The significance of lysozyme estimations in acute myeloid and chronic monocytic leukaemia

Intracytoplasmic Lysozyme in Malignant Hematologic Disorders: An Immunoperoxidase Study

Intracytoplasmic lysozynie was studied by the peroxidase antiperoxidase (PAP) and protein A-peroxidase methods in 130 cases of various myeloproliferative and lymphoproliferative disorders and 21 lymph nodes and bone marrow metastases from solid primary tumors. This marker, which can be identified in formalin or Zenker-fixed tissues, as well as in peripheral blood and bone marrow smears, proved useful to distinguish malignant myeloid and histiocytic tumors from malignant lymphoid and undifferentiated epithelial metastases. The diagnostic application of these findings are discussed.

Quantitative proteomics reveals a role for epigenetic reprogramming during human monocyte differentiation

The differentiation of monocytes into macrophages and dendritic cells involves mechanisms for activation of the innate immune system in response to inflammatory stimuli, such as pathogen infection and environmental cues. Epigenetic reprogramming is thought to play an important role during monocyte differentiation. Complementary to cell surface markers, the characterization of monocytic cell lineages by mass spectrometry based protein/histone expression profiling opens a new avenue for studying immune cell differentiation. Here, we report the application of mass spectrometry and bioinformatics to identify changes in human monocytes during their differentiation into macrophages and dendritic cells. Our data show that linker histone H1 proteins are significantly down-regulated during monocyte differentiation. Although highly enriched H3K9-methyl/S10-phos/K14-acetyl tri-modification forms of histone H3 were identified in monocytes and macrophages, they were dramatically reduced in dendritic cells. In contrast, histone H4 K16 acetylation was found to be markedly higher in dendritic cells than in monocytes and macrophages. We also found that global hyperacetylation generated by the nonspecific histone deacetylase HDAC inhibitor Apicidin induces monocyte differentiation. Together, our data suggest that specific regulation of inter- and intra-histone modifications including H3 K9 methylation, H3 S10 phosphorylation, H3 K14 acetylation, and H4 K16 acetylation must occur in concert with chromatin remodeling by linker histones for cell cycle progression and differentiation of human myeloid cells into macrophages and dendritic cells.

Serum Lysozyme (Muramidase) Levels in Intra-Abdominal Abscesses: An Experimental Study

The role of serum lysozyme in the presence of intra-abdominal sepsis was studied to act as an adjunct to various other modalities used for diagnosing intra-abdominal abscesses. Lysozyme (muramidase) is a bacteriolytic enzyme located within phagocytic cells including leukocytes. We measured serum concentrations of lysozyme by a standard turbidimetric method on three groups of murine models. One group underwent caecal ligation and puncture (CLP), the second group underwent a sham operation, and the third group was used as controls. In mice with intra-abdominal abscesses secondary to caecal ligation and perforation (n = 30), the serum lysozyme levels were increased compared to the sham-operated mice (n = 30) and controls (n = 30) (p = <0.001). In this study, serum lysozyme levels have a high sensitivity and specificity related to the presence of an intra-abdominal abscess in mice. Clinical studies are required to demonstrate its role in humans.

Polycythemia vera megakaryocytes store and release lysozyme to a higher extent than megakaryocytes in secondary polycythemia (polyglobuly)

Lysozyme, a myelomonocytic marker not only exerts bacteriolytic, but also immunomodulatoric properties and was found to bind to the glycosaminoglycan serglycin, an important constituent of the extracellular matrix (ECM). Pathological serum lysozyme levels were described in chronic myeloproliferative disorders (CMPDs) and other hematological conditions. In this context it is remarkable that in polycythemia rubra vera (PV), characterized by a proliferation particularly of the megakaryo- and erythropoiesis, serum lysozyme levels behave independently of the numbers of myelomonocytic cells in peripheral blood. To elucidate whether megakaryopoiesis might be the source of the increased serum lysozyme, we performed an experimental study on isolated and enriched megakaryocytes derived from bone marrow of patients with PV. Findings were compared to a group of patients with reactive (smoker's) polyglobuly (PG). In confirmation of previous results, quantification of serum lysozyme levels showed a slight elevation in the cohort of PV patients which was not correlated with the leukocyte count. Applying an immunohistochemical assay we were able to demonstrate intracytoplasmic lysozyme storage in megakaryocytes. Moreover, performing the reverse hemolytic plaque assay (RHPA), a technique which enables detection of secreted proteins at the single cell level, we found that 54% of the PV, but only 3% of the PG megakaryocytes spontaneously secreted lysozyme. After rhIL-3 treatment the secretion of lysozyme remained unchanged in PV but increased to 14% in PG. These findings suggest that the extent of megakaryocytic lysozyme secretion might discriminate PV from reactive conditions. Although a direct involvement of lysozyme in the regulation of aberrant megakaryopoiesis in PV is not likely, the results of the present study point to the possibility that lysozyme could be involved in the interactions of PV megakaryocytes with ECM. Moreover, the response to rhIL-3 significantly discriminates PV megakaryocytes from megakaryocytes of the PG group.

Distinct lysozyme content in different subtypes of acute myeloid leukaemic cells: an ultrastructural immunogold study

Using an ultrastructural immunogold method, we performed a quantitative study on cellular lysozyme (LZ) content in young normal bone marrow cells and in 14 cases of acute myeloid leukaemia (AML) of the M2, M3, M4 and M5 types. In five cases of M2 we found significantly lower LZ content than in normal promyelocytes and than in nine cases of M3, M4 and M5. In M3, M4 and M5 cells a very high LZ content was observed whereas the serum LZ activity was high in M4 and M5 and normal in M3. The intragranular LZ content was especially high in M5 and in most granules of M4 cells. The immunogold reaction (IGR) for LZ was also performed in cells previously reacted for myeloperoxidase (MPO). In M2 the granules showed definite positive MPO reactivity and low LZ density (granulocytic pattern), whereas in M5 we found high granular LZ content and weak or almost negative MPO activity (monocytic pattern). In M4 we found 'granulocytic' and 'monocytic' type of granules in the same cell. The IGR for LZ performed in post-embedded M5 cells which were previously subjected to phagocytosis of latex particles, showed granules that had moved toward the phagosome, releasing LZ without degranulation. The above findings and those showing normal serum LZ in M3 despite their high cellular LZ content, definitely indicate that only leukaemic M4 and M5 cells secrete LZ into their environment, explaining the high serum LZ observed in those leukaemias.

Acute myelogenous leukemia with leukemia cutis. Eighteen cases seen between 1969 and 1986

Leukemia cutis was documented by biopsy in 18 of 877 patients (2%) with acute myelogenous leukemia (AML) seen at Roswell Park Memorial Institute (Buffalo, NY) between 1969 and 1986. French-American-British (FAB) types included four M2, one M3, ten M4, and three M5. Lysozyme was more consistently detectable in skin sections in our cases than Leu-M1, alpha-1-antitrypsin, alpha-1-antichymotrypsin, or chloroacetate esterase activity. Additional extramedullary sites of involvement were present in 16 patients, including meningeal leukemia in six. Two patients had leukemia cutis preceding bone marrow leukemia. Skin was the initial site of relapse in 11 patients, without marrow relapse, occurring as late as 5.5 years after diagnosis. Most patients in this retrospective series were treated with radiation therapy and/or palliative chemotherapy, and did poorly, with prompt bone marrow relapses and serial skin relapses. Long-term disease-free survival was achieved in the one patient whose skin relapse was treated with whole-body electron-beam radiation therapy in conjunction with reinduction and consolidation chemotherapy. Severe skin toxicity was caused by administration of Adriamycin (doxorubicin) 12 days after electron-beam irradiation in one patient, but was not seen when cytosine arabinoside was administered in doses up to 3 g/m2 in conjunction with radiation therapy. This retrospective review suggests that optimal management of AML involving skin might include whole-body electron-beam irradiation in conjunction with induction or reinduction chemotherapy without anthracyclines, followed by consolidation chemotherapy. Additionally, there should be ongoing surveillance for and treatment of extramedullary disease at other sites, including the meninges.

The mechanism of cadmium-induced lysozyme enhancement in rabbit kidney

The effect of cadmium on the renal lysozyme level was examined by injecting male albino rabbits subcutaneously with 1 mg cadmium/kg body weight three times a week for 1 or 3 months. The lysozyme level in the renal brush border membrane of the cadmium-treated animals was elevated ten-fold. The lysozyme activity in the liver and small intestine tissue homogenates of rabbits was elevated by a 1-month treatment with cadmium, markedly elevated in the kidney, but markedly reduced in the spleen and lungs. Exposure to cadmium for 3 months produced an essentially similar effect on the enzyme level in the tissue, except for the lungs in which the lysozyme level returned to the preinjection level. This marked increase in the lysozyme level in the kidney of cadmium-treated rabbits was confirmed by an indirect immunofluorescent antibody technique. In control animals, intracellular distribution of the enzyme was selectively distributed to only a small number of proximal tubules, with none distributed in the medulla or glomerulus. However, after expose to cadmium, the renal tubules showed strongly positive lysozyme staining. In addition to an increase in intensity of the specific fluorescence, this enzyme was widely distributed not only in the proximal convoluted portion, but also in the straight portion of the proximal tubules, which essentially showed no enzyme activity under normal conditions. The enzyme in these cells was evenly distributed throughout the cytoplasm. The plasma lysozyme level increased immediately after the administration of cadmium, and detectable amounts of the enzyme began to appear in urine from the 3rd week after the first injection, with a 1-week lag after the maximum level of lysozyme in the plasma. This high level of plasma lysozyme, varied two-to four-fold over the control, and lysozymuria continued throughout the experiment. The concentration of cadmium in the renal cortex was 141 micrograms/g wet tissue at 1 month, and 208 micrograms at 3 months. In conclusion, the cadmium-induced enhancement of the lysozyme level in the renal cortex may be due primarily to the elevation of the lysozyme level in plasma by cadmium. The enzymatic high net positive charge, characteristic of lysozyme, may contribute greatly to this mechanism. In addition, the excretion of a large amount of lysozyme into the urine observed in a later stage may be due to the concomitant occurrence of leakage from the destroyed tubular cells and reduced tubular reabsorption of filtered enzyme, whereas lysozymuria at an early stage may be solely due to excess amounts of plasma lysozyme.

Beta 2-microglobulin, lysozyme and lactoferrin in cerebrospinal fluid in patients with lymphoma or leukaemia: relationship to CNS involvement and the effect of prophylactic intrathecal treatment with methotrexate

Central nervous system (CNS) involvement in patients with leukaemia or lymphoma presents a diagnostic problem. This study was conducted to test whether combined measurements of various cellular markers such as beta 2-microglobulin (beta 2m), lactoferrin (LF) and lysozyme (LYS) in the cerebrospinal fluid (CSF) might aid in the diagnosis of CNS involvement in such patients. Forty-two patients were studied. Sixteen were considered to have CNS involvement and 26 showed no signs of such involvement. In the group with symptoms or signs of CNS involvement, nine patients out of 12 had increased total protein in CSF, 14 of 14 increased beta 2m, 14 of 16 increased LYS and five of 15 increased LF. In patients without CNS involvement total protein was increased in four of 25, beta 2m in three of 21, LYS in four of 28 and LF in one of 28 patients. The differences were statistically significant (P less than 0.01, P less than 0.001, P less than 0.001 and P less than 0.05, respectively). Prophylactic intrathecal methotrexate treatment in patients with acute lymphoblastic leukaemia caused an increase in the CSF of beta 2m, LYS and LF but not of total protein, which may reflect a drug-induced inflammatory reaction in the CNS. We conclude that combined measurements of the three cell markers add to our understanding of the cellular reaction to malignant cells in the CNS in leukaemia and lymphoma and may be valuable supplements in the diagnosis of this CNS involvement.

Interleukin-1 producing ability of leukaemia cells and its relationship to morphological diagnosis

Interleukin-1 (IL-1) is a low molecular weight polypeptide produced by monocyte-macrophage lineage cells. IL-1 production by primary-cultured leukaemic cells of several FAB subtypes was estimated and compared with in vitro and in vivo lysozyme production. The results indicate that IL-1 production by monocytic leukaemia cells (M4 and M5) is significantly higher than that of myelocytic leukaemia cells (M1, M2 and M3). On the other hand, the serum lysozyme level was not correlated with the FAB subtypes and in vitro lysozyme production by monocytic leukaemia cells was higher than that of myelocytic leukaemia cells, but the M2 subtype was indistinguishable from monocytic leukaemia cells solely on the basis of lysozyme production. We concluded that measurement of IL-1 production by leukaemic cells, as a marker of monocytic leukaemias, was convenient and reliable, and might be useful for the diagnosis of morphologically or cytochemically atypical cases.

Urinary trehalase as an early indicator of cadmium-induced renal tubular damage in rabbit

The significance of urinary trehalase as a possible early indicator of renal disorder was examined using Cd-treated rabbits, which received 1 mg/kg Cd thrice weekly for 3 months subcutaneously. The results showed that urinary trehalase increased significantly from 1 week after treatment, earlier than LAP, ALP, proteinuria and glucosuria, with no changes in plasma trehalase level. A marked decrease in trehalase activity in renal brush border membranes prepared from Cd-treated rabbits was observed. It was also confirmed by immunohistological techniques that Cd treatment resulted in a marked decrease in specific fluorescence compared with controls. Ouchterlony double diffusion analysis demonstrated that urine and renal brush border extracts formed precipitation lines against anti-renal trehalase IgG, indicating that urinary trehalase and renal trehalase had the same antigenicity. Therefore, the facts presented here would suggest that urinary trehalase originated from the renal brush border, indicating its superiority as a diagnostic tool over other indicative indicating its superiority as a diagnostic tool over other indicative enzymes like LAP and ALP in detecting injury to renal proximal tubular cells in the early stage.

A rapid and sensitive non-competitive avidin-biotin immuno-enzymatic assay for lysozyme

A non-competitive avidin-biotin immuno-enzymatic assay (NABA) for lysozyme is described. The assay was found to be more sensitive than a competitive assay with biotinylated lysozyme. The lower detection limit of NABA was 0.1 ng lysozyme/ml compared to 1 ng/ml for the competitive assay. The intra-assay and inter-assay coefficients of variation for NABA were 5.9 and 9.1%, respectively. The total time for NABA can be decreased (to less than 1 h) without influencing the detection limit or the analytical range. Serum lysozyme levels measured by NABA and the enzymatic assay in 32 samples showed a correlation coefficient of r = 0.97.

The distribution of lysozyme, alpha-1-antitrypsin, and alpha-1-antichymotrypsin in normal hematopoietic cells and in myeloid leukemias: an immunoperoxidase study on cytocentrifuge preparations, smears, and paraffin sections

Blood and bone marrow samples from 20 individuals with reactive conditions and 26 cases of acute and chronic myeloid leukemias were tested for the presence of lysozyme, alpha-1-antitrypsin (alpha-1-AT), and alpha-1-antichymotrypsin (alpha-1-ACT). We compared the reactivity of samples in smears, cytocentrifuge preparations, and paraffin sections. Lysozyme, alpha-1-antitrypsin, and alpha-1-antichymotrypsin were found only in polymorphonuclear leukocytes and monocytes and their precursors. Lymphocytes, E-rosetting cells, Con A-activated lymphocytes, natural killer (NK) cells, red blood cells, erythroblasts, and megakaryocytes were consistently negative. Leukemic myeloblasts showed definite reactivity for both alpha-1-antitrypsin and alpha-1-ACT, but not for lysozyme. By contrast, lysozyme was present in poorly differentiated leukemic monoblasts, while alpha-1-antitrypsin and alpha-1-antichymotrypsin showed only weak reactivity. More mature myeloid and moncytic cells showed positive staining for all three antigens tested with differences in staining distribution and intensity. In four cases of chronic myeloid leukemia (CML), circulating mature polymorphonuclear leukocytes were deficient in both lysozymne and alpha-1-antitrypsin. The use of lysozyme, alpha-1-antitrypsin, and alpha-1-antichymotrypsin identifies normal and leukemic cells of the myeloid-monocytic series at all stages of maturation and is applicable to a variety of sample preparations.

Control of lysozyme gene expression in differentiating HL-60 cells

We have investigated the control of lysozyme gene expression in HL-60 cells induced to differentiate into macrophage-like cells with phorbol myristate acetate (PMA). Differentiation, as evidenced by cellular adherence, and morphological changes corresponded temporally to an increase in nonspecific esterase activity. The lysozyme concentration in the medium of uninduced HL-60 cells was 10 micrograms/10(7) cells, increasing to a maximum of 46 micrograms/10(7) cells after 48 h incubation with PMA (16 nM). At 72 h the lysozyme concentration decreased to 16 micrograms/10(7) cells. Intracellular lysozyme activity remained constant throughout differentiation. If HL-60 cells were exposed to PMA for 24 h, washed, then maintained in normal medium, they differentiated normally, confirming their irreversible commitment to differentiate. The increase in lysozyme secretion by these cells, however, is markedly blunted suggesting that continued PMA treatment of differentiated cells is required for their secretion of lysozyme. There is no change in the rate of extracellular degradation of lysozyme during differentiation. The level of lysozyme mRNA does not correlate directly with the amount of lysozyme secreted into the medium. Hybridization of uninduced HL-60 cell RNA with a chicken lysozyme cDNA probe demonstrates moderate hybridization. There is a modest (five-fold) increase in lysozyme mRNA between 0 and 36 h of exposure to PMA, corresponding to the burst of lysozyme secretion by these cells. The lysozyme mRNA decreases to a level which is lower than the original baseline by 72 h, when the cells are still secreting substantial amounts of lysozyme. These data suggest that both transcriptional and post-transcriptional controls are operative in the control of lysozyme gene expression during the differentiation of HL-60 cells. They also imply that lysozyme secretion is not a necessary component in the macrophage-monocyte differentiation of these cells.

Plasma and intracellular levels of lactate dehydrogenase, phosphohexose isomerase and lysozyme activity in acute leukemia

Plasma and intracellular levels of lactate dehydrogenase (LDH), phosphohexose isomerase (PHI) and lysozyme activities were investigated in 20 patients with acute myelocytic leukemia (AML), 18 patients with acute lymphatic leukemia (ALL) and 10 patients with chronic myelocytic leukemia in blast transformation (CML/BT). Though the plasma levels of LDH and PHI in all patients with acute leukemia were elevated as compared to control persons there was no distinctive pattern which could be of use in the classification of acute leukemia. On the other hand the intracellular levels of these enzymes could be of value in classifying acute leukemia. The leukemic lymphoblasts were characterized by low levels of PHI and lysozyme as compared to leukemic myeloblasts or to normal lymphocytes (p less than 0.01). The LDH/PHI ratio is also significantly higher in leukemic lymphoblasts than in leukemic myeloblasts or in normal lymphocytes (p always less than 0.01). These characteristics might also be made use of in identifying the blasts of CML/BT als "lymphoid" or "myeloid" in corresponding cases.

Urinary 6-hydroxymethylpterin levels accurately monitor response to chemotherapy in acute myeloblastic leukemia

In our earlier study it was shown that patients with various types of cancer excrete three- to 20-fold higher levels of urinary 6-hydroxymethylpterin as compared to patients with nonmalignant diseases or normal volunteers. In the present study urinary 6-hydroxymethylpterin levels have been measured as an index of disease status in acute myeloblastic leukemic patients on antileukemic drugs. The daily excretory pterin levels and the values of respective blast counts have been graphically presented for four cases with the chemotherapeutic regimens. Remission of the disease was marked by a rapid drop in the urinary 6-hydroxymethylpterin levels and correlated very well with the percentage of blasts. In another study the percentage of blasts and the urinary 6-hydroxymethylpterin were determined simultaneously in four patients undergoing chemotherapy. The data conclusively show that the simple noninvasive determination of urinary 6-hydroxymethylpterin levels accurately and rapidly reflects the status of the disease under treatment and could conveniently be employed as a suitable index for monitoring the effect of chemotherapy as well as the condition of the residual extramedullary leukemic infiltration.

Macrophage-histiocyte lysozyme activity in relation to the clinical presentation of Hodgkin's disease. An immunohistochemical study

The clinical presentation of 71 untreated patients with Hodgkin's disease was studied in relation to immunohistochemically demonstrable lysozyme in the lymph node biopsy material. Sixty-one patients (86%) showed a positive staining reaction of varying degree, while ten (14%) showed no demonstrable lysozyme. The clinical features of lysozyme-positive patients differed markedly from those of lysozyme-negative patients. Stain-positive patients were younger (29 vs. 46), were more often in clinical Stage I or II disease (69% vs. 10%, P less than 0.001), and less frequently had constitutional symptoms (34% vs. 70%, P less than 0.02). Moreover, within the stain-positive group, patients who had the most intense staining reaction (mottling pattern) also had the most favorable clinical and histopathologic features at the time of diagnosis. The observations suggest that in Hodgkin's disease the lysozyme secretory activity of macrophage-histiocytes may be an important element of host resistance to neoplasia and that a depression of this secretory activity corresponds with disseminated disease.

Occurrence and patterns of muramidase containing cells in Hodgkin's disease, non-Hodgkin's lymphomas, and reactive hyperplasia

The occurrence and pattern of cytoplasmic muramidase containing histiocytes were studied by the unlabeled antibody peroxidase-antiperoxidase method in biopsy material from patients with Hodgkin's disease, non-Hodgkin's lymphomas, and reactive hyperplasia. The majority of lymph nodes from patients with Hodgkin's disease, nodular lymphoma, and reactive hyperplasia gave positive staining reactions when tested in this manner. Differences in the staining pattern were observed for the different conditions studied. In general, stain positive cells occurred in one of the following four patterns: nodular, dispersed, aggregating without background stain, or aggregating with background stain (mottling pattern). The nodular and aggregating without background stain patterns were not specific and were seen in various conditions. The dispersed pattern, however, was observed only in some cases of non-Hodgkin's diffuse lymphomas, suggesting a subgroup of tumors characterized by active participation of reactive histiocytes. The mottling pattern was virtually limited to Hodgkin's disease. Since the mottling pattern appeared to be produced by virtue of a large amount of extracellular muramidase, the elevation of the serum muramidase level in Hodgkin's disease may be related to enzymatically active secretory histiocytes. Moreover, the mottling staining pattern was observed frequently in the lymphocytic predominance and nodular sclerosis type of Hodgkin's disease, but relatively infrequently in the mixed cellularity or lymphocytic depletion types, suggesting that the variation in histiocytic activity may be related to the course of the disease. The decreased staining reaction observed in the latter two categories could not be accounted for by a decrease in the numbers of histiocytic cells in hematoxylin and eosin stained sections, suggesting that release or synthesis may be defective in those unfavorable types of Hodgkin's disease.

A noninvasive technique for monitoring response to chemotherapy in human acute leukemia

To see whether urine enzyme activities could be used as an index in evaluating the disease status of leukemia patients, we examined the activities of four enzymes: arylsulfatases A(AS-A) and B(AS-B), alkaline phosphatase (AP), and lactate dehydrogenase (LDH). AP and LDH showed no consistent patterns. The activities of AS-A and AS-B correlated well with the patient's clinical status, increasing during progression of disease and decreasing toward normal activities during responses to therapy, as judged from bone marrow cellularity and differential. Among 23 untreated patients with a histologic diagnosis of acute leukemia we found increased activities of the urine enzymes in these proportions: AS-A in 23 patients (100%), AS-B in 22 (95.7%), AP in 7 (30.4%), and LDH in 10 (43.5%). Five patients in remission from acute leukemia had normal activities for all four enzymes. In one patient in remission for more than one year, a rise in urinary arylsulfatase activity preceded observable bone marrow relapse by 4 months. Unlike that of serum of urine lysozyme and serum copper, the determination of urine arylsulfatase activities appears to be a consistent, useful indicator of response to antileukemic therapy. In contrast to the determination of polyamines, the quantitation of arylsulfatase activity is achieved with greater ease and with instrumentation available in most clinical laboratories.

New aspects of preleukemic disorders

Preleukemic disorders are a controversial group of panmyelopathic disturbances that often precede the emergence of acute myeloblastic or myelomonocytic leukemia. In most instances, these preleukemic disorders are characterized by slowly developing myeloblastosis of the bone marrow. They include preleukemia, primary acquired panmyelopathy with myeloblastosis or smouldering acute leukemia, erythroleukemia, and subacute myelomonocytic leukemia. Sometimes, transitions between these various preleukemic disorders may be observed in a single individual. Abnormalities in cellular differentiation are expressed in cytochemical aberrations and in elaboration of colony forming units by marrow cells of patients with preleukemic disorders. Cytogenic and cellular kinetic abnormalities link preleukemic disorders closely to acute myeloblastic or myelomonocytic leukemia, although in many patients with preleukemic disorders, conversion to acute leukemia is not observed or perhaps not recognized. Understanding pathogenetic and pathophysiological aspects of preleukemic disorders may shed light on aspects of cellular proliferation and cellular differentiation in the acute leukemias.

[Studies of lysozyme activity in serum, urine and blood smears from patients with haematological diseases]

Lysozyme activity was studied in blood smears, serum, and urine of patients suffering from leukaemia or other haematological diseases. Increased enzyme activity was found in myelocytic, myelomonocytic and monocytic leukaemia and equally in secondary granulocytosis and polycythaemia vera. Reduced rates were found in lymphocytie leukaemia, malignant lymphoma with bone marrow involvement, and myelophthisic conditions. A rise in urinary lysozyme occurred when the serum level exceeded 50 microgram/ml. Abundant activities were found in myelomonocytic and monocytic leukaemias. Using the bacteriolytic method in blood smears, no enzyme activity was demonstrated in cells of acute or chronic lymphocytic leukaemia, in monocytic leukaemia however, almost all cells show strong reaction. In acute myelocytic or myelomonocytic leukaemia, the portion of positive cells changes from case to case depending on the degree of cell differentiation and maturation. In chronic myelocytic leukaemia there was no difference as compared to enzyme activity of myelocytes in bone marrow of control cases. Thus the bacteriolytic demonstration of lysozyme in blood smears may additionally contribute to distinction of different types of blastic leukaemias, and serum lysozyme also may allow more reliable insight into granulocytic and monocytic myelopoiesis than morphologic studies of blood or bone marrow smears can do, e.g. in agranulocytosis and pancytopenia.

Prognostic significance of serum lysozyme in adult acute myelogenous leukaemia

Pre-treatment sera from 88 adult patients with acute myelogenous leukaemia have been assayed for their lysozyme content. All 19 patients who presented with a serum-lysozyme level below 15 mug/ml failed to acheive haematological remission from intensive chemotherapy. Serum-lysozyme levels above 85 mug/ml were found in 10 patients, all of whom went into remission. Remissions in this group were, however, shortlived. Of the 59 patients with lysozyme levels between 15 and 85 mug/ml, 39 achieved haematological remission and 12 survived longer than 60 weeks. These findings suggest that estimation of serum-lysozyme may help to identify those patients who are unlikely to respond to the intensive-chemotherapy protocols currently advocated and who could therefore be spared exposure to them.

A method for automatic recording of serum lysozyme activity with the fragiligraph

A quick and simple method for the estimation of lysozyme activity using the Fragiligraph, was described. Diminution of turbidity in a suspension of Micrococcus lysodeikticus produced by the addition of standard lysozyme (hen egg white) or serum sample, was continuously recorded for 5 min by the Fragiligraph. The normal mean serum lysozyme activity value obtained by this method is 6,80 mug/ml +/- 1.85.

Folic acid binding protein in acute myeloid leukaemia

Folic acid binding protein was estimated in the serum of 94 control subjects and a normal range was established. Raised levels were found in folate deficiency and chronic myeloid leukaemia. Considerably raised levels were found in untreated acute myeloid leukaemia, most often in cases with a marked monocytic element.

The electrophoretic mobility of serum lysozyme

The electrophoretic mobility of serum lysozyme in 2 patients with raised enzyme levels was identical to that of gamma-globulins. Similar mobility was observed after incubation of lysozyme and normal serum. Incubation with one hypogammaglobulinemic serum showed that lysozyme could also acquire alpha2 mobility.

Pathoanatomical features of the kidney in myelomonocytic and chronic lymphocytic leukemia

The kidneys of 18 autopsy cases of myelomonocytic leukemia (MML) were examined for MML-specific features. Nine cases of chronic lymphocytic leukemia (CLL) served as controls. The kidneys of the cases of MML showed macroscopically detectable signs of hemorrhagic diathesis and secondary uric acid diathesis more often than those of CLL. In the MML group most of the kidneys weighed more than the normal average for the corresponding age group, but the average renal weights for the 2 groups were about the same. Renal weight and grade of leukemic infiltration, particularly in MML, revealed no significant positive correlation. In most of the cases of MML there were unevenly distributed poorly defined leukemic, infiltrates in the renal cortex and medulla. The histology resembled that of pyelonephritis. In CLL, on the other hand, the leukemic infiltrates were usually sharply defined and localized in foci in the outer cortex and the corticomedullary border region. Renal dysfunction in cases of MML has been attributed by others to hyperlysozymemia. It was found occasionally but there was no MML-typical morphological substrate in our material. Hyaline droplet change of the tubular epithelium was more frequent and more pronounced in MML than in CLL. However, we also determined that it was nonspecific and that it was not a parameter of cell damage. Tubular hyaline droplet change and the morphological criteria of acute renal failure were not positively correlated with the degree of leukemic infiltration of the kidneys or with the leukemic proliferation as a whole. Instead, they were considered to be signs and symptoms of accompanying or secondary diseases which complicated the leukemia.

The distribution of muramidase (lysozyme) in human tissues

The distribution of muramidase (lysozyme) in normal and pathological human tissues has been studied, using an immunohistological technique. The enzyme was demonstrated in a variety of healthy tissues, including serous salivary acinar cells, lactating mammary tissue, Paneth cells, renal tubular cells, myeloid cells (including eosinophils), and histiocytic cells. In pathological tissues the most striking positivity was encountered in reactive histiocytic cells in granulomatous conditions such as tuberculosis and Crohn's disease. The finding of this study are related to previous reports of the distribution of human and animal muramidase and the implications of patterns of muramidase staining in pathological histiocytes are briefly discussed.

Lysozyme activity and nitroblue-tetrazolium reduction in leukaemic cells

The cytochemical methods for lysozyme and nitroblue-tetrazolium reduction have been used to study the blast cells of acute myeloid leukaemia. Both proved useful in characterizing the cases with predominant monocytic differentiation. THE DEMONSTRATION OF LYSOZYME ACTIVITY HELPED TO DEFINE TWO MAIN GROUPS: (a) with predominantly lysozyme-negative cells (myeloblastic-promyelocytic), and (b) with considerable numbers of positive cells (monoblastic-monocytic). In addition this test was also of value in the differentiation of other leukaemic disorders. Reduction of nitroblue-tetrazolium was also a feature of monocytic differentiation. The combination of these two methods with those for myeloperoxidase and non-specific esterase activity contributes to the cytological characterization of acute myeloid leukaemia.