Altered immune response in organic acidemia.

BACKGROUND: Most patients with organic acidemia suffer from recurrent infections. Although neutropenia has been reported in multiple studies, other components of the immune system have not been evaluated thoroughly. This study was conducted to assess the immune status of patients with organic acidemia (OA). METHODS: Thirty-three patients with OA who were followed up in Istanbul University-Cerrahpasa, Cerrahpasa School of Medicine, Nutrition and Metabolism Department and a total of 32 age- and sex-matched healthy controls were enrolled to the study. The demographic and clinical data were recorded retrospectively from patient files. Complete blood counts, immunoglobulins, and lymphocyte immunophenotyping were recorded prospectively in a symptom- (infection-) free period. RESULTS: Of the 33 patients enrolled to the study, 21 (88%) were diagnosed with methylmalonic acidemia, 10 (33%) with propionic acidemia, and two (6.6%) with isovaleric acidemia. The mean age of the patients with OA and healthy subjects were 5.89 ± 4.11 years and 5.34 ± 4.36, respectively (P = 0.602). Twenty-nine (88%) of the patients had experienced frequent hospital admission, 13 (39%) were admitted to pediatric intensive care unit, and 18 (55%) suffered from sepsis. Naïve helper T cells and recent thymic emigrants were significantly lower in OAs (P < 0.001). Various defects in humoral immunity have also been documented including memory B cells and immunoglobulins. CONCLUSIONS: Patients with OAs may show adaptive immune defects rendering them susceptible to infections. Metabolic reprogramming based on nutritional modifications may be a promising therapeutic option in the future.

Anti-nuclear antibody testing in children: How much is really necessary?

BACKGROUND: Anti-nuclear antibody (ANA) testing is most commonly ordered by general pediatricians to evaluate children with musculoskeletal system complaints. Given the limited utility of the test, we aimed to estimate the effectiveness of ordering ANA testing in childhood. METHODS: Children referred to our department to be examined due to positive ANA findings between 2008 and 2020 were included in the study. Those with less than one-year follow-up period, those with previously known rheumatic or autoimmune disease, and those diagnosed as an autoimmune and/or rheumatic disease at the first visit were excluded. Data were obtained from their medical records, retrospectively. The parents of all of the patients were called via phone, data were verified, and missing information was collected. RESULTS: Three hundred and fifty-eight patients (230 females) were eligible for the study. The median age of positive ANA findings was 9.31 (1.3-17.86) years and the median follow-up duration was 4.85 (1-11.91) years. Most of the patients had no underlying disease (n = 337, 94.1%). The most common reason for ordering ANA testing was to evaluate musculoskeletal system symptoms (n = 225, 62.8%). None of our patients referred to us due to positive ANA findings developed any autoimmune conditions or ANA associated rheumatic disease. Hypermobility syndrome is the most common final diagnosis among our ANA-positive patients. CONCLUSION: We suggest that instead of using it as a screening tool, ANA testing should be performed only if there is a strong suspicion of autoimmune diseases or certain rheumatic conditions, such as systemic lupus erythematosus.