Progressive multifocal leukoencephalopathy despite immune recovery in a HIV/HCV co-infected patient.

In HIV patients, HCV co-infection has been associated with an increased risk of progressive multifocal leukoencephalopathy (PML). Furthermore, PML has also been described in patients with cirrhosis, whether related to HCV infection or not. We describe here the case of a HIV/HCV co-infected patient with cirrhosis who developed PML despite HIV suppression and CD4 cell count above 250/mm3 for 2 years. Immunological studies performed at onset of PML and before HCV therapy showed a decrease in naïve CD4 cells (CD45RA+CCR7+CD27+ CD4+ T cells - 23% cells, i.e. 75/mm3) and NK lymphopenia with abnormal and activated NK cells (CD3- CD16+ and/or CD56+) (5% lymphocytes, i.e. 58/mm3, CD69 91%, NKp30 26%). This impaired immunity, possibly related to HIV infection, or HCV infection or cirrhosis, or a combination thereof, could have led to the development of PML.

Rituximab treatment in seronegative autoimmune autonomic neuropathy and autoimmune autonomic ganglionopathy: Case-report and literature review.

BACKGROUND AND PURPOSE: Autoimmune autonomic ganglionopathy (AAG) is a rare disease with no well-established treatment. Until recently, AAG could be seropositive (50 to 60% of patients) or seronegative for ganglionic (α3-type) nicotinic acetylcholine receptor (Gα3NAChR) antibodies. In early 2018, the two forms of the disease were distinguished, separating seropositive from seronegative ones, designating this latter form "seronegative autoimmune autonomic neuropathy" (SAAN). Most described treatments are plasma exchange (PE) and intravenous immunoglobulin (IVIG). However in some cases with no or small benefit, other immunomodulatory therapies, such as rituximab have been reported. We report the case of a 24-year-old female patient successfully treated for SAAN with rituximab and steroids after IVIG and PE failure. We also provide a review of case-reports reporting rituximab treatment for both SAAN and AAG. METHODS: To identify articles reporting SAAN and AAG treatment with rituximab, we searched the PubMed database using the terms "autoimmune autonomic ganglionopathy", "autoimmune autonomic neuropathy" or "seronegative autoimmune autonomic neuropathy" and "rituximab". RESULTS: Including our patient, nine cases have been described in the literature (4 SAAN and 5 AAG). Rituximab had a significant positive effect in 2 out of 4 SAAN and all 5 AAG cases, used alone or in association with other etiologic treatments. CONCLUSION: Our study suggests rituximab (alone or in association with other treatments) could provide efficacy in both SAAN and AAG when PE and/or IVIG are not effective enough.

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.

Severe acute hepatitis E in an HIV infected patient: Successful treatment with ribavirin.

In industrialized countries, most cases of hepatitis E virus (HEV) infection in humans are autochthonous, mainly through foodborne and zoonotic transmission routes. In Europe, genotype 3 is a cause of acute self-limiting viral hepatitis, but can also be responsible for chronic hepatitis in immunocompromised patients. Ribavirin has been successfully used in the treatment of chronic hepatitis E and in a few cases of severe acute hepatitis E in immunocompetent patients. We report here the case of a 39 year-old man infected with HIV presenting with acute hepatitis E (genotype 3c). Unlike most cases, evolution was severe with a fall of prothrombin time down to 45%. Treatment with ribavirin allowed rapid viral clearance and a gradual normalization of liver function tests.

Effectiveness of infliximab in pityriasis rubra pilaris is associated with pro-inflammatory cytokine inhibition.

BACKGROUND: Pityriasis rubra pilaris (PRP) is a rare inflammatory skin disease. Recently, the use of anti-TNF-α in treating resistant forms of PRP has been reported. OBJECTIVES: To evaluate the clinical efficacy of infliximab in the treatment of PRP along with the evolution of secretion of some serum cytokines during treatment. METHODS: Patients presenting widespread PRP were included consecutively and treated with infliximab. We compared cytokine profiles (notably CXCL-10 and TNF-α) by ELISA in sera from both patients with PRP and controls (healthy/psoriasis) at the time of diagnosis and after clinical remission (PRP). RESULTS: 4 patients were treated with infliximab and achieved complete remission without any recurrence after treatment ending. The serum level of TNF-α and CXCL-10 was increased at the time of inclusion and normalized after treatment. Analysis of the typical component of the T helper cell 1 (Th1) and Th2 cytokine network did not show modification. CONCLUSION: Infliximab is an effective treatment of PRP. The analysis of the cytokine profile is in agreement with an absence of further recurrence of PRP by an early and unique inflammatory mechanism without significant underlying autoimmunity.

Comparison of C4d detection on erythrocytes and PTC-C4d to histological signs of antibody-mediated rejection in kidney transplantation.

C4d on erythrocytes (EC4d), C4d peritubular capillary deposition (PTC-C4d) staining and histology were compared in a cross-sectional cohort of 146 renal allograft biopsies (132 patients). EC4d levels paralleled PTC-C4d staining, but were more predictive of peritubular capillaritis (PTC). Donor-specific antibodies (DSA), PTC-C4d, EC4d and PTC were analyzed in an independent longitudinal follow-up cohort (96 biopsies, 76 patients). Seventy-six samples were PTC and EC4d concordant, 11 positive and 65 negative, 7 PTC-EC4d+ and 13 PTC+EC4d-. EC4d levels were related to DSA occurrence. With ABMR defined by PTC and DSA, all apparently discordant patients, EC4d negative, were correctly reassigned comparing EC4d level curves with rejection kinetics, with positive EC4d samples predating biopsy or late biopsies compared with ABMR flare-ups. All EC4d-positive patients without PTC or DSA had permanent high EC4d levels unrelated to rejection. EC4d was more abundant in PTC-positive (mean = 108.5%± 3.4; n = 50) than PTC-negative samples (mean = 88.1%± 1.3; n= 96; p < 0.0001). Sensitivity, specificity, positive predictive value and negative predictive value of PTC-C4d and EC4d for PTC were, respectively, 75%, 79%; 64%, 76% (p < 0.05); 28%, 46% (p < 0.05) and 93%, 94%. Values were similar for DSA. A noninvasive blood test, EC4d, and particularly longitudinally monitoring EC4d levels, may increase surrogate ABMR testing options.

[Epidermolysis bullosa acquisita of childhood]. / Epidermolyse bulleuse acquise de l'enfant.

BACKGROUND: Epidermolysis bullosa acquisita (EBA) is a subepidermal autoimmune blistering disease characterized immunologically by autoantibodies to type VII collagen. Its occurrence in childhood is rare. Thirty-five cases have been described to date in the literature. PATIENTS AND METHODS: We report the case of an 8-year-old girl presenting blistering lesions on the cheeks, extremities and limb extension areas. The diagnosis of EBA was confirmed by histology, direct immunofluorescence of a perilesional skin biopsy specimen, indirect immunofluorescence on salt-split skin substrate and direct electron microscopy. The patient was controlled clinically under treatment with dapsone alone. DISCUSSION: This 36th childhood case of EBA presented typical clinical features, a similar prognosis and comparable treatment response to other paediatric cases. Clinical presentation is inflammatory and affects the face. As in our case, in childhood, prognosis is often better than in adults without the need for immunosuppressive agents.

[Meaning of the Quantiferon TB Gold tube test in tuberculosis screening among the hospital staff in case of very old or recent positive skin tests]. / Signification de Quantiféron TB Gold en tube en dépistage de la tuberculose parmi le personnel hospitalier en cas d'intradermoréactions positives très anciennes ou récentes.

UNLABELLED: The tuberculin skin test or PPD performed on health professionals evaluates delayed hypersensitivity to a Mycobacterium tuberculosis (Mt) antigen mixture. A very positive or increased area of induration indicates latent tuberculosis. Yet, prescribing a treatment is often difficult because of the test's poor specificity. OBJECTIVE: To determine if the T-lymphocytes of the proband exposed to specific Mt antigens to secrete interferon-gamma (IFN-gamma) can be measured; observe an immunizing response to cellular mediation improves T it this specificity? PATIENTS AND METHODS: The Department of Occupational Health at CHR of Metz performed a Quantiferon TB Gold (tube method, Cellestis) test on three groups of employees distributed according to the anteriority of a very positive IDR (>15mm). The test measures by method ELISA, the quantity of IFN-gamma secreted by the lymphocytes T collected in 1ml of total blood, after in vitro stimulation by antigens ESAT-6, CFP-10 and TB7.7. Group I is composed of 53 people (46 women [W] and 7 men [M]) and related to a recent discovery of October 2006 and June 2007, whereas group II, includes 28 of them (25W and 3M), is made of subjects with known very positive PPD for eight to 27 years. The age (41 years on average) and the sex-ratio are identical for these two groups. Group III is made of employees having made a tuberculosis there is more than 30 years. In the group I, the rate of IFN was supervised at the end of the treatment among patients who received it. RESULTS: The test Quantiferon TB Gold was positive at 15 subjects of group I (13W and 2M), that is to say 28.3%, and unspecified in one case (1.9%); positive at nine subjects of group II (9W), that is to say 32.1%. These rates of positivity are not significantly different. According to the experts consulted in group I, an antituberculosis treatment was proposed 11 times with 10 effective treatments (one refusal). A proportioning after treatment was carried out among six patients. The rate of IFN remained positive at five of the six supervised patients. This test made it possible to avoid the treatment of the 37 employees with test Quantferon TB negative Gold found over the nine months period of recruitment of group I. The choice not to treat was facilitated. CONCLUSION: The test Quantiferon indeed allows to eliminate the false positive of the skin test (1.6) so avoiding useless, expensive treatments and unwanted effects of antituberculosis medicines . On the other hand, the persistent positivity of this test 30 years after one firstly infection or after a contact does not allow to use it at present as certain control of a latent infection, unless having a negative value known about the hiring pa.

Combination of KIR and HLA gene variants augments the risk of developing birdshot chorioretinopathy in HLA-A*29-positive individuals.

Birdshot chorioretinopathy (BCR), a chronic ocular inflammatory disease with characteristic choroidal lymphocytic infiltrates, has been strongly associated with human leukocyte antigen (HLA)-A29. Although HLA-A29 occurs frequently in all populations, BCR affects only a small percentage of HLA-A29-positive Caucasians, indicating additional susceptibility factors for BCR. Discovery of HLA class I-specific killer cell immunoglobulin-like receptors (KIR) led to a series of epidemiological studies implicating KIR-HLA gene combinations in disease. Here, we characterized KIR-HLA pairs in BCR patients and controls carrying HLA-A*29 as well as controls lacking HLA-A*29. KIR-HLA pairs implicated for weak inhibition (KIR2DL2/3+HLA-C1 and KIR3DL1+HLA-Bw4(T80)) in combination with activating KIR genes associated with autoimmunity (KIR2DS2, 2DS3 and 2DS4) augment the risk of developing BCR in HLA-A*29-positive individuals. The reciprocal association of strong inhibitory pairs (KIR3DL1+HLA-Bw4(I80) and KIR2DL1+HLA-C2) in combination with those implicated in protection from infection (KIR3DS1+HLA-Bw4(I80) and KIR2DS1+HLA-C2) was observed in HLA-A*29-negative controls. These results suggest that a profound effect of KIR2DS2/S3/S4 in the absence of strong inhibition may enhance the activation of natural killer cells and T-cell subsets against intraocular self-antigens, thereby contributing to pathogenesis of BCR.

Unusual direct phycoerythrin labeling of B-cells from a splenic marginal zone lymphoma.

Flow cytometry is the most widely used method for lymphocyte subset characterization. Two types of antibodies, directly labeled with fluorochrome, are currently used for immunological diagnosis of B-cell lymphoproliferation: monoclonal antibodies against leukocyte differentiation antigens and polyclonal antibodies against immunoglobulins and light chains. In this study is described the case of a patient with an uncommon immunophenotyping of a B-cell lymphoproliferative disorder. B-cells from peripheral blood and from bone marrow reacted positively with all the tested phycoerythrin (PE)-conjugated antibodies, including the isotypic control. So we thought about a B-cell proliferation carrying a surface receptor recognizing PE: these B-cells were directly labeled with streptavidin-PE, indeed. Moreover, the immunodots from the patient were able to fix the streptavidin-PE. Finally, this unusual immunophenotyping was solved by using antibodies labeled with other fluorochromes than PE.

New HLA-DRB1*07 allele identified from microlymphocytotoxicity/SSP discrepancies.

A HLA-DRB1*07 variant allele has been identified in a cadaver kidney donor. Serological typing using monoclonal antibodies detected HLA-DR4 and HLA-DR7. HLA class II DNA typing using sequence-specific primer (PCR-SSP) polymerase chain reaction only detected DRB1*04, while sequence-specific oligonucleotide (PCR-SSO) polymerase chain reaction confirmed the presence of both DRB1*04 and DRB1*07 alleles, although two extra reactions were also found. Exon 2 of the HLA-DRB1*07 was isolated using allele-specific PCR, then cloned and sequenced. Four mutations, at positions 170 (T --> C), 171 (C --> T), 174 (C --> G), and 179 (C --> A), were observed. These mutations changed codons 57 and 60 (V --> A; S --> Y, respectively). This amino acid sequence at position 56-61 is only found in DRB1*0811.

Spontaneous retinopathy in HLA-A29 transgenic mice.

Humans who have inherited the class I major histocompatibility allele HLA-A29 have a markedly increased relative risk of developing the eye disease termed birdshot chorioretinopathy. This disease affecting adults is characterized by symmetrically scattered, small, cream-colored spots in the fundus associated with retinal vasculopathy and inflammatory signs causing damage to the ocular structures, leading regularly to visual loss. To investigate the role of HLA-A29 in this disease, we introduced the HLA-A29 gene into mice. Aging HLA-A29 transgenic mice spontaneously developed retinopathy, showing a striking resemblance to the HLA-A29-associated chorioretinopathy. These results strongly suggest that HLA-A29 is involved in the pathogenesis of this disease. Elucidation of the role of HLA-A29 should be assisted by this transgenic model.

A soluble recombinant multimeric anti-Rh(D) single-chain Fv/CR1 molecule restores the immune complex binding ability of CR1-deficient erythrocytes.

CR1 (CD35, the C3b/C4b receptor) is a widely distributed membrane glycoprotein with a unique cluster conformation on the surface of erythrocytes (E). CR1 on E is responsible for the transport of immune complexes (IC) to liver and spleen. As a cofactor of the C3b cleavage by factor I, CR1 is also a potent inhibitor of C activation and inflammation. In some diseases (systemic lupus erythematosus, hemolytic anemia, AIDS, etc.) an acquired low level of CR1 on E has been observed, leading to an impaired clearance of IC. The aim of this study was to design a heterofunctional molecule that will bind to E and restore a normal or a supranormal CR1 density on E that could mimic the unique distribution pattern of CR1 on normal E. For that purpose a new multimerizing system based on the properties of the C-terminal part of the alpha-chain of the C4 binding protein (C4bp) was used. We first produced a multimeric soluble CR1 that proved to be a better inhibitor of in vitro C activation than the monomeric form of CR1, then a heteromultimeric molecule made of CR1 and single-chain Fv anti-Rh(D) valences able to attach E and providing E with as much as a 10-fold increase in CR1 density with the same CR1 distribution pattern as native E. CR1/single-chain Fv anti-Rh(D)-treated E were able in vitro to attach as many opsonized IC as native E. These data open the way for future use of multimeric and heteromultimeric forms of soluble recombinant CR1 as therapy of IC diseases.

No quantitative relationship between CR1 and Lutheran expression on erythrocytes: In(Lu) gene product is not a common regulator of CR1 expression on erythrocytes.

The density of CR1, the C3b/C4b receptor (CD35), on erythrocytes (E) (CR1/E) is genetically determined. However, the broad distribution of CR1/E within a given genotype suggests that other genetic elements might contribute to the regulation of CR1/E. In some pathological conditions, including systemic lupus erythematosus (SLE), AIDS and hemolytic anemia, CR1 deficiency parallels the severity of the disease. When compared to healthy individuals, an accelerated decrease in CR1/E in these patients has been demonstrated, but other mechanisms interfering with CR1 density regulation during erythropoiesis might also contribute. In exceptional circumstances, CR1/E can be dramatically decreased in healthy individuals by the effect of a regulatory gene, In(Lu), that switches off various surface molecules on E, the structure genes of which are located on four different chromosomes, suggesting a transcription regulatory role for In(Lu) gene products. The hypothesis that products of this gene could physiologically regulate the surface density of all these molecules has been tested by determining Lub density on E (Lub/E) using quantitative flow cytometry. Lub antigenic sites were then compared to CR1/E among healthy individuals of the different CR1 density phenotypes, SLE patients with and without CR1 deficiency, and an exceptional SLE patient totally lacking CR1/E and reticulocytes. No quantitative relationship was found between CR1 and Lub expression in either normal or pathological conditions. These data establish that In(Lu) products are not involved in normal or pathological CR1 density regulation.

A recombinant human scFv anti-Rh(D) antibody with multiple valences using a C-terminal fragment of C4-binding protein.

Monomeric recombinant molecules prove generally unsatisfactory for in vivo use. Most biological systems are indeed multivalent either structurally, associating different chains, or functionally, when cross-linked by their ligands. Mimicking natural molecules for immune intervention implies the need for multimerizing systems to create multivalent molecules capable of interfering with physiological processing. A multivalent anti-Rh(D) recombinant protein has been designed by reconstructing the antibody binding site of a human monoclonal anti-Rh(D) antibody as a single chain Fv mini antibody, then multimerizing it by inserting at its C-terminal end the C-terminal part of the C4 binding protein (C4bp) alpha chain, which is responsible for the octamer multimerization of that molecule. This soluble multivalent recombinant molecule was functional, bound red blood cells (RBCs), agglutinated them, and did not activate complement. This demonstration model opens the way for future in vivo use of multivalent molecules associating antibody valences and other functional molecules for cell targeting, imaging, or removal of cells such as Rh(D)-positive RBCs for preventing Rh alloimmunization.

Catabolism of the human erythrocyte C3b/C4b receptor (CR1, CD35): vesiculation and/or proteolysis?

Human erythrocytes (E) react by exocytosis of membrane vesicles to various stresses including the fixation of the membrane attack complex of Complement. E from normal individuals loose a notable proportion of their initial number of surface CR1 molecules during the ageing process. An acquired decrease of CR1 on E also occurs in pathological conditions such as Systemic Lupus Erythematosus or AIDS. The present study investigated whether calcium ionophore A23187 (Ca-ion) induced vesicle formation of human E in vitro is responsible for a preferential loss of CR1 as well as whether CR1 molecules at the surface of Ca-ion treated E or vesicles are: (i) functional, (ii) native or protease degraded, or (iii) more clustered than CR1 on native E. A study of E from 137 normal individuals showed that a one-hour Ca-ion induced vesicle formation preferentially removed one third of E surface CR1. Kinetic experiments suggested that all surface CR1 could be removed from E upon longer incubation times. CR1 molecules on vesicles were still able to inhibit Complement activation, and were found in larger clusters than on native E. These data suggest that a significant part of surface CR1 molecules may be removed from E by vesicle formation during the life of E in normal individuals. This phenomenon could be exacerbated in pathological conditions.

False-negative results in anti-HLA antibody detection by Sangstat ELISA: complement dependent cytotoxicity is not yet obsolete.

Although ELISA on purified HLA molecules for detecting anti-HLA antibody (P-S ELISA) does detect some antibodies previously missed by the conventional complement dependent cytotoxicity method (C Cytotox), HLA ELISA should not fail to detect antibodies already detected by the conventional reference method to be able to make C Cytotox obsolete and to replace it in routine testing. Among 40 selected sera, 8 false-negative reactions were observed in P-S ELISA. These sera were reanalyzed blind in two laboratories and found to contain non-IgM, warm anti- HLA antibodies. These antibodies were directed in 4 cases against an HLA molecule expressed on a kidney transplant previously rejected by the subject. These antibodies, if missed, would have been potentially harmful in kidney transplantation. Thus P-S ELISA can't yet replace C Cytotox in routine anti-HLA class I detection. The cost/benefit ratio of P-S ELISA as a second-line test remains to be investigated.

Definition of the HLA-A29 peptide ligand motif allows prediction of potential T-cell epitopes from the retinal soluble antigen, a candidate autoantigen in birdshot retinopathy.

The peptide-binding motif of HLA-A29, the predisposing allele for birdshot retinopathy, was determined after acid-elution of endogenous peptides from purified HLA-A29 molecules. Individual and pooled HPLC fractions were sequenced by Edman degradation. Major anchor residues could be defined as glutamate at the second position of the peptide and as tyrosine at the carboxyl terminus. In vitro binding of polyglycine synthetic peptides to purified HLA-A29 molecules also revealed the need for an auxiliary anchor residue at the third position, preferably phenylalanine. By using this motif, we synthesized six peptides from the retinal soluble antigen, a candidate autoantigen in autoimmune uveoretinitis. Their in vitro binding was tested on HLA-A29 and also on HLA-B44 and HLA-B61, two alleles sharing close peptide-binding motifs. Two peptides derived from the carboxyl-terminal sequence of the human retinal soluble antigen bound efficiently to HLA-A29. This study could contribute to the prediction of T-cell epitopes from retinal autoantigens implicated in birdshot retinopathy.