Atypical hemolytic uremic syndrome (aHUS) may be associated with mutations in the C-terminal of factor H (FH).

We investigated the phenotypic expression of factor H mutations in two patients with atypical hemolytic uremic syndrome (HUS). Factor H in serum was assayed by rocket immunoelectrophoresis, immunoblotting, and double immunodiffusion and in tissue by immunohistochemistry. Functional activity was analyzed by hemolysis of sheep erythrocytes and binding to endothelial cells. A homozygous mutation in complement control protein (CCP) domain 10 of factor H was identified in an adult man who first developed membranoproliferative glomerulonephritis and later HUS. C3 levels were very low. The patient had undetectable factor H levels in serum and a weak factor H 150 kDa band. Double immunodiffusion showed partial antigenic identity with factor H in normal serum owing to the presence of factor H-like protein 1. Strong specific labeling for factor H was detected in glomerular endothelium, mesangium and in glomerular and tubular epithelium as well as in bone marrow cells. A heterozygous mutation in CCP 20 of factor H was found in a girl with HUS. C3 levels were moderately decreased at onset. Factor H levels were normal and a normal 150 kDa band was present. Double immunodiffusion showed antigenic identity with normal factor H. Factor H labeling was minimal in the renal cortex. Factor H dysfunction was demonstrated by increased sheep erythrocyte hemolysis and decreased binding to endothelial cells. In summary, two different factor H mutations associated with HUS were examined: in one, factor H accumulated in cells, and in the other, membrane binding was reduced.

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Individuals with focal segmental glomerulosclerosis (FSGS) are at risk for recurrence of disease following renal transplantation. The rate of recurrence has been estimated to range from 20% to 30%. The factors associated with an increased probability of recurrence are not known, although the rapidity of progression of disease, age at onset, and the presence of diffuse mesangial proliferation in the native kidney have all been implicated. We analyzed the data from 35 patients with FSGS who received 37 renal transplants at this institution between October 1968 and December 1997. Recurrence was diagnosed by the development of nephrotic-range proteinuria and a transplant biopsy compatible with the diagnosis. Sixteen recurrences were noted, with an overall recurrence rate of 43%. The risk of recurrence was associated with the use of antilymphocytic serum (ALS) for initial induction therapy; being 11% in those who received no induction therapy versus 53% in those who received ALS. Furthermore, in the latter group, the rate of recurrence was 88% in those who received antithymocyte globulin (ATGAM) versus 40% in those who received Minnesota antilymphocytic globulin. Factors such as race, sex, age at time of diagnosis, rapidity of progression to end-stage renal disease (ESRD), response to alkylating agents and/or cyclosporin therapy prior to ESRD, age at time of transplant, donor source, and triple or double immunosuppressive therapy did not appear to have an effect on the rate of recurrence. We conclude that induction therapy with ALS at time of transplantation increases the risk of recurrence of FSGS following renal transplantation.

Guidelines for the treatment of Lyme arthritis were published by the Infectious Diseases Society of America in 2006 and recommended oral doxycycline for initial therapy. We report here the case of a young girl treated with intravenous ceftriaxone who subsequently developed drug-induced autoimmune hemolytic anemia and renal failure. Her severe sequelae highlight the importance of antimicrobial stewardship. We review here the goals of antimicrobial stewardship and several strategies for achieving them. In addition, we briefly discuss the rare adverse drug event experienced by our patient.