Rituximab-induced IgG hypogammaglobulinemia in children with nephrotic syndrome and normal pre-treatment IgG values

BACKGROUND In paediatric patients with complicated nephrotic syndrome(NS), rituximab(RTX) administration can induce persistent IgG hypogammaglobulinemia among subjects showing low basal immunoglobulin G(IgG) levels.AIM To evaluate the effect of RTX on IgG levels and infections in patients with complicated NS and normal basal IgG levels.METHODS We consecutively enrolled all patients with complicated NS and normal basal IgG levels undergoing the first RTX infusion from January 2008 to January 2016. Basal IgG levels were dosed after 6 wk of absent proteinuria and with a maximal interval of 3 mo before RTX infusion. The primary outcome was the onset of IgG hypogammaglobulinemia during the follow-up according to the IgG normal values for age [mean ± standard deviation(SD)].RESULTS We enrolled 20 patients with mean age at NS diagnosis of 4.2 ± 3.3 years. The mean age at the first RTX infusion was 10.9 ± 3.5 years. Eleven out of twenty patients(55%) developed IgG hypogammaglobulinemia. None of these patients showed severe or recurrent infections. Only one patient suffered from recurrent acute otitis media and underwent substitutive IgG infusion. Three patients undergoing only the two "starting doses" experienced normalization of IgG levels. Using Kaplan-Meier analysis, the cumulative proportion of patients free of IgG hypogammaglobulinemia was 57.8% after the first RTX dose, 51.5% after the third dose, 44.1% after the fourth dose, and 35.5% after the fifth dose.CONCLUSION RTX can induce IgG hypogammaglobulinemia in patients with pre-RTX IgG normal values. None of the treated patients showed severe infections.

Dehydrated patient without clinically evident cause:A case report

BACKGROUND Patients affected by cystic fibrosis can present with metabolic alkalosis such as Bartter's syndrome.In this case report we want to underline this differential diagnosis and we aimed focusing on the suspect of cystic fibrosis,also in case of a negative newborn screening.CASE SUMMARY In a hot August–with a mean environmental temperature of 36℃–an 8-mo-old female patient presented with severe dehydration complicated by hypokalemic metabolic alkalosis,in absence of fever,diarrhea and vomiting.Differential diagnosis between cystic fibrosis and tubulopathies causing metabolic alkalosis(Bartter's Syndrome)was considered.We started intravenous rehydration with subsequent improvement of clinical conditions and serum electrolytes normalization.We diagnosed a mild form of cystic fibrosis(heterozygous mutations:G126 D and F508 del in the cystic fibrosis transmembrane conductance regulator gene).The trigger factor of this condition had been heat exposure.CONCLUSION When facing a patient with hypokalemic metabolic alkalosis,cystic fibrosis presenting with Pseudo-Bartter's syndrome should be considered in the differential diagnosis,even if the newborn screening was negative.