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Serum levels of soluble interleukin-2 receptors (IL2R) and of β2-microglobulin (β2M) were studied with the immunoenzymatic technique in 38 patients with primary glomerulonephriti

The serum levels of beta 2-microglobulin (beta 2-m) were determined in 80 intravenous drug addicts (IVDA) with acquired immunodeficiency syndrome (AIDS), in 128 HIV-positive IVDA with persistent generalized lymphadenopathy (PGL) and in 44 HIV-seronegative IVDA. Seventy-two out of 80 (90%) AIDS patients had elevated serum beta 2-m levels and high levels of beta 2-m were also found in 105 of 128 (82%) HIV-infected subjects without AIDS. The mean beta 2-m level was significantly higher in HIV-infected patients with PGL than in HIV-negative IVDA. Nine out of 64 (14%) PGL patients developed AIDS in a period of 24-54 months. In these patients the mean beta 2-m level (5.16 +/- 2.37 mg/l), obtained from sera stored at the first observation, was significantly higher than in the other PGL patients (3.40 +/- 1.03 mg/l); in particular, 5 out of 7 PGL patients with beta 2-m levels greater than 5.0 mg/l showed an advanced disease.

Neutrophil oxidative metabolism, C3d and beta 2 microglobulin levels, were assessed in nine consecutive patients undergoing cardiopulmonary bypass surgery with polypropylene hollow fiber oxygenators for open cardiac operations. Generation of oxygen free radicals by neutrophils was measured as luminol-enhanced chemiluminescence after stimulation with opsonized Zymosan and phorbol myristate acetate. A significant increase in light emission was detected by using both of the chemiluminescence stimulators. Moreover, a remarkable and significant increase in C3d levels was found already at 10 min. Conversely minimal changes in levels of beta 2 microglobulin were detected during cardiopulmonary bypass surgery. These data suggest that the impact of the patient blood with the foreign surface of cardiopulmonary bypass results in activation of phagocyte cells with increased potential in oxygen consumption. These effects could be partially complement-mediated.

We analysed the possible mechanisms responsible for the functional abnormalities reported on phagocyte cell function in IgA nephropathy patients. The oxidative metabolism by the superoxide anion ferricytochrome C reduction test on monocytes and the chemiluminescence response on neutrophils was examined in 32 patients. Moreover the expression of cell membrane structures involved in immune response and phagocytosis (i.e. Fc receptors and HLA class II antigens) was evaluated cytofluorimetrically using specific monoclonal antibodies. Our own results did not show striking differences in oxidative potential and phenotype of patients' phagocyte cells as compared with healthy controls. However a HLA class II-associated structure was found to be quantitatively more expressed in patients' monocytes than in normal controls (P less than 0.005). These findings suggest that the defective phagocyte system function reported in IgA nephropathy patients is not simply due to a loss of cell surface receptors, nor to abnormalities in intracellular metabolic pathways implying oxygen consumption. The increase in expression of some HLA class II structures, often associated with the presence of circulating IgA immune complexes, probably reflects a protracted immunological stimulation.

Reflux nephropathy is an important cause of chronic renal failure in children. After the parenchymal scar, the progression is thought to be mediated by glomerular hypertension in remnant nephrons resulting in modifications in permselectivity to macromolecules. Proteinuria correlates with a progressive course. The glomerular permselectivity to macromolecules in basal conditions and after acute hemodynamic stress was investigated in 28 children whose bilateral vesico-ureteric reflux (VUR) had been previously surgically corrected (meanly 5.6 years before) and with normal creatinine clearance (CrCl). Bilateral renal scarring (0 to 8 scale for both kidneys) was 4.3 +/- 1.6. Albuminuria (UAE) was evaluated in basal conditions and under acute hyperfiltration induced by amino acid (Aa) infusion. After isotonic saline at 310 ml/hour/1.73 m2, 6 mg/kg/min of Aa were infused for 2 hrs. UAE was significantly higher than controls in basal conditions (p < 0.01), and further increased after Aa infusion (p < 0.02). Microalbuminuria was detectable in 53.5% of the children in basal conditions and in 64.3% after Aa. Also urinary beta 2 microglobulin significantly increased at the end of the test (p < 0.001). CrCl significantly increased at the first hour (p < 0.05). Children with severe renal parenchymal scarring had greater UAE (p < 0.01) and beta 2M (p < 0.02) values after provocative test than those with mild renal damage. In 8 children GFR and ERPF were measured by means of inulin and p-hippurate clearance respectively. The variations in UAE during Aa infusion were significantly correlated with GFR dynamics (p < 0.05) while they were not influenced by ERPF modifications.(ABSTRACT TRUNCATED AT 250 WORDS)