Aplastic anaemia. Histological investigation of methacrylate embedded bone marrow biopsy specimens; correlation with survival after conventional treatment in 15 adult patients

Predicting response to immunosuppressive therapy and survival in severe aplastic anaemia

Horse anti-thymocyte globulin (h-ATG) and ciclosporin are the initial therapy for most patients with severe aplastic anaemia (SAA), but there is no practical and reliable method to predict response to this treatment. To determine whether pretreatment blood counts discriminate patients with SAA who have a higher likelihood of haematological response at 6 months to immunosuppressive therapy (IST), we conducted a single institution retrospective analysis on 316 SAA patients treated with h-ATG-based IST from 1989 to 2005. In multivariate analysis, younger age, higher baseline absolute reticulocyte count (ARC), and absolute lymphocyte count (ALC) were highly predictive of response at 6 months. Patients with baseline ARC > or = 25 x 10(9)/l and ALC > or = 1 x 10(9)/l had a much greater probability of response at 6 months following IST compared to those with lower ARC and ALC (83% vs. 41%, respectively; P < 0.001). This higher likelihood of response translated to greater rate of 5-year survival in patients in the high ARC/ALC group (92%) compared to those with a low ARC/ALC (53%). In the era of IST, the baseline ARC and ALC together serve as a simple predictor of response following IST, which should guide in risk stratification among patients with SAA.

Clinical significance of plasmacytosis in the day+14 bone marrow of patients with acute myeloid leukaemia undergoing induction chemotherapy

BACKGROUND

The design of chemotherapy-induction regimens for acute myeloid leukaemia (AML) is directed towards the early elimination of bone marrow (BM) leukaemic blast cells (LBCs). Patients with AML after induction show LBC reduction in a hypoplastic BM and also demonstrate a varying number of residual BM plasma cells (PCs).

AIM

To relate PC number to several blood and BM parameters as well as clinical features such as infection and survival.

METHODS

On the 14th day after the start of chemotherapy (D+14) BM samples were examined for residual PCs in 60 adult (>or=15 years) patients undergoing AML-induction chemotherapy, and the proportion of PCs was related to blood and BM parameters including French-American-British (FAB) subtype, other inflammatory cells, antecedent infection, attainment of complete remission and 36-month survival.

RESULTS

Median PC proportion of 11.3% (range 0.1-48.7%) in D+14 BM aspirates and 10.7% (0.6-41%) in trephine biopsies was observed. Their number showed a direct relationship with residual BM lymphocytes (r=0.368; p=0.025). Higher numbers of residual PCs also reflected the presence of infection before diagnosis and coincident with treatment (p=0.039). Although we could not demonstrate an association between PC numbers and 36-month survival, PC numbers were significantly higher in patients with residual leukaemia at D>14 (p=0.007).

CONCLUSION

D+14 BM PC number reflects the effectiveness of induction chemotherapy and the presence of antecedent inflammation or infection.

Bone marrow histopathology of patients with severe aplastic anaemia before treatment and at follow-up

Pretreatment bone marrow biopsies of 63 patients with severe aplastic anaemia (SAA) who were not transplanted and of whom 55 received ATG, were evaluated according to the amount and character of residual haematopoiesis ('genuine' aplasia/intermediate/hypoplastic myelodysplasia (MD], inflammatory infiltrate (Te Velde & Haak, 1977, grade I/II/III), and number of mast cells (normal or slightly increased/increased). Of 61 evaluable biopsies, 47 were 'genuine' aplastic, 11 intermediate and three hypoplastic MD. Inflammatory infiltrates were graded as III in 36/60 evaluable biopsies, as II in 21 and I in three. A moderate to marked increase of mast cells was seen in 19/61. Of grade III patients, 86% had a less than 90 d interval between diagnosis and administration of ATG, versus 50% of grade I/II patients (P less than 0.01). No other correlations with pretreatment characteristics were found. No significant prognostic value for survival or response to ATG of any of these three criteria has been identified. More patients with grade III inflammation tended to show adequate recovery at 4 and 6 months after ATG. Stem cell damage, not identifiable morphologically, and/or impairment of accessory cells might play a major role in eventual outcome of SAA patients. Thirty-five patients are currently alive, median 3.8 years (up to 12.4) after ATG. Follow-up bone marrow aspirates and biopsies of 32 patients were evaluable and none showed normal haematopoiesis. One patient revealed persistent aplasia. Of the remaining 31, haematopoiesis was decreased in 14 and increased in eight. All had dyserythropoiesis, 28 dysplastic myelopoiesis and in 16/29 with evaluable megakaryocytes, dysmegakaryopoiesis was found. Sixteen patients had normo- to hypercellular bone marrows with two dysplastic cell lines (consistent with myelodysplastic syndrome (MDS) according to the FAB-group). The prognostic impact of the dysplastic abnormalities found in these patients needs longer follow-up. Close observation is indicated in view of the previously recognized, albeit uncommon, evolution of SAA to MDS/acute non-lymphocytic leukaemia.

Plastic embedded core biopsy: a complementary approach to bone marrow aspiration for diagnosing acute myeloid leukaemia

Bone marrow aspirates and biopsy specimens were taken at diagnosis from 51 patients with acute myeloid leukaemia (AML). The diagnosis was based on morphological and cytochemical analyses, and the leukaemias were classified by FAB criteria. A considerable difference was observed between the results of bone marrow aspirates and the findings of plastic-embedded bone marrow biopsy specimens, particularly in marrow cellularity, extent of blast cell infiltration, and cell type involved in the leukaemic process. The myelomonocytic cell type seemed to predominate in the sections. In four cases there was considerable marrow infiltration with maturing, but dysplastic, granulocytic cells in the sections, but not in the aspirate smears. Features of potential prognostic importance, such as bone marrow infiltration with inflammatory cells, were easily recognised and quantified in the sections. These results indicate that plastic embedded bone marrow biopsy sections complement the findings of bone marrow aspiration in the diagnosis of AML and may also provide information of independent prognostic importance that cannot be obtained by other means.

Aplastic anaemia--aetiology and clinical features

Acquired aplastic anaemia remains a devastating and frustrating disease from which a proportion of patients still die as a result of failure of support measures. Its pathogenesis remains a mystery.

Does histologic grading of inflammation in bone marrow predict the response of aplastic anaemia patients to antithymocyte globulin therapy?

We tested the hypothesis of teVelde and Haak that the degree of bone marrow inflammation in aplastic anaemia might correlate with an immunological process responsive to immunosuppressive therapy. 120 patients with aplastic anaemia but no suitable marrow donor were treated with horse antithymocyte globulin (ATG) and 53 who had matched sibling donors with bone marrow transplants. Pretreatment bone marrow histology in methacrylate and paraffin specimens was graded by degree of inflammatory infiltrate in a four-tiered system. High grade (II-III) was compared to low (O-I) as a correlate of response to ATG. Complete and partial response to ATG was seen in 50% of patients with high grade marrow and 31% of patients with low grade marrow (P = 0.099). Only one of four patients with grade III inflammation responded significantly to ATG treatment. Median survival following ATG therapy was similar in both groups as well. There was a significantly lower median age in the patients with low grade (24.5 years) versus high grade (37.5 years) inflammation (P = 0.016). Grade also had no prognostic value in the marrow transplant group.

Bone marrow histology in myelodysplastic syndromes. I. Histological findings in myelodysplastic syndromes and comparison with bone marrow smears

Forty bone-marrow trephine biopsies of patients with myelodysplastic syndromes (MDS) were studied and compared with bone marrow smears. It proved possible to make the diagnosis of MDS on the basis of bone-marrow biopsies. Features of abnormal erythropoiesis and myelopoiesis, although different from those observed in smears, were easily detectable. Moreover, obvious advantages of bone-marrow biopsy over bone-marrow smears were found. Firstly, the biopsy in MDS gives an exact assessment of the cellularity; secondly, the presence of reticulin fibres, increased in the majority of the cases, can be evaluated; thirdly, dysmegakaryopoiesis is more easily detected in trephine biopsies than in smears; finally, abnormal behaviour of myeloblasts, clustering centrally in the bone marrow, is frequently observed before the smears show an excess of myeloblasts. The bone-marrow biopsy also has a role in difficult cases, where the diagnosis of MDS can not be established on just bone-marrow smears. The five types of MDS, as described by the FAB group, do not represent recognizable histological entities.

Correlation between in vitro and in vivo response to androgens in patients with aplastic anemia

In an attempt to predict the clinical response to androgens, the effects of added fluoxymesterone (FMT) on the in vitro growth of marrow erythroid progenitors (CFU-E) were examined in 15 patients with aplastic anemia and 6 control subjects with normal marrow morphology. In the control group, the addition of FMT enhanced the growth of CFU-E in vitro, the maximum absolute increase being dependent on the basal number of CFU-E. In 10 out of the 11 aplastic anemia patients who responded to androgens in vivo. FMT enhanced the growth of CFU-E in vitro. In this group, there was a positive correlation between the basal number of CFU-E and the maximum absolute increase of CFU-E induced by FMT. In patients who did not respond to androgens in vivo, all except one showed no increase in the growth of CFU-E in vitro by the addition of FMT. Furthermore, in four out of seven patients examined prior to androgen therapy, the addition of FMT enhanced the in vitro growth of CFU-E. Androgen therapy in vivo resulted in marked hematological improvements in all of these four patients. Two out of the remaining three patients in whom FMT did not enhance the in vitro growh of CFU-E failed to respond in androgen therapy. These results indicate that an in vitro CFU-E culture system to the presence of FMT may be helpful in predicting the response to androgens in vivo in patients with aplastic anemia.

Prediction of survival in adults with acquired Bi- or pancytopenia

In a retrospective study of 44 adults with acquired bi- or pancytopenia without evidence of any causal disorder, the survival curve suggested the existence of a subgroup of short survivors, mainly with aplastic anaemia, with death within 4 months. The initial values of 14 single clinical, blood and bone marrow variables were significantly associated with survival less than 4 months. Stepwise multiple logistic regression analyses identified 2 combinations of variables displaying significant simultaneous associations with short survival: (i) increased % of non-myeloid bone marrow cells and haemorrhagic manifestations initially; (ii) increased % of non-myeloid marrow cells, circulating erythroblasts and no history of any drug exposure. The predictive capacities of a resulting estimate of the probability of short survival and of previously introduced prognostic indices were approximately equal. The frequency of a correct prediction of a survival shorter than 4 months was in the range of 0.71-0.78 and that of longer survival in the range of 0.74-0.94.

Busulphan aplasia in rabbits: a model for human aplastic anaemia

Bone marrow histology plays a crucial role in the clinical diagnosis of aplastic anaemia. The nature of the disease means that few studies are available on the histological changes which occur in the early stages of the development of aplasia. We describe here an animal model which may have some relevance in this respect. Rabbits were chronically exposed to busulphan (BU) to induce aplasia. Sequential histological monitoring of the bone marrow was performed to obtain information about the events preceding full-blown aplasia. There was an early decrease and ultimate disappearance of granulo- and megakaryopoiesis with relative sparing of erythropoiesis which showed severe displasia. Increasing lymphoplasmacytoid infiltrate resembling that seen in human aplasia could be observed in the majority of the animals, together with a decrease of the peripheral lymphocyte number. Lymph nodes and spleen did not show lymphocyte depletion and serum gamma-globulin remained stable. Fibrosis was observed in 50% which is in contrast with human aplasia at diagnosis. In half of the animals there was a rise in MCV, which was not correlated with reticulocytosis or degree of dyserythropoiesis. BU-induced aplasia in rabbits, which resembles long-standing grade II human aplasia in many respects, might be a suitable model for the study of aplastic anaemia due to stem cell defects.

Anti-thymocyte globulin treatment for aplastic anemia

20 patients with severe aplastic anemia were treated with anti-thymocyte globulin (ATG), 6 of them in combination with haplo-identical bone marrow. 7 patients (35%) showed a good clinical response within 6 months; they were off transfusions and had greater than or equal to 0.8 x 10(9)/l neutrophils. ATG had the greatest effect on red-cell production and the least on platelet production. The hematological recovery with ATG could not be predicted from the bone-marrow histology, CFU-c growth, or clinical data. However, patients with strong HLA antibodies seemed to respond more often. The actuarial survival was 55% at 5 years. Under intensive supportive care, even 7 out of 12 non-responders were alive after 1 year. ATG appears to be a useful form of therapy for patients with severe aplastic anemia who are not candidates for bone-marrow transplantation.

Prednisone-responsive aplastic anemia associated with T-lymphocyte proliferation

In some cases, bone marrow aplasia has been thought to result from immunologic abnormalities. Our patient had severe transfusion-dependent aplastic anemia, which responded to treatment with prednisone on two occasions. The exacerbations of aplastic anemia were associated with lymphocytic proliferation which on one occasion had the characteristics of T-cell chronic lymphocytic leukemia. Though he had had mild lymphoproliferation for a number of years, he ultimately died with progressive diffuse lymphoid infiltration of the bone marrow and other organs. The simultaneous occurrence of the T-cell lymphoproliferation and aplastic anemia and their simultaneous response to therapy suggests that this may be a clinical example of T-lymphocyte mediated suppression of erythropoiesis.

Prognosis in acquired aplastic anaemia. A multivariate statistical analysis of 80 cases

Prognostic factors were studied in a series of 80 patients with aplastic anaemia. The most important and easily obtainable individual variables, isolated in a previous univariate statistical analysis, were placed in a linear logistic regression model. A prognostic formula was derived containing the following 4 variables, in decreasing order of significance: (1) reticulocytes, (2) interval from onset of symptoms to first visit, (3) mean red cell volume, and (4) platelets. The prognostic formula permits an estimate of the probability of death within 3 months from the first visit. Its usefulness in several clinical situations, especially those related to bone marrow transplantation, is illustrated.

The value of prognostic indices in aplastic anaemia

In 43 patients with aplastic anaemia we assessed the accuracy of different prognostic systems. Patients dying within 6 months after diagnosis were correctly predicted in 60% of cases with the Lynch-index with a sensitivity of 82%. With the Najean-index 40% of these patients are correctly predicted, this index has a sensitivity of 100%. More accurate are the prognostic criteria proposed by Camitta et al [5]. With these criteria, this rapidly fatal group is correctly predicted in 85% of the patients, indicating that 15% of the patients are incorrectly predicted to have a limited survival. The sensitivity, however, is 100%. The Lohrmann-index, based on reticulocyte count predicts 64% of this group with severe aplasia. None of these prognostic systems do accurately predict long survival. We suggest that the best differentiation between patients with a long-term prognosis (more than 5 years) and patients who die from aplastic anaemia within 5 years, is made by re-evaluating the leucocyte and platelet count 3 months after the initial diagnosis. Decrease in blood counts (over 10%) predicts death from aplastic anaemia within 5 years correctly in all patients; stable or increased blood counts predict long survival in 75% of the patients.

111Indium-chloride bone marrow scintigraphy in aplastic anaemia

Bone marrow scintigraphy, using 111Indium-chloride, was performed in 24 patients with acquired aplastic anaemia to investigate: (1) a possible relationship between bone marrow scintigraphy and peripheral blood cell values, (2) a possible relationship between scintigraphy and histology of the bone marrow and (3) the ability to distinguish various aplastic anaemia subtypes with bone marrow scintigraphy. For this purpose a semi-quantitative scoring of scintigraphic results was used. Only a weak correlation was found between the radionuclide studies and blood counts. It appeared that an abnormal 111In-scintigraphic activity in the pelvis was related to an abnormal quality and quantity of haematopoietic tissue. To study a correlation with histological subtype grading, the patients were grouped in 4 categories based on clinical-histological results. Thus it could be demonstrated that the presence of 111In-activity in long bones ('scintigraphic extension') is an important parameter in distinguishing patients who are believed to suffer from a primary stem-cell defect, from patients who may suffer from an auto-aggressive disorder.

Environmental factors in haemopoietic failure in humans

Aplastic anaemia can be defined as pancytopenia in the presence of a hypoplastic bone marrow and in the absence of leukaemia or malignant infiltration. Most cases have been attributed to an intrinsic defect in the pluripotential haemopoietic stem cell; however, stem cell suppression or a defect in the marrow environment would also produce the symptoms of aplasia. In vitro culture systems have been used to explore these possibilities and have provided evidence that the syndrome known as aplastic anaemia includes several distinct disease processes. These include primary failure of the haemopoietic stem cell and the suppression of stem cell function by cellular, humoral or other environmental factors. This heterogeneity provides the background for attempting to treat the disease by bone marrow transplantation, immunosuppression or stimulation of haemopoiesis.

Aplastic anemia: recent advances in pathogenesis and treatment

Successful bone marrow transplantation and bone marrow culturing techniques have generated a large body of research into the pathogenesis and treatment of aplastic anemia. Most prominent has been the emphasis on autoimmune mechanisms. Several etiologic types and diagnostic criteria are discussed, the evidence supporting immune and other mechanisms of pathogenesis is examined, and results of current therapeutic trials are addressed.

Prognostic factors in acquired aplastic anemia. A study of 352 cases

The prognostic factors of short- and long-term survival have been studied in 352 patients with aplastic anemia of all grades of severity. This group was homogeneous with regard to the clinical and laboratory survey, and the treatment used [high-dose androgen therapy]. The "hierarchy" of the individual prognostic parameters has been established: current severe infection, granulocyte count, percentage of the nonmyeloid cells on the bone marrow slides, platelet count, reticulocyte count, 59Fe utilization, and stromal disorganization on the bone marrow biopsy specimen. As these parameters are interrelated, a multiparametric analysis enables us to define groups of patients with different short-term evolution and to derive a prognostic index from these data. The use of such an index, however, allows a correct prediction in only 73 per cent of the cases, better in the milder than in the more severe cases. It is possible that the short-term evolutive tendency (improvement or worsening during the first six weeks of therapy) may contribute supplementary information useful for prognosis and the choice of treatment. After the first three months critical period, the mortality rate no longer depends on the initial severity of the disease but exclusively on the clinical and hematologic improvement. Thus, comparing the hematologic data obtained initially and after three months of androgen therapy allows us to correctly predict the long-term evolution.

Clinical course in 28 unselected patients with aplastic anaemia treated with anabolic steroids

Twenty-eight unselected patients with histologically proven aplastic anaemia were electively treated with anabolic steroids (75-150 mg orally q.d.) Additional supportive treatment with blood cell components and antibiotics was given if indicated. Response to therapy was defined as favourable if after 3 months of anabolic therapy overt bleeding tendency had disappeared, there was no need for transfusion therapy, a spontaneous increase of haemoglobin had occurred of greater than 3 g/dl above the initial level, and a platelet rise of twofold the initial count (up to at least greater than 30 x 10(9) /L) had occurred. Of 22 patients evaluable for the results of long-term (greater than 3 months) anabolic treatment, six showed a partial response and eleven responded favourably. These 11 are all alive at the end of the study. Five of these patients proved to be anabolic steroid-dependent. The 50% actuarial survival is approximately 4 years after diagnosis, which compares favourably with the best published results from bone marrow transplantation for aplastic anaemia. It is concluded that anabolic therapy in aplastic anaemia should be tried for 2-3 months before the bone marrow transplantation or immunosuppressive therapy is taken into consideration.

Severe aplastic anaemia with complete autologous marrow reconstitution following treatment with antithymocyte globulin. Report of a case and review of the literature

In a patient with end-stage acquired aplastic anaemia, unsuccessful treatment with splenectomy, prednisone, pyridoxine and anabolic steroid was followed by administration of antithymocyte globulin (ATG). This therapy soon led to a gradual improvement and after 12 months, complete remission was obtained. The possible mechanism of action of ATG and the general principles of treatment are discussed.