Abnormal Neutrophil Chemotaxis after Successful Bone Marrow Transplantation

Twenty patients with self-sustaining hematopoiesis were evaluated for neutrophil functions and bone marrow histology 7 to 34 months after bone marrow transplantation (BMT) (7 allogeneic, 13 autologous) performed for acute leukemia in complete remission (11 patients), Hodgkin's lymphoma (2 patients), chronic myeloid leukemia (6 patients) or severe aplastic anemia (1 patient). The chemotactic response toward zymosan-treated serum was severely depressed (<35% of normal) in peripheral neutrophils of 11 patients (2 allogeneic and 9 autologous BMT) and moderately defective (35-70% of normal) in 5 others (2 allogeneic and 3 autologous BMT). On the other hand, phagocytic activity, activation of the metabolic burst and surface expression of CD11/CD18 molecules were within normal limits or moderately increased. The chemotactic defect was independent of age, sex, conditioning regimen and the time period after marrow infusion. The incidence of defective chemotaxis was much greater in patients receiving an autologous BMT (92% of the patients) than in those who had an allogeneic BMT (57% of the patients). Simultaneous bone marrow biopsy studies showed significant stromal alterations in most of our patients; since the bone marrow microenvironment plays an essential role in the process of blood cell formation and release, these observations suggest that defective neutrophil chemotaxis may well serve as a marker of abnormal post-transplant hematopoiesis.

The diagnosis of early psoriatic arthritis

Psoriatic arthritis (PsA) is a chronic inflammatory joint disease with heterogeneous clinical presentation and unpredictable course but often with a tendency to irreversible joint damage. Joint damage can occur early in the disease also in the absence of significant clinical signs of arthritis. These observations and the current availability of effective treatments in controlling skin and joint disease underline the importance of early diagnosis of PsA. The use of specific questionnaires for screening patients at risk of psoriatic arthritis, knowledge of new classification criteria for PsA and especially the proper use of new imaging techniques are all important steps in achieving the goal of early diagnosis of PsA. The dermatologist may play a key role in this regard supported, when necessary, by the collaboration of the rheumatologist and radiologist.

The protein kinase C inhibitor AEB071 (sotrastaurin) modulates migration and superoxide anion production by human neutrophils in vitro

We examined the effect of the protein kinase C-selective inhibitor AEB071 (sotrastaurin) on neutrophil functions in vitro. Pre-incubation with AEB071 at concentrations similar to those reached during in vivo therapy significantly reduced cell capacity to migrate toward three different chemo-attractants and to produce superoxide anions (O₂⁻) in response to phorbol myristate acetate (PMA) or to N-formyl-methionyl-leucyl-phenylalanine (fMLP). AEB071 also significantly inhibited the O₂⁻ overproduction induced by fMLP in neutrophils primed with tumor necrosis factor alpha (TNF-α) or granulocyte/macrophage-colony stimulating factor (GM-CSF). This inhibition was not linked to fMLP-receptor down-regulation since the drug had no effect on either fMLP-receptors or fMLP-induced CD11b membrane expression. When the activity of AEB071 was compared to that of the conventional protein kinase C (PKC) inhibitor Gö6850 (which, like sotrastaurin, inhibits classical and novel PKC isoforms), Gö6976 (an inhibitor of α and α PKC isoforms) and rottlerin (a prevailing δ PKC isoform inhibitor), AEB071 at an equimolar concentration of 3 μM (close to the maximum drug concentration reached in patients treated with AEB071) caused significantly more inhibition on both chemotactic response and superoxide production. These in vitro findings suggest that neutrophils may offer a cellular target for AEB071 activity in vivo.

Successful Cyclosporine Treatment in a Case of Amicrobial Pustulosis Associated with Immunological Abnormalities

Amicrobial pustulosis associated with autoimmune diseases (APAD) is a clinical entity which was described only recently and few cases are reported in the literature. This condition is characterized by recurrent acute onset with pustular lesions predominantly involving skin folds, genitals, scalp and external auditory canals of young women. The etiopathogenesis of APAD is unknown and the most effective therapeutic treatment seems to be systemic corticosteroids. We describe the case of a 16-year old female patient suffering from APAD successfully treated with cyclosporine A.

Risk factors for a first thrombotic event in antiphospholipid antibody carriers. A multicentre, retrospective follow-up study

OBJECTIVES

To asses risk factors for a first thrombotic event in antiphospholipid antibody (aPL) positive carriers and evaluate the efficacy of prophylactic treatments.

METHODS

Recruitment criteria were age 18-65 years, no history of thrombosis, positivity for lupus anticoagulant and/or IgG/IgM anticardiolipin antibody (aCL) on > or =2 occasions at least 6 weeks apart. Demographic, laboratory and clinical parameters were collected at enrolment and at the time of the thrombotic event.

RESULTS

370 patients/subjects (mean (SD) age 34 (9.9) years) were analysed retrospectively for a mean (SD) follow-up of 59.3 (45.5) months. Thirty patients (8.1%) developed a first thrombotic event during follow-up. Hypertension and medium/high levels of IgG aCL were identified by multivariate logistic regression analysis as independent risk factors for thrombosis. Thromboprophylaxis during high-risk and long-term periods was significantly protective.

CONCLUSIONS

Hypertension or medium/high titres of IgG aCL are risk factors for a first thrombotic event in asymptomatic aPL carriers and primary prophylaxis is protective.

Effect of Efalizumab on neutrophil and monocyte functions in patients with psoriasis

We evaluated the effect of efalizumab on neutrophil and monocyte functions. The in vitro pre-incubation with efalizumab concentrations similar to those reached during in vivo therapy almost completely saturated CD11a binding sites without affecting the membrane expression of CD11b, CD128a or CD128b. There was a significant reduction in the chemotactic activity of the pre-treated cells toward three different chemo-attractants, whereas their phagocytic capacity and production of oxygen radicals remained unchanged. One month after the administration of efalizumab to five patients with psoriasis (T1) circulating neutrophil counts increased by 34% from pre-therapy (T0) with no change in the number of monocytes. In the same patients the CD11a binding sites on phagocytes were >90% saturated, and there was also a significant down-modulation on neutrophils (44% of T0) and monocytes (63% of T0). In line with in vitro results, efalizumab treatment caused a significant deficiency in the chemotactic properties of neutrophils and monocytes, but no changes in phagocytosis, oxidative burst, production of pro-inflammatory cytokines or the membrane expression of CD11b, CD128a and CD128b. Our findings suggest that neutrophils and monocytes may be among the targets of efalizumab activity in patients with psoriasis.

[Bisphosphonate-associated osteonecrosis of the jaw in rheumatology: a systematic review]

Osteonecrosis of the jaw (ONJ) is a well-known devastating side effect of parenteral bisphosphonate therapy for cancer. Several ONJ cases have been reported in patients taking oral bisphosphonates for osteoporosis or Paget's disease. Even if the number of cases of ONJ in patients taking oral bisphosphonates are still rare compared to the total exposure, rheumatologists treating bone diseases with bisphosphonates must be aware of this new complication, allowing for prevention and early diagnosis. The patients must be informed on the benefit/risk of bisphosphonate therapy and, when necessary and possible, alternative therapy for postmenopausal osteoporosis should be considered. The need for the patient to be dentally fit and to maintain this state forever should be part of the informed consent for bisphosphonate treatment. It is uncommon for rheumatologists to ask about dental problems but this new bisphosphonate- associated complication highlights the need for this to change. In this paper we review the literature available on this newly described bisphosphonate-induced complication with particular emphasis on ONJ cases related to the use of oral bisphosphonates.

CD69 expression on neutrophils from patients with rheumatoid arthritis

OBJECTIVE

Since the early activation antigen CD69 has been implicated in the pathogenesis of some inflammatory diseases, we evaluated the expression of the molecule on peripheral blood (PB) and synovial fluid (SF) neutrophils obtained from RA patients and its possible correlation with PB and SF cytokine concentration.

METHODS

CD69 membrane expression (and CD11b as control marker) was assessed by indirect immunofluorescence and flow cytometry analysis on purified PB and SF neutrophils. Cytokine levels (GM-CSF, IFN-gamma, TNF-alpha) in plasma and SF supernatants were measured by ELISA.

RESULTS

CD69 was absent on control neutrophils, while it was expressed on PB neutrophils from RA patients although no detectable GM-CSF, IFN-gamma or TNF-alpha was observed in their plasma. CD69 expression was still more evident on SF neutrophils from RA patients; 59% had detectable levels of INF-gamma in their SF while GM-CSF and TNF-alpha were detectable in SF from 95% and 33% of RA patients, respectively. However, no correlation was observed between cytokine concentrations and CD69 expression on SF neutrophils. SF but not PB neutrophils from RA patients expressed increased amounts of CD11b when compared to control PB neutrophils without any correlation with CD69 membrane expression.

CONCLUSION

The activation antigen CD69 is significantly expressed on PB and SF neutrophils from RA patients. However, the mechanism(s) of induction and its possible role in the pathogenesis of RA remain to be defined.

Successful treatment of pure red cell aplasia in systemic lupus erythematosus with cyclosporin A

We report a patient with longstanding systemic lupus erythematosus (SLE) who developed pure red cell aplasia (PRCA). This condition is rare in connective tissue diseases and is reported in 32 previous cases of SLE in literature. Our patient recovered, apparently in response to treatment with high dosage of corticosteroids, but relapse occurred when the prednisone dosage was tapered down to 10 mg/day. The patient was successfully treated with cyclosporin A with no recurrence of the disease in the last 2 years.

Effectiveness of IFN-gamma for liver abscesses in chronic granulomatous disease

In chronic granulomatous disease, interferon-gamma (IFN-gamma) significantly reduces the incidence and severity of recurrent infections, but its effectiveness administered ex novo during acute infection has been reported in only one case. In this report, we describe two adult brothers with chronic granulomatous disease treated successfully with IFN-gamma for acute liver abscesses. Two brothers with severe recurrent infections of unknown origin were hospitalized for septic fever, malnutrition, and ultrasonographic evidence of liver abscess. Autosomal recessive chronic granulomatous disease was diagnosed based on lack of superoxide anion production by phagocytes and absence of p47-phox protein. An antibiotic regimen specifically directed against Staphylococcus aureus was ineffective, whereas treatment with 50 microg/m2 IFN-gamma s.c. thrice weekly induced complete healing with scarring within 3 months. No septic recurrence was observed during a 4-year follow-up period. In chronic granulomatous disease, IFN-gamma is effective not only in preventing but also in healing life-threatening acute infections.

Recurrent proximal white subungual onychomycosis associated with a defect of the polymorphonuclear chemotaxis

Proximal white subungual onychomycosis (PWSO) is a rare form of nail infection that occurs almost exclusively in immunocompromised patients. Initially, in several reports, PWSO was described in ARC and AIDS patients. Later this pattern of onychomycosis was observed in patients with renal transplants, who received immunosuppressive therapy, and recently in a woman with active systemic lupus erythematosus (SLE) treated with systemic steroid therapy. We report a case of recurrent PWSO in a woman affected by a defect of polymorphonuclear chemotaxis. The association between PWSO and a defect of neutrophil chemotaxis, not yet described in the literature, suggests a point of discussion about the role of polymorphonuclear leucocyte functions in the defense mechanisms of the host affected by dermatophytosis. In this report the close association between PWSO and an immunocompromised condition is once again described. For this reason the authors emphasize the importance of investigating the common and uncommon causes of immunodeficiency in all patients affected by PWSO.

Development of phagocytic function of cultured human monocytes is regulated by cell surface IL-10

Monocytes differentiating in vitro into macrophages increase their capacity to ingest particles via FcgammaR and CR3. Because human recombinant IL-10 is a potent up-regulator of phagocytosis in human monocytes, we investigated whether spontaneously produced IL-10 could be a signal for the modulation of phagocytosis by cultured monocytes. We show here that culture of monocytes in the presence of anti-IL-10 mAb completely abolished up-regulation of phagocytosis of both EIgG and EIgMC3bi, suggesting a role for spontaneously produced IL-10 in the modulation of phagocytosis by cultured human monocytes. The inhibition exerted by anti-IL-10 mAb on the development of FcgammaR-mediated ingestion was dependent on the concomitant inhibition of FcgammaRIII induction in cultured cells. On the other hand, a similar down-regulation of CR3 expression was not involved in the inhibitory effect exerted by anti-IL-10 mAb on the development of CR3-mediated ingestion. Monocytes secreted detectable levels of IL-10 when cultured in medium but the concentrations of IL-10 in the supernatants decreased with length of time in culture, the decrease being completely reversed by anti-IL-10 mAb. In addition, we showed that monocytes expressed immunoreactive IL-10 on their surface and this expression increased during differentiation into macrophages. Whether this IL-10 was bound to specific membrane receptors or it was an integral membrane protein remains to be determined; however, this latter possibility is consistent with our observations that IL-10 did not elute with acid treatment and exogenous IL-10 did not increase surface staining of monocytes. Our data indicate that human mononuclear phagocytes express IL-10 on their membrane and suggest that this cytokine may represent an autocrine signal for the increased phagocytic function observed during differentiation of monocytes into macrophages.

Interleukin-10 down-regulates oxidative metabolism and antibody-dependent cellular cytotoxicity of human neutrophils

The authors investigated the ability of interleukin-10 (IL-10) to modulate some constitutive or interferon-gamma (IFN-gamma)-enhanced activities of human neutrophils. An 18h culture of neutrophils with IL-10 dose-dependently down-regulated their capacity to produce O(2)- and lucigenin-amplified chemiluminescence in response to n-formyl-methionyl-leucylphenyl-alanine (FMLP). Furthermore, treatment of neutrophils with IL-10 decreased in a dose-dependent fashion, their capacity to lyse antibody-coated sheep erythrocytes. Membrane expression of Fc gamma RI, Fc gamma RII, Fc gamma RIII, CR1, CR3 and Fc gamma R- and CR-mediated phagocytosis were not modified by the cytokine. Culture of neutrophils with IFN-gamma (100 U/ml) did not modify their Fc gamma R- and CR-mediated phagocytosis, but significantly up-regulated Fc gamma RI and CR3 membrane expression as well as their oxidative metabolism and antibody-dependent cellular cytotoxicity (ADCC). When IL-10 and IFN-gamma were added simultaneously to neutrophil culture, IL-10 dose-dependently reduced IFN-gamma-induced increase of CR3 expression, O(2)- production (in response to both FMLP and phorbol 12-myristate 13-acetate, or PMA) and ADCC, but did not change Fc gamma RI expression on phagocytes. These results demonstrate that IL-10 is a significant neutrophil deactivator and provide new information on the role of IL-10 in the regulation of neutrophil-mediated inflammatory processes.

The neuropeptide alpha-MSH has specific receptors on neutrophils and reduces chemotaxis in vitro

The proopiomelanocortin-derived peptide alpha-melanocyte stimulating hormone (alpha-MSH) has potent anti-inflammatory effects in all animal models of inflammation against which it has been tested. Understanding of the mechanism by which this occurs is incomplete, although there is recent evidence for alpha-MSH receptors in murine and human macrophages and for modulation of production of proinflammatory cytokines and related mediators by alpha-MSH. Because of the prominence of neutrophils in early stages of inflammatory reactions where alpha-MSH is effective, we examined human neutrophils for evidence of mRNA for alpha-MSH receptors and for inhibition of neutrophil chemotaxis. There was accumulation of mRNA for melanocortin receptor 1 (MC1) in RT/PCR product from neutrophils stimulated with interferon and LPS. In subsequent studies alpha-MSH inhibited migration of neutrophils from most normal volunteers when the cells were placed in FMLP or IL-8 gradients. The inhibition by alpha-MSH could be traced to alterations in cAMP in neutrophils. The presence of alpha-MSH receptor message in neutrophils is consistent with the established anti-inflammatory effects of the peptide. Direct inhibition of neutrophil chemotaxis likely contributes to the anti-inflammatory activity of alpha-MSH.

Amicrobial pustular dermatosis of cutaneous folds associated with autoimmune disorders: a new entity?

BACKGROUND

An unclassified amicrobial pustular dermatosis particularly affecting the main cutaneous folds, external auditory canals and scalp and coexisting with systemic lupus erythematosus has been recently described.

OBJECTIVE

We studied 3 young females bearing such cutaneous manifestations in association with subacute cutaneous lupus erythematosus, celiac disease and various serum autoantibodies, respectively, in order to further characterize this possibly new entity.

METHODS

Various routine and immunological laboratory tests, histopathologic and direct immunofluorescence examinations and in vitro studies of neutrophil function were performed in each patient.

RESULTS

We reported our findings and compared our cases with the few others appearing in the literature. We documented an impaired neutrophil chemotaxis in 2 subjects, but neutrophil dysfunction does not seem to be one of the verifying criteria.

CONCLUSIONS

All of these cases may represent a distinctive form in the clinicopathological spectrum of neutrophilic dermatoses (ND) because of the typical distribution and the close link with different autoimmune disorders. Cimetidine in combination with ascorbic acid can be indicated as an effective and safe alternative to the classic medications of ND, although the action of both drugs remains unexplained.

IL-10 up-regulates human monocyte phagocytosis in the presence of IL-4 and IFN-gamma

Interleukin-10 (IL-10), a cytokine produced by type 2 helper T (Th2) cells, inhibits the microbicidal effector function of interferon-gamma (IFN-gamma)-activated macrophages. However, recent observations indicate that IL-10, like IFN-gamma, increases Fc gamma RI expression and Fc gamma R-mediated cytotoxic activity on human monocytes, suggesting that this cytokine cannot be classified purely as a monocyte deactivator. The present study found that incubation for 40 h of human monocytes or monocyte-derived macrophages in the presence of IL-10 caused a significant enhancement of their capacity to ingest particles coated with immunoglobulin G (Fc gamma R-mediated ingestion) or with C3b/C3bi fragments of the complement system (CR1/CR3-mediated ingestion). The number of phagocytosing cells (% phagocytosis) and the number of ingested particles per cell (phagocytic index) were both significantly higher after 40-h incubation of monocytes with IL-10 concentrations > or = 1 U/ml. This up-regulating activity on phagocytosis was completely reversed by anti-IL-10 monoclonal antibody (mAb). As previously reported, IL-10 stimulated Fc gamma RI expression on monocytes but did not induce the expression of Fc gamma RII, Fc gamma RIII, CR1, and CR3. IFN-gamma, like IL-10, up-regulated only Fc gamma RI expression but significantly reduced both Fc gamma R- and CR-mediated ingestion. IL-10 almost completely reversed the IFN-gamma-induced inhibition of both Fc gamma R- and CR-mediated phagocytosis, without concomitant changes in membrane expression of phagocytic receptors. Exposure of monocytes to IL-4 reduced the membrane expression of all three Fc gamma Rs and also inhibited Fc gamma R-mediated ingestion. On the other hand, IL-4 up-regulated both CR3 expression and CR-mediated ingestion on cultured monocytes. IL-10 not only neutralized the down-regulatory effect of IL-4 on Fc gamma R expression but also completely reversed the IL-4-induced suppression of Fc gamma R-mediated phagocytosis. Exposure of monocytes to a combination of IL-10 and IL-4 resulted in a synergistic effect on CR-mediated ingestion, even though no additive effects were observed on CR membrane expression. Finally, culture of monocytes in medium containing anti-IL-10 mAb significantly reduced their capacity to ingest IgG- or C3b/C3bi-coated particles, suggesting a role for endogenously produced IL-10 in the modulation of phagocytosis by human monocytes.(ABSTRACT TRUNCATED AT 400 WORDS)

Abnormal neutrophil chemotaxis in bone marrow transplant patients correlates with impaired 31D8 monoclonal antibody binding

BACKGROUND

31D8 monoclonal antibody (mAb) has been shown to bind heterogeneously to human neutrophils, identifying subsets of cells which differ in their functional response to chemotactic stimuli. In this study we used 31D8 mAb to determine whether differences in neutrophil subpopulations might explain the long-lasting decreased chemotaxis observed in bone marrow transplant recipients.

METHODS

Thirty patients with self-sustaining hematopoiesis 1 to 5 years bone marrow transplantation (BMT) (15 allogeneic and 15 autologous) performed for acute lymphocytic leukemia (ALL, 10 patients) or acute myelogenous leukemia in complete remission (8 patients), Hodgkin's lymphoma (2 patients), chronic myeloid leukemia (8 patients) and severe aplastic anemia (2 patients) were included in the study. Neutrophil chemotaxis was evaluated using a modified Boyden chamber assay and 31D8 binding was determined by indirect immunofluorescence and cytofluorimetric analysis.

RESULTS

Neutrophil chemotaxis was significantly impaired in the BMT group with respect to controls. The chemotactic defect strikingly correlated with autologous BMT and, in particular, with ALL as the pre-existing disease. No differences between patients and controls were observed in the percentage of 31D8 bright and dull neutrophils. However, when mean fluorescence intensity (MFI) was analyzed as a relative measure of 31D8 antigen expression on the overall neutrophil population, a significant decrease was observed in neutrophils from BMT patients with respect to controls. As for chemotaxis, the impairment of 31D8 binding was more evident in autologous BMT and strikingly correlated with ALL as the pre-existing disease regardless of age, sex and time since BMT. Moreover, a significant positive correlation between impaired chemotaxis and decreased 31D8 binding was found in our patients.

CONCLUSIONS

These findings suggest that the decreased neutrophil chemotaxis observed in some BMT patients may be due in part to circulating 31D8 dull neutrophils, although the causes for the decreased 31D8 binding and for the quite pronounced neutrophil defect in ALL patients remain unknown.

Fc receptors expression and function in mononuclear phagocytes from AIDS patients: modulation by IFN-gamma

Fc-receptor (FcR)-mediated phagocytosis and FcR (FcRI, FcRII and FcRIII) membrane expression was studied on freshly separated and cultured monocytes (Mo) from 20 AIDS patients and 20 healthy controls. Both Mo and Mo-derived macrophages from AIDS patients presented a significant defect in their capacity to ingest IgG-coated erythrocytes (EA) compared to control cells. This functional defect did not depend on a decline in the number of FcR+ cells or on a decrease in the expression of FcR on their surface. In fact, the percentages of phagocytes reacting with anti-FcRI MoAb (32.2) or anti-FcRII MoAb (IV.3) were similar for controls and AIDS patients, while the percentage of FcRIII-positive Mo (MoAb 3G8) was higher in the AIDS population than in controls, though this difference was not seen on cultured Mo. The level of FcRI expression, evaluated as mean fluorescence intensity (MFI), was higher on freshly separated Mo from AIDS patients than from controls but this difference disappeared also with differentiation of Mo to Mo-derived macrophages in vitro. Parallel analysis of FcRII and FcRIII on phagocytes revealed no differences in the MFI between the AIDS and control groups. Some observations suggested that this functional defect might be secondary to phagocyte priming by circulating IFN-gamma: (1) in vitro stimulation of Mo with hrIFN-gamma, which increased FcRI expression, actually reduced phagocytosis of IgG-coated particles; and (2) IFN-gamma concentrations were increased in AIDS patients' plasma. In spite of these findings, no significant correlation was found between plasma IFN-gamma concentrations and FcR-mediated ingestion in AIDS patients, making the hypothesis uncertain. Even if the basis for the impaired FcR-mediated phagocytosis in AIDS patients remains unclear, this functional defect may have a role in the immunopathogenesis of AIDS, constituting a component cause of the immunodeficiency.

Increased expression of IgG Fc receptor type I on neutrophils and monocytes from HIV-infected subjects

Interferon-gamma (IFN-gamma) induces de novo expression of IgG Fc receptor type I (FcRI) on neutrophils and significantly raises the level of these receptors on monocytes. Since increased concentrations of IFN-gamma have been observed in sera from patients with HIV infection, FcRI expression might also be increased on these subjects' phagocytes. FcRI expression was assessed by indirect immunofluorescence staining of phagocytes in whole blood from 40 healthy controls and 55 HIV+ subjects, 24 belonging to CDC class III and 31 to CDC class IV; 42 were intravenous drug abusers (IVDA) and 13 were homosexual men. Plasma levels of IFN-gamma were measured using a modified immunoradiometric assay. The mean linear fluorescence intensity, used as a relative measure of receptor expression, was significantly higher on unseparated neutrophils from HIV+ subjects in CDC classes III (P < 0.001) and IV (P < 0.0001) than from controls. Similar changes in FcRI expression were observed on monocytes from HIV+ subjects. While no differences were observed between IVDA and homosexual HIV+ patients, there was a significant association between FcRI expression and the patients' CDC stage, those in class IV having the highest FcRI levels. Plasma IFN-gamma concentrations were significantly higher in HIV+ patients than in controls and a positive correlation with the stages of HIV infection was again observed. FcRI expression was also increased on freshly purified neutrophils from five HIV+ patients in CDC class IV but did not increase further after 18 h incubation with IFN-gamma, a treatment that up-regulated FcRI expression on control neutrophils. These data suggest that: (i) FcRI evaluation may be a sensitive marker for the biological activity of IFN-gamma in vivo; (ii) phagocytes from HIV+ subjects are activated in vivo by IFN-gamma, expressing increased levels of FcRI; (iii) these IFN-gamma-activated cells may play a role in the pathogenesis of AIDS.

Membrane expression and function of complement receptors CR1 and CR3 on neutrophils from HIV-infected subjects: modulation by rTNF-alpha and rGM-CSF

We evaluated membrane expression and function of complement receptors CR1 and CR3 on neutrophils from 27 HIV-positive (HIV+) subjects (14 in the CDC class III and 13 class IV) as well as their modulation in vitro by recombinant tumour necrosis factor-alpha (rTNF-alpha) and granulocyte-macrophage colony stimulating factor (rGM-CSF). While CR1 was expressed at similar levels on neutrophils from controls and HIV+ subjects, CR3 expression was significantly higher in CDC class IV subjects than in healthy controls. CR1 and CR3 expression was significantly increased after treatment of neutrophils with both cytokines, without differences between controls and HIV+ subjects. Similarly, the superoxide anion (O2-) production in response to C3-coated zymosan (C3zy) was significantly enhanced on neutrophils from CDC class IV subjects when compared with controls. rGM-CSF and rTNF-alpha treatment significantly enhanced the spontaneous as well as C3zy-stimulated O2- production by neutrophils from controls and CDC class III subjects, and induced an upward trend in the CDC class IV group. These results indicate that the neutrophils of HIV+ patients are preactivated in vivo but they also indicate that these cells may correctly respond to a subsequent particulate stimulus as well as to activating cytokines. Our findings suggest that desensitization or functional exhaustion of complement receptors are not implicated in the abnormalities observed on neutrophils from HIV+ patients.

Monocyte-derived macrophage function in HIV-infected subjects: in vitro modulation by rIFN-gamma and rGM-CSF

We investigated monocyte-derived macrophage function in 25 HIV-positive patients, 19 in the CDC class III and 6 class IV; 17 were intravenous drug abusers (IVDA) and 8 were homosexual men. Macrophages from HIV-positive patients behaved normally in assays of superoxide anion (O2-) production and candidacidal activity. After 3 days' treatment with 200 U/ml recombinant interferon-gamma (rIFN-gamma) or 250 U/ml recombinant granulocyte/macrophage-colony stimulating factor (rGM-CSF), both control and HIV-positive patients' phagocytes expressed the activated state, as indicated by the increased O2- production in response to phagocytable or soluble stimuli; however, these cytokines did not enhance candidacidal activity. Compared to appropriate HIV-negative controls (18 healthy heterosexuals, 4 homosexuals and 4 IVDA), macrophages from 19 of the 25 HIV-positive patients presented a significant defect in their Fc receptor (FcR)-dependent phagocytosis, independently from the CDC stage, AZT therapy, or life style. Treatment of macrophages with rIFN-gamma impaired their capacity to ingest IgG-coated erythrocytes, both in controls and HIV-positive subjects. Treatment of phagocytes with rGM-CSF significantly increased their FcR-dependent phagocytosis in controls, whereas in HIV-positive patients and in HIV-negative homosexuals and IVDA only an upward tendency was observed. Although the mechanism of the impaired FcR-dependent phagocytosis in HIV-positive patients remain to be clarified, our results suggest that this functional defect may be secondary to phagocyte priming by circulating IFN-gamma in vivo. This macrophage alteration may be implicated in the immunodeficiency of HIV-positive patients. However, considering the potential role of FcRs in HIV infection enhancement, the defective FcR function might even be a protective mechanism against FcR-mediated HIV dissemination. In the light of these findings, the immunotherapeutic potential of IFN-gamma and GM-CSF in HIV infection merits further investigation.

Immunopharmacological activity of cefodizime in young and elderly subjects: in vitro and ex vivo studies

The biological response modifying activities of cefodizime (CDZ), a new third-generation cephalosporin, were investigated in vitro and ex vivo. In vitro investigations using cells isolated from the blood of young healthy donors showed no stimulating activity of CDZ on peripheral blood lymphocytes, natural killer cell activity, IL-1 production by adherent mononuclear cells, PMN chemiluminescence or PMN chemotaxis. A slight but statistically insignificant increase in PMN phagocytosis and phagocytic index was observed in the same population. IL-1 production was increased in three subjects with low resting state values. In a controlled ex vivo study, 20 healthy elderly subjects selected on the basis of depressed phagocytic function were treated with CDZ 1 g i.m. b.i.d. or placebo for eight days. PMN function was determined at baseline and on the day after the last dose. In the CDZ group a significant increase in both phagocytosis and phagocytic index was found, while there were no changes in the placebo group. In conclusion, CDZ restored depressed PMN phagocytic function in a population of elderly subjects. Patients with impaired PMN function who require antibiotic treatment may benefit from this activity of CDZ.

Immunostimulation of neutrophil phagocytic function by RU41740 (Biostim) in elderly subjects

On this randomized, double-blind trial we investigated the effect of RU41740, a glycoprotein extracted from Klebsiella pneumoniae, on human neutrophil function after oral administration to elderly subjects with a previously demonstrated phagocytic defect. Six subjects were given RU41740 orally at a daily dose of 2 mg for one week the first month and of 1 mg for one week the second month, while six subjects received placebo. Already after the first week of treatment with RU41740 (T1) and more evidently 3 weeks after the last administration of the first course of therapy (T2), a significant improvement of the neutrophil phagocytic capacity was observed; at the time T2, as well as at the end of the second course of therapy (T3), the phagocytic capacity was completely restored with no differences between control and aged subjects. Similar results were obtained in the chemiluminescence assays. As expected, placebo had no significant effect on neutrophil functions. No significant differences were observed between the two group of elderly subjects for total or differential leukocyte number. These results suggest that RU41740 exerts, almost in part, its clinical effect, i.e. the prevention of recurrent infections, by stimulating blood neutrophil phagocytic function.

The effect of cytokines on human neutrophil Fc receptor-mediated phagocytosis

The recombinant (r) cytokines interferon-gamma (rIFN-gamma), granulocyte/macrophage-colony stimulating factor (rGM-CSF) and tumor necrosis factor-alpha (rTNF-alpha) all activate neutrophils. The aim of this work was to determine the effect of these cytokines on neutrophil Fc-receptor (FcR)-mediated phagocytosis and membrane expression of FcR, particularly FcRII and FcRIII. A short treatment (greater than or equal to 15 min) of neutrophils with rGM-CSF and rTNF-alpha at concentrations greater than or equal to 62.5 U/ml significantly increased their ability to bind and phagocytize IgG-coated erythrocytes (EA). Both cytokines also showed more enhancing activity when suboptimally sensitized EA were used for binding and ingestion assays. A similar treatment of neutrophils with rIFN-gamma at doses up to 500 U/ml was ineffective. The effect of rGM-CSF and rTNF-alpha was blocked by a monoclonal anti-GM-CSF antibody and by a polyclonal anti-TNF-alpha antibody respectively, thus establishing that the cytokines were responsible for the activity of the recombinant preparations. The cytokine-induced enhancement of FcR-mediated phagocytosis did not correlate with an enhancement of FcRII membrane expression on treated neutrophils; rGM-CSF significantly increased FcRIII expression, but rTNF-alpha and rIFN-gamma were both ineffective in this respect. Since different roles of FcRII and FcRIII have been reported on ligand binding and ingestion, we also studied the effect of rGM-CSF and rTNF-alpha on the functional properties of these FcR, using specific monoclonal antibodies (mAbs). In the blocking experiments the pretreatment of neutrophils with rGM-CSF and rTNF-alpha did not modify the blocking properties of either anti-FcRII or anti-FcRIII mAbs, suggesting that cytokine-pretreatment does not affect the individual contribution of each type of FcR to ligand binding and internalization. Our data point to a new activity for both rGM-CSF and rTNF-alpha in augmenting FcR-mediated phagocytosis on neutrophils, but the mechanism of this enhancement remains to be elucidated.

Increased expression of C3b and C3bi receptors on human neutrophils and monocytes induced by a glycoprotein extract from Klebsiella pneumoniae (RU41740)

RU41740 is a glycoprotein extract from Klebsiella pneumoniae with immunomodulating properties under different experimental conditions. In particular the compound is able to stimulate several functions of human phagocytes in vitro and ex vivo. Using monoclonal antibodies and flow cytometry, in this work we assessed the effect of RU41740 on surface expression of receptors for C3b (CR1) and C3bi (CR3) in human phagocytic cells in vitro. The incubation of whole blood with varying RU41740 concentrations led to a dose-dependent increase in surface expression of CR1 and CR3 on both neutrophils and monocytes when compared with control samples incubated in buffer alone. The maximal drug-induced enhancement of complement receptors was: 291% +/- 13.4% for CR1 and 265% +/- 8.5% for CR3 in neutrophils; 117% +/- 4.5% for CR1 and 98% +/- 4.1% for CR3 in monocytes. These peak effects were observed using RU41740 at a final concentration of 10 micrograms/ml and were similar to those induced by optimal concentrations of the activating compound N-formyl-methionyl-leucyl-phenylalanine (10(-7)M). Polymyxin B did not modify the RU41740-induced enhancement of CR1 and CR3 expression on phagocytes, suggesting no role for endotoxin in this activity. These results define, at least in part, the mechanism of action of RU41740 on human phagocytes in vitro and could be relevant to in vivo events during RU41740 treatment.

Clinical and laboratory findings in a new case of leukocyte adhesion deficiency

We describe a child suffering from recurrent bacterial infections whose cells exhibited laboratory findings compatible with the leukocyte adhesion deficiency (LAD) syndrome. Surface marker analysis with monoclonal antibodies (MAbs) to the individual alpha and beta chains of LFA-1/Mac-1/p150,95 antigens revealed that the patient's neutrophils did not express the common beta chain and LFA-1/p150,95 alpha subunits, but reacted weakly with four different MAbs specific for the Mac-1 alpha chain; however, no glycoprotein was immunoprecipitated from the patient's cells using the same anti-Mac-1 alpha MAbs. Functional analysis of the patient's phagocytes revealed many of the defects in adherence-dependent functions (adherence, chemotaxis and phagocytosis) described in patients with LAD. The studies performed on the phagocytes of the patient's relatives showed normal phenotypes and function, suggesting the possibility of a non heritable form of disease in this family.

A new simplified single-filter assay for 'in vitro' evaluation of chemotaxis of 51Cr-labeled polymorphonuclear leukocytes

A new simplified radioassay for measuring polymorphonuclear leukocyte (PMN) chemotaxis is proposed using 51Cr-labeled cells and a single-filter system. The technique offers all the advantages described for the double-filter radioassay and permits a reproducible measurement of random locomotion, chemokinesis and chemotaxis. Moreover the single-filter radioassay utilizes commercially available and disposable chambers gathered in a multichamber apparatus; this makes the method very easy to learn and rapid to perform.

Bone marrow and tissue expression of gpIIb/IIIa, LFA-1, Mac-1 and gp150,95 glycoproteins

Monoclonal antibodies (MAbs) against platelet glycoprotein gpIIb/IIIa and the leucocyte adhesion molecules LFA-1, Mac-1, and gp 150,95 alpha chain (CD11a,b,c) and beta chain (CD18) have been tested in normal and leukaemic bone marrows, in different human tissues, and in a patient with leucocyte adhesion deficiency (LAD). The effect of these MAbs on platelet aggregation was also tested. GpIIb/IIIa showed widespread distribution, while reactivity of CD11/18 antibodies was limited to haematopoietic cells. Platelets and megakaryocytes were reactive with one CD11a (25.5.2), and with no CD11b/c or CD18 MAbs. GpIIb/IIIa was present on the platelets of the patient with LAD, whereas 25.5.2, (CD11a) bound to his platelets but not to his leucocytes. These data indicate that LFA-1, Mac-1, and gp150,95 are not present on human platelets, but they suggest the existence of crossreacting epitopes on gpIIb/IIIa, which is consistent with the hypothesis that these molecules belong to a supergene family of adhesion molecules.

In vitro modulation of human monocytes functions by RU 41740 (Biostim)

The in vitro effects of RU 41740, a mixture of two glycoproteins extracted from K. pneumoniae and possessing immunomodulatory activity, on human monocyte's cytotoxic activity, migratory capacity and monokine production were investigated. Exposure to RU 41740 in nanogram concentrations was associated with rapid increases in IL-1 and TNF production and marked augmentation in the monocytes' killing of TNF-sensitive targets, whereas killing of TNF-insensitive targets required longer exposures to microgram concentrations of this drug. Using otherwise effective treatment conditions, RU 41740 did not directly affect monocyte's spontaneous and FMLP-induced migration. The possible role of mononuclear cells stimulation and increased production of effector and regulatory monokines in the immunomodulatory activity of this product is addressed.

In vitro and ex vivo effect of RU41740 on human polymorphonuclear leukocyte function

We investigated the effect of RU41740, a glycoprotein extracted from Klebsiella pneumoniae and possessing immunomodulating properties, on human neutrophil functions in vitro and ex vivo. Our in vitro results showed that RU41740 increased complement- and Fc receptor-dependent phagocytosis. Moreover, the drug enhanced the oxidative metabolism (assessed by chemiluminescence) both in resting and stimulated cells; in the latter case the RU41740-induced enhancement was observed when neutrophils were stimulated with opsonized particles of N-formyl-methionyl-leucyl-phenylalanine (FMLP) but not when phorbol myristate acetate was used. Using otherwise effective experimental conditions, RU41740 did not affect spontaneous or FMLP-induced neutrophil migration. For the ex vivo experience we tested neutrophils of ten elderly subjects with a previously demonstrated phagocytic defect. These subjects were treated orally with RU41740 at a daily dose of 2 mg for 1 week during the first month, and of 1 mg for 1 week in the second month. In this population, RU41740 was able to restore the impaired phagocytic activity and to induce a significant increase of spontaneous chemiluminescence (CL); stimulated CL was also positively influenced. These effects on neutrophils provide new explanatory bases for the immunostimulatory activity of RU41740.

Inhibition of neutrophil oxidative metabolism by nimesulide

Oxygen derived free radical release from activated neutrophils may be in part responsible of tissue damage in the acute phase of inflammation. We have shown that the methane sulfonanilide antiinflammatory agent nimesulide inhibits the respiratory burst of phagocytosing neutrophils without affecting their phagocytic or chemotactic responsiveness. In fact, chemiluminescence and superoxide anion generation by polymorphonuclear leukocytes (PMN) stimulated with zymosan particles or with the synthetic peptide FMLP are inhibited by nimesulide and its 4-OH metabolite in a dose dependent fashion without affecting cell viability. The control of the extracellular flux of radical species by pharmacological compounds may affect the course of inflammation reducing tissue damage. Our data suggest that the inhibition of superoxide anion production by neutrophils is an additional mechanism of action of the antiinflammatory agent nimesulide.

Immunomodulating activity of RU 41740: in vitro and in vivo studies on human lymphocytes

A group of institutionalized elderly subjects, selected on the basis of their skin hypoergy and displaying different kinds of T and B lymphocyte impairments has been chosen as a model to verify the in vivo immunopotentiating activity of RU 41740 on human lymphocytes. Oral treatment with the drug was able to: restore or improve the cutaneous delayed hypersensitivity to recall antigens; significantly increase the blastigenetic response to mitogenic and submitogenic doses of PHA and PWM and improve the in vitro PWM-induced synthesis of IgG and IgM. The immunopharmacological activity of RU 41740 appeared to persist three months after the end of therapy, without any direct stimulating activity on the peripheral blood lymphocytes. The in vitro results seem to suggest that peripheral lymphocytes are not directly influenced by the drug.

Defective granulocyte chemotaxis and natural killer activity in a patient with recurrent infections

A 25-year-old male with a history of recurrent infections presented with fever, severe aplastic anaemia, splenomegaly and retroperitoneal node enlargement. Lympho-histiocytic granulomas were found in spleen, liver and lymph nodes. Granulocyte studies revealed normal morphology, severely impaired random migration and complete absence of directed locomotion. Whereas phagocytosis was slightly reduced, candidacidal activity and nitroblue tetrazolium reduction were normal. Basal granulocyte cyclic GMP levels were within the normal range while a 5-fold increase of cyclic AMP levels was observed. Numerous abnormalities were also found in the patient's lymphocytes: lack of delayed hypersensitivity, reduced response to mitogens, low OKT4/OKT8 ratio, absence of natural killer (NK) activity with normal number of cells recognized by NK-specific monoclonal antibodies. These observations describe a distinct clinico-pathologic entity and suggest the possibility of a common defect in granulocytes and in NK cells.

Chronic granulomatous disease in a 23-year-old female

A 23-year-old girl with clinical and laboratory findings characteristic of chronic granulomatous disease is described. The patient was admitted to hospital because of severe disseminated aspergillosis. Studies of neutrophils showed normal phagocytosis but impaired microbicidal killing and a failure of the respiratory burst activity as measured by NBT-reduction, superoxide generation, chemiluminescence and antibody-dependent cell mediated cytotoxicity. Patient's neutrophils had normal chemotactic responsiveness but a marked impairment in the level of serum chemotactic activity was observed. Neutrophils from the parents and 2 maternal aunts showed normal values for all the determinations. The lack of evidence for a carrier state in all the family members studied together with the inability to detect a mixed population of neutrophils in our patient are in contrast with the Lyon's hypothesis of X-chromosome inactivation. Our findings suggest an autosomal recessive inheritance in this female with chronic granulomatous disease.

Neutrophil chemotactic factor of anaphylaxis (NCF-A) release in aspirin-induced asthma

Neutrophil chemotactic activity (NCA) following oral challenge with aspirin (ASA) was determined in ASA-intolerant asthmatic subjects, and in ASA-tolerant asthmatic and normal subjects. There was a statistically significant fall in FEV1 and a rise in NCA (P less than 0.01) following challenge in the ASA-sensitive subjects compared with that of the ASA-tolerant subjects and normal controls. No significant difference was observed between the latter two groups. The chemotactic factor identified in this study had a molecular weight greater than 150 000 which is consistent with NCF-A (neutrophil chemotactic factor of anaphylaxis). The ASA-induced fall in FEV1 and rise in NCA was further studied in three of the ASA-intolerant asthmatic subjects, with and without pretreatment with inhaled sodium cromoglycate. In these subjects, the drug inhibited both the oral ASA-induced bronchoconstriction and the increase in neutrophil chemotactic activity. These results suggest that ASA-induced asthma involves mediator release from mast cells, as shown by the increase in NCA following ASA challenge and the protective effect of sodium cromoglycate which is considered to inhibit mast-cell degranulation.

Effect of corticosteroids on neutrophil function: inhibition of antibody-dependent cell mediated cytotoxicity (ADCC)

Hydrocortisone sodium succinate (HC) inhibited "in vitro" neutrophil-mediated antibody-dependent cellular cytotoxicity (ADCC). The drug effect was dose-dependent and completely reversible. The killing defect was partially overcome by increasing the density of the antibody on the target cells. However, HC added after the binding between effector and target cells was still able to inhibit in a similar dose-dependent way the cytotoxic activity. Our results suggest that HC interferes in a later step, after the effector/target interaction. Methyl-prednisolone and dexamethasone as well as HC were found to inhibit in a dose-dependent manner the neutrophil-mediated ADCC, whereas testosterone did not have any effect.

Defective suppressor cell activity in essential mixed cryoglobulinemia

Peripheral blood mononuclear cells from patients with essential mixed cryoglobulinemia were investigated for the ability to induce suppressor cell activity (S.C.A.) following in vitro exposure to Concanavalin A (Con A). The generation of Con A-S.C.A. is significantly impaired in essential mixed cryoglobulinemia compared to the healthy controls. No correlation was found between Con A-S.C.A. and the clinical or laboratory parameters of the disease. This impaired ability to induce Con A-S.C.A. in essential mixed cryoglobulinemia reflects a functional T-cell defect, which may play a role in the pathogenesis of the disease.

Inhibition of polymorphonuclear leukocyte-mediated cytotoxicity by hydrocortisone "in vitro"

The effect of hydrocortisone (HC) on in vitro human polymorphonuclear leukocyte cytotoxicity was studied. HC was able to inhibit reversibly and in a dose-dependent way the antibody-dependent cellular cytotoxicity (ADCC) and the phytohemagglutinin-dependent cellular cytotoxicity (PDCC). The killing defect was partially overcome by increasing the antibody or the phytohemagglutinin (PHA) concentrations on the target cells. HC inhibited the PDCC more efficiently than ADCC; in fact the inhibition was present even at 10-5 M HC levels. Higher concentrations caused a progressive reduction in both tests. Inhibition of these PMN-mediated cytotoxicities may explain, in part, bot the anti-inflammatory actions of steroids and their deleterious effects on host defenses.