Anthony G Morgan

Erythropoietin and renal function in sickle-cell disease.

The relation between haemoglobin concentration, creatinine clearance, and the serum concentration of erythropoiesis-stimulating factor were assessed in 31 patients with homozygous sickle-cell disease. Haemoglobin concentrations fell significantly with decreasing creatinine clearance (r = 0.58, p less than 0.001) and were positively correlated with the concentration of erythropoiesis-stimulating factor (r = 0.65, p less than 0.001). These observations suggest that erythropoietin concentration is the factor limiting production of red cells in sickle-cell disease with renal insufficiency and have implications for treatment.

Serum urate concentrations in homozygous sickle cell disease

Serum and urinary urate concentrations were studied in 44 patients with homozygous sickle cell (SS) disease, and in 27 controls with normal haemoglobin. Hyperuricaemia (>0·39 mmol/l (6·5 mg/100 ml)) occurred in 41% of SS patients and inversely correlated with renal urate clearance but not with indices of bone marrow turnover. Higher serum urate concentrations occurred in patients with proteinuria, probably due to associated tubular damage. Higher serum urate concentrations and lower urate clearance occurred in males compared to females.

Glomerular function and hyperuricaemia in sickle cell disease.

Renal insufficiency is common in adults with homozygous sickle cell disease, and the contribution of glomerular failure to the hyperuricaemia which is often a feature of the disease has therefore been investigated. In a study of 64 patients between the ages of 15 and 66, serum urate concentration was dependent on renal urate clearance and also on creatinine clearance. The relation between serum urate and creatinine clearance was abnormal in patients with sickle cell disease and it is suggested that this might be caused by high single nephron glomerular filtration rates. Both the amount of urate excreted per millilitre of glomerular filtrate and the fractional excretion of urate increased with falling creatinine clearance, suggesting that the ability to increase tubular urate secretion was preserved. Patients with extensive tubular disease as shown by tubular proteinuria had serum urate concentrations which were not significantly different from those of age and sex matched non-proteinuric patients. Evidence that renal tubular disease interferes with urate secretion and causes hyperuricaemia in patients with sickle cell disease needs to be reinterpreted in the light of these findings.

Membranous Glomerulonephropathy with Crescents in Systemic Lupus erythematosus

Over a 2-year period percutaneous renal biopsies were carried out on 23 patients with systemic lupus nephritis. When classified by immunofluorescence, and light and electron microscopy, 4 patients had mesangial disease, 1 had focal and segmental proliferation, 5 had diffuse proliferation and 5 had membranous changes. 3 biopsies were unclassifiable with end-stage changes and 5 showed an unusual combination of pure membranous changes in association with significant crescent formation. The outcome of the latter group of patients was uniformly poor. We think that this group represents a distinct histological entity with a poor prognosis.