[Glucocorticoid monotherapy for Cogan syndrome?]

A 27-year-old woman suddenly developed persistent rotatory dizziness with unsteadiness on standing and walking, associated with symptoms relating to the autonomic nervous system, all signs and symptoms disappearing without treatment in 3 days. Ten days before this episode she had noticed progressive bilateral impairment of hearing accompanied by tinnitus. Caloric and audiometric tests confirmed bilateral impairment of the audiovestibular organ. A week later she also developed bilateral iritis and papillitis. The constellation of ocular and audiovestibular signs suggested Cogan's syndrome. Under high-dosage glucocorticoid treatment (initially 1,000 mg/d prednisolone intravenously for 3 days, then 100 mg/d orally in decreasing doses down to 10 mg daily) the ocular signs improved, but the bilateral hearing impairment persisted. A recurrence occurred after 5 months, while on a prednisolone dosage of 10 mg daily, together for the first time with arthralgias, suggesting systemic involvement. Although the symptoms quickly subsided when dosage was increased to 100 mg daily, repeated attempts at dose reduction brought about renewed exacerbation at 70 mg daily. As the necessary high steroid dosage led to severe side effects, an immunosuppressive drug was added (100 mg cyclophosphamide and 20 mg prednisolone, both daily; later 5 mg methotrexate weekly and 4 mg prednisolone every other day). The symptoms had not recurred when re-examined 7 months later.

Renal complications of infected ventriculoatrial shunts

Contamination of a ventriculoatrial shunt (VAS) with skin organisms that are usually nonpathogenic may be followed by an immunologically mediated renal injury. The bacteria characteristically involved are coagulase-negative Staphylococci (e.g., Staphylococcus epidermidis), which strongly adhere to the plastic surface of the VAS. These bacteria are protected from the body's natural defense mechanisms and respond only poorly to antibiotics. As a result, their growth persists and produces a continuous antigenic stimulation. Circulating immune complexes (CIC) are an appropriate tool to screen for chronically infected VASs. We followed CIC in 138 VAS patients. An infected VAS was seen in 20 of the 24 patients with highly elevated CIC and in 1 of the 19 patients with moderately elevated CIC, but none of the 95 patients with normal CIC had evidence of shunt infection. Of the 21 patients with shunt infections, 8 had renal involvement (4 requiring dialysis, and 4 with proteinuria, hematuria, and/or elevated creatinine). Results from kidney biopsy specimens available from 4 patients confirmed glomerulonephritis. Of the 4 patients requiring dialysis at diagnosis, renal function recovered sufficiently to stop dialysis after successful VAS exchange in all but 1. In the other 4 patients, renal symptoms (proteinuria, creatinine) also improved after VAS revision. Chronic infection with S. epidermidis or other bacteria is a continuing problem in patients with VASs and can lead to an immune-mediated renal injury. However, the prognosis for reversal of the renal injury is relatively good if the VAS infection is treated promptly.

Reverse flux filtration: a new mode of therapy improving the efficacy of heparin-induced extracorporeal LDL precipitation in hyperlipidemic hemodialysis patients

In the steady state after a run-in phase of 3 months, the acute effects of 3 modifications of weekly heparin-induced extracorporeal LDL precipitation (HELP) were studied in 5 ESRD and 2 non-uremic hypercholesterolemic coronary patients. In ESRD patients (n = 29 sessions), HELP reduced LDL-cholesterol (LDL-C) (56 +/- 7%) and fibrinogen (FIB) (54 +/- 10%) by a similar percentage as compared to non-uremic controls (60 +/- 4% and 61 +/- 3%, resp.; n = 5). In order to eliminate the need for extra HELP sessions in addition to the normal dialysis regimen, newly developed hardware was then used to perform combined synchronous HELP/HD (n = 12). However, premature precipitate filter plugging probably due to hyperfibrinogenemia in ESRD patients, accentuated by ultrafiltration (UF), decreased the corresponding reductions to 26 +/- 9% (LDL-C) and 34 +/- 11% (FIB). Therefore, the procedure was modified by reversing the filtrate flux through the precipitate filter membrane after 900 ml of treated plasma ("reverse flux filtration", RFF; n = 11). Thus, in RFF-HELP/HD the LDL/FIB/heparin coprecipitate was deposited on both filter membrane sides which caused a significant enhancement of the filter capacity and improved reductions to 46 +/- 14% for LDL-C and 51 +/- 15% for FIB. Elution of the precipitate from the precipitate filter after the sessions showed that RFF-HELP/HD had trapped 1733 +/- 238 mg LDL-C and 8108 +/- 1876 mg FIB in ESRD patients, while HELP eliminated 1890 +/- 333 mg LDL-C and only 3663 +/- 369 mg FIB in non-uremics. Filter precipitate recoveries (relative to the mass removed from the patient plasma pool) amounted to 97 +/- 18% for LDL-C and 158 +/- 67% for FIB in the ESRD group treated by RFF-HELP/HD vs. 70 and 76% in the non-uremic HELP group. Probably, passive transport of lipoproteins and FIB from the interstitium into the vascular space caused repletion of this compartment during HELP/HD where an UF induced solvent drag is effective. In summary, the new RFF-HELP/HD procedure effectively reduced LDL-C and FIB in ESRD patients who could not be adequately treated by the conventional HELP/HD system.

[Interstitial lupus nephritis]

A 17-year old-male presented with a 6-week history of weight loss, lassitude and calf pains. On examination he was very pale. Laboratory tests showed a very high erythrocyte sedimentation rate (155 mm in the first hour), anaemia (haemoglobin 10.1 g/dl), and a raised serum creatinine of 1.54 mg/dl. Microhaematuria (5-10 erythrocytes/microliter) and pronounced pyuria (500 leucocytes/microliter) were present, but the urine was sterile and there was no increase in albumin excretion. The serum IgG was raised to 75.7 g/l, suggesting an autoimmune disorder. Anti-nuclear antibodies (titre 1 : 1920) and anti-double-stranded DNA antibodies (31 U/ml) were present, while the serum complement C4 was decreased to 0.11 g/l. Renal histology showed an interstitial nephritis without glomerular involvement, while the bone marrow showed vasculitis accompanied by a prominent plasma-cell infiltrate. A diagnosis of interstitial nephritis associated with systemic lupus erythematosus was made, with asymptomatic cardiac and hepatic involvement. Renal function recovered rapidly with prednisolone therapy (initial dose 2 mg/kg.d). While glomerulonephritis is the most common lupus-associated renal disorder, isolated interstitial nephritis may occur in some cases, often with an absence of proteinuria.

Adsorption profile of commercially available adsorbents: an in vitro evaluation

Adsorbents from four commercially available devices, Protein A-Sepharose (Immunosorba Protein A-62,5; Excorim KB, Lund Sweden), Tryptophan-PVA (Immusorba TR-350; Asahi Medical Co., Tokyo, Japan), Phenylalanine-PVA (Immusorba PH-350; Asahi Medical Co., Tokyo, Japan), and Dextran sulfate (Liposorber LA-15; Kanegafuchi Chemical Co. Ltd, Osaka, Japan) were tested under optimal in vitro conditions to determine their adsorption capability for several plasma constituents which are usually the target of plasma therapy. The parameters of interest were: double stranded DNA-antibodies (anti-dsDNA), antiglomerular basement membrane antibodies (anti-GBM), anti-acetylcholin receptor antibodies (AChRAb), circulating immune complexes (CIC), rheumatoid factor (RF), IgA, IgG, IgM, IgE, C3c, C4, LDL-cholesterol, total cholesterol, erythropoietin (EPO) and beta 2-microglobulin (beta 2M). The IgG auto antibodies, CIC and RF can be removed by Protein A-Sepharose, Try-PVA and Phe-PVA. IgG is best adsorbed by Protein A-Sepharose, while IgE can be removed efficiently by Try-PVA. Dextran sulfate is without doubt the best adsorbent for LDL-cholesterol. All four adsorbents bind also complement components C3c and C4. No significant adsorption was found for EPO and beta 2M. The four devices exhibit a quite different adsorption profile which can be used as a guide for the optimal selection of an adsorption column in clinical apheresis.

[MRT in dialysis-associated destructive spondylarthropathy of the atlantoaxial region]

Destructive bone and joint diseases in patients on longterm haemodialysis increase in frequency and are often caused by beta 2-microglobulin-related amyloid deposits. Due to the excellent visualisation of amyloid, MRI with T1-weighted and out-of-phase gradient recalled long TR images is the diagnostic modality of choice. 5 patients, 13 to 21 years on haemodialysis, were investigated. In four patients we found involvement of the atlantoaxial region, one patient was asymptomatic, the other three had severe neurological deficiencies.

Recombinant human erythropoietin in nephrology

rEPO therapy provides a unique opportunity to correct anemia in end-stage renal failure patients. Complete correction of the anemia, although possible, has some obvious disadvantages over a partial correction with a target hemoglobin of 10-13 g/dl or a hematocrit of 30-35%, respectively. Unresponsiveness to rEPO seems to be rare; in most cases the predicted hemoglobin increase could be seen as soon as an underlying iron deficiency was treated adequately. Blood loss and aluminum toxicity are the next most frequent reasons for an inadequate response to rEPO. Hypertension (and its complications) as well as fistula clotting are the most important side-effects which require close attention when patients at risk for these complications are treated with rEPO.

Long-term remission of immune neutropenia after treatment with high-dose intravenous 7S-immunoglobulin

In a 61-year-old woman recurrent bacterial infections were caused by immune neutropenia which was resistant to high-dose cortisone and plasmapheresis. However, high-dose intravenous 7S-immunoglobulin therapy (30 g for 6 days) induced a long-term remission for 35 months. This treatment modality is safe and should be used as a first-line agent.

Ex vivo biocompatibility evaluation of a new modified cellulose membrane

To evaluate membrane biocompatibility, an open loop ex vivo model was designed simulating the hemodialysis procedure. Blood was withdrawn continuously from healthy nonuremic donors, heparinized, and pumped through a module containing the membrane to be studied. C3a generation in the module was determined at various time points comparing the cuprammonium cellulose (CC) membrane and four types of modified cellulose (MC) membrane, each with a different degree of hydroxyl (OH-) group substitution. In other studies, C3a generation in the ex vivo mode was compared with that during in vivo dialysis. In the ex vivo model, C3a generation with MC membranes was reduced by 70% compared with CC. However, within the MC group, the degree of C3a generation did not correlate with the degree of OH-group substitution. In vivo studies confirmed the reduced degree of C3a generation with the MC membrane compared with CC. Additionally, validation studies using the CC membrane showed excellent agreement between C3a generation during ex vivo perfusion and in vivo dialysis. The results suggest that a group of new MC membranes causes substantially less complement activation than the CC membrane but that the degree of complement activation with various subtypes of MC membranes is not related to the degree of OH-group substitution.

Ex vivo and in vivo protein A perfusion: background, basic investigations, and first clinical experiences

During the past several years clinical protein A perfusion has attracted much attention because it allows to selectively remove IgG subclasses 1, 2, 4 and probably IgG-containing immune complexes, and has a tumoricidal effect in experimental animals and in some cancer patients. Due to several drawbacks, this therapy is not yet generally accepted. Our first experience with laboratory and clinical protein A perfusions confirms several limitations of this new apheresis therapy. Plasma IgG extraction in the ex vivo system under investigation and during clinical application of protein A perfusion reached a 10:1 ratio of grams IgG removed per gram solid-phase protein A only in 2 of 5 runs. Nevertheless, the absolute amount of IgG removed was very low in all runs due to the restricted protein A load (maximum 200 mg) per column. Removal capacity can be increased by a two-column switch-over system with subsequent perfusion and elution. Furthermore, the side effects observed in both in vivo treatments exceeded by far those of other extracorporeal therapies and had not been observed in more than 1,200 unselective plasma exchanges or in 50 cascade filtrations in our center. C3a generation in protein A perfusion is, however, comparable to cascade filtration, but exceeds that of unselective plasma exchange and is lower than in hemodialysis. Consequently, side effects in protein A perfusion cannot be correlated with the total amount of anaphylatoxin generated but may be due to a leakage of protein A or contaminants. Clinical application of protein A perfusion needs a more detailed elaboration in respect to biocompatibility, removal capacity, and the significance of the induced biological effects.

[Are C1q binding immune complexes appropriate as markers for infected ventriculo-atrial shunts?]

Routine C1q-fluid phase radioimmunoassay identified high levels of C1q-binding immune complexes in 3 patients with infected ventriculoatrial shunts (VAS). Accordingly, C1q-binding activity was prospectively studied in additional 36. VAS patients to learn whether the observed immune complex activity was secondary to bacterially contaminated shunts or was a normal sequela of continuous intravenous infusion of cerebrospinal fluid into the vascular space. Pathological levels of C1q-binding activity were detected in only 3 out of 32 patients without evidence of shunt infection. However, extremely high C1q-binding activities were measured in 4 more patients with proven shunt infections. Thus, elevated levels of C1q-binding immune complexes correlate with infected VAS. As shunt infection is otherwise difficult to detect, serum C1q-binding activity may prove to be a valuable diagnostic tool for this condition.

Current status of membrane plasma separation and plasma filtration techniques

Blood and plasma processing by membranes was introduced into clinical medicine in 1979. In the meantime, membrane plasma separation (plasmapheresis) has become very satisfactory and is now a routine therapeutic procedure in many apheresis centers. Plasma fractionation by membranes (plasma filtration or cascade filtration) for unselective removal of high molecular weight pathogens from the separated plasma is technically possible but its routine clinical application is still limited to a few diseases with at least IgM-sized target proteins. The separation of IgG from albumin needed to treat many autoimmune diseases requires further development of both the membranes and the filtration technology.

Analytical comparison of single-pass and dead-end operation in cascade filtration plasmapheresis

Derived mathematical models are employed to compare cascade filtration plasmapheresis in the dead-end and single-pass formats. The high filtration fraction and low sieving coefficients associated with single-pass cascade filtration are shown to require treatment of the retentate concentration profile in an integrated rather than a length-averaged fashion. The models are best applied to specific simulations, but in general predict that (a) for a given membrane, the dead-end format will yield a higher albumin recovery but a lower macroglobulin rejection than single pass; (b) the single-pass format is more suited to loose membranes and the dead-end to tight membranes; and (c) in the single-pass but not the dead-end format, solute recovery is conveniently independent of the quantity filtered. Agreement between predicted and measured performance is good, although a larger data base would be required for complete validation of the models.

Plasma exchange and concomitant therapy in TTP

Since plasma exchange was introduced in the management of thrombotic thrombocytopenic purpura (TTP) in 1977, patient survival rate has increased from 10 to 80%. However, approximately 50 subsequent case reports in the literature provide no consensus as to the optimal therapy. We review here 4 episodes of TTP in 3 patients. In all cases, treatment was started with intensive FFP plasma exchange combined with administration of antiplatelet agents and corticosteroids. Remission was achieved in 3 out of 4 episodes although all required individualization of the medication regimen. In the remaining patient, cytotoxic therapy (vincristine) and ultimately splenectomy were required to achieve stable remission. The variable clinical response to these therapeutic protocols indicates that TTP may not represent a single homogeneous disease entity but rather may involve various underlying pathologies. We conclude that the most effective present therapy for the management of TTP is daily plasma exchange with fresh frozen plasma infusions combined with antiplatelet agents and steroids. Vincristine and splenectomy should only be employed if this protocol proves ineffective.

A comparison of centrifugal and membrane-based apheresis formats

Membrane and centrifugal apheresis operate on different physical principles but are both capable of efficiently fractionating plasma proteins from whole blood. For therapeutic purposes, both formats yield about the same protein clearance per liter of solute exchanged and neither is significantly more rapid than the other. Only continuous centrifugation can be used to pherese cellular elements and only membrane filter can be deployed in 'spontaneous' circuits. Hardware for continuous centrifugation is more expensive and disposables less expensive than for the membrane methods; the 'crossover' occurs at 200 treatments. To date, only the centrifugal method is employed for donor apheresis; this may change in the future as membranes can yield a truly platelet-free product and appear to offer a much more rapid collection cycle.

Membrane plasma exchange: principles and application techniques

Membrane plasmapheresis was introduced in 1978 as a new method for performing therapeutic plasma exchange. Its principal advantages over traditional techniques include speed, ease of performance, and ready adaptability to clinical centers already performing routine extracorporeal therapy. The appearance of a membrane plasmapheresis circuit (vascular access, anticoagulation, connectology) is similar to that of hemodialysis and especially hemofiltration; the operating protocols (treatment time, filtration rates, pressures, pharmacokinetics) are quite different. Particular attention must be paid to avoiding operating conditions that lead to hemolysis. In clinical use membrane plasma separation is as effective as centrifugal plasma exchange in removing plasma proteins. The sieving coefficients for proteins with a molecular weight (MW) ranging from 67,000 (albumin) to 2,400,000 (beta-lipoprotein) daltons are unity. An exchange of one patient plasma volume has been shown to cause a 55% reduction of the serum levels of intravascular proteins. There are no significant differences between membrane and centrifugal plasmapheresis in substitution fluid requirements (human albumin or fresh frozen plasma), indications for treatment and complications. The next major advance in plasmapheresis technology will almost certainly be development of a "closed loop" circuit in which filtered plasma is treated to remove the offending moiety and returned to the patient. This would eliminate both the cost and the possible side effects of replacement fluid. Membrane-based systems are already available for removing cryoglobulins or proteins with MW of at least 900,000 daltons.