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Biomedical subjects

Sami L Bahna

Publications and source records attributed to Sami L Bahna.

At least 19 recordsLinked to original sources
PubMed2006

Pathogenesis and recent therapeutic trends in Stevens-Johnson syndrome and toxic epidermal necrolysis.

OBJECTIVE: To review the current pathophysiologic mechanisms and recent therapeutic trends in Stevens-Johnson syndrome (SJS) and toxic epidermal necrolysis (TEN). DATA SOURCES: A MEDLINE search for SJS and TEN in combination with Fas, Fas ligand (FasL), cytotoxic T cells, intravenous immunoglobulin, and cyclosporine for articles published in English during 1966 to 2006. STUDY SELECTION: Information was derived from original research articles and reviews published in peer-reviewed journals. RESULTS: The hallmark of SJS and TEN is epidermal cell apoptosis, which may be mediated through keratinocyte Fas-FasL interaction or through cytotoxic T-cell release of perforin and granzyme B. Whereas systemic corticosteroid therapy showed contradictory results, intravenous immunoglobulin (IVIG) and cyclosporine have shown promising outcomes. IVIG contains anti-Fas antibodies that can abrogate apoptosis when preincubated with keratinocytes. Most studies on IVIG in SJS and TEN reported improvement in arresting disease progression and reduction in time to skin healing. Because of variations among studies, the findings cannot be optimally compared. In general, mortality varied from 0% to 12% in studies that supported the use of IVIG and 25% to 41.7% in those that did not demonstrate a beneficial effect. Cyclosporine inhibits CD8 activation and thus may reduce epidermal destruction. Relatively few case reports and 1 case series have been published regarding the use of cyclosporine in SJS and TEN. In general, cyclosporine was associated with a significant improvement in time to disease arrest and to complete reepithelization, with no reported fatalities. CONCLUSIONS: Both IVIG and cyclosporine have been associated with enhanced healing and better survival through inhibition of apoptosis. Multicenter, randomized, placebo-controlled trials using a standardized design are needed to validate these findings.

Adolescent↗
PubMed2006

Diagnosis of food allergy.

The diagnosis of food allergy requires obtaining a detailed medical history and consideration of differential diagnosis. The offending food(s) may be identified by the medical history, trials of elimination diets, SPT, food-specific IgE measurement, or some combination. However, the reliability of these methods is usually suboptimal, and confirmation of the offending food(s) requires well-designed challenge tests.

Antibody Specificity↗
PubMed2006

Do food or additives cause behavior disorders?

The possible role of foods or additives in causing behavioral disorders in children, particularly ADHD, has been a controversial subject both among health care providers and the public. However, a critical review of the literature provides very limited support for such a relationship. On encountering such cases, the healthcare professional should first establish an accurate diagnosis of the suspected "abnormal" behavior based on specific standard criteria. It is important to counsel the family regarding the standard of care practice and about the limited evidence of a role of foods and additives in causing behavior problems. If parents strongly suspect a specific dietary item, a trial of elimination may be warranted. If the child's behavior shows definite improvement, a challenge in a double-blind, placebo-controlled fashion under the supervision of an experienced physician would be necessary to verify the relationship.

Adolescent↗
PubMed2005

Cerebral lymphoma in an adenosine deaminase-deficient patient with severe combined immunodeficiency receiving polyethylene glycol-conjugated adenosine deaminase.

Polyethylene glycol-conjugated adenosine deaminase (PEG-ADA) provides an alternate therapy to mismatched stem cell transplantation for patients with ADA-deficient severe combined immunodeficiency. Although replacement therapy with PEG-ADA is effective in preventing infections, immune function does not return to normal, and most patients remain lymphopenic. Information is limited regarding the prognosis of patients on long-term ADA-replacement therapy. Here we present a case of a 10-year-old child who was diagnosed with ADA-severe combined immunodeficiency at 4 weeks of age after contracting pneumonia. Treatment with PEG-ADA was begun, the biochemical markers of ADA deficiency normalized, and his clinical progress was very good without significant infections. At 10 years of age, after presenting with headaches and cranial nerve deficits, he was diagnosed with Epstein-Barr virus-positive malignant brain lymphoma. It did not respond to various regimens of aggressive chemotherapy, and the patient expired 5 months later. We speculate that in this patient the immunologic surveillance by T cells may have been defective with respect to elimination of Epstein-Barr virus-infected cells, hence the formation of neoplasm. The possible mechanisms underlying such pathology are reviewed.

Adenosine Deaminase↗
PubMed2005

Skin testing versus radioallergosorbent testing for indoor allergens.

BACKGROUND: Skin testing (ST) is the most common screening method for allergy evaluation. Measurement of serum specific IgE is also commonly used, but less so by allergists than by other practitioners. The sensitivity and specificity of these testing methods may vary by type of causative allergen and type of allergic manifestation. We compared ST reactivity with serum specific IgE antibodies to common indoor allergens in patients with respiratory allergies. METHODS: 118 patients (3 mo-58 yr, mean 12 yr) with allergic rhinitis and/or bronchial asthma had percutaneous skin testing (PST) supplemented by intradermal testing (ID) with those allergens suspected by history but showed negative PST. The sera were tested blindly for specific IgE antibodies by the radioallergosorbent test (Phadebas RAST). The allergens were D. farinae (118), cockroach (60), cat epithelium (90), and dog epidermal (90). Test results were scored 0-4; ST >/= 2 + and RAST >/= 1 + were considered positive. RESULTS: The two tests were in agreement (i.e., either both positive or both negative) in 52.2% (dog epidermal) to 62.2% (cat epithelium). When RAST was positive, ST was positive in 80% (dog epidermal) to 100% (cockroach mix). When ST was positive, RAST was positive in 16.3% (dog epidermal) to 50.0% (D. farinae). When RAST was negative, ST was positive in 48.5% (cat epithelium) to 69.6% (D. farinae). When ST was negative, RAST was positive in 0% (cockroach) to 5.6% (cat epithelium). The scores of ST and RAST showed weak to moderate correlation (r = 0.24 to 0.54). Regardless of history of symptoms on exposure, ST was superior to RAST in detecting sensitization to cat epithelium and dog epidermal. CONCLUSION: For all four indoor allergens tested, ST was more sensitive than RAST. When both tests were positive, their scores showed poor correlation. Sensitizations to cat epithelium and dog epidermal are common, even in subjects who claimed no direct exposure.

Journal Article↗
PubMed2005

Pediatric food allergy update.

Food allergy is mostly a childhood disease that differs from the adult-onset allergy in several aspects, including the prevalence, commonly offending foods, symptomatology, and prognosis. The prevalence is much overestimated by the public, but it probably affects up to 6% of children. In some cases, the diagnosis might be clearly evident, but in most cases an expert evaluation may be needed that usually includes verification by challenge testing. Currently, the management of food allergy is avoidance of the offending foods together with the availability of pharmacologic agents for symptomatic treatment, including self-administered epinephrine. The latter is of utmost importance in highly allergic subjects because accidental trivial exposure is not uncommon. Recent studies promise immunomodulatory agents that might be of potential use for prophylaxis. One such agent is anti-immunoglobulin E, which might be available in the near future.

Child↗
PubMed2005

Adverse reactions to food additives.

OBJECTIVES: To summarize the literature related to the classification of food additives and their reported adverse reactions and to provide a practical approach for evaluation of patients suspected of having such reactions. DATA SOURCES: Information was derived from selected reviews and original articles published in peer-reviewed journals and from authoritative textbook chapters, supplemented by the clinical experience of the authors. STUDY SELECTION: Priority was given to studies that used blinded, placebo-controlled oral challenges to confirm adverse reactions to food additives. In addition, selected, appropriately evaluated case reports are included. RESULTS: A large number of food additives are widely used in the food industry. Adverse reactions to additives seem to be rare but are likely underdiagnosed in part due to a low index of suspicion. Numerous symptoms have been attributed to food additive exposure, but the cause-and-effect relationship has not been well demonstrated in all. CONCLUSIONS: Reactions to food additives should be suspected in patients who report symptoms to multiple unrelated foods or to a certain food when commercially prepared but not when homemade and the allergy evaluation rules out a role for food protein. It is also prudent to investigate food additives in patients considered to have idiopathic reactions. There is a minor role for skin testing or in vitro testing. Oral challenge testing with common additives, preferably preceded by a trial of an additive-free diet, is the definitive procedure for detecting the offending agent. Once the specific additive is identified, management is basically avoidance of all its forms.

Allergens↗
PubMed2005

Milk-induced pulmonary disease in infants (Heiner syndrome).

Heiner syndrome (HS) is a food hypersensitivity pulmonary disease that affects primarily infants, and is mostly caused by cow's milk (CM). Only a few reports have been published, which may be due to its misdiagnosis. We review here a series of eight cases. When first diagnosed they were 4-29 months of age. They were fed CM from birth and their chronic respiratory symptoms began at age 1-9 months. The symptoms were in the form of cough in seven, wheezing in three, hemoptysis in two, nasal congestion in three, dyspnea in one, recurrent otitis media (OM) in three, recurrent fever in four, anorexia, vomiting, colic or diarrhea in five, hematochezia in one, and failure to thrive (FTT) in two. All had radiologic evidence of pulmonary infiltrates. High titers of precipitating antibodies to CM proteins were demonstrated in six of six and milk-specific immunoglobulin E (IgE) was positive in one of two. Pulmonary hemosiderosis (PH) was confirmed in one patient who showed iron-laden macrophages (ILM) in the bronchoalveolar lavage (BAL), gastric washing, and open lung biopsy. Additional findings, in a descending frequency, were eosinophilia, anemia, and elevated level of total IgM, IgE or IgA. Milk elimination resulted in remarkable improvement in symptoms within days and clearing of the pulmonary infiltrate within weeks. Parents consented to milk challenge in only three cases, all of whom developed recurrence of symptoms. After 2 yr of milk avoidance in one patient, milk challenge was tolerated for 2 months, and then the patient developed symptoms, serum milk precipitins, pulmonary infiltrate, and ILM. The HS should be suspected in young children with chronic pulmonary disease of obscure cause. The diagnosis is supported with a positive milk precipitin test and improvement on a trial of milk elimination. Severe cases may be complicated with PH, which should be suspected in the presence of anemia or hemoptysis and be confirmed with the demonstration of ILM.

Antibody Specificity↗
PubMed2003

Clinical expressions of food allergy.

BACKGROUND: The perception, by both the public and health professionals, of the clinical expressions of food allergy (FA) varies widely, from one extreme of nonexistence to another extreme of causing almost every ailment. Critical investigations in recent years led to a better clarification, as well as a reasonable classification, of FA manifestations. OBJECTIVE: To provide a differential diagnosis of adverse reactions to foods and a classification of well proven FA manifestations. DATA SOURCES: Reviews and original articles published in peer-reviewed journals, as well as classic textbooks on FA. RESULTS: FA can affect several body systems. The gastro-intestinal tract is probably the most affected organ, but it does not always exhibit overt symptoms. Cutaneous manifestations are next in frequency, and in some studies are the most frequent perhaps because they are visible. Respiratory symptoms as sole manifestations of FA are less common, but have high frequency in children with atopic dermatitis. Systemic anaphylaxis has been responsible for sudden fatalities, although the exposure was often to minute quantities of the offending food. Other rare manifestations have been reported and are probably underdiagnosed. CONCLUSIONS: FA is defined as the immunologically mediated adverse reactions to foods. It can be expressed in a wide array of clinical manifestations, ranging from simple gastro-intestinal, cutaneous, or respiratory symptoms to fatal anaphylaxis. Studies are needed to verify some rare or anecdotal manifestations that have been reported but are still considered controversial.

Diagnosis, Differential↗
PubMed2003

Diagnosis of food allergy.

BACKGROUND: Food allergy is gaining substantial interest by both the public and health professionals. It is usually overdiagnosed by the public and misdiagnosed by physicians. OBJECTIVE: To provide an outline for appropriate evaluation of patients suspected of having food allergy. DATA SOURCES: Information was derived from selected review and original articles published in peer-reviewed journals and from authoritative textbook chapters, supplemented by the clinical experience of the author. RESULTS: Several approaches have been used for food allergy diagnosis, including the medical history, trials of elimination diets, food/symptom diary, skin testing, in vitro tests, and oral challenges. In most cases, the medical history is inconclusive and the reliability of the in vivo and in vitro tests is suboptimal. Appropriately designed challenge testing remains the gold standard, although it has a few limitations. CONCLUSIONS: Appropriate selection, application, and interpretation of tests for food allergy are necessary for attaining a high degree of accuracy of diagnosis.

Diagnosis, Differential↗
PubMed2002

Innate immunity and its role against infections.

LEARNING OBJECTIVES: This article reviews current concepts of the innate immune system that offers protection against infections. It offers an overview for the readers to understand how innate immunity, consisting of different receptors, cells, and mediators recognizes pathogens and exerts protective function against pathogens. DATA SOURCES AND STUDY SELECTION: MEDLINE-search articles including original research papers, review articles, textbooks, and references identified from bibliographies of relevant articles. RESULTS AND CONCLUSIONS: The innate immune system is nonspecific immunity present since birth not requiring repeated exposure to pathogens. It is capable of differentiation between self and nonself. Because of its nonspecificity, it has a broad spectrum of resistance to infection. Further, it is thought to play an important role in the control of adaptive immunity by regulating co-stimulatory molecules and effector cytokines. Innate immunity includes pattern recognition molecules/receptors, antimicrobial peptides, the complement system, inflammatory mediators, and cytokines produced by immune cells. Pattern recognition molecules/receptors recognize pathogen-associated molecular patterns that are essential for microorganisms' survival and pathogenicity. Although innate immunity has recently gained increasing importance, further studies are necessary for a better understanding of its role.

Animals↗
PubMed2002

Cow's milk allergy versus cow milk intolerance.

BACKGROUND: Although cow's milk allergy (CMA) and cow's milk intolerance (CMI) are two different terms, they are often used interchangeably, resulting in confusion both in clinical practice and in research reports. OBJECTIVE: To promote the appropriate differential use of the terms CMA and CMI. METHODS: Highlighting the differences in clinical and laboratory findings between CMA and CMI. Information was derived from reviewing the literature on these two topics, supplemented by the clinical experience of the author. RESULTS: CMA is an immunologically mediated reaction to cow's milk proteins that may involve the gastro-intestinal tract, skin, respiratory tract, or multiple systems, ie, systemic anaphylaxis. Its prevalence in the general population is probably 1 to 3%, being highest in infants and lowest in adults. Even though it can cause severe morbidity and even fatality, dietary elimination is associated with good prognosis. However, CMI should refer to nonimmunologic reactions to cow's milk (CM), such as disorders of digestion, absorption, or metabolism of certain CM components. The most common cause of CMI is lactase deficiency, which is mostly acquired during late childhood or adulthood. It has high racial predilection, being highest in dark-skinned populations and lowest in northern Europeans. Lactose intolerance is generally a benign condition, with symptoms limited to the gastro-intestinal tract, yet the primary acquired type lasts for a lifetime. Symptoms can be well ameliorated by reducing the intake of CM or using lactose-hydrolyzing agents. CONCLUSIONS: Adverse reactions to CM should be differentiated into immunologic (CMA) and nonimmunologic (CMI). The latter is still a general term that comprises several conditions and requires further differentiation.

Allergens↗
PubMed2002

Severe food-induced vasculitis in two children.

Food-induced vasculitis seems to be rare and is considered by some as controversial. The reported cases in the literature are few and mostly on adult patients. Described in this report are two children with severe vasculitis caused by specific foods. They were diagnosed at two separate allergy centers that have a special interest in food allergies. Case 1 was an 8-year-old girl with a 9-month history of cutaneous vasculitis with large joints involvement. Case 2 was a 23-month-old girl with an 8-month history of multiple hospitalizations for recurrent acute severe cutaneous and mucous membrane vasculitis with large joints involvement. In both patients, skin biopsy showed leucocytoclastic vasculitis. In neither of the patients could the symptoms be attributed to drug intake, infection, autoimmunity, or other systemic disease. Case 1 had a moderately elevated serum total immunoglobulin E (IgE) level and strongly positive skin test and radioallergosorbent test (RAST) to cow's milk and hen's egg, both of which were proven to be the cause by elimination-challenge tests. Case 2 had a slightly elevated serum total IgE level, but negative skin tests to foods, including chocolate that was suspected by the mother. Avoidance of chocolate resulted in remission, except following accidental ingestion of cocoa-containing products. These findings support the few previous reports on food-induced vasculitis, an entity that seems rare but may be more common than currently realized.

Child↗