Relevance of lymphocyte proliferation to PHA in severe combined immunodeficiency (SCID) and T cell lymphopenia

Severe combined immunodeficiency (SCID) is characterized by a severe deficiency in T cell numbers. We analyzed data collected (n = 307) for PHA-based T cell proliferation from the PIDTC SCID protocol 6901, using either a radioactive or flow cytometry method. In comparing the two groups, a smaller number of the patients tested by flow cytometry had <10% of the lower limit of normal proliferation as compared to the radioactive method (p = 0.02). Further, in patients with CD3+ T cell counts between 51 and 300 cells/μL, there was a higher proliferative response with the PHA flow assay compared to the 3H-T assay (p < 0.0001), suggesting that the method of analysis influences the resolution and interpretation of PHA results. Importantly, we observed many SCID patients with profound T cell lymphopenia having normal T cell proliferation when assessed by flow cytometry. We recommend this test be considered only as supportive in the diagnosis of typical SCID.

Post-SARS-CoV-2 Atypical Inflammatory Syndrome in a Toddler with X-Linked Inhibitor of Apoptosis Deficiency After Stem Cell Transplant

A 10-month-old boy was diagnosed with X-linked lymphoproliferative syndrome type 2 due to X-linked inhibitor of apoptosis deficiency after presenting with failure to thrive and refractory inflammatory bowel disease. He underwent a matched unrelated donor stem cell transplant with reduced intensity conditioning at 16 months. At 27 months, he presented with an atypical inflammatory syndrome in the setting of recent COVID-19 infection, Epstein-Barr viremia, and low chimerism (7.3%). He recovered after treatment with intravenous immunoglobulin and steroids.

An essential role for the Zn2+ transporter ZIP7 in B cell development

Despite the known importance of zinc for human immunity, molecular insights into its roles have remained limited. Here we report a novel autosomal recessive disease characterized by absent B cells, agammaglobulinemia and early onset infections in five unrelated families. The immunodeficiency results from hypomorphic mutations of SLC39A7, which encodes the endoplasmic reticulum-to-cytoplasm zinc transporter ZIP7. Using CRISPR-Cas9 mutagenesis we have precisely modeled ZIP7 deficiency in mice. Homozygosity for a null allele caused embryonic death, but hypomorphic alleles reproduced the block in B cell development seen in patients. B cells from mutant mice exhibited a diminished concentration of cytoplasmic free zinc, increased phosphatase activity and decreased phosphorylation of signaling molecules downstream of the pre-B cell and B cell receptors. Our findings highlight a specific role for cytosolic Zn2+ in modulating B cell receptor signal strength and positive selection.

Flebogamma(®) 5 % DIF Intravenous Immunoglobulin for Replacement Therapy in Children with Primary Immunodeficiency Diseases

PURPOSE

The previous studies with Flebogamma(®) 5 % DIF intravenous immunoglobulin (IVIG) contained insufficient numbers of pediatric subjects to fully warrant a pediatric indication by the FDA. The objective of this study was to evaluate the efficacy, safety, and pharmacokinetics of Flebogamma® 5 % DIF for replacement therapy in children (age 2-16) with primary immunodeficiency diseases (PIDD).

METHODS

IVIG was administered at eight clinical sites to 24 subjects with well-defined PIDD at a dose of 300-800 mg/kg every 21-28 days for 12 months. The pharmacokinetics endpoint in this study was the dose-adjusted increment of the serum IgG trough levels.

RESULTS

The calculated serious bacterial infection rate was 0.05/subject/year. The incidence of adverse events considered potentially related to IVIG during or within 72 h after completing an infusion was within the FDA guidance threshold of <40 % at each time point. Dose-adjusted incremental IgG levels remained approximately equal to or slightly greater than pre-study IgG levels (between 800 and 1000 mg/dL throughout) when the subjects were treated with IVIG therapy other than Flebogamma(®) DIF 5 % indicating no evidence of a different pharmacokinetic profile in this pediatric population if compared to those profiles in previous Flebogamma studies in predominately adult populations.

CONCLUSIONS

Flebogamma(®) 5 % DIF is efficacious and safe, has adequate pharmacokinetic properties, is well-tolerated, and maintains the profile of Flebogamma(®) 5 % for the treatment of children with primary humoral immunodeficiency diseases.

Mesenchymal stem cells enhance allogeneic islet engraftment in nonhuman primates

OBJECTIVE

To test the graft-promoting effects of mesenchymal stem cells (MSCs) in a cynomolgus monkey model of islet/bone marrow transplantation.

RESEARCH DESIGN AND METHODS

Cynomolgus MSCs were obtained from iliac crest aspirate and characterized through passage 11 for phenotype, gene expression, differentiation potential, and karyotype. Allogeneic donor MSCs were cotransplanted intraportally with islets on postoperative day (POD) 0 and intravenously with donor marrow on PODs 5 and 11. Recipients were followed for stabilization of blood glucose levels, reduction of exogenous insulin requirement (EIR), C-peptide levels, changes in peripheral blood T regulatory cells, and chimerism. Destabilization of glycemia and increases in EIR were used as signs of rejection; additional intravenous MSCs were administered to test the effect on reversal of rejection.

RESULTS

MSC phenotype and a normal karyotype were observed through passage 11. IL-6, IL-10, vascular endothelial growth factor, TGF-β, hepatocyte growth factor, and galectin-1 gene expression levels varied among donors. MSC treatment significantly enhanced islet engraftment and function at 1 month posttransplant (n = 8), as compared with animals that received islets without MSCs (n = 3). Additional infusions of donor or third-party MSCs resulted in reversal of rejection episodes and prolongation of islet function in two animals. Stable islet allograft function was associated with increased numbers of regulatory T-cells in peripheral blood.

CONCLUSIONS

MSCs may provide an important approach for enhancement of islet engraftment, thereby decreasing the numbers of islets needed to achieve insulin independence. Furthermore, MSCs may serve as a new, safe, and effective antirejection therapy.

Comèl-Netherton syndrome defined as primary immunodeficiency

BACKGROUND

Mutations in serine protease inhibitor Kazal-type 5 (SPINK5), encoding the serine protease inhibitor lympho-epithelial Kazal-type 5 related inhibitor (LEKTI), cause Comèl-Netherton syndrome, an autosomal-recessive disease characterized by congenital ichthyosis, bamboo hair, and atopic diathesis. Despite increased frequency of infections, the immunocompetence of patients with Comèl-Netherton syndrome has not been extensively investigated.

OBJECTIVE

To define Comèl-Netherton syndrome as a primary immunodeficiency disorder and to explore the benefit of intravenous immunoglobulin replacement therapy.

METHODS

We enrolled 9 patients with Comèl-Netherton syndrome, sequenced SPINK5, and analyzed LEKTI expression by immunohistochemistry. Immune function was assessed by measuring cognate immunity, serum cytokine levels, and natural killer cell cytotoxicity.

RESULTS

All patients presented with recurrent skin infections caused predominantly by Staphylococcus aureus. All but 1 reported recurrent respiratory tract infections; 78% had sepsis and/or pneumonia; 67% had recurrent gastrointestinal disease and failure to thrive. Mutations in SPINK5-including 6 novel mutations-were identified in 8 patients. LEKTI expression was decreased or absent in all patients. Immunologic evaluation revealed reduced memory B cells and defective responses to vaccination with Pneumovax and bacteriophage phiX174, characterized by impaired antibody amplification and class-switching. Immune dysregulation was suggested by a skewed T(h)1 phenotype and elevated proinflammatory cytokine levels, whereas serum concentrations of the chemokine (C-C motif) ligand 5 and natural killer cell cytotoxicity were decreased. Treatment with intravenous immunoglobulin resulted in remarkable clinical improvement and temporarily increased natural killer cell cytotoxicity.

CONCLUSION

These data provide new insights into the immunopathology of Comèl-Netherton syndrome and demonstrate that this multisystem disorder, characterized by lack of LEKTI expression in epithelial cells, is complicated by cognate and innate immunodeficiency that responds favorably to intravenous immunoglobulin therapy.

[Critical value of citrulline for complications of intestinal transplant graft]

OBJECTIVE

A biochemical marker for detection of acute cellular rejection following small intestine transplantation has been sought. Citrulline, a non- protein amino acid synthesized mainly by functioning enterocytes, has been proposed. Trial sensitivity has been reportedly high but with low specificity. Thus, the goal was to determine, in a sufficiently large analysis, the significant value of citrulline level in the post-transplant setting, which would correlate with complications such as rejection and infection.

METHODS

Since March, 2004 2,135 dried blood spot (DBS) citrulline samples were obtained from 57 small intestine transplant recipients three months or more after post-transplant, i.e., once the expected period of recovery in the citrulline levels had occurred.

RESULTS

Using a <13 vs. > 13 micromoles/L cut off point, sensitivity of DBS citrulline for the detection of moderate or severe ACR was extremely high (96.4%). Furthermore, specificity estimates (given the absence of ACR and these particular infections), while controlling for time-to-DBS sample were reasonably high (54%-74% in children and 83%-88% in adults), and the negative predictive value (NPV) was >99%.

CONCLUSION

Citrulline is a non-invasive marker to evaluate problems of the intestinal graft after three months post-transplant. Due to the high NPV, a moderate or severe ACR can be ruled out, based exclusively on knowledge of a high value for DBS citrulline.

Transplantation of the spleen: effect of splenic allograft in human multivisceral transplantation

OBJECTIVES

To describe the effect of the splenic allograft in human multivisceral transplantation.

SUMMARY BACKGROUND DATA

We performed transplants of the spleen as part of a multivisceral graft in an attempt to decrease both the risk of infection from an asplenic state and the risk of rejection by a possible tolerogenic effect. To our knowledge, this is the first report of human splenic transplantation in a large series.

METHODS

All primary multivisceral recipients who received a donor spleen (N = 60) were compared with those who did not receive a spleen (N = 81).

RESULTS

Thirty-five of 60 (58%) are alive in the spleen group, and 39 of 81 (48%) are alive in control group (P = 0.98). In univariate analysis, splenic recipients showed superiority in freedom-from-any rejection (P = 0.02) and freedom-from-moderate or severe rejection (P = 0.007). No significant differences were observed in analyses of infectious complications between the spleen and control groups. Both platelet and leukocyte counts became normal in splenic patients, whereas these counts were significantly increased in nonsplenic recipients. Observed incidence of graft versus host disease (GVHD) was 8.25% (5 of 60) in the spleen group and 6.2% (5 of 81) in the control group (P = 0.70). Increased incidence of autoimmune hemolysis was observed in the spleen group.

CONCLUSIONS

Allograft spleen can be transplanted within a multivisceral graft without significantly increasing the risk of GVHD. The allogenic spleen seems to show a protective effect on small bowel rejection. Further investigation with longitudinal follow-up is required to precisely determine the immunologic and hematologic effects of the allograft spleen.

FoxP3 mRNA transcripts and regulatory cells in renal transplant recipients 10 years after donor marrow infusion

BACKGROUND

We update more favorable 10-year deceased donor kidney transplant survival in 63 recipients infused perioperatively with donor vertebral body bone marrow (DBMC-i) vs. 219 noninfused controls having equivalent immunosuppression and demographics. We questioned if this was associated with putatively regulatory FoxP3 mRNA and cell phenotypes (CD4+CD25+high percentages and high DC2:DC1 ratios) in DBMC-i vs. noninfused controls.

METHODS

Baseline studies were performed on peripheral blood lymphocytes (PBLs) vs. marrow in normal laboratory volunteers of CD4+CD25+high percentages and DC2:DC1 by flow cytometry, and FoxP3 mRNA in CD3+ cells by real-time polymerase chain reaction. Similar studies were performed on PBL of the majority of the 10-year patients remaining with graft function: 21 (of the remaining 37) DBMC-i vs. 55 (of the remaining 105) controls.

RESULTS

In normal subjects, all parameters were significantly higher in marrow than in PBL, supporting our previous reports of ex vivo DBMC immunoregulation. At 9.8+/-.02 years posttransplant in DBMC-i vs. controls, death-censored percent graft failure was 17.5% vs. 32.9% (P=0.02) with 247.6+/-24 vs. 79.9+/-3.1 (mean+/-SE) FoxP3 copies/5,000 CD3+ cells (P=0.0001). PBL CD4+CD25+high percentages were lower, but DC2:DC1 values higher in both recipient groups than in end-stage renal disease patients who had lower FoxP3 levels (40.8+/-5.9, P<0.0001), consistent with non-CD4+CD25+high T regulatory cells generated long-term posttransplant. Individual higher FoxP3 values correlated with higher iliac crest chimerism in DBMC-i, but not in controls (with 50-fold lower chimerism). In chronically rejecting controls, FoxP3 was further decreased.

CONCLUSIONS

Peritransplant DBMC-i has higher 10-year renal transplant acceptance, chimerism, and FoxP3 mRNA in thus-far unclarified regulatory cell phenotypes.

Generalized erythrodermic pemphigus foliaceus in a child and its successful response to rituximab treatment

Pemphigus foliaceus is an autoimmune disease that clinically manifests with cutaneous blisters of the superficial skin. The nonendemic or sporadic form of this entity is rare in children and typically presents with a milder, more localized rash that usually follows a benign course of short duration. We describe an affected patient atypical in both her young age and the severity of skin findings. Our patient presented with a full body exfoliative erythroderma at 21 months of age. After an extensive work-up to determine the etiology of her exfoliative erythroderma, direct and indirect immunofluorescence studies confirmed the diagnosis of pemphigus foliaceus. Rituximab therapy was initiated based on the patient's refractory disease course to multiple immunosuppressive agents. Rituximab is a therapeutic monoclonal antibody targeting CD20, an integral membrane protein highly expressed on the surface of pre-B lymphocytes and activated mature B lymphocytes. The patient's skin exhibited marked clinical improvement after the start of rituximab infusions over 12 weeks. Her initial desmoglein 1 antibody level was greater than 1:1280, which decreased to 1:16 after seven rituximab treatments. She has had no skin flares since initiating treatment with rituximab therapy. Based on this clinical and serologic response, the use of rituximab may be helpful in the treatment of pediatric pemphigus foliaceus refractory to mainstays of therapy.

Neuron-like differentiation of adipose-derived stem cells from infant piglets in vitro

BACKGROUND/OBJECTIVE

Adipose-derived stem cells (ADSCs) are mesenchymal stem cells (MSCs) that can be extracted from adipose tissue and obtained by a less invasive method and in larger quantities compared with bone marrow-derived MSCs. The objective of this study was to harvest ADSCs from piglets and to explore their neuronal differentiation potential.

METHODS

Adipose tissue from piglet facial or abdominal fat was digested with collagenase type XI, followed by filter and centrifugation; the isolated adipose stromal cells were cultured in dishes. MSC markers were measured by flow cytometry; 2 to 5 passage cells were used for in vitro differentiation. Adipogenic, chondrogenic, osteogenic, and neuronal differentiation was induced by incubation of the ADSCs with different induction media.

RESULTS

ADSCs were easily expanded to beyond 15 passages, maintaining the undifferentiated state and exhibiting MSC characteristics and markers CD29, CD44, and CD90. ADSCs differentiated into other mesodermal cells including adipocytes, chondrocytes, and osteocytes. These cells were induced to differentiate into neuron-like cells as evidenced by neuronal morphology and the presence of neuronal markers including microtubule-associated protein 2, neuronal nuclear antigen, and beta-tubulin III.

CONCLUSIONS

ADSCs can be readily obtained from a small amount fat tissue and expanded in culture. Adipose tissue may be an alternative source of stem cell therapy for nervous system injury.

An association of lower serum citrulline levels within 30 days of acute rejection in patients following small intestine transplantation

INTRODUCTION

In a prospective protocol we studied whether serum citrulline level within 30 days of an acute rejection was predictive of the episode.

METHODS

An acute rejection episode was defined as the date of occurrence of any biopsy-proven rejection in which treatment was initiated until two successive biopsies showed no further rejection. We compared the mean citrulline level based on values determined within 30 days of the start of an acute rejection episode with the mean citrulline level measured on the same patient during a rejection-free period. Serum citrulline measurements were available immediately prior to the occurrence of rejection for 22 patients who experienced 37 episodes.

RESULTS

For the 12 episodes of mild rejection, the mean serum citrulline level +/- SE (standard error) was 15.0 + 2.3 micromol/L prior to rejection and 18.8 +/- 2.4 micromol/L during the rejection-free periods. A paired t test of the mean differences was not significant (P = 17). For the 25 episodes of moderate or severe rejection, the mean serum citrulline level was 12.4 +/- 1.1 micromol/L before rejection and 18.8 +/- 2.0 micromol/L during the rejection-free periods. A paired t test of the mean difference was statistically significant (P = .002).

CONCLUSIONS

Although further study of citrulline as a marker for the early detection of acute rejection episodes is needed, our hope is that its use will help to prevent some of these early episodes from evolving into full-blown moderate or severe grades of rejection.

Inclusion of spleen in pediatric multivisceral transplantation

Inclusion of the donor spleen may be beneficial for small children who receive multivisceral transplantation (MVT) because asplenia is associated with increased risk of bacterial sepsis. Beginning in 2003, the spleen was transplanted together with multivisceral transplantation in 17 children under daclizumab induction (spleen group). The results were compared to 23 children who received multivisceral transplantation without the spleen (control group) with the same immunosuppression regimen. Median age of 17 patients who received a spleen was 0.80 years (range 0.54-1.66). Platelet counts at 30 and 60 days posttransplant were significantly lower in the spleen group (average values: day 30: 399,000 vs 636,000, P = .015; day 60: 413,000 vs 622,000, P = .0056). WBC counts at 30 and 60 days posttransplant were also decreased in the spleen group but the difference was not statistically significant. Median rejection-free survival was 205 days in the spleen group and 101 days in the control group (P = NS). Median length of hospital stay was 39 days in the spleen group and 61 days in the control group. With a median follow-up of 398 days (spleen group) and 1232 days (control group), 3 of 17 (17%) in the spleen group developed graft versus host disease (GVHD), whereas 1 of 23 (4.5%) in control group did (P = NS). In one patient in each group, GVHD was fatal. No patient developed posttransplant lymphoproliferative disorder (PTLD) in the spleen group, whereas 4 of 23 (17%) in the control group developed PTLD. One-year patient survival was 84% in the spleen group and 86% in the control group. Recipients of the spleen as part of a multivisceral graft had significantly lower platelet counts. Rejection-free survival may be prolonged, but the risk of GVHD may be increased.

The role of donor bone marrow infusions in withdrawal of immunosuppression in adult liver allotransplantation

We investigated the role of donor bone marrow cell (DBMC) infusions in immunosuppression withdrawal in adult liver transplantation. Patients enrolled were at least 3 years post-transplantation, with stable graft function. Forty-five (study group: G1) received DBMC, and 59 (control group: G2) did not. Immunosuppression was reduced by one third upon enrollment, by another third the second year of the study and was completely withdrawn the third year. Patient and graft survival were similar between the two groups. Although rejection episodes were significantly less in G1 the first 2 years of the study (35% vs. 57%, p = 0.016), there was no significant difference overall (74% vs. 81%, p = 0.14). Until February 2004, 20 patients, 10 in each group, were immunosuppression free for 1-3 years. Approximately 20% of long-term survivors of liver transplantation can successfully discontinue their immunosuppression. DBMC infusions, do not increase this likelihood.

Trends in serum citrulline and acute rejection among recipients of small bowel transplants

A test for detecting acute cellular rejection (ACR) of small intestinal transplants (ITx) would be a major advance. Small preliminary studies suggest that serum citrulline levels correlate with ACR. The results for a group of 26 isolated intestinal and multivisceral transplant recipients are summarized here. Serum citrulline concentrations were determined by ion exchange chromatography and compared to biopsy-based grade of ACR. Other factors considered included patient and donor age and sex, ischemia time, and serum creatinine. Straight-line fits were employed to describe how each patient's citrulline levels changed over time. Estimated times to achieve normal citrulline (>or=30 micromol/L) ranged from 1 to 730 days posttransplant for 21 patients demonstrating increasing citrulline levels over time. Using stepwise linear regression, patients' ranks for time required to achieve normal citrulline levels were the only independent predictors of both maximum ACR (P <.0001) and average ACR (P =.0059) after 14 days posttransplant. The rate and direction of change in citrulline over time may be an indicator of the risk of acute rejection. We plan to further examine the use of citrulline as a marker for rejection in larger prospective studies.

An analysis of the association between serum citrulline and acute rejection among 26 recipients of intestinal transplant

Small preliminary studies suggest that serum citrulline levels may act as a marker for acute cellular rejection in small intestinal transplant recipients. The results comparing serum citrulline concentrations with biopsy-based grades of rejection are summarized here for an expanded group of 26 isolated intestinal and multivisceral transplant recipients. Other factors considered included patient and donor age and sex, ischemia time, serum creatinine, and type of transplant. Straight-line fits reasonably described how each patient's citrulline levels changed over time. Among 21 patients who demonstrated increasing citrulline levels over time, the estimated median time-to-achieve normal citrulline (>or=30 micromol/L) was 79 days post-transplant. Using stepwise linear regression, two characteristics were associated with a significantly higher maximum grade of rejection after 14 d post-transplant: longer time-to-achieve normal citrulline (using ranks, p < 0.00001) and the patient not receiving a multivisceral transplant (p = 0.0005). Only the latter characteristic was significantly associated with maximum grade of rejection during the first 14 d post-transplant (p = 0.01). Clearly, time-to-normalization of citrulline was delayed by the incidence of rejection, and in some cases with moderate-to-severe rejection, normalization of citrulline levels never occurred. We plan to further examine the use of citrulline as a marker for rejection in larger prospective studies.

Study of the development and evolution of neointestine in a rat model

The implantation of fragmented rat intestinal epithelium into the omentum of syngeneic animals results in the formation of a cyst containing neointestine. The purpose of our project was to study the evolution of this neointestine-containing cyst over time. Harvested jejunum and ileum of neonatal DA rats (6 to 8 days old) was digested with collagenase type XI and dispase at room temperature. The resulting organoid units, containing clusters of intestinal epithelium with stem cells were seeded onto a polyglactin polymer mesh (100000 units per mesh). The absorbable mesh was implanted in the omentum or peritoneal wall of an adult syngeneic animal. Animals were sacrificed at weekly intervals to harvest the neointestinal cysts. The lumen of the neointestine cysts was full of mucous while the wall of the cyst was covered by intestinal mucosa. H&E staining of the cyst demonstrated the morphology of intestinal epithelium; PAS staining identified goblet cells. The size of the cyst was maximal between 4 and 8 weeks postimplantation tending to regress thereafter. Neointestinal cysts are a consistent finding after implantation of intestinal epithelium organoids into the omentum or peritoneal wall in the rat model. The cysts reach a maximal size at 4 to 8 weeks postimplantation, tending to regress thereafter.

Genetic susceptibility to food allergy is linked to differential TH2-TH1 responses in C3H/HeJ and BALB/c mice

BACKGROUND

Although food allergy is a serious health problem in westernized countries, factors influencing the development of food allergy are largely unknown. Appropriate murine models of food allergy would be useful in understanding the mechanisms underlying food allergy in human subjects.

OBJECTIVE

We sought to determine the susceptibility of different strains of mice to food hypersensitivity.

METHODS

C3H/HeJ and BALB/c mice were sensitized to cow's milk (CM) or peanut by means of intragastric administration, with cholera toxin as a mucosal adjuvant. Mice were then challenged with CM or peanut. Antigen-specific IgE levels, anaphylactic symptoms, plasma histamine levels, and splenocyte cytokine profiles of these 2 strains were compared.

RESULTS

CM-specific IgE levels were significantly increased only in the C3H/HeJ strain, 87% of which exhibited systemic anaphylactic reactions accompanied by significantly increased plasma histamine levels in response to challenge. BALB/c mice exhibited no significant CM-specific IgE response, increased plasma histamine levels, or anaphylactic symptoms. After peanut challenge, 100% of peanut-sensitized C3H/HeJ mice exhibited high levels of peanut-specific IgE and anaphylactic symptoms. In contrast, no hypersensitivity reactions were detected in BALB/c mice, despite the presence of significant serum peanut-specific IgE levels. Splenocytes from CM- and peanut-sensitized C3H/HeJ mice exhibited significantly increased IL-4 and IL-10 secretion, whereas splenocytes from BALB/c mice exhibited significantly increased IFN-gamma secretion.

CONCLUSION

Induction of food-induced hypersensitivity reactions in mice is strain dependent, with C3H/HeJ mice being susceptible and BALB/c mice being resistant. This strain-dependent susceptibility to food allergy is associated with differential T(H)2-T(H)1 responses after intragastric food allergen sensitization.

Murine model of atopic dermatitis associated with food hypersensitivity

BACKGROUND

Atopic dermatitis (AD) is an eczematous skin eruption that generally begins in early infancy and affects up to 12% of the population. The cause of this disorder is not fully understood, although it is frequently the first sign of atopic disease and is characterized by an elevated serum IgE level, eosinophilia, and histologic tissue changes characterized early by spongiosis and a CD4(+) T(H)2 cellular infiltrate. Hypersensitivity to foods has been implicated as one causative factor in up to 40% of children with moderate-to-severe AD.

OBJECTIVE

The purpose of this study was to establish a murine model of food-induced AD.

METHODS

Female C3H/HeJ mice were sensitized orally to cow's milk or peanut with a cholera toxin adjuvant and then subjected to low-grade allergen exposure. Histologic examination of skin lesions, allergen-specific serum Ig levels, and allergen-induced T-cell proliferation and cytokine production were examined.

RESULTS

An eczematous eruption developed in approximately one third of mice after low-grade exposure to milk or peanut proteins. Peripheral blood eosinophilia and elevated serum IgE levels were noted. Histologic examination of the lesional skin revealed spongiosis and a cellular infiltrate consisting of CD4(+) lymphocytes, eosinophils, and mast cells. IL-5 and IL-13 mRNA expression was elevated only in the skin of mice with the eczematous eruption. Treatment of the eruption with topical corticosteroids led to decreased pruritus and resolution of the cutaneous eruption.

CONCLUSION

This eczematous eruption resembles AD in human subjects and should provide a useful model for studying immunopathogenic mechanisms of food hypersensitivity in AD.

Cytokine-induced suppression and potentiation of hapten-specific immediate hypersensitivity responses

The ability of subcutaneously (s.c.) injected cytokines (IL-4, IL-5, IL-6, IFN alpha, IFN gamma, GMCSF) to regulate the induction of hapten-specific immediate hypersensitivity (IH) responses was studied in BPO-KLH (benzylpenicilloyl-keyhole limpet hemocyanin) sensitized BALB/c mice at the peak of a hapten-specific IgE antibody forming cell (AFC) response. To induce IH responses, mice were injected in the right pinna with either BPO-BSA (benzylpenicilloyl-bovine serum albumin), BPO-KLH (0.01-1.0 micrograms/ml) or mcAb anti-IgE (0.001 - 1.0 micrograms/ml); and in the left pinna with an equal volume of saline (0.05 ml). Pinnae were measured 5 min to 4 hr later using a micrometer caliper. Treatment of mice with IL-4 or IFN gamma dramatically suppressed the induction of IH responses in dose dependent fashion. In contrast, treatment of mice with IL-6 and IFN alpha increased these responses in dose dependent fashion, while GMCSF and IL-5 had no effect. The suppression obtained with IL-4 and IFN gamma, and the increases seen with IL-6 and IFN alpha, were transient since these cytokines, as well as GMCSF and IL-5, had no effect on IH responses elicited 21 days after the peak of BPO-specific IgE AFC responses. The data suggest that cytokine mediated effects on IH responses occur via changes in serum levels of BPO-specific IgG1 or IgE, through direct or indirect effects of cytokines on mast cells or other cell types, or by affecting the ability of BPO-specific homocytotropic antibodies to bind to mast cell surfaces.

A novel class of anti-DNA antibodies identified in BALB/c mice

We have characterized four IgG monoclonal antibodies (mAbs) derived from BALB/c mice that bind double-stranded DNA (dsDNA) with high affinity. The hydridomas were selected for expression of a member of the VHS107 family. Three of the four cell lines use the VH11 gene and one uses the VH1 gene. These antibodies exhibit many characteristics of pathogenic anti-DNA antibodies. They are high affinity and not broadly crossreactive. Unlike the anti-DNA antibodies in autoimmune mice, they exhibit no somatic mutation in their VH genes. These results demonstrate that somatic mutation of VHS107 genes is not necessary for generating high affinity dsDNA binding. The fact that such antibodies have not previously been reported suggests that they are rare and that their expression may be downregulated in both nonautoimmune and autoimmune individuals.

Enzyme polymorphisms as genetic signatures in human cell cultures

The electrophoretic resolution of seven relatively polymorphic human gene-enzyme systems expressed in tissue culture cells can be used as a sensitive genetic monitor for intraspecific cell contamination. An identical genotype at each of the same allozyme loci provides a 95% (or greater) confindence estimate of the identity of two cultured lines, on the basis of the allelic frequencies of the seven enzyme loci in natural populations and in populations of independently derived cultured cells. Of 27 commonly used human cell lines examined, only one of 351 pairwise comparisons proved genetically indistinguishable.