A practical primary care approach to hematuria in children.

Although hematuria is a common finding in the unselected population of children, the approach to evaluation is quite variable. Changes in the practice of primary care medicine in the United States mandate an approach to common office problems that is practical and realistic. This review addresses three areas: the current approach to evaluation of hematuria in children, a classification of children with hematuria into four distinct and easily identified clinical categories, and the development of an algorithm for application in the primary care setting. Each category is discussed relative to the more-common etiologies of hematuria, with recommendations for appropriate evaluation as well as suggestions of an appropriate referral to the nephrologist. An algorithm is proposed that provides a practical, systematic approach to the problem without the requirement for a specific diagnosis in every patient. The proposed classification and approach to the evaluation of children with hematuria should help simplify and clarify a potentially complex process.

IgA induced activation of human mesangial cells: independent of FcalphaR1 (CD 89).

BACKGROUND: IgA nephropathy (IgAN) is characterized by deposition of polymers of IgA1 in the mesangium, accumulation of mesangial matrix and mesangial cell proliferation. Activation of the mesangial cell by IgA, via an IgA receptor, may be an initiating event in the pathology of IgAN. METHODS: We examined the ability of radiolabeled, normal serum IgA1 to bind human mesangial cells (HMC). Activation of HMC by monomeric (mIgA1) and heat aggregated IgA1 (AIgA1) was compared by Northern analysis of c-jun expression. The expression of FcalphaR1 (CD89) mRNA on our cultured mesangial cells was also assessed by Northern analysis, reverse transcription-polymerase chain reaction (RT-PCR) and flow cytometry. RESULTS: 125I-mIgA1 and 125I-AIgA1 bound to HMC in a dose-dependent, saturable manner with similar affinities. There were 1.2 x 10(6) binding sites per cell, with an affinity constant of 2.3 x 10(6) M(-1). AIgA1 induced c-jun expression in a time and dose-dependent manner (2.4-fold above baseline after 60 min exposure to AIgA1 200 microg/ml) while mIgA1 had no effect on c-jun expression. No message for CD 89 was detectable in quiescent or AIgA1 stimulated HMC by Northern analysis or RT-PCR using several primer sequences based on the sequence of U937 FcalphaR cDNA. Flow cytometry on the mesangial cells, using My 43, a monoclonal antibody to FcalphaR1 confirmed that CD 89 was not present on the cell. CONCLUSION: These results demonstrate that HMC bind mIgA1 and AIgA1 with similar affinity. However, activation of HMC requires an aggregated form of IgA1. These processes are independent of FcalphaR1, suggesting the presence of a new IgA receptor on mesangial cells.

Prompt remission of post-renal transplant nephrotic syndrome with high-dose cyclosporine.

A 2.8-year-old girl with focal segmental glomerulosclerosis had recurrence of nephrotic syndrome within 3 days of renal transplantation and the serum creatinine increased. Renal biopsy showed cellular rejection and also complete effacement of the epithelial cell foot processes. The rejection responded to methylprednisolone therapy but massive proteinuria persisted. An increase in the dose of cyclosporine A to 14 mg/kg per day was followed by immediate remission of the proteinuria. One month later, a second renal biopsy showed only focal fusion of foot processes. She remains free of proteinuria 2 years later. We propose that the higher dose of cyclosporine caused remission of the nephrotic syndrome.