In vivo mobilization of polymorphonuclear leukocytes in psoriasis: relationship to clinical parameters and serum inhibitory factors

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.

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.

The chemokinetic response of psoriatic and normal polymorphonuclear leukocytes to arachidonic acid lipoxygenase products

Polymorphonuclear leukocytes (PMN) from ten patients with chronic stable plaque psoriasis, five of whom had more than 40% skin involvement and five with less than 20% involvement, responded in a dose-related fashion to stimulation with the arachidonic acid lipoxygenase products 5- and 12-hydroxyeicosatetraenoic acid (5- and 12-HETE) and leukotriene B4 (LTB4) in an in vitro chemokinesis assay. There was no significant difference in either the random migration or the chemokinetic response of psoriatic PMN to LTB4 when compared to the responses of PMN from a group of age- and sex-matched healthy controls. Psoriatic PMN migrated further in response to low doses of 5- and 12-HETE although the distance moved after maximal stimulation was no different to that observed in controls. No significant difference was observed in the responses of PMN obtained from patients with less than 20% skin involvement when compared to those with more extensive psoriasis. The small differences measured between the chemokinetic responses of psoriatic and control PMN to the lipoxygenase products tested are unlikely to be of pathogenetic significance.

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.

The responses of normal and psoriatic skin to single and multiple topical applications of leukotriene B4

Topical application of single doses of leukotriene B4, (5-500 ng) under occlusion to the skin of normal volunteers and to the clinically normal skin of patients with untreated stable plaque psoriasis caused an inflammatory reaction lasting several days. Histologically, intraepidermal neutrophil microabscesses were seen in both groups following 50 ng applications of leukotriene B4, but there were significantly fewer intraepidermal neutrophils in the psoriatic than in the normal subjects. Nine repeated daily applications of leukotriene B4 (50 ng) to the same site were associated with a reduction of the visible inflammatory response in both volunteer groups, although application of a single 50 ng dose of leukotriene B4 to an adjacent, previously untreated site at the end of the multiple dose experiments elicited acute erythema and edema. Histologically, there were significantly fewer intraepidermal neutrophils in biopsies from sites to which 9 applications of leukotriene B4 were made than in sites to which 1 dose had been applied at the end of the multiple-dose experiments in both psoriatic and normal volunteers. Therefore, repeated application of leukotriene B4 is associated with decreased responsiveness which is due to a local mechanism in the repeatedly treated skin. No subject developed psoriasis following single or multiple applications of leukotriene B4, suggesting that the production of leukotriene B4 in the epidermis is unlikely to be a primary pathogenic event in this disease.

Circadian rhythm of the in vivo migration of neutrophils in psoriatic patients

Neutrophil chemotaxis in ten subjects with psoriasis was evaluated in vivo by the quantitative skin-window technique using autologous serum and in vitro using a modified Boyden technique. The in vitro chemotaxis values of the psoriatics were significantly lower (P less than 0.01) than those of healthy controls. When measured in vivo, however, we found that, after 9, 12, and 24 h, the values of the migrating polymorphonuclear leukocytes (PMNL) of psoriasis patients were only slightly and non-significantly lower than normal values. Analysing the in vivo chemotaxis data by a chronobiological method, we demonstrated statistically significant circadian rhythms in nine of the ten psoriasis patients. In seven of the patients, we found that the population had a significant rhythm, with the acrophase at -328 degrees. Our in vitro and in vivo values are in agreement with previously published values. However, there was a definite circadian rhythm of migration that we could not demonstrate in normal controls. We consider that our data reveal a significant and important difference between neutrophil chemotaxis in vivo in normal subjects and that in patients with psoriasis.

Neutral proteinases and other neutrophil enzymes in psoriasis, and their relation to disease activity

The activities of elastase, cathepsin G, lysozyme and myeloperoxidase of polymorphonuclear leukocytes were determined by spectrophotometry in thirty-six patients with psoriatic lesions, twelve symptom-free patients with psoriasis and fifteen normal controls. The mean activities of cathepsin G, elastase and lysozyme were found to be increased by 55 to 70% in patients with actively spreading plaque lesions compared with healthy controls (P less than 0.01). Most patients with guttate lesions had total enzyme activities within the normal range. Those with stationary plaque psoriasis had activities of both neutral proteinases (cathepsin G and elastase) which were about 40% lower than normal controls (P less than 0.05). In the lesion-free psoriatics, the activities of neutral proteinases were about 70% of control values. Our findings emphasize the importance of assessment of disease activity in this sort of investigation. The present data may help to resolve much of the confusion regarding PMN function in psoriasis.