Investigating the Human Intestinal DNA Virome and Predicting Disease-Associated Virus-Host Interactions in Severe Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS).

Understanding how the human virome, and which of its constituents, contributes to health or disease states is reliant on obtaining comprehensive virome profiles. By combining DNA viromes from isolated virus-like particles (VLPs) and whole metagenomes from the same faecal sample of a small cohort of healthy individuals and patients with severe myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS), we have obtained a more inclusive profile of the human intestinal DNA virome. Key features are the identification of a core virome comprising tailed phages of the class Caudoviricetes, and a greater diversity of DNA viruses including extracellular phages and integrated prophages. Using an in silico approach, we predicted interactions between members of the Anaerotruncus genus and unique viruses present in ME/CFS microbiomes. This study therefore provides a framework and rationale for studies of larger cohorts of patients to further investigate disease-associated interactions between the intestinal virome and the bacteriome.

Investigating Antibody Reactivity to the Intestinal Microbiome in Severe Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS): A Feasibility Study.

Myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) is a multisystemic disease of unknown aetiology that is characterised by disabling chronic fatigue and involves both the immune and gastrointestinal (GI) systems. Patients display alterations in GI microbiome with a significant proportion experiencing GI discomfort and pain and elevated blood biomarkers for altered intestinal permeability compared with healthy individuals. To investigate a possible GI origin of ME/CFS we designed a feasibility study to test the hypothesis that ME/CFS pathogenesis is a consequence of increased intestinal permeability that results in microbial translocation and a breakdown in immune tolerance leading to generation of antibodies reactive to indigenous intestinal microbes. Secretory immunoglobulin (Ig) A and serum IgG levels and reactivity to intestinal microbes were assessed in five pairs of severe ME/CFS patients and matched same-household healthy controls. For profiling serum IgG, we developed IgG-Seq which combines flow-cytometry based bacterial cell sorting and metagenomics to detect mucosal IgG reactivity to the microbiome. We uncovered evidence for immune dysfunction in severe ME/CFS patients that was characterised by reduced capacity and reactivity of serum IgG to stool microbes, irrespective of their source. This study provides the rationale for additional studies in larger cohorts of ME/CFS patients to further explore immune-microbiome interactions.

The first reported cases of meat allergy following tick bites in the UK.

Allergic reactions frequently involve the production of immunoglobulin E (IgE) antibodies to proteins. However, reactions directed against carbohydrate moieties are increasingly being recognised. Tick bites can contribute to the development of immunoglobulin E to the galactose-1,3-galactose (alpha-gal) moiety on tick salivary proteins. These IgE molecules can cross-react with alpha-gal found in red meats, causing Type I IgE-mediated hypersensitivity reactions to these foods. We present three cases of delayed reactions to beef, pork and lamb in patients with prior tick bites and in the presence of a positive-specific IgE to alpha-gal. Patients were advised to avoid red meat consumption and to carry emergency treatment in the form of anti-histamines with or without adrenaline autoinjector devices. This is the first published report of red meat allergy caused by tick bites suffered in the UK.

The presence of overlapping quality of life symptoms in primary antibody deficiency (PAD) and chronic fatigue syndrome (CFS).

BACKGROUND: Fatigue, sleep disturbance and altered mood are frequently reported in patients with primary antibody deficiency syndrome (PADS) on adequate immunoglobulin replacement therapy. This study aimed to determine the frequency of symptoms compatible with chronic fatigue syndrome (CFS) in patients with PADS. METHODS: The study involved the distribution of 682 self-completed postal questionnaires to ascertain the presence and frequency of symptoms compatible with CFS in patients with PADS. The reporting of symptoms for each patient were scored against the CFS diagnostic criteria used within our own South London Chronic Fatigue service. RESULTS: The frequency of symptoms compatible with CFS were evident in 26 of the 188 patients (16.25%) returning adequately completed questionnaires. We considered a bias in the return of questionnaires amongst PADS patients with fatigue to be likely. As such we estimated the minimum frequency of CFS in patients with PADS to be 4% based on the 682 PAD patients to whom the questionnaire was distributed. This was significantly higher than the 0.5% estimate of the prevalence of CFS in the community in western populations. While the presence of significant fatigue correlated with the presence of anxiety and depression, there was no association with self-reported lung damage. Sleep disturbance affected 60% of the PAD patients returning satisfactory questionnaires and as expected the CFS score was higher in those with greater physical limitation. CONCLUSIONS: We conclude that patients with PADS have a high frequency of fatigue, low mood and anxiety. We suggest routine questioning for the symptoms of fatigue, disturbed sleep and altered mood in patients with PADS. The use of several treatment strategies in CFS may prove beneficial in improving the quality of life of patients with PAD.

Risks and management of antiepileptic drug induced skin reactions in the adult out-patient setting.

Adverse cutaneous reactions caused by mostly aromatic antiepileptic drugs (AED) affect 50.000 people a year in the United Kingdom (UK; incidence 75.7/100.000). Optimal management of these cases is often difficult, as the patient may report symptoms to a general practitioner, attend Accident & Emergency or inform a specialist over the telephone or via email. When clinical assessment is limited it is thought safest to withdraw offending medication and inform the patient of a new drug allergy. This may unjustifiably restrict future treatment choices, and increase cost. Most frequent offenders are aromatic AEDs: carbamazepine, oxcarbazepine, eslicarbazepine, phenytoin, lamotrigine, phenobarbitone, primidone (recently licensed lacosamide associated with lower risk) and the sulpha-derivative zonisamide. Our study provides a summary of severe delayed allergic reactions and offers a pragmatic management pathway for patients suffering a suspected drug-induced rash. We include UK pretreatment screening guidelines, step by step clinical assessment of rash and associated symptoms aiding early identification of patients at risk of developing severe allergic reactions. At the same time our manuscript reviews published data informing best choice and titration of alternative medication when allergy confirmed. Finally we summarize current knowledge on genetic predisposition and other personalized risks of AED allergies identifying gaps in our current understanding.

Stress, pseudoallergens, autoimmunity, infection and inflammation in chronic spontaneous urticaria.

Chronic spontaneous urticaria (CSU) is often associated with organ specific autoimmunity but is rarely caused by food allergy. Colourings and preservatives in pre-packaged foods, so called pseudoallergens, have also been implicated. Factors that promote inflammation or reduce anti-inflammatory mechanisms may however, predispose susceptible individuals to CSU. Chronic underlying infection and mental and emotional stress can sometimes precede the onset of CSU and once established can exacerbate the symptoms. There is early evidence of dysbiosis within the gastrointestinal tract in people with CSU and reduced levels of vitamin D are also evident. The latter may be related to the importance of vitamin D3 in increasing T regulatory function which can control a tendency to autoimmunity. It is quite possible that a state of on-going chronic inflammation with reduced anti-oxidant mechanisms may underlie the not infrequent association between CSU and metabolic syndrome. Effective treatment of CSU should involve the use of anti-histamines, intermittent steroids and anti-IgE therapy. For recalcitrant disease immune modulatory therapy has a place. However, talking therapies that reduce stress and anxiety, vitamin D3 supplementation, correction of intestinal dysbiosis and treatment of any chronic infection should also be considered.

CD24 Expression and B Cell Maturation Shows a Novel Link With Energy Metabolism: Potential Implications for Patients With Myalgic Encephalomyelitis/Chronic Fatigue Syndrome.

CD24 expression on pro-B cells plays a role in B cell selection and development in the bone marrow. We previously detected higher CD24 expression and frequency within IgD+ naïve and memory B cells in patients with Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS) compared with age-matched healthy controls (HC). Here, we investigated the relationship between CD24 expression and B cell maturation. In vitro stimulation of isolated B cells in response to conventional agonists were used to follow the dynamics of CD24 positivity during proliferation and differentiation (or maturation). The relationship between CD24 expression to cycles of proliferation and metabolism in purified B cells from HC was also investigated using phospho-flow (phosphorylation of AMPK-pAMPK), 1proton nuclear magnetic resonance and Mitotracker Far-red (Mitochondrial mass-MM). In vitro, in the absence of stimulation, there was an increased percentage of CD24+ viable B cells in ME/CFS patients compared to HC (p < 0.05) following 5 days culture. Following stimulation with B cell agonists, percentage of CD24+B cells in both naïve and memory B cell populations decreased. P < 0.01). There was a negative relationship between percentage of CD24+B cells with MM (R2 = 0.76; p < 0.01), which was subsequently lost over sequential cycles of proliferation. There was a significant correlation between CD24 expression on B cells and the usage of glucose and secretion of lactate in vitro. Short term ligation of the B cell receptor with anti-IgM antibody significantly reduced the viability of CD24+ memory B cells compared to those cross-linked by anti-IgD or anti-IgG antibody. A clear difference was found between naïve and memory B cells with respect to CD24 expression and pAMPK, most notably a strong positive association in IgD+IgM+ memory B cells. In vitro findings confirmed dysregulation of CD24-expressing B cells from ME/CFS patients previously suggested by immunophenotype studies of B cells from peripheral blood. CD24-negative B cells underwent productive proliferation whereas CD24+ B cells were either unresponsive or susceptible to cell death upon BCR-engagement alone. We suggest that CD24 expression may reflect variations in energy metabolism on different B cell subsets.

Elevated Levels of Serum Vascular Endothelial Growth Factor-A Are Not Related to NK Cell Parameters in Recurrent IVF Failure.

BACKGROUND: Vascular Endothelial Growth Factor and NK cells have an interrelated role in angiogenesis that is critical for placentation and success of in vitro fertilization. An attempt was made to assess a possible relationship between the two in this study. METHODS: A case control study was performed comparing the serum levels of VEGF-A and its receptor VEGF-R1 with levels of NK cells, activated NK cells and NK cytotoxicity in 62 women with Repeated Implantation Failure (RIF). The healthy control group consisted of 72 women of similar age, without known issues in achieving pregnancy or evidence of autoimmunity. Levels of VEGF-A and VEGF-R1 were quantified by ELISA methods with standard curve interpolation. NK cell subsets were determined with flow cytometry using fluorescent-tagged anti-CD56, anti-CD16, anti-CD3 and anti-CD69. NK cytotoxicity was performed by incubating peripheral blood mononuclear cells and K562 cultured cells with propidium iodide, steroid, intralipid and intravenous immunoglobulin, using previously described methods. Statistical analysis involved Mann-Whitney-U and Spearman's rank correlation testing with p-values defined as <0.05. RESULTS: It was found that VEGF-A levels were significantly raised in women with RIF compared to healthy controls (362.9 vs. 171.6 pg/ml, p<0.0001), with no difference in VEGF-R1 levels between groups (1499 vs. 1202 pg/ml, p=0.4082). There was no correlation between VEGF-A or VEGF-R1 and the absolute levels of circulating NK cells, CD69 activated NK cells or NK cytotoxicity. CONCLUSION: The absence of correlation between VEGF-A or VEGF-R1 and NK cells suggests VEGF secretion and regulation is independent of NK cell activity in RIF.

Beer, Cider, and Wine Allergy.

Background. Allergy to beer is often due to specific proteins in barley and sometimes to lipid transfer protein. Allergy to wine is frequently due to a sensitivity to grape proteins. We present a rare case of allergy to beer, wine, and cider resulting from IgE reactivity to yeasts and moulds which also explained the patient's additional sensitivity to yeast extracts and blue cheese. Case Presentation. The patient's symptoms included throat and facial itching accompanied by mild wheeze and severe urticaria. Diagnosis of allergy to yeast was confirmed by specific IgE testing as well as that to relevant foods and beverages. The patient's ongoing management included advice to avoid beer, wine, and other food groups containing specific yeasts, in addition to carrying a short acting nonsedating antihistamine as well as an adrenaline autoinjector. Conclusions. Cases of yeast allergy are extremely rare in medical literature but may be underrecognised and should be considered in patients presenting with reactions to alcoholic beverages and other yeast-containing products.

Chronic fatigue syndrome and the immune system: Where are we now?

Myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) is characterised by multiple symptoms including fatigue, headaches and cognitive impairment, which have a significantly adverse effect on the normal functioning and well-being of the individual. These symptoms are often triggered or worsened following physical or mental exertion. ME/CFS has long been thought of as having a significant immunological component, but reports describing changes in immune function are often inconsistent between study groups. Although the wide range of physical, neurocognitive and autonomic symptoms reported have seriously hampered attempts to understand pathophysiological pathways, investment in biomedical research in ME/CFS is finally increasing with a number of novel and promising investigations being published. The onset of ME/CFS may often be linked to (viral) infections which would be consistent with a variety of alterations in natural killer (NK) cell function as described by a number of different groups. Consistency in cytokine data has been lacking so far, although recently more sophisticated approaches have led to more robust data from large patient cohorts. New hope has also been given to sufferers with the possibility that therapies that deplete B cells can result in clinical improvement. To understand the pathogenic mechanism in this complex condition, it is important to consider repeated analysis in different cohorts. In this review, we will discuss the potential of different components of the immune system to be involved in the pathogenesis of ME/CFS.

Investigating unexplained fatigue in general practice with a particular focus on CFS/ME.

Unexplained fatigue is not infrequent in the community. It presents a number of challenges to the primary care physician and particularly if the clinical examination and routine investigations are normal. However, while fatigue is a feature of many common illnesses, it is the main problem in Chronic Fatigue Syndrome/Myalgic Encephalomyelitis (CFS/ME). This is a poorly understood condition that is accompanied by several additional symptoms which suggest a subtle multisystem dysfunction. Not infrequently it is complicated by sleep disturbance and alterations in attention, memory and mood.Specialised services for the diagnosis and management of CFS/ME are markedly deficient in the UK and indeed in virtually all countries around the world. However, unexplained fatigue and CFS/ME may be confidently diagnosed on the basis of specific clinical criteria combined with the normality of routine blood tests. The latter include those that assess inflammation, autoimmunity, endocrine dysfunction and gluten sensitivity. Early diagnosis and intervention in general practice will do much to reduce patient anxiety, encourage improvement and prevent expensive unnecessary investigations.There is presently an on-going debate as to the precise criteria that best confirms CFS/ME to the exclusion of other medical and psychiatric/psychological causes of chronic fatigue. There is also some disagreement as to best means of investigating and managing this very challenging condition. Uncertainty here can contribute to patient stress which in some individuals can perpetuate and aggravate symptoms. A simple clinical scoring system and a short list of routine investigations should help discriminate CFS/ME from other causes of continued fatigue.

Does the Maternal Serum IgG Level during Pregnancy in Primary Antibody Deficiency Influence the IgG Level in the Newborn?

Purpose. To find out if the serum IgG level in the newborn baby was affected by low maternal serum IgG during pregnancy in two newly diagnosed primary antibody deficient patients. Method. Infant cord blood IgG level was compared with maternal IgG level in 2 mothers with newly diagnosed primary antibody deficiency, who declined replacement IgG treatment during pregnancy. Results. Both mothers delivered healthy babies with normal IgG levels at birth. Conclusions. The normal IgG levels and sound health in these 2 babies in spite of low maternal IgG throughout pregnancy raise interesting discussion points about maternofoetal immunoglobulin transport mechanisms in primary antibody deficiency.

IgG4- related disease as a rare cause of tubulointerstitial nephritis.

Isolated IgG4 tubulointerstitial nephritis (TIN) is a rare disorder characterized by raised serum IgG4 levels and histological findings of dense lymphoplasmacytic infiltrates rich in IgG4 positive plasma cells. We report a case of isolated IgG4 TIN that presented with acute kidney injury in an 84 year old man with a polyclonal increase in his total IgG and a raised IgE of 381 kUA/L but without evidence of systemic autoimmunity. We draw a parallel with IgG4-related autoimmune pancreatitis and show raised levels of circulating regulatory T cells. Importantly the plasma levels of the T regulatory cell cytokine, IL10, the TH1 cytokines IL12 and IFNγ, the proinflammatory TNF α and immune regulatory IL27 were all highly raised. Furthermore, the level of IL21 that promotes IgG4 production was also very significantly elevated. These results suggest efforts of the immune system to reduce inflammation and suppress an exaggerated Th2 response. A raised serum IgG in the setting of acute kidney injury and in the absence of autoimmunity and chronic infection should encourage an assessment of the IgG subclasses. Prompt steroid treatment of those with a raised IgG4 may reduce ongoing renal damage.

Psychosocial factors involved in memory and cognitive failures in people with myalgic encephalomyelitis/chronic fatigue syndrome.

BACKGROUND: Myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) is characterized by persistent emotional, mental, and physical fatigue accompanied by a range of neurological, autonomic, neuroendocrine, immune, and sleep problems. Research has shown that psychosocial factors such as anxiety and depression as well as the symptoms of the illness, have a significant impact on the quality of life of people with ME/CFS. In addition, individuals may suffer from deficits in memory and concentration. This study set out to explore the relationships between variables which have been found to contribute to cognitive performance, as measured by prospective and retrospective memory, and cognitive failures. METHODS: Eighty-seven people with ME/CFS answered questionnaires measuring fatigue, depression, anxiety, social support, and general self-efficacy. These were used in a correlational design (multiple regression) to predict cognitive function (self-ratings on prospective and retrospective memory), and cognitive failures. RESULTS: Our study found that fatigue, depression, and general self-efficacy were directly associated with cognitive failures and retrospective (but not prospective) memory. CONCLUSION: Although it was not possible in this study to determine the cause of the deficits, the literature in this area leads us to suggest that although the pathophysiological mechanisms of ME/CFS are unclear, abnormalities in the immune system, including proinflammatory cytokines, can lead to significant impairments in cognition. We suggest that fatigue and depression may be a result of the neurobiological effects of ME/CFS and in addition, that the neurobiological effects of the illness may give rise to both fatigue and cognitive deficits independently.

Variably severe systemic allergic reactions after consuming foods with unlabelled lupin flour: a case series.

INTRODUCTION: Lupin allergy remains a significant cause of food-induced allergic reactivity and anaphylaxis. Previous work suggests a strong association with legume allergy and peanut allergy in particular. Both doctors and the public have little awareness of lupin as an allergen. CASE PRESENTATION: Case 1 was a 41-year-old Caucasian woman without previous atopy who developed facial swelling, widespread urticaria with asthma and hypotension within minutes of eating a quiche. Her lupin allergy was confirmed by both blood and skin tests. Her lupin sensitivity was so severe that even the miniscule amount of lupin allergen in the skin testing reagent produced a mild reaction.Case 2 was a 42-year-old mildly atopic Caucasian woman with three episodes of worsening urticaria and asthma symptoms over 6 years occurring after the consumption of foods containing lupin flour. Blood and skin tests were positive for lupin allergy.Case 3 was a 38-year-old Caucasian woman with known oral allergy syndrome who had two reactions associated with urticaria and vomiting after consuming foods containing lupin flour. Skin testing confirmed significant responses to a lupin flour extract and to one of the foods inducing her reaction.Case 4 was a 54-year-old mildly atopic Caucasian woman with a 7 year history of three to four episodes each year of unpredictable oral tingling followed by urticaria after consuming a variety of foods. The most recent episode had been associated with vomiting. She had developed oral tingling with lentil and chickpeas over the previous year. Skin and blood tests confirmed lupin allergy with associated sensitivity to several legumes. CONCLUSIONS: Lupin allergy can occur for the first time in adults without previous atopy or legume sensitivity. Although asymptomatic sensitisation is frequent, clinical reactivity can vary in severity from severe anaphylaxis to urticaria and vomiting. Lupin allergy may be confirmed by skin and specific immunoglobulin E estimation. Even skin testing can cause symptoms in some highly sensitive individuals. The diagnosis of lupin allergy in adults may be difficult because it is frequently included as an undeclared ingredient. Better food labelling and medical awareness of lupin as a cause of serious allergic reactions is suggested.

Maternal serum cytokines at 30-33 weeks in the prediction of preeclampsia.

OBJECTIVE: The aim of this case-control study at 30-33 weeks, a few days or weeks before the clinical onset of preeclampsia (PE), was to assess whether serum concentrations of cytokines differ between patients who are destined to develop PE and those with uncomplicated pregnancies. METHODS: A panel of cytokines was measured using Luminex technology at 30-33 weeks' gestation in 39 cases that developed PE at or after 34 weeks and 117 unaffected controls. RESULTS: The serum concentrations of most analysed cytokines were no different in women who developed PE than in controls. The proportions of women with detectable concentrations of MIP-1α and IL-8 were significantly lower in those with PE than in the controls (MIP-1α: 14/39 vs 76/117, P = 0.003; IL-8:13/39 vs 83/117, P < 0.0001). The median maternal serum concentration of IL-1ß was significantly lower in the PE cases than in the controls (0.38 pg/mL, range 0.01-0.92, vs 0.60 pg/mL, range 0.02-3.54, P = 0.005). CONCLUSION: Our findings do not lend support to the hypothesis that systemic inflammation precedes the onset of PE or that cytokines are good markers for such inflammation and certainly the panel of cytokines we examined does not provide useful prediction of subsequent development of PE.

Natural killer cells and their activation status in normal pregnancy.

Increased peripheral blood-activated NK cell counts are associated with increased risk of miscarriage and failed in vitro fertilization treatment. However, assessment of activated peripheral NK cells in normal and pathological pregnancies beyond implantation and early miscarriage has not been described. Total CD69 expressing NK cells counts were measured by flow cytometry in healthy women with singleton pregnancies, including 45 at 11(+6)-13(+6) weeks' gestation, 46 at 20(+0)-22(+4) weeks, and 42 at 31(+6)-33(+5) weeks. The number of peripheral blood NK cells decreased, whereas the percentage of activated CD69 expressing NK cells increased from the first to the third trimester of pregnancy. This study shows the course of peripheral blood NK cells and activated CD69 expressing NK cells in uncomplicated nulliparous singleton pregnancies. This is a first step in understanding their implication in pathological pregnancies.

Mechanism of human chorionic gonadotrophin-mediated immunomodulation in pregnancy.

Human chorionic gonadotrophin (hCG) is released within hours of fertilization and has a profound ability to downregulate maternal cellular immunity against trophoblastic paternal antigens. It also promotes angiogenic activity of the extravillous trophoblast, and impairment of this function may lead to inadequate placentation and an increased risk of preeclampsia. There is increasing evidence that hCG alters the activity of dendritic cells via an upregulation of indoleamine 2,3-dioxygenase activity. This reduces T-cell activation and cytokine production, as well as encouraging Treg cell recruitment to the fetal-maternal interface. These changes are critical in promoting maternal tolerance. hCG is also able to increase the proliferation of uterine natural killer cells, while reducing the activity of cytotoxic peripheral blood natural killer cells. There are rare reports of autoantibodies directed against hCG or the luteinizing hormone/hCG receptor in women with recurrent miscarriage. These autoantibodies are more frequent in women with thyroid autoimmunity. This may explain the association between thyroid autoimmunity and impaired fertility. Downregulating these anti-hCG and anti-luteinizing hormone/hCG receptor autoantibodies may be helpful in some women with early miscarriage or recurrent failed in vitro fertilization.

Four infants presenting with severe vomiting in solid food protein-induced enterocolitis syndrome: a case series.

INTRODUCTION: Several different foods have been implicated in inducing the delayed and very significant vomiting and sometimes diarrhea that occurs in food protein-induced enterocolitis syndrome. While immunoglobulin E is not involved, the mechanism(s) that result in the food-induced gastrointestinal symptoms are unclear, although T cell activation has been considered. We report four cases of food protein-induced enterocolitis syndrome caused by different solid foods and without concomitant immunoglobulin E sensitization to milk and soya. Clinical and laboratory evidence of type I immunoglobulin E mediated food reactivity and food-induced T cell activation was absent in each case. CASE PRESENTATIONS: Case 1 concerned a 20-month-old South Asian boy who had experienced four episodes of severe vomiting with flaccidity since four months of age and two hours after consuming rice.Case 2 involved a nine-month-old Caucasian boy who had suffered three episodes of severe vomiting with flaccidity since six months of age and three hours after consuming wheat.The child in Case 3 was a 16-month-old Caucasian boy who had suffered three episodes of severe vomiting with flaccidity since nine months of age and two hours after consuming cod.Case 4 involved a 15-month-old South Asian boy who had suffered three episodes of severe vomiting since eight months of age and two hours after consuming chicken. CONCLUSION: In children with recurrent marked delayed vomiting after the ingestion of specific foods and in whom bronchospasm, skin rash and angioedema are absent, food protein-induced enterocolitis syndrome should be considered. Skin prick testing and specific immunoglobulin E antibodies are negative and the mechanism of the vomiting is unclear. We speculate whether food protein-induced oligoclonal T cell activation may be present. This has similarities to various animal models and improvement may involve deletion of these T cells.