The platelet in leukemic reticuloendotheliosis. Functional and morphological evidence of a qualitative disorder

Acute airway obstruction in a child with acute lymphoblastic leukaemia during central venous catheterization

We report the case of a seven-year-old girl with recently diagnosed acute lymphoblastic leukaemia (ALL) who suffered acute airway obstruction during insertion of a central venous catheter under general anaesthesia. The central airway obstruction was due to a mixture of leukaemic cells, blood clot and fibrin. There is discussion about airway obstruction both as a complication of central line insertion and secondary to ALL. The pulmonary complications of ALL, with particular reference to pulmonary haemorrhage, are detailed. The management of blood clot obstructing the central airway is discussed.

Impaired conversion of exogenous arachidonic acid by platelets to thromboxane B2 and correction of that deficiency by interferon-alpha

In the course of an investigation of cyclooxygenase and 12-lipoxygenase activity in platelets of patients with myeloproliferative syndrome receiving treatment with interferon-alpha 2 patients showed unusual results which have not been reported so far. Both patients had thrombocytosis, in one case associated with polycythaemia. In platelets of both patients, a reduced conversion of exogenous 14C arachidonic acid to TXB2 was observed accompanied by a shift in conversion to PGE2 and 12-HETE in one patient and to 12-HETE alone in the other before therapy. These findings were paradoxically associated with evidence of enhanced platelet activation in vivo. Treatment of both patients with interferon-alpha resulted in reversal of the biochemical abnormalities and in clinical remission.

Evolving therapy of hairy cell leukemia

The rationale for antileukemic therapy in hairy cell leukemia is to reduce the significant risk of infection and other potential serious complications. Corticosteroids have limited value; both corticosteroids and chemotherapy are associated with substantial risks of infection. The mainstay of therapy has been splenectomy. Improvement is seen in 50% to 70% of patients with cytopenias; although the impact of splenectomy on survival has not been clearly demonstrated, prolonged hematologic improvement can occur. Splenectomy presumably alleviates the pancytopenic effect of hypersplenism by removing the preferred site of leukemic cell proliferation. Human interferon represents a major advance in management. Favorable results with natural leukocyte alpha interferon have been confirmed by data with biosynthetic (recombinant) alpha interferon. Importantly, the incidence of infection has been clearly shown to decrease, suggesting improved survival in patients with advanced hairy cell leukemia. Many questions regarding interferon therapy remain unanswered, including optimal dose, optimal duration, and maintenance therapy after maximal response. The mechanism of action is unclear, but possibly interferon modulates as yet unidentified lymphokines or growth factors. In vitro evidence suggests a direct antiproliferative effect of type I interferon on hairy cells. Preliminary data suggest that although toxicity issues, including induction of immunodeficiency and renal insufficiency require further clarification, deoxycoformycin, an adenosine deaminase inhibitor, is also highly effective and holds substantial promise as an important therapeutic modality.

Hairy cell leukemia

Hairy cell leukemia is a chronic lymphoproliferative disorder that has been recognized as a separate clinical pathologic entity for the last 25 years. After a decade of discussions about the origin of the neoplastic cell, it has now been well established that hairy cells represent a certain, rather mature stage of B-cell differentiation. Evidence for this has been derived from studies using immunophenotyping with monoclonal and polyclonal antibodies, cytochemistry, and immunoglobulin gene rearrangement. For many years, splenectomy was the only therapy of proven value in hairy cell leukemia. For patients who showed insufficient response to the operation, chemotherapy with low-dose alkylating agents was moderately successful, whereas polychemotherapy often resulted in excessive toxicity. More recently, therapy with alpha-interferon has been shown to be very promising, whereas deoxycoformicin may be an attractive alternative. These new advances in immunology and therapy are reviewed.

Sideroblastic anemia associated wtih hairy cell leukemia

A patient with leukemic reticuloendotheliosis ("hairy cell" leukemia) with sideroblastic anemia and an epinephrine-induced platelet-aggregation abnormality is presented. Immunologic membrane marker studies supported a B-lymphocyte origin of the hairy cells. It is hypothesized that a defect in the pluripotent marrow stem cell may be responsible for the hairy cell leukemia and for the intrinsic abnormalities in erythrocytes and platelets.

Platelet function in hairy-cell leukaemia

A quantitative study of various aspects of platelet function was carried out in eight patients with typical hairy-cell leukaemia (HCL). In at least two patients platelet aggregation was convincingly reduced to more than one aggregating agent (ADP, adrenaline, collagen, thrombin, and ristocetin). Granular storage capacity for {(14)C} 5-HT was reduced in five of the six patients tested. The two patients with definitely abnormal aggregation had the greatest reduction in granular storage pool and the longest bleeding times of those tested but, like the other patients, they did not have a clinical haemostatic defect. It was concluded that a granular storage pool defect (SPD) was at least partly responsible for aggregation abnormalities in HCL since the platelet release reaction in response to thrombin appeared to be normal. All our patients ran a chronic course uncomplicated by any of the factors known to predispose to a platelet SPD acquired in the circulation. Although in the one patient tested before and after splenectomy there was some improvement in platelet aggregation after operation, there was no clear general relationship between defective platelet function and either previous splenectomy or platelet count. Since a direct involvement of the megakaryocytic series in the underlying cell proliferation of HCL seems unlikely, it is concluded that the platelet defect can most reasonably be attributed to the production of abnormal platelets as a result of marrow fibrosis and/or infiltration by hairy cells.

Hairy cell leukemia: an analysis of the chromosomes of 26 patients

We studied the chromosomes from 26 patients with hairy cell leukemia (HCL) to ascertain the frequency and types of consistent chromosomal abnormalities. Samples from 21 patients were obtained from peripheral blood cultures grown 24 and 48 h without phytohemagglutinin, or from bone marrow samples. Two male patients had similar, consistent abnormalities; one patient's karyotype was 46, X, +12; that of the second was 46, X, +C marker. In the latter case, the distal long arm of the C marker most closely resembled chromosome No. 12 from band q14 to q terminal, but the short arm and proximal long arm were of undetermined origin. Both karyotypes lacked the Y chromosome. Nine of the 21 patients had abnormalities in single cells. One patient had, in one sample, a single abnormal cell with an extra No. 3 and an extra No. 12 (48, XY, +3, +12), and in a later sample, a second cell of poor morphology which also could have been trisomic for No. 12. Another patient had one cell with an unusually bright short arm, as well as two cells, with different abnormalities, both involving the short arm of chromosome No. 1. The two patients with consistent chromosome abnormalities had rapidly progressive disease in spite of splenectomy, and their clinical course from the time of diagnosis was relatively short (5 and 7 months, respectively).

Hairy cell leukemia: an unusual lymphoproliferative disease: a study of 24 patients

A laboratory and clinical evaluation of 24 patients with hairy cell leukemia was carried out over a 23-month period. Most patients had splenomegaly without adenopathy or pancyotpenia. Nine of the patients had undergone splenectomy prior to referral; their median WBC count was 6600/mm3. The median WBC count for the 14 patients who had no prior therapy was 3550/mm3, and their median platelet count was 80,500/mm3. Spleen weights ranged from 618 to 3780 g; there appeared to be no relationship between the size of the spleen and the response in the blood counts after splenectomy. Four patients in whom the majority of the WBC were hairy cells underwent splenectomy, which produced no real change in their WBC count; however, there was improvement in the platelet count in three. In contrast, the presence of leukopenia with a low percentage of hairy cells predicted a beneficial response to splenectomy. The study of surface immunoglobulins (SIg) in 16 patients demonstrated that resynthesis had occurred in each case. Phagocytosis of zymosan was studied in 15 patients; in 8 of these, 25% or more of the hair cells were capable of phagocytosis; in 6 others, 0--9%; and in one, 13%. The resynthesis of SIg is a feature usually associated with B-lymphocytes, but the phagocytosis of zymosan is not. Thus, the existence of either a spectrum of functional capabilities of hairy cells or several distinct subtypes is suggested by these data. Platelet aggregation with epinephrine was abnormal in 7 of 14 patients studied but there were no clinically significant bleeding problems. A chromosome abnormality was present in 2 of the 19 patients from whom adequate samples were obtained; the abnormality probably involved chromsome 12 in both patients as well as absent Y and was associated with a rapidly progressive clinical course. The presence of a predominant number of hairy cells with a normal or increased peripheral blood WBC count or of a chromosomal abnormality suggests that splenectomy might not be beneficial as the initial therapy and that chemotherapy should be considered.