Single-needle thrombo-cytapheresis with the Fresenius AS 104

BACKGROUND

The Fresenius AS 104 cell separator has recently met some popularity in European apheresis units for the quality of the platelets obtained with the totally automated double-needle procedure.

MATERIALS AND METHODS

Taking advantage of the machine's flexibility we have developed a new automated procedure for single-needle thrombocytapheresis (SNP). So far 61 SNP were carried out. From donors having a platelet precount of 2.74 x 10(5) an average of 3.8 x 10(11) cells were collected by processing 2.5 liters of blood in a run time of 83 min.

RESULTS AND CONCLUSIONS

The leukocyte and erythrocyte contaminations were 2.7 x 10(7) and 3.5 x 10(7), respectively. Only 2 products did contain less than 3.5 x 10(11) platelets, and 7 procedures were complicated by minor signs of hypocalcemia. With minor modifications this SNP is presently offered on a routine basis to our platelet donors.

Excel: a new cell separator in its very first clinical application

BACKGROUND

The evolution of technology has been one of the most interesting features that has accompanied thrombocytapheresis throughout the years. In this presentation we report on the preliminary results obtained with Excel, a third-generation cell separator that is presently in its early experimental phase.

MATERIAL AND METHODS

So far only 15 thrombocytapheresis procedures, 2 of which of the single-needle type, were carried out on 15 healthy donors processing 4 liters of blood (2.8 liters in single needle).

RESULTS AND CONCLUSIONS

The results were satisfactory since the average platelet yield was 4.7 x 10(11). The leukocyte contamination was 0.8 x 10(6) and the RBC contamination 0.4 x 10(7). The platelet efficiency per minute was 6.5 x 10(9), and the run time average 72 min. As to the quality of the product the very first results of platelet aggregation, relative to pre-apheresis, were 78% in response to ADP 6 microM; 106 and 102% in response to collagen 4.5 micrograms/ml and ristocetin 1.5 mg/ml, respectively. Essentially no platelet aggregates were found in the platelet products (Wu-Hoak ratio: 0.91).

[Report on surgical strategy in reoperation of esophageal achalasia]

Surgical therapy for achalasia of the esophagus gives good results in only 80-90% of cases. Several reasons could be responsible for this 10-20% failure; the most frequent causes are inadequate cardiomyotomy and reflux esophagitis. We report our experience and our procedure in the management of recurrent achalasia. The most important controversies are also discussed.

Plateletpheresis with the new Fresenius AS 104 blood cell separator

Among the many blood cell separators introduced into the international market in these last few years, the Fresenius AS 104 represents an advanced and safe thrombocytapheresis machine whose development took advantage of extensive worldwide experience with blood cell separation. Nonetheless the AS 104 has generated most interest in West Germany and most, if not all, the studies published on its platelet collection efficiency have been carried out in that country. It is normally reported that from 2.7 to 3.5 x 10(11) platelets can be collected in approximately 80 minutes. Since these results could not be duplicated routinely in our hemapheresis unit, we set up a study by modifying the standard procedure. It was possible to reduce the procedure time and to collect platelet concentrates containing more than 4 x 10(11) cells on a routine basis by using the following procedure: ACD-A/blood ratio 1:10; Interface position 6:2; blood flow rate always exceeding 65 mL/min; rpm 1750; cell collection from 4 to 7 mL/min; volume of blood processed 3.6 L followed by the rinsing of the system with 200 ml of saline; extraction of the content of the secondary separation chamber by the action of the plasma pump working at 20 mL/min for 2 min. With this procedure the platelet yield in 34 collections exceeded 3.1 x 10(11) and averaged 4.06 x 10(11). The procedure time was reduced to 56.5 minutes with a mean blood flow rate of 62.3 mL/min. The leukocyte and erythrocyte contamination of the products were in the range of 1 x 10(7) and 1 x 10(8) respectively.(ABSTRACT TRUNCATED AT 250 WORDS)

Cold agglutinin hemolytic anemia in a patient with adult-onset Still's disease

We report on a patient with adult Still's disease who developed, at the onset of her illness, an autoimmune hemolytic anemia (AHA) due to cold agglutinin (CA). Hemolysis spontaneously subsided and CA disappeared before starting therapy with aspirin and prednisone. The occurrence of AHA in patients affected with collagen diseases is currently explained by a loss of tolerance, leading to the emergence of multiple autoreactive clones. In our case the self-limiting course of AHA leads us to propose another interpretation, i.e. that the cold reactive autoantibody might have been related to a transient infection able to play a pathogenetic role in the systemic disease, as suggested by several authors.

Efficacy of discontinuous flow centrifugation compared with cascade filtration in Waldenstrom's macroglobulinemia: a pilot study

In the treatment of Waldenstrom's macroglobulinemia (WM) and lipoprotein or immune complex mediated diseases, centrifugal and membrane plasma separation systems have been successfully employed over the past years. More recently, semiselective double filtration systems have been used in isolated cases. While it is hoped that cascade filtration (CF) will soon become a routine technique, a note of caution came from some investigators because of the lack of any evidence that CF does really deplete patients' plasma of known pathogenic macromolecules. The aim of this study was to test the efficacy of CF in the removal of IgM paraproteins in comparison with discontinuous flow centrifugation (DFC). Eight patients were treated by DFC and seven by CF; there were no significant differences between the two groups in terms of sex, age, clinical severity and IgM plasma concentration. After DFC or CF sessions, IgM concentration diminished by 50% and plasma viscosity by 60%, producing a comparable mean reduction in patients' clinical severity. Our in vivo results thus preliminarily answer the question whether CF is capable of removing known pathogenic macromolecules from patients' plasma, and the technique appears to warrant further investigations.

Biochemical and clinical evaluation of a new cellulose diacetate secondary filter for cascade filtration

We have performed 24 cascade filtration treatments in 8 patients with hyperviscosity syndrome (2 cases), essential mixed cryoglobulinemia, post-hepatitic cryoglobulinemia, Sjogrens disease, rheumatoid vasculitis, Miller-Fisher syndrome and chronic dysimmune polyneuropathy. New cellulose diacetate filters were employed, giving a satisfactory performance. At 1.5 L plasma treatment, the rejection rate for macromolecular plasma components was close to 90%, whereas albumin recovery was close to 70%. Treatments were clinically effective, confirming that cascade filtration is an alternative to conventional plasma exchange in patients with IgM or immune complex mediated diseases.

Plasmapheresis combined with lymphocytapheresis and cytotoxic drugs as a therapeutic modality in neuroimmunological diseases

Rebound after plasmapheresis is thought to be due to enhanced antibody and/or immune complex production. To prevent rebound a combination of steroids and immunosuppressive drugs has been used: lymphocytapheresis was employed in most patients, for not more than 10 sessions. 50 patients with myasthenia gravis, inflammatory myopathy, chronic dysimmune polyneuropathy and immune complex polyneuropathy have been treated and long-lasting benefits obtained in 35 patients. Rebound effects were observed only when cytotoxic drugs were not given or discontinued too soon. 8 patients who had been treated by plasmapheresis combined with steroids alone, after some recurrences of their disease, were switched to cytotoxic drugs, steroids and lymphocytapheresis combined with plasma exchange: in this group 7 patients eventually gained long lasting remissions. Our clinical experience strongly supports the hypothesis of a synergy between plasmapheresis and immuno-suppressive measures.

Cascade filtration: clinical application in 26 patients with immune complex and IgM mediated diseases

A new technique which allows lymphocytapheresis to be combined with cascade filtration (CF) is described in this paper. This therapeutical approach was applied for the treatment of patients affected by necrotizing vasculitis (1), inflammatory myopathies (5), Cryoglobulinemia (5), immune complex polyneuropathies (7), rheumatoid arthritis (3) and psoriasis (3 patients). Two cases of Waldenstrom's macroglobulinemia were also treated after the onset of the hyperviscosity syndrome. 78 procedures have been performed without any untoward effect. From a clinical point of view all patients had some improvement following treatment, thereby confirming not only the clinical safety of this therapeutical approach but also its effectiveness at least in the management of diseases which usually respond to plasma exchange treatment. Laboratory investigations showed that with CF it is possible to selectively remove IgM, immune complexes, fibrinogen, lipoproteins and high molecular weight plasma components, sparing most albumin and IgG globulins (85 and 71%, respectively).

A method for the study of cryoglobulin solubilization curves at 37 degrees C. Preliminary studies and application to plasma exchange in cryoglobulinemic syndromes

A simple method for the study of kinetic solubility curves of cryoglobulins is presented. In its first application to the study of 21 patients with cryoglobulinemia, it was possible to ascertain that clinical condition roughly correlates with decreased solubility whereas no correlation is found with per cent cryocrit. In the group of patients we studied, 6 underwent plasma exchange treatment when glomerulonephritis, acute renal insufficiency, cerebritis and polyneuropathy appeared: in these patients, following 2 to 5 apheretic sessions, solubility increased showing a sort of correlation with clinical benefits determined by treatment. The preliminarity of this study is underlined.

A simple and rapid test for the quantification of osmotic fragility of red blood cells

We have developed a simple and rapid nephelometric test for the quantification of the osmotic fragility of red blood cells. 10 microliters of whole blood are mixed with hypotonic NaCl solutions under mechanical stirring while the hemolysis curve is continuously recorded for 1 min. In our preliminary studies, this test was reproducible, time-saving, easy to set up and to standardize. No false-positive or false-negative results have been recorded so far. Moreover, it seems that this test can differentiate heterozygous beta-thalassemic patients from patients with sideropenic anemia, which was hardly possible with previously proposed assays.

An evaluation of N-ethyl-maleimide-induced lipid peroxidation in platelet concentrates stored at 4 or 22 degrees C

A method for the quality control of platelet viability, based on N-ethyl-maleimide (NEM)-induced lipid peroxidation, is reported. Duplicate platelet concentrates from individual donors were stored at 22 and 4 degrees C, respectively. At time 0 and at 24-hour intervals, pH, O2 and CO2 tensions, ADP-induced aggregation, glass adhesivity, hypotonic shock response (HSR) and NEM-induced lipid peroxidation were measured. A highly significant correlation between NEM-induced lipid peroxidation and HSR was established, which suggests that the former method can be used for the in vitro prediction of posttransfusion survival of preserved platelets.