Histuria and fibrinuria in cases of systemic lupus erythematosus.

In thirty-nine urine specimens from twenty-seven patients with systemic lupus erythematosus, tissue-like and fibrinogen-like material was looked for by immuno-diffusion techniques, using specific antisera corresponding to both antigenic categories. Half the samples exhibited an abnormal outflow of tissue-like material (histuria). Fibrinuria appeared in only a few instances when cases with microscopic haematuria were discarded. Abnormal histuria had a significant correlation with the following signs of consistent lupoid renal involvement: significant urinary total protein output (>2 mg/min), impairment of renal function and extracapillary epithelial proliferation in the glomeruli seen on biopsy. In systemic lupus erythematosus with evidence of renal involvement, the major origin of abnormal histuria is probably a direct leakage of macromolecules from damaged kidney tissue. Abnormal histuria was also observed in cases of systemic lupus erythematosus during subacute stages of the disease without any signs of renal involvement. In the latter case, histuria is likely to originate from damaged tissues outside the kidney. It is concluded that abnormal histuria during the course of systemic lupus erythematosus may indicate various organic alterations, especially in the kidney, consequent to the primary mechanism of the systemic lupoid disease. On the contrary, fibrinuria may be diverse in origin.