International Consensus for the Dosing of Corticosteroids in Childhood-Onset Systemic Lupus Erythematosus With Proliferative Lupus Nephritis.

OBJECTIVE: To develop a standardized steroid dosing regimen (SSR) for physicians treating childhood-onset systemic lupus erythematosus (SLE) complicated by lupus nephritis (LN), using consensus formation methodology. METHODS: Parameters influencing corticosteroid (CS) dosing were identified (step 1). Data from children with proliferative LN were used to generate patient profiles (step 2). Physicians rated changes in renal and extrarenal childhood-onset SLE activity between 2 consecutive visits and proposed CS dosing (step 3). The SSR was developed using patient profile ratings (step 4), with refinements achieved in a physician focus group (step 5). A second type of patient profile describing the course of childhood-onset SLE for ≥4 months since kidney biopsy was rated to validate the SSR-recommended oral and intravenous (IV) CS dosages (step 6). Patient profile adjudication was based on majority ratings for both renal and extrarenal disease courses, and consensus level was set at 80%. RESULTS: Degree of proteinuria, estimated glomerular filtration rate, changes in renal and extrarenal disease activity, and time since kidney biopsy influenced CS dosing (steps 1 and 2). Considering these parameters in 5,056 patient profile ratings from 103 raters, and renal and extrarenal course definitions, CS dosing rules of the SSR were developed (steps 3-5). Validation of the SSR for up to 6 months post-kidney biopsy was achieved with 1,838 patient profile ratings from 60 raters who achieved consensus for oral and IV CS dosage in accordance with the SSR (step 6). CONCLUSION: The SSR represents an international consensus on CS dosing for use in patients with childhood-onset SLE and proliferative LN. The SSR is anticipated to be used for clinical care and to standardize CS dosage during clinical trials.

Mutations in ATP6V1B1 and ATP6V0A4 genes cause recessive distal renal tubular acidosis in Mexican families.

BACKGROUND: Autosomal recessive distal renal tubular acidosis (dRTA) is a rare disease characterized by a hyperchloremic metabolic acidosis with normal anion gap, hypokalemia, hypercalciuria, hypocitraturia, nephrocalcinosis, and conserved glomerular filtration rate. In some cases, neurosensorial deafness is associated. dRTA is developed during the first months of life and the main manifestations are failure to thrive, vomiting, dehydration, and anorexia. METHODS: Nine unrelated families were studied: seven children, a teenager, and an adult with dRTA. Hearing was preserved in four children. Coding regions of the genes responsible for recessive dRTA were analysed by Sanger sequencing. RESULTS: Molecular defects were found in the genes ATP6V1B1 and ATP6V0A4. We identified three homozygous variants in ATP6V1B: a frameshift mutation (p.Ile386Hisfs*56), a nucleotide substitution in exon 10 (p.Pro346Arg), and a new splicing mutation in intron 5. Three patients were homozygous for one novel (p.Arg743Trp) and one known (p.Asp411Tyr) missense mutations in the ATP6V0A4 gene. Three patients were compound heterozygous: one proband displayed two novel mutations, the frameshift mutation p.Val52Metfs*25, and a large deletion of exons 18-21; two probands showed the missense mutation p.Asp411Tyr and as a second mutation, p.Arg194Ter and c.1691+2dup, respectively. CONCLUSION: ATP6V0A4 and ATP6V1B1 genes were involved in recessive dRTA of Mexican families. All ATP6V1B1 mutations detected were homozygous and all patients developed sensorineural hearing loss (SNHL) early in infancy. ATP6V0A4 mutations were found in one infant and three children without SNHL, and in one teenager and one adult with SNHL confirming the phenotypic variability in this trait. The mutation p.Asp411Tyr detected in four Mexican families was due to a founder effect. Screening of these mutations could provide a rapid and valuable tool for diagnosis of dRTA in this population.

Dissecting the heterogeneity of macrophage activation syndrome complicating systemic juvenile idiopathic arthritis.

OBJECTIVE: To seek insights into the heterogeneity of macrophage activation syndrome (MAS) complicating systemic juvenile idiopathic arthritis (sJIA) through the analysis of a large patient sample collected in a multinational survey. METHODS: International pediatric rheumatologists and hemato-oncologists entered their patient data, collected retrospectively, in a Web-based database. The demographic, clinical, laboratory, histopathologic, therapeutic, and outcome data were analyzed in relation to (1) geographic location of caring hospital, (2) subspecialty of attending physician, (3) demonstration of hemophagocytosis, and (4) severity of clinical course. RESULTS: A total of 362 patients were included by 95 investigators from 33 countries. Demographic, clinical, laboratory, and histopathologic features were comparable among patients seen in diverse geographic areas or by different pediatric specialists. Patients seen in North America were given biologics more frequently. Patients entered by pediatric hemato-oncologists were treated more commonly with biologics and etoposide, whereas patients seen by pediatric rheumatologists more frequently received cyclosporine. Patients with demonstration of hemophagocytosis had shorter duration of sJIA at MAS onset, higher prevalence of hepatosplenomegaly, lower levels of platelets and fibrinogen, and were more frequently administered cyclosporine, intravenous immunoglobulin (IVIG), and etoposide. Patients with severe course were older, had longer duration of sJIA at MAS onset, had more full-blown clinical picture, and were more commonly given cyclosporine, IVIG, and etoposide. CONCLUSION: The clinical spectrum of MAS is comparable across patients seen in different geographic settings or by diverse pediatric subspecialists. There was a disparity in the therapeutic choices among physicians that underscores the need to establish uniform therapeutic protocols.