However, it should be noted that all babies were born preterm [10]. may cause reduced innate immunity which could render newborns more susceptible to infections. in stool were Roxatidine acetate hydrochloride negative. A renal biopsy showed 7 glomeruli without fresh thrombotic material, but ischemic damage of glomeruli and tubuli. Vessels showed increased wall thickening without thrombotic material, which may indicate weak thrombotic microangiopathy, and immunofluorescence was negative. Genetic findings Genetic workup revealed no mutations located Roxatidine acetate hydrochloride in the genes for complement factor H, complement factor I, and membrane cofactor protein. The patient had a homozygous deletion of exon 3C6 in the complement factor H related gene 1 (CFHR1), and a heterozygous deletion of exon 4C6 in the complement factor H related gene 3 (CFHR3). Treatment of atypical hemolytic uremic syndrome and chronic kidney disease As the case dates back several years, daily plasmapheresis had been started (i.e., plasma exchange of 1 1.0 plasma volume every day), resulting in attenuation of the hemolytic anemia whereas renal function did not recover. Nowadays administration of eculizumab may be considered [3C7]. Hemodialysis treatment was continued until 20?months later when she received a crossmatch negative AB0-compatible, nonrelated living donor kidney transplant. The immunosuppressive regimen included basiliximab, tacrolimus, and mycophenolate mofetil, and immediate transplant function was unremarkable. However, rising plasma creatinine levels were observed after transplantation together with hemolytic anemia and thrombocytopenia, indicating a relapse of atypical hemolytic uremic syndrome. One biopsy obtained 1?week after transplantation showed 17 glomeruli without thrombotic material, there were no signs for rejection, g0-1v0i1-3?t0-1ah0ptc0. Another biopsy obtained 6?weeks after transplantation showed 7 glomeruli without thrombotic material. Vessels showed increased wall thickening without thrombotic material, and immunofluorescence was positive for C3 and Acta1 C4d. There were no signs for rejection, g1v0i1t0ah1ptc0. Although tacrolimus was discontinued, whereas prednisolone, plasmapheresis, and eculizumab were started, we observed a progressive deterioration of transplant function and three months later hemodialysis treatment was resumed because of uremic symptoms. Treatment with eculizumab during pregnancy The patient performed home dialysis 6?days per week for 5?h using a biocompatible membrane. Ten months later, she got pregnant. At gestational age 11?+?1 a relapse of the hemolytic anemia and thrombocytopenia was observed (hemoglobin 4.8?mmol/L, haptoglobine levels less than 0.08?g/L, platelet count 83 per nL). Intravenous eculizumab (1200?mg every other week) was started and given throughout pregnancy. The pregnancy was followed closely with repeated ultrasound monitoring growth and fetal blood flows. Intrauterine growth retardation was diagnosed due to suspected fetal distress, a healthy male index baby was delivered by cesarean section in week 34?+?2. An eculizumab infusion was given 2?h before cesarean section. Hemodialysis and eculizumab treatment were continued in the mother and follow ups in both baby and mother Roxatidine acetate hydrochloride after 12?months were uneventful. Complement C3 deposition is not affected by eculizumab In the mothers blood, in index newborns umbilical cord vein blood (obtained after delivery, i.e., 2?h after the last eculizumab infusion), and in blood three weeks after birth we measured deposition of complement C3 and C9 using the Palarasah-Nielsen-ELISA as previously described [8, 9]. Fig.?1 shows the capacities of three complement pathways as determined by complement C3 deposition in the Palarasah-Nielsen-ELISA. Complement C3 deposition was similar in umbilical cord blood from control newborns and index child. The control group consisted of five pre-term (born in gestational week 35C36) boys born to healthy mothers. The lectin pathway activity was abrogated in the index baby as well as the control newborns. Open in a separate window Fig. 1 Complement C3 deposition in index newborn and mother. Complement C3 deposition after activation of the classic, alternative, and lectin pathway in umbilical cord blood from preterm new Roxatidine acetate hydrochloride born controls Roxatidine acetate hydrochloride (box and whiskers plot), umbilical cord blood from the index newborn, in blood from the mother treated with eculizumab, and in blood from the index newborn at 3?weeks. Results are given for the deposition of complement C3 using the Palarasah-Nielsen-ELISA [9] Eculizumab reduces membrane attack complex formation in the index newborn Complement C9 deposition which occurs downstream of eculizumab inhibition is shown in Fig.?2. As expected in the mothers blood, complement C9 deposition induced by activation of the classical pathway was completely abolished (0% compared to 59 to 130% in healthy adults) [9]. It should be noted that complement C9 deposition induced by activation of the classical pathway was almost completely abrogated in umbilical cord blood from the index newborn (2%), whereas newborn controls showed a median of 70%. The control group consisted of five pre-term (born in gestational week 35C36) boys born to healthy mothers. Complement C9 deposition normalized in the index child after 3?weeks. Furthermore, in vitro administration of 100?g/mL complement factor C5 increased complement.