Childhood-Onset Lupus Nephritis in the Childhood Arthritis and Rheumatology Research Alliance Registry: Short-Term Kidney Status and Variation in Care

OBJECTIVE

The goal was to characterize short-term kidney status and describe variation in early care utilization in a multicenter cohort of patients with childhood-onset systemic lupus erythematosus (cSLE) and nephritis.

METHODS

We analyzed previously collected prospective data from North American patients with cSLE with kidney biopsy-proven nephritis enrolled in the Childhood Arthritis and Rheumatology Research Alliance (CARRA) Registry from March 2017 through December 2019. We determined the proportion of patients with abnormal kidney status at the most recent registry visit and applied generalized linear mixed models to identify associated factors. We also calculated frequency of medication use, both during induction and ever recorded.

RESULTS

We identified 222 patients with kidney biopsy-proven nephritis, with 64% class III/IV nephritis on initial biopsy. At the most recent registry visit at median (interquartile range) of 17 (8-29) months from initial kidney biopsy, 58 of 106 patients (55%) with available data had abnormal kidney status. This finding was associated with male sex (odds ratio [OR] 3.88, 95% confidence interval [95% CI] 1.21-12.46) and age at cSLE diagnosis (OR 1.23, 95% CI 1.01-1.49). Patients with class IV nephritis were more likely than class III to receive cyclophosphamide and rituximab during induction. There was substantial variation in mycophenolate, cyclophosphamide, and rituximab ever use patterns across rheumatology centers.

CONCLUSION

In this cohort with predominately class III/IV nephritis, male sex and older age at cSLE diagnosis were associated with abnormal short-term kidney status. We also observed substantial variation in contemporary medication use for pediatric lupus nephritis between pediatric rheumatology centers. Additional studies are needed to better understand the impact of this variation on long-term kidney outcomes.

Intraarticular steroids as DMARD-sparing agents for juvenile idiopathic arthritis flares: Analysis of the Childhood Arthritis and Rheumatology Research Alliance Registry

BACKGROUND

Children with juvenile idiopathic arthritis (JIA) who achieve a drug free remission often experience a flare of their disease requiring either intraarticular steroids (IAS) or systemic treatment with disease modifying anti-rheumatic drugs (DMARDs). IAS offer an opportunity to recapture disease control and avoid exposure to side effects from systemic immunosuppression. We examined a cohort of patients treated with IAS after drug free remission and report the probability of restarting systemic treatment within 12 months.

METHODS

We analyzed a cohort of patients from the Childhood Arthritis and Rheumatology Research Alliance (CARRA) Registry who received IAS for a flare after a period of drug free remission. Historical factors and clinical characteristics and of the patients including data obtained at the time of treatment were analyzed.

RESULTS

We identified 46 patients who met the inclusion criteria. Of those with follow up data available 49% had restarted systemic treatment 6 months after IAS injection and 70% had restarted systemic treatment at 12 months. The proportion of patients with prior use of a biologic DMARD was the only factor that differed between patients who restarted systemic treatment those who did not, both at 6 months (79% vs 35%, p < 0.01) and 12 months (81% vs 33%, p < 0.05).

CONCLUSION

While IAS are an option for all patients who flare after drug free remission, it may not prevent the need to restart systemic treatment. Prior use of a biologic DMARD may predict lack of success for IAS. Those who previously received methotrexate only, on the other hand, are excellent candidates for IAS.

Social determinants of health influence disease activity and functional disability in Polyarticular Juvenile Idiopathic Arthritis

BACKGROUND

Social determinants of health (SDH) greatly influence outcomes during the first year of treatment in rheumatoid arthritis, a disease similar to polyarticular juvenile idiopathic arthritis (pJIA). We investigated the correlation of community poverty level and other SDH with the persistence of moderate to severe disease activity and functional disability over the first year of treatment in pJIA patients enrolled in the Childhood Arthritis and Rheumatology Research Alliance Registry.

METHODS

In this cohort study, unadjusted and adjusted generalized linear mixed effects models analyzed the effect of community poverty and other SDH on disease activity, using the clinical Juvenile Arthritis Disease Activity Score-10, and disability, using the Child Health Assessment Questionnaire, measured at baseline, 6, and 12 months.

RESULTS

One thousand six hundred eighty-four patients were identified. High community poverty (≥20% living below the federal poverty level) was associated with increased odds of functional disability (OR 1.82, 95% CI 1.28-2.60) but was not statistically significant after adjustment (aOR 1.23, 95% CI 0.81-1.86) and was not associated with increased disease activity. Non-white race/ethnicity was associated with higher disease activity (aOR 2.48, 95% CI: 1.41-4.36). Lower self-reported household income was associated with higher disease activity and persistent functional disability. Public insurance (aOR 1.56, 95% CI 1.06-2.29) and low family education (aOR 1.89, 95% CI 1.14-3.12) was associated with persistent functional disability.

CONCLUSION

High community poverty level was associated with persistent functional disability in unadjusted analysis but not with persistent moderate to high disease activity. Race/ethnicity and other SDH were associated with persistent disease activity and functional disability.

Characterization of molecular defects in isovaleryl-CoA dehydrogenase in patients with isovaleric acidemia

Isovaleryl-CoA dehydrogenase (IVD) is a homotetrameric mitochondrial flavoenzyme which catalyzes the conversion of isovaleryl-CoA to 3-methylcrotonyl-CoA. PCR of IVD genomic and complementary DNA was used to identify mutations occurring in patients with deficiencies in IVD activity. Western blotting, in vitro mitochondrial import, prokaryotic expression, and kinetic studies of IVD mutants were conducted to characterize the molecular defects caused by the amino acid replacements. Mutations leading to Arg21Pro, Asp40Asn, Ala282Val, Cys328Arg, Val342Ala, Arg363Cys, and Arg382Leu replacements were identified. Western blotting of fibroblast extracts and/or in vitro mitochondrial import experiments indicate that the seven precursor IVD mutant peptides, and a previously identified IVD Leu13Pro mutant, are synthesized and imported into mitochondria. While the IVD Leu13Pro, Arg21Pro, and Cys328Arg mutant peptides are rapidly degraded following mitochondrial import, the other mutant peptides exhibit greater mitochondrial stability, though less than the wild-type enzyme. Active IVD Ala282Val, Val342Ala, Arg363Cys, and Arg382Leu mutants were less stable than wild type when produced in Escherichia coli. The Km values of purified IVD Ala282Val, Val342Ala, and Arg382Leu mutants are 27.0, 2. 8, and 6.9 microM isovaleryl-CoA, respectively, compared to 3.1 microM for the wild type, using the electron-transfer flavoprotein (ETF) fluorescence quenching assay. The catalytic efficiency per mole of FAD content of these three mutants is 4.8, 17.0, and 17.0 microM-1*min-1, respectively, compared to 170 microM-1*min-1 for wild type.

Effects of spermine and its cytotoxic analogs on nucleosome formation on topologically stressed DNA in vitro

We investigated the effects of the polyamine spermine and two of its cytotoxic analogs 1,11-bis(ethylamino)-4,8-diazaundecane (BE-3-3-3) and 1,19-bis(ethylamino)-5,10,15-tirazanonadecane (BE-4-4-4-4) on the formation of nucleosomes on negatively and positively supercoiled DNA in vitro. Histones H2A, H2B, H3 and H4 were reconstituted onto DNA to form nucleosomes and the polyamines were added either before or after histone addition. The structural state of the nucleosome was monitored by analyzing the DNA topoisomers that were present after topoisomerase I treatment. Although polyamines induced DNA aggregation to various degrees. high concentrations of topoisomerase I were able to relax the aggregated DNA and the helical pitch was found to be unaltered in the aggregates. When histones were associated with negatively coiled DNA, the polyamine-induced aggregation did not alter nucleosome structure. The induced aggregate did inhibit nucleosomal transitions when examined on positively coiled DNA. BE-4-4-4-4 was most effective and BE-3-3-3 least effective. These analogs were also extremely effective in inhibiting histone deposition onto DNA. A potential mechanism for the action of these analogs is both to inhibit histone deposition during DNA replication and also disrupt nucleosomal dynamics due to aberrant chromatin condensation. These results also suggest that BE-4-4-4-4 and BE-3-3-3 may produce their cytotoxic effect through slightly different mechanisms.