The utility of the ISAC allergen array in the investigation of idiopathic anaphylaxis.

A diagnosis of idiopathic anaphylaxis following a detailed clinical assessment remains very challenging for patients and clinicians. Risk reduction strategies such as allergen avoidance are not possible. This study investigated whether the (ISAC) allergen array with 103 allergens would add diagnostic value in patients with idiopathic anaphylaxis. We extended the specific immunoglobulin (Ig)E testing in 110 patients with a diagnosis of idiopathic anaphylaxis from five UK specialist centres using ISAC arrays. These were divided into three groups: score I identified no new allergen sensitization beyond those known by previous assessment, score II identified new sensitizations which were not thought likely to explain the anaphylaxis and score III identified new sensitizations felt to have a high likelihood of being responsible for the anaphylaxis. A proportion (50%) of score III patients underwent clinical reassessment to substantiate the link to anaphylaxis in this group. The results show that 20% of the arrays were classified as score III with a high likelihood of identifying the cause of the anaphylaxis. A wide range of major allergens were identified, the most frequent being omega-5-gliadin and shrimp, together accounting for 45% of the previously unrecognized sensitizations. The ISAC array contributed to the diagnosis in 20% of patients with idiopathic anaphylaxis. It may offer additional information where a careful allergy history and follow-on testing have not revealed the cause of the anaphylaxis.

A UK national audit of hereditary and acquired angioedema.

Hereditary angioedema (HAE) and acquired angioedema (AAE) are rare life-threatening conditions caused by deficiency of C1 inhibitor (C1INH). Both are characterized by recurrent unpredictable episodes of mucosal swelling involving three main areas: the skin, gastrointestinal tract and larynx. Swelling in the gastrointestinal tract results in abdominal pain and vomiting, while swelling in the larynx may be fatal. There are limited UK data on these patients to help improve practice and understand more clearly the burden of disease. An audit tool was designed, informed by the published UK consensus document and clinical practice, and sent to clinicians involved in the care of HAE patients through a number of national organizations. Data sets on 376 patients were received from 14 centres in England, Scotland and Wales. There were 55 deaths from HAE in 33 families, emphasizing the potentially lethal nature of this disease. These data also show that there is a significant diagnostic delay of on average 10 years for type I HAE, 18 years for type II HAE and 5 years for AAE. For HAE the average annual frequency of swellings per patient affecting the periphery was eight, abdomen 5 and airway 0·5, with wide individual variation. The impact on quality of life was rated as moderate or severe by 37% of adult patients. The audit has helped to define the burden of disease in the UK and has aided planning new treatments for UK patients.

Immediate hypersensitivity to chlorhexidine is increasingly recognised in the United Kingdom.

BACKGROUND: Chlorhexidine is widely used as an antiseptic agent. It is a potentially allergenic substance that can cause severe hypersensitivity reactions. OBJECTIVE: We describe six patients who had anaphylactic reactions attributed to chlorhexidine during surgery. These patients were exposed to chlorhexidine in gels, swabs and catheters. MATERIALS AND METHODS: Six patients from three UK centres with clinical history suggestive of anaphylaxis during surgery are reported. Detailed history, review of case notes, determination of chlorhexidine specific IgE, mast cell tryptase and skin tests were performed. RESULTS: On detailed assessment five of six patients demonstrated a previous history of reactions on re-exposure to chlorhexidine. All six patients had elevated specific IgE to chlorhexidine. Skin prick test with chlorhexidine was performed in four of the six patients and was found to be positive. CONCLUSION: Immediate hypersensitivity to chlorhexidine appears to be common but underreported in the UK. We recommend that centres investigating patients with reactions during anaesthesia and surgery should routinely include testing for chlorhexidine allergy.

Human T cells cannot act as autonomous antigen-presenting cells, but induce tolerance in antigen-specific and alloreactive responder cells.

The ability of two HLA-DR-expressing human T cell clones to function as antigen-presenting cells (APC) was investigated using highly purified T cells. The results demonstrated that these T cell clones are unable to act as autonomous APC, and that recognition of nominal or alloantigens on the surface of T cells leads to a state of nonresponsiveness. The first observation was that a T cell clone with specificity for the 306-324 peptide of influenza hemagglutinin (HA), and raised from a DR1 responder, exhibited apparent degeneracy of major histocompatibility complex restriction when cultured with peptide in the presence of peripheral blood mononuclear cells (PBMC) expressing a wide variety of structurally unrelated DR types. However, when the PBMC were pulsed with peptide and washed before coculture with the clone, peptide was exclusively recognized with DR1Dw1. This implied that in the presence of soluble peptide the T cells were displaying ligand to each other, and that the third-party APC were providing costimulatory signals. To test the ability of T cells to act as autonomous APC, accessory cell-free preparations of two DR1-restricted clones were cultured with peptide in the presence or the absence of added B cell APC. T cell purity was established by the absence of proliferation in response to the mitogen phytohemagglutinin (PHA). PHA-nonresponsive T cells were completely unable to proliferate in response to peptide alone; furthermore, preculture of the HA-specific clone, in the complete absence of accessory cells, with the same concentration of peptide (1 microgram/ml) that induced optimal proliferation when presented by conventional APC, led to profound nonresponsiveness. The same phenomenon was also observed when two of three anti-DR1 alloreactive T cell clones were precultured with a DR1-expressing T cell clone. The ability of the DR1-expressing clone to induce nonresponsiveness in anti-DR1 clones correlated with recognition of the DR1 alloantigen on the DR1-expressing clone.

An approach to the patient with urticaria.

Patients with urticaria make up a large proportion of the referrals to allergy clinics. There are many causes of urticaria and it is the clinical history which is most important when attempting to identify potential causes; however, urticaria is very often idiopathic. In a small minority of patients urticaria may be a symptom of a serious underlying medical illness or the allergic symptoms may progress to cause systemic reactions, and it is important to identify these patients and to remember that severe urticaria is a distressing and disabling condition. This review will discuss classification, investigation and treatment of urticaria and will consider some of the more unusual types of urticaria that may be encountered in the out-patient clinic.

A rapid limiting dilution assay for measuring frequencies of alloreactive, interleukin-2-producing T cells in humans.

A limiting dilution analysis (LDA) has been established which measures the total numbers of alloreactive interleukin-2 (IL-2)-secreting T cells in human peripheral blood mononuclear cells (PBMC). A significant advantage over most previous LDA is that the assay may be completed in approximately 48 h since an IL-2-dependent 'indicator' cell line is used to reduce assay time. Results are reproducible and correlate with the degree of HLA class II antigenic disparity between responder and stimulator cells. Use of both PBMC and Epstein-Barr virus-transformed B lymphoblastoid cell lines (B-LCL) as stimulator cells permits estimation of the frequency of Epstein-Barr virus-specific T cells in different responder individuals. A modification of the assay may also be used to measure the frequencies of 'primed' alloreactive cells, i.e., those alloreactive cells which have previously encountered their specific stimulating alloantigen. Use of the assay in the clinical context of bone marrow and renal transplantation is discussed.

Positive correlation of T cell sensitization with frequencies of alloreactive T helper cells in chronic renal failure patients.

Chronic renal failure patients are often "sensitized" to foreign alloantigens following renal transplantation or blood transfusion. B cell sensitization is assessed by measuring the reactivity of cytotoxic antibodies in the patient's serum against a panel of allogeneic cells (panel-reactive antibodies, [PRA]). However, this technique provides no information about T cell allosensitization. T cell allosensitization may be important since T cells play a central role in allograft rejection and since "primed" alloreactive cells--i.e., T cells that have previously encountered their specific alloantigen, are relatively resistant to immunosuppression. In order to detect T cell sensitization we used a limiting dilution analysis assay, which measured both total and primed frequencies of alloreactive T helper (Th) cells. Total alloreactive Th cell frequencies were generally high. Primed alloreactive Th cell frequencies could be detected in all patients studied, although there was considerable variation in frequencies between different patients. Frequencies of primed Th cells did not correlate with levels of PRA. However, in all three of the patients who had received DR-mismatched kidneys, and who had subsequently rejected these grafts rapidly, high primed frequencies were detected against the mismatched DR antigens. This was not the case for two patients who had lost their grafts two or more years after transplantation.

Comparison of helper and cytotoxic antirecipient T cell frequencies in unrelated bone marrow transplantation.

Donor/recipient histocompatibility antigen differences initiate acute graft-versus-host disease (GVHD) after bone marrow transplantation. Frequency analysis, using limiting dilution techniques, of functionally defined (helper or cytotoxic) antirecipient T lymphocyte precursors in the peripheral blood of the donor has been shown to be an accurate predictor for the development of moderate-to-severe acute GVHD. Here, we describe a sensitive assay for measuring alloreactive helper (IL-2-producing) T lymphocyte precursor (HTLp) frequencies, and compare the ability of this assay and the cytotoxic T lymphocyte precursor (CTLp) assay to detect HLA- class II and class I differences and to predict clinical outcome in a cohort of unrelated donor/recipient BMT pairs. Twenty-two pairs underwent unrelated donor BMT. Patients with high (> 1:100 x 10(3)) HTLp or CTLp frequencies had a higher incidence of moderate-to-severe (grades II-IV) acute GVHD (80% and 100%, respectively) than pairs with low (< 1:100 x 10(3)) frequencies (40% and 57%, respectively). Ten (45%) patients have died, but all patients with both a low HTLp and low CTLp frequency remain alive. The HTLp and CTLp assays provided similar predictive information for outcome. Given that the HTLp assay is more rapid and less labor intensive, it offers an additional or alternative functional method for donor selection in unrelated donor BMT.

Evidence that umbilical cord blood contains a higher frequency of HLA class II-specific alloreactive T cells than adult peripheral blood. A limiting dilution analysis.

Umbilical cord blood has been used to effect hematological reconstitution and there are sufficient stem cells available in the cord blood obtainable from a single placenta to reconstitute an adult patient. Umbilical cord blood might therefore, have widespread potential use in the field of bone marrow transplantation. We compared alloreactivity of paired samples of adult and cord peripheral blood mononuclear cells, by measuring frequencies of both alloreactive T helper cells and cytotoxic T cell precursors (CTLp), using limiting dilution analysis. In addition we compared the phenotype of adult and neonatal PBMC, using monoclonal antibody staining. Cord PBMC in general showed higher frequencies of alloreactive Th than adult PBMC, with statistically significant differences in 6 out of 10 experiments. There was no statistically significant difference between adult and cord CTLp frequencies. Adult and cord PBMC surface phenotype was similar, except that cord blood contained fewer lymphocyte function-associated-3 (LFA-3) positive (memory) cells.

Peptide recognition by T-cell clones of an HLA-DRB1*1501/*0901 heterozygous donor is promiscuous only between parental alleles.

The HLA class II isotype and allelic restrictions of peptide recognition were analyzed with T cells from a DRB1*1501/DRB1*0901 heterozygous donor. Nineteen T cell clones, all directed against the single mycobacterial epitope p21-40 were tested with HLA homozygous lymphoblastoid cell lines as antigen-presenting cells. The most striking finding has been, that several DR isotype restricted clones recognized the peptide in the context of both parental, but not of unrelated alleles. In contrast, DQ and DP restricted clones responded in the context of one parental allele only. Most DR promiscuous clones produced interferon-gamma but not IL-4, whereas most DQ and DP clones produced IL-4. We postulate that the confinement of DR promiscuity only to the parental alleles was established possibly during thymic maturation of T cells and that the proportions between monogamous and promiscuous T cells may play a role in the MHC mediated influences on host resistance to infections and other immune responses.

Normal complement C4 values do not exclude hereditary angioedema.

This report describes a patient with hereditary angioedema (HAE) in whom complement C4 values were consistently normal. There was a family history of HAE, for which the patient had previously been screened, but in view of her normal C4 values she was deemed unaffected. However, at 10 years of age she presented with an eight month history of episodes of swelling affecting her hands and recurrent episodes of abdominal pain over the previous few months. In view of the recent clinical history of swellings and the family history of HAE, C4 and C1 inhibitor (C1inh) were measured. The C4 concentration was found to be within the normal range but the C1inh value was low (0.07 g/litre; normal range, 0.18-0.37). The patient was started on tranexamic acid and at an outpatient review three months later her episodes of swelling were occurring less often and were less severe. Although recent papers have suggested that the diagnosis of HAE can be excluded if complement C4 concentrations are normal, this case highlights the fact that C4 concentrations can be normal in this condition, and it is recommended that both C4 and C1inh concentrations should be measured to exclude HAE.

Atypical C-ANCA following high dose intravenous immunoglobulin.

AIMS: (1) To assess a range of intravenous immunoglobulin products for atypical classical antineutrophil cytoplasmic antibody (C-ANCA) staining and to determine if this is present in patients treated with high dose intravenous immunoglobulin (2 g/kg/month) and replacement doses (200 mg/kg fortnightly); (2) using the United Kingdom national external quality assessment scheme (NEQAS), to determine if laboratories could differentiate this pattern from classical ANCA. METHODS: ANCA testing was performed on 30 batches of intravenous immunoglobulin from several manufacturers. Six patients treated with high dose intravenous immunoglobulin and 11 receiving replacement doses of immunoglobulin for hypogammaglobulinaemia were tested for ANCA by indirect immunofluorescence on cytospin preparations of ethanol fixed neutrophils and by enzyme linked immunosorbent assay (ELISA). One of the positive immunoglobulin batches was tested blindly by 125 laboratories involved in NEQAS by indirect immunofluorescence and by ELISA in some laboratories. RESULTS: 16 of 31 batches of intravenous immunoglobulin from six different manufacturers were atypical C-ANCA positive. Three of six patients receiving high dose intravenous immunoglobulin and none of 11 patients on replacement doses were atypical C-ANCA positive. The results of the NEQAS assessment by indirect immunofluorescence were 68% C-ANCA positive, 17% negative, 9% atypical C-ANCA, and 6% P-ANCA. CONCLUSIONS: Some but not all intravenous immunoglobulin products yield a positive atypical cANCA by indirect immunofluorescence. An identical pattern may be observed in patients receiving high dose intravenous immunoglobulin but not in those on replacement doses. Of laboratories participating in NEQAS, 68% reported this pattern as cANCA. This reinforces the importance of reporting only "classical ANCA," defined by international ANCA workshops, to maintain the specificity of ANCA immunofluorescence and its close disease associations.

Allergy to local anaesthetic: the importance of thorough investigation.

A case report is presented which highlights the importance of a good history in arriving at the correct diagnosis in cases where allergy to local anaesthetic is suspected. Management of the patient is discussed and the topic of 'adverse reaction' briefly reviewed.

Heat retention using passive systems during anaesthesia: comparison of two plastic wraps, one with reflective properties.

Hypothermia during prolonged surgery may be prevented by active and passive warming methods. We have compared randomly two types of occlusive body wraps in groups of 20 patients. One wrap had additional reflective properties which, by reducing radiative in addition to convective and evaporative heat loss, was expected to improve heat conservation. Patients were studied during hepatopancreatobiliary surgery and both groups were similar in characteristics. Skin and core body temperatures increased and core temperature exceeded 37 degrees C in 40% of patients in both groups. This continuous increase in temperature was unexpected and the observed heat gain may have been stimulated endogenously by the type of surgery rather than that supplied externally. Overall, mean hourly heat gain was similar in both groups: 71 (SD 28) kJ h-1 in the reflective group and 67 (33) kJ h-1 in the other group.

A case of synchronous bilateral separate primary male breast carcinomas.

Breast carcinoma in the male is uncommon, but to find a case of bilateral synchronous primary separate carcinomas is extremely rare. We report on the management of such a case, illustrating current concepts in therapy. This case highlights the fact that, as in the female, bilateral breast carcinomas can occur in the male and the attending surgeon should remain vigilant at all times when treating unilateral disease.

The role of adherence in determining the site of infection by Corynebacterium diphtheriae.

Twenty-nine strains of Corynebacterium diphtheriae isolated from throats and 29 strains from skin lesions, the latter mainly from communities of low socio-economic status in tropics and cold climates, have been examined for the property of adherence to human buccal epithelial cells. All throat strains showed adherence. In contrast, strains from skin lesions were predominantly poor adherers. These results indicate that strains of C. diptheriae from throats must now be added to the important group of pathogens which possess the property of adherence to surface epithelial cells of mucous membranes, thus providing an essential first step in the process of colonizing their hosts. The possible role of this phenomenon of adherence to bucco-pharyngeal epithelial cells in the evolution of the host-parasite relationship of C. diphtheriae is discussed.

Patient-controlled sedation for cataract surgery using peribulbar block.

Patients undergoing cataract surgery using peribulbar block were allocated randomly to self-administer doses of either midazolam 0.1 mg or propofol 3.3 mg without a lock-out facility; in the control group the syringe was charged with saline, not as a placebo, but to "blind" the surgeon and the nurse observer. For midazolam and propofol, median doses were 2.54 (0.1-6.0) mg and 87.4 (0-145) mg, respectively. Patient-controlled sedation significantly reduced the level of anxiety, with median visual analogue anxiety scores in the midazolam, propofol and saline groups of 5 (0-38) mm, 5 (0-25) mm and 15 (0-92) mm, respectively (P < 0.05). Some patients did not administer the sedative when available while others in the saline group would have benefited from anxiolytic drugs. While both drugs prevented an increase in heart rate, only midazolam prevented an increase in arterial pressure during surgery.

The effects of theophylline and salbutamol on right and left ventricular function in chronic bronchitis and emphysema.

We have compared the effects of oral theophylline and salbutamol on right and left ventricular function in twelve patients with chronic bronchitis and emphysema. Right and left ventricular ejection fraction (RVEF and LVEF) were measured using multiple gated radionuclide ventriculography. Theophylline 600 mg and salbutamol 4 mg both produced increases in RVEF and LVEF. There were no significant changes in blood gases after either drug. The clinical significance of the effects of oral bronchodilators on cardiac function in patients with chronic bronchitis and emphysema has yet to be determined.