Hairy cell leukemia (leukemic reticuloendotheliosis) II. Ultrastructure of the spleen.

Seven surgically removed spleens from patients with hairy cell leukemia and hypersplenism were examined ultrastructurally. In all spleens the pulp cords were diffusely and compactly infiltrated by hairy cells. Numerous hairy cells were also evident in the often distended sinuses. The hairy projections were readily visible in electron micrographs and tended to interdigitate to form syncytium-like aggregates. Compression of hairy cells within the cords flattened the projections against the cell bodies and may account for the surface alterations reported by scanning electron microscopic studies. Controversy over the cytogenesis of hairy cells has not been resolved by ultrastructural studies. Although all seven patients had hypersplenism, the hairy cells showed no evidence of phagocytic activity. However, active phagocytosis by cordal macrophages was observed and there is a probable absolute increase in their number contributing to the splenomegaly. The dense infiltrate of hairy cells causes marked widening of the cords and retards the passage of formed elements of the blood through the red pulp. Prolonged sojourn of these elements in a metabolically unfavorable environment results in cellular damage, increased exposure to cordal macrophages, and premature destruction with the evolution of a hypersplenic syndrome.     

Evidence for an association between hairy cell leukemia and renal cell and colorectal carcinoma.

BACKGROUND. Hairy cell leukemia (HCL) has been associated with several disease states. In this study, a possible association is reported between HCL and renal cell carcinoma (RCC) and colorectal carcinoma (CRC). METHODS. A retrospective study of the case records of 50 patients with HCL in a study of alpha-interferon (alpha-IFN) treatment of HCL. RESULTS. Three of 50 patients with HCL studied had RCC, and 2 of these also had CRC. In addition, two other patients had CRC. The other malignant lesions developed either before or after the diagnosis of HCL. In all patients, the HCL responded to alpha-interferon (alpha-IFN), but in four patients, the second lesion was diagnosed during IFN treatment. CONCLUSIONS. These findings could indicate that IFN does not correct a possible common basic etiologic defect and shows that even early CRC and RCC do not respond to the IFN doses administered. These findings should be considered in future trials of IFN treatment of these diseases. The authors also recommend a reevaluation of the frequency of second malignant lesions in HCL; this may be important particularly with the increased survival in patients with HCL who receive alpha-IFN treatment.     

Myeloid progenitor cells in the peripheral blood of patients with hairy cell leukemia and other "leukemic" lymphoproliferative disorders

We assayed granulocyte-macrophage committed progenitor cells (CFU-GM), erythroid committed progenitor cells (BFU-E) and pluripotent hemopoietic progenitor cells (CFU-MIX) in the peripheral blood of patients with hairy cell leukemia (HCL), acute lymphocytic leukemia (ALL) and chronic lymphocytic leukemia (CLL). In 8 HCL patients retaining their spleens, the number of circulating CFU-GM, BFU-E and CFU-MIX were under the lower limits of normal controls in 6, 6 and 5 cases, respectively, and were in the lower normal ranges in the remaining cases. Six splenectomized HCL patients had generally more circulating progenitor cells than their nonsplenectomized counterparts. In the peripheral blood of 2 patients with ALL and 3 patients with CLL, progenitor cells of all types were markedly increased compared to their respective values in the blood of control subjects. Hairy cells from 2 HCL patients failed to inhibit CFU-GM, BFU-E and CFU-MIX derived colony growth from control peripheral blood mononuclear cells. In 3 HCL patients previously low circulating progenitor cells did not rise 5-7 months after RC-alpha 2-IFN treatment despite normalization of peripheral blood counts. Our results suggest that a reduction of the committed and pluripotent progenitor cell compartment might be at least in part responsible for the pancytopenia in the majority of patients with HCL.     

Heterogeneous somatic hypermutation status confounds the cell of origin in hairy cell leukemia

Hairy cell leukemia (HCL) is thought to arise from a post-germinal center (GC) B-cell, however the exact normal counterpart remains unclear. We performed VH gene analysis of 32 HCL cases, revealing somatically mutated VH genes (<98% homology) in 27 cases and unmutated VH genes in five cases, four of which displayed germline VH genes. Intraclonal heterogeneity was evident in the majority of eight mutated HCLs investigated, although at a lower level compared to GC-derived lymphomas. A novel finding of preferential VH3-30 gene usage was detected (19% of HCLs). Our data confounds the postulated post-GC origin in HCL considering (1) the finding of unmutated HCLs, generally correlating with a pre-GC origin, and (2) the presence of intraclonal variation in mutated HCLs. The latter suggests that the transformed B-cell was frozen when it still had an active mutation process, implying a closer relation to the GC than previously assumed. Furthermore, restricted VH3-30 usage indicates that antigen selection could be a promoting factor in HCL development.     

Restrictions upon Epstein-Barr virus infection of the leukemic cell are demonstrated in patients with hairy cell leukemia

We tested the hypothesis that Epstein-Barr virus (EBV) might actually infect leukemic hairy cells in vivo by examining those cells for the EBV-receptor, EBV nuclear antigen (EBNA) and membrane antigen (MA), for spontaneous transformation and rescue of infectious virus and for presence of EBV genome. EBV-receptors were found on subpopulations of leukemic cells from each of 7 patients with hairy cell leukemia (HCL) tested. MA was present on low numbers (1-5 per cent) of fresh leukemic cells of 7 patients and in some instances occurred with a greater frequency after 3 to 5 days in culture, with or without 12-O-tetradecanoylphorbol-13-acetate. In 11 fresh leukemic cell preparations from 8 HCL patients, no EBNA was demonstrated. However, 2 samples after 4 days in culture expressed low frequencies of EBNA-positive cells. Spontaneous, EBV-positive cell lines were established with a high transformation efficiency from 3 HCL blood samples but not from 8 other specimens. Infectious EBV could be rescued from some hairy leukemic cell preparations by co-cultivation with cord blood lymphocytes. These results demonstrated that leukemic cell populations harbored infectious EBV, that the leukemic cells expressed virus receptors and suggested that a small subpopulation of leukemic cells might become infected in vivo at least transiently and possibly transformed in vitro by EBV. To test for the extent of occult in vivo infection of leukemic cells with EBV, Southern type hybridization studies were performed with a probe for EBV genome (Bam HI W). At a sensitivity level of 0.1 genome per cell, EBV genome was not detected in the leukemic cell populations of 7 patients. We conclude that host defence mechanisms protecting these individuals from EBV also prevent infections of the leukemic cell and/or most hairy leukemic cells are not suitable targets for both infection and transformation.     

Strategy for the treatment of hairy cell leukemia

Both splenectomy and alpha-interferon are efficient treatments for hairy cell leukemia. Since interferon therapy seems to induce remissions of the disease, avoids the risks of surgery, and sustains the spleen, it should be discussed if this therapy may replace splenectomy as primary treatment for this disease. In order to make this decision the biologic relevance of complete remissions in hairy cell leukemia, the reliability of methods to confirm remission, the benefits and risks of both splenectomy and interferon therapy, and some aspects of the pathogenesis of the disease have to be considered. Based on our experimental and clinical results and data from other groups, we conclude that splenectomy should still be recommended as primary therapy in hairy cell leukemia provided that treatment is indicated and the patient is eligible for surgery.     

Clinical aspects of hairy cell leukemia and its modification by splenectomy

From 1972 to 1981 10 patients with hairy cell leukaemia were observed in the Medical University Clinic Cologne, this represents 1.8% of all leukaemias. Typical clinical signs are splenomegaly, no or only slightly enlarged lymph nodes and a moderate hepatomegaly. Almost in all cases an anaemia, thrombocytopenia and neutropenia with lymphocytosis was found, mostly combined as pancytopenia. The pathognomonic tartrate resistant acid phosphatase was found in the hairy cells to a differing amount besides a fibrosis and a lymphatic infiltration of the bone marrow. A normalization of the anaemia, the thrombocytopenia and the neutropenia was reached by splenectomy, but the increased susceptibility to infections could not be affected significantly.     

Surface immunoglobulin, lectin-induced cap formation, and phagocytic function in five patients with the leukemic phase of hairy cell leukemia

Hairy cells from 5 patients with greater than 25% hairy cells in the peripheral blood (4 had greater than 45% hairy cells and white blood cell counts (WBC) greater than 10,000/mm3) were studied for surface immunoglobulin (SIg) presence and distribution by two methods, for lectin-induced cap formation, and for phagocytosis of zymosan. Hairy cells from all 5 cases were found to have distinct monoclonal patterns, 2 Gk, 1 MDk, 1 Dk, and 1 GMDk, as well as cap formation with SIg. All 5 cases showed distinct lectin-induced cap formation in a percentage of cells similar to the percentage of hairy cells, and 2 of the 5 patients had hairy cells which phagocytosed zymosan. These findings contrasted with the malignant cells from 4 patients with CLL, which had monoclonal SIg but no SIg cap formation and no significant percentage of lectin-induced cap formation. Cells from 2 cases of T cell lymphomas had no SIg and no lectin-induced cap formation as did cells from 2 cases of non-lymphocytic leukemia. Hairy cells not only appear to have SIg cap formation similar to some B-lymphocytes, which in some patients also phagocytose zymosan, but also demonstrate strong lectin-induced cap formation.     

Splenectomy for hairy cell leukemia. A clinical review of 63 patients

To further define the role of splenectomy in hairy cell leukemia (HCL), 63 patients who underwent splenectomy for symptomatic cytopenias or splenomegaly associated with HCL were reviewed. Hematologic response to splenectomy was assessed 6 months postsplenectomy by a modification of Catovsky's criteria. The prognostic value of individual clinical findings, hematologic parameters, spleen size, and Jansen stage were examined by the Cox proportional hazards model. Twenty-one patients were excluded from hematologic response analysis for the following reasons: eight patients died between 1 and 6 months after splenectomy was performed; in seven patients hematologic data were unavailable; and six patients did not have significant preoperative cytopenias. Of 42 remaining patients, hematologic response was complete in 67%, partial in 19%, and there was no response in 14%. Overall, 44% of patients had disease progression within 5 years of splenectomy. Thirteen patients had a leukemic progression 1 year after splenectomy was performed. Overall 5-year survival was 61%. There was no operative mortality (30-day), and only 9% of patients had complications. Survival rates after complete, partial, and no response were 62%, 57%, and 75%, respectively at 5 years. Preoperative clinical findings, hematologic data, spleen size, or Jansen stage were not predictive of survival. Despite the absence of identifiable prognostic criteria, splenectomy continues to be advocated for symptomatic cytopenias and splenomegaly of hairy cell leukemia because of its safety and efficacy.     

Evidence for clonal development and stem cell origin of M7 megakaryocytic leukemia

Previous studies have shown that acute nonlymphocytic leukemias are clonal diseases in which there is heterogeneity in the pattern of stem cell differentiative expression. To determine whether M7 megakaryocytic leukemia is a clonal disease and to evaluate the differentiative expression of the cells involved by the leukemia we studied a patient with megakaryocytic leukemia who was heterozygous for the X-chromosome-linked glucose-6-phosphate dehydrogenase (G6PD). The diagnosis of megakaryocytic leukemia was based on results obtained with the immunogold method and ultrastructural studies with the monoclonal anti-Gplla/IIIb antibody, 10E5. Direct testing of blood and marrow mononuclear cells and blood platelets demonstrated only A-type G6PD, whereas skin exhibited both B and A enzymes. The results indicate that the megakaryocytic leukemia in this patient was clonal at the time of study. To determine the differentiative expression of the stem cells, granulocyte/macrophage colony forming units and erythroid burst forming units were cultured and the resultant colonies were tested for G6PD. The results indicate that the stem cells involved by the leukemia exhibited differentiative expression multipotent for the megakaryocytic and granulocytic pathways, but no definitive conclusion could be made regarding the erythroid lineage.     

Acute nonlymphocytic leukemia following gastric adenocarcinoma treated by surgery alone. Evidence for etiologic heterogeneity of "secondary" leukemias

The case of a 36-year-old Hispanic man who developed acute nonlymphocytic leukemia 18 months following gastric adenocarcinoma treated by surgery alone is presented. Cytogenetic analysis of the leukemic cells revealed numerical and structural chromosomal rearrangements including chromosomes 5 and 7 and immunologic characterization of the blasts revealed terminal deoxynucleotidyltransferase positivity with monocytoid features. This report suggests that not all cases of acute nonlymphocytic leukemia following chemotherapy and/or radiotherapy, which characteristically display similar cytogenetic and immunologic features, should be exclusively ascribed to the leukemogenic properties of anticancer treatment.