Comparison of the effects of gasoline burn and chromic acid burn on different internal organs and immune functions in rats

Burn as physical injury ranks as the fourth most prevalent trauma across the world. In this study, we aimed to compare the impact of gasoline burn and chromic acid burn on the internal organs and immune functions in rats. The results showed that the levels of methemoglobin (MHb) to total hemoglobin (Hb) as well as the Cr6+ content showed significant elevation in the chromic acid burn group relative to the gasoline burn group. HE staining was used to evaluate the histological changes in the injured tissues as well as the tissues excised from internal organs. We found that chromic acid burn-induced more severe damage to rat tissues. Gasoline burn showed no significant impact on the intestinal tissues of rats, while the chromic acid burn-induced increased cell death in rat intestines. Moreover, the results of HE staining also revealed that gasoline burn and chromic acid burn showed no evident impact on rat hearts. Gasoline burn also showed no significant effects on the liver, lungs and kidneys of rats, while the chromic acid burn caused injuries to such internal organs in comparison with the control and gasoline burn groups. In addition, the MPO activity was higher in the liver, intestine, lungs and kidneys of rats with chromic acid burn. Furthermore, the expression of inflammation response cytokines was examined in the serum of rats. The results demonstrated that the levels of IL-6, IL-1β and TNF-α showed a significant increase in both the gasoline burn and chromic acid burn groups of rats relative to the control, and the levels were higher in the chromic acid burn group in comparison with the gasoline burn group. In conclusion, the chromic acid burn-induced more severe organ injury, inflammation and immune response compared with the gasoline burn, which may provide reference data for the clinical treatment of patients with different burn injuries.

INDICATORS OF HUMORAL IMMUNITY UNDER CHEMICAL BURNS OF ESOPHAGUS IN RATS

It is well known that the immune system has been actively involved in the regeneration and healing processes of post burn wounds. However, unanswered questions remain concerning the role of humoral immunity in the healing mechanisms and development of burn wound complications. We have developed an experimental model of chemical esophageal burn (CEB) which corresponds to esophageal burn in 1-8 years old children. We studied the features of humoral immunity upon CEB in rats. A decrease in IgG levels and an increase in levels of medium- and low- molecular circulating immune complexes (CIC) on the first day of esophageal burns were observed. On the 21st day of burn, we observed an increase in the IgG concentration and a tendency to accumulation of medium- and low-molecular CIC. The studied indicators can be used to differentiate CEB development and create a timeline of burn wounds.

Effect of liposomes containing antioxidant, phospholipid, and amino acid on skin regeneration after chemical burn

Liposomes containing natural flavonoid dihydroquercetin, phospholipid lecithin, and zwitterionic amino acid glycine were used for the therapy of glacial acetic acid-induced chemical burn. No inflammatory reaction was observed in the region of wound. The area of postburn injury did not increase in time. Planimetry and histological studies showed that improved skin regeneration was accompanied by repair of hair follicles and sebaceous glands.

Accelerated wound healing of alkali-burned corneas in MRL mice is associated with a reduced inflammatory signature

PURPOSE

The present study was conducted to investigate healing of alkali-burned corneas in MRL/MpJ (MRL) mice.

METHODS

Gross, clinical, and histologic criteria were used to compare healing of alkali-burned corneas in MRL and control C57BL/6J (B6) mice. Effects of neutrophil depletion of B6 mice and allogeneic reconstitution of B6 mice with MRL bone marrow on wound healing were evaluated. Gene expression patterns in normal and wounded corneas were surveyed with array-based quantitative real-time RT-PCR (AQPCR).

RESULTS

MRL mice showed accelerated reepithelialization and decreased corneal opacity compared with B6 mice after alkali wounding. Marked inflammatory cell infiltration and fibrosis were evident in the corneas and anterior chambers of B6 mice. MRL mice showed less severe lesions, except for stromal edema. Rapid reepithelialization and reduced keratitis/iritis were also observed in neutrophil-depleted B6 mice, but not in B6 mice reconstituted with MRL bone marrow. AQPCR showed transcriptional changes of fewer genes associated with inflammation and corneal tissue homeostasis in alkali-burned corneas from MRL mice. Increased expression of an anti-inflammatory gene, Socs1, and a gene associated with healing, Mmp1a, were evident in MRL corneas.

CONCLUSIONS

Alkali-burned corneas heal faster and more completely in MRL mice than in B6 mice, by means of rapid reepithelialization, reduced inflammation, and reduced fibrosis. Reduced inflammation, including decreased neutrophil infiltrates and the lack of a robust proinflammatory gene expression signature correlates with the rapid healing. However, the rapid-healing phenotype is not intrinsic to MRL hematopoietic progenitor cells.

Differential effects of sustained inflation recruitment maneuvers on alveolar epithelial and lung endothelial injury

OBJECTIVE

The role of recruitment maneuvers in mechanical ventilation for patients with the acute respiratory distress syndrome and acute lung injury remains uncertain in part due to a lack of data on the effects of specific recruitment maneuvers on lung injury severity. The primary objective of this study was to determine the effect of one type of recruitment maneuver--sustained inflation--on alveolar epithelial and lung endothelial injury in experimental acute lung injury.

DESIGN

Randomized experimental study.

SETTING

Academic research laboratory.

SUBJECTS

Forty-nine Sprague-Dawley rats.

INTERVENTIONS

Lung injury was induced in anesthetized, ventilated rats by instillation of acid (pH 1.5) into the airspaces. Rats were ventilated with a tidal volume of 6 mL/kg and a positive end-expiratory pressure of 5 cm H(2)O with or without a sustained inflation recruitment maneuver repeated every 30 mins. Each recruitment maneuver consisted of two 30-sec inflations to total lung capacity (30 cm H(2)O) 1 min apart.

MEASUREMENTS AND MAIN RESULTS

The use of recruitment maneuvers significantly improved oxygenation, compliance, end-expiratory lung volume, functional residual capacity, and deadspace fraction. Recruitment maneuvers reduced extravascular lung water and lung endothelial injury as measured by protein permeability (217 +/- 28 vs. 314 +/- 70 extravascular plasma equivalents [microL], p < .05). However, recruitment maneuvers did not prevent alveolar epithelial injury. Epithelial permeability and bronchoalveolar lavage RTI40 levels, a marker of type I cell injury, were similar with or without recruitment maneuvers. Recruitment maneuvers decreased epithelial fluid transport, a functional marker of epithelial injury. Recruitment maneuvers did not reduce markers of airspace inflammation.

CONCLUSIONS

Sustained inflation recruitment maneuvers improve respiratory mechanics and oxygenation and may protect the lung endothelium but do not reduce alveolar epithelial injury. Because of the differential effects of recruitment maneuvers on the lung endothelium and alveolar epithelium, the net effect in clinical acute lung injury may not be beneficial. Additional clinical studies will be needed to assess the net impact of recruitment maneuvers in patients with acute lung injury.

[The parameters of the body immune reactivity in applying the therapeutic keratoplasty for the treatment of ocular burn lesions of extra severity]

One hundred and two (128 eyes) patients with stage 4 ocular burns underwent examinations. One-stage therapeutic keratoplasty was used in 67 (67.7%) patients. Retransplantation was made in 35 (34.3%) of patients due to graft rejection. According to the study, the more severe the clinical course of burn lesions is (cases that necessitated transplantation in the present research), the more pronounced changes are observed in the body immune reactivity of victims. In particular, the below peculiarities were observed: a progressing reduction of the contents of lymphocytes' and of B-lymphocytes; and a diminishing phagocytic activity of neutrophils in the peripheral blood registered at the terminal treatment stage in the patients after retransplantation versus the 1st-group patients with a more favorable clinical course. The compensatory increase of T-lymphocytes, T-helpers and of IgA, IgG was found to be less pronounced in group 2. A notably more intense sensitization response of the body to corneal antigens was established in the patients after retransplantation, which was a basis for using this index as a prognostication test in respect to the graft rejection crisis.

[Effects of immunization on proteinase-inhibitor balance in the lacrimal fluid and blood serum in alkaline burns of the cornea (an experimental study)]

Proteinase-inhibitor balance in the lacrimal fluid in eye burns was studied in rabbits with modified and intact immune status. Stimulation of the immune system was induced by complete Freund's adjuvant. Clinical picture of the disease was studied in parallel. Immunization accelerated the local adaptive and defense reaction of the proteolytic enzymes and their inhibitors, which was paralleled by a more benign course of burn disease of the eyes, in comparison with that in non-immunized animals.

Thymosin beta 4 promotes corneal wound healing and decreases inflammation in vivo following alkali injury

Previously, thymosin beta 4 (Tbeta(4)) was found to promote wound healing in full thickness skin wounds and heptanol debrided corneas. Here, the effect of Tbeta(4) was examined treatment on corneal wound healing and inflammation in vivo after alkali injury, a more severe wound of the eye. Corneas from 129 Sv mice were chemically burned with a 2 mm disc soaked in 1 N NaOH for 30 sec. Eyes were irrigated copiously with phosphate buffered saline (PBS) and then treated topically with either Tbeta(4) (5 microg/5 microl PBS) or 5 microl PBS twice daily. Animals were killed, the eyes were enucleated, fixed and embedded in plastic resin or prepared for mRNA analysis. Mouse corneas topically treated with 5 microg of Tbeta(4) twice daily after alkali injury demonstrated accelerated re-epithelialization at all time points and decreased polymorphonuclear leukocyte (PMN) infiltration at 7 days post injury (p.i.) when compared to PBS-treated controls. mRNA transcript levels were decreased several fold for interleukin (IL)-lbeta, and the chemokines macrophage inflammatory protein (MIP)-1alpha, MIP-1beta, MIP-2 and monocyte chemoattractant protein (MCP)-1 from 1 to 7 days after injury in the Tbeta(4)- vs. PBS-treated corneas. Thus, Tbeta(4) may provide a new clinical treatment for severe traumatic corneal wound disorders by promoting rapid corneal wound healing and decreasing both PMN infiltration and inflammatory cytokine and chemokine mRNA levels.

Contact dermatitis

Ted is a 38 year old service technician for a large chemical company servicing cooling towers at a car manufacturing plant. While blending a batch of chemicals, he accidentally splashed cooling tower fluid, Kathon, an isothiazolin-3 derivative, over his left forearm. He was wearing long sleeved overalls and safety glasses at the time. About 15 minutes later, Ted experienced some itchiness of his forearm and proceeded to wash the area. He did not change his uniform. Five hours later he experienced severe pain of the forearm. Inspection revealed a 5 cm dermal burn with obvious blistering over the left forearm. He sought medical treatment and was treated conservatively with routine burn dressings. The skin blistering healed after seven days. Ted returned to work undertaking full duties. When undertaking mixing of cooling tower chemicals he developed an itchy rash of the forearms that appeared to be spreading to his hand and shoulder areas. This skin irritation occurred even when there was no contact with cooling tower fluids.

Inhibitory effect of a complementary peptide on ulceration in the alkali-injured rabbit cornea

PURPOSE

Two tripeptide chemoattractants, acetyl-proline-glycine-proline (Ac-PGP) and methyl-proline-glycine-proline (Me-PGP), are the primary triggers for early neutrophil invasion into the alkali-injured cornea. In the present study the effectiveness of a complementary peptide designed to inhibit the PGP chemoattractants (arginine-threonine-arginine [RTR] tetrameric peptide) and an apo A-1 mimicking peptide (5F) was investigated in the alkali-injured rabbit eye.

METHODS

(L)-RTR tetramer, (D)-RTR tetramer, and 5F were tested in vitro for their effects on neutrophil polarization. Synthetic 5F was also tested in vitro for its effect on the neutrophil respiratory burst. In the alkali-injured rabbit eye model, the right corneas of 48 rabbits were exposed to 1 N NaOH for 35 seconds. Sixteen animals were randomly assigned to each of three groups: phosphate-buffered saline (PBS) control; 800 microM RTR (dextrorotatory) tetramer in PBS alternating each hour with 1.5 mM RTR (levorotatory) tetramer in PBS; and 12 microM 5F in PBS. One topical drop of each substance was administered hourly (14 times per day) for 33 days. The experiment was continued until day 42 with no additional drops administered.

RESULTS

(L)-RTR tetramer and (D)-RTR tetramer inhibited neutrophil polarization activated by the PGP chemoattractants in vitro. Synthetic 5F did not inhibit neutrophil polarization in the presence of Ac-PGP or the respiratory burst of neutrophils in the presence of a metabolic stimulant derived from alkali-degraded corneas. During the entire animal experiment, statistically fewer ulcers occurred in the RTR tetramer group than in the PBS control group (43.8% vs. 87.5%, P = 0.0046). The frequency of ulceration in the 5F group (68.8%) was not significantly different from the PBS control group.

CONCLUSIONS

The reduction in the frequency of corneal ulceration by the RTR tetramer possibly resulted from its complementary binding to Ac-PGP and Me-PGP in the cornea shortly after alkali injury, leading to a reduction in the early and late infiltration of neutrophils. RTR tetramer appears to hold enough promise to warrant additional study as a therapeutic drug for the alkali-injured eye.

[Immunologic experimental studies on the alkali burn of cornea in rats]

OBJECTIVE

To investigate the immune reaction of severe corneal alkali burns.

METHODS

The models of severe corneal alkali burns were induced in rats. Immunohistochemistry was carried out on wholemounts of the cornea and iris at different time points after corneal burns to detect T-lymphocytes and their subpopulation, macrophages, dendritic cells and MHC class II -positive cells.

RESULTS

In the early stage of the burns, there were small increasing number of T-lymphocytes and MHC class II-positive cells in the cornea and iris. At the period of corneal melting and perforation, a massive influx of lymphocytes (CD(+)(3), CD(+)(4), CD(+)(8)), macrophages and dendritic cells was seen in the cornea adjacent to the limbus and iris. CD(+)(4) lymphocytes were much more than CD(+)(8) in number. T-cells and MHC class II-positive cells were observed not only at the limbus but also in the melting area and corneal center. Morphological changes of these cells were also noted. In the restoration stage, a number of positive cells were still found in the iris.

CONCLUSION

Immunological mechanism is involved in the pathological changes of the damage induced by corneal alkali burns, especially in the pathogenesis of the corneal melting and perforation.

Injection of chemoattractants into normal cornea: a model of inflammation after alkali injury

PURPOSE

The objective of this study was to establish and characterize the invasion of polymorphonuclear leukocytes (PMNs) into a normal cornea after intrastromal injection of the tripeptide chemoattractants generated from alkali-degraded corneas.

METHODS

The following samples were injected into the midstroma of normal rabbit corneas: ultrafiltered tripeptide chemoattractants (N-acetyl-proline-glycine-proline and N-methyl-proline-glycine-proline) generated from alkali-degraded corneas, synthetic N-acetyl-PGP, positive control (leukotriene B4 [LTB4]), or negative control (Hanks' balanced salt solution [HBSS]). Timed responses of PMN infiltration were established for effective concentrations of LTB4 or the ultrafiltered chemoattractants.

RESULTS

All intrastromal injections resulted in the immediate development of an edematous disc that was 10 mm in diameter. The lesion essentially had cleared in the HBSS-injected eyes by 8 hours, and histologic sections revealed minimal numbers of PMNs in the cornea or limbal tissue. The injection of LTB4 or the ultrafiltered tripeptide chemoattractants induced peak numbers of PMNs within the stroma at 8 hours, subsiding by 16 hours. Seventy units of ultrafiltered chemoattractants yielded a strong PMN response, similar to 1 X 10(-5) M LTB4. The highest concentration of ultrafiltered chemoattractants (350 U) produced a severe PMN response that was characterized by a solid sheet of neutrophils surrounding the injection site. The injection of synthetic N-acetyl-PGP (2 X 10(-4) M) produced a marked PMN response.

CONCLUSIONS

PMN invasion of the normal cornea after the injection of the ultrafiltered tripeptide chemoattractants or the synthetic N-acetyl-PGP mimicked early PMN infiltration in the alkali-injured eye, confirming the importance of this chemoattractant as an inflammatory mediator.

[Natural cytokine complex as a drug bioregulator in healing of alkaline burns of cornea (experimental morphological study)]

Clinical morphological features of reparative processes of alkaline burns of the cornea are studied in 24 rabbits. Effects of the natural cytokine complex on this process are validated. Burn process is regarded as an immune inflammation. Morphological and morphometric data demonstrate the mechanism of the cytokine effect on the reparative processes in the cornea, based on the regulation of the inflammatory postburn and proliferative processes. The repair of the cornea after burn in experiment and control is described in detail.

[An experimental study on immune mechanism after alkali burn in the anterior segment of rabbit eye]

OBJECTIVE

To study the immunologic mechanism of corneal ulceration after alkali burn.

METHODS

55 rabbits with alkali burn in right eye were randomly divided into two groups. In group I (31 animals), the level of circulating immune complex (CIC), the rate of red blood cell C3b receptor complex rosette (RBC-C3bRR) and immune complex rosette (RBC-ICR) were measured respectively at 7, 14, 21, 35, 49 days after alkali burn. In Group 2 (24 animals), the immune complex was detected by means of immunofluorescence (IF) and immunogold-silver staining (IGSS) in burned tissues at 21 days after burn. Histopathologic changes were also observed under light microscope.

RESULTS

CIC, the rate of RBC-C3bRR and RBC-ICR were markedly increased 14 to 21 days after burn. In the mean time, the deposition of immune complex was found in burned tissues and the accumulation of polymorphonuclear leukocyte (PMN) was observed at the base of corneal ulcer.

CONCLUSIONS

The immune mechanism indeed participates in the pathogenesis of corneal ulceration and also aggravates the progress of ulceration on the base of chemical injury.

Appearance of immune cells and expression of MHC II DQ molecule by fibroblasts in alkali-burned corneas

Corneal alkali burns are characterized by persistent inflammatory response and recurrent epithelial erosions. We examine whether immune cell types, i.e., T-cells and B-cells, play a role in this devastating process. Rabbit alkali-burned corneas that healed for 1-49 days were subjected to immunostaining with monoclonal antibodies (mAb) L11/135 (anti-T-cells), and 2C4 (anti-MHC II DQ). Serum was collected weekly and subjected to Western blot immunostaining to detect antibodies against denatured corneal proteins. Our observations demonstrated that all injured corneas reepithelialized within 3 days but then developed recurrent erosions. Immunohistochemical studies revealed that PMN, monocytes, and B-cells labeled by 2C4 mAb and T-cells labeled by L11/135 mAb appeared in the periphery to the cornea at 1 day after alkali burn. Many of these myeloid and lymphoid cells invaded the central stroma after 2 weeks of injuries when the alkali-burned corneas were heavily vascularized. In addition, some fibroblastic cells also expressed the MHC II DQ molecules in the alkali-burned corneas that had healed for > 2 weeks. Plasma cells appeared in granulation tissue of injured corneas that had healed for > 3 weeks. Western blot analysis demonstrated a production of heterogeneous antibodies in a majority of the rabbits (11 of 14) to various denatured corneal proteins (between 80 kDa and 25 kDa) at 5 weeks of alkali burn. Inflammatory cell types, i.e., PMN, macrophages could be found underneath the detached epithelium. These observations are consistent with the notion that the myeloid and lymphoid cells may participate in and complicate the healing of corneal alkali burns.

Alpha/beta- and gamma/delta-T-cell-receptor-positive lymphocytes in healthy and inflamed human conjunctiva

BACKGROUND

The possible existence and distribution patterns of alpha/beta- and gamma/delta-TCR+ cells, which are important constituents of immune surveillance and act via the CD3+ cell complex have not yet been elucidated in the healthy and inflamed conjunctiva.

MATERIALS AND METHODS

Paraffin-embedded conjunctival specimens included 18 from 18 patients with ocular cicatricial pemphigoid (OCP), 20 from 20 healthy controls, 6 from 6 patients with lye burns, and 6 from 2 patients with Stevens-Johnson syndrome; all were worked up by histology and immunohistochemistry.

RESULTS

alpha/beta-TCR+ cells were visualized in the conjunctival epithelium and stroma of healthy persons, OCP, lye burns and Stevens-Johnson syndrome. alpha/ beta-TCR+ cells and a small number of gamma/delta-TCR+ cells were observed in the corneal epithelium and stroma of patients who have failing corneal grafts. After ileal mucosa transplantation to the epibulbar conjunctiva, membrane staining changes to nuclear and cytoplasmic staining. Treatment with systemic cytotoxic drugs abolishes all alpha/beta-TCR+ and gamma/delta-TCR+ cells.

CONCLUSIONS

alpha/beta-TCR+ cells can be found in the non-infected epithelium and stroma of the healthy and inflamed (OCP, lye burns, and Stevens-Johnson syndrome) conjunctiva, as well as in the corneal epithelium and stroma of failing corneal grafts, whereas gamma/delta-TCR+ cells are absent. A small number of gamma/delta-TCR+ cells are present in the corneal stroma and adjacent conjunctival epithelium of patients with chronic corneal graft rejection or after transplantation of gut tissue. Further investigations may establish the role, if any, of these T-cell subsets in immune surveillance of the non-infected outer eye and in corneal graft rejection.

A single accidental exposure may result in a chemical burn, primary sensitization and allergic contact dermatitis

It is known from experimental studies that antigenic potency and the concentration of antigen determine whether exposure to an antigen will result in sensitization. A single accidental exposure to concentrated antigen may therefore induce primary sensitization. The purpose of this report was to collect clinical cases in which a single exposure had resulted in contact dermatitis suspected to be allergic. Only patients without previous relevant skin symptoms were included. Patch testing was used to demonstrate sensitization. 6 patients developed occupational allergic contact dermatitis from accidental exposure. Patch testing revealed allergy to diglycidylether of bisphenol A epoxy resin, polyfunctional aziridine hardener, methyl acrylate, phenol-formaldehyde resin, and methylchloroisothiazolinone/methylisothiazolinone (Kathon LX), respectively. Furthermore, 2 patients developed allergic contact dermatitis from their first exposure to tear gas chemicals, namely omega-chloroacetophenone and ortho-chlorobenzylidene malonitrile. A single exposure can therefore induce both sensitization and subsequent allergic contact dermatitis without further exposure. The allergens described must be considered strong allergens. The skin should immediately be cleaned if an accidental splash with such an allergen has taken place.

Suppression of corneal allograft rejection by systemic cyclosporine-A in heavily vascularized rabbit corneas following alkali burns

Immunologic rejection is the main cause of corneal graft failure, especially in vascularized corneal beds. The purpose of this study was to investigate the effect of systemic Cyclosporine-A (CsA) on the survival of corneal allografts in heavily vascularized rabbit corneal beds, following alkali burn. Heavy corneal vascularization was induced in one eye of 20 rabbits by alkali burn. Forty-five days later, penetrating keratoplasty was performed in all the heavily vascularized corneas. Twenty-five mg/kg/day of CsA was intramuscularly administered to 10 rabbits for 30 days. The other 10 rabbits were treated with the solvent without CsA and were used as a matched control group. The results show a significant difference in corneal allograft survival between the two groups. All corneal grafts in the untreated group were intensely rejected and vascularized within 3 weeks. Nine of the 10 corneal transplants, in the CsA-treated group, remained transparent without signs of immunologic rejection for > 180 days. In one corneal transplant, minor signs of rejection occurred. We suggest that CsA, when given systemically, is a potent drug in the prevention of immunologic rejection in high-risk corneal transplantations, such as allografts, in heavily vascularized corneas following alkali burn.

Subconjunctival injection of purified blood mononuclear cells into alkali-injured rabbit eyes

Monocytes transform into tissue macrophages that scavenge necrotic debris from wounds but also release substances stimulatory to fibroblasts. In an effort to encourage the healing process, monocytes, purified from rabbit blood, were injected subconjunctivally 1 or 2 days and 6 or 7 days after alkali injury to the rabbit eye. The injected monocytes failed to alter the course of the alkali-injured eyes. Specifically, the incidence of corneal ulceration in the experimental group was not statistically different from that of the control group. A byproduct of this study was a presentation of the technique to purify platelet-free mononuclear leukocytes from rabbit peripheral blood.

T6-positive Langerhans cells in diseased corneas

Langerhans cells (LC) in normal human corneas (with the exception of newborns) lack thymocyte antigen T6, a highly specific marker for noncorneal LC. Because corneal LC could not be induced to express T6 antigen when cultured with various cytokines including interleukin-1 (shown to modulate T6 expression on gingival LC), some authors assume that corneal LC may represent a distinct LC subpopulation that is innately inactive. In this study, 62 corneas from patients with various corneal diseases were investigated for the presence of T6 and histocompatibility antigen HLA-DR on LC in the central and pericentral epithelium. Both T6- and HLA-DR-positive LC at a high density similar to that observed in normal epidermis could be detected in the epithelium of five corneas with epidermalization after alkali burns. Furthermore T6- and HLA-DR-positive LC at smaller densities also were detected in corneas from patients with chronic herpetic stromal keratitis, zoster keratitis, chronic allograft rejection, and bacterial corneal ulcers. Although the functional significance of T6 expression on corneal LC remains to be determined, the induction of T6 antigen on corneal LC may represent an important event for the antigen-presenting function of these cells in various corneal diseases including corneal allograft rejection.

[Immune reactions of the conjunctiva and cornea following severe chemical burns of the outer eye]

Conjunctival and corneal tissue samples from nine patients with severe changes after acid and alkali burns were examined immunohistochemically. Epithelial HLA Class II antigen expression was present in three of five conjunctival samples, and all of the antigen markers examined in the conjunctival stroma could be stained. HLA Class II expression was demonstrated in four out of five corneal tissue samples. The results show that in Grade III or IV chemical burns, with the diverse changes of the external eye that they produce, immunological and possibly also autoimmune mechanisms can influence the clinical course.

Clinical and experimental studies concerning circulating antibodies to corneal epithelium antigens

Corneal epithelium antibodies were detected in patients with corneal melting disease (55%), uveitis (42%), corneal transplantation (42%) and marginal furrow disease (20%). These antibodies were not found in herpetic keratitis patients. In control groups, consisting of ocular surgery patients (glaucoma, retinal detachment and cataract) and persons without a history of ocular disease, approximately 4% of the subjects had these antibodies. To investigate the possible role of trauma to the cornea as an initiator of corneal epithelium antibodies, these antibodies were determined in rabbits after alkaline burns were made on the cornea. These antibodies were detected one week later and disappeared after six weeks. Serum from three patients with corneal melting disease and corneal transplantation containing a high antibody titre against corneal epithelium were used to isolate corneal epithelium antigens. A 54 kD and a 17 kD corneal epithelium antigen were isolated. The incidence of autoantibodies directed against these antigens was investigated in patients with corneal melting disease, uveitis and corneal transplantation using an ELISA. 50% of the sera positive in the immunofluorescence test were positive in the ELISA.

Further evidence for the involvement of immunoregulatory processes in corneal alkali burns: effects of immunosuppression and convalescent serum

Alkali burns were produced in one eye of a group of mice. Two, 3 and 4 weeks later the second eye of each mouse was similarly burned. The rate of perforation in the second-burned eyes was significantly higher than in the first eye. This effect was abolished by immunosuppressing the animals before the burning of the first eyes. This potentiation effect of an ocular burn on subsequent ones is transferable to other mice by intraperitoneal administration of convalescent serum prepared from mice that were previously burned. This evidence suggests that ocular alkali burns cause the appearance in the circulation of antigens not previously present there. The antibodies produced against these antigens exacerbate the subsequent burn lesion and perhaps also the condition of the original burn.

The effect of sodium citrate on the stimulation of polymorphonuclear leukocytes

Topical administration of sodium citrate reduces the incidence of corneal ulceration and perforation following an alkali burn to the eye. The specific mechanism by which sodium citrate prevents the ulceration is not understood, although citrate does inhibit the infiltration of polymorphonuclear leukocytes (PMNs) into the cornea following an alkali burn. In the present study, the effects of sodium citrate and another calcium chelator, ethylene glycol bis (beta-aminoethylether)-N,N'tetraacetic acid (EGTA), upon PMN oxygen consumption and lysosomal enzyme release were determined. Oxygen consumption was measured polarographically using a Clark-type oxygen electrode, and lysosomal enzyme release was determined by intra- and extra-cellular measurements of myeloperoxidase activity. Opsonized zymosan and N-formylmethionylleucylphenylalanine (FMLP) were used to stimulate neutrophil oxygen consumption and lysosomal release. Both sodium citrate and EGTA inhibited PMN oxygen consumption and lysosomal enzyme release in response to opsonized zymosan. In contrast, neither sodium citrate nor EGTA reduced PMN oxygen consumption or lysosomal enzyme release in response to FMLP. Therefore, the ability of sodium citrate (and EGTA) to inhibit PMN stimulation is dependent upon the choice of stimulus. Until the inflammatory mediators involved in the ulcerative process following an alkali burn to the eye are delineated, the impact of sodium citrate upon PMN stimulation in vivo cannot be resolved.

Indications for the role of the immune system in the pathogenesis of corneal alkali burns

We produced alkali burns (1.5 N NaOH) in the right eyes of 63 mice. Three weeks later the left eye of each mouse was similarly burned. All eyes were followed up weekly for 4 weeks after the burn and were graded according to the severity of the lesion. The lesions developed much faster and were more severe in the left eyes. These results suggest that the body's immune mechanism participates in the pathogenesis of alkali corneal burns and adversely affects the development of this condition.

Postburn immunosuppression in an animal model: monocyte dysfunction induced by burned tissue

We studied cell-mediated immunity (CMI) in burned mice using an assay that involves the induction of contact sensitivity to dinitrofluorobenzene (DNFB). Subsequent painting of the ears with DNFB and measurement of ear swelling with calipers is a sensitive and quantifiable assay for CMI. Results may be expressed as mean ear swelling (MS) in units of 10(-4) inches +/- 2 standard errors of the mean. CMI was severely depressed in burned mice over a 2-week period following burn (control MS 48.3 +/- 1.0, 14 days after burn 29.0 +/- 1.0, P less than 0.01). Immediate postburn eschar removal resulted in avoidance of immunosuppression (MS 41.5 +/- 1.0, P less than 0.01) while transfer of burned tissue subcutaneously into unburned mice resulted in severe immunosuppression (MS 33.2 +/- 2.6, P less than 0.01). CMI was restored by intravenous infusion of peritoneal macrophages from unburned mice (MS 41.4 +/- 2.2), but not by infusion of lymphocytes or of macrophages taken from burned mice. This model should prove useful for further study of burn injury-induced immunosuppression.

Changes in humoral components of host defense following burn trauma

Serum opsonic activity for E. coli 075, conversion of C3 by inulin, total hemolytic complement (CH(50)), levels of native C3, factor B, C3b inactivator (KAF), properdin (P), and immunoglobulins (Ig) were determined in 14 patients with burns involving 13% to 91% body surface during 6 to 8 weeks postburn. In the 12 uninfected patients, levels of IgG and IgA were reduced during the first 10 days postburn, and decreased concentrations of P and IgM were demonstrated from three to 6 weeks postburn. C3 conversion was reduced from 10 days to 6 weeks postburn. Levels of C3, factor B, and KAF were normal or elevated for the entire study period. No difference in the occurrence of humoral abnormalities was noted in patients with burns caused by flame, immersion scald, or acid contact. Reduction in C3 conversion and P concentration were the only abnormalities which correlated with increasing burn size. Bacteremia and/or fungemia was documented in the other two patients. In one of these patients, reduction in CH(50) occurred during septicemia due to S. aureus, and in the other, reduction in all measurements of complement was associated with candidemia and Pseudomonas septicemia and occurred prior to the development of shock. Serum opsonic activity was only reduced significantly during sepsis, suggesting that this abnormality occurred as a result rather than a cause of infection. These results indicate that consumption of components of the classical and/or alternative pathways of complement activation may be an important mechanism by which infection is perpetuated in the burn patient. They also emphasize the importance of the clinical management of the burn patient in preventing the development of septic complications.

Complement in pemphigus vulgaris and other bullous dermatoses

The behavior of the complement and of its components C4 and C3 has been studied in serum and in blister fluid both in patients with pemphigus vulgaris and other bullous dermatoses and in healthy subjects with experimentally induced blisters. The results are suggestive of local activation of the complement, in the blister fluid of patients with pemphigus vulgaris, pemphigus erythematosus and bullous pemphigoid according to the classical enzymatic sequence.