Chronic idiopathic thrombocytopenic purpura

Treatment of idiopathic thrombocytopenic purpura

ITP is a common disease that is sorely in need of better management. Treatment strategy requires consideration of both long-term benefits and long-term hazards of each available therapeutic option. This discussion reviews conventional therapy as well as newer approaches to refractory ITP, including immunosuppressants, vinca alkaloids, colchicine, androgens, tamoxifen, and plasmapheresis.

Plasma exchange in autoimmune thrombocytopenic purpura

We present data on 5 cases with autoimmune thrombocytopenic purpura treated with plasma exchange in whom conventional drug therapy had been ineffective. In 3, preparation for splenectomy allowed the operation to be performed without bleeding problems. 1 patient who was unfit for splenectomy underwent successful coronary artery vein grafting following preparation with plasma exchange. 2 patients were maintained for variable periods with intermittent exchanges, 1 prior to splenectomy and 1 post-splenectomy. In summary we had no prolonged response to plasma exchange but found it a useful technique as preparation for or adjunctive to more conventional therapy. It was also helpful in patients unresponsive to other forms of therapy who required a brief increase in platelet count to cover surgery or spontaneous haemorrhage.

Immune thrombocytopenic purpura. Use of a 125I-labeled antihuman IgG monoclonal antibody to quantify platelet-bound IgG

We used a radiolabeled monoclonal antibody to the Fc portion of human IgG to measure platelet-bound IgG in 54 thrombocytopenic patients and in 48 normal controls. The control group had a mean (+/- 1 S.D.) of 169 +/- 79 IgG molecules bound per platelet--10 to 100 times lower than values generally reported with other assay techniques. Sixteen of 17 patients with untreated thrombocytopenic purpura considered to be of immune origin had values ranging from 790 to 13,095--levels well above those found in normal subjects and in patients with "nonimmune" thrombocytopenia (246 +/- 156). In a second group, consisting of 11 patients with "immune" thrombocytopenic purpura who did not respond to conventional therapy (corticosteroids or splenectomy), the values were quite divergent: two patients had levels in the normal range, three had levels in the range of subjects with nonimmune thrombocytopenia, and six had much higher levels. Measurement of platelet-bound IgG with this monoclonal-antibody technique can help differentiate between immune and nonimmune thrombocytopenias. Low platelet counts in patients who have immune thrombocytopenia according to clinical criteria but are resistant to therapy may be related to factors other than IgG antibody.

Clinical effect of intravenous immunoglobulin on chronic idiopathic thrombocytopenic purpura

High dose immunoglobulin infusions showed a marked effect on platelet counts in eight out of nine chronic ITP patients and in one SLE patient. In the comparison of different IgG-preparations, the pepsin treated IgG F (ab')2 showed no platelet elevation while the sulfonated did. The elevated platelet count could not be maintained after discontinuation of IgG infusions, but in six out of ten patients the platelet level remained above the pretreatment values. This new treatment seems to be safe and effective in adulthood ITP.

Platelet-associated IgM levels in thrombocytopenia

Platelet-associated IgG (PAIgG) and IgM (PAIgM) levels were quantitated in patients with thrombocytopenias of various etiologies. 32 of 34 patients with immune thrombocytopenia had elevated PAIgG, 8 of the 34 patients had elevated PAIgM levels. Only 1 patient suffering from immune thrombocytopenia had elevated PAIgM with normal PAIgG levels. Elevated PAIgM was most often associated with elevated PAIgG except for the following: 2 patients with lymphoproliferative disorders, 1 patient with heparin-induced thrombocytopenia, 1 patient with pernicious anemia, and 2 patients with Waldenström's macroglobulinemia. PAIgM determinations may prove to be a useful adjunct for evaluating patients with thrombocytopenia, particularly those in whom the PAIgG is not elevated.

Platelet-associated complement C3 in thrombocytopenic states

Platelet-associated complement components C3, C3d and C4 (PAC3, PAC3d, PAC4) were quantitated by a modification of the platelet radioactive anti-IgG test using highly purified C3 antibodies in 74 patients with immune thrombocytopenia (ITP), 26 patients with presumed nonimmune thrombocytopenia (NTP), and 114 normal individuals. Elevated PAC3 levels were found in 26 out of 74 patients with ITP (35%) and in 10 out of 26 patients with NTP. Although the percentage of elevated PAC3 values was higher in thrombocytopenic patients than in nonthrombocytopenic patients, no statistically significant correlation existed between platelet counts and PAC3 levels, neither for ITP nor for NTP. However, such a relationship was demonstrable between PAC3 and platelet-associated IgG, both for ITP (P less than 0.05) as well as NTP patients (P less than 0.001). We conclude that elevated PAC3 values are not restricted to immune thrombocytopenias. Quantitative differences of PAC3 between ITP and NTP patients suggest that part of the PAC3 is immunologically mediated and has a role in the pathogenesis of autoimmune thrombocytopenias.

Treatment of adult autoimmune thrombocytopenic purpura with high-dose intravenous plasmin-cleaved gammaglobulins

We present the results of the treatment of 15 adult patients with chronic autoimmune thrombocytopenic purpura with high dose i.v. gammaglobulins. In 11 patients, this treatment produced a remission, complete (platelet counts above 100 X 10(9)/l) in 5, partial (platelet counts between 50 and 100 X 10(9)/l) in 6. In all these patients, the response was transient lasting 2-4 weeks. In 4 patients, no response was observed. We used plasmin-cleaved gammaglobulins which caused rare and mild side effects and gave results similar to those reported with intact human gammaglobulins. The indications of high dose i.v. gamma-globulins in the management of adult patients with autoimmune thrombocytopenic purpura are discussed.

Danazol for the treatment of idiopathic thrombocytopenic purpura

Idiopathic thrombocytopenic purpura is an autoimmune disorder, most common in young women. We treated 22 patients with this disorder (12 of whom were women) with danazol, an androgen with reduced virilizing capability, for two months or longer. Fifteen had undergone splenectomy, all were receiving glucocorticoids, and 18 had also been given other treatments. Fifteen of the patients were benefited, 11 with sustained normalization of their platelet counts. Six of eight patients tested had initial increases in circulating platelet-reactive IgG; in all six there was a marked decrease concomitant with danazol therapy. Danazol was effective in both men and women, irrespective of previous treatments. The duration of remissions ranged from 2 to 13 months. The drug was well tolerated and appears to be better suited than glucocorticoids for long-term management of idiopathic thrombocytopenic purpura, but the exact indications for the use of danazol in this disorder remain to be determined.

Treatment of idiopathic thrombocytic purpura in pregnancy by high-dose intravenous immunoglobulin

ITP in pregnancy may lead to fetal thrombocytopenia caused by the transplacental passage of maternal antiplatelet antibody. The most hazardous complication in the infant is intracranial hemorrhage. In addition ITP in pregnancy is reported to be associated with an increased abortion rate and an elevated fetal morbidity and mortality. Therefore obstetric management must aim at increasing maternal and fetal platelets. Several therapeutic approaches to the treatment of ITP in pregnancy are evaluated. Two cases of ITP in pregnancy are reported. Administration of high-dose intravenous immunoglobulin is introduced as a new therapy for ITP in pregnancy. The rapid reversal of thrombocytopenia following immunoglobulin G administration suggests that it is useful especially as emergency treatment for ITP in pregnancy.

[Primary biliary cirrhosis and idiopathic thrombopenic purpura. A new association]

A case of primary biliary cirrhosis with stage III histological changes associated with an asymptomatic thrombocytopenic purpura with raised antiplatelet antibody levels is described. This new association of two conditions in which an autoimmune participation is generally accepted suggests a predisposition to this form of disease and/or the intervention of common trigger factors; however, an analysis of known etiological mechanisms does not exclude the possibility of a fortuitous association.

Antibodies reactive with surface membranes of cellular elements in the blood

Autoreactive antibodies or immune complexes may accelerate clearance of mature erythrocytes, leukocytes, and platelets from the circulation in patients with rheumatologic and immunologic disorders. The most compelling evidence for immune injury to hematopoietic cells exists in patients with systemic lupus erythematosus and patients with Felty's syndrome and its variants. These disorders may also cause tissue inflammation, which in turn commonly results in underproduction of erythrocytes and development of thrombocytosis. However, recent evidence indicates that underproduction of hematopoietic cells may also result from immune injury to cellular elements in the bone marrow. In many laboratories, sensitive techniques are now clinically available for the detection of cell-associated immunoglobulin and complement. These assays have helped confirm the role of antibody in the pathogenesis of autoimmune hemolytic anemia and idiopathic thrombocytopenic purpura. However, recent data indicate that there is probably a continuum between the amount of immunoglobulin and complement found on normal cells and that found in a variety of disease states. In several of these disorders, additional evidence will be required to establish that the increase in cell-bound immunoglobulin leads to a decrease in the life-span of the cell. In order to provide significant help to the clinician managing an individual patient, these serologic tests must be capable of identifying the portion of the cell-associated protein actually involved in the destructive process. The availability of monoclonal reagents capable of identifying restricted regions on cell-bound immunoglobulin may help identify molecules bound specifically as antibody and may help identify the antigens involved in autoimmune disorders.

Autoimmune thrombocytopenic purpura. Comparison of three different methods for the detection of platelet antibodies

An evaluation of three techniques for detection of antiplatelet antibodies in ATP is made. The platelet factor 3 availability after immunoinjury and the immunohystochemical technique using immunoperoxidase were more sensitive than 14C-5HT release from platelets for this purpose. The percentage of positive cases was similar in acute and chronic ATP patients while it significantly fell in cases in remission. A high proportion of patients in clinical remission had normal platelet aggregation, despite the persistence of antiplatelet antibodies.

Platelet antibody levels do not correlate with response to therapy in idiopathic thrombocytopenic purpura

Platelet bound antibody was measured at presentation in 67 patients with idiopathic thrombocytopenic purpura by means of a quantitative antiglobulin consumption technique. The amounts of antibody present on the platelets of patients who failed steroid therapy were similar to those present on the platelets of patients who achieved a remission of their illness. It was also not possible on the basis of these data to identify those patients whose illness would remit after splenectomy. It is concluded that the pretreatment platelet antibody level does not assist in predicting the responses to treatment.

Platelet-associated immunoglobulin G in childhood idiopathic thrombocytopenic purpura

Platelet-associated IgG was studied in children with acute and chronic ITP and in patients with thrombocytopenic SLE, using the microtiter solid-phase radioimmunoassay. Of the children with acute ITP, 85% had elevated PAIgG levels. The degree of elevation of PAIgG at onset of disease did not correlate with the development of chronicity. Of the children with acute ITP, clinically and hematologically indistinguishable from the rest, 15% had normal PAIgG values. All of 22 children with chronic ITP had elevated PAIgG values. Although there was good correlation between the platelet count and the PAIgG value in children with chronic ITP, the association was not as striking in those with acute ITP; thus, factors in addition to the level of PAIgG may contribute to the thrombocytopenia in the latter group. Patients with SLE and thrombocytopenia had higher values of PAIgG than would be predicted from the platelet count; the PAIgG value is probably not the only factor determining the degree of immune thrombocytopenia.

Monomeric IgG preparations for intravenous use inhibit platelet stimulation by polymeric IgG

Seven different immunoglobulin G (IgG) preparations for intravenous use were tested for their capacity to inhibit serotonin-release from washed human platelets induced by IgG coupled with bis-diazobenzidine. Using a reference standard consisting of the top third fraction of an ultracentrifuged gammaglobulin preparation for intramuscular use, two chemically treated preparations were less potent inhibitors than the standard while two preparations, one pH 4 treated and another albumin protected, were better inhibitors. A pepsin treated preparation was devoid of inhibitory capacity, whereas Fc fragments derived from human IgG were extremely efficient. Evidence is discussed that the inhibitory capacity is inversely correlated to the content of oligo- and/or dimeric IgG molecules.

High-dose intravenous IgG in adults with autoimmune thrombocytopenia

A study of the effect of high-dose intravenous IgG in 25 adults with autoimmune thrombocytopenia confirmed the predictable rise in the platelet count seen during the infusion and previously reported in children. Unlike the data based on children, there was no sustained response unless the IgG infusion was closely associated with splenectomy. There was no correlation between the presence of platelet autoantibodies or the Ig class of the autoantibody and the pattern of response to the infusion. The initial platelet response appears to be the result of transient blockade of the reticuloendothelial system, including the macrophage Fc receptor mechanism. The long-term response in some patients requires another explanation and may be due to a more specific immunosuppressive effect of the high-dose IgG infusion. Splenectomy may have an additive effect by removing a major site of platelet autoantibody production.

The value of platelet-associated IgG in predicting the efficacy of splenectomy in autoimmune thrombocytopenia

In a prospective study, the hypothesis of whether the quantitative determination of platelet-associated IgG (PAIgG) in patients with chronic autoimmune thrombocytopenic purpura (ATP) can predict the efficacy of splenectomy, was investigated. PAIgG levels were repeatedly determined in 16 patients with definite ATP pre- and postsplenectomy, and related to platelet counts and platelet mean life span. It was found that patients with an immediate remission after splenectomy tended to have lower PAIgG levels (less than 6%) than failures, but this difference was not statistically significant. We conclude that PAIgG is of limited value for the prediction of the efficacy of splenectomy in ATP.

The prenatal prediction of thrombocytopenia in infants of mothers with clinically diagnosed immune thrombocytopenia

The management of the pregnant patient with immune thrombocytopenia is complicated by the unavailability of the fetal platelet count. Since the transplacental passage of antiplatelet antibodies mediates infant thrombocytopenia, measurement of maternal platelet-associated IgG might predict infant outcome. We related the maternal platelet count and platelet-associated IgG level to the infant's platelet count in 41 pregnancies in 38 patients who were clinically diagnosed as having immune thrombocytopenia. Fifteen of 39 live-born infants were thrombocytopenic at delivery. Maternal platelet-associated IgG was predictive of infant platelet count but maternal platelet count was not; only one of the 20 infants delivered of the 18 thrombocytopenic mothers with normal platelet-associated IgG was affected, whereas 11 of 12 thrombocytopenic mothers with elevated platelet-associated IgG had thrombocytopenic infants. Five infants died in utero between 18 and 28 weeks' gestation, but otherwise there was no significant morbidity in the live births. Measurement of platelet associated IgG in mothers with immune thrombocytopenia during pregnancy can be used to predict infant thrombocytopenia, although it does not predict the severity of the thrombocytopenia.

Diagnostic and prognostic significance of platelet-bound IgG measurement in immune thrombocytopenic purpura

The test proposed by Dixon et al. is an important contribution to the technique for detection of platelet-associated antibody. This test measures platelet-associated IgG by a complement-mediated red blood cell lysis-inhibition technique. We have used the direct Dixon test to study 44 cases of immune thrombocytopenic purpura and 90 controls, including subjects with nonimmune thrombocytopenic purpura and healthy subjects. Increased PAIgG was noted in 86.3% of ITP patients. However, the pretreatment values of PAIgG were not helpful for predicting the therapeutic response to either prednisone or splenectomy. Six patients in long-term clinical remission had normal platelet counts and distinctly abnormal PAIgG values. This condition was associated with qualitative platelet functional defects. This latter finding seems to be of diagnostic interest and deserves further investigations.

Platelet associated IgG, platelet survival, and platelet sequestration in thrombocytopenic states

Platelet-associated IgG (PAIgG), platelet mean life span (MLS), and platelet sequestration sites were studied in 69 patients with immune (ITP) and presumed nonimmune thrombocytopenias (NTP). A shortened MLS was associated with elevated PAIgG (N = 46), and with normal PAIgG (N = 15). Four patients had a normal MLS, but elevated PAIgG, four patients were normal for both parameters. The highest PAIgG values occurred in ITP patients with a very short MLS. Nine NTP patients had also elevated PAIgG, but a normal or slightly shortened MLS. There was a significant double log correlation between PAIgG and MLS for ITP, but not for NTP patients. Judged from the coefficient of determination, only 10% of PAIgG were directly related to a shortened MLS. 70% of patients (N = 63) had exclusively splenic and 30% hepatosplenic sequestration. PAIgG was elevated in 29/44 patients with splenic (66%) and in 16/19 patients with hepatosplenic sequestration (84%). In ITP, PAIgG-positive cases were observed in 69% of splenic v 82% of hepatosplenic sequestration, while in NTP the corresponding figures were 6/11 and 2/2. No significant correlation between PAIgG and either sequestration type was demonstrable. We conclude that in immunologically mediated thrombocytopenia only a small portion of PAIgG accounts for a decreased MLS, and that the concentration of PAIgG per se does not determine the platelet sequestration type.

Effects of source leukocyte collection on the immune system

This study was initiated in order to assess any immunologic effects that source leukocyte concentrate collection might have on double-bag plasmapheresis donors. Previous studies have shown that surveillance parameters, such as T versus non-T lymphocyte subpopulations, showed no abnormal values in donors with as many as 500 visits over a 12-year period. The present study demonstrates that the frequency and the total number of leukocyte donations do not effect the lymphocyte subpopulations and functions observed. No significant changes were noted for specific and nonspecific stimulation, natural killer (NK) cell activity, lymphocyte surface markers and a variety of functional parameters. For example, the apheresis donors manifested no differences in NK cell activity, human leukocyte interferon production, IgG synthesis by B cells and percent suppression of both IgG synthesis and mixed lymphocyte cultures, when compared to non-apheresed donors.

Transient reversal of thrombocytopenia in idiopathic thrombocytopenic purpura by high-dose intravenous gamma globulin

Since recent observations indicate that treatment with high-dose intravenous polyvalent intact immunoglobulin leads to a rapid reversal of thrombocytopenia in the idiopathic thrombocytopenic purpura (ITP) of childhood, we decided to apply this treatment to adults with ITP and to test the possibility that the effect of the immunoglobulin might be attributable to transient blockade of the reticuloendothelial system. Using sequential clearance studies of autologous 99mTc-labeled and anti-Rh(D)-sensitized erythrocytes in four adults with ITP who were treated with total doses of 1 to 1.5 g of immunoglobulin per kilogram of body weight, we found that a transient rise in platelet counts to normal levels within four to five days was accompanied by a marked temporary prolongation of the immune-particle clearance time. These data suggest that commercial intravenous immunoglobulin preparations may interfere with phagocyte Fc-receptor-mediated immune clearance. Since platelets in ITP treated with immunoglobulin were fully hemostatic, this type of therapy may allow surgical procedures to be performed safely in patients with this disease.

Immune thrombocytopenic purpura and pregnancy

Neonatal thrombocytopenia is a potentially life-threatening complication of immune thrombocytopenic purpura (ITP). We followed 23 pregnant women who had either a history of ITP (11 women) or clinically active disease (12 women) to delineate the factors responsible for neonatal thrombocytopenia. No relation was observed between maternal and neonatal platelet counts (P greater than 0.5). Eleven women delivered thrombocytopenic children; antiplatelet antibodies were detectable in each mother, including five who were in clinical remission at delivery. The level of platelet-associated IgG in the mothers did not identify the neonates at risk for thrombocytopenia (P greater than 0.05). However, the level of maternal circulating antiplatelet antibody correlated with both the presence and the extent of neonatal thrombocytopenia (P less than 0.005). A discrepancy between maternal platelet count and maternal antibody level may be especially notable in mothers treated with steroids or splenectomy. Monitoring the level of circulating antiplatelet antibody may help in identifying and managing pregnant women with ITP at risk of delivering neonates with serious thrombocytopenia.