Inborn errors of metabolism underlying primary immunodeficiencies

A number of inborn errors of metabolism (IEM) have been shown to result in predominantly immunologic phenotypes, manifesting in part as inborn errors of immunity. These phenotypes are mostly caused by defects that affect the (i) quality or quantity of essential structural building blocks (e.g., nucleic acids, and amino acids), (ii) cellular energy economy (e.g., glucose metabolism), (iii) post-translational protein modification (e.g., glycosylation) or (iv) mitochondrial function. Presenting as multisystemic defects, they also affect innate or adaptive immunity, or both, and display various types of immune dysregulation. Specific and potentially curative therapies are available for some of these diseases, whereas targeted treatments capable of inducing clinical remission are available for others. We will herein review the pathogenesis, diagnosis, and treatment of primary immunodeficiencies (PIDs) due to underlying metabolic disorders.     

Students’ perspectives on research and assessment of a model template designed to guide beginners in research in a medical school in Cameroon

Background

Research activities for medical students and residents (trainees) are expected to serve as a foundation for the acquisition of basic research skills. Some medical schools therefore recommend research work as partial requirement for certification. However medical trainees have many difficulties concerning research, for which reason potential remedial strategies need to be constantly developed and tested. The views of medical trainees are assessed followed by their use and appraisal of a novel “self-help” tool designed for the purposes of this study with potential for improvement and a wider application.

Methods

This study was a cross-sectional survey of volunteering final-year medical students and residents of a medical school in Cameroon.

Results

This study surveyed the opinions of a total of 120 volunteers of which 82 (68%) were medical students. Three out of 82 (4%) medical students reported they had participated in research activities with a publication versus 10 out of 38 residents (26%). The reported difficulties in research for these trainees included referencing of material (84%), writing a research proposal (79%), searching for literature (73%) and knowledge of applicable statistical tests (72%) amongst others. All participants declared the “self-help” tool was simple to use, guided them to think and better understand their research focus.

Conclusion

Medical trainees require much assistance on research and some “self-help” tools such as the template used in this study might be a useful adjunct to didactic lectures.

     

Long-term effectiveness and safety of interleukin-1 receptor antagonist (anakinra) in Schnitzler's syndrome: A french multicenter study

The aim of this study is to assess the long-term effectiveness and safety of IL1Ra in Schnitzler syndrome (SchS). Between 2010 and 2012, we performed a nationwide survey among French internal medicine departments to identify SchS patients. We retrospectively analyzed the long-term efficacy and safety of IL1Ra and the outcome of patients that did not receive this treatment. Forty-two patients were included in the study, 29 of whom received IL1Ra. The mean age at disease onset was 59.9 years. Disease manifestations included urticaria (100%), fever (76%), bone/joint pain (86%), bone lesions (76%), anemia (67%), and weight loss (60%). The monoclonal gammopathy was overwhelmingly IgM kappa (83%). The mean follow-up was 9.5 years (range: 1.6-35). Two patients developed Waldenström's macroglobulinemia and one developed AA amyloidosis. All of the 29 patients who received IL1Ra responded dramatically. After a median follow-up of 36 months (range: 2-79), the effectiveness remained unchanged. All patients remained on anti-IL-1 therapy. Twenty-four patients (83%) went into complete remission and five (17%) into partial remission. Three patients experienced grade 3-4 neutropenia. Six patients developed severe infections. No lymphoproliferative diseases occurred while on IL1Ra. When last seen, all patients without anakinra had an active disease with variable impact on their quality of life. Their median corticosteroids dosage was 6 mg/d (range: 5-25). IL1Ra is effective in SchS, with a sharp corticosteroid-sparing effect. Treatment failures should lead to reconsider the diagnosis. Long-term follow-up revealed no loss of effectiveness and a favorable tolerance profile. The long-term effects on the risk of hemopathy remain unknown.     

Streptococcal infection as possible trigger for dense deposit disease (C3 glomerulopathy)

Dense deposit disease (DDD, formerly known as membranoproliferative glomerulonephritis (MPGN) type II) is a subtype of C3 glomerulopathy (C3G). Electron-dense deposits in the glomerular basement membrane characterize this glomerulonephritis. DDD typically presents with a nephritic syndrome that progresses to end-stage renal failure in 50 % of patients despite treatment. The pathogenic basis of DDD is uncontrolled activation of the alternative complement cascade although the potential triggering events that precipitate the development of complement dysregulation are typically unknown. There are isolated reports of an apparent association between streptococcal infection and DDD, as well as with MPGN types I and III. However, this association has not been deemed compelling, perhaps because so few cases have been reported or because of a current lack of evidence for a plausible hypothesis to connect a streptococcal infection with subsequent disease. In this report, we describe two patients with DDD who definitely had an antecedent streptococcal infection with the phenotype of acute post-streptococcal glomerulonephritis and whose initial kidney biopsy findings on light microscopy were indistinguishable from acute post-streptococcal glomerulonephritis. These patients had additional points of interest: recurrence of gross hematuria with recurrent streptococcal infections, slowly progressive course, persistently low serum C3 concentration, positive C3 nephritic factor, and positive risk alleles in the complement factor H (CFH) gene. Conclusion: We suggest that streptococcal infection may trigger DDD in individuals genetically predisposed by virtue of a disorder in complement regulation.