Faculty Bibliography

OBJECTIVE. Neuropsychiatric manifestations are common in patients with systemic lupus erythematosus (SLE), but accurate diagnosis is often difficult. We conducted a prospective study to determine the utility of neurometric quantitative electroencephalography (QEEG) as an indicator of cerebral dysfunction in SLE patients. METHODS. Fifty-two SLE patients were divided into 4 groups based on the results of neuropsychiatric evaluations. These included patients with objective evidence of neuropsychiatric SLE (NPSLE), patients with neuropsychiatric symptoms, patients with no evidence of NPSLE, and patients with a prior history of NPSLE. All QEEG findings were compared with data in an age-regressed normative database and with findings in an independent sample of normal subjects. RESULTS. QEEG sensitivity was 87%, and specificity was 75%. QEEG results were abnormal in 74% of the SLE patients with neuropsychiatric symptoms and in 28% of the patients with no evidence of active NPSLE. QEEG profiles varied as a function of the severity and type of neuropsychiatric manifestation present. Within this patient population, QEEG was more sensitive than magnetic resonance imaging, computed tomography scanning, or conventional EEG. CONCLUSION. Neurometric QEEG may be a sensitive indicator of cerebral dysfunction in patients with NPSLE and can differentiate patients with diverse neuropsychiatric manifestations. When combined with a careful clinical history and evaluation, QEEG provides information that may be useful for the early detection of NPSLE and for serial evaluation of disease activity and treatment efficacy

To evaluate a flare of systemic lupus erythematosus (SLE) during pregnancy and to differentiate it from diseases of pregnancy, serological parameters are often utilized. However, there are conflicting reports regarding the merit of conventional measurements of complement and activation products. While in normal pregnancy the levels of serum C3, C4, and CH50 gradually rise, a decline in these levels occurs during the course of pregnancy in selected SLE patients. There is controversy regarding whether such falls represent decreases in the overall synthesis of complement or activation, the former theory being supported by a report of normal levels of the C1s-C1 inhibitor complex. During normal pregnancies, increases of complement split products, such as plasma C3a, may occur, and these correlate positively with elevations of C3. In pregnancies complicated by lupus, increases of C3a are often accompanied by a decline in total C3 and CH50. In a minority of non-SLE patients, preeclampsia has been associated with elevations of a variety of complement split products. Ba, C3a, C4d, SC5b-9, indicating activation of both the classical and alternative pathways. The CH50 levels tend to remain normal in these patients. In contrast, elevations of complement split products frequently accompany disease flares in patients with SLE. A high ratio of CH50/Ba may differentiate patients with preeclampsia from those with active SLE. A decline in conventional measures of C3, C4, or CH50 which is accompanied by elevations of complement split products appears to differentiate a lupus flare from non-SLE diseases of pregnancy

OBJECTIVE. To determine whether increased levels of the complement split products generated in the activation of the alternative or classical pathway accompany more severe disease activity in patients with systemic lupus erythematosus (SLE) and whether these measurements are useful in predicting flares of disease. METHODS. Levels of Ba, Bb, SC5b-9, and C4d were measured in 380 plasma samples obtained from 86 SLE patients who were prospectively followed up for 15 months. RESULTS. In the 20 patients who had inactive disease at the initiation of the study, the mean values of all of the complement split products at entry were within the normal range. In the 47 patients with stable or moderate disease activity, levels of Ba were significantly increased, while the mean values for Bb, SC5b-9, and C4d did not differ significantly from those in patients with inactive disease. The mean entry value of each analyte was highest in the group of 19 patients who had the most severe disease activity at initial evaluation. Traditional measurements of complement, i.e., C3, C4, and CH50, followed similar trends, but did not discriminate between the 3 groups of patients as well as did measurements of the split products. Analysis of the disease course in the patients with inactive or stable/moderate disease revealed that an elevated level of C4d had the most sensitivity with regard to subsequent flare, while an elevated Bb level had the highest specificity and the greatest predictive value. CONCLUSION. These data suggest that elevated levels of complement split products, particularly products of alternative and terminal pathway activation, more accurately reflect disease activity than do conventional measurements of complement in SLE and may be useful in the prediction of impending disease flares

Nitric oxide provokes vasodilation and inhibits platelet aggregation. We examined the effect of nitric oxide on superoxide anion production by three sources: activated intact neutrophils, xanthine oxidase/hypoxanthine, and the NADPH oxidase. Nitric oxide significantly inhibited the generation of superoxide anion by neutrophils exposed to either FMLP (10(-7)M) or PMA (150 ng/ml) (IC50 = 30 microM). To determine whether the effect of nitric oxide on the respiratory burst was due to simple scavenging of O2+, kinetic studies that compared effects on neutrophils and the cell-free xanthine oxidase system were performed. Nitric oxide inhibited O2+ produced by xanthine oxidase only when added simultaneously with substrate, consistent with the short half-life of NO in oxygenated solution. In contrast, the addition of nitric oxide to neutrophils 20 min before FMLP resulted in the inhibition of O2+ production, which suggests formation of a stable intermediate. The effect of nitric oxide on the cell-free NADPH oxidase superoxide-generating system was also examined: The addition of NO before arachidonate activation (t = -6 min) significantly inhibited superoxide anion production. Nitric oxide did not inhibit O2+ when added at NADPH initiation (t = 0). Treatment of the membrane but not cytosolic component of the oxidase was sufficient to inhibit O2+ generation. The data suggest that nitric oxide inhibits neutrophil O2+ production via direct effects on membrane components of the NADPH oxidase. This action must occur before the assembly of the activated complex

S-nitrosoglutathione (SNO-GSH), a stable derivative of nitric oxide, is an endothelium-derived relaxation factor, which provokes vasodilation, inhibits platelet aggregation, and inhibits neutrophil (PMN) superoxide anion (O2+) generation. We have established a novel method for synthesis of S-nitrosoglutathione using a column containing S-nitrosothiol covalently attached to agarose. S-nitrosoglutathione was a product as assessed after separation using C-18 reverse-phase HPLC and absorption spectroscopy. We examined the stability of SNO-GSH in the presence or absence of PMN. The half-life (mercuric acid diazotization) of SNO-GSH in Hepes was greater than 60 min. The addition of resting PMN did not affect the T1/2 of SNO-GSH. PMN exposed to N-fMet-Leu-Phe (FMLP, 10(-7) M) reduced measurable SNO-GSH (15 microM) at 5 min (48 +/- 5.0% control, P less than 0.05). Incubation (5 min, 37 degrees C) of PMN with 10 microM tenidap (an anti-inflammatory drug which inhibits PMN activation) before addition of FMLP blocked the PMN-dependent degradation of SNO-GSH (42 +/- 3 vs 78 +/- 1.3% control, P = 0.01). We confirmed the recovery of SNO-GSH through measurements by bioassay (platelet aggregation) and HPLC analysis. The degradation of S-nitrosothiols by activated neutrophils may reverse the inhibitory effect of S-nitrosothiols on PMN functions and contribute to tissue injury at sites of inflammation