Hairy cell leukemia: absence of natural killer activity and of interleukin 1 release in OKM-1+ spleen hairy cells

Splenic metastasis in hairy cell leukemia

BACKGROUND

Splenic metastasis is uncommon and usually occurs in the setting of widespread visceral metastasis. Splenic metastasis as an initial manifestation of disease and sole site of metastasis has not been reported previously.

METHODS

The authors describe a patient with hairy cell leukemia (HCL) with the unexpected finding of metastatic adenocarcinoma in the spleen. Direct inspection at the time of laparotomy and subsequent radiographic studies did not show a primary or additional metastatic tumor. Eventually, he manifested evidence of pulmonary and hepatic metastases and died with fungal sepsis.

RESULTS

The splenectomy specimen showed HCL and metastatic adenocarcinoma. Immunohistochemical studies showed adenocarcinoma with diffuse cytoplasmic staining for prostate-specific antigen and focally positive results with prostatic acid phosphatase antigen. Postmortem examination 9 months later showed HCL and widespread metastatic adenocarcinoma. No primary tumor was identified, and multiple tissue blocks of the prostate had negative findings for tumor.

CONCLUSIONS

The immunohistologic features of the metastatic adenocarcinoma were interpreted as prostatic in origin. The pattern of isolated metastatic disease in the absence of primary tumor appears to represent another possible atypical disease presentation of prostatic cancer. Hairy cell-induced structural and immunologic alterations within the splenic microenvironment may have contributed to this unique clinical presentation.

Hairy cell leukaemia: observations on natural killer activity in different clinical stages of the disease

Follow-up studies of natural killer (NK) cells, NK activity and antibody dependent cellular cytotoxicity (ADCC) in the course of hairy cell leukaemia (HCL) were carried out in a series of patients affected by the disease. NK activity against K562 targets was found to be high in all the patients with non-symptomatic stable disease. On the other hand, absent or extremely low NK activity was found only in patients with symptomatic progressive disease. NK activity determined in the transitional stages showed values between these two extremes. Antibody dependent cellular cytotoxicity (ADCC) was less closely correlated with the clinical stage than NK activity. Our findings suggest that investigation of in vitro NK cell cytotoxicity might serve as a useful adjunct in determining clinical stage in HCL.

Modulation of immune functions by long-term treatment with recombinant interferon-alpha 2 in a patient with hairy-cell leukemia

Serial in vitro immune function studies of peripheral blood mononuclear cells (PBMC) were carried out during the long-term treatment with recombinant interferon-alpha 2 (IFN-alpha 2) in a patient with hairy-cell leukemia (HCL). Parameters of B- and T-cell functions as well as NK-cell activity were determined. Treatment with IFN-alpha 2 is associated with temporary and long-term depression of some immune functions, but can also normalize immune responses: in vitro-induced immunoglobulin synthesis, which was normal at diagnosis, was inhibited during the first weeks of IFN therapy but subsequently rose to normal levels. Lymphocyte proliferative responses to mitogens and antigens that were markedly reduced pretherapeutically were further depressed by IFN treatment but, with the exception of pokeweed mitogen (PWM)-induced responses, normalized completely by the 15th to 17th week of treatment. Cocultivation of PBMC with monocytes from normal individuals enhanced depressed lymphocyte proliferative responses. NK-cell activity, which was low at diagnosis, did not rise to the normal range during IFN treatment, but rapidly normalized when IFN therapy was stopped. A discussion is presented on the implications of the alteration of immune functions by treatment with IFN.

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.

Generation of procoagulant activity by hairy cells in response to endotoxin and phorbol esters

Several investigators have suggested that hairy cells are neoplastic B lymphocytes. These cells, however, also share some biological properties with mononuclear phagocytes. A property of these cells is the capacity to generate procoagulant activity (PCA) in response to a variety of stimuli. In this study we investigated the PCA of peripheral blood hairy cells in 19 consecutive patients with hairy cell leukaemia (HCL). Monocyte-depleted blood mononuclear cells, tested immediately after isolation, expressed little, if any, activity. However, after exposure to endotoxin, a marked increase in PCA was observed (42.1 +/- 8.7 vs 1.3 +/- 0.2 units/5 X 10(1) hairy cells). A significant correlation was found between the number of lymphocytes/hairy cell and the level of endotoxin-induced PCA suggesting that lymphocytes potentiate the procoagulant response of hairy cells. When stimulated with 12-0-tetradecanoyl-phorbol-13-acetate (TPA), patients' cells produced about 2-8 times more PCA than endotoxin-stimulated cells. The PCA induced by endotoxin and TPA was identified as tissue factor. These findings suggest some further relationship between hairy cells and monocytes.

Lack of natural killer cell activity in hairy cell leukemia patients and partial restoration with interleukin-2

Natural Killer (NK) cell activity was studied in ten hairy cell leukemia (HCL) patients by means of a 4-hour cytotoxicity assay using mononuclear cells isolated from either the spleen or peripheral blood. Identical assays were performed on individuals who were either normal or had nonmalignant hematologic disorders. HCL patients had a significant decrease in NK cell activity at all effector-to-target ratios compared with the control group. Effects of interleukin-2 (IL-2) on NK activity were studied in four patients. After a 3-day in vitro incubation with IL-2, there was a marked increase in NK activity of mononuclear cells obtained from each of these patients. On the basis of the results it can be hypothesized that susceptibility to infections, which are commonly encountered in HCL patients, may be due in part to a low level of NK activity. Based on the apparent augmentation of NK activity in vitro, it might be of interest to initiate a clinical trial with IL-2 in patients with HCL.

A comparison of membrane marker phenotypes in hairy-cell leukemia and phorbol-ester induced B-cll cells using monoclonal antibodies

The neoplastic cells from 14 cases of hairy-cell leukemia were investigated in order to determine their membrane phenotype on the basis of their reactivity with a large panel of B-, T-, myeloid/monocytic- and non-lineage restricted monoclonal antibodies. The data were compared to those from monoclonal antibody studies on phorbol-ester (TPA) induced cells from 10 patients with B-type chronic lymphocytic leukemia. The study has so far revealed further evidence for the B-cell nature of hairy-cells leukemia and demonstrates a developmental link between the two cell types, suggesting that hairy-cells represent a more advanced differentiation stage along the B-cell lineage.

Further evidence for the B-cell nature of hairy cells. A study using immunostaining of splenic tissue with a wide panel of monoclonal antibodies

Phenotypic characterization of neoplastic cells from 5 patients with hairy cell leukemia (HCL) was performed with 29 monoclonal and 6 polyclonal (anti-Ig) antibodies using immunoperoxidase staining of fresh frozen splenic tissue. Monotypic Ig was expressed in 4 cases, one case was non-expressive. Strong staining was obtained in all cases by monoclonal antibodies (MAs) specific for 3 pan-B-lymphocyte antigens (by anti-B 1, To 15, anti-Leu 12). Five other B-cell related antigens detectable with appropriate MAs (BA-1, anti-B2, DAKO-C3 b R, Tü 1, 38.13) were absent in all cases. The stainings with 13 T-cell associated MAs (OKT 3, OKT 4, anti-Leu 3 a, OKT 6, OKT 8, Tü 68, OKT 10, anti-Lyt 2, Tü 71, OKT 11, anti-Lyt 3, Tü 14, Tü 33) were all negative. Stainings with 4 MAs recognizing myelocytic and/or monocytic antigens (OKM 1, anti-Mo 1, anti-Mo 2, 3 C4) were also negative. We included 14 frozen biopsies with B-type chronic lymphatic leukemia (B-CLL) into our immunohistological study in order to establish phenotypic differences between HCL and B-CLL. Five MAs (Tü 1, anti-Lyt 2, Tü 71, BA-1 and anti-B2) gave consistently negative staining in HCL cases but positive staining in most or all B-CLL cases. The study provides significant evidence for the B-cell nature of HCL and also establishes important phenotypic differences between HCL and B-CLL.

Hairy cell leukemia

Hairy cell leukemia is a malignancy with a variable course that can be relatively indolent or rapidly fatal. Alterations in the immune system are responsible for much of the morbidity and mortality from hairy cell leukemia. More than 60% of patients die from infection, and infections are both pyogenic and nonpyogenic. Many patients have transfusion requirements, and bleeding complications can also occur. Treatment strategies for hairy cell leukemia have evolved and are being modified as more is learned about the disease. Splenectomy is the initial treatment when patients become symptomatic, and if the disease progresses after splenectomy, chlorambucil offers good control in many patients. Radiation can be used for local palliation, as when complications such as bulky adenopathy or bone lesions occur. Initial studies using interferon in the treatment of hairy cell leukemia look encouraging, but more investigation is necessary before the role of interferon in treatment of hairy cell leukemia is determined.