., Results: High levels of anti-Dp IgG subclasses - mainly IgG1, but also IgG2a and IgG2b - were transmitted by immunized mice via the placenta to the offspring. In the milk from immunized mothers, significant levels of anti-Dp IgG subclasses and anti-Dp IgM and IgA antibodies were detected. Moreover, the increase in total IgA antibodies in the milk of the immunized females correlated with a significantly increased level of TGF-beta1. TGF-beta2 levels were markedly higher than the beta1 isoform in the milk, although no difference was observed between the groups. When offspring from immunized mothers were sensitized at 25 days, a significant decrease in total and anti-Dp IgE antibodies as well as total and anti-Dp IgG1, IgG2a and IgG2b subclasses was observed compared to normal female offspring, whereas when offspring were sensitized at 45 days, both offspring groups showed similar levels of IgE and IgG subclasses., Conclusions: Our study showed that maternal immunization with Dp promotes the transference of specific antibodies and/or TGF-beta, which can negatively modulate the allergic response in offspring, and suggests that maternal preexposure to allergen before mating can protect mice during the early phase., (Copyright 2002 S. Karger AG, Basel)

Oral antigen administration induces peripheral tolerance in naive animals. Studies of oral tolerance induction in sensitized mice have clinical relevance as a strategy to modulate allergy. In this study, the A/Sn mice sensitized with extract of Dermatophagoides pteronyssinus (Dp) and submitted to oral Dp administration showed a marked decrease in IgE anti-Dp antibody production compared with sensitized phosphate-buffered saline (PBS)-fed mice. T cells from Dp-fed mice cocultured with spleen cells from PBS-fed mice were able to inhibit IgE anti-Dp antibody production and did not interfere in IgG1 antibody levels. The analysis of cytokine profile after Dp feeding showed a significant decrease in interleukin-4 (IL-4), IL-5, and IL-13 antigen-induced secretion levels by spleen cells, without shifting to IL-2 and interferon-gamma (IFN-gamma) production. Both transforming growth factor-beta (TGF-beta) baseline and TGF-beta antigen-stimulated levels were increased in Dp-fed mice. The effects of regulatory cytokines on anti-Dp IgE antibody production were investigated in vitro. The addition of recombinant TGF-beta (rTGF-beta) to spleen cell cultures stimulated by Dp inhibited IgE antibody secretion in both mouse groups. Neutralizing antibodies to IL-4, but not anti-TGF-beta, induced a marked inhibition of IgE production. Therefore, a negative modulatory effect on IgE response by inhibition of the axis Th2 was observed in sensitized Dp-fed mice, possibly mediated by induction of regulatory cytokines.

The current therapy for common variable immunodeficiency is based on the administration of intravenous immunoglobulin preparations which may cause severe adverse reactions. Some reports have associated these reactions with IgG anti-IgA antibodies, although this is not yet clear. We analyzed 20 sera from common variable immunodeficiency patients by an enzyme immunoassay to detect IgG anti-IgA and determine its subclass profile. Five patients presented high levels of these antibodies, all of them had IgG1, two had IgG2 and IgG4 and one had IgG3. Three of these five patients were receiving non IgA depleted intravenous immunoglobulin and had no severe adverse reactions. One patient had persisted with similar high levels of IgG anti-IgA during three years. Therefore, the IgG anti-IgA antibodies, regardless to their subclass profile in the common variable immunodeficiency patients sera do not seem to be associated with severe adverse reactions to intravenous immunoglobulins.

Human immunoglobulin preparations have been used in a number of clinical settings with good results, although in many of them the mechanism of action is not yet known. One possible mechanism is the modulation of cytokine activity. This study investigated the presence of inhibitory activity in intravenous immunoglobulin (IVIg) and F(ab')2 fragment preparations to two cytokines, tumor necrosis factor-alpha (TNF-alpha) and interleukin-2 (IL-2). Cytotoxic activity of human recombinant TNF-alpha or TNF-alpha secreted by peripheral blood mononuclear cells (PBMC) on L929 cells and the proliferative activity of the IL-2 on CTLL-2 cells were examined. Human serum albumin (HSA) was used as control. F(ab')2 inhibited, in a dose-dependent fashion, the TNF-alpha activity secreted by PBMC serial dilutions or, at the higher concentrations (25 and 10 mg/ml), recombinant TNF-alpha activity. In contrast, IVIg was able to inhibit only at 25 and 10 mg/ml the TNF-alpha activity secreted by any PBMC dilution tested, and did not inhibit the recombinant TNF-alpha activity. With IL-2, however, even HSA was able to inhibit its proliferative activity, possibly through a carrier effect. The IVIg inhibition of IL-2 activity was not different from that of HSA, but F(ab')2, at 12.5 mg/ml, was capable of inhibiting significantly more the IL-2 activity than HSA. Our results suggest an anticytokine effect of the immunoglobulin preparations that this activity may be mainly mediated by variable regions of the immunoglobulins, and that the more pronounced effect of F(ab')2 may be due to its greater molar concentration compared to intact IgG molecules.

Nineteen Brazilian HIV-infected hemophiliacs and their stable heterosexual sexual partners were studied with the aim of assessing the rate of HIV transmission in this at risk group. The mean length of relationship between couples was 7.4 years. The hemophiliac men were Class II (n = 6), III (n = 11) and IVa (n = 2) of the CDC classification. They had decreased CD4+ and elevated CD8+ cell numbers; five had p24 antigenemia. We found 3 HIV-infected women (15.8 percent) by routine and confirmatory tests, a prevalence similar to that seen in other countries. They were asymptomatic and had no detectable p24 antigenemia. The 3 seropositive women's partners were Class II and III-CDC, and had normal CD4+ and CD8+ values and no p24 antigenemia. All seronegative women also had normal CD4+ and CD8+ numbers, except for elevated CD8+ cells in three of them, but immune abnormalities had already been seen in some seronegative partners at high risk for HIV infection. Our results reinforce previous suggestions that heterosexual transmission to stable female partners occurs preferentially early after initiation of sexual exposure, and possibly when the transmitter had high levels of viremia and regular sexual activity.

We previously reported that infection of BALB/c mice with the parasite Plasmodium chabaudi induces high production of natural autoantibodies. Here we demonstrate that such an infection of lupus-prone (NZB x NZW)F1 (B/W) mice retards the development of their autoimmune disease. Survival and disease hallmarks (high-grade proteinuria and IgG anti-DNA antibodies) were delayed for 6 months when parasite inoculation was given at either 3 or 7 months of age, i.e. before or after the onset of the clinical symptoms. Similar beneficial effects, although less pronounced, were obtained when mice were treated with a total of 800 micrograms of IgG (P-IgG) or IgM (P-IgM) or 300 micrograms of cryoglobulin preparations isolated from P. chabaudi-infected BALB/c mice while similarly prepared fractions from uninfected mice had little effect. Compared to these fractions, P-IgG and P-IgM contained higher levels of natural antibodies bearing the D23 idiotype characteristic of polyreactive natural autoantibodies with enhanced activity against Fab and Fc fragments of IgG. In surviving mice, the level of anti-DNA antibodies, particularly those of IgG1 isotype, were significantly decreased. Flow cytometric analysis of various T cell subsets showed that the number of cells expressing gamma delta T cell receptor (TcR) antigens which did not vary with age was not modified after P-IgG or P-IgM treatment. In contrast, the number of T cells expressing V beta 8.1,2,V beta 10 and V beta 14 TcR antigens, which increased with age, were significantly reduced. Taken together, these results indicate that parasite infection of mice induces the synthesis of populations of IgM and IgG natural autoantibodies with immunoregulatory properties and that these antibodies attempt, at least transitorily, to rescue a natural autoantibody network that is deficient in B/W mice.

Peripheral blood mononuclear cells (PBMC) from acute leptospirosis patients with and without acute renal failure were studied in order to investigate the status of cellular immunity in this disease. We analyzed the lymphocyte subsets of leptospirosis patients by immunofluorescence and their responsiveness to the mitogens phytohemagglutinin (PHA) and pokeweed mitogen (PWM). Additionally, we investigated the effect of the patients' sera on normal PBMC proliferative response. We observed a decrease in the CD3+ and CD4+ cell subsets in patients with and without acute renal failure, or in percentage values alone in those who had recovered from renal failure. An increase in the number of B lymphocytes was observed in all patients, compared with controls. This increase in B lymphocytes was seen even in patients who had recovered from renal failure, when the number of CD3+ and CD4+ lymphocytes had already returned to normal levels. The low PHA response observed only with lymphocytes from patients with acute renal failure suggests a suppressive effect. The proliferative response to PWM was comparable to controls, even in the patients with acute renal failure. This latter result and the expansion of the B cell number could be related to leptospiral-derived factor(s). We also showed that sera from patients with and without acute renal failure exerted some inhibitory activity on normal PBMC responses to PHA and PWM. Although the redistribution of lymphocyte subsets and the serum suppressor activity were related to acute renal failure and leptospiral factor(s), we suggest that the cellular immune system was not irreversibly affected, which is compatible with the good prognosis seen in the patients studied.

The objective of the present study was to determine whether cimetidine, a type-2 histamine receptor antagonist, inhibits the immunological enhancement of allografted rats achieved by treatment with donor antigen plus anti-donor antibody. Groups of rats submitted to this active-passive enhancement protocol and treated ip with 30 (APEC 30; Group I; N = 4) or 60 (APEC 60; Group II; N = 8) mg/day cimetidine for 14 days had a significantly shorter graft survival (20.2 +/- 5.1 and 11.1 +/- 2.6 days, respectively) than the control group (animals submitted to the enhancement protocol and killed on day 72 after transplant when the graft was beating normally; APE; Group III; N = 6; P less than 0.05). On the other hand, these animals had a significantly longer graft survival than rats allotransplanted but not treated for enhancement (ALLO; Group V; N = 5; 8.2 +/- 0.8 days). The surgical control, consisting of isotransplanted animals, had a long-term survival (ISO; Group VI; N = 6; rats killed 120 days after transplant with the graft beating normally). Animals treated with cimetidine, but not submitted to the enhancement protocol (AC 60; Group IV, N = 4) had a significantly shorter graft survival (6.25 +/- 0.5) than the allotransplanted animals (Group V). These results indicate inhibition of the suppressor mechanisms which participate in this type of immunological enhancement.

Monoclonal antibodies (Mabs) were produced against human T cell membrane antigens. Sixteen Mabs were studied and six were selected for immunohistochemical assays on paraffin-embedded tonsil sections. Two Mabs (2D7 and 1E2) specifically recognized T-lymphocyte areas in sections of pathological tissues originating from lymphoproliferative diseases, and reacted with proteins of approximately 80 kDa. Most of the Mabs produced thus far are only suitable for immunohistochemical assays on frozen section. Only a few Mabs recognize lymphoid markers on paraffin-embedded sections, a procedure which permits a more extensive and practical application of Mabs in clinical diagnosis. These antibodies should be valuable in diagnosing T cell-related diseases and their large scale production should reduce laboratory costs because all reagents currently available are imported.

The present paper describes the clinical and laboratory follow-up of 11 patients with the diagnosis of common variable immunodeficiency. Their age varied from 8 to 45 years. The mean disease time was 12.6 years and mean diagnosis time 4.3 years. Infectious manifestations, mainly of the respiratory and digestive tracts, occurred in all patients. Polyadenomegaly was noted in seven, hepatomegaly in six, splenomegaly in five and arthralgia in four patients. All of them presented serum IgG less than 250 mg/dl. IgA less than 33 mg/dl and IgM less than 31 mg/dl, except one with IgM = 176 mg/dl. The isohaemagglutinin titers were less than 1/20 in all but one patient. The determination of the number of B lymphocytes in the peripheral blood revealed normal counts in three, elevated in one and decreased in five patients. The CD-4/CD-8 ratio was less than 1 in 8 and greater than 1 in three of them. Five patients had positive cutaneous late reactions to at least one of the following antigens: PPD, SK-SD (Varidase), Trichophytin and Levedurin (Candidin). A decrease of the proliferative activity of peripheral blood mononuclear cells stimulated by lectins (PHA, Con-A, PWM) was also noted. Natural killer function was decreased. The association a possible role of regulatory lymphocytes in the immunopathogenesis of this disease. The data presented here emphasize the diversity of clinical and immunological manifestations of this disease, which could be noted between diverse patients and in the follow-up of a single one. In our cases the disease had an evolutive character, with a primarily humoral dysfunction followed by cellular immunity disturbances that determined poorer prognosis and progressive difficulties in the therapeutics. We suggest a conceptual reevaluation of this condition and a new denomination, for instance "Late-Onset Combined Immunodeficiency". The long delay between the initial clinical manifestations of the disease and its diagnosis was a handicap for an adequate treatment. Early intervention could certainly decrease the morbidity and mortality of the disease.