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Clinical and laboratory findings in two girls with a disorder phenotypically indistinguishable from typical X-linked agammaglobulinemia (XLA) are described. To examine the possibility that subtle defects in the X chromosome might explain the findings, detailed genetic studies were performed on one of these patients. Cytogenetic studies showed a normal 46XX karyotype. Southern blot analysis of her DNA showed that she had inherited a maternal and a paternal allele at sites flanking the locus for typical XLA at Xq22, making a microdeletion or uniparental disomy unlikely. To determine whether both of her X chromosomes could function as the active X, somatic-cell hybrids that selectively retained the active X were produced from her activated T cells. A normal random pattern of X inactivation was seen. Of 21 T-cell hybrids, 3 retained both X chromosomes, 7 had one X as the active X, and 11 had the other X as the active X. We have interpreted these studies as indicating that there is an autosomal recessive disorder that is phenotypically identical to XLA.

La/ex rubber hypersensitivity represents a significant problemfacing the medical. surgical. radiologic. and dental professions. As a tertiary care center, the Childrens Hospital of Philadelphia has a large population of patients with spina biflda and complex genitourinary anomalies; a number of these children have latex rubber allergy, which may first present as intraoperative anaphylaxis. Although there is no substitutefor complete antigen avoidance, all medical products containing latex rubber may not have suitable alternatives. Therefore. we have formulated a protocol to prevent perioperative reactions through the use of prophylactic medications and the limitation of latex exposure. This regimen includes steroids, antihistamines. and bronchodilators when indicated. In four children, prophylaxis failed peri operatively because of parenteral infusion of latex rubber proteins. (AllergyProc 13, 3:123-127,1992) C hildren with spina bifida and bladder exstrophy have been reported to have an increased risk of allergic reactions, including anaphylaxis, to natural latex rubber. )-9 Because of the potential severity of these reactions and the current lack of a proved method to identify those at risk, we formulated a preoperative medication regimen based on current recommendations for radiocontrast media (RCM) prophylaxis. 10.1 I

Immediate hypersensitivity to natural latex (NL) occurs in sensitized individuals after repeated exposure to products or devices containing NL components. Since allergic reactions to NL proteins are quite frequent and may be quite serious, diagnostic assays are needed to identify individuals at risk. A number of latex proteins have been considered the major antigens, but they have been incompletely characterized. There is no standard material available for skin testing. In vitro diagnostic tests, such as the radioallergosorbent test (RAST), are time consuming and their sensitivity and specificity remain to be proven. We have developed a rapid microsphere-based, fluorescence-activated flow cytometry assay for the measurement of NL protein-specific human immunoglobulin E and have compared it with both the enzyme-linked immunosorbent assay and radioallergosorbent test methods. By using the total purified NL protein fraction isolated from raw ammoniated NL sap as the antigen, the flow cytometry assay was both sensitive and specific for the detection of NL protein-specific human immunoglobulin E in the sera of sensitized pediatric patients.