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Background Large local reaction to Hymenoptera stings is usually defined as a swelling >10 cm which lasts longer than 24 hours, sometimes associated with erythema, pruritus and blisters. Currently, the risk of subsequent systemic reactions after re-stings is considered low (2%-15%). Therefore, a diagnostic workup in case of large local reaction is often judged unnecessary, as well as adrenaline auto-injector and venom immunotherapy prescription. The aim of this study was to prospectively evaluate the outcome of re-stings in a real-world setting, in patients with a history of one previous large local reaction. Methods We consecutively enrolled patients who experienced their first large local reaction (as per EAACI definition), treated with antihistamine and steroids. They were followed for field re-stings and assessed for risk of subsequent systemic reactions. Results We enrolled 662 patients. Out of the 225 re-stung subjects, 24% did not experience reactions, 52% reported a second large local reaction and 24% had systemic reactions. The risk of subsequent systemic reactions was higher in case of skin test reactivity to Apis mellifera or Vespula species (OR 2.1 and 3.8, respectively), in particular if positive at 0.001 µg/mL concentration (OR 13.4 and 16.5, respectively). Conclusions Systemic reactions, after a previous large local reaction, occur more frequently than that reported by literature. After analysing the predictive role of large local reactions for systemic reactions, we demonstrated that an accurate diagnostic workup may be considered, particularly skin tests. Further studies in different countries are needed to confirm these results and large local reaction management.

Shellfish allergy is an important cause of food allergies worldwide. BothTo investigate the features of shrimp-allergic patients either reactive or tolerant to mollusks, with the currently available diagnostic methods.Nineteen centers, scattered throughout Italy, participated in the real-life study, enrolling patients allergic to shrimp with or without associated reactions to mollusks. Patients underwent skin tests using commercial extracts or fresh raw and cooked shrimp and mollusks, and IgE reactivity to currently available allergenic extracts and molecules was measuredTwo hundred and forty-seven individuals with a self reported adverse reactions to shrimp participated in the study; of these 47.8% reported an adverse reaction to mollusks ingestion (cephalopod and/or bivalve). Neither of the tests used,The current diagnostic methods are inadequate to predict the cross-reactivity between crustaceans and mollusks. The detection of mollusks hypersensitivity should still rely on skin tests with fresh material. The exclusion of mollusks from shrimp allergic patients' diets should occur when clinical history, available diagnostic instruments, and/or tolerance tests support such a decision.

Human CD4+ T cell clones secreting different patterns of cytokines similar to TH1 and TH2 cells described in mice have been demonstrated. These human TH1 and TH2 clones are produced in response to different antigens and exhibit distinct functional properties. TH1 clones are produced in response to intracellular bacteria and viruses, do not provide help for IgE production and possess cytolytic potential, whereas TH2 clones are produced in response to allergens and helminth components, provide optimal help for IgM, IgG, IgA and IgE synthesis, and lack cytolytic potential. The cytokine profile of 'natural' immunity evoked by intracellular parasites and viruses through the activation of macrophages and NK cells probably determines the phenotype of the subsequent specific immune (TH1) response. TH1 cells are not only involved in the protection against intracellular parasites but also play a role in the genesis of some organ-specific autoimmune diseases, such as Hashimoto's thyroiditis. In contrast, TH2 cells are responsible for the initiation of the allergic cascade.

President John F. Kennedy (JFK) had a complex medical history that is now thought to be an autoimmune polyglandular syndrome type 2 with Addison’s disease and hypothyroidism. He also had gastrointestinal symptoms from adolescence, which now fit well with coeliac disease. In addition, he had a chronic back problem, which contributed to a chronic pain syndrome. This review looks at JFK’s various diseases and focusses on the history of coeliac disease, as well as its presentation. JFK’s Irish ancestry supports the hypothesis of a coeliac disease started early in his youth.

Buckwheat (Fagopyrum esculentum) is a gluten-free grain with acclaimed benefi-cial effects on human health. Our aim was to assess the effect of buckwheat products on intestinal/extra-intestinal symptoms and biochemical parameters in patients with Non-Celiac Gluten Sensitivity (NCGS).A randomized, crossover trial with two intervention phases was conducted on 19 NCGS patients over a 12 week-period. The participants were assigned to consume products made from buckwheat or to maintain their normal gluten-free diet for 6 weeks in a random order. Symptoms due to NCGS were evaluated using two questionnaires.During the intervention period with buckwheat products, patients experienced a signifi-cant decrease in the severity of abdominal pain and bloating (p=0.03). In contrast, the control group showed a significant worsening trend for the majority of NCGS symptoms such as nausea, headache, joint/muscle pain, and attention disorders. The replacement diet with buckwheat products also resulted in a significant increase of serum magnesium (+4.7%) and a significant reduction in the circulating levels of some pro-inflammatory cytokines such as interferon gamma (-33.3%) and monocyte chemotactic protein-1 (-46.5%).The study supports the positive effects of buckwheat for NCGS patients, showing that this alternative cereal can contribute to the re-duction of both negative gastro-intestinal and related symptoms, and nutritional deficiencies, and lead to an im-provement in inflammatory profile.

Background: Shrimp is a frequent cause of food allergy worldwide. Besides tropomyosin, several allergens have been described recently. Objective: We investigated which allergens are involved in Italian shrimp-allergic adults. Methods: Sera from 116 shrimp-allergic patients selected in 14 Italian allergy centers were studied. Skin prick tests with house dust mite (HDM) as well as measurements of IgE to Pen a 1 (shrimp tropomyosin) and whole shrimp extract were performed. All sera underwent shrimp immunoblot analysis, and inhibition experiments using HDM extract as inhibitor were carried out on some Pen a 1-negative sera. Results: Immunoblots showed much variability. IgE reactivity at about 30 kDa (tropomyosin) was found in 90 kDa was frequent. Further reactivities at 14–18, 25, 43–50, about 60 and about 80 kDa were detected. Most subjects had a history of shrimp-induced systemic symptoms irrespective of the relevant allergen protein. IgE to Pen a 1 were detected in sera from 46 (41%) patients. Skin reactivity to HDM was found in 43/61 (70%) Pen 1-negative subjects and inhibition studies showed that pre-adsorption of sera with HDM extract induced a marked weakening of the signal at >67 kDa. Conclusions: Several allergens other than tropomyosin are involved in shrimp allergy in adult Italian patients. Some hitherto not described high molecular weight allergens seem particularly relevant in this population and their cross-reactivity with HDM allergens makes them novel potential panallergens of invertebrates.

International audience; Background: In ascertained allergic sensitization to Vespa crabro (VC) venom, the European guidelines still consider venom immunotherapy (VIT) with Vespula (VE) venom sufficient to achieve an adequate protection against VC. However, antigen 5 immunoblotting studies showed that a genuine sensitization to VC venom may exist. In such cases, a specific VC venom would be preferable for VIT treatment. Since in the last few years, VC venom extracts became available for diagnosis and desensitization, we assessed the efficacy and safety of VIT with a VC-VIT, compared to VE extract. Methods: Patients stung by VC, and carefully diagnosed for specific sensitization and indication to VIT underwent a 5-year course of immunotherapy with either VE or VC extracts. The severity of reactions at the first sting (pre-VIT) and after field re-stings (during VIT) were compared. Results: Eighty-three patients, treated with VE extract and 130 patients treated with VC extract completed the 5-year course of VIT. Only a fraction of those patients (43,8%) were field-re-stung by VC: 64 patients on VC VIT and 69 on VE VIT. In the VC VIT group, reactions at re-sting were: 50 negative, 12 large local reactions, 4 systemic reactions (Muller grade I). In this group the VC VIT efficacy was 93,8%. In the VE VIT treated group the reactions at VC re-sting were: 51 negative, 10 large local reactions and 9 systemic reactions (5 Muller I, 3 Mueller III, 1 Muller IV). In this group the overall efficacy of VIT was 87,0%. The difference in efficacy between the two groups was not statistically significant, as previously reported in literature. Nonetheless, field sting systemic reactions Muller III and IV were recorded only in those patients receiving VE VIT. Conclusion: This observation suggests that in patients with ascertained VC-induced allergic reactions a specific VC VIT, where available, would be more adequate, at least concerning the safety profile.

Background Sublingual immunotherapy (SLIT) proved effective and safe in respiratory allergy, and thus its use in hymenoptera allergy can be hypothesized. Objective We sought to assess, in a proof-of-concept study, whether SLIT might potentially be beneficial in hymenoptera allergy. The sting challenge in large local reactions (LLRs) was used to test this hypothesis. Methods We performed a randomized, double-blind, placebo-controlled study involving patients with LLRs who were monosensitized to honeybee. After the baseline sting challenge, they were randomized to either SLIT or placebo for 6 months. The treatment (Anallergo, Florence, Italy) involved a 6-week build-up period, followed by maintenance with 525 μg of venom monthly. The sting challenge was repeated after 6 months. Results Thirty patients (18 male patients; mean age, 44.5 years) were enrolled, and 26 completed the study, with 1 dropout in the active group and 3 dropouts in the placebo group. In the active group the median of the peak maximal diameter of the LLRs decreased from 20.5 to 8.5 cm ( P = .014), whereas no change was seen in the placebo group (23.0 vs 20.5 cm, P = not significant). The diameter was reduced more than 50% in 57% of patients. One case of generalized urticaria occurred in a placebo-treated patient at sting challenge. No adverse event caused by SLIT was reported. Conclusion Honeybee SLIT significantly reduced the extent of LLRs, and its safety profile was good. Although LLRs are not an indication for immunotherapy, this proof-of-concept study suggests that SLIT in hymenoptera allergy deserves further investigation. Trials involving systemic reactions and dose-ranging studies are needed.

Human CD4+ T cell clones secreting different patterns of cytokines similar to TH1 and TH2 cells described in mice have been demonstrated. These human TH1 and TH2 clones are produced in response to different antigens and exhibit distinct functional properties. TH1 clones are produced in response to intracellular bacteria and viruses, do not provide help for IgE production and possess cytolytic potential, whereas TH2 clones are produced in response to allergens and helminth components, provide optimal help for IgM, IgG, IgA and IgE synthesis, and lack cytolytic potential. The cytokine profile of ‘natural’ immunity evoked by intracellular parasites and viruses through the activation of macrophages and NK cells probably determines the phenotype of the subsequent specific immune (TH1) response. TH1 cells are not only involved in the protection against intracellular parasites but also play a role in the genesis of some organ-specific autoimmune diseases, such as Hashimoto’s thyroiditis. In contrast, TH2 cells are responsible for the initiation of the allergic cascade.

A large series of T cell clones (TCC) specific for purified protein derivative (PPD) of Mycobacterium tuberculosis (total 60) or Toxocara canis excretory/secretory (TES) antigen (total 69) were established from the peripheral blood of two healthy individuals and analyzed for their profile of cytokine production in response to stimulation with either the specific antigen or the polyclonal activator phorbol myristate acetate plus anti-CD3 antibody. Under both these experimental conditions, the great majority of PPD-specific TCC secreted IL-2 and IFN-gamma but not, or limited amounts of, IL-4 and IL-5. In contrast, most TES-specific TCC secreted IL-4 and IL-5 but not, or limited amounts of, IL-2 and IFN-gamma. PPD-specific TCC that failed to secrete IL-4 and IL-5, and TES-specific TCC that failed to secrete IL-2 and IFN-gamma, were found to lack transcripts for IL-4 and IL-5, or for IL-2 and IFN-gamma, respectively. During the course of the study, over a 6-mo period, the functional phenotype of both TES- and PPD-specific TCC was repeatedly assessed and remained constant. These data demonstrate that T cells with stable Th1 or Th2 functional pattern exist not only in mice but also in humans and suggest that in the course of natural immunization certain infectious agents preferentially expand T cell subsets with stable and definite profile of cytokine production.

We have established a large panel of T-cell clones (TCCs) specific for Dermatophagoides pteronyssinus and Lolium perenne group I grass pollen allergens (total, 61) and for tetanus toxoid and protein purified derivative bacterial antigens (total, 38) from the peripheral blood of two atopic individuals and then analyzed their ability to produce interleukin 4 (IL-4), IL-5, and interferon gamma (IFN-gamma). Upon stimulation with phorbol 12-myristate 13-acetate plus anti-CD3 antibody, the great majority of TCCs specific for bacterial components was able to produce both IL-4 and IFN-gamma, whereas most D. pteronyssinus- and L. perenne group I-specific TCCs produced IL-4, but no, or limited, IFN-gamma. Moreover, the mean amounts of IL-4 and IFN-gamma released by allergen-specific TCCs were significantly higher and lower, respectively, than the mean amounts produced by TCCs specific for bacterial components. Under the same experimental conditions, virtually all allergen-specific TCCs, but only one-third of tested TCCs specific for bacterial components, expressed IL-5 RNA and secreted IL-5 in their supernatants. Eighteen TCCs (nine specific for allergens and nine specific for bacterial components) were also assessed for their ability to induce IgE synthesis by autologous B cells in response to stimulation with the specific antigen. Under these experimental conditions, all allergen-specific TCCs, but only one-third of TCCs specific for bacterial components that produced IL-4 but no, or little, IFN-gamma induced the synthesis of detectable amounts of IgE. The demonstration that most allergen-specific helper T cells in atopic individuals are able to produce high amounts of IL-4 (and IL-5), but no IFN-gamma, may explain why allergens induce production of IgE antibodies and increase eosinophils.

Phytohemagglutinin (PHA)-induced human T cell clones (TCC) derived from conjunctival flogistic tissues of 3 patients with vernal conjunctivitis produced unusually high amounts of interleukin-4 (IL-4) and no, or limited amounts of, gamma-interferon (IFN-γ). Allergen (Dermatophagoides pteronyssinus or Lolium perenne group I)-specific TCC derived from peripheral blood of two atopic donors produced significantly higher amounts of IL-4 and significantly lower amounts of IFN-γ than TCC specific for bacterial antigens (tetanus toxoid and PPD) contemporarily established from the same donors. These data provide evidence for a compartimentalization of Th2-like helper T cells in target organs and in the allergen-specific T cell repertoire of allergic patients. Non-B, non-Tbone marrow cells could produce IL-4, but not IL-2 or IFN-γ, in response to cross-linkage of Fcε type I receptors. These cells may further contribute to the maintenance and amplification of allergic inflammation.

Three human T cell clones (TCC) specific for purified protein derivative of Mycobacterium tuberculosis were incubated in the presence of polybrene and phytohemagglutinin with irradiated mononuclear cells from one individual exhibiting seropositivity for human immunodeficiency virus (HIV) and high levels of circulating p24 antigen. After three weeks, TCC showed HIV integration in their DNA, as shown by polymerase chain reaction analysis and Southern blot technique. All the three HIV-infected TCC maintained their ability to recognize the specific antigen, even if their proliferative ability was reduced. The ability of the HIV-infected TCC to produce IL-2, IL-4 and IFN-gamma in response to phorbol myristate acetate plus anti-CD3 monoclonal antibody was decreased, whereas their ability to produce TNF-alpha was unaffected or even enhanced. Two out of the three HIV-infected TCC showed the ability to provide helper function for polyclonal immunoglobulin production when cocultured with autologous B cells in the absence of any stimulant. These data suggest that in vitro infection of normal human TCC may provide a useful model for the study of immunological alterations induced by HIV.

Typically, autoimmune hepatitis (AIH) arises in young women, but recent papers have shown that it can affect older people too. The authors describe a case of AIH in a 70 ys old man affected by acute cholostatic hepatitis. The diagnosis of type I AIH was based on immunological features (high levels of ANA) together with histological picture in the absence of other known causes of hepatitis. Corticosteroid therapy is an effective treatment of type I AIH in older patients. AIH should be considered for the diagnosis of hepatitis in older male patients too.

Infection of CD4+ T cells by human immune deficiency virus-1 (HIV-1) causes severe dysfunction of cellular immunity, but paradoxically results in intense polyclonal activation of B cells, possibly accounting for both hypergammaglobulinaemia and frequent development of B-cell malignancies seen in HIV-infected patients. We have reported that human CD4+ T-cell clones infected with HIV in vitro markedly stimulate immunoglobulin synthesis by B cells through a non-cognate, contact-dependent mechanism. We show here that HIV-infected T-cell clones do not express the CD40 ligand (CD40L), a molecule critical for non-cognate B-cell activation, but a small proportion of them do express membrane tumour-necrosis factor (TNF)-alpha. The ability of HIV-infected T-cell clones to induce polyclonal B-cell activation appears to be restricted to TNF-alpha-positive T blasts and is inhibited by antibodies against both TNF-alpha and TNF-alpha receptor. Freshly isolated CD4+ T cells from HIV-infected individuals express TNF-alpha on the cell membrane and induce TNF-alpha-mediated immunoglobulin production by B cells. Thus, membrane TNF-alpha seems to be involved in the polyclonal B-cell activation induced by HIV-infected T cells.

We investigated the infection of peripheral blood mononuclear cells (PBMNC) by hepatitis C virus (HCV) in 5 patients with HCV-related chronic hepatitis. The presence of HCV-RNA-positive and -negative strands was tested with the polymerase chain reaction (PCR) method. In all subjects, HCV-RNA was shown in PBMNC. In 3 cases, HCV-RNA was shown in the T- and B-cell populations, with viral RNA also present in the monocyte-macrophage fraction of two of these. HCV-RNA-negative stranded molecules, indicative of the viral multiplication, were significantly increased in cells maintained in cultures with PHA/PMA stimulation. The results indicate that HCV infect blood mononuclear cells, thus suggesting that this cellular tropism may play a role in HCV infection.

The cytokine secretion profiles of T cell lines (TCL) specific for purified protein derivative (PPD) or streptokinase (SK), contemporarily derived from nine atopic and nine nonatopic individuals, were compared. Upon stimulation with phorbol myristate acetate (PMA) plus anti-CD3 monoclonal antibody (mAb), all TCL from both atopics and nonatopics produced interleukin (IL)-2 and interferon (IFN)-gamma. The mean IL-2 production by PPD- or SK-specific TCL from both atopics and nonatopics was similar, whereas the mean IFN-gamma production by TCL derived from atopics was significantly lower. In addition, both PPD- and SK-specific TCL from atopics produced detectable amounts of IL-4 and IL-5, whereas the corresponding TCL derived from nonatopics did not. A total number of 107 and 99 PPD-specific CD4+ T cell clones (TCC) were then derived from TCL of 4 atopic and 4 nonatopic donors and assessed for their profile of cytokine production in response to stimulation with either PMA plus anti-CD3 mAb or the specific antigen. Under both these experimental conditions, virtually all PPD-specific TCC from both atopic and nonatopic individuals produced IL-2 and IFN-gamma. In contrast, the great majority of PPD-specific TCC derived from nonatopic individuals did not produce IL-4 and IL-5, whereas high proportions of PPD-specific TCC derived from atopic donors displayed the ability to produce noticeable amounts of IL-4 and IL-5 besides IL-2 and IFN-gamma. These data indicate that CD4+ T cells from atopic individuals are able to produce IL-4 and IL-5 in response to bacterial antigens, such as PPD and SK, that usually evoke responses with a restricted type-1 T helper (Th1)-like cytokine profile in nonatopic individuals. Aberrant IL-4 production by Th cells may represent one of the immune alterations responsible for enhanced IgE antibody production in atopic people.

Publisher Summary Despite the great progress that has been achieved in recent years in the diagnosis and treatment of Hodgkin's lymphoma, the etiopathogenesis of this disease still remains obscure. Definite proof that Hodgkin's disease (HD) is a malignant neoplasm, albeit a remarkably atypical one, has been provided during the past two decades by a number of cytogenetic, immunological, and molecular biology studies. Several fundamental issues, however, still remain open. They include the genesis of the immune deficiency, the nature of the normal counterpart of the neoplastic cells, and the role of other tumor-infiltrating lymphocytes. This chapter describes the immunological alterations found in untreated HD patients, mainly focusing on those involving the T and B cell compartments. The chapter also discusses the hypotheses on the origin of Reed–Sternberg (RS) cells and describes the role of the cells surrounding them in involved lymphoid organs.

Human bone marrow (BM) cells lacking T- and B-cell markers expressed RNA encoding interleukin (IL) 4 and secreted detectable amounts of IL-4 in supernatants in response to Fc epsilon or Fc gamma receptor (Fc epsilon R or Fc gamma R) cross-linking. In some experiments, IL-5 RNA expression in response to Fc epsilon R cross-linkage could also be detected. In contrast, RNA transcripts for, and secretion of, IL-2, IL-6, and interferon gamma were never observed. The presence of IL-3 in the cultures was essential for IL-4 production by non-B, non-T BM cells in response to Fc gamma R cross-linking and enhanced IL-4 RNA expression in response to Fc epsilon R cross-linking. Under the same experimental conditions, BM T and B lymphocytes, as well as peripheral blood T, B, and non-B, non-T cells, did not express IL-4 RNA. Prolonged incubation of non-B, non-T cells in IgE-free medium followed by extensive washing did not inhibit IL-4 production induced by anti-IgE antibodies, suggesting that the Fc epsilon R involved in the response has the characteristics of a high-affinity receptor. The Fc epsilon R+ cells were separated from the Fc epsilon R- cells by sorting non-B, non-T BM cell suspensions with fluorescein isothiocyanate-conjugated IgE and then assessed for both IL-4 RNA expression and alcian blue staining. Both IL-4-producing and alcian blue-positive cells segregated with the Fc epsilon R+ fraction. These data suggest that human BM cells, probably belonging to the mast cell and/or basophil lineage, are capable of producing IL-4 in response to Fc epsilon R or Fc gamma R cross-linkage.

A total number of 119 (98 CD 4+ and 21 CD 8+) T cell clones were established from tonsil and peripheral blood of three nonallergic individuals and examined for their ability to induce in vitro IgE synthesis in normal B cells. Following preactivation for 24 h with phytohemagglutinin, 34 clones (33 CD4+ and 1 CD 8+) induced normal B cells to synthesize remarkable amounts of IgE in vitro. In contrast, equal numbers of T blasts of phytohemagglutinin-induced T cell lines obtained from unfractionated T lymphocyte suspensions of the same donors did not show such an effect. The in vitro IgE synthesis evoked by T cell clones was detectable between day 6 and 9 and peaked on day 12. Most clones maintained their ability to stimulate in vitro IgE synthesis in repeated assays over a 3-month period. The induction of IgE synthesis by cloned T cells did not reflect alloantigen recognition on target B cells, since T cell clones induced IgE synthesis in B cells from all randomly selected donors tested, including autologous B cells. Preincubation for 24 h with optimal stimulatory concentrations of anti-CD 3 (OKT 3) monoclonal antibody or its addition through the entire culture period also enabled T cell clones to stimulate de novo IgE synthesis in vitro in normal B cells. Virtually all the T cell clones active on IgE synthesis induced the in vitro production of remarkable amounts of IgM and IgG as well. These data indicate that several human T cell clones can induce normal B cells to synthesize immunoglobulin of different classes, including IgE, regardless of alloantigen recognition on target B cells or specificity for peculiar antigens. The activity of these clones was apparently mediated by triggering of the monomorphic molecular complex CD 3, immediately before or during the incubation of T cell clones with the target B cells.

Circulating T cells from four patients with the hyper-IgE syndrome were found to produce significantly lower concentrations of interferon-gamma (IFN-gamma) in response to stimulation with phytohemagglutinin (PHA) than did T cells from eight age-matched healthy controls, three patients with atopic dermatitis and one patient with chronic granulomatous disease. A clonal analysis revealed that patients with hyper-IgE syndrome had markedly lower proportions of circulating T cells able to produce IFN-gamma and tumor necrosis factor-alpha (TNF-alpha) in comparison with controls. In contrast, the proportions of peripheral blood T cells able to produce IL-4 or IL-2 were not significantly different in patients and controls. All the four patients with hyper-IgE syndrome showed high proportions of circulating CD4+ helper T cells able to induce IgE synthesis in allogeneic B cells, as well. Such an activity for IgE synthesis appeared to be positively correlated with IL-4 production by T cells and inversely related to the ability of the same T cells to produce IFN-gamma. Since IFN-gamma exerts an inhibitory effect on the synthesis of IgE and both IFN-gamma and TNF-alpha play an important role in inflammatory reactions, we suggest that the defective production of IFN-gamma may be responsible for hyperproduction of IgE and the combined defect of IFN-gamma and TNF-alpha may contribute to the undue susceptibility to infections seen in patients with hyper-IgE syndrome.

Studies of human IgE synthesis are summarized and provide further insight into the cellular and molecular mechanisms involved in IgE regulation, as well as in the alterations responsible for IgE disregulation in some pathological conditions. These include the demonstration that IL-4 is the essential factor for the induction of human IgE syntheses. Another T cell-derived lymphokine, IFN-gamma negatively regulated the IgE synthesis induced by IL-4. These two lymphokines can be produced by different T helper cells, as shown in mice, but they can also be the product of the same T cells clones. Additional cellular and/or molecular signals appear to be involved in the IL-4-induced IgE synthesis, but their precise role in this process is undetermined. Finally, alternations of one or more of these regulatory mechanisms can be detected in patients with pathological conditions characterized by hyperproduction of IgE. In particular, the increased prevalence of T cells clones able to produce IL-4 appears to be a distinctive feature of patients with common atopy whereas a reduction in the proportion of IFN-gamma-producing T cells seems to be peculiar of both patients with hyper-IgE syndrome and patients with AIDS.

T Lymphocytes from thyroid infiltrates and peripheral blood (PB) of 3 patients with Hashimoto's thyroiditis (HT) were cloned using a microculture system previously shown to allow the clonal expansion of virtually all PB T lymphocytes from normal individuals. The phenotypic and functional features of a total number of 153 clones from thyroid infiltrates and 206 clones from PB were examined and compared with those of 272 clones derived from normal PB and spleens. The majority of clones derived from thyroid infiltrates of patients with HT had the cytotoxic/suppressor (T8+) phenotype, whereas the majority of clones from PB expressed the helper/inducer (T4+) phenotype. In addition, a consistent proportion (25%) of clones derived from PB of one patient had a phenotype (T3+T4-T8-) that was only occasionally found on clones obtained from PB or spleens of normal subjects. Most clones derived from both PB and thyroid infiltrates of the patients with HT had cytolytic activity, assessed by a lectin-dependent cytolytic assay against the murine P815 tumor cell line. The high frequency of cytotoxic T cells in thyroid infiltrates was related to the increased proportion of T8+ cells, whereas enhanced percentages of cytotoxic cell precursors with T4+ and T3+T4-T8- phenotypes primarily accounted for the high frequency of cytolytic T cells in the PB of the same patients. Many cytolytic T cell clones derived from thyroid infiltrates also had natural killer activity against human K562 and MOLT-4 target cells. These data provide the first functional analysis of T lymphocytes infiltrating the thyroid gland in patients with HT and suggest that the high proportions of cytolytic T cell precursors found in both thyroid infiltrates and PB of these patients may be of importance in determining the tissue damage in thyroid autoimmune disease.

Levels of IgE protein and IgE antibodies specific for 8 different allergenic extracts were measured in the serum of a large series of patients infected by the human immunodeficiency virus (HIV) and in HIV-seronegative subjects belonging to the same risk groups (intravenous drug-users, homosexual men and hemophiliacs). The proportion of subjects showing elevated IgE levels was higher among HIV-infected patients with group IV disease than among HIV-infected patients with group II-III diseases or seronegative individuals. In addition, many HIV-infected patients with elevated IgE levels showed the presence in their serum of IgE antibodies specific for fungal antigens.

Purified T lymphocytes (E rosetting cells) isolated from peripheral blood (PB) of four patients with acquired immune deficiency syndrome (AIDS) were cloned under culture conditions (phytohemagglutinin plus interleukin 2) which allow clonal expansion of most T lymphocytes. A total number of 101 T cell clones (37 CD4+ and 64 CD8+) from PB of AIDS patients and of 188 T cell clones (115 CD4+ and 73 CD8+) from PB of four normal controls were obtained and tested for their helper function as well as for their capacity to release lymphokines. Unstimulated CD4+ TCC from patients with AIDS showed enhanced helper function for IgG synthesis in vitro in both autologous and normal allogeneic B cells in comparison to clonable CD4+ T cells of normal donors. Such activity was further potentiated by addition to the cell cultures of anti-CD3 monoclonal antibody. The majority of CD4+ T cell clones from AIDS patients showed a reduced ability to produce interleukin 2 and interferon-gamma in response to activation with phytohemagglutinin. However, most of them released greater amounts of soluble factor(s) able to promote B cell proliferation of anti-IgM-activated normal B cells and to induce the differentiation of normal B lymphocytes into IgG-secreting cells. These data demonstrate that most surviving CD4+ T cells in PB of patients with AIDS belong to a T cell subset producing B cell growth and differentiation factors, which may contribute to the B cell hyperactivation seen in AIDS patients.

The IgE helper function of human T cell clones or their phytohemagglutinin-induced supernatants was positively correlated with their ability to produce or their content in interleukin 4 (IL-4), whereas it was inversely correlated with production of or content in gamma interferon. The addition to B cell cultures of anti-IL-4 antibody abolished not only the IgE synthesis induced by recombinant human IL-4, but also that induced by IL-4-producing T cell clones or their phytohemagglutinin-induced supernatants. A clonal analysis in non-atopic donors and patients with common atopy showed that atopies possess in their peripheral blood significantly higher numbers of T cells able to secrete IL-4 and to provide helper function for IgE.

Purified T lymphocytes (E rosetting cells) isolated from the involved lymphoid organs (lymph nodes and spleen) of five patients with Hodgkin's disease (HD) were cloned under culture conditions (phytohemagglutinin plus interleukin-2) that allow clonal expansion of most T lymphocytes. A total number of 104 CD4+ T cell clones so obtained were tested for their ability to proliferate in response to autologous mitomycin-treated non-T cells. About half of these clones but none of 234 CD4+ T cell clones derived from normal lymphoid tissues or peripheral blood displayed a proliferative response to autologous stimulators. When clones proliferating in autologous mixed lymphocyte reaction (AMLR) were assessed for their ability to respond in allogeneic MLR (allo-MLR), most of them were found to exhibit consistent proliferation in response to more than one haplotype. Both the AMLR and the allo-MLR by HD clones were inhibited by adding monoclonal antibodies (MoAbs) reactive with monomorphic determinants of major histocompatibility complex (MHC) class II (DR) antigens to the cultures, whereas MoAbs reactive with MHC class I antigens were without effect. These studies suggest that lymphoid organs involved by HD contain high proportions of CD4 T cells showing abnormal recognition of DR antigens. These unusual cells may play an important role in the pathogenetic mechanisms occurring in HD.

A large panel of phytohemagglutinin (PHA)-induced T cell clones (690 in total), established from four different human lymphoid tissues (peripheral blood, tonsils, lymph nodes and spleens) by a high-efficiency cloning technique, was characterized according to their pattern of lymphokine production. The majority of both CD4+ and CD8+clones from all lymphoid tissues produced interleukin (IL) 2 and/or interferon (1FN)-γ response to 24-h stimulation with PHA. In contrast, higher proportions of IL4-producing clones were found among CD4+clones from tonsils and spleens than from peripheral blood and lymph nodes, whereas only a minority of CD8+ clones from all lymphoid tissues were found to produce IL4. It was not possible to divide the CD4+ (helper/inducer) clones on the basis of their pattern of lymphokine activity into two clear-cut groups analogous to Thl and Th2 helper clones described in mice. Although 21 out of 503 (4%) CD4+ T cell clones produced IL4, but not IFN-γ or IL2, and 208 (41%) produced IL2 and/or IFN-γ, but not IL4, a total number of 185 (37%) CD4+ clones showed the ability to produce IL4 plus IL2 and/or IFN-γ. All types of CD4+ T cells (as classified according to their pattern of lymphokine activity) provided help for IgG production in allogeneic B cells. In contrast, helper function for IgE was detectable only among the IL4-producing clones. However, the proportion of CD4+ clones providing help for IgE synthesis was significantly lower among those producing IL4 and IFN-γ or IL4, IL2 and IFN-γ than among those producing IL4 alone or IL4 and IL2. Thus, a clear-cut dichotomy between IL4- and IFN-γ-producing Th cells, as found in mice, does not seem to exist in humans. However, IL4 and IFN-γ, even if not always produced by distinct T cell subsets, appear to regulate reciprocally the synthesis of IgE in humans as well.

Supernatants (SN) from 10 phytohemagglutinin (PHA)-stimulated human T cell clones (TCC), selected for their helper function on IgE synthesis, were found to provide IgE helper activity in atopic B cells showing low or undetectable spontaneous in vitro IgE synthesis. In contrast, SN from 5 PHA-stimulated TCC unable to provide helper function for IgE synthesis consistently failed to elicit IgE production. SN active on IgE synthesis contained high concentrations of interleukin-4 (IL-4), whereas inactive SN did not contain detectable amounts of IL-4. Moreover, the IgE helper activity of TCC SN was strongly inhibited by the addition of interferon-gamma (IFN-gamma) to B cell cultures. These data suggest that IL-4 may play a role in the induction of in vitro human IgE synthesis, whereas IFN-gamma displays an inhibitory effect.

T-lymphocyte populations isolated from spleens of untreated patients with Hodgkin's disease (HD) were grown by combining limiting dilution techniques and an assay system that allows clonal proliferation of virtually all human T cells. Under these conditions, high proportions of splenic T lymphocytes (50-80%) underwent clonal expansion, so that the set of clones obtained could be considered representative of the starting T-cell population. A total number of 229 clones from 6 HD spleens (3 uninvolved and 3 histologically involved by the disease) and 133 clones from 3 control spleens (obtained from otherwise healthy individuals, who underwent post-traumatic splenectomy) were examined for surface markers and tested in functional assays. One hundred and seventy-five clones from HD spleens and 75 clones from control spleens expressed the "helper/inducer" (T3+ T4+ T8-)phenotype, whereas as 54 clones from HD spleens and 58 control clones expressed the "cytotoxic/suppressor" (T3+T4-T8+) phenotype. As assessed by a non-specific lectin-dependent lytic assay, the proportion of HD clones displaying cytolytic activity was higher than that of cytolytic clones derived from control spleens. The majority of T4+ clones obtained from HD spleens (either uninvolved or histologically involved by the disease) were cytolytic, whereas only a small proportion (less than 10%) of T4+ clones derived from normal peripheral blood or spleens displayed cytolytic activity. The cytolytic potential of T4+ clones obtained from HD spleens did not reflect the activity of natural killer (NK) cells, since a minority of these clones exerted NK activity on K562 target cells. In addition, most of the T4+ cytolytic clones derived from HD spleens produced particularly high amounts of interleukin-2 (IL-2). These data indicate that T lymphocytes which concentrate in spleens of patients with HD consist at least in part of an infrequent T4+ cell subset co-expressing cytolytic activity and production of IL-2. These cells may reflect a cytotoxic reaction against unknown antigens associated with self class-II histocompatibility antigens.

A total of 76 T-cell clones established from peripheral blood (PB) of 2 patients with the acquired immune deficiency syndrome (AIDS) and of 141 T-cell clones established from PB of 3 normal donors were compared for their ability to produce interleukin 2 (IL-2) and gamma-interferon (gamma-IFN). Twenty-seven clones from AIDS patients and 85 clones from controls expressed the CD4 phenotype, whereas 49 clones from AIDS patients and 56 clones from controls expressed the CD8 phenotype. There were no significant differences in the proportions of IL-2-producing CD4 T-cell clones established from PB of patients with AIDS and controls, but the mean concentration of IL-2 produced by CD4 clones from AIDS patients was significantly lower than that produced by CD4 clones from controls. Both the proportion of gamma-IFN-producing CD4 clones and the mean concentration of gamma-IFN produced by CD4 clones were significantly lower in AIDS patients than in controls. In contrast, there were no differences between AIDS patients and normal individuals in the proportion of IL-2- or gamma-IFN-producing CD8 clones, or in the mean concentration of IL-2 and gamma-IFN produced by CD8 clones. These data suggest that the reduced ability of PB T-cells from patients with AIDS to produce IL-2 and gamma-IFN is not simply due to altered proportions or numbers of T-cell subpopulations, but also reflects intrinsic abnormalities of individual CD4 T lymphocytes.

The role of T cells and monocytes, as well as that of cytokines, such as IL-1, IL-2 and IL-6, on the IL-4-dependent in vitro human IgE synthesis was investigated. Recombinant IL-4, IL-4-containing T-cell clone supernatants and different combinations of recombinant cytokines failed to induce highly purified B cells to synthesize IgE. IL-4-dependent IgE synthesis was restored by addition to purified B cells of either untreated or mitomycin C-treated autologous T lymphocytes. Addition to purified B cells of autologous monocytes did not restore the IgE response, but usually it exerted a potentiating effect on the synthesis of IgE induced by IL-4 in the presence of suboptimal concentrations of T cells. The activity of T cells apparently preceded that of IL-4 and required a physical contact with B cells. The presence in culture of IL-2 also appeared to be necessary for the T-cell and IL-4-dependent IgE synthesis. Even though not essential, IL-6 was able to potentiate IgE synthesis in most experiments, whereas IL-1 did not display any modulatory effect.