Immunobiodiversity: Conserved and specific immunity across land plants and beyond

Angiosperms represent most plants that humans cultivate, grow, and eat. However, angiosperms are only one of five major land plant lineages. As a whole lineage, plants also include algal groups. All these clades represent a tremendous genetic diversity that can be investigated to reveal the evolutionary history of any given mechanism. In this review, we describe the current model of the plant immune system, discuss its evolution based on the recent literature, and propose future directions for the field. In angiosperms, plant-microbe interactions have been intensively studied, revealing essential cell surface and intracellular immune receptors, as well as metabolic and hormonal defense pathways. Exploring diversity at the genomic and functional levels demonstrates the conservation of these pathways across land plants, some of which are beyond plants. On basis of the conserved mechanisms, lineage-specific variations have occurred, leading to diversified reservoirs of immune mechanisms. In rare cases, this diversity has been harnessed and successfully transferred to other species by integration of wild immune receptors or engineering of novel forms of receptors for improved resistance to pathogens. We propose that exploring further the diversity of immune mechanisms in the whole plant lineage will reveal completely novel sources of resistance to be deployed in crops.

Evolutionary trade-offs at the Arabidopsis WRR4A resistance locus underpin alternate Albugo candida race recognition specificities

The oomycete Albugo candida causes white rust of Brassicaceae, including vegetable and oilseed crops, and wild relatives such as Arabidopsis thaliana. Novel White Rust Resistance (WRR) genes from Arabidopsis enable new insights into plant/parasite co-evolution. WRR4A from Arabidopsis accession Columbia (Col-0) provides resistance to many but not all white rust races, and encodes a nucleotide-binding, leucine-rich repeat immune receptor. Col-0 WRR4A resistance is broken by AcEx1, an isolate of A. candida. We identified an allele of WRR4A in Arabidopsis accession Øystese-0 (Oy-0) and other accessions that confers full resistance to AcEx1. WRR4AOy-0 carries a C-terminal extension required for recognition of AcEx1, but reduces recognition of several effectors recognized by the WRR4ACol-0 allele. WRR4AOy-0 confers full resistance to AcEx1 when expressed in the oilseed crop Camelina sativa.

Genetics of autoimmunity in plants: an evolutionary genetics perspective

Autoimmunity in plants has been found in numerous hybrids as a form of hybrid necrosis and mutant panels. Uncontrolled cell death is a main cellular outcome of autoimmunity, which negatively impacts growth. Its occurrence highlights the vulnerable nature of the plant immune system. Genetic investigation of autoimmunity in hybrid plants revealed that extreme variation in the immune receptor repertoire is a major contributor, reflecting an evolutionary conundrum that plants face in nature. In this review, we discuss natural variation in the plant immune system and its contribution to fitness. The value of autoimmunity genetics lies in its ability to identify combinations of a natural immune receptor and its partner that are predisposed to triggering autoimmunity. The network of immune components for autoimmunity becomes instrumental in revealing mechanistic details of how immune receptors recognize cellular invasion and activate signaling. The list of autoimmunity-risk variants also allows us to infer evolutionary processes contributing to their maintenance in the natural population. Our approach to autoimmunity, which integrates mechanistic understanding and evolutionary genetics, has the potential to serve as a prognosis tool to optimize immunity in crops.

Two unequally redundant "helper" immune receptor families mediate Arabidopsis thaliana intracellular "sensor" immune receptor functions

Plant nucleotide-binding (NB) leucine-rich repeat (LRR) receptor (NLR) proteins function as intracellular immune receptors that perceive the presence of pathogen-derived virulence proteins (effectors) to induce immune responses. The 2 major types of plant NLRs that “sense” pathogen effectors differ in their N-terminal domains: these are Toll/interleukin-1 receptor resistance (TIR) domain-containing NLRs (TNLs) and coiled-coil (CC) domain-containing NLRs (CNLs). In many angiosperms, the RESISTANCE TO POWDERY MILDEW 8 (RPW8)-CC domain containing NLR (RNL) subclass of CNLs is encoded by 2 gene families, ACTIVATED DISEASE RESISTANCE 1 (ADR1) and N REQUIREMENT GENE 1 (NRG1), that act as “helper” NLRs during multiple sensor NLR-mediated immune responses. Despite their important role in sensor NLR-mediated immunity, knowledge of the specific, redundant, and synergistic functions of helper RNLs is limited. We demonstrate that the ADR1 and NRG1 families act in an unequally redundant manner in basal resistance, effector-triggered immunity (ETI) and regulation of defense gene expression. We define RNL redundancy in ETI conferred by some TNLs and in basal resistance against virulent pathogens. We demonstrate that, in Arabidopsis thaliana, the 2 RNL families contribute specific functions in ETI initiated by specific CNLs and TNLs. Time-resolved whole genome expression profiling revealed that RNLs and “classical” CNLs trigger similar transcriptome changes, suggesting that RNLs act like other CNLs to mediate ETI downstream of sensor NLR activation. Together, our genetic data confirm that RNLs contribute to basal resistance, are fully required for TNL signaling, and can also support defense activation during CNL-mediated ETI.

This study shows that two intracellular plant Nod-like immune receptor (NLR-) subfamilies act with unequal redundancy in their roles in plant disease resistance to virulent and avirulent pathogens, in effector-triggered immunity induced gene expression and in immunity-associated cell death. This function is most likely in parallel with, and not downstream of, other canonical intracellular plant immune receptors.

Plant NLRs get by with a little help from their friends

Many plant NLR (nucleotide-binding, leucine-rich repeat) immune receptors require other NLRs for their function. In pairs of chromosomally adjacent sensor/helper NLRs, the sensor typically carries an integrated domain (ID) that mimics the authentic target of a pathogen effector. The RPW8-NLR clade supports the function of many diverse plant NLRs, particularly those with a TIR N-terminal domain, in concert with a family of EP-domain containing signalling partners. The NRC clade of NLRs are required for the function of many unlinked sensor NLRs in Solanaceous plants. We evaluate recent advances in paired NLR biology in the context of the structure and possible mechanisms of the first defined plant inflammasome containing ZAR1.

Diverse NLR immune receptors activate defence via the RPW8-NLR NRG1

Most land plant genomes carry genes that encode RPW8-NLR Resistance (R) proteins. Angiosperms carry two RPW8-NLR subclasses: ADR1 and NRG1. ADR1s act as 'helper' NLRs for multiple TIR- and CC-NLR R proteins in Arabidopsis. In angiosperm families, NRG1 co-occurs with TIR-NLR Resistance (R) genes. We tested whether NRG1 is required for signalling of multiple TIR-NLRs. Using CRISPR mutagenesis, we obtained an nrg1a-nrg1b double mutant in two Arabidopsis accessions, and an nrg1 mutant in Nicotiana benthamiana. These mutants are compromised in signalling of all TIR-NLRs tested, including WRR4A, WRR4B, RPP1, RPP2, RPP4 and the pairs RRS1/RPS4, RRS1B/RPS4B, CHS1/SOC3 and CHS3/CSA1. In Arabidopsis, NRG1 is required for the hypersensitive cell death response (HR) and full oomycete resistance, but not for salicylic acid induction or bacterial resistance. By contrast, nrg1 loss of function does not compromise the CC-NLR R proteins RPS5 and MLA. RPM1 and RPS2 (CC-NLRs) function is slightly compromised in an nrg1 mutant. Thus, NRG1 is required for full TIR-NLR function and contributes to the signalling of some CC-NLRs. Some NRG1-dependent R proteins also signal partially via the NRG1 sister clade, ADR1. We propose that some NLRs signal via NRG1 only, some via ADR1 only and some via both or neither.

Optimization of T-DNA architecture for Cas9-mediated mutagenesis in Arabidopsis

Bacterial CRISPR systems have been widely adopted to create operator-specified site-specific nucleases. Such nuclease action commonly results in loss-of-function alleles, facilitating functional analysis of genes and gene families We conducted a systematic comparison of components and T-DNA architectures for CRISPR-mediated gene editing in Arabidopsis, testing multiple promoters, terminators, sgRNA backbones and Cas9 alleles. We identified a T-DNA architecture that usually results in stable (i.e. homozygous) mutations in the first generation after transformation. Notably, the transcription of sgRNA and Cas9 in head-to-head divergent orientation usually resulted in highly active lines. Our Arabidopsis data may prove useful for optimization of CRISPR methods in other plants.

Cessation of oral anticoagulants in antiphospholipid syndrome

Objective

To study the outcome of patients with antiphospholipid syndrome (APS) after oral anticoagulant treatment cessation.

Methods

We performed a retrospective study of patients with APS experiencing cessation of oral anticoagulant and enrolled in a French multicentre observational cohort between January 2014 and January 2016. The main outcome was the occurrence of recurrent thrombotic event after oral anticoagulation cessation.

Results

Forty four APS patients interrupted oral anticoagulation. The median age was 43 (27–56) years. The median duration of anticoagulation was 21 (9–118) months. Main causes of oral anticoagulant treatment cessation were switch from vitamin K antagonists to aspirin in 15 patients, prolonged disappearance of antiphospholipid antibodies in ten, bleeding complications in nine and a poor therapeutic adherence in six. Eleven (25%) patients developed a recurrent thrombotic event after oral anticoagulation cessation, including three catastrophic APS and one death due to lower limb ischemia. Antihypertensive treatment required at time of oral anticoagulants cessation seems to be an important factor associated with recurrent thrombosis after oral anticoagulant cessation (15.2% in patients with no relapse versus 45.5% in patients with recurrent thrombosis, p = 0.038). Oral anticoagulant treatment was re-started in 18 (40.9%) patients.

Conclusion

The risk of a new thrombotic event in APS patients who stopped their anticoagulation is high, even in those who showed a long lasting disappearance of antiphospholipid antibodies. Except for the presence of treated hypertension, this study did not find a particular clinical or biological phenotype for APS patients who relapsed after anticoagulation cessation. Any stopping of anticoagulant in such patients should be done with caution.

Randomized clinical trial of sacral nerve stimulation for refractory constipation

Background

Open studies have reported favourable results for sacral nerve stimulation in the treatment of refractory constipation. Here, its efficacy was assessed in a double-blind crossover RCT.

Methods

Patients with at least two of the following criteria were included: fewer than three bowel movements per week; straining to evacuate on more than 25 per cent of attempts; or sensation of incomplete evacuation on more than 25 per cent of occasions. Response to therapy was defined as at least three bowel movements per week and/or more than 50 per cent improvement in symptoms. Responders to an initial 3-week peripheral nerve evaluation were offered permanent implantation of a pulse generator and were assigned randomly in a crossover design to two 8-week intervals of active or sham stimulation. At the end of the two trial periods, the patients received active stimulation until the final evaluation at 1 year.

Results

Thirty-six patients (34 women; mean(s.d.) age 45(14) years) underwent peripheral nerve evaluation. Twenty responded and received a permanent stimulator. A positive response was observed in 12 of 20 and 11 of 20 patients after active and sham stimulation periods respectively (P = 0·746). Pain related to the device occurred in five patients and wound infection or haematoma in three, leading to definitive removal of the pulse generator in two patients. At 1 year, 11 of the 20 patients with an implanted device continued to respond. Stimulation had no significant effect on colonic transit time.

Conclusion

These results do not support the recommendation of permanent implantation of a pulse generator in patients with refractory constipation who initially responded to temporary nerve stimulation. Registration number: NCT01629303 (http://www.clinicaltrials.gov).

Iron around the clock

Carbon assimilation, a key determinant of plant biomass production, is under circadian regulation. Light and temperature are major inputs of the plant clock that control various daily rhythms. Such rhythms confer adaptive advantages to the organisms by adjusting their metabolism in anticipation of environmental fluctuations. The relationship between the circadian clock and nutrition extends far beyond the regulation of carbon assimilation as mineral nutrition, and specially iron homeostasis, is regulated through this mechanism. Conversely, iron status was identified as a new and important input regulating the central oscillator, raising the question of the nature of the Fe-dependent signal that modulates the period of the circadian clock. Several lines of evidence strongly suggest that fully developed and functional chloroplasts as well as early light signalling events, involving phytochromes, are essential to couple the clock to Fe responses. Nevertheless, the exact nature of the signal, which most probably involves unknown or not yet fully characterized elements of the chloroplast-to-nucleus retrograde signalling pathway, remains to be identified. Finally, this regulation may also involves epigenetic components.

Post-operative adhesions after digestive surgery: their incidence and prevention: review of the literature

INTRODUCTION

Post-operative adhesions after gastrointestinal surgery are responsible for significant morbidity and constitute an important public health problem. The aim of this study was to review the surgical literature to determine the incidence, consequences and the variety of possible countermeasures to prevent adhesion formation.

METHODS

A systematic review of English and French language surgical literature published between 1995 and 2009 was performed using the keywords "adhesion" and "surgery".

RESULTS

Peritoneal adhesions are reported as the cause of 32% of acute intestinal obstruction and 65-75% of all small bowel obstructions. It is estimated that peritoneal adhesions develop after 93-100% of upper abdominal laparotomies and after 67-93% of lower abdominal laparotomies. Nevertheless, only 15-18% of these adhesions require surgical re-intervention. The need for re-intervention for adhesion-related complications varies depending on the initial type of surgery, the postoperative course and the type of incision. The laparoscopic approach appears to decrease the risk of adhesion formation by 45% and the need for adhesion-related re-intervention to 0.8% after appendectomy and to 2.5% after colorectal surgery. At the present time, only one product consisting of hyaluronic acid applied to a layer of carboxymethylcellulose (Seprafilm(®)) has been shown to significantly reduce the incidence of postoperative adhesion formation; but this product is also associated with a significant increase in the incidence of anastomotic leakage when the membrane is applied in direct contact with the anastomosis. The use of this product has not been shown to decrease the risk of re-intervention for bowel obstruction.

CONCLUSIONS

The prevention of postoperative adhesions is an important public health goal, particularly in light of the frequency of this complication. The routine use of anti-adhesion products is not recommended given the lack of studies with a high level of evidence concerning their efficacy and safety of use.

[Fissure syndrome of a gastrointestinal artery pseudoaneurysm in contact with a pseudocyst of the pancreas: rare, but serious complication of chronic pancreatitis]

Most pseudoaneurysms (PsA) of the peripancreatic arteries cause direct erosion of the arterial wall from pancreatic enzymes that are usually in contact with or in a pseudocyst (PC). Rupturing is a rare and serious complication (90% mortality if untreated). We report the case of a 56-year-old patient with chronic alcoholic pancreatitis who developed a cephaloisthmic PC, complicated with a PsA of the gastroduodenal artery revealed by pain and deglobulization associated with cholestasis. After a diagnostic scan, emergency selective arteriography with coil embolization was performed. Five days later, hemorrhage recurred and a cephalic duodenopancreatectomy was performed. PsA of the gastroduodenal artery occur in the first 10 years of chronic pancreatitis. They are revealed by abdominal pains and/or gastrointestinal hemorrhage or shock from rupture. A scan with arterial reconstruction provides diagnosis. Arteriography is the most sensitive technique to locate the aneurysm and its branches and to perform selective embolization with coils. The failure rate is between 0 and 23%. Surgical treatment (elective ligation of the artery or partial pancreatic excision) should be limited to when embolisation fails and/or recurrent hemorrhage.

[Precancerous lesions of the gallbladder]

This Mini-review summarizes the epidemiology, predisposing and pre-cancerous conditions related to carcinoma of the gallbladder. In 75% of cases, gallbladder cancer is a cholangiocarcinoma, usually presenting in a late and advanced stage, and it carries one of the worst prognoses of all GI malignancies. Early stage disease is usually discovered incidentally by the pathologist in a gallbladder specimen removed for calculous cholecystitis. It occurs three times more frequently in women than in men and invasive forms usually occur after the age of 60. Incidence varies with geographic location. Besides genetic and geographic factors, the presence of one or more large gallstones is a major risk factor. Gallbladder polyps larger than 1.5 cm. (especially solitary sessile hypoechogenic polyps) are associated with a 50% risk of malignancy. Choledochal cysts and other variations of the biliopancreatic junction are also associated with high risk; cancer may occur at a much younger age in these patients and in the absence of gallstones. Porcelain gallbladder is a risk factor, particularly when there is calcification of the gallbladder mucosa. Chronic gallbladder infection has been implicated as a risk factor for malignant degeneration. Finally, cancer of both the gallbladder and the bile ducts is more frequent in patients suffering from primary biliary cirrhosis.

Laparoscopic hyperthermic intraperitoneal chemotherapy (HIPEC) for the treatment of malignant ascites secondary to unresectable peritoneal carcinomatosis from advanced gastric cancer

AIMS

To review our experience of laparoscopic hyperthermic intraperitoneal chemotherapy (HIPEC) in the treatment of malignant ascites from advanced gastric cancer in order to discuss benefits, problems and possible indications.

METHODS

From June 2000 to May 2003 laparoscopic approach was used to perform HIPEC on five patients affected by malignant ascites secondary to unresectable peritoneal carcinomatosis of gastric origin, in order to associate the benefits of a definitive palliation of ascites with a minimal invasiveness. All patients had ascites related symptoms requiring iterative paracenteses. Intraperitoneal perfusion of mitomycin-C and cisplatin was delivered for 60-90min with an inflow temperature of 45 degrees C.

RESULTS

Complete clinical regression of ascites and related symptoms was achieved in all the five patients treated. Intraoperative course was uneventful in all cases. Mean operative time was 181min. No postoperative deaths, related to the procedure, occurred. Only a case of delayed gastric empting was recorded as a minor postoperative complication.

CONCLUSIONS

Laparoscopic HIPEC appears to be a safe and effective procedure to treat debilitating malignant ascites from unresectable peritoneal carcinomatosis.

[Laparoscopic liver surgery for metastases of colorectal cancer: analysis of a monocentric experience]

BACKGROUND

Advances in laparoscopic techniques, refinements of instruments and growth of practical experience in liver surgery during the last decade have prompted some surgeons to develop the laparoscopic approach for hepatic metastases of colorectal cancer (MCRC).

AIMS

Primary end points of this clinical study were safety and effectiveness of laparoscopic hepatectomy for MCRC, including early postoperative results and long-term outcomes (overall survival and disease-free survival).

DESIGN

Retrospective analysis of data (clinicopathologic, operative, perioperative ad late results) collected in a prospective database.

PATIENTS

Between January 1997 and December 2004, 37 non-consecutive (selected) patients underwent curative laparoscopic hepatic resection (n = 42) for MCRC at Montsouris Institut of Paris. Resection was considered when all liver metastases can be totally removed with clear margins, and in absence of nonresectable extrahepatic diseases. Among them were 24 males and 13 females with average ages of 63.4 years (range, 42-78).

RESULTS

Metastases were metachronous in 18, multiple in 21, bilateral in 12, and <5 cm in diameter in 30. There were 21 major hepatectomies (n = 3 Couinaud's segments or more), 4 anatomical minor resections, and 12 wedge resections. Mean operative time was 324 +/- 105 mins. Conversion to laparotomy was necessary in 6 patients (16%), due to massive intractable bleeding in 3 patients, multiples adhesions in 1 patient, technical reasons (location of the lesion) in 1 patient, and for presence of localized carcinosis in 1 patient. Portal triad clamping was performed in 6 patients. Mean operative blood loss was 797 +/- 645 ml, and transfusions were required in 4 patients (11%). Clear resection margins (> 5 mm) were observed in 94%. Postoperative mortality was nil. The overall morbidity rate was 35%, with 2 early reoperations due to hemorrhage and postoperative ileus. Overall and disease free survival at 36 months were 87% and 55%, respectively. Five patients who had a recurrence of metastatic liver disease were referred to a second laparoscopic resection.

CONCLUSION

This clinical study suggests that laparoscopic liver surgery for metastatic colorectal cancer can be accomplished safely, in selected patients and by experienced surgeons, with good early results and without detrimental consequences on survival.

Extent of oesophageal resection for adenocarcinoma of the oesophagogastric junction

AIMS

The optimal extent of oesophageal resection and surgical approach in patients treated for adenocarcinomas of the oesophagogastric junction (OGJ) are still uncertain. We report the correlations between resection margin involvement and outcome.

METHODS

Patients with positive proximal resection margin (PPRM) and those with negative proximal resection margin (NPRM) were compared.

RESULTS

Of 94 patients with macroscopically complete resection, eight were PPRM. There was no difference between the two groups in postoperative mortality or morbidity rates, in anastomotic leakage or in recurrence rates. The median survival in the PPRM group was 11.1 months compared with 36.3 months in the NPRM group (P=0.02). No infiltration was observed in patients whose proximal margin exceeded 7 cm. The extended transthoracic approach was the only prognostic factor for tumours type II (P=0.03, RR=1.4, 95% CI: 1.1-1.8).

CONCLUSION

Histologic infiltration of oesophageal resection margin influences 5-year survival rate. In adenocarcinomas of the OGJ that can be treated curatively, a transection with a 8 cm oesophagectomy above the tumour in fresh specimen should be performed, and by thoracoabdominal approach for tumours type I and II.

Surgical management of and long-term survival after adenocarcinoma of the cardia

BACKGROUND

The choice of surgical strategy for patients with adenocarcinoma of the oesophagogastric junction is controversial. This study was performed to analyse the surgical results of a 20-year experience with these lesions.

METHODS

From January 1981 to January 2001, 126 patients with adenocarcinoma of the cardia underwent resection in the authors' institution. The treatment of choice was oesophagectomy for type I tumours, and extended gastrectomy for type II and III lesions. Morbidity, mortality and survival were determined retrospectively.

RESULTS

Fifty-six patients (44.4 per cent) had type I tumours, 44 (34.9 per cent) type II and 26 (20.6 per cent) type III. Primary resection was performed in 113 patients (89.7 per cent). Oesophagectomy with resection of the proximal stomach was carried out in 65 patients (51.6 per cent) and extended total gastrectomy with transhiatal resection of the distal oesophagus in 61 (48.4 per cent). In-hospital mortality and morbidity rates were 4.8 and 34.1 per cent respectively. The overall 3- and 5-year survival rates were 40.9 and 25.1 per cent respectively, and were not affected by the surgical approach. Survival was significantly associated with R0 resection, pathological node-positive category, postoperative complications and tumour differentiation.

CONCLUSION

Postoperative mortality, morbidity and long-term survival did not appear to be affected by surgical approach. Further prospective studies are needed to confirm the equivalence between transthoracic and transabdominal approaches.

[Adenocarcinomas of the distal esophagus and cardia: surgical management]

Adenocarcinoma of the esogastric junction is increasing more rapidly than any other cancer in western country. Patients with carcinoma of the cardia often present at an advanced stage of disease. Accurate preoperative staging of cancer of the cardia need computed tomography, endoscopic ultrasound: laparoscopy is useful for advanced cancer to detect liver and peritoneal metastatis, preventing an unnecessary laparotomy in up to 20% of patients. The Siewert's classification of the cancer of the esogastric junction is accepted internationally: type I: tumor center within the late 5 cm of the distal esophagus, treated with subtotal esophagectomy; type II: located at the esogastric junction, treated with distal esophagectomy and, either proximal or total gastrectomy; and type III: subcardial cancer, treated by extended total gastrectomy. The dominating independent prognostic factors are a complete resection (R0) and the lymph node status (pN0) Expected 5 year survival rate is 30% in patients undergoing surgery with curative intent (R0) and less than 1% in patients undergoing palliative surgery.

[The use of electroconvulsive therapy in acute services at the general hospital]

GOAL

The aim of the investigation focused on a retrospective analysis of the clinical use of ECT in the Acute Psychiatric Unit of The University Hospital of Guadalajara.

METHOD

All patients admitted to our psychiatric unit from 1993 to 1998 and who underwent ECT along their hospitalization, were included in the analysis. Age of the sample ranged from 17 to 79. Several variables were controlled, including technical parameters of ETC application.

RESULTS

All patients with a diagnosis of bipolar disorder or schizoaffective disorder showed full remission after ECT. Among patients diagnosed of schizophrenia, 60% experimented full remission and 40% partial remission. In the group of subjects with depression, 66.6% showed full remission, 27.7% partial remission and 5.7% no response. Besides, ETC appeared to be more effective in subjects without psychiatric comorbidity.

CONCLUSION

The present retrospective analysis support that ECT still must be considered an effective, useful and safe therapeutic technique. In our review, adverse reactions to ECT have been limited and rare, and mostly reversible.

Skin reactions to hydroxyzine

Sensitivity to histamine H1-antagonists has mainly been observed with phenothiazine and ethylenediamine, and is very rare with hydroxyzine. We report 3 cases of sensitization to hydroxyzine, which was prescribed to treat urticaria and atopic dermatitis. A generalized maculopapular eruption appeared shortly after taking the drug. Patch tests with Atarax tablet were positive +3, and +2 or +3 with different dilutions of hydroxyzine. Patch tests with ethylenediamine, piperazine and other antihistamines were negative; therefore, there is no cross-allergy. We believe these rapid systemic reactions to hydroxyzine after the initial dose may have been due to prior systemic sensitivity to this drug, which cannot be used topically. Allergy to antihistamines must be considered when cutaneous lesions worsen on such therapy.

Occupational contact dermatitis from propacetamol

We report 4 cases of contact sensitization to propacetamol. They presented with lesions on the hands, forearms, crease of the elbows, and neck. They were all sensitized to multiple allergens and 2 of them were atopic. Patch tests to Pro-Dafalgan and propacetamol were positive; sodium citrate and paracetamol were negative. Our cases were similar to those published for the first time by Barbaud in 1995. The only allergen was propacetamol; patch tests with diethyglycine and paracetamol were negative. Propacetamol chlorhydrate is composed of a complex paracetamol-diethylglycine, which probably acts like a hapten capable of inducing cutaneous allergy. It is an occupational allergy affecting nurses who work in surgery departments or post-anesthesia recovery rooms, where high doses of analgesics are widely used. The patients were not allergic to oral paracetamol. Despite the usual precautions, the mixture of propacetamol chlorhydrate and solvent leaks onto the nurses' hands, suggesting that health care workers handling propacetamol chlorhydrate should wear gloves.

Eczematous-like drug eruption induced by synergistins

The authors report 4 cases of eczematous-like drug eruption after oral ingestion of synergistins, pristinamycin (3 cases) and virginiamycin (1 case). The lesions occurred after contact sensitization with topical virginiamycin. The clinical symptoms appeared a few hours after ingestion: a generalized maculopapular eruption, sometimes with general symptoms of anaphylactic reaction. Eczema appeared again on initial areas of contact dermatitis. There is a common allergenic group between these 2 antibiotics, which is a macrocyclic lactone. Physiopathology of this drug eruption is not clear: allergic reaction of the delayed type or anaphylactic reaction. Patients allergic to virginiamycin should be strongly cautioned against oral pristinamycin.

Contact dermatitis from a textile flame retardant

We report a case of contact sensitivity to Flammentin ASN, a flame retardant used on cotton and wool. The patient was a painter who was protecting his face with a white cotton cap. He presented with eczema of the forehead at the sites of cap contact. Patch tests with the treated cap and flame retardant were positive; a formaldehyde patch test was negative. Flame retardants are used in construction, materials and textiles. Contact sensitivity is rarely described and we compare our case to those published in the literature.