Search

Only some allergists/immunologists provide care throughout the lifespan despite their training. Although transition of care (TOC) guidelines exist, research on provider perspectives on TOC for pediatric primary immunodeficiency (PID) patients is lacking. We aimed to characterize knowledge, attitudes, and practices and establish clinician needs using a needs assessment survey.The 15-min online survey was adapted from an existing rheumatology TOC survey and was emailed to the American Academy of Allergy Asthma and Immunology (AAAAI) and Clinical Immunology Society (CIS) members. Our primary hypothesis was that both AAAAI and CIS providers report being underprepared for TOC and would express interest in TOC resources and consensus.Forty-nine of 1250 eligible AAAAI and 67 of 698 eligible CIS participants completed the survey (4.8% vs 11.3% participation rate). Many (53.1% vs 59.7%) respondents transition their own patients but also retain adult patients (59.2% vs 52.2%). Many accepted transition patients (85.7% vs 92.5%). In total, 24.1% of respondents did not have a TOC policy while 18.9% have an informal policy. Only 25.0% were satisfied with their current practices while 43.9% agreed that a consensus statement would be useful.Despite a small sample size and high rate of unanswered questions, our findings show that TOC remains overlooked in our specialty and that providers want and need additional training and resources. There is a clear need to develop and evaluate the effectiveness of evidence-based TOC guidelines, resources, and best practices for PID patients.

Newborn screening (NBS) quantifies T cell receptor excision circles (TREC) and identifies infants with T cell lymphopenia (TCL). This study elucidates the demographics, laboratory characteristics, genetics, and clinical outcomes following live viral vaccine administration of term infants with transient or persistent idiopathic TCL. A single-center retrospective analysis was performed from September 2010 through June 2018. Laboratory variables were compared with Mann-Whitney tests. Correlations between initial TREC levels and T cell counts were determined by Spearman tests. Twenty-two transient and 21 persistent TCL infants were identified. Males comprised 68% of the transient and 52% of the persistent TCL cohorts. Whites comprised 23% of the transient and 29% of the persistent cohorts. Median initial TREC levels did not differ (66 vs. 60 TRECs/μL of blood, P = 0.58). The transient cohort had higher median initial CD3+ (2135 vs. 1169 cells/μL, P

Health-related quality of life (HRQOL) is an emerging topic of interest in patients with immunodeficiency. Information about HRQOL in common variable immunodeficiency (CVID) is limited. The primary objective was to compare primary immunodeficiency disease (PIDD) patients with and without common variable immunodeficiency (CVID) on HRQOL domains using Patient-Reported Outcomes Measurement Information System (PROMIS-29) survey data from the United States Immunodeficiency Network (USIDNET) registry. The primary endpoint variables were scores on 7 HRQOL domains. The USIDNET registry was used to select patients with baseline PROMIS-29 data collected between 2015 and 2018. Descriptive statistics, Fisher's exact test, and Student's two-sample t test were used to compare patients with CVID versus patients with non-CVID on demographic and clinical characteristics. The single-sample t test was used to compare sample means to the normed population mean of 50. A general linear model approach to multiple regression with backward selection was used to remove factors that did not contribute significant information to the multivariable models, while controlling for multiple testing. Potential explanatory variables included group (CVID/non-CVID), sex, age, and BMI. Among 184 PIDD patients, 146 (79%) were diagnosed with CVID. Patients had a mean (SD) age of 53 (13.8), were predominantly female (83%), and were Caucasian (98%). PROMIS-29 results revealed a significant effect of group (CVID/non-CVID) on the anxiety, fatigue, and social participation domains, with fatigue being the most statistically significant. Fatigue, anxiety, and social participation may be key factors influencing HRQOL among patients with CVID. Future prospective longitudinal studies using PROMIS-29 will be needed to confirm these findings and to determine the mechanisms through which these factors develop in CVID, and how they can be improved.

Genetic testing has become an integral component of the diagnostic evaluation of patients with suspected primary immunodeficiency diseases. Results of genetic testing can have a profound effect on clinical management decisions. Therefore clinical providers must demonstrate proficiency in interpreting genetic data. Because of the need for increased knowledge regarding this practice, the American Academy of Allergy, Asthma & Immunology Primary Immunodeficiency Diseases Committee established a work group that reviewed and summarized information concerning appropriate methods, tools, and resources for evaluating variants identified by genetic testing. Strengths and limitations of tests frequently ordered by clinicians were examined. Summary statements and tables were then developed to guide the interpretation process. Finally, the need for research and collaboration was emphasized. Greater understanding of these important concepts will improve the diagnosis and management of patients with suspected primary immunodeficiency diseases.

Anaphylaxis in the elderly is poorly understood.To elucidate demographic, clinical, and management characteristics of older adults presenting to emergency departments (EDs) with National Institute of Allergy and Infectious Diseases (NIAID) criteria-confirmed anaphylaxis vs milder, non-anaphylactic acute allergic reactions (AARs).A retrospective analysis of ED patients more than or equal to 65 years was conducted, using anaphylaxis International Classification of Diseases, Ninth Revision (ICD-9) codes or ICD-9-based algorithms incorporating the NIAID diagnostic criteria. Descriptive statistics were generated, and the abovementioned characteristics were compared between cohorts.Of 164 eligible visits, 71 (43.3%), 90 (54.9%), and 3 (1.8%) cases were identified by ICD-9 codes, the algorithms, or both, respectively. Only half fulfilled NIAID diagnostic criteria. Compared with the non-anaphylactic AAR group, criteria-confirmed anaphylaxis group had lower drug allergy rates (43.9% vs 61.0%, P = .03) but higher food allergy rates (26.8% vs 12.2%, P = .02). For the criteria-confirmed anaphylaxis group, presenting signs and symptoms in descending frequency were mucocutaneous, respiratory, cardiovascular, and gastrointestinal. Criteria-confirmed anaphylaxis group had higher rates of prior anaphylaxis (13.4% vs 2.4%, P = .009), pre-ED (12.2% vs 0.0%, P = .001) or ED (72.0% vs 4.9%, P.001) epinephrine administration, and allergy referral (17.1% vs 2.4%, P = .002). Tryptase levels were rarely ordered, occurring once in the criteria-confirmed anaphylaxis group and never in the non-anaphylactic AAR group. Despite low mortality (n = 1), 64.6% of the criteria-confirmed anaphylaxis cohort required hospitalization, with 23.2% admitted to intensive care unit.Diagnosis of elderly ED patients with anaphylaxis remains suboptimal. Identifying NIAID criteria-confirmed cases remain challenging, using the existing methods. Management of these patients poorly adheres to current guidelines.

Secondary hypogammaglobulinemia (SHG) is characterized by reduced immunoglobulin levels due to acquired causes of decreased antibody production or increased antibody loss. Clarification regarding whether the hypogammaglobulinemia is secondary or primary is important because this has implications for evaluation and management. Prior receipt of immunosuppressive medications and/or presence of conditions associated with SHG development, including protein loss syndromes, are histories that raise suspicion for SHG. In patients with these histories, a thorough investigation of potential etiologies of SHG reviewed in this report is needed to devise an effective treatment plan focused on removal of iatrogenic causes (eg, discontinuation of an offending drug) or treatment of the underlying condition (eg, management of nephrotic syndrome). When iatrogenic causes cannot be removed or underlying conditions cannot be reversed, therapeutic options are not clearly delineated but include heightened monitoring for clinical infections, supportive antimicrobials, and in some cases, immunoglobulin replacement therapy. This report serves to summarize the existing literature regarding immunosuppressive medications and populations (autoimmune, neurologic, hematologic/oncologic, pulmonary, posttransplant, protein-losing) associated with SHG and highlights key areas for future investigation.

Background: Allergic and nonallergic adverse reactions have been reported with global coronavirus disease 2019 (COVID-19) vaccination. It was previously hypothesized that polyethylene glycol (PEG) may be responsible for anaphylactic reactions to mRNA COVID-19 vaccines. Objective: To report the workflow established at our institution, types, and frequency of adverse reactions to mRNA COVID-19 vaccines in patients presenting for allergy evaluation. Methods: A COVID-19 vaccines adverse reactions registry was established. We used PEG prick skin testing, followed by PEG challenges in selected cases, to ensure PEG tolerance and encourage completion of COVID-19 vaccination series. Results: A total of 113 patients were included. Most vaccine reactions (86.7%) occurred in women. Anaphylaxis occurred only in women, all of which had a history of allergic disease and two-thirds had asthma. Anaphylaxis rate was 40.6 cases per million. None of the anaphylactic cases developed hypotension, required intubation or hospital admission. Systemic allergic symptoms, not fulfilling anaphylaxis criteria were significantly more common in Pfizer-BioNTech than Moderna vaccinated patients (p=0.02). We observed a higher incidence of dermatologic non-urticarial reactions in men (p=0.004). Among first dose reactors, 86.7% received and tolerated second dose. We observed a high rate of false positive intradermal skin tests and frequent subjective symptoms with oral PEG challenge. Conclusion: Intradermal PEG testing has limited utility in evaluating anaphylaxis to mRNA vaccines. Most severe postvaccination allergic symptoms are not caused by hypersensitivity to PEG. The majority of people with reaction to the initial mRNA vaccine can be safely revaccinated. Patients with anaphylaxis to COVID-19 vaccines benefit from physician-observed vaccination.

Background Although fever is considered a sign of infection, many individuals with primary immunodeficiency (PI) anecdotally report a lower-than-normal average body temperature on online forums sponsored by the Immune Deficiency Foundation (IDF). There is limited knowledge about the average body temperature and fever response in PI. Objective This study aims to compare median body temperatures between adults with and without PI diagnoses living in the same household and to engage individuals living with PI throughout the research process. Methods Patients with PI designed and launched a prospective cohort comparison study as citizen scientists. A multidisciplinary team designed and implemented a patient-informed study with continuous patient-driven input. Median body temperatures were compared between the 2 cohorts using the Mann-Whitney test with Bonferroni correction. The IDF conducted a post-study patient experience survey. Results Data from 254 households were analyzed (254/350, 72.6% participation rate). The PI population was predominantly female (218/254, 85.8%), White (248/254, 97.6%), and with a median age of 49 years. The non-PI population was largely male (170/254, 66.9%), White (236/254, 92.9%), and with a median age of 53 years. Common variable immunodeficiency was the most common PI diagnosis (190/254, 74.8%). Of the 254 individuals with PI, 123 (48.4%) reported a lower-than-normal nonsick body temperature, whereas 108 (42.5%) reported a normal (between 97°F and 99°F) nonsick body temperature. Among individuals with PI, when infected, 67.7% (172/254) reported the absence of fever, whereas 19.7% (50/254) reported a normal fever response. The recorded median body temperature was minimally but statistically significantly higher for patients with PI in the morning. Although 22.4% (57/254) of patients with PI self-reported illness, a fever of 100.4°F or higher was uncommon; 77.2% (196/254) had a normal temperature (between 97°F and 99°F), and 16.2% (41/254) had a lower-than-normal temperature (between 95.0°F and 96.9°F) when sick. For these sick patients with PI, the median body temperature was minimally but statistically significantly higher for patients in the morning and early evening. Overall, 90.9% (231/254) of participants would be very likely to participate in future IDF studies, although 94.1% (239/254) participants had never taken part in previous studies. Conclusions To our knowledge, this is the first study to evaluate average body temperature in individuals with PI. Although there were small statistically significant differences in body temperatures between PI and non-PI subjects, the clinical significance is unclear and should be interpreted with caution, given the methodological issues associated with our small convenience sample and study design. As PIs are heterogeneous, more research is needed about how the fever response differs among diverse PIs compared with healthy controls. This study highlights that individuals with PI are knowledgeable about their health and can offer unique insights and direction to researchers and clinicians.

BACKGROUND Although fever is considered a sign of infection, many individuals with primary immunodeficiency (PI) anecdotally report a lower-than-normal average body temperature on online forums sponsored by the Immune Deficiency Foundation (IDF). There is limited knowledge about the average body temperature and fever response in PI. OBJECTIVE This study aims to compare median body temperatures between adults with and without PI diagnoses living in the same household and to engage individuals living with PI throughout the research process. METHODS Patients with PI designed and launched a prospective cohort comparison study as citizen scientists. A multidisciplinary team designed and implemented a patient-informed study with continuous patient-driven input. Median body temperatures were compared between the 2 cohorts using the Mann-Whitney test with Bonferroni correction. The IDF conducted a post-study patient experience survey. RESULTS Data from 254 households were analyzed (254/350, 72.6% participation rate). The PI population was predominantly female (218/254, 85.8%), White (248/254, 97.6%), and with a median age of 49 years. The non-PI population was largely male (170/254, 66.9%), White (236/254, 92.9%), and with a median age of 53 years. Common variable immunodeficiency was the most common PI diagnosis (190/254, 74.8%). Of the 254 individuals with PI, 123 (48.4%) reported a lower-than-normal nonsick body temperature, whereas 108 (42.5%) reported a normal (between 97°F and 99°F) nonsick body temperature. Among individuals with PI, when infected, 67.7% (172/254) reported the absence of fever, whereas 19.7% (50/254) reported a normal fever response. The recorded median body temperature was minimally but statistically significantly higher for patients with PI in the morning. Although 22.4% (57/254) of patients with PI self-reported illness, a fever of 100.4°F or higher was uncommon; 77.2% (196/254) had a normal temperature (between 97°F and 99°F), and 16.2% (41/254) had a lower-than-normal temperature (between 95.0°F and 96.9°F) when sick. For these sick patients with PI, the median body temperature was minimally but statistically significantly higher for patients in the morning and early evening. Overall, 90.9% (231/254) of participants would be very likely to participate in future IDF studies, although 94.1% (239/254) participants had never taken part in previous studies. CONCLUSIONS To our knowledge, this is the first study to evaluate average body temperature in individuals with PI. Although there were small statistically significant differences in body temperatures between PI and non-PI subjects, the clinical significance is unclear and should be interpreted with caution, given the methodological issues associated with our small convenience sample and study design. As PIs are heterogeneous, more research is needed about how the fever response differs among diverse PIs compared with healthy controls. This study highlights that individuals with PI are knowledgeable about their health and can offer unique insights and direction to researchers and clinicians.

Limited information is available on the effect of anaphylaxis, a severe, potentially life-threatening allergic reaction, in the elderly population.To elucidate the frequency of anaphylaxis and the demographic characteristics of elderly patients admitted to New York hospitals from 2000 to 2010.A retrospective analysis of hospitalized patients aged 65 years and older in New York from 2000 to 2010 was conducted using the Statewide Planning and Research Cooperative System, a statewide administrative database. Cases were identified using anaphylaxis International Classification of Diseases, Ninth Revision (ICD-9) codes or an ICD-9-based diagnostic algorithm incorporating the National Institutes of Allergy and Infectious Disease diagnostic criteria. The χA total of 3673 hospitalizations were analyzed. Anaphylaxis ICD-9 codes identified 1790 cases (48.7%), the algorithms identified 1701 cases (46.3.%), and 182 cases (5.0%) were identified by both. Hospitalization rates increased significantly during this period (P.001). Women comprised 61.5% and people of white race comprised 69.8% of the sample. Distribution by age differed by ascertainment method (ICD-9 vs algorithm) among the early-old group (65-74 years of age; 53.8% vs 41.8%) and among the late-old group (≥85 years of age; 11.2% vs 19.3%).Hospitalization rates and anaphylaxis cases increased during the study period among the hospitalized elderly population of New York. Relying on anaphylaxis ICD-9 codes alone missed approximately half of possible cases. The identification and possibly the effect of anaphylaxis among the elderly population may differ, depending on age, race, payer, New York County, and disposition.

BACKGROUND: Allergic and nonallergic adverse reactions have been reported with global coronavirus disease 2019 (COVID-19) vaccination. It was previously hypothesized that polyethylene glycol (PEG) may be responsible for anaphylactic reactions to messenger RNA (mRNA) COVID-19 vaccines. OBJECTIVE: To report the workflow established at our institution, types, and frequency of adverse reactions to mRNA COVID-19 vaccines in patients presenting for allergy evaluation. METHODS: A COVID-19 vaccine adverse reaction registry was established. We used PEG prick skin testing, followed by PEG challenges in selected cases, to ensure PEG tolerance and encourage completion of COVID-19 vaccination series. RESULTS: A total of 113 patients were included. Most vaccine reactions (86.7%) occurred in women. Anaphylaxis occurred only in women, all of which had a history of allergic disease and two-thirds had asthma. Anaphylaxis rate was 40.6 cases per million. None of the anaphylactic cases developed hypotension, required intubation, or required hospital admission. Systemic allergic symptoms, not fulfilling anaphylaxis criteria, were significantly more common in Pfizer-BioNTech than Moderna-vaccinated patients (P = .02). We observed a higher incidence of dermatologic nonurticarial reactions in men (P = .004). Among first-dose reactors, 86.7% received and tolerated the second dose. We observed a high rate of false-positive intradermal skin test results and frequent subjective symptoms with oral PEG challenge. CONCLUSION: Intradermal PEG testing has limited utility in evaluating anaphylaxis to mRNA vaccines. Most severe postvaccination allergic symptoms are not caused by hypersensitivity to PEG. Most people with reaction to the initial mRNA vaccine can be safely revaccinated. Patients with anaphylaxis to COVID-19 vaccines benefit from physician-observed vaccination.

Chronic granulomatous disease (CGD) is a rare primary immunodeficiency that is caused by defects in the nicotinamide adenine dinucleotide phosphate (NADPH) oxidase complex. The disease presents in most patients initially with infection, especially of the lymph nodes, lung, liver, bone, and skin. Patients with CGD are susceptible to a narrow spectrum of pathogens, and Staphylococcus aureus, Burkholderia cepacia complex, Serratia marcescens, Nocardia species, and Aspergillus species are the most common organisms implicated in North America. Granuloma formation, most frequently in the gastrointestinal and genitourinary systems, is a common complication of CGD and can be seen even before diagnosis. An increased incidence of autoimmune disease has also been described in patients with CGD and X-linked female carriers. In patients who present with signs and symptoms consistent with CGD, a flow cytometric dihydrorhodamine neutrophil respiratory burst assay is a quick and cost-effective way to evaluate NADPH oxidase function. The purpose of this review is to highlight considerations for and challenges in the diagnosis of CGD.

Introduction Most states use T-Cell Receptor Excision Circle (TREC) assays in routine newborn screening to identify infants with T cell defects. Some of these low TREC infants have normal T cell counts and function, without evidence of clinically significant disease. However, some of these low TREC infants without evidence of T cell dysfunction may develop serious infections, necessitating further immune evaluation. Case Description We present two infants whose initial newborn screens were flagged for low TREC numbers but had normal T cell number and function on further evaluation. These infants had significant infectious history – Patient 1 was an ex-36 week gestational age female who had necrotizing enterocolitis and intraabdominal abscess requiring resection, while Patient 2 was a term female who had streptococcal bacteremia leading to shock soon after birth, E. Coli tracheitis and recurrent ear infections in the first year of life. Further evaluation demonstrated complement deficiecy, in both – Patient 1 had low Mannose Bending lectin, while Patient 2 had low AH50 and properidin. Discussion These infants highlight the importance of using clinical history to guide the medical testing for all patients. Although both infants had low TRECs on their newborn screens, this could have been related to stress from their initial illness. The low TREC referral facilitated timely evaluation by clinical immunologists, even though their ultimate immunodefiency was in another arm of the immune system. An unintended consequence of routine TREC newborn screening may be earlier identification of primary immunodeficiency patients with non-T cell defects.

Newborn screening for SCID has revealed the association of low T cells with a number of unexpected syndromes associated with low T cells, some of which were not appreciated to have this feature. This review will discuss diagnostic approaches and the features of some of the syndromes likely to be encountered following newborn screening for immune deficiencies.

Physicians underrecognize and undertreat anaphylaxis. Effective interventions are needed to improve physician knowledge and competency regarding evidence-based anaphylaxis diagnosis and management (ADAM). We designed and evaluated an educational program to improve ADAM in pediatrics, internal medicine, and emergency medicine residents from two academic medical centers. Anonymous questionnaires queried participants’ demographics, prior ADAM clinical experience, competency, and comfort. A pretest assessing baseline knowledge preceded a 45-minute allergist-led evidence-based presentation, including practice with epinephrine autoinjectors, immediately followed by a posttest. A follow-up test assessed long-term knowledge retention twelve weeks later. 159 residents participated in the pretest, 152 participated in the posttest, and 86 participated in the follow-up test. There were no significant differences by specialty or site. With a possible score of 10, the mean pretest score (7.31 ± 1.50) was lower than the posttest score (8.79 ± 1.29) and follow-up score (8.17 ± 1.72) (P<0.001 for both). Although participants’ perceived confidence in diagnosing or managing anaphylaxis improved from baseline to follow-up (P<0.001 for both), participants’ self-reported clinical experience with ADAM or autoinjector use was unchanged. Allergist-led face-to-face educational intervention improves residents’ short-term knowledge and perceived confidence in ADAM. Limited clinical experience or reinforcement contributes to the observed decreased knowledge.

Purpose: Melanin has emerged as an attractive target for radioimmunotherapy (RIT) of melanoma, and a radiolabeled monoclonal antibody (mAb) 6D2 to melanin is currently in clinical evaluation. We investigated two approaches to improve the targeting of radiation to tumors using melanin-binding mAbs: (a) the use of an additional mAb to melanin could provide information on whether using antibodies to melanin can serve as a general approach to development of therapeutics for melanoma, and (b) as melanin targeting involves the antibody binding to extracellular melanin released from necrotic melanoma cells, we hypothesized that the administration of a chemotherapeutic agent followed by RIT would facilitate the delivery of radiation to the tumors due to the increased presence of free melanin. Experimental Design: We evaluated the therapeutic efficacy of two melanin-binding IgM mAbs labeled with 188Re (6D2 and 11B11). We compared the efficacy of RIT with 188Re-6D2 to chemotherapy with dacarbazine (DTIC) and to combined chemotherapy and RIT in human metastatic melanoma-bearing nude mice. Results: Therapeutic efficacy of 188Re-labeled 6D2 and 11B11 was comparable despite differences in their affinity and binding site numbers. Comparison of chemotherapy with DTIC and RIT revealed that RIT was more effective in slowing tumor growth in mice. Administration of DTIC followed by RIT was more effective than either modality alone. Conclusions: These results provide encouragement for the development of RIT for melanoma with melanin-binding mAbs and suggest that combining chemotherapy and RIT may be a promising approach for the treatment of metastatic melanoma.

The rodent malaria Plasmodium yoelii is a useful model to study protective immunity to pre-erythrocytic stages of infection, pathogenesis of erythrocytic stages, and vaccine development. However, the utility of the P. yoelii model system has not been fully realized because transfection and genetic manipulation methodologies for this rodent species are less developed than that of another rodent species Plasmodium berghei. Here we report improved transfection efficiency using the AMAXA nucleofector system compared to conventional transfection methodologies. We also show that heterologous promoters from P. berghei can be used to drive expression of a green fluorescent protein (GFP) reporter protein in P. yoelii. In an effort to develop additional selectable markers for this parasite, we also tested positive selectable markers that have been used successfully in P. falciparum and P. berghei. Human dihydrofolate reductase (hdhfr) and Toxoplasma gondii dihydrofolate reductase-thymidylate synthase (Tgdhfr-ts) conferred drug resistance to WR99210 and pyrimethamine, respectively, when introduced as episomes. These improvements should make genetic manipulation of P. yoelii more amenable and facilitate further studies of host-parasite interactions using this attractive rodent model.

Apical membrane antigen-1 (AMA1) is a conserved apicomplexan protein that plays an important but undefined role in host cell invasion. We have studied the fate of Plasmodium falciparum AMA1 (PfAMA1) during erythrocyte invasion by the malaria merozoite, and compared it with that of the Toxoplasma gondii orthologue, TgAMA1. Shedding of the PfAMA1 ectodomain goes essentially to completion during invasion, and occurs predominantly or exclusively via juxtamembrane cleavage at the previously identified sheddase cleavage site, Thr517. Only the resulting juxtamembrane stub of the ectodomain is efficiently carried into the host cell, and this remains distributed around the plasma membrane of the intracellular ring-stage parasite. Inhibition of normal shedding, however, results in proteolysis at an intramembrane, rhomboid-like cleavage site, and PfAMA1 is susceptible to cleavage by Drosophila rhomboid-1, showing that it can be a substrate for intramembrane cleavage but is not normally processed in this manner. In contrast, shedding of TgAMA1 from the surface of extracellular tachyzoites occurs exclusively via cleavage within the luminal half of its transmembrane domain by a rhomboid-like protease. Also unlike PfAMA1, complete TgAMA1 shedding does not accompany Toxoplasma invasion as the intact protein was readily detected on the surface of newly invaded tachyzoites. This work reveals unexpected differences in the manner in which Plasmodium and Toxoplasma shed AMA1 from the surface of invasive zoites, and demonstrates the presence at the malaria merozoite surface of a rhomboid-like protease.

Many intracellular pathogens are separated from the cytosol of their host cells by a vacuole membrane. This membrane serves as a critical interface between the pathogen and the host cell, across which nutrients are imported, wastes are excreted, and communication between the two cells takes place. Very little is known about the vacuole membrane proteins mediating these processes in any host-pathogen interaction. During a screen for monoclonal antibodies against novel surface or secreted proteins ofToxoplasma gondii, we identified ROP4, a previously uncharacterized member of the ROP2 family of proteins. We report here on the sequence, posttranslational processing, and subcellular localization of ROP4, a type I transmembrane protein. Mature, processed ROP4 is localized to the rhoptries, secretory organelles at the apical end of the parasite, and is secreted from the parasite during host cell invasion. Released ROP4 associates with the vacuole membrane and becomes phosphorylated in the infected cell. Similar results are seen with ROP2. Further analysis of ROP4 showed it to be phosphorylated on multiple sites, a subset of which result from the action of either host cell protein kinase(s) or parasite kinase(s) activated by host cell factors. The localization and posttranslational modification of ROP4 and other members of the ROP2 family of proteins within the infected cell make them well situated to play important roles in vacuole membrane function.

Pneumocystis jirovecii pneumonia is an opportunistic pulmonary infection usually associated with T-cell defects. Clinical and murine studies demonstrate that B-cells and Pneumocystis-specific antibodies also contribute to effective immune responses.1 Patients with primary humoral immunodeficiencies, including X-linked agammaglobulinemia (XLA), may develop P . jirovecii pneumonia despite normal T-cell number and function.2,3 XLA arises from Bruton tyrosine kinase (BTK) gene mutations, leading to pre-B-cell differentiation arrest, absence of immunoglobulin expression, and increased susceptibility to bacterial/enteroviral infections.4 Although more than 600 BTK mutations have been described, new variations/mutations continue to be identified. We describe an infant with a novel BTK kinase domain variation who presented with polymicrobial pneumonia, including P. jirovecii.

Apical membrane antigen-1 (AMA1) is a conserved apicomplexan protein that plays an important but undefined role in host cell invasion. We have studied the fate of Plasmodium falciparum AMA1 (PfAMA1) during erythrocyte invasion by the malaria merozoite, and compared it with that of the Toxoplasma gondii orthologue, TgAMA1. Shedding of the PfAMA1 ectodomain goes essentially to completion during invasion, and occurs predominantly or exclusively via juxtamembrane cleavage at the previously identified sheddase cleavage site, Thr517. Only the resulting juxtamembrane stub of the ectodomain is efficiently carried into the host cell, and this remains distributed around the plasma membrane of the intracellular ring-stage parasite. Inhibition of normal shedding, however, results in proteolysis at an intramembrane, rhomboid-like cleavage site, and PfAMA1 is susceptible to cleavage by Drosophila rhomboid-1, showing that it can be a substrate for intramembrane cleavage but is not normally processed in this manner. In contrast, shedding of TgAMA1 from the surface of extracellular tachyzoites occurs exclusively via cleavage within the luminal half of its transmembrane domain by a rhomboid-like protease. Also unlike PfAMA1, complete TgAMA1 shedding does not accompany Toxoplasma invasion as the intact protein was readily detected on the surface of newly invaded tachyzoites. This work reveals unexpected differences in the manner in which Plasmodium and Toxoplasma shed AMA1 from the surface of invasive zoites, and demonstrates the presence at the malaria merozoite surface of a rhomboid-like protease.

The authors report on sexual orientation disclosure issues considered by lesbian, gay, and bisexual students and physicians during their medical school and residency selection process.