Low end-tidal CO2 as a real-time severity marker of intra-anaesthetic acute hypersensitivity reactions.

BACKGROUND: Prompt diagnosis of intra-anaesthetic acute hypersensitivity reactions (AHR) is challenging because of the possible absence and/or difficulty in detecting the usual clinical signs and because of the higher prevalence of alternative diagnoses. Delayed epinephrine administration during AHR, because of incorrect/delayed diagnosis, can be associated with poor prognosis. Low end-tidal CO2 (etCO2) is known to be linked to low cardiac output. Yet, its clinical utility during suspected intra-anaesthetic AHR is not well documented. METHODS: Clinical data from the 86 patients of the Neutrophil Activation in Systemic Anaphylaxis (NASA) multicentre study were analysed. Consenting patients with clinical signs consistent with intra-anaesthetic AHR to a neuromuscular blocking agent were included. Severe AHR was defined as a Grade 3-4 of the Ring and Messmer classification. Causes of AHR were explored following recommended guidelines. RESULTS: Among the 86 patients, 50% had severe AHR and 69% had a confirmed/suspected IgE-mediated event. Occurrence and minimum values of arterial hypotension, hypocapnia and hypoxaemia increased significantly with the severity of AHR. Low etCO2 was the only factor able to distinguish mild [median 3.5 (3.2;3.9) kPa] from severe AHR [median 2.4 (1.6;3.0) kPa], without overlap in inter-quartile range values, with an area under the receiver operator characteristic curve of 0.92 [95% confidence interval: 0.79-1.00]. Among the 41% of patients who received epinephrine, only half received it as first-line therapy despite international guidelines. CONCLUSIONS: An etCO2 value below 2.6 kPa (20 mm Hg) could be useful for prompt diagnosis of severe intra-anaesthetic AHR, and could facilitate early treatment with titrated doses of epinephrine. CLINICAL TRIAL REGISTRATION: NCT01637220.

The importance of EN ISO 15189 accreditation of allergen-specific IgE determination for reliable in vitro allergy diagnosis.

BACKGROUND: Allergen-specific serum immunoglobulin E detection and quantification have become an important step in allergy diagnosis and follow-up. In line with the current trend of laboratory test accreditation to international standards, we set out to design and assess an accreditation procedure for allergen-specific serum IgE. METHODS: Method validation according to the accreditation procedure under the EN ISO 15189 standard was carried out for allergen-specific immunoglobulin E determination using the fluoroimmunoenzymatic method ImmunoCAP(®) (ThermoFisher). Data were produced by 25 hospital laboratories in France. A total of 29 allergen specificities including mixes, extracts, and molecular allergens were assayed. Allergen-specific serum immunoglobulin E concentrations ranged from 0.1 to 100 kUA /l. RESULTS: Repeatability, reproducibility, and accuracy results fulfilled method validation criteria for automated laboratory tests and proved similar irrespective of the allergen specificity, allergen-specific serum immunoglobulin E concentration, or individual laboratory. CONCLUSION: Allergen-specific serum immunoglobulin E determination with the fluoroimmunoenzymatic method ImmunoCAP(®) is a highly repeatable, reproducible, and accurate method which may be considered as a single analyte assay in view of the EN ISO 15189 accreditation procedure.

[Biomarkers and functional tests in immediate hypersensitivity to SARS-CoV-2 mRNA vaccines]. / Biomarqueurs et tests fonctionnels dans l'hypersensibilité immédiate aux vaccins ARNm dirigés contre le SARS-CoV-2.

Hypersensitivity to mRNA vaccines directed against SARS-CoV-2 are rare. They may be related to an IgE-dependent mechanism involving PEG contained in vaccines in the form of liposomes. Direct activation of the classical complement pathway (CARPA) has also been strongly suspected. In addition to skin tests, biomarkers have been proposed: anti-PEG antibodies, determination of anaphylatoxins C5a and C3a, or soluble complex C5b-9. Anti-PEG antibodies can be measured by non-standardized in house methods; their presence in post-vaccination reactions against SARS-CoV2 has not been confirmed by all the studies as well as for complement proteins. Mast cell mediators (histamine and tryptase) could rarely be assayed at the time of reaction and their increase is inconstant depending on studies. A slightly elevated baseline tryptase level in some patients suggests that hyper-alphatryptasemia might be involved. A basophil activation test (BAT) can be performed but the results are still preliminary depending on the allergens used: PEG, PEG in the form of liposomes or vaccine itself. The lack of positivity of skin tests in some patients even though basophils are able to be activated in the presence of the same allergen confirms the hypothesis in this case of a possible non-IgE-dependent phenomenon. In conclusion, concerning the exploration of immediate reactions to mRNA vaccines directed against SARS-CoV-2, the place of biological markers requires additional studies in order to better identify the actors and mechanisms involved.

Passive transient transfer of peanut allergy by liver transplantation.

We report a case of transient symptomatic transferred IgE-mediated peanut allergy after elective blood-group compatible liver transplantation. We show that the allergy was transient and therefore passive, authorizing further uneventful peanut consumption. Skin tests with commercial peanut extract and native peanut were performed in the recipient. Circulating specific IgE against peanut and recombinant peanut allergens (rArah1, rArah2, rArah3) was measured in stored serum samples collected from the recipient between 6 months before and 8 months after liver transplantation. Specific IgE levels in the donor were measured at the time of multiorgan donation. In the recipient, diagnosis of IgE-mediated peanut anaphylaxis was based on the clinical history and detection of specific IgE against peanut and recombinant major peanut allergens (rArah1, rArah2 and rArah3). Skin tests were negative and specific IgE undetectable 6 months after the clinical reaction. Oral peanut challenge was negative excluding persistent peanut allergy. This case confirms that IgE-mediated peanut allergy can be transferred by liver transplantation and shows that it may be transient and therefore passively acquired.

Anaphylactic reaction after methylene blue-treated plasma transfusion.

Methylene blue-treated fresh-frozen plasma (MB-FFP) is mainly used in Europe. The advantage of the methylene blue system is that units can be treated individually. The combined action of methylene blue and illumination is a photodynamic process preventing viral RNA and DNA replication. We report the first immediate allergic hypersensitivity reaction to methylene blue-treated plasma transfusion. The clinical course and subsequent assessment of the allergic reaction, including skin tests and basophil activation test, confirmed methylene blue-induced IgE-mediated anaphylaxis. All immediate reactions after MB-FFP transfusion should be investigated to document the underlying mechanism.

Place of human amniotic membrane immunoblotting in the diagnosis of autoimmune bullous dermatoses.

BACKGROUND: Fine analysis of antiskin autoantibodies can contribute to the differential diagnosis of autoimmune bullous dermatoses. OBJECTIVES: To develop a high-performance immunoblotting method using human amniotic membrane as the antigen source, and to compare it with current laboratory methods. METHODS: Sera from 113 patients were tested by immunoblotting (IB), rat and monkey oesophagus and salt-split skin indirect immunofluorescence (IIF), and enzyme-linked immunosorbent assay (ELISA) quantification of anti-BP180-NC16a and anti-BP230, or antidesmoglein (Dsg) 1 and 3 antibodies. There were 56 cases of bullous pemphigoid (BP), 22 cases of mucous membrane pemphigoid (MMP), eight cases of epidermolysis bullosa acquisita (EBA), two cases of bullous systemic lupus erythematosus (BSLE), 17 cases of pemphigus vulgaris (PV), and four cases each of pemphigus foliaceus (PF) and paraneoplastic pemphigus (PNP). RESULTS: In BP, the three methods had similar sensitivity (84-89%) for both anti-BP180-NC16a and anti-BP230 antibody detection. In MMP, autoantibodies (mainly directed against BP180 or laminin 332 subunits) were detected in 77% of patients by IB, compared with only 9% by IIF on rat and monkey oesophagus and 36% on salt-split skin, and 14% by anti-BP180-NC16a and anti-BP230 ELISA. In patients with pemphigus, ELISA had 92% sensitivity for anti-Dsg1 and 3, but IB and rat bladder IIF were necessary to confirm PNP by revealing specific and rare patterns (antidesmoplakin I/II, antienvoplakin and antiperiplakin antibodies). IB also revealed anticollagen VII antibodies in 60% of patients with EBA and BSLE, and antibodies to BP180, BP230 and Dsg3 in a few patients who were negative using the other two techniques. CONCLUSION: Amniotic membrane immunoblotting is an interesting diagnostic tool for bullous diseases, as the entire panel of autoantibodies can be detected with a single extract. This method improves the identification of complex and heterogeneous autoimmune processes in conjunction with IIF and ELISA, and is particularly useful for MMP characterization.

Characterization of the immune response in the synovitis, acne, pustulosis, hyperostosis, osteitis (SAPHO) syndrome.

OBJECTIVE: The aetiology of SAPHO (synovitis, acne, palmoplantar pustulosis, hyperostosis, osteitis) syndrome seems to involve genetic, infectious and immunological components. We examined innate and adaptive immune responses in SAPHO syndrome, as compared with PsA and RA. We also studied the effect of etanercept on immunological parameters. METHODS: We studied 29 patients with SAPHO syndrome, as well as 22 patients with RA, 21 patients with PsA and 15 healthy controls. Adaptive immune responses were investigated by assaying total serum immunoglobulins and several autoantibodies. Innate immunity was studied by quantifying blood PMN functions and plasma cytokine levels. PMN responses to Propionibacterium acnes were tested ex vivo. Eight patients who received etanercept for refractory rheumatic disorders were tested before and after 28 days of treatment. RESULTS: SAPHO syndrome was associated with elevated IL-8 and IL-18 plasma levels. IL-8 and TNF-alpha production by purified PMN was higher in the three patient groups than in the healthy controls, but the oxidative burst and IL-18 production were normal. No autoantibodies were detected in SAPHO patients. Induction of PMN IL-8 and TNF-alpha production by P. acnes was impaired in the SAPHO group as compared with the RA and PsA groups. After 28 days of etanercept therapy, PMN IL-8 and TNF-alpha production was down-regulated and TNF-alpha plasma levels were increased. CONCLUSIONS: These results support the view that the SAPHO syndrome may be triggered by an infectious state involving P. acnes, contributing to the strong humoral and cellular pro-inflammatory responses. Etanercept modulation of PMN activation status emphasizes these new immunological findings.

[Unexplained recurrent early miscarriages: Role of immunomodulation?] / Fausses couches précoces récurrentes inexpliquées : quelle est la place de l'immunomodulation ?

About 1-3% of women experience early recurrent miscarriages, defined by ≥3 fetal loss before 14 weeks of gestation. About half of these recurrent early miscarriages could be related to a genetic cause. Pre-implantation genetic diagnosis is used in several European countries, but it is still prohibited in France except for couples at risk for transmission of severe genetic diseases. The immune dysregulation, and in particular allo-immune excessive response, could be responsible for fetal loss in remaining cases, although currently we lack biomarker to confirm the immune-mediated fetal loss. Several immunosuppressive and immunomodulatory treatments have been the subject of small studies in patients with early recurrent miscarriages. The available data do not allow to define the treatment recommendations in this topic, and further studies are necessary.

[Correlation between the presence of type-2 anti-pemphigoid antibodies and dementia in elderly subjects with no clinical signs of pemphigoid]. / Corrélation entre présence d'anticorps anti-antigène de type 2 de la pemphigoïde et démence chez les sujets âgés sans manifestation clinique de pemphigoïde.

BACKGROUND: Pemphigoid is a form of auto-immune bullous dermatosis characterised by the production of antibodies directed against components of hemidesmosomes in the basal membrane. The physiopathological process responsible for unmasking of these antigens is unknown. Pemphigoid is more common in elderly subjects and is most often seen in debilitated subjects. The prevalence of pemphigoid anti-pemphigoid antibodies (anti-PB) is not known in the elderly population presenting no dermatological signs evocative of the disease. We studied the prevalence of anti-PBAg2 antibodies in elderly subjects with no signs of pemphigoid as well as in the correlation between the presence of these antibodies and diagnosis of dementia. PATIENTS AND METHODS: Elderly subjects (aged over 69 years) with no signs of pemphigoid were recruited consecutively in dermatology and geriatrics departments (138 subjects). Details of concomitant medication were recorded for all subjects and clinical examination was performed with calculation of MMS (Mini Mental Score). The subjects were then divided into two groups based on MMS score. The first group comprised subjects without dementia (MMS > 24) while the second comprised subjects with dementia. Serum anti-PBAg2 antibodies were determined by ELISA and indirect immunofluorescence with confirmation by Western blot. Antinuclear antibodies, used as a control for non-specific immune response, were assayed in all serum samples. The prevalence of these antibodies was compared between the two groups. RESULTS: The two groups were comparable in terms of age, sex and presence of dermatological diseases (ulcers, bedsores, erysipelas). Each group comprised 69 subjects. The overall presence of anti-PBAg2 antibodies in subjects with no signs are suggestive of pemphigoid was 3.6%. Presence of anti-PBAg2 antibodies was associated with diagnosis of dementia (p=0.04; 0% and 7% in groups 1 and 2, respectively). No correlation was seen between the presence of anti-PBAg2 antibodies and concomitant medication or dermatological disease. The overall prevalence of antinuclear antibodies was 14.5% and the figure was similar between the two groups. DISCUSSION: The presence of anti-PBAg2 could be associated with the diagnosis of dementia in elderly subjects.

[Association between the presence of antiphospholipid antibodies and the occurrence of autism spectrum disorder in childhood]. / Lien entre trouble du spectre autistique de l'enfant et anticorps antiphospholipides : une étude cas-témoin.

OBJECTIVES: To evaluate the association between the presence of antiphospholipid (APL) antibodies and the occurrence of autism spectrum disorder (ASD) in childhood. METHODS: A prospective, monocentric case-control study from February 2012 to August 2014 comparing the APL antibodies of children with ASD (group 1) and children without ASD (group 2). RESULTS: Group 1 consisted of 44 children with ASD defined by clinical, genetic, metabolic, and morphological criteria. Group 2 consisted of 26 control children without ASD. One of children with ASD (2.3 %) had persistent anticardiolipin (ACL) antibodies, five of them (11.4 %) had persistent APL antibodies, one of them (2.3 %) had antiannexin V (AAV) antibodies, and two of them (4.5 %) had antiphosphatidylethanolamine (APE) antibodies. Two of the control children (7.7 %) had persistent APL antibodies. None of them had persistent ACL, AAV, or APE antibodies. Comparing group 1 and 2 children, no significant difference was found between the presence and the titers of conventional and non conventional antibodies (P<0.05). Furthermore, one mother of an autistic child (3 %) had persistent APL antibodies. CONCLUSION: ASD had no significant relation with the presence of APL antibodies.

Second generation anti-cyclic citrullinated peptide (anti-CCP2) antibodies can replace other anti-filaggrin antibodies and improve rheumatoid arthritis diagnosis.

We compared the diagnostic performance of anti-cyclic citrullinated peptide antibodies detected with second-generation enzyme immunoassay (anti-CCP2) with that of IgM-rheumatoid factor (RF), anti-perinuclear factor (APF), and anti-keratin antibodies (AKA). The sensitivity of anti-CCP2 was better than that of APF and AKA: they were detected in 25% rheumatoid arthritis (RA) patients without detectable APF or AKA. Their specificity, evaluated in other inflammatory rheumatic disease, was similar to that of APF and AKA. Despite the lower specificity, IgM-RF in combination with anti-CCP2 is interesting, as they do not completely overlap. Anti-CCP2 antibody detection seems to be a good alternative to other anti-filaggrin antibodies in the diagnosis of RA.

Anti-oxidized low-density-lipoprotein (OxLDL) antibodies in systemic lupus erythematosus with and without antiphospholipid syndrome.

The aim of this study was to examine potential links between antiOxLDL antibodies and the clinical and biological features of secondary antiphospholipid syndrome (II APLS) associated with systemic lupus erythematosus (SLE). A cohort study was done of 98 SLE patients followed-up for 1 y, including 18 with definite II APLS and 13 patients with definite primary APLS (I APLS). IgG anticardiolipin, IgG anti beta2 GPI, lupus anticoagulant, VDRL and IgG antiOxLDL were measured in all 98 study subjects. High antiOxLDL titers were found in seven (39%) of the 18 patients with II APLS vs 10 (12.5%) of the 80 patients without APLS (P < 0.01; OR = 4.45; 95% CI = 1.4-14.1) and none of the 13 patients with I APLS (P < 0.02). The mean antiOxLDL titer was not significantly higher in the SLE patients with than without II APLS (P > 0.05). A high antiOxLDL titer was correlated with deep venous thrombosis (P < 0.01; OR = 5.77; 95% CI = 0.54-61) but not with arterial thrombosis (P > 0.05; OR = 1; 95% CI = 0.29-3.09), thrombocytopenia, central nervous system involvement, livedo reticularis, or a positive Coombs test. The antiOxLDL antibody titer was correlated with the IgG anticardiolipin antibody titer (r = 0.235; P = 0.02) and with the IgG anti-beta2 GPI antibody titer (r = 0.224; P = 0.026). AntiOxLDL elevation was found in 17% of SLE patients and was significantly associated with II APLS and venous thrombosis. We found no evidence suggesting that antiOxLDL may be associated with atherosclerosis.

Anticitrullinated protein/peptide antibody assays in early rheumatoid arthritis for predicting five year radiographic damage.

OBJECTIVE: To study the value of antibodies to citrullinated proteins/peptides for predicting joint outcomes in patients with recent onset rheumatoid arthritis (RA). METHODS: 191 patients with RA onset within the past year were followed up prospectively for five years. Serum samples obtained from 145 patients at baseline before disease modifying antirheumatic drug treatment were examined using three anticitrullinated protein/peptide antibody assays: antiperinuclear factor (APF) by indirect immunofluorescence (IIF), antikeratin antibodies (AKA) by IIF, and anti-cyclic citrullinated peptide (CCP) antibodies by enzyme linked immunosorbent assay (ELISA). Radiographs of the hands and feet taken at baseline and after three and five years were evaluated using Sharp scores modified by van der Heijde. RESULTS: Anti-CCP ELISA was positive in 58.9% of patients. APF/anti-CCP agreement was 77%. The likelihood of a total Sharp score increase after five years was significantly greater among patients with anti-CCP antibodies (67%; odds ratio (OR) 2.5; 95% confidence interval (95% CI) 1.2 to 5.0) or APF (57%; OR 2.4; 95% CI 1.2 to 4.9) but not rheumatoid factor (RF; OR 0.7; 95% CI 0.3 to 1.5). Mean values for radiographic damage, erosion, and joint narrowing scores at the three times were significantly higher in patients with anti-CCP or APF than in those without. AKA did not significantly predict radiographic damage. In separate analyses of patients with and without RF, anti-CCP or APF was better than RF for predicting total joint damage and joint damage progression after five years. CONCLUSION: Antibodies to citrullinated proteins/peptides determined early in the course of RA by APF IIF or anti-CCP ELISA are good predictors of radiographic joint damage. Further studies of clinical, laboratory, and genetic parameters are needed to improve RA outcome prediction in clinical practice.