Preventing hyperhomocysteinemia using vitamin B6 supplementation in Givosiran-treated acute intermittent porphyria: Highlights from a case report and brief literature review.

Acute hepatic porphyrias are inherited metabolic disorders of heme biosynthesis characterized by the accumulation of toxic intermediate metabolites responsible for disabling acute neurovisceral attacks. Givosiran is a newly approved siRNA-based treatment of acute hepatic porphyria targeting the first and rate-limiting δ-aminolevulinic acid synthase 1 (ALAS1) enzyme of heme biosynthetic pathway. We described a 72-year old patient who presented with severe inaugural neurological form of acute intermittent porphyria evolving for several years which made her eligible for givosiran administration. On initiation of treatment, the patient developed a major hyperhomocysteinemia (>400 µmol/L) which necessitated to discontinue the siRNA-based therapy. A thorough metabolic analysis in the patient suggests that hyperhomocysteinemia could be attributed to a functional deficiency of cystathionine ß-synthase (CBS) enzyme induced by givosiran. Long-term treatment with vitamin B6, a cofactor of CBS, allowed to normalize homocysteinemia while givosiran treatment was maintained. We review the recently published cases of hyperhomocysteinemia in acute hepatic porphyria and its exacerbation under givosiran therapy. We also discuss the benefits of vitamin B6 supplementation in the light of hypothetic pathophysiological mechanisms responsible for hyperhomocysteinemia in these patients. Our results confirmed the importance of monitoring homocysteine metabolism and vitamin status in patients with acute intermittent porphyria in order to improve management by appropriate vitamin supplementation during givosiran treatment.

Pathogenic variants in the NLRP3 LRR domain at position 861 are responsible for a boost-dependent atypical CAPS phenotype.

BACKGROUND: Cryopyrin-associated periodic syndrome (CAPS) is associated with NLRP3 pathogenic variants, mostly located in the NACHT (neuronal apoptosis inhibitor protein, MHC class 2 transcription activator, incompatibility locus protein from Podospora anserina, telomerase-associated protein) domain. Cold-induced urticarial rash is among the main clinical features. However, this study identified a series of 14 patients with pathogenic variants of the Y861 residue (p.Tyr861) of the LRR domain of NLRP3 and minimal prevalence of cold-induced urticarial rash. OBJECTIVES: This study aimed to address a possible genotype/phenotype correlation for patients with CAPS and to investigate at the cellular levels the impact of the Y861C substitution (p.Tyr861Cys) on NLRP3 activation. METHODS: Clinical features of 14 patients with CAPS and heterozygous substitution at position 861 in the LRR domain of NLRP3 were compared to clinical features of 48 patients with CAPS and pathogenic variants outside the LRR domain of NLRP3. IL-1ß secretion by PBMCs and purified monocytes from patients and healthy donors was evaluated following LPS and monosodium urate crystal stimulation. RESULTS: Patients with substitution at position 861 of NLRP3 demonstrated a higher prevalence of sensorineural hearing loss while being less prone to skin urticarial. In contrast to patients with classical CAPS, cells from patients with a pathogenic variant at position 861 required an activation signal to secrete IL-1ß but produced more IL-1ß during the early and late phase of secretion than cells from healthy donors. CONCLUSIONS: Pathogenic variants of Y861 of NLRP3 drive a boost-dependent oversecretion of IL-1ß associated with an atypical CAPS phenotype.

Invasive bone and joint infections from the French Scedosporiosis/lomentosporiosis Observational Study (SOS) cohort: no mortality with long-term antifungal treatment and surgery.

Little is known about localized osteoarticular Scedosporiosis (LOS). Most data come from case reports and small case series. Here we present an ancillary study of the nationwide French Scedosporiosis Observational Study (SOS), describing 15 consecutive cases of LOS diagnosed between January 2005 and March 2017. Adult patients diagnosed with LOS defined by osteoarticular involvement without distant foci reported in SOS were included. Fifteen LOS were analyzed. Seven patients had underlying disease. Fourteen patients had prior trauma as potential inoculation. Clinical presentation was arthritis (n = 8), osteitis (n = 5), and thoracic wall infection (n = 2). The most common clinical manifestation was pain (n = 9), followed by localized swelling (n = 7), cutaneous fistulization (n = 7), and fever (n = 5). The species involved were Scedosporium apiospermum (n = 8), S. boydii (n = 3), S. dehoogii (n = 1), and Lomentospora prolificans (n = 3). The species distribution was unremarkable except for S. boydii, which was associated with healthcare-related inoculations. Management was based on medical and surgical treatment for 13 patients. Fourteen patients received antifungal treatment for a median duration of 7 months. No patients died during follow-up. LOS exclusively occurred in the context of inoculation or systemic predisposing factors. It has a non-specific clinical presentation and is associated with an overall good clinical outcome, provided there is a prolonged course of antifungal therapy and adequate surgical management.

Localized osteoarticular scedosporiosis mostly occurs following direct inoculation. Management was most often based on voriconazole therapy and concomitant surgery. Unlike other invasive scedosporiosis, no patient died during follow-up.

Scedosporiosis/lomentosporiosis observational study (SOS): Clinical significance of Scedosporium species identification.

Scedosporiosis/lomentosporiosis is a devastating emerging fungal infection. Our objective was to describe the clinical pattern and to analyze whether taxonomic grouping of the species involved was supported by differences in terms of clinical presentations or outcomes. We retrospectively studied cases of invasive scedosporiosis in France from 2005 through 2017 based on isolates characterized by polyphasic approach. We recorded 90 cases, mainly related to Scedosporium apiospermum (n = 48), S. boydii/S. ellipsoideum (n = 20), and Lomentospora prolificans (n = 14). One-third of infections were disseminated, with unexpectedly high rates of cerebral (41%) and cardiovascular (31%) involvement. In light of recent Scedosporium taxonomic revisions, we aimed to study the clinical significance of Scedosporium species identification and report for the first time contrasting clinical presentations between infections caused S. apiospermum, which were associated with malignancies and cutaneous involvement in disseminated infections, and infections caused by S. boydii, which were associated with solid organ transplantation, cerebral infections, fungemia, and early death. The clinical presentation of L. prolificans also differed from that of other species, involving more neutropenic patients, breakthrough infections, fungemia, and disseminated infections. Neutropenia, dissemination, and lack of antifungal prescription were all associated with 3-month mortality. Our data support the distinction between S. apiospermum and S. boydii and between L. prolificans and Scedosporium sp. Our results also underline the importance of the workup to assess dissemination, including cardiovascular system and brain.

Scedosporiosis/lomentosporiosis is a devastating emerging fungal infection. Our objective was to describe the clinical pattern and to analyze whether taxonomic grouping of the species involved was supported by differences in terms of clinical presentations or outcomes.

Limbic encephalitis as a relapse of Whipple's disease with digestive involvement and spondylodiscitis.

INTRODUCTION: Many clinical manifestations can be related to Tropheryma whipplei infection. CASE REPORT: We report a Tropheryma whipplei limbic encephalitis developed as a relapse of classical Whipple's disease. DISCUSSION: This case is to the best of our knowledge the first proof of the effective brain-blood barrier crossing of both doxycycline and hydroxychloroquine as demonstrated by direct concentration monitoring on brain biopsy.

Gamma delta T cell expansion in Whipple's disease with muscular granulomatous vasculitis.

Whipple's disease usually presents as chronic joint pain followed by digestive manifestations. However, many different presentations have been described in the literature. We report here the first proven case of muscular vasculitis related to Whipple's disease, associated with an expansion of circulating activated γδ T lymphocytes.

Genetic, immunological, and clinical features of patients with bacterial and fungal infections due to inherited IL-17RA deficiency.

Chronic mucocutaneous candidiasis (CMC) is defined as recurrent or persistent infection of the skin, nails, and/or mucosae with commensal Candida species. The first genetic etiology of isolated CMC-autosomal recessive (AR) IL-17 receptor A (IL-17RA) deficiency-was reported in 2011, in a single patient. We report here 21 patients with complete AR IL-17RA deficiency, including this first patient. Each patient is homozygous for 1 of 12 different IL-17RA alleles, 8 of which create a premature stop codon upstream from the transmembrane domain and have been predicted and/or shown to prevent expression of the receptor on the surface of circulating leukocytes and dermal fibroblasts. Three other mutant alleles create a premature stop codon downstream from the transmembrane domain, one of which encodes a surface-expressed receptor. Finally, the only known missense allele (p.D387N) also encodes a surface-expressed receptor. All of the alleles tested abolish cellular responses to IL-17A and -17F homodimers and heterodimers in fibroblasts and to IL-17E/IL-25 in leukocytes. The patients are currently aged from 2 to 35 y and originate from 12 unrelated kindreds. All had their first CMC episode by 6 mo of age. Fourteen patients presented various forms of staphylococcal skin disease. Eight were also prone to various bacterial infections of the respiratory tract. Human IL-17RA is, thus, essential for mucocutaneous immunity to Candida and Staphylococcus, but otherwise largely redundant. A diagnosis of AR IL-17RA deficiency should be considered in children or adults with CMC, cutaneous staphylococcal disease, or both, even if IL-17RA is detected on the cell surface.