Faculty Bibliography

The heterogenous immunoglobulins known as antiphospholipid antibodies (APLA) or lupus "anticoagulants" (LA) are prevalent in lupus patients and have been implicated in life-threatening thromboembolic events. Unfortunately, observing the presence of these antibodies in an individual does not predict the likelihood of an event nor does it predict when it may occur. A pathogenic role for these antibodies is supported by the observation that high titers and IgG isotype confer an increased risk of thromboembolism. Additionally, numerous reports indicate that isolated patient antibodies interfere with various elements of the coagulation cascade. Nevertheless, attempts to correlate specific antibody characteristics with the future likelihood of a hypercoagulable event in an individual patient have been unsuccessful to date. Given such uncertainty combined with the potential complications of anticoagulant medications, patients are generally not treated until significant morbidity has occurred. Finally, because of the apparent high rate of reoccurrence most patients must remain on anticoagulant therapy indefinitely, regardless of need.

The current study was initiated to estimate the use of oral contraceptives and estrogen replacement therapy in women with systemic lupus erythematosus (SLE). Four hundred and four patients were surveyed from five medical centers. Two hundred and twenty four (55%) had ever used oral contraceptives, however, only 51 (13%) were taking oral contraceptives at the time SLE was diagnosed. Fifty five (14%) used oral contraceptives after their disease was diagnosed. Only seven (13%) reported an exacerbation of disease activity, mostly confined to the musculoskeletal system. In one substudy, there were no significant differences observed between women with or without SLE with regard to the frequency of ever-use of oral contraceptives. In contrast, significantly fewer women with established SLE were taking oral contraceptives at the time of interview compared with healthy women, p < 0.02. In a second substudy, information on past and present usage of estrogen replacement therapy was obtained in women followed at two of the sites included in the main study. Fifty-five (59%) of the 94 postmenopausal patients at these centers had ever taken estrogen therapy, 23 (24%) at the time of diagnosis. Forty-eight women (51%) began or remained on estrogen therapy after the diagnosis of SLE, four (8%) of whom reported exacerbations of disease activity. A significantly higher percentage of Caucasian women had taken or were taking estrogen replacement compared with other ethnic groups. This study suggests that exogenous hormones were generally well tolerated by women with SLE; this preliminary observation is based on patient recall. The low frequency of current oral contraceptive use in lupus patients of reproductive age may reflect, in part, bias of the managing rheumatologists and obstetricians/gynecologists. Given the health needs of and potential benefits for women with SLE, these observations suggest that larger prospective studies are critical and are likely to change prescribing practices for exogenous estrogen

The role of phosphorylation and dephosphorylation events in homotypic neutrophil aggregation mediated by CD11b/CD18 molecules was investigated using okadaic acid, an inhibitor of serine and threonine phosphatases. In the absence of exogenous stimuli the addition of okadaic acid to neutrophils resulted in a dose-dependent increase in phosphorylation of the CD18 beta chain that was further augmented by PMA but unaffected by FMLP. Phosphorylation induced by okadaic acid was reversed by staurosporine and minimally decreased by the less selective PKA/PKC inhibitors, H-7 and H-8. This suggests the existence of constitutive phosphatase and kinase activity emphasizing the dynamic state of phosphorylation and dephosphorylation of the beta 2 integrins. Unlike PMA, okadaic acid did not promote homotypic neutrophil aggregation. Furthermore, both the PMA-induced pathway of irreversible aggregation, blocked by staurosporine, as well as the FMLP-induced pathway of reversible aggregation, augmented by staurosporine, were inhibited by okadaic acid in a dose- and time-dependent manner. These results provide evidence that a phosphatase-dependent step is involved in each of these two distinct pathways that regulate neutrophil aggregation mediated by beta 2 integrin activation

Eight women with prospectively documented premenstrual syndrome (PMS) underwent multiple samplings for estradiol, progesterone, prolactin, cortisol, and plasma 3-methoxy-4-hydroxyphenylglycol (MHPG) during an asymptomatic midcycle (late follicular) and a symptomatic premenstrual (late luteal) phase of the menstrual cycle. Cerebrospinal fluid (CSF) was collected for analysis of MHPG, norepinephrine (NE), 5-hydroxyindoleacetic acid (5-HIAA), dihydroxyphenylacetic acid (DOPAC), gamma-aminobutyric acid (GABA), homovanillic acid (HVA), tyrosine, tryptophan, beta-endorphin, prostaglandins, adrenocorticotropic hormone (ACTH), and arginine vasopressin (AVP). In subsequent months, a dexamethasone suppression test (DST) and a thyrotropin-releasing hormone (TRH) stimulation test were performed during midcycle and premenstrual phases. Significant results included increased CSF concentrations of MHPG in the premenstrual, as compared with the midcycle, phase of the cycle, and increased plasma cortisol concentrations during the midcycle phase. The DST showed a 62% overall rate of nonsuppression, irrespective of menstrual cycle phase. Though there were no abnormalities of thyrotropin-stimulating hormone (TSH) after TRH stimulation, the mean delta maximum prolactin values after TRH stimulation were higher than reported normal values both at midcycle and premenstrually. These pilot data suggest hormonal axes that might be worthy of further systematic investigation in future studies of PMS.

C receptor CR3 (iC3b-receptor, CD11b/CD18) plays an essential role in several phagocytic and adhesive neutrophil functions. Recent evidence suggests that stimulus-induced phosphorylation of the CR3 beta-chain, CD18, may mediate certain neutrophil functions by transiently converting the molecule to an activated state. Staurosporine, a protein kinase C inhibitor that blocks PMA-induced CD18 phosphorylation, was used to study the functional relevance of this event. Neutrophils adhered to glass were assayed for binding and phagocytosis of iC3b-opsonized sheep E (EC3bi) in the presence or absence of PMA and/or staurosporine. Binding of EC3bi was markedly increased, not only by PMA, but also by staurosporine and by a combination of both agents (three- to sevenfold). The enhancement of rosetting by staurosporine was likely caused by increased surface expression of CR3 via exocytosis of specific granular contents. In contrast, staurosporine alone did not stimulate phagocytosis of EC3bi and markedly inhibited PMA-induced phagocytosis. Staurosporine also inhibited phagocytosis of yeast beta glucan particles, a CR3 ligand that, in contrast to EC3bi, is bound and ingested without additional prior treatment with PMA. beta glucan phagocytosis was associated with a low level of CD18 phosphorylation. Staurosporine did not block phagocytosis in general, because this agent had relatively little effect on FcR-mediated phagocytosis. These data demonstrate that phagocytosis mediated by CR3 requires activation of CR3 via a staurosporine-sensitive pathway. Increased binding of EC3bi, a function of increased surface expression of CR3, does not require activation of CR3 by such a pathway, confirming previous evidence for the independence of these two phenomena. A direct role for CD18 phosphorylation in the activation of CR3 for phagocytosis is consistent with these data