Prehospital treatment of acute asthma in a rural state.

BACKGROUND: Acute asthma exacerbations can be life threatening and are recognizable to emergency medical service (EMS) personnel; however, the therapies and medications which these emergency service personnel can use to treat exacerbations are limited. Several studies have demonstrated the effective use of beta2-agonist therapy in the treatment of patients complaining of wheezing or dyspnea, yet few EMS personnel can administer them. OBJECTIVE: The purpose of this study was to determine what therapeutic interventions emergency personnel around the state of New Mexico could use when responding to a call for a severe asthma exacerbation. METHODS: Questionnaires were distributed over a period of three years, 1992-1994, to all Emergency Service Agencies in New Mexico. RESULTS: Eighty percent of the emergency medical personnel administer oxygen to patients experiencing acute asthma exacerbations. Seventeen percent of EMS personnel administer epinephrine, 4% administer steroids, and only 23% administer beta2 agonists. Only in more populated areas were EMS personnel allowed to administer beta2 agonists, and those personnel had to have at least intermediate-level training. Most emergency response teams in the state consisted of EMT Basics and provided only basic life support services. In rural New Mexico, transport to a hospital can often take over one hour, which left EMS crews feeling helpless. CONCLUSIONS: We conclude that due to the rural nature of New Mexico, EMS personnel should be trained in the use of beta2 agonists and allowed to administer them to patients with acute asthma exacerbations. In addition, standard protocols for the pre-hospital management of acute asthma exacerbations should be instituted.

Common problems in the diagnosis of immunodeficiency in children.

Primary immunodeficiency (ID) has an incidence of 1 in 10,000 and may have significant morbidity and mortality if not diagnosed and treated early. Children with signs and symptoms suggestive of immunodeficiency are often seen first by their paediatrician or family medical practitioner. For these reasons, it is essential that primary care physicians both of children and adults should be able to recognize the signs and symptoms of immunodeficiency and be knowledgeable about the screening procedures useful in the diagnosis of these diseases. However, this process is often complicated by the diverse presentations of immunodeficiency and the lack of specificity and relative inaccessibility of screening tests. The purpose of this paper is to address the major problems in diagnosis of immunodeficiency, including: 1) Which patients to seriously consider for diagnosis? 2) How to begin the work-up for primary immunodeficiency? 3) Which procedures are useful in the diagnosis of the various forms of immunodeficiency? and 4) What is the relative importance of immunoglobulin (IgG) subclasses?

A comparative analysis of cytoplasmic mu (C mu) expression in acute lymphoblastic leukemia by molecular and immunologic techniques. Identification of leukemia cases expressing C mu mRNA transcripts in the absence of detectable C mu proteins.

Among acute lymphoblastic leukemias derived from the B-cell lineage, the subset of cases expressing cytoplasmic mu heavy chain proteins (C mu) in the absence of surface immunoglobulin has been designated pre-B-cell acute lymphoblastic leukemia. This group, traditionally identified using immunologic smear techniques, has been associated with a poor prognosis in some series. In a comparative study, 25 cases of B-lineage acute lymphoblastic leukemia were analyzed for C mu expression using molecular and immunologic techniques. RNA derived from cryopreserved blast cells was hybridized in both Northern and slot-blot analyses using a probe (pBZ311) containing four exons of the human immunoglobulin heavy chain mu constant region gene. Expression of C mu proteins was assessed simultaneously by slide immunofluorescence and flow cytometric techniques in all samples. These studies were correlated with immunoglobulin heavy and light chain gene rearrangements, cell-surface immunophenotype, cytogenetics, and other clinicopathologic features. C mu mRNA transcripts were detected in 14 of 25 cases, whereas C mu proteins were detected in only 9 of these cases using flow cytometric techniques. Only four of these nine cases were positive by slide immunofluorescence techniques. These studies imply that molecular and flow cytometric techniques may be a more sensitive means to assess C mu expression. The identification of five cases that expressed C mu mRNA transcripts in the absence of detectable C mu proteins also suggests that molecular techniques may be valuable in identifying a unique subgroup of pre-B-cell acute lymphoblastic leukemia cases that contain C mu mRNA transcripts, but lack C mu proteins.

Antisera to the secretory component recognize the murine Fc receptor for IgA.

Studies were undertaken to determine a possible structural relationship between the secretory component (SC) and the receptor for IgA (Fc alpha R). An IgA-mediated rosetting technique was used to assess the presence of Fc alpha R+ cells in various lymphoid tissues from normal BALB/c mice and mice bearing an IgA plasmacytoma (MOPC 315). Tissues from the MOPC 315-bearing BALB/c mice were found to have a significantly higher percentage of Fc alpha R+ cells; thus, nonadherent spleen cells from MOPC 315-bearing mice were used as a source of Fc alpha R+ cells in these studies. The cells were preincubated with anti-SC and then assayed for the ability of IgA to bind to the Fc alpha R. Antisera to SC from various species inhibited the formation of IgA-mediated rosettes, although preincubation of the Fc alpha R+ cells with antisera directed against other cell surface molecules (e.g., Thy1.2, Lyt1, Lyt2, Fc gamma R, MHC class I and II) or preimmune sera had no significant effect on IgA-mediated rosette formation. Preabsorption of the anti-SC with secretory IgA or with free SC removed the inhibitory effect; preabsorption with myeloma IgA had no effect. These data suggest that SC and Fc alpha R are related serologically and may be structurally related, possible in the IgA-binding region.

Hematogones: a multiparameter analysis of bone marrow precursor cells.

Morphologically distinct lymphoid cells with homogeneous, condensed chromatin and scant cytoplasm can be observed in large numbers in the bone marrow of children with a variety of hematologic and nonhematologic disorders. In some patients, these cells may account for greater than 50% of the bone marrow cells, creating a picture that can be confused with acute lymphoblastic leukemia (ALL) or metastatic tumor. Although originally called hematogones (HGs), a variety of other names have been proposed for these unique cells. The clinical significance of expanded HGs has not been resolved, and the biologic features of these cells are incompletely described. In this study, we correlate the clinical, morphologic, cytochemical, flow cytometric, molecular, and cytogenetic properties of bone marrow samples from 12 children with substantial numbers of HGs (range 8% to 55% of bone marrow cells). Diagnoses in these patients included anemia, four; neutropenia, one; anemia and neutropenia, one; idiopathic thrombocytopenic purpura, two; retinoblastoma, two; Ewing's sarcoma, one; and germ cell tumor, one. Flow cytometric analyses of bone marrow cells demonstrated a spectrum extending from early B-cell precursors (CD10+, CD19+, TdT+, HLA-Dr+) to mature surface immunoglobulin-bearing B cells in these patients, corroborating our morphologic impression of HGs, intermediate forms, and mature lymphocytes. DNA content was normal, and no clonal abnormality was identified by either cytogenetic or immunoglobulin and T-cell receptor (TCR) gene rearrangement studies. Follow-up ranged from 3 months to 3 years. None of the patients has developed acute leukemia or bone marrow involvement by solid tumor. The possible role of HGs in immune recovery and hematopoiesis is presented.

Flow cytometric analysis of lymphoma and lymphoma-like disorders.

The use of flow cytometry (FC) represents the most recent advance in the phenotypic analysis of lymphocyte subsets, and has emerged as a valuable adjunct in the diagnosis of malignant non-Hodgkin's lymphoma (NHL). In a review of over 200 cases of nodal and extranodal suspected lymphomas studied in the Immunophenotyping Laboratory at the University of New Mexico, the diagnostic utility of FC was assessed. Among cases of NHL, FC was able to confirm a morphologic diagnosis of lymphoma and determine B or T cell lineage in greater than 85% of the samples submitted. Difficulty in lineage determination in the remaining cases of morphologic NHL was multifactorial. Among cases of reactive lymph nodes and Hodgkin's disease, FC showed no characteristic patterns, although several cases exhibited phenotypic profiles suggestive of B or T cell clonality. When combined with routine morphologic review and accompanied by other specialized diagnostic techniques when necessary, the use of FC represents a precise and reproducible method for rapidly and easily studying lymphoproliferative disorders in solid tissue.

Organization and operation of a flow cytometric immunophenotyping laboratory.

Technical advances in the field of flow cytometry have made it feasible for many academic and private hospital laboratories to purchase relatively inexpensive "user friendly" flow cytometers that do not require dedicated flow cytometer operators, special rooms, or a significant amount of laboratory space. Because the financial and physical constraints in operating a flow cytometer have been substantially reduced, many pathologists may now be considering such a purchase. By chronicling the clinical activities of a single flow cytometric immunophenotyping laboratory, this report will answer a variety of questions that may be asked by pathologists regarding both the utility of flow cytometers in clinical diagnosis and the mechanics of operating an immunophenotyping laboratory. The types of tissues that can be evaluated by flow cytometry will be detailed, and we will summarize the number and type of flow cytometric clinical studies performed in our laboratory since its development in 1983. Practical aspects of laboratory operation including technical staff requirements, specimen handling and processing procedures, monoclonal antibody selection, and quality control procedures will be presented. In addition, a comprehensive review of flow cytometric immunophenotyping studies as applied to the diagnosis of leukemias, lymphomas, and immunodeficiency disorders will be presented along with case examples that illustrate our approach to the interpretation of immunophenotyping results.

Inhibition of natural killer cell activity by IgA.

The in vitro effect of IgA on natural killer (NK) activities of human peripheral blood mononuclear cells was investigated. Purified myeloma polymeric IgA2 (pIgA2) and secretory IgA (S-IgA) from human colostrum inhibited NK activity, while myeloma polymeric IgA1 (pIgA1), monomeric IgA1 (mIgA1), IgG, and IgM were ineffective. Inhibition was proportional to the concentration of pIgA2 (0.125-1 mg/ml) and was observed after as little as 1 hr of incubation at various effector to K562 target cell ratios. pIgA2 and S-IgA also inhibited NK activity of NK cell-enriched lymphoid cells and gamma-interferon-treated effector cells, but did not interfere with effector-target cell binding. The inhibitory effect was slightly diminished after 24 hr culture in pIgA2-free medium. Inhibition of cytotoxicity was not due to direct toxicity on lymphoid cells by IgA because PBL treated with pokeweed mitogen in the presence of pIgA2 or S-IgA differentiated into immunoglobulin-producing cells. Viability after 24 hr of preculture with pIgA2 and S-IgA was comparable to that of untreated control cells. Morphological examination of effector cells cultured with pIgA2 or S-IgA showed a decrease in the number of granules, and the formation of cytoplasmic vacuoles. These morphological changes appeared to coincide with the depressed cytotoxicity of NK cells. The results demonstrate that purified pIgA2 and S-IgA have significant immunomodulatory effects on human NK activity.

Circulating immune complexes and immunoglobulin A rheumatoid factor in patients with mesangial immunoglobulin A nephropathies.

Circulating immune complexes (CIC) containing IgA and C3 were elevated in 48% of IgA nephropathy patients; IgA1 was the predominant subclass. IgA1-IgG CIC were detected in 44%, IgA2-IgG CIC in 7%, and IgM-IgA1 CIC in 16% of the patients. No IgM-IgA2 CIC were detectable. Sucrose gradient ultracentrifugation indicated that IgG-IgA1 CIC were predominantly of intermediate (13-19S) size whereas IgA1-C3 CIC sedimented from 11S to 19S. At acid pH, isolated CIC revealed the presence of substantial amounts of 7S IgA. One third of the patients had elevated serum IgA rheumatoid factor (RF) of both polymeric and monomeric forms despite normal levels of IgM-RF; 87% of patients with elevated IgA-RF had IgA1-IgG CIC. These results indicate that the IgA1 component of CIC in patients with IgA nephropathy is not necessarily of mucosal origin and suggest that a portion of these CIC consists of IgA RF immunologically complexed with autologous IgG.

Regulation of IgA expression by isotype-specific T cells and soluble binding factors.

The data presented here suggest a model for isotype-specific regulation of IgA synthesis by Fc alpha R+ T cells (Figure 1). Immature mIgM+ +/- mIgD+ B cells are induced by T switch cells to express cell surface IgA (a phenotypic switch). If the T switch cell induces mIgA expression via a long primary RNA transcript from an unrearranged C alpha allele, the hypothetical intermediate switch B cell results (step 1); this may be the mechanism of heavy chain expression in memory B cells that express low levels of Ig. Alternatively, T switch cells may induce a DNA rearrangement in the CH locus of the B cell (a genotypic switch), which results in a deletion of all CH loci except C alpha (step 2). TH inducer cells promote maturation of mIgA+ B cells to IgA-secreting plasma cells. This may involve a DNA switch rearrangement (step 3) or the maturation of previously switched cells (step 4), and appears to be mediated via an IgABF with enhancing activity. Not shown in this figure, but inherent in this model, is a suppressive regulatory arm that may be mediated via IgABF with suppressive activity released from Fc alpha R+ suppressor T cells. Due to the presence of Fc alpha R on a variety of cell types, IgABF may suppress synthesis of IgA by acting not only on mIgA+ B cells but also on regulatory cells (T cells, B cells, and macrophages) bearing IgA bound to Fc alpha R. If the IgA system is analogous with the IgE system, mIgA-bearing B cells may be the direct target of IgABF. Binding of Ig to FcR has been shown to (a) increase the number of Fc receptors per cell, (b) enhance the number of cells expressing Fc receptors, (c) induce the release of IgBF that either suppress or enhance Ig secretion, and (d) effectively convert surface Ig- cells into surface Ig+ cells that are therefore receptive to IgBF. Thus, FcR+ cells may interact with IgBF and Ig via a regulatory network to stimulate or inhibit the immune response in an isotype-specific manner. Cell surface molecules (mIg, FcR) may serve as sensors that allow the cell to detect and respond to fluctuations in the levels of immune mediators that serve to modulate Ig synthesis and secretion. The relationship between IgBF and FcR is not known, nor is it known whether Fc receptors expressed by different cell types are encoded by the same gene and are controlled similarly.(ABSTRACT TRUNCATED AT 400 WORDS)

IgA rheumatoid factor synthesis by dissociated synovial cells. Characterization and relationship to IgM rheumatoid factor synthesis.

We examined patterns of IgA rheumatoid factor (RF) and IgM-RF synthesis by dissociated synovial cells obtained from 27 patients with seropositive rheumatoid arthritis. Synthesis of IgA-RF was observed in 19 of 34 synovial cell preparations from these patients and constituted a mean of 16% of the total IgA produced. IgA-RF expression correlated only weakly with IgM-RF production (r = 0.385) and could be dissociated from production of IgA-RF (and IgM-RF) exhibited by simultaneously obtained peripheral blood plasma cells. While wide variations were observed in the ratio of IgA-RF:IgM-RF produced by synovial B cells in the patient sample studied, remarkable consistency in the relationship of IgA-RF to IgM-RF synthesis was observed over time in different joints of the same patient. IgA-RF synthesized by dissociated synovial cells was predominantly of the IgA1 subclass and existed in both monomeric and polymeric forms. Our results are compatible with the view that local production of IgA-RF and IgM-RF are regulated independently of each other.

Natural killer cells in human colostrum.

The presence of natural killer cells in human colostrum was disclosed with the use of a fluorochrome-labeled monoclonal antibody HNK-1 (Leu-7) that recognizes cells with natural killer and killer activity. Approximately 0.5% of total colostral cells were stained with this reagent. These cells were separated by the fluorescence-activated cell sorter and examined for their morphology by electron microscopy and for their cytotoxic activity against 51Cr-labeled K562 target cells. Two morphological types of natural killer cells were observed in colostrum: the first was represented by large cells with numerous vacuoles but without dense cytoplasmic granules; the second type, which occurred with lower frequency, resembled the large granular lymphocytes associated with natural killer activity in peripheral blood. The HNK-1-positive cells from colostrum displayed low cytotoxic activity against K562 target cells. Incubation of HNK-1-positive cells from peripheral blood with cell-free colostrum resulted in a dose-dependent inhibition of the cytotoxic activity. The functional changes were accompanied by morphological alterations which included degranulation and the formation of numerous vacuoles. The variances in the cytotoxic activity of peripheral blood HNK-1-positive cells suspended in different dilutions of colostrum suggest that this fluid contains humoral factors which modify morphology and function depending on their concentrations.

Human colostral cells. II. Response to mitogens.

The ability of colostral lymphocytes to respond to pokeweed mitogen, phytohemagglutinin, or Epstein-Barr virus was examined. None of these mitogens induced colostral cells to differentiate into immunoglobulin-containing cells, either in the absence or in the presence of mitomycin C-treated mononuclear cells or T-cell-enriched populations from peripheral blood. Cocultivation of mononuclear cells from the peripheral blood of normal adults with mitomycin C-treated colostral cells resulted in a marked suppression of the generation of immunoglobulin-containing cells in response to pokeweed mitogen. The inhibitory effect was seen in peripheral blood mononuclear cell:colostral cell ratios of 1:1, 5:1, and 10:1. However, colostral cells had little effect on the ability of peripheral blood lymphocytes to proliferate in response to phytohemagglutinin or to allogeneic stimulation.

Immunohistochemical distribution of immunoglobulins, lactoferrin, and lysozyme in human minor salivary glands.

The immunofluorescence technique was used to examine the distribution of immunoglobulin A and its subclasses, secretory component (SC), J chain, lactoferrin and lysozyme in labial and lingual (von Ebner's) glands. IgA-containing plasma cells were found in the connective tissue around intercalated or intralobular ducts and a few were noted around acini of both glands. IgA was detected in the apical cytoplasm of intercalated and intralobular duct cells and in acini of von Ebner's glands and in demilunes of labial glands. Most IgA-containing cells also stained for J chain. The ratio of IgA1:IgA2-containing cells was approximately equal in von Ebner's and labial glands. Cytoplasmic and surface membrane-related staining for SC was detected in epithelial cells of the intercalated and intralobular ducts in both glands, in the serous acini of von Ebner's gland, and in the demilunes of labial glands. Lactoferrin was found in serous acini, demilunes, intercalated and intralobular ducts. Lysozyme was found in acinar and intercalated ducts, but was rarely seen in intralobular ducts. These results disclose the presence of cells (plasma cells and epithelial cells) and their products (IgA and secretory component) that indicate the local production of secretory IgA in minor salivary glands.

Localization of IgA and IgM in human colostral elements using immunoelectron microscopy.

In addition to the free form, IgA is associated with cellular and noncellular elements present in human colostrum. To resolve the existing controversy as to the cell type(s) containing IgA, we used immunoelectron microscopy with horseradish peroxidase-labeled F(ab')2 or Fab' fragments of anti-IgA or anti-IgM to determine the distribution of these immunoglobulins in colostral elements. IgA and IgM were localized in phagocytic vacuoles of polymorphonuclear leukocytes and macrophages in the vicinity of the cell membrane. In neutrophilic leukocytes, both immunoglobulins were occasionally found in phagocytic vacuoles distributed throughout the cytoplasm. Although the in vitro phagocytic activity of colostral cells was low, they retained the ability to ingest colloidal gold particles which were subsequently localized in phagocytic vacuoles that also contained IgA or IgM. IgA and IgM were not detected in lymphocytes, and plasma cells were not found in human colostrum. Numerous noncellular colostral globules of various shapes and sizes also contained IgA and IgM. These observations indicate that IgA and IgM were acquired by phagocytic cells and noncellular globules and were not actively synthesized by lymphoid cells present in human colostrum.