DiSiR: fast and robust method to identify ligand–receptor interactions at subunit level from single-cell RNA-sequencing data

Most cell–cell interactions and crosstalks are mediated by ligand–receptor interactions. The advent of single-cell RNA-sequencing (scRNA-seq) techniques has enabled characterizing tissue heterogeneity at single-cell level. In the past few years, several methods have been developed to study ligand–receptor interactions at cell type level using scRNA-seq data. However, there is still no easy way to query the activity of a specific user-defined signaling pathway in a targeted way or to map the interactions of the same subunit with different ligands as part of different receptor complexes. Here, we present DiSiR, a fast and easy-to-use permutation-based software framework to investigate how individual cells are interacting with each other by analyzing signaling pathways of multi-subunit ligand-activated receptors from scRNA-seq data, not only for available curated databases of ligand–receptor interactions, but also for interactions that are not listed in these databases. We show that, when utilized to infer ligand–receptor interactions from both simulated and real datasets, DiSiR outperforms other well-known permutation-based methods, e.g. CellPhoneDB and ICELLNET. Finally, to demonstrate DiSiR’s utility in exploring data and generating biologically relevant hypotheses, we apply it to COVID lung and rheumatoid arthritis (RA) synovium scRNA-seq datasets and highlight potential differences between inflammatory pathways at cell type level for control versus disease samples.

Expression and subcellular localization of USH1C/harmonin in human retina provides insights into pathomechanisms and therapy

Usher syndrome (USH) is the most common form of hereditary deaf-blindness in humans. USH is a complex genetic disorder, assigned to three clinical subtypes differing in onset, course and severity, with USH1 being the most severe. Rodent USH1 models do not reflect the ocular phenotype observed in human patients to date; hence, little is known about the pathophysiology of USH1 in the human eye. One of the USH1 genes, USH1C, exhibits extensive alternative splicing and encodes numerous harmonin protein isoforms that function as scaffolds for organizing the USH interactome. RNA-seq analysis of human retinae uncovered harmonin_a1 as the most abundant transcript of USH1C. Bulk RNA-seq analysis and immunoblotting showed abundant expression of harmonin in Müller glia cells (MGCs) and retinal neurons. Furthermore, harmonin was localized in the terminal endfeet and apical microvilli of MGCs, presynaptic region (pedicle) of cones and outer segments (OS) of rods as well as at adhesive junctions between MGCs and photoreceptor cells (PRCs) in the outer limiting membrane (OLM). Our data provide evidence for the interaction of harmonin with OLM molecules in PRCs and MGCs and rhodopsin in PRCs. Subcellular expression and colocalization of harmonin correlate with the clinical phenotype observed in USH1C patients. We also demonstrate that primary cilia defects in USH1C patient-derived fibroblasts could be reverted by the delivery of harmonin_a1 transcript isoform. Our studies thus provide novel insights into PRC cell biology, USH1C pathophysiology and development of gene therapy treatment(s).

Benchmarking computational methods for B-cell receptor reconstruction from single-cell RNA-seq data

Multiple methods have recently been developed to reconstruct full-length B-cell receptors (BCRs) from single-cell RNA sequencing (scRNA-seq) data. This need emerged from the expansion of scRNA-seq techniques, the increasing interest in antibody-based drug development and the importance of BCR repertoire changes in cancer and autoimmune disease progression. However, a comprehensive assessment of performance-influencing factors such as the sequencing depth, read length or number of somatic hypermutations (SHMs) as well as guidance regarding the choice of methodology is still lacking. In this work, we evaluated the ability of six available methods to reconstruct full-length BCRs using one simulated and three experimental SMART-seq datasets. In addition, we validated that the BCRs assembled in silico recognize their intended targets when expressed as monoclonal antibodies. We observed that methods such as BALDR, BASIC and BRACER showed the best overall performance across the tested datasets and conditions, whereas only BASIC demonstrated acceptable results on very short read libraries. Furthermore, the de novo assembly-based methods BRACER and BALDR were the most accurate in reconstructing BCRs harboring different degrees of SHMs in the variable domain, while TRUST4, MiXCR and BASIC were the fastest. Finally, we propose guidelines to select the best method based on the given data characteristics.

RNA Sequencing of Human Peripheral Blood Cells Indicates Upregulation of Immune-Related Genes in Huntington's Disease

Huntington's disease (HD) is an autosomal dominantly inherited neurodegenerative disorder caused by a trinucleotide repeat expansion in the Huntingtin gene. As disease-modifying therapies for HD are being developed, peripheral blood cells may be used to indicate disease progression and to monitor treatment response. In order to investigate whether gene expression changes can be found in the blood of individuals with HD that distinguish them from healthy controls, we performed transcriptome analysis by next-generation sequencing (RNA-seq). We detected a gene expression signature consistent with dysregulation of immune-related functions and inflammatory response in peripheral blood from HD cases vs. controls, including induction of the interferon response genes, IFITM3, IFI6 and IRF7. Our results suggest that it is possible to detect gene expression changes in blood samples from individuals with HD, which may reflect the immune pathology associated with the disease.

Computational identification of cell-specific variable regions in ChIP-seq data

Chromatin immunoprecipitation followed by sequencing (ChIP-seq) is used to identify genome-wide DNA regions bound by proteins. Given one ChIP-seq experiment with replicates, binding sites not observed in all the replicates will usually be interpreted as noise and discarded. However, the recent discovery of high-occupancy target (HOT) regions suggests that there are regions where binding of multiple transcription factors can be identified. To investigate ChIP-seq variability, we developed a reproducibility score and a method that identifies cell-specific variable regions in ChIP-seq data by integrating replicated ChIP-seq experiments for multiple protein targets on a particular cell type. Using our method, we found variable regions in human cell lines K562, GM12878, HepG2, MCF-7 and in mouse embryonic stem cells (mESCs). These variable-occupancy target regions (VOTs) are CG dinucleotide rich, and show enrichment at promoters and R-loops. They overlap significantly with HOT regions, but are not blacklisted regions producing non-specific binding ChIP-seq peaks. Furthermore, in mESCs, VOTs are conserved among placental species suggesting that they could have a function important for this taxon. Our method can be useful to point to such regions along the genome in a given cell type of interest, to improve the downstream interpretative analysis before follow-up experiments.

Formulating octyl methoxycinnamate in hybrid lipid-silica nanoparticles: An innovative approach for UV skin protection

Sunscreens have been employed on daily skin care for centuries. Their role in protecting the skin from sun damage, avoiding accelerated photoaging and even limiting the risk of development of skin cancer is unquestionable. Although several chemical and physical filters are approved as sunscreens for human use, their safety profile is dependent on their concentration in the formulation which governs their acceptance by the regulatory agencies. A strategic delivery of such molecules should provide a UV protection and limit the skin penetration. Solid lipid nanoparticles (SLN) and nanostructured lipid carriers (NLC) may offer an alternative approach to achieve a synergistic effect on the UV protection when loaded with sunscreens as particles themselves also have a UV light scattering effect. Besides, the lipid character of SLN and NLC improves the encapsulation of lipophilic compounds, with enhanced loading capacity. Silica nanoparticles have also been employed in sunscreen formulations. Due to the formed sol-gel complexes, which covalently entrap sunscreen molecules, a controlled release is also achieved. In the present work, we have developed a new sunscreen formulation composed of hybrid SLN-Silica particles loaded with octyl methoxycinnamate (Parsol®MCX), and their further incorporation into a hydrogel for skin administration. Hybrid SLN-silica particles of 210.0 ± 3.341 nm of mean size, polydispersity below 0.3, zeta potential of ca. |7| mV, loading capacity of 19.9% and encapsulation efficiency of 98.3% have been produced. Despite the slight negative surface charge, the developed hybrid nanoparticles remained physicochemically stable over the study period. Turbiscan transmission profiles confirmed the colloidal stability of the formulations under stress conditions. The texture profile analysis of Parsol-SLN and Parsol-SLN-Si revealed semi-solid properties (e.g. adhesiveness, hardness, cohesiveness, springiness, gumminess, chewiness, resilience) suitable for topical application, together with the bioadhesiveness in the skin of pig ears. The non-irritation profile of the hybrid nanoparticles before and after dispersion into Carbopol hydrogels was confirmed by HET-CAM test.

cis-regulatory variation modulates susceptibility to enteric infection in the Drosophila genetic reference panel

BACKGROUND

Resistance to enteric pathogens is a complex trait at the crossroads of multiple biological processes. We have previously shown in the Drosophila Genetic Reference Panel (DGRP) that resistance to infection is highly heritable, but our understanding of how the effects of genetic variants affect different molecular mechanisms to determine gut immunocompetence is still limited.

RESULTS

To address this, we perform a systems genetics analysis of the gut transcriptomes from 38 DGRP lines that were orally infected with Pseudomonas entomophila. We identify a large number of condition-specific, expression quantitative trait loci (local-eQTLs) with infection-specific ones located in regions enriched for FOX transcription factor motifs. By assessing the allelic imbalance in the transcriptomes of 19 F1 hybrid lines from a large round robin design, we independently attribute a robust cis-regulatory effect to only 10% of these detected local-eQTLs. However, additional analyses indicate that many local-eQTLs may act in trans instead. Comparison of the transcriptomes of DGRP lines that were either susceptible or resistant to Pseudomonas entomophila infection reveals nutcracker as the only differentially expressed gene. Interestingly, we find that nutcracker is linked to infection-specific eQTLs that correlate with its expression level and to enteric infection susceptibility. Further regulatory analysis reveals one particular eQTL that significantly decreases the binding affinity for the repressor Broad, driving differential allele-specific nutcracker expression.

CONCLUSIONS

Our collective findings point to a large number of infection-specific cis- and trans-acting eQTLs in the DGRP, including one common non-coding variant that lowers enteric infection susceptibility.

Enteric infection induces Lark-mediated intron retention at the 5' end of Drosophila genes

BACKGROUND

RNA splicing is a key post-transcriptional mechanism that generates protein diversity and contributes to the fine-tuning of gene expression, which may facilitate adaptation to environmental challenges. Here, we employ a systems approach to study alternative splicing changes upon enteric infection in females from classical Drosophila melanogaster strains as well as 38 inbred lines.

RESULTS

We find that infection leads to extensive differences in isoform ratios, which results in a more diverse transcriptome with longer 5' untranslated regions (5'UTRs). We establish a role for genetic variation in mediating inter-individual splicing differences, with local splicing quantitative trait loci (local-sQTLs) being preferentially located at the 5' end of transcripts and directly upstream of splice donor sites. Moreover, local-sQTLs are more numerous in the infected state, indicating that acute stress unmasks a substantial number of silent genetic variants. We observe a general increase in intron retention concentrated at the 5' end of transcripts across multiple strains, whose prevalence scales with the degree of pathogen virulence. The length, GC content, and RNA polymerase II occupancy of these introns with increased retention suggest that they have exon-like characteristics. We further uncover that retained intron sequences are enriched for the Lark/RBM4 RNA binding motif. Interestingly, we find that lark is induced by infection in wild-type flies, its overexpression and knockdown alter survival, and tissue-specific overexpression mimics infection-induced intron retention.

CONCLUSION

Our collective findings point to pervasive and consistent RNA splicing changes, partly mediated by Lark/RBM4, as being an important aspect of the gut response to infection.

Assessment of computational methods for the analysis of single-cell ATAC-seq data

BACKGROUND

Recent innovations in single-cell Assay for Transposase Accessible Chromatin using sequencing (scATAC-seq) enable profiling of the epigenetic landscape of thousands of individual cells. scATAC-seq data analysis presents unique methodological challenges. scATAC-seq experiments sample DNA, which, due to low copy numbers (diploid in humans), lead to inherent data sparsity (1-10% of peaks detected per cell) compared to transcriptomic (scRNA-seq) data (10-45% of expressed genes detected per cell). Such challenges in data generation emphasize the need for informative features to assess cell heterogeneity at the chromatin level.

RESULTS

We present a benchmarking framework that is applied to 10 computational methods for scATAC-seq on 13 synthetic and real datasets from different assays, profiling cell types from diverse tissues and organisms. Methods for processing and featurizing scATAC-seq data were compared by their ability to discriminate cell types when combined with common unsupervised clustering approaches. We rank evaluated methods and discuss computational challenges associated with scATAC-seq analysis including inherently sparse data, determination of features, peak calling, the effects of sequencing coverage and noise, and clustering performance. Running times and memory requirements are also discussed.

CONCLUSIONS

This reference summary of scATAC-seq methods offers recommendations for best practices with consideration for both the non-expert user and the methods developer. Despite variation across methods and datasets, SnapATAC, Cusanovich2018, and cisTopic outperform other methods in separating cell populations of different coverages and noise levels in both synthetic and real datasets. Notably, SnapATAC is the only method able to analyze a large dataset (> 80,000 cells).

GADD45 promotes locus-specific DNA demethylation and 2C cycling in embryonic stem cells

In this study, Schüle et al. report an unexpected role of GADD45 proteins in regulation of the cycling of ESCs in the 2C state. Using methylome analysis of Gadd45 triple-mutant ESCs, they found a role for GADD45 in demethylation of specific TET targets and partial deregulation of ZGA genes at the two-cell stage.

Mouse embryonic stem cell (ESC) cultures contain a rare cell population of “2C-like” cells resembling two-cell embryos, the key stage of zygotic genome activation (ZGA). Little is known about positive regulators of the 2C-like state and two-cell stage embryos. Here we show that GADD45 (growth arrest and DNA damage 45) proteins, regulators of TET (TET methylcytosine dioxygenase)-mediated DNA demethylation, promote both states. Methylome analysis of Gadd45a,b,g triple-knockout (TKO) ESCs reveal locus-specific DNA hypermethylation of ∼7000 sites, which are enriched for enhancers and loci undergoing TET–TDG (thymine DNA glycosylase)-mediated demethylation. Gene expression is misregulated in TKOs, notably upon differentiation, and displays signatures of DNMT (DNA methyltransferase) and TET targets. TKOs manifest impaired transition into the 2C-like state and exhibit DNA hypermethylation and down-regulation of 2C-like state-specific genes. Gadd45a,b double-mutant mouse embryos display embryonic sublethality, deregulated ZGA gene expression, and developmental arrest. Our study reveals an unexpected role of GADD45 proteins in embryonic two-cell stage regulation.

Toxicological impact of cadmium-based quantum dots towards aquatic biota: Effect of natural sunlight exposure

Cadmium-based quantum dots (QDs) are increasingly applied in existent and emerging technologies, especially in biological applications due to their exceptional photophysical and functionalization properties. However, they are very toxic compounds due to the high reactive and toxic cadmium core. The present study aimed to determine the toxicity of three different QDs (CdS 380, CdS 480 and CdSeS/ZnS) before and after the exposure of suspensions to sunlight, in order to assess the effect of environmentally relevant irradiation levels in their toxicity, which will act after their release to the environment. Therefore, a battery of ecotoxicological tests was performed with organisms that cover different functional and trophic levels, such as Vibrio fischeri, Raphidocelis subcapitata, Chlorella vulgaris and Daphnia magna. The results showed that core-shell type QDs showed lower toxic effects to V. fischeri in comparison to core type QDs before sunlight exposure. However, after sunlight exposure, there was a decrease of CdS 380 and CdS 480 QD toxicity to bacterium. Also, after sunlight exposure, an effective decrease of CdSeS/ZnS and CdS 480 toxicity for D. magna and R. subcapitata, and an evident increase in CdS 380 QD toxicity, at least for D. magna, were observed. The results of this study suggest that sunlight exposure has an effect in the aggregation and precipitation reactions of larger QDs, causing the degradation of functional groups and formation of larger bulks which may be less prone to photo-oxidation due to their diminished surface area. The same aggregation behaviour after sunlight exposure was observed for bare QDs. These results further emphasize that the shell of QDs seems to make them less harmful to aquatic biota, both under standard environmental conditions and after the exposure to a relevant abiotic factor like sunlight.

d-α-tocopherol nanoemulsions: Size properties, rheological behavior, surface tension, osmolarity and cytotoxicity

The aim of this study was the assessment of the physicochemical stability of d-α-tocopherol formulated in medium chain triglyceride nanoemulsions, stabilized with Tween®80 and Lipoid®S75 as surfactant and co-surfactant, respectively. d-α-tocopherol was selected as active ingredient because of its well-recognized interesting anti-oxidant properties (such as radical scavenger) for food and pharmaceutical industries. A series of nanoemulsions of mean droplet size below 90 nm (polydispersity index < 0.15) have been produced by high-pressure homogenization, and their surface electrical charge (zeta potential), pH, surface tension, osmolarity, and rheological behavior, were characterized as a function of the d-α-tocopherol loading. In vitro studies in Caco-2 cell lines confirmed the safety profile of the developed nanoemulsions with percentage of cell viability above 90% for all formulations.

Sequential treatment with lamivudine and interferon monotherapies in patients with chronic hepatitis B not responding to interferon alone: results of a pilot study

Sustained viral suppression using monotherapy with interferon alfa (IFN-alpha) or lamivudine can only be achieved in a small percentage of patients with chronic hepatitis B. The concomitant administration of lamivudine and IFN-alpha does not enhance efficacy. We postulated that the optimal timing of therapy might be sequential treatment with lamivudine and IFN-alpha. The aim of this study was therefore to assess the efficacy of sequential treatment in patients resistant to IFN-alpha alone. Fourteen male patients, with a median age of 40 years, nonresponders to IFN-alpha with hepatitis B virus (HBV) DNA > 100 pg/mL (branched DNA [bDNA] Chiron) and positive hepatitis B e antigen (HBeAg) in 11 of 14 patients, were treated with lamivudine 100 mg/d alone for 20 weeks, then with both IFN-alpha2b 5 MU 3 times per week and lamivudine for 4 weeks, and lastly with IFN-alpha alone for 24 weeks. At the end of lamivudine therapy, all patients had undetectable serum HBV DNA, and none exhibited an emergence of HBV polymerase mutant or breakthrough. Sustained serum HBV-DNA clearance 6 months after the end of sequential treatment was achieved in 8 of 14 patients, HBeAg-to-anti-HBe seroconversion in 5 of 11 patients, and HBeAg and hepatitis B surface antigen (HBsAg) seroconversions in 3 of 14 patients (anti-HBs > 100 IU/mL). All sustained responders had normalized their alanine transaminase (ALT) values and exhibited histologic improvements. In conclusion, the results of this pilot study suggest that sequential treatment with lamivudine and IFN-alpha can induce a sustained virologic response, including HBs seroconversion, in patients with chronic hepatitis B not responding to IFN-alpha alone, without the selection of drug-resistant mutants. This therapeutic schedule warrants further evaluation in clinical trials.

Hepatitis C virus induced hypobetalipoproteinemia: a possible mechanism for steatosis in chronic hepatitis C

BACKGROUND/AIMS

Steatosis could be the result of HCV (hepatitis C virus)-induced hypobetalipoproteinemia in patients with chronic hepatitis C. The aim of this study was to assess serum levels of main constituents of betalipoproteins and their relationship with steatosis in patients with chronic hepatitis C without known risk factors for steatosis.

PATIENTS

One-hundred male patients with untreated biopsy proven non-cirrhotic chronic hepatitis C were included. Twenty-nine of these patients were further treated with interferon.

RESULTS

Cholesterol concentration was significantly lower in patients compared to three control groups: reference male population, patients with chronic hepatitis B or with non-alcoholic fatty liver. In multivariate analysis, low apolipoprotein B concentration was an independent factor related with the degree of steatosis. Hypobetalipoproteinemia and degree of steatosis were significantly associated with infection with genotype 3. Among treated patients, only sustained virological responders had a significant increase of cholesterol (5.6 +/- 1 vs. 4.7 +/- 1.3 mmol/l; P = 0.03) and apolipoprotein B concentrations (113 +/- 19 vs. 75 +/- 14 mg/dl; P = 0.05).

CONCLUSION

In chronic hepatitis C, hypobetalipoproteinemia is prevalent and associated with steatosis, especially in patients infected with genotype 3. The correction of hypobetalipoproteinemia following HCV eradication suggests that HCV itself could induce hypobetalipoproteinemia and steatosis.

Safety and immunogenicity of an inactivated subunit influenza virus vaccine combined with MF59 adjuvant emulsion in elderly subjects, immunized for three consecutive influenza seasons

A clinical trial to evaluate the safety and tolerability of a new influenza adjuvanted vaccine (FLUAD, Chiron Vaccines), compared with a conventional non adjuvanted influenza vaccine, was conducted in elderly ambulatory patients. Subjects were vaccinated with one dose of either vaccine each year for three consecutive years; 92 subjects received the first immunization, 74 subjects received the second and 67 subjects received the third. The primary objective of this study was to evaluate the safety of repetitive injections of the adjuvanted vaccine in elderly subjects. There were no reports of any vaccine-related serious adverse event or of safety concerns related to study vaccines after the first, second or third immunization. The adjuvanted vaccine induced more local reactions than the conventional vaccine; however, the reactions were normally mild and limited to the first 2-3 days after immunization. No statistically significant difference between groups in systemic postimmunization reactions was reported except for a mild, transient malaise after the first immunization. Compared with the first immunization, no increase in postimmunization reactions was seen after the second and third immunizations. Despite the small sample size of the trial, which was not powered to test immunogenicity differences, the antibody response was tested and resulted higher in the adjuvanted vaccine recipients, not only against the current season's vaccine strains, but also against heterologous vaccine strains.

Interferon alfa therapy in patients with chronic hepatitis C and persistently normal aminotransferase activity

BACKGROUND & AIMS

Chronic hepatitis C virus carriers may have repeatedly normal aminotransferase activity despite detectable viremia and histological hepatitis. The aim of this study was to determine the effect of interferon in this population.

METHODS

Three million units of interferon alfa was administered 3 times weekly for 6 months in 10 patients with chronic hepatitis C virus infection, repeatedly normal alanine aminotransferase activity, and chronic hepatitis on liver biopsy. Serum hepatitis C virus RNA was detected by polymerase chain reaction and quantified by branched DNA before, at the end, and 1 year after treatment. A liver biopsy was performed 1 year after treatment withdrawal.

RESULTS

At treatment withdrawal, hepatitis C virus RNA levels had significantly decreased, but RNA was still detectable by polymerase chain reaction in 8 of 10 patients. During the 1-year follow-up period, 6 of 9 patients had elevated aminotransferase activity on at least one occasion. One year after treatment withdrawal, RNA levels had returned to pretreatment values and no significant histological improvement was observed in the 7 patients who underwent liver biopsy.

CONCLUSIONS

In patients with chronic hepatitis C and repeatedly normal aminotransferase activity, standard interferon therapy does not lead to sustained virological or histological responses despite a transient effect on hepatitis C virus replication.

[Association of Gougerot-Sjögren syndrome and viral hepatitis C. Apropos of 6 cases]

Hepatitis C virus (HCV) has been found in the serum of 3 out of 109 patients with Sjögren's syndrome, whereas Sjögren's syndrome has been demonstrated in 3 out of 7 HCV-positive patients. The six HCV-positive Sjögren's syndrome patients were compared with 95 HCV-negative Sjögren's syndrome patients. Anti-smooth muscle antibodies were detected in 1 of the former group and 6 of the latter. Cryoglobulin existed in 1 and 6, respectively. The levels of circulating IgA and IgA-containing immune complexes were lower in the HCV-positive than in the HCV-negative patients.

Preventive therapy of first gastrointestinal bleeding in patients with cirrhosis: results of a controlled trial comparing propranolol, endoscopic sclerotherapy and placebo

Propranolol and endoscopic sclerosis of esophageal varices are the two approaches currently used in prophylaxis of the first gastrointestinal hemorrhage in the cirrhotic patient. One hundred twenty-six cirrhotic patients with esophageal varices and no histories of bleeding were included in the trial regardless of the gravity of the cirrhosis or the size of the esophageal varices. Patients with hepatocarcinomas or other cancers, clearly impossible follow-up, previous treatment for portal hypertension or contraindication to beta-blockers were excluded. After randomization, 43 patients received propranolol twice daily at a dose reducing the heart rate by 25%; 42 patients were treated with intravariceal and extravariceal injections of Polidocanol; 41 control patients received vitamin K orally as placebo. The patients were seen at 3-mo intervals for 2 yr. On entry to the trial the three groups were comparable in terms of clinical and biological parameters, including size of esophageal varices (grade I = 51, grade II = 54, grade III = 17), Child-Pugh classification (A = 29, B = 61, C = 32) and the origin of cirrhosis (alcoholic in 79% of cases). Twenty-four patients bled (two bled in the propranolol group, nine bled in the endoscopic sclerosis of esophageal varices group and 13 bled in the placebo group). Actuarial estimates (Kaplan-Meier) of the time of onset of first bleeding showed that the differences were significant between propranolol and placebo (p less than 0.004) and between propranolol and sclerotherapy (p less than 0.03) but not between sclerotherapy and placebo.(ABSTRACT TRUNCATED AT 250 WORDS)

[Nodular regenerative hyperplasia of the liver and primary biliary cirrhosis. A fortuitous association?]

We report here in a case of primary biliary cirrhosis associated with nodular regenerative hyperplasia of the liver in a white woman revealed by digestive hemorrhage due to ruptured esophageal varices. The diagnosis of primary biliary cirrhosis was based on the following: elevated serum IgM, high titer of antimitochondrial antibody (anti M2), typical histopathological picture of stage I/II disease. The diagnosis of nodular regenerative hyperplasia was supported by the demonstration of disseminated small hepatic nodules without perinodular fibrosis. This association may be a supplementary argument in favor of a possible autoimmune origin of nodular regenerative hyperplasia of the liver.

Acquired immunodeficiency with intestinal cryptosporidiosis: possible transmission by Haitian whole blood

A 31-year-old Frenchman had an acquired immunodeficiency syndrome (AIDS) with profound depression of cellular immunity and relative sparing of humoral immunity. The clinical picture included intractable secretory diarrhoea, vomiting, abdominal pain, and weight loss. Gastrointestinal cryptosporidiosis was present and a perfusion technique showed profuse secretion of fluid in the proximal small bowel. The patient also had recurrent Salmonella typhimurium septicaemia, cytomegalovirus infection, and cerebral toxoplasmosis and he died within 13 months. This patient did not belong to any of the groups known to be affected by this type of acquired immunodeficiency (homosexuals, drug addicts, haemophiliacs, Haitians) but had been transfused with Haitian blood 4 years before onset of symptoms. This case supports the notion that some forms of AIDS may be transmitted by blood, with a long incubation period.