Is chemotactic activity of polymorphonuclear leukocytes increased in psoriasis?

Natural killer cell activity, serum immunoglobulins, complement proteins, and zinc levels in patients with psoriasis vulgaris

The role of the immune system in patients with psoriasis vulgaris (PV) was investigated. The genetic and immunological basis for psoriasis is still unknown. Because of the reports of immunological defects in this disease, we investigated serum levels of immunoglobulins IgG, IgM, IgA, complement proteins C3, C4, serum zinc (Zn) levels and natural killer (NK) cell activities. Skin lesions of the psoriatic patients involved in the study comprised less than 10 % of the total body and the disease was in a stationary period. Zn levels were measured by atomic absorption spectrophotometry. NK cell activity was measured by 51Cr (Na2 51CrO4). IgG, IgA, IgM, C3 and C4 assays were done by liquid-phase immunoprecipitation assay with nephelometric endpoint detection. IgG, IgA, C3 and C4 levels were significanty higher in patients with PV than in healty controls (p < 0.05). However, NK cell activity, serum Zn and IgM levels did not show significant differences between these two groups. There are changed immunological responses, which may play an important role in the pathogenesis of the disease. Many controversial results have been related to immunological parameters in psoriatic patients. Therefore, more detailed studies in this field need to be done to determine the relationship between psoriasis and the immune system.

Etretinate or cyclosporin-A treatment normalizes the enhanced respiratory burst of polymorphonuclear leukocytes in psoriasis

During a therapeutic trial to treat psoriasis with either etretinate or cyclosporin A (CyA) we measured the respiratory burst activity of polymorphonuclear leukocytes (PMN). Six patients received 0.5-0.75 mg/kg etretinate and 14 patients 2.5-5.0 mg/kg CyA over a period of 10 weeks. The extent of psoriasis was graded by the psoriasis area-and-severity index (PASI score). The respiratory burst of PMN isolated from the peripheral blood was measured employing luminol-enhanced chemiluminescence at weeks 0, 3 and 10 and compared with that of 26 healthy control individuals. PMN were stimulated with zymosan particles, aggregated immunoglobulin (aggIg) and concanavalin A (ConA). Both treatment regimens improved psoriasis; at 10 weeks there was an approximate 40% PASI score reduction under etretinate and an 80% improvement under CyA. Before treatment the respiratory burst was abnormally high under stimulation with the three stimuli in patients (p = 0.021 to less than 0.0001). After 3 to 10 weeks PMN activity normalized in all patients and even tended to drop below values correlating with an improvement in skin lesions. We conclude that the elevated respiratory burst of PMN in psoriasis normalizes under treatment with both etretinate and CyA.

Studies of polymorphonuclear migration into psoriatic skin using a new in vivo method

A new method, employing a skin-implanted cell trap already used to study chemotaxis in cancer patients, was applied to 35 healthy volunteers and 12 psoriatic patients. A dacron disk impregnated with 10 microliters of 4-6.10(6) live BCG suspension was implanted in the deep dermis. After 24 h the disk was removed, and five sections of each disk were counted for polymorphonuclear leukocytes (PMNs) and monocytes. Involved and uninvolved psoriatic skin showed a decrease of PMN migration into the disk as compared with controls. No difference could be demonstrated between involved and uninvolved skin. Mononuclear cell chemotaxis was the same in psoriasis as in controls. These results are in agreement with other in vivo data using mainly the skin chamber technique indicating a decrease of PMN chemotaxis in psoriatic skin at 24 h.

Reduced expression of surface receptors for synthetic N-formylated chemotactic oligopeptides by stimulated peripheral blood neutrophils in psoriasis

Receptors for synthetic N-formylated chemotactic peptides on peripheral blood neutrophils were studied by the binding of fluorescein-labeled hexapeptide (N-formyl-Nle-Leu-Phe-Nle-Tyr-Lys) to the cells in vitro at the range of concentrations 0.01-100 nM. Mean fluorescence of neutrophils was quantitated by a flow cytometry using FACS III. Comparison was made between 27 patients with psoriasis vulgaris and 14 normal controls. Various receptor states related to cell activities were induced by different temperatures, by incubation of cells with cytochalasin B and by preincubation with nonlabeled N-formyl-Met-Leu-Phe. This allowed us to distinguish between the specific binding of fluoresceinated hexapeptide to plasma membrane receptor already present (0 degree C), modulation of receptors by peptide and cytochalasin B stimulated degranulation (25 degrees C), and net binding, including internalization of peptide and receptor recycling system (37 degrees C). At peptide concentrations of 1-10 nM, the labeling of neutrophils at 25 degrees C and 37 degrees C, but not at 0 degree C, was found to be about 10-35% lower in psoriatic than in healthy subjects (p less than 0.002). The amount of fluorescein-labeled peptide bound to the cells at 25 degrees C was markedly increased by cytochalasin B, but to a much lower extent in psoriatic patients than in normal controls. Although the number of plasma membrane receptor for chemotactic peptides in the nonstimulated neutrophils was not altered in psoriasis, the receptor up-regulation induced by preincubation of the cells with 1-10 nM of nonlabeled N-formyl-Met-Leu-Phe at 37 degrees C was reduced when measured by subsequent fluoresceinated hexapeptide uptake at 0 degree C. Receptor recycling, as measured by an increase with time (0-30 min) in the binding of chemotactic peptide by neutrophils in which receptors had been down-regulated, was found to be within normal range in patients with psoriasis. These data indicate that nonstimulated, circulating neutrophils have a normal number of chemotactic peptide receptors on the cell surface, but are less able to recruit intracellular receptors to the cell surface. This finding may be related to smaller internal pools or less efficient translocation of these receptors.

Electron microscopic features in generalized pustular psoriasis

Basal keratinocyte herniations (BKH) have been used as markers of psoriatic activity. Abnormal multipolypoid forms herniating through large gaps in the basal lamina have been found to characterize biopsies from psoriatic patients with concomitant alpha 1-antitrypsin deficiency, and appear to be a marker of excessive proteolytic activity. The finding of similar multipolypoid BKH in patients with generalized pustular psoriasis of the von Zumbusch variety (but not in patients with psoriasis vulgaris), in the absence of concomitant alpha 1-antitrypsin deficiency, would support the concept of the presence of large amounts of proteolytic enzymes in the dermis of patients with this syndrome. The large proportion of BKH directly associated with dermal neutrophils, and the presence of clusters of high-density BKH overlying collections of dermal neutrophils, suggests that neutrophilic proteases are largely responsible for BKH formation in patients with this syndrome.

Neutrophil locomotion and serum chemotactic and chemokinetic activities in pustulosis palmoplantaris compared with psoriasis

Twenty patients with palmoplantar pustulosis (PPP) and 21 patients with psoriasis were compared with respect to the chemotactic response and random migration of their neutrophils (PMNs) and to the chemotactic and chemokinetic activities of their serum. The Boyden chamber technique was used. Compared with the reference group, the PPP neutrophils showed a significant decrease in random migration (p = 0.036) and chemotactic response to casein (p = 0.031), but not to zymosan-activated serum. The psoriasis PMNs had normal chemotactic response, but decreased random migration (p = 0.001). The chemokinetic effects of serum from PPP and psoriatic patients on normal neutrophils were increased (for PPP, p = 0.019 and for psoriasis p = 0.024). The chemokinetic activity of the heated sera was decreased and inversely correlated to the serum level of IgA in both disorders (PPP, p = 0.021; psoriasis, p = 0.013). The chemotactic activity of serum on normal PMNs was decreased in both conditions (PPP, p = 0.001; psoriasis, p = 0.047); this was due to the presence of chemotactic factor inhibitors in 34% of the sera. It seems likely that the high chemokinetic effect of serum both from the PPP and from the psoriasis patients compensates for the slightly low or normal migratory activity of neutrophils from these patients.

Methotrexate inhibits the human C5a-induced skin response in patients with psoriasis

In this study we examined the effects of intradermal injections of human complement split product C5a in 10 patients with psoriasis in long-term treatment with methotrexate (MTX). The C5a was injected at the end of the weekly MTX cycle just before the intake of the first MTX dose and 3 h after the second of the 3 doses. The C5a-induced skin response was evaluated by measuring the diameter of the wheal and the area of the flare and by erythema index (EI), which was determined objectively by reflectance spectrophotometry. In all patients the skin response was significantly depressed when C5a was injected after MTX intake. The decrease of wheal, flare, and EI averaged 61.6%, 71.1%, and 57.5%, respectively, when all parameters were obtained at maximal skin response. The in vitro chemotaxis of peripheral blood neutrophils and monocytes from the patients toward C5a was markedly inhibited after intake of MTX (p less than 0.01). The skin biopsies obtained after C5a injection before intake of MTX revealed a perivascular inflammatory infiltrate and considerable dermal edema. After MTX intake the number of infiltrating leukocytes and the degree of dermal edema was markedly reduced. This study indicates that MTX is a potent inhibitor of C5a-induced skin inflammation, and that this inhibition may be caused by a direct effect on circulating neutrophils and monocytes. The results obtained in this work support the idea that anti-inflammatory effects of MTX may be partially responsible for its antipsoriatic effect.

The enhanced monocyte and neutrophil chemotaxis in psoriasis is normalized after treatment with psoralens plus ultraviolet A and anthralin

The chemotactic activity of purified monocytes and neutrophils was studied in twenty-two psoriatic patients prior to the initiation of psoralens plus ultraviolet A (PUVA) or anthralin therapy and during the treatment. Patients with untreated, active psoriasis had increased chemotactic response of their monocytes and neutrophils to N-formyl-methionyl-leucyl-phenylalanine. Plasma from untreated psoriasis patients had an enhanced chemotactic activity toward neutrophils from persons without psoriasis. Treatment with PUVA or anthralin resulted in a progressive clearing of psoriatic lesions and in a significant depression of leukocyte chemotaxis 2 weeks after the start of the respective therapy. The chemotactic activity of both monocytes and neutrophils was normalized after 4 weeks of anthralin therapy and after 6 weeks of PUVA treatment. The chemotaxis-enhancing properties of plasma from psoriasis patients returned to normal values already after 2 weeks of treatment.

Monocyte and neutrophil chemotaxis in psoriasis. Relation to the clinical status and the type of psoriasis

Chemotactic activity of purified monocytes and polymorphonuclear leukocytes was studied in fifty patients with psoriasis vulgaris and in forty-five healthy individuals by an objective in vitro assay with the use of a 51Cr-labeling technic. Both monocytes and polymorphonuclear leukocytes showed a statistically significant increase in chemotactic response, which was positively correlated with disease activity but not with the extent of the cutaneous lesions. The chemotactic activity of monocytes correlated with that of polymorphonuclear leukocytes in the same patients. Exacerbation of psoriasis was preceded by a rapid increase of polymorphonuclear leukocyte chemotaxis, and a decline of chemotaxis occurred during clinical improvement. The psoriatic leukocytes were 22% more sensitive than normal leukocytes to leukotriene B4 than to N-formyl-methionyl-leucyl-phenylalanine. Psoriatic plasma showed chemotaxis-enhancing properties, but only in patients with widespread cutaneous lesions. Additionally, monocyte and polymorphonuclear leukocyte chemotaxis was studied in twenty patients with pustular psoriasis and in fifteen patients with psoriatic arthritis. The chemotactic profiles in pustular psoriasis were different from those in psoriasis vulgaris. Patients with pustular psoriasis had significantly higher polymorphonuclear leukocyte chemotaxis than patients with psoriasis vulgaris, but the chemotactic activity of monocytes was normal. The presence of seronegative arthritis had no influence on chemotactic activity of psoriatic leukocytes.

Defective natural-killer- and killer-cell activity associated with increased polymorphonuclear leukocyte adherence in psoriasis

Patients (n = 45) with psoriasis vulgaris were studied for natural killer (NK) cell activity and antibody-dependent cell cytotoxicity (ADCC) of their peripheral blood mononuclear cells against K-562 and L1210 target cells, respectively. Simultaneously, the studies were performed on the adherence to human endothelium of polymorphonuclear leukocytes (PMN) from various forms of the disease. Mean values of NK-cell activity in psoriasis vulgaris, as a whole, and mean values of ADCC in male patients were significantly lower than in a group of healthy controls. This decrease was most pronounced in patients with the active form of the disease, in whom in vitro PMN adherence to human endothelium was found to be increased. Neutrophils from both patients with active psoriasis and healthy individuals were capable of reducing NK-cell activity of normal human mononuclear cells.

Decreased extracellular release of granule enzymes from in vitro-stimulated polymorphonuclear leukocytes in guttate psoriasis

In vitro degranulation of polymorphonuclear leukocytes, which were stimulated either with synthetic chemotactic peptide (N-formyl-methionyl-leucyl-phenylalanine, FMLP) or with C3b-opsonized zymosan as a promotor of phagocytosis, was studied in 66 patients with psoriasis, 18 lesion-free psoriatics, 18 healthy subjects, and 14 other dermatological disorder controls. Stimulated release of lysozyme (from specific granules and azurophil granules) and beta-glucuronidase (from azurophil granules) in the presence of both FMLP and serum-activated zymosan was markedly reduced in patients with actively spreading guttate psoriatic lesions, in whom relapse of lesions lasted for less than 1 month and papules involved about 13-25% of skin surface. In contrast, stimulated degranulation was within normal range in active plaque psoriasis, stationary plaque psoriasis, symptomless psoriatics, and patients with disseminated eczema. Spontaneous release of lysozyme and beta-glucuronidase (background) was found to be not different in all groups studied; however, patients with active guttate psoriasis had significantly lower total lysozyme activity than those with active and stationary plaque psoriasis as well as psoriatics in the remission. These data are in favor of in vivo activation of neutrophils in active guttate psoriasis by some factors related to the early relapse of the lesions. This results in a possible combination of the following phenomena: (1) in vivo partial degranulation of neutrophils; (2) induction of "unresponsiveness state" of these cells to subsequent in vitro stimulation; and/or (3) migration of highly responsive neutrophils to skin lesions, which leaves in the circulation the subpopulation less reactive to chemotactic and phagocytic stimuli.

Neutrophil and monocyte chemotaxis in pustulosis palmo-plantaris and pustular psoriasis

Polymorphonuclear leukocyte (PMN) and monocyte (MN) chemotaxis in nine patients with pustulosis palmo-plantaris (PPP) and ten patients with pustular psoriasis (PP) was determined by an objective in vitro assay employing a 51Cr-labelling technique. PMN chemotaxis was significantly enhanced in both groups of patients compared with controls. MN chemotaxis was normal. There was no difference in the chemotactic responsiveness of leukocytes from patients with PPP and PP. The random migration of PMN and MN from the patients was normal. Homogenized tissue specimens from lesional skin with and without pustules, and from perilesional, normal-looking skin of PPP and PP were analysed for the presence of chemoattractant(s) for PMN. Lesional skin had considerable chemoattractant properties, but perilesional skin did not induce directed migration of PMNs.

The adherence to human endothelium and plastic of neutrophils from psoriatic patients, and the effects of psoriatic patients' sera on normal neutrophils

Circulating polymorphonuclear neutrophils (PMNs) from 50 patients with psoriasis vulgaris and from 38 control individuals (28 healthy blood donors and 10 patients with systemic sclerosis) were tested for their ability to adhere to human endothelial cell monolayer and a plastic surface. We also studied the effect of sera from psoriatic patients on the adherence and chemotactic activity of normal human neutrophils. The neutrophils from patients with psoriasis were much more adherent to the endothelium and the plastic surface, and this correlated positively with the activity of the disease, but inversely with the extent of the skin lesion. The sera from patients with active psoriasis were found to enhance the adherence and chemotaxis of normal human PMNs. Treatment of the sera by heat (56 degrees C for 30 min) did not affect their enhancing effect on the adherence but significantly decreased their effect on the chemotactic activity of normal PMNs.

Stimulus-dependent increased generation of oxygen intermediates in monocytes and polymorphonuclear leukocytes in psoriasis

Based on recent findings indicating increased respiratory burst activity of monocytes (M phi) and polymorphonuclear leukocytes (PMN) in psoriasis upon stimulation with zymosan particles, we examined the question of whether incubation with various stimuli always results in augmented oxidative metabolism in psoriatic phagocytes. We compared M phi and PMN isolated from the peripheral blood of 12 patients with psoriasis and 12 control individuals. We measured the generation of oxygen intermediates of resting and stimulated M phi and PMN by luminol-enhanced chemiluminescence. The stimulants applied were: (1) aggregated immunoglobulin (aggIg), (2) zymosan, (3) zymosan opsonized with autologous serum, (4) phorbol myristate acetate (PMA), and (5) concanavalin A (ConA). We found no difference between patients and controls in the generation of oxygen intermediates by resting M phi and PMN. Stimulation by aggIg and zymosan yielded an increased chemiluminescent response in psoriatic M phi and PMN. Serum-treated zymosan effected increased light generation in M phi but not in PMN of patients. By contrast, PMA, and in particular ConA, brought about markedly increased generation of oxygen intermediates in PMN only of patients with psoriasis. Our results indicate control of the increased generation of oxygen intermediates of M phi and PMN by different stimuli. The metabolic events underlying the augmented phagocytic response may be similar to abnormalities found in involved psoriatic skin.