Immune response of lymphocytes from patients with multiple sclerosis to phytohemagglutinin, basic protein of myelin and measles antigens

Women who contributed to past research in multiple sclerosis

BACKGROUND

The history of multiple sclerosis (MS) is dominated by the discoveries of famous men. However, women would like to feel part of the story and to know that women have contributed to MS research.

OBJECTIVE

To identify women who contributed to the history of discovery in MS.

METHOD

This was a personal survey from my knowledge of previous work.

RESULTS

There were no women participants in the early stages of MS research. However, since 1950 there are many women who have contributed to MS research. In the 20th century, there were famous women who contributed to the scientific fields that form the basis of MS research. In the 21st century, more women participate in MS research but studies suggest that they are under-represented in positions of prominence.

CONCLUSION

Women have been part of the effort to understand MS, but are not well recognized.

A reconsideration of the measles-adherent leukocyte phenomenon and multiple sclerosis

Some studies have shown that more mononuclear leukocytes (MNLs) from multiple sclerosis (MS) patients adhere to cells persistently infected (PI) with measles virus than do MNLs from controls. Some studies have shown no difference in adherence. It is suggested that the conflict between studies is merely technical. The net effect of this conflict has been to obscure the possibility of cell surface differences which underlie this adherence phenomenon and discourage further investigation of them. Given the current interest in the molecular basis of cell-cell adhesion and the new methods and reagents available to study it, the problem of identifying cell surface differences between normal and MS leukocytes can now be more readily approached. An investigation of the MS MNL cell surface using these new methods is suggested.

Antibodies to myelin basic protein and measles virus in multiple sclerosis: precursor frequency analysis of the antibody producing B cells

Antibody-producing B lymphocytes were polyclonally activated and transformed, by Epstein-Barr virus (EBV), into multiple B lymphoblastoid cell lines in a microculture system. The frequencies of B precursor cells producing antibodies to myelin basic protein (MBP) and measles virus were analyzed in peripheral blood of patients with multiple sclerosis (MS) and control subjects. Measles virus-specific B cells were detected at a significantly higher frequency in MS patients (n = 10, P less than 0.005) than patients with other neurological diseases (n = 10) and normal subjects (n = 10). In contrast, the frequencies of B cells producing anti-MBP antibodies and natural antibodies did not differ statistically among the three groups tested (P greater than 0.05). In addition, the anti-MBP antibodies produced by a panel of stable B cell lines obtained were found to react selectively with an epitope(s) within the C-terminal half fragment 90-171 of the human MBP molecule. In our experiments, no antibody cross-reactivity between MBP and measles virus could be detected in a total of 2760 B cell cultures.

Lymphocyte activation in discordant multiple sclerosis twin pairs

Phytohemagglutinin-induced lymphocyte activation sequence was studied in monozygotic and dizygotic discordant multiple sclerosis (MS) twin pairs in a quiescent disease phase. The study group included all available 11 pairs listed in a nation-wide twin register. Lymphocyte activation markers, DNA synthesis and gamma-interferon secretion were studied using avidin-biotin-peroxidase complex (ABC) stainings, [3H]thymidine incorporation, and a solid-phase double-antibody immunoradiometric assay (IRMA), respectively. The level and kinetics of interleukin-2 receptor expression, DNA synthesis, gamma-interferon secretion, and major histocompatibility complex (MHC) locus II antigen expression were similar (Wilcoxon's test for paired samples) in both the diseased and healthy monozygotic and dizygotic twins. Our results suggest that the cell-mediated immune system may not be primarily at fault, but rather that both MS itself and its exacerbations are caused by an unknown triggering stimulus facing a properly functioning immune system.

Cell-mediated immunological status in multiple sclerosis patients

In vitro lymphocyte proliferation in response to allogeneic pooled cells, mitogens (PHA, Con A and PWM), and PPD was measured in 67 patients with clinically definite MS and in 67 age and sex-matched controls. Overall, dose-response curves in the two groups were similar, but response to PHA and PWM was significantly greater among patients, and a greater percentage of patients failed to respond to peak and suboptimal PPD concentrations. There was a reduced response to allogeneic pooled cells in Dw2 positive controls, and, in both patients and controls, a tendency towards a higher PPD response in Dw2 positive males. The results suggest that there is some alteration of balance of immune regulation in MS, which is slightly affected by Dw2 status.

T-cell subsets in multiple sclerosis: lack of correlation between helper and suppressor T cells and the clinical state

Peripheral blood T-lymphocyte subsets were investigated in a group of 26 multiple sclerosis (MS) patients of different clinical categories and compared to those of 15 normal controls and 7 other patients with known immunoregulatory disorders. In addition 17 well-documented acute relapses in 11 MS patients were also studied, some of whom were tested serially prior to, during, and after the acute attack. Using three different commercial preparations of monoclonal antibodies directed against human T3, T4, and T8 lymphocyte markers, none of the MS patients irrespective of disease category exhibited any changes in the absolute numbers of T-cell subsets or ratios thereof; this was true during either quiescent or active stages of the disease. In contrast, several patients with known immunoregulatory disorders exhibited clear changes in T4/T8 ratios. Factors such as type of patient studied, sampling error, and methods of isolation of mononuclear cells, as well as source of monoclonal antibody, failed to explain the lack of change in T-cell subsets in these patients. Thus, our data fail to confirm the previous reports of a decrease in the absolute numbers of T8 cells or the increase in the T4/T8 ratios in active or quiescent MS patients. These negative findings underscore the need for further studies relating these markers to meaningful functional properties of these cells and their interaction with the relevant target organs.

Medullasin activity in granulocytes of patients with multiple sclerosis

Medullasin activity in mature granulocytes was measured in the blood of 22 patients with multiple sclerosis (definite type, 16; probable type, 6). The activity was elevated in every patient in relapse; it decreased to nearly normal levels at the beginning of improvement and further decreased to normal levels with remission. Serial determinations of the level of medullasin activity in 3 patients revealed that activity increased several days before the onset of acute exacerbation. Medullasin activity level in mature granulocytes obtained from patients with neurological diseases other than multiple sclerosis was largely within the normal range, except in 2 patients with spinocerebellar degeneration. Measurement of medullasin activity in mature granulocytes may become useful in both diagnosis and evaluation of multiple sclerosis.

Lymphocyte blast transformation responses to mitogens and specific antigens in different clinical phases of multiple sclerosis: a follow-up study

28 MS patients were studied at least 5 times for lymphocyte blast transformation responses to several mitogens (PHA, Con, PWM) and specific antigens (PPD, herpes simplex, measles, mumps, rubella), the mean duration of the follow-up being 15.3 months. Comparison of responses during remissions, exacerbations and ACTH treatment revealed no straight-forward association between the strength of response and clinical disease activity. Mitogen responses did not differ among various disease phases, but the PPD response was significantly lower during exacerbations than during remissions and still lower during ACTH treatment (P less than 0.05, Wilcoxon paired test). In responses to viral antigens, there was the same trend as in the PPD response. However, there were great individual differences in the behaviour of all antigen and mitogen induced lymphocyte responses. As a group, MS patients also showed more changes in their PHA mitogen responses during the follow-up than 8 control subjects followed similarly (P less than 0.005, F-test). The variation coefficient of the PHA response was also correlated with the maximal difference in the Fog neurologic deficit scale during the follow-up time (r = 0.460, P less than 0.05). However, patients with greatest clinical changes most often also received ACTH treatment, which may affect the results. The follow-up results of individual patients revealed that some had quite regular patterns of decreasing responses during disease relapses, whereas others had more irregular wide fluctuations of responses.

The significance of abnormal immune responses in patients with multiple sclerosis

Early diagnosis of multiple sclerosis (MS) may be assisted by tests for the abnormal immune responses of the central nervous system (CNS) including oligoclonal IgG bands in the cerebrospinal fluid (CSF), increased CNS IgG synthesis, increased CNS antibody synthesis against multiple viruses and increased numbers of enlarged lymphoid cells in the CSF. Alterations in immunological responses are important in the pathogenesis of MS. Further studies are needed, however, to identify the antigen(s) and/or antibodies responsible for oligoclonal IgG in the CSF of MS patients. Also, the cause(s) for the other immunological abnormalities with diagnostic importance need to be identified. The increased synthesis of antibodies against multiple unrelated viruses suggests generalized alteration in the immune regulatory system. The etiology of MS might be multifactorial involving abnormal immunological responses, possibly precipitated by infectious agents acquired during childhood by genetically susceptible individuals. The immunological responses including alterations in myelin basic protein concentration, antimyelin antibody and immune complex activities in CSF, and in vitro stimulation, suppression and migration inhibition of blood lymphocytes appear to correlate with stage of MS and severity of CNS damage. Some of the tests may become useful in estimating the prognosis of the disease. Longitudinal studies are needed to clarify the sensitivity of the diagnostic and prognostic immunological tests and etiological significance of these abnormalities in MS.

Abnormal regulation of in vitro IgG production in multiple sclerosis

A pokeweed mitogen-stimulated IgG synthesis assay was used to evaluate T suppressor cell function in peripheral blood lymphocytes (PBL) obtained from multiple sclerosis (MS) patients. Autochthonous cultures of fractionated and recombined MS B and T cells exhibited less suppression of IgG synthesis than similar cultures of PBL from control subjects. No difference occurred in the levels of suppression among MS patients grouped according to disease states. When allogenic cultures of MS B and normal T cells or normal B and MS T cells were compared to autochthonous cultures of control cells, no differences were observed. The results suggest that the lower levels of suppression observed in autologous MS cell cultures are not a result of T suppressor cell dysfunction alone.

Lymphocyte blast transformation responses and viral antibodies in relation to HLA antigens in multiple sclerosis

Fifty four clinically stable multiple sclerosis (MS) patients and 54 age- and sex-matched control subjects were HLA-typed, and their responses to herpes simplex, measles, mumps and rubella antigens were examined by the lymphocyte blast transformation test and by serum antibody titrations. Blast transformation response to purified tuberculin (PPD), mitogen phytohaemagglutinin (PHA), pokeweed mitogen (PWN) and concanavalin A (Con A) and spontaneous proliferation of lymphocytes were also studied. MS patients differed from controls by higher antibody levels to measles and rubella viruses and by lower specific blast transformation responses to rubella and measles antigens. When the relative strength of transformation responses was measured, mumps and herpes simplex responses were also lower in MS patients than in controls. In addition, spontaneous lymphocyte proliferation of MS patients in 6-day cultures was lower than that of control lymphocytes. In mitogen stimulations there were no differences between whole groups, but the oldest patients had lower responses to PHA and Con A than their matched controls. The frequency of HLA-Dw2 was 56.6% in MS patients and 32.1% in controls. The patients with and without Dw2 differed from each other only by a lower specific response to PPD in the Dw2-positive group. The immunological response of Dw2-positive controls resembled that of MS patients: low transformation response to viral antigens, low spontaneous proliferation and elevated measles antibodies. This finding supports the function of a genetically determined type of immune responsiveness with low cell-mediated immunity and high levels of certain viral antibodies as one susceptibility factor in multiple sclerosis.

Lymphocyte blast transformation responses in measles infection

Lymphocyte blast transformation responses were studied in eight patients with natural measles infection. A specific response to purified measles virus antigen and a weaker response to crude measles virus antigen were found after infection. The response to purified measles antigen appeared 1-3 weeks after the beginning of the rash, when the great number of proliferating mononuclear cells found in the peripheral blood during the rash was declining. In the first weeks after onset of the rash also leucocyte and lymphocyte numbers were decreased, and specific responses to purified tuberculin (PPD) and to rubella and mumps virus antigens were suppressed. In mitogen stimulation tests there was no significant suppression of phytohaemagglutinin and concanavalin responses in this small series, but the response to pokeweed mitogen was decreased. The responses to antigens other than measles virus antigens recovered in parallel with the increase of the measles-specific response.

Lymphocyte transformation in the presence of myelin basic protein in multiple sclerosis and control subjects

The transformation of lymphocytes in vitro in the presence of human myelin basic protein has been investigated in normal people, patients with multiple sclerosis (MS) and controls with other neurological diseases. There was little or no response at low concentrations (1--10 microgram/ml) but significant transformation at higher concentrations (100--1000 microgram/ml) in all three groups. There was no significant difference among the groups as a whole, but those MS patients who had had disease for more than 10 years did show greater responses than normal subjects (P less than 0.05). Increased responses could not be correlated with any other aspect of disease activity: in particular they were not increased in patients with acute relapses. The use of autologous serum instead of homologous AB Rhesus positive serum did not significantly alter lymphocyte responsiveness. The absence of any response in the presence of purified calf thymus histone suggests that the response to myelin basic protein indicates a low level of lymphocyte sensitization to this antigen even in normal subjects. The present evidence does not support a primary pathogenetic role for such a reaction in MS. The increased response in patients with a long duration of disease might merely be an effect of white matter damage or might represent an amplification of the normal immune response contributing to myelin breakdown and leading to the emergence of the progressive stage of the disease. The study of lymphocyte responsiveness over a wide range of concentrations of myelin basic protein is considered to resolve some of the controversy surrounding this subject in the literature.

Myelin basic protein binding cells in active multiple sclerosis

A sensitive, antigen-specific rosetting technique was used to enumerate blood cells that bind myelin basic protein (BP) in MS patients and controls. Sixteen of 23 MS patients in exacerbation but only 7 of 48 in remission formed elevated numbers of rosettes. Five of the latter 7 patients had recovered from an exacerbation within four months of the laboratory evaluation. Eight of 20 patients with progressive MS, all of whom had had disease for more than four years, had BP rosette-forming cells. None of the 16 normal volunteers and 1 of 8 neurological controls had BP rosette-forming cells. These results suggest that BP-binding cells in MS are confined to patients in acute exacerbation or within four months of activity, and those who have had progressive disease for at least four years.

Delayed hypersensitivity to human encephalitogenic protein as assayed by agarose leucocyte migration in multiple sclerosis patients

Using a leucocyte migration test (Clausen's direct agarose gel migration method) hypersensitivity to human encephalitogenic protein has been examined in 50 multiple sclerosis patients (group 1), 50 healthy persons (group 2) and 25 patients with other neurological diseases (group 3). In group 1, 30 MS patients (60%) show an abnormal migration index, manifested either as inhibition or stimulation of migration; 29 controls in group 2 (58%), 11 O.N.D. patients in group 3 (44%) show an abnormal migration index. These results mean that lymphocyte hypersensitivity to myelin basic protein appears neither to be constant nor specific to multiple sclerosis. Three migration index curve types at different antigen concentration are obtained: monophasic curves within the normal index zones; monophasic curves staying in the inhibition or stimulation zone and biphasic curves with dose-effect relationship. Whatever the antigen used, this dose-effect relationship implies that the test must be carried out at different concentrations. The meaning of spontaneous sensitisation in healthy controls is discussed.

Influence of measles virus antigen on leukocyte migration in multiple sclerosis and controls

The leukocyte migration inhibiton test was used in multiple sclerosis patients and in healthy controls for investigation of sensitization of blood lymphocytes against preparations of measles virus, mumps, NDV virus, and PPD. Regardless of antigen used, no significant differences were found between the groups. There was a strong correlation between the leukocyte migration inhibition obtained with measles virus antigen and with PPD. The leukocytes from MS patients as well as from healthy controls showed a significantly more pronounced inhibiton when a Tween 80 and ether-treated preparation of measles virus was used, compared with the whole measles virus antigen. No correlations were found between the degree of leukocyte migration inhibition and the antibody titers against different components of measles virus in individual samples.

Cell-mediated hypersensitivity in multiple sclerosis and other neurological diseases

Using a direct macrophage migration inhibition test the hypersensitivity against encephalitogenic protein and phytohaemagglubinin in normal persons, multiple sclerosis patients and patients with other diseases of the central nervous system were examined. It proved that the vast majority of patients were sensitised to brain antigen. The percentage of positive tests and the percentage of migration inhibition was related to the activity of the disease. No differences were found between lymphocytes of multiple sclerosis patients and of patients with the other neurological diseases patients. Foetal calf serum was proven to depress the hypersensitivity to phytohaemagglutinin as did multiple sclerosis serum on normal lymphocytes. The results did not support the hypothesis that multiple sclerosis is caused by a cell-mediated auto-immune process.

In vitro cell-mediated immunity of cerebrospinal-fluid lymphocytes to myelin basic protein in primary demyelinating diseases

In an attempt to characterize the immunologic reactivity of cerebrospinal-fluid lymphocytes in demyelinating diseases, we compared the myelin-basic-protein-induced in vitro responses of these cells to peripheral blood lymphocytes from the same subjects with a variety of neurologic diseases. Peripheral blood lymphocytes from patients with acute disseminated encephalomyelitis and progressive multiple sclerosis had increased reactivity as compared to those of normal volunteers (P less than 0.01 and P less than 0.05, respectively). Cerebrospinal-fluid lymphocytes from patients with acute disseminated encephalomyelitis and acute and progressive (but not stable) multiple sclerosis were more reactive than cells from subjects with other neurologic diseases (P less than 0.005, P less than 0.02 and P less than 0.05, respectively). Cerebrospinal-fluid lymphocytes manifested a greater reactivity than peripheral blood lymphocytes in acute and progressive multiple sclerosis but not in acute disseminated encephalomyelitis. These findings demonstrate that lymphocytic cells reactive to myelin basic protein are present in the spinal fluid during active demyelinating disease; and that these cells may be more reactive than peripheral blood lymphocytes.

Biochemical findings in multiple sclerosis. V. Transformation of lymphocytes from patients with multiple sclerosis by human basic protein

Lymphocyte stimulation tests with human basic protein of myelin were performed on patients with multiple sclerosis, with other neurological diseases and on normal subjects. In both MS and OND group, a hypersensitization to basic protein was seen in about one third of the cases. All normal subjects, except one, had negative responses. In the MS group, a positive correlation could be found with some features of the disease: significantly more positive responses were found in independent patients with a short duration of illness and in those with an oligoclonal distribution in the CSF. The authors compare their results with those of the literature. The possible role of BP in pathogeny of MS and OND is discussed.

Spontaneous and PHA stimulated lymphocyte transformation in multiple sclerosis patients during and after acute exacerbations with special reference to steroid therapy

Spontaneous (SLT) and phytochemagglutinin (PHA) stimulated lymphocyte transformation was studied in multiple sclerosis (MS) patients suffering from acute exacerbations or from the chronic progressive type of MS. The changes in cell-mediated immunity were also observed before, during and after immunosuppressive (prednisone) treatment. A total of 85 venous blood samples from 23 MS patients (11 males, 12 females) were included in the material. The controls consisted of 25 measurements from 17 healthy volunteers who served as normal controls. The pathological controls consisted of 13 patients with neurological diseases other than MS. All these and MS patients were hospitalized. The IUFdR uptake of the cells of MS patients was more rapid than that of the controls at 1-hr incorporation time in SLT. The difference decreased and was eliminated by longer incubation times (2-4 hrs). MS patients also differed from pathological controls in this sense. The reaction to PHA stimulation was lower both in the MS groups (64 per cent from the normal controls) and in the pathological controls. Within the different MS groups, significantly lower values were seen only in the samples of the patients receiving immunosuppressive therapy. Under prednisone (80-100 mg initial dosis) PHA stimulation values rapidly dropped within the first week and slowly returned within 2-4 weeks after the stopping of the corticosteroid treatment. In some cases, however, PHA values remained at a low level for several months. The significance of this finding for the understanding of the underlying pathogenetic mechanisms has to be studied in more detail.

Effect of encephalitogenic protein on migration in agarose of leukocytes from patients with multiple sclerosis. Variable effect of the antigen in a large dose range, with a literature review

The literature on in vitro test of sensitivity to brain antigen in multiple sclerosis is summarized in the tables. A study is presented using leukocyte migration in agarose as test system and a wide range of concentration of bovine encephalitogenic protein as antigen. Definite reactivity was seen in 12 out of 28 patients with MS. Some occurred in patients who had had no signs of disease activity for at least 5 years. Reactivity occurred more often in patients with active disease studied within 5 days after a relapse. The significance of the in vitro reactivity is briefly discussed.

[Demonstration of a factor in cerebrospinal fluid with inhibitory activity for electrophoretic cell mobility in multiple sclerosis (author's transl)]

Inhibition of electrophoretic cell migration using cerebrospinal fluid (CSF) directly was investigated by the modified MEM (macrophage electrophoretic mobility) and TEEM (tanned sheep erythrocyte electrophoretic mobility) tests, respectively. An inhibitory activity of macrophage slowing factor (MSF)--one of in vivo lymphokines--in CSF was established in cases of multiple sclerosis (17.5 +/- 3.8%), and neurolues. The value of this MSF assay turned out to be significantly different from the remaining inflammatory ailments of the nervous system (10.1 +/- 6.8%). Results of other neurological diseases were found to be very much lower (5.1 +/- 4.2%). It seems important, for immunopathogenesis and the diagnosis of neuroimmunological diseases with enhanced cellular immunoreaction, to evaluate MSF activity in CSF. To characterize the active factor in CSF (and serum) these fluids were fractionated by gel filtration chromatography as well as supernatants from lymphocyte-antigen incubation in MS patients. The main activity for inhibition of electrophoretic cell mobility was eluated in the same fraction in these fluids. It could be shown that units have a molecular weight of about 15000 Daltons; this value for MSF lies below those for other inhibitory lymphokines.

Direct leukocyte migration inhibition in multiple sclerosis--a possible assessment of activity

Twenty-four patients with multiple sclerosis were evaluated and classified according to their clinical state. Specific migration inhibition studies were carried out on blood samples from each using myelin basic protein, an acid soluble protein fraction isolated from normal human CNS white matter, and multiple sclerosis myelin basic protein isolated from patients who had the disease, as the antigenic material. This test system employed selected media. Results were compared with those of normal controls and patients with other neurological disease states. Antigen concentration of 500 mu g/ml in serum free medium combined to produce the greatest inhibiting effect on leukocytes in patients with apparent multiple sclerosis and differentiated these patients from those in the other groups tested. Leukocytes in patients who had probable multiple sclerosis with partial impairment, signifying possible current activity of the disease, were especially inhibited as compared to the leukocytes from other groups tested against myelin antigen. Cerebrospinal fluid from affected patients when used as a media enhanced the test. This study suggests that migration inhibition of peripheral leukocytes using myelin protein may be useful in the diagnosis of patients with multiple sclerosis. There is additional evidence that the degree of leukocyte migration inhibition may reflect activity of the disease with its consequent implications on treatment and prognosis.

Lysolecithin fusion of cells from multiple sclerosis patients with Vero cells

Investigations were performed on cell cultures derived from patients with multiple sclerosis (MS) in order to trace a possible virus infection as a cause of the disease. Cell cultures were established from one brain autopsy specimen and four lymph node biopsies from MS patients. Lymphocytes from 28 MS patients and six healthy controls were used for fusion or cocultivation experiments, either immediately after isolation or after mixed lymphocyte cultures (MLC). Lysolecithin fusion and cocultivation experiments were made with Vero cells and with, respectively: cultured brain cells, lymph node cells and lymphocytes from MS patients. Electron microscopical examination revealed intranuclear filamentous structures in 5 per cent of the cells in primary cultures of MS brain and lymph node and in control skin organ cultures. Multinucleated cells were found in six out of 19 cocultures of Vero cells and MS lymphocytes preincubated for 2 days at 37 degrees C. The cultures were tested for the presence of viruses, i.e. measles virus and virus producing hemadsorption with human type O and/or guinea pig erythrocytes and virus against which the MS patients showed serum FA-antibodies. No virus antigen could be demonstrated in the cells.

Effect of encephalitogenic protein on the migration in agarose of leucocytes from patients with multiple sclerosis. Correlations with clinical parameters, localization of antigenic determinants, and influence of corticotrophin treatment

We have extended the results from our previous investigation of the reactivity of leucocytes from patients with multiple sclerosis and some other neurological diseases to bovine encephalitogenic protein, using the migration in agarose technique. 1. Reactivity (i.e. behaviour in the test deviating from that expected with cells from healthy subjects) is manifested either as an enhancement or an inhibition of leucocyte migration. 2. The incidence of subjects with cells showing reactivity to encephalitogenic protein is higher in the group of patients with multiple sclerosis than in the group of patients with other neurological diseases. 3. Reactivity to encephalitogenic protein is correlated to disease course score; patients with a chronic progression of the disease show the strongest reactivity in the test. 4. The tryptophan-containing region of the encephalitogenic protein appears to be a major determinant of significance for this test. 5. Patients tested during corticotrophin treatment tend to show a higher degree of reactivity in the test than expected-the increased reactivity seems to be primarily directed to the tryptophan-containing region.

The synthesis of prostaglandins in platelets from patients with multiple sclerosis

As a continuation of our previous studies on the synthesis of prostaglandins (PGs) in human thrombocytes, the present study concerns the biosynthesis of PGs in thrombocytes from patients with multiple sclerosis, as this condition has been suggested to be linked to thrombotic and/or thrombocyte abnormalities. It was found that in these patients a statistically decreased synthesis of PGE1, PGE2 and PGF took place compared to the corresponding values in normal subjects. The ratio between PGE1 and PGE2 was, however, unchanged.