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Biomedical subjects

H F Pross

Publications and source records attributed to H F Pross.

At least 19 recordsLinked to original sources
PubMed1996

P-glycoprotein-mediated multidrug resistance and lymphokine-activated killer cell susceptibility in ovarian carcinoma.

The sensitivity of tumor cells to lysis by natural killer (NK) and interleukin-2 (IL-2)-activated killer (LAK) cells was studied in three ovarian carcinoma cell lines (2780.9S, SKOV-3, and CHOAUXB1), four multidrug-resistant (MDR) variants, and a melphalan-resistant line. The antitumor activity of LAK cells was evaluated both by 51Cr release and by conjugate formation assays. Four of four P-glycoprotein-positive (P-gp+) MDR ovarian carcinoma cell line variants were lysed by human LAK cells to a greater extent than were their drug-sensitive counterparts. In contrast, a melphalan-resistant ovarian carcinoma cell line that does not overexpress P-gp (P-gp-) did not exhibit an increased susceptibility to LAK cells relative to its parental cell line. Two of the four P-gp+ MDR ovarian carcinoma cell line variants were tested for human NK cell susceptibility and this was found to be unchanged or decreased. The P-gp+ MDR ovarian carcinoma cell line 2780.AD645 showed a higher frequency of tumor cell binding to LAK cells than did the drug-sensitive parental line. A monoclonal antibody (mAb) against a cell surface epitope of P-gp, MRK16, used at 1 microgram/ml, enhanced the LAK susceptibility of P-gp+ MDR ovarian carcinoma cell lines. However, when incubation with 10 micrograms/ml MRK-16 antibody (Ab) was followed by 12.5 micrograms/ml F(ab')2 goat anti-mouse (GAM) immunoglobulin (Ig), the increased LAK susceptibility of P-gp+ MDR cell lines was inhibited. These data strongly suggest that P-glycoprotein-positive MDR ovarian carcinoma cells not only are targets for LAK cells, but are more sensitive than their drug-sensitive parental lines. This is in contrast to their susceptibility to NK cells, which is low to start with and remains unchanged or even decreased in MDR cells. It is postulated here that P-gp or associated changes result in a greater frequency of effector-target cell binding, leading to increased LAK cell cytotoxicity.

ATP Binding Cassette Transporter, Subfamily B, Mem↗
PubMed1993

Lymphoproliferative disease of "LAK cell" precursor large granular lymphocytes in association with celiac disease.

We have investigated a case of lymphoproliferative disease of large granular lymphocytes (LDGL) occurring in association with celiac disease, anemia, neutropenia, and carcinomas of the endometrium, breast, and skin. The large granular lymphocyte (LGL) proliferation was monoclonal, T cell in origin, with T cell receptor beta-chain gene rearrangement, and a CD3+, CD8+, CD16+/- phenotype. In spite of the high frequency of LGL, natural killer (NK) cell activity was absent. Stimulation with interleukin-2 in vitro, however, resulted in high lymphokine-activated killer (LAK) cell activity against NK-resistant targets. The T-cell nature of the LAK precursor cells is in contrast to the majority seen in normal peripheral blood. Therapeutic trials of cyclosporin A, low-dose cyclophosphamide, and levamisole were unsuccessful in reducing transfusion requirements. This case is unique in the association of LDGL with celiac disease. It is also unique in that the patient had been followed for several years prior to the onset of the LDGL. The case extends the list of lymphoproliferative disorders documented to be associated with celiac disease and, conversely, adds to our knowledge of lymphoproliferative disorder of LGL and its "dysimmune" manifestations.

Celiac Disease↗
PubMed1993

Effects of lovastatin on natural killer cell function and other immunological parameters in man.

Suppression of cholesterol synthesis by 3-hydroxy-3-methylglutaryl-coenzyme A (HMG-CoA) reductase inhibitors, such as lovastatin, has been shown to inhibit mitogen stimulated proliferation of natural killer (NK) cells and other lymphocytes in vitro. This effect is only partially overcome by provision of exogenous free or lipoprotein cholesterol but is reversed by mevalonate, suggesting that proliferating lymphocytes have a specific requirement for a nonsterol isoprenoid product of mevalonate. The effect of lovastatin (20 mg bid) on a range of immune function parameters was determined in a randomized, placebo-controlled, double-blind ex vivo study in 52 patients with primary hypercholesterolemia. No significant differences (P < 0.05) were found between lovastatin and placebo groups for basal NK or interleukin-2 (IL-2)-induced cell-mediated cytotoxicity, PHA-stimulated lymphocyte proliferation, or relative numbers of T lymphocytes (CD3+), B lymphocytes (CD19+), total NK cells (CD3-, CD16+, CD56+) and CD57+ NK cells or in immunoglobulin levels after 4 or 8 weeks of treatment. In contrast to previous in vitro data, no statistically or clinically significant changes were observed in any parameter of lymphocyte function in patients treated with lovastatin.

Adult↗
PubMed1989

Studies of lymphokine-activated killer (LAK) cells. I. Evidence using novel monoclonal antibodies that most human LAK precursor cells share a common surface marker.

Separation of LAK precursor (LAKp) cells (as defined by LAK effector generation after incubation with IL-2 for 7 d) from cells with NK activity/LGL morphology was achieved on Percoll gradients using a longer, slower centrifugation than that used for optimal NK enrichment. mAb were generated using the various Percoll fractions as the immunizing cells and used for separation and depletion studies. Two mAbs DM-1 (IgM,k) and DM-2 (IgM,k) recognizing 2-15% and 15-30% of PBL, respectively, abrogated a large proportion of LAK generative potential after complement depletion, but had little effect on NK or LAK effector activity. Cell sorting experiments indicated that the majority of LAKp cells are found within the DM-1+ population and that DM-1+ cells are not simply an accessory cell required for LAKp generation. Further, these two mAbs do not recognize cells that are responsible for generating cytotoxicity during MLC or co-culture with the PR-1 EBV lymphoblastoid cell line. Western blot analysis indicated that DM-1 and DM-2 recognize a 38,000 and 44,000 dalton moiety, respectively. The frequency of cells bearing these antigens and the intensity of cell surface staining decreased during the 7-d culture period, suggesting that these antibodies recognize determinants found only at the precursor level. These findings indicate that cells other than NK effectors or mature T cells are capable of generating a LAK cell response. These LAK precursor cells share a common differentiation surface antigen and are different from AK or antigen-specific CTL precursors. The possibility exists that these cells are identical to, or include, the NK precursor cell.

Animals↗
PubMed1987

Immunologic studies of subjects with asthma exposed to formaldehyde and urea-formaldehyde foam insulation (UFFI) off products.

There has been concern in recent years as to the health hazards of exposure to potentially carcinogenic or immunotoxic substances in the environment. This study was done to determine the effects of exposure to urea-formaldehyde foam insulation (UFFI) off products on various hematologic and immunologic parameters in subjects with asthma: complete blood count and differential, erythrocyte sedimentation rate, lymphocyte subpopulations (E-rosetting, T3, T4, T8, B73.1, and Fc receptor positive lymphocytes and large granular lymphocytes), lymphocyte response to phytohemagglutinin and formalin-treated red blood cells (Form-RBC), serum antibody against the Thomsen-Friedenreich RBC antigen and against Form-RBC, and natural killer (NK), interferon (IFN)-boosted NK (IFN-NK), and antibody-dependent cell-mediated cytotoxicity. Four control subjects with asthma from conventionally insulated homes (control group) and 23 subjects with asthma from UFFI-insulated homes (home group) were exposed to placebo, formaldehyde, dust, and UFFI off gas at levels ordinarily found in UFFI-containing homes for four separate periods in an environmental chamber. Immunologic testing was carried out before the exposure series and 1 day after completion 7 days later as part of an investigation of respiratory and possible allergic effects of such exposure. Data from the UFFI-insulated home group were not significantly different from data of the normal conventionally insulated home control group for any of the variables studied, either before or after UFFI exposure. Paired t tests comparing data from each of the two groups before and after UFFI exposure demonstrated minimal but statistically significant increases in percent eosinophils and T8 positive cells in the UFFI-insulated home group only. Although NK, relative NK, and IFN-NK were normal in all groups, IFN-NK assays by use of a low concentration of alpha-interferon demonstrated a statistically significant decrease in NK response to IFN in both the control and UFFI-insulated home groups after UFFI exposure. These differences were not observed at optimum levels of IFN stimulation. These data indicate that long-term exposure to UFFI off products in the home apparently had no effect on the immunologic parameters studied. Short-term exposure resulted in minor immunologic changes in this subject population.

Antibody Formation↗
PubMed1985

Studies on natural, antibody-dependent, and interleukin-2-activated killer-cell activity of a patient with mucolipidosis III as a test of the mannose-6-phosphate lytic acceptor hypothesis.

The natural (NK), antibody-dependent (K), and interleukin-2-generated (LAK) killer-cell activity of a patient with mucolipidosis III (ML III; an autosomal recessive defect in UDP-N-acetylglucosamine: lysosomal enzyme N-acetylglucosamine-1-phosphotransferase) was studied to determine whether or not the defect in the phosphorylation of lysosomal enzyme mannose residues resulted in a failure of target-cell lysis, as would be predicted from recent studies showing NK inhibition by phosphorylated sugars, especially mannose-6-phosphate. The patient was studied in parallel with normal donors known to be at the high and low extremes of NK activity. The following results were obtained: NK activity was markedly elevated against K562, Molt-4, human fibroblasts, HL-60, and MeWo to levels approximately one to two times that of our previous highest donor and five times the mean of normal donors previously tested. Interleukin-2-generated killer-cell activity and antibody-dependent cell-mediated cytotoxicity against antibody-coated P815 cells were normal and increased, respectively. HNK-1-positive cells were normal in frequency (7.3 +/- 1.7%), while lytic conjugates were proportional to activity (3.9 +/- 0.6 vs 2.7 +/- 0.4% for the "high" donor), and this was attributable to an increased proportion of lytic cells. The addition of fresh serum from the ML III patient had no effect on the NK activity of normal donors and the effects of preincubation with interferon (enhancement), monensin (inhibition), fructose-6-phosphate (inhibition), and mannose-6-phosphate (inhibition) were identical to those seen using lymphocytes from normal donors. Studies on the NK activity of the parents and two normal female siblings showed that the father's NK activity was high, the mother's was low, and both siblings' was intermediate but low. The data obtained suggest that the inability of lymphocytes to phosphorylate lysosomal enzyme mannose residues had no effect on NK-, K-, or LAK-cell function and that the mechanism of target-cell lysis is independent of either a mannose-6-phosphate-bearing lytic moiety or a mannose-6-phosphate-dependent ligand mechanism.

Adult↗
PubMed1984

Natural killer cell activity in women at "high risk" for breast cancer, with and without benign breast syndrome.

This study is an analysis of natural killer cell (NK) function in 155 women repeatedly tested over a 5-year period while attending breast screening clinics because of one or more of the following risk factors: family history-breast cancer in a close female relative (relative risk = 1.2-9); personal history-early menarche, non-parity, late menopause, etc. (relative risk = 1.3-3); clinical benign breast syndrome-localized and diffuse (relative risk = 2-4). Contrary to expectations, the high-risk group as a whole had significantly higher than normal relative NK function vs K562 (1.21 +/- 0.06 vs 1.00 +/- 0.06) (p less than 0.02). Division into subgroups showed that the NK activities in patients with positive family histories, personal histories, or both, were exactly the same as normal values and that the increased NK function in the high-risk group as a whole was due to those donors with benign breast syndrome (BBS). This group was also subdivided and the results were compared with the high-risk patients with no BBS. The NK activity of the group having diffuse BBS (1.67 +/- 0.05, n = 32) was significantly higher than that of the "No BBS" group (1.07 +/- 0.07, n = 102) (p less than 0.025). A paired "t'-test performed on data from 7 patients who had no BBS and diffuse BBS at different times showed a significant difference of p less than 0.001, suggesting that the elevated NK activity is a reaction to the hormonal factors which cause this condition.

Breast Neoplasms↗
PubMed1984

The standardization of NK cell assays for use in studies of biological response modifiers.

This paper deals with the standardization of human natural killer (NK) cell assays for the sequential evaluation of patients with various disease states, or who are being treated with biological response modifiers. The method is described for the calculation of lytic units which results in numbers proportional to effector cell activity. It is shown that normal donors are relatively consistent in their cytotoxicity, making it possible to use a 'bank' of normal controls against which patients data can be normalized. Cryopreserved lymphocytes, as well as fresh lymphocytes, can be used as controls. Under the usual conditions for recovering cryopreserved lymphocytes, NK activity is markedly reduced; but by preincubation of the lymphocytes at 37 degrees C for 5 h or more the activity is recovered. A number of currently used methods for the selection of controls are described and discussed with respect to their practicality and validity. The principle problem with currently used methods is the necessity for a large number of controls so that a uniform distribution of NK activity about the 'true' normal is assured. The method which we advocate in this paper is based on the selection of normal control donors from a group of individuals who have been tested repeatedly over several months or years and whose NK activity relative to normal donors as a whole can be stated with reasonable confidence. These values are then used as correction factors which are applied to the relevant control donor's cytotoxicity every time that that person is used. In any particular experiment the mean of the corrected control lytic unit values is used as the denominator for the calculation of patient NK activity relative to normal. This method can be applied 'retrospectively' if a variety of donors have been used repeatedly. Two 'tests' of the methodology are described, with the following results: (1) the relative NK activity of a randomly selected group of normal women, whose data were handled as if they were a patient population, was approximately one, and (2) complete Freund's adjuvant, administered intradermally to patients with resected lung cancer, caused an increase in natural killer cell activity compared to pretreatment levels. The use of these methods should make it possible to derive meaningful NK results which are comparable from laboratory to laboratory.

Blood Preservation↗
PubMed1984

The effect of specific and nonspecific immunotherapy on natural killer cell activity in patients with non-small-cell lung cancer.

Fourteen patients with stages I and II non-small-cell lung carcinoma receiving adjuvant immunotherapy after surgery were studied serially for natural killer (NK) cell cytotoxicity assays. Seven patients received active nonspecific immunotherapy with Freund's complete adjuvant alone and seven patients received active specific immunotherapy with tumor-associated antigen plus Freund's complete adjuvant. Both groups were analyzed as a single group in view of the lack of any difference in the results. The results indicated that NK-cell cytotoxicity v K562 was lower in untreated patients than in normal controls, but the difference was not significant. There was no evidence of specific cytotoxicity v the lung cell line A549 in untreated patients when compared with normal controls. Compared with pretreatment values, elevated cytotoxicity v both K562 and A549 was observed at every post-treatment time point tested, and this was statistically significant at several time points by a paired t test. No specific effect was noted after immunization with lung antigen on cytotoxicity against the lung cell line A549. Other correlations studied did not show any relationship between delayed hypersensitivity skin testing or serum carcinoembryonic antigen levels and NK-cell cytotoxicity. It is concluded that NK-cell reactivity was increased nonspecifically by active specific and nonspecific immunotherapy. This increase seems to peak at the 12-month period and was significant when compared with pretreatment levels.

Adjuvants, Immunologic↗
PubMed1984

Enhanced natural killer sensitivity with concomitant clonal selection for cells bearing homogeneously staining regions in the human melanoma cell line MeWo upon induction of differentiation with theophylline.

Culture of the human melanoma cell line MeWo in the presence of 1 mM theophylline was associated with an increase in susceptibility to natural killer (NK)-mediated cytolysis. The phenomenon was detected as early as 72 hours after initiation of theophylline treatment, reaching maximum values at 3-4 weeks and remaining stable for longer than 3 months of testing, provided the cells were maintained in the presence of theophylline. The alteration in target sensitivity was selective for NK-mediated cytolysis, since other mechanisms of cell-mediated cytolysis, including antibody-dependent cell-mediated cytotoxicity and monocyte-mediated and lectin-induced cytolysis, were comparable between untreated and treated cells. The enhanced susceptibility of theophylline-treated cultures to NK lysis, as compared to NK lysis susceptibility of untreated MeWo cells, was not significantly changed by pretreatment of effector lymphocytes with interferon. Evidence for differentiation in theophylline-treated cultures was obtained. In addition, however, cytofluorometric and karyologic analysis revealed the existence of two subpopulations of differing ploidy in the MeWo line. The hypodiploid, NK-sensitive subpopulation, bearing homogeneously staining regions on two chromosomes, could be selected by growth in theophylline. Therefore, selection of subpopulations in heterogeneous tumor cell lines by chemical inducers suggests an alternative and novel mechanism for enhancement of NK sensitivity.

Cell Cycle↗
PubMed1983

Modulation of K562 cells with sodium butyrate. Association of impaired NK susceptibility with sialic acid and analysis of other parameters.

Neuraminidase treatment of parental and butyrate-induced K562 tumor cells was associated with an increase in natural killer (NK) susceptibility of these target cells. The degree of enhancement with neuraminidase was significantly greater for the NK-resistant (NRR) butyrate-differentiated K562 cells so that the relative difference between the parental NK-sensitive (NKS) K562 line and its induced NKR variants, in terms of NK sensitivity, was no longer five- or six-fold but only two-fold. The predominant reason for the altered NK susceptibilities of the target cells after neuraminidase treatment was an increase in the target-cell-binding ability of these cells as assessed by a direct conjugate-forming cell assay using Percoll-enriched NK cells and cold target competition assays. The enhancement did not appear to be due simply to an increased membrane-membrane attraction caused by a reduction of net negative cell surface charges since protamine sulphate, a positively charged molecule, had no effect on NK activity. Compared with the NKS parental K562 tumor cells, the NKR butyrate-induced cells had 3.6- to 4.0-fold higher sialo-transferase activities and were associated with significantly greater amounts of cell surface sialic acid detected both in sialyl glycoproteins (2.2- to 2.9-fold higher) and particularly within ganglioside extracts (6.2- to 13.6-fold higher). In conformity with the marked neuraminidase enhancement of NK-mediated cytolysis of the butyrate-induced targets, these NKR cells were associated with significantly enhanced levels of neuraminidase-accessible sialic acid compared to the NKS parental K562 cell line. Other parameters such as sensitivity to superoxide radicals, intrinsic superoxide dismutase levels, altered membrane repair mechanisms and transferrin competition, were not significantly different between the NKS and NKR target phenotypes. Sugar inhibition studies demonstrated an enhanced inhibition against the butyrate-induced cells with a variety of neutral sugars. The degree of inhibition with phosphorylated sugars was comparable between the parental and induced K562 tumor target cells and is consistent with our previous findings showing that these hexose phosphates may be inhibiting cytolysis at a step independent of target-cell recognition.

Butyrates↗
PubMed1983

The effect of unphosphorylated and phosphorylated sugar moieties on human and mouse natural killer cell activity: is there selective inhibition at the level of target recognition and lytic acceptor site?

A number of different sugars were investigated for their effect on human and mouse natural killer cell (NK)-mediated cytolysis. From the pool of nonphosphorylated sugars, D-mannose, N-acetyl-D-glucosamine (NAcGlc), D-glucose, and, to a lesser extent, beta-gentiobiose were found to inhibit human NK cytolysis. Mouse NK activity against YAC-1 target cells was reduced consistently in the presence of D-mannose and NAcGlc only. The sugars, NAcGlc, D-glucose, and beta-gentiobiose, were specifically inhibitory against NK-mediated cytolysis with no inhibitory effects being observed against ADCC, monocyte-mediated cytolysis, or CTL activity. Pretreatment and washing at either the target or effector cell level as well as direct target binding assays using Percoll-purified NK cells indicated that at least NAcGlc and beta-gentiobiose function at the recognition stage of NK cytolysis. D-Mannose, which was the most effective nonphosphorylated sugar inhibitor, was capable of inhibiting all cell-mediated cytotoxic mechanisms tested (NK, ADCC, monocyte, and CTL) and its action did not appear to be solely due to an impairment in the recognition event. All the phosphorylated sugars caused significant inhibition of human and mouse NK-mediated cytolysis, although repeated analyses of sugar titration curves consistently showed mannose-6-phosphate (Man-6-P) to be the most effective inhibitor. Inhibition with the phosphorylated sugars was apparent against all cytotoxic mechanisms investigated. It is possible that these sugars may function as general metabolic inhibitors or may activate a common signal which negatively regulates cell-mediated cytotoxic mechanisms. Nevertheless, the relative degree of inhibition with the majority of these sugars (particularly Man-6-P) was greater against NK and ADCC activity than against monocyte and CTL activity. Furthermore, studies with selected well-characterized human and mouse NK-resistant target cells strongly indicated that these sugars, particularly Man-6-P, compete at an acceptor site responsible for the uptake of the NK lytic factor, which is independent of the recognition structure(s).

Animals↗
PubMed1983

The Chediak-Higashi gene in humans. III. Studies on the mechanisms of NK impairment.

Lymphocytes from six Chediak-Higashi (CH) patients were markedly depressed in their ability to lyse tumour cell targets in both 51Cr release and single cell cytotoxicity assays. The frequency of lymphocytes bearing the OKM1 marker and the frequency of T3+, T4+, T8+, Ia+, Mo1+, Mo2+ and B1+ cells was normal among sheep erythrocyte rosetting (E+) and non-rosetting (E-) peripheral blood leucocytes analysed by flow cytofluorography. Cells expressing the NK shared markers, OKM1, mac-1, FcR, and the characteristic large granular lymphocyte (LGL) morphology of NK cells were also present in normal numbers in the highly enriched NK fraction separated on Percoll density gradients. This fraction did not contain detectable numbers of cells expressing the Mo2 marker of human monocytes. Therefore most of the cells stained by monoclonal OKM1 and mac-1 in this fraction are likely NK cells, rather than monocytes, and we conclude that the size of the NK pool in CH patients is probably normal. The capacity of CH lymphocytes to recognize and bind to tumour cells was also normal as was the subsequent burst of oxygen intermediates produced by the NK cells in a chemiluminenscence assay. We have shown elsewhere that O2- generation is directly involved in activating subsequent steps in the NK cytolytic pathway. These results suggest that NK cells in CH patients are present in normal frequency but are blocked at some post-recognition, post-activation step in the cytolytic pathway subsequent to the burst of oxygen intermediates but preceding the lethal hit.

Adolescent↗
PubMed1982

Studies of human natural killer cells. I. In vivo parameters affecting normal cytotoxic function.

The results of natural killer cell (NK) studies on 539 normal healthy donors tested from once to 213 times over a seven-year time span have been presented. NK activity did not vary with donor blood group, Rh type or (in a small sample) HLA type. There was a slight but significant increase in NK activity from birth to adulthood, and between males an females. The male/female difference was present at birth and persisted through adulthood. The relative NK activity of individual donors tested repeatedly over many years was remarkably consistent in spite of variability in the absolute cytotoxicity observed. The expression of NK data in terms of relative NK was found to be superior to other methods, and the values obtained were found to be independent of the NK-sensitive target cell used. Although age and sex differences in NK activity are slight, their existence should be considered when studies of NK activity in patients are analysed.

Age Factors↗
PubMed1982

The biology of the human natural killer cell.

Natural killer (NK) cells in the human are a population of large granular lymphocytes (LGL) with at least one unique surface antigen not expressed on cells of other lineages. NK-target-cell interaction appears to involve carbohydrate recognition and, following binding, the NK cells are induced to generate O2-, transmethylate membrane phospholipids, and activate phospholipase A2. Some or all of these activities trigger a cascade of events which ultimately leads to the secretion of a substance toxic to the target cell. A variety of genes controls various steps in this cytolytic pathway. There is a good deal of evidence in the mouse, and some in the human, that NK cells play a role in host surveillance against tumor development, resistance to viral infections, and, possibly, hematopoietic regulation.

Animals↗
PubMed1982

Studies of human natural killer cells. III. Neutropenia associated with unusual characteristics of antibody-dependent and natural killer cell-mediated cytotoxicity.

A 52-year-old Caucasian man with chronic neutropenia and recurrent infections was found to have an increased proportion of peripheral T lymphocytes having Fc receptors for IgG (T gamma ). Although levels of antibody-dependent cell-mediated cytotoxicity (ADCC) and "natural" killing (NK) by unfractionated lymphocytes were similar to those of a control donor, the frequency of KN cells was markedly increased. Removal of E rosette-forming cells eliminated both NK and ADCC by the patient's peripheral blood, in marked contrast to the enhanced cytotoxicity seen with control lymphocytes. Both normal and patient ADCC and NK functions were removed by depletion of Fc receptor-bearing cells. These depletion experiments proved that all of the patient's killer cells were E rosette-forming T gamma cells, in contrast to the heterogeneous pattern of null gamma and T gamma killer cells seen in the blood of normal donors. The homogeneity of the T gamma proliferation suggested that ADCC and NK were mediated by the same cell type, albeit acting by different mechanisms. The addition of the patient's serum and lymphocytes to chromium-labelled normal granulocytes caused a low but significant level of cytotoxicity, indicating that the patient's neutropenia may have been caused by a similar mechanism in vivo. There was no evidence of complement-dependent serum antibody-mediated neutrophil lysis, but one serum sample taken over the course of the patient's disease agglutinated granulocytes from four of five donors tested.

Agglutination↗