Secretion of immunoglobulins and plasma proteins from the jejunal mucosa. Transport rate and origin of polymeric immunoglobulin A.

Parameters of secretion of IgA and several other plasma proteins from the jejunal mucosa were investigated in 11 individuals who had a normal distribution of Ig-containing cells in the lamina propria and in one patient who was totally deficient in jejunal IgA and IgM plasmacytes. Jejunal samples were collected during segmental gut perfusion. The following results were obtained: (a) The secretion of polymeric IgA (p-IgA, mean equals 217 micrograms/40 cm per min) exceeded those of albumin (132 micrograms), IgG (35 micrograms), and monomeric IgA (m-IgA, 15 micrograms, or 6.4% of total IgA). About 35% of IgA was IgA2 in the jejunal secretion, compared with approximately 23% in serum. This closely corresponds to the 35 and 24% of IgA2 plasmocytes in jejunal mucosa and peripheral lymph nodes, respectively. (b) For each protein, a relative coefficient of excretion (RCE) was calculated (jejunum to serum concentration ratio expressed relative to that of albumin). RCEs of 1.41 for orosomucoid, 1.0 for albumin, 0.83 for IgG, and 0.74 for IgE and, in the deficient patient, of 0.64 for m-IgA and 0.016 for IgM were obtained. This was inversely related to the molecular weight of these proteins and indicated their predominantly passive transport into the jejunum. However, in normal individuals, the RCE of transferrin (approximately 1.11 greater than 1, P greater than 0.05), alpha 2-macro globulin (approximately 0.77), m-IgA (approximately 1.98), and p-IgA (approximately 218) exceeded the value expected from simple seepage from plasma, thus pointing to an additional role of either local gut synthesis and/or active transepithelial transport. (c) Approximately 98% of p-IgA, approximately 99% of IgM, and approximately 68% of m-IgA in jejunal secretions were derived from local production in the gut wall, as determined by 125I-p-IgA specific activities and/or by comparison between the RCE values of the deficient patient to the values of controls. Therefore, the jejunal production of p-IgA (approximately 312 mg/d per 40 cm vs. approximately 54 mg/d from bile) contributes the majority of upper intestinal IgA in humans. The active transport of plasma p-IgA across the intestinal mucosa (approximately 0.08 mg/40 cm per kg per d) contributes less than 2% of the total amount of p-IgA (4.5 mg/kg per d) that is cleared daily from plasma.     

Changes in size, subclass, and metabolic properties of serum immunoglobulin A in liver diseases and in other diseases with high serum immunoglobulin A

We have studied the relative contributions of monomeric (m-) and polymeric IgA (p-IgA) and of IgA1 and IgA2 to total serum IgA in healthy adults and patients with liver disease (LD) or with other diseases and high serum IgA. Serum concentration of total secretory component (SC) was also determined. In addition, fractional catabolic rates (FCR) and synthetic rates for both m- and p-IgA were measured in nine controls and nine cirrhotics. Our results support four main conclusions: (a) In healthy adults, intravascular p-IgA contributes to only 4-22% (mean 12%) of serum IgA, because its FCR and synthetic rate are approximately two times higher and four times smaller, respectively, than those of intravascular m-IgA. (b) in LD, biliary obstruction does not result in a significant increase in serum p-IgA unlike in rats and rabbits, indicating that in humans the SC-dependent biliary transport of p-IgA plays a much less significant role in selective removal of p-IgA from plasma than in rats and rabbits. (c) In contrast to biliary obstruction, parenchymal LD results in a significant and preferential increase in serum p-IgA, which in cirrhotics correlates with a selective reduction of the p-IgA-FCR. This supports a role for the human liver in selective removal of p-IgA from plasma, but another mechanism than the SC-dependent biliary transport should be considered. (d) Total SC, p-IgA, and IgA2 in serum are unlinked parameters, not necessarily reflecting mucosal events. A marked increase in serum SC occurs almost selectively in LD. Although a shift to IgA2 is suggested in Crohn's disease and alcoholic cirrhosis, a shift to IgA1 frequently associated to a shift to p-IgA occurs in chronic active LD, primary Sicca, and connective tissue diseases.     

Role of serum IgA. Hepatobiliary transport of circulating antigen

The IgA mediated hepatobiliary excretion of antigen from the circulation was studied using a radiolabeled haptenated protein (dinitrophenyl-human serum albumin) injected intravenously in mice together with monoclonal anti-dinitrophenyl antibodies of different immunoglobulin classes. Antibodies were obtained from ascitic fluids of mice bearing the MOPC315 myeloma (IgA), or immune spleen cell hybridomas (IgG and IgM). IgA antibody brought about the transport of large amounts of antigen from the circulation to the bile during 1-3h. Analysis of bile by gel filtration showed that a large part of the transported antigen remained intact and complexed with IgA. Neither IgA of different specificity nor anti-dinitrophenyl IgM medicated biliary transport of antigen. With anti-dinitrophenyl IgG, only small amounts of low molecular weight fragments of labeled antigen were found in he bile. Preformed immune complex of radiolabeled antigen and IgA antibody were rapidly transported from the circulation to the bile, resulting in threefold-higher levels of radioactivity in bile than in serum. It is proposed that an important function of serum IgA is to mediate the hepatobiliary excretion of corresponding circulating antigens.     

Absence of epithelial immunoglobulin A transport, with increased mucosal leakiness, in polymeric immunoglobulin receptor/secretory component-deficient mice.

Mucosal surfaces are protected specifically by secretory immunoglobulin A (SIgA) and SIgM generated through external translocation of locally produced dimeric IgA and pentameric IgM. Their active transport is mediated by the epithelial polymeric Ig receptor (pIgR), also called the transmembrane secretory component. Paracellular passive external transfer of systemic and locally produced antibodies also provides mucosal protection, making the biological importance of secretory immunity difficult to assess. Here we report complete lack of active external IgA and IgM translocation in pIgR knockout mice, indicating no redundancy in epithelial transport mechanisms. The knockout mice were of normal size and fertility but had increased serum IgG levels, including antibodies to Escherichia coli, suggesting undue triggering of systemic immunity. Deterioration of their epithelial barrier function in the absence of SIgA (and SIgM) was further attested to by elevated levels of albumin in their saliva and feces, reflecting leakage of serum proteins. Thus, SIgA did not appear to be essential for health under the antigen exposure conditions of these experimental animals. Nevertheless, our results showed that SIgA contributes to maintenance of mucosal homeostasis. Production of SIgA might therefore be a variable in the initiation of human immunopathology such as inflammatory bowel disease or gluten-sensitive enteropathy.     

Rapid active transport of immunoglobulin A from blood to bile

Immunoglobulins were isolated from the serum or ascitic fluid of Lou/Wsl rats bearing plasmacytomas and labeled with 125I. When labeled IgA was injected i.v. it disappeared from the blood serum much more rapidly than IgG2 so that after 3 h less than 10% remained. This rapid disappearance of the injected IgA was not seen in rats with ligated bile ducts. In rats with cannulated bile ducts, the labeled IgA appeared rapidly in the bile so that 25% of the injected dose was recovered in 3 h; at the peak of this biliary excretion the specific radioactivity of the bile (cpm/milligram protein) was about 200 times greater than that of the blood serum. Thus much of the IgA which finds its way into the blood is rapidly and actively transported across the liver so that it enters the gut lumen via the biliary tract.     

Secretory and serum immunoglobulin class-specific antibodies to mumps virus after a natural mumps infection

Immune responses in serum and saliva were studied in 50 individuals following a natural exposure to mumps virus, using ELISA for detection of mumps-specific IgG, IgM and IgA antibodies.Laboratory diagnosis of acute mumps using a single saliva sample offers a convenient alternative to collection of blood: high levels of mumps IgM were found in all serum and saliva samples taken from patients with acute mumps. Furthermore, in such patients, levels of mumps IgA were considerably higher in saliva compared with serum, with the exception of three patients. Conversely, mumps-specific IgM and IgA were present in neither serum nor saliva samples of patients with a remote mumps infection.Saliva samples are not suitable for immune status (IgG) determinations because high levels of mumps IgG antibodies were present only in serum samples of patients with either a recently acquired (≥ 15 days after onset) or a remote mumps infection.Serum and saliva mumps-specific IgA antibodies appeared to be a reliable acute phase marker as, like IgM antibodies, they were present in all tested serum/saliva samples taken shortly after the onset of the disease (1–5 days), were detected for a limited period of time (up to 3 months), and were absent from serum and saliva samples of patients with a remote infection.     

Familial hypercatabolic hypoproteinemia. A disorder of endogenous catabolism of albumin and immunoglobulin.

The metabolism of albumin and IgG was investigated in two siblings, products of a first-cousin marriage, a female aged 34 yr and a male aged 17, who had a marked reduction in their respective serum concentrations of IgG (1.3 and 3.1 mg/ml) and albumin (19 and 21 mg/ml). The metabolism of radioiodinated IgG and albumin was studied in the two patients. The total circulating and body pools of IgG were less than 28% of normal. The IgG synthetic rates were within the normal range. However, the IgG survival was short, with their respective fractional catabolic rates increased fivefold to 31% and 36% of the intravenous pool per day (normal, 6.7 +/- 2%/d). Furthermore, the patients had reduced total body pools, normal synthetic rates, and increased fractional catabolic rates for albumin. There was no proteinuria or abnormality of renal or liver function. In addition, the patients did not have circulating antibodies directed toward IgG, IgA, or albumin. Furthermore, both patients had normal fecal 51Cr-labeled albumin tests, thus excluding excessive gastrointestinal protein loss. We propose that these siblings have a previously unrecognized familial disorder characterized by reduced serum concentrations of IgG and albumin caused by a defect in endogenous catabolism, leading to a short survival of these proteins that is associated in this family with chemical diabetes and a skeletal deformity.     

Optimization of gel radial diffusion method for serum immunoglobulin analysis

Serum IgA, IgM, and IgG were measured by radial immunodiffusion in gel; immunoglobulin concentrations correlated with the diameter of their diffusion. A theoretically-based equation was derived; use of this equation will help estimate serum Ig content without plotting a calibration curve by the square diameter of the immunodiffusion ring of undiluted reference serum in a wide range of concentrations (0.3-3 mg/ml for IgA and IgM and 2-18 mg/ml for IgG). This modification of measuring serum immunoglobulins by radial immunodiffusion in gel is as accurate as other methods, but is reagent- and time-saving.     

Classification of renal proteinuria: a simple algorithm.

Total protein, albumin, alpha1-microglobulin, and immunoglobulin G (IgG) were analyzed in 1,622 urine samples without Bence-Jones proteinuria or gross hematuria. There was correlation with the histological picture obtained on renal biopsy in 61 patients. We established 24-h reference intervals for alpha1-microglobulin and IgG on 659 urine samples with total protein and albumin excretion rates below 100 mg/24 h and 30 mg/24 h, respectively, and creatinine clearance above 80 ml/min. The central 95% reference interval was found to be between 4 and 17 mg/24 h for alpha1-microglobulin and between 3 and 8.5 mg/24 h for IgG. In 80 urine samples with albumin excretion rate above 30 mg/24 h and alpha1-microglobulin and IgG within their reference intervals, we analyzed the 95% central interval of the distribution of the IgG/albumin ratios, and it was found to be within 0.01 and 0.20 (0.90 confidence interval: 0.17-0.24). Proteinuria was considered to be of the selective glomerular type if the albumin excretion rate was abnormal and the IgG/albumin ratio was under 0.20, even when the IgG excretion was within a pathological range. For the classification of proteinuria as predominantly tubular, we estimated the alpha1-microglobulin/albumin ratio in 173 urine samples with normal excretion rates of albumin and IgG and pathological excretion of alpha1-microglobulin. The discriminating value of 0.91 (0.90 confidence interval: 0.78-1.08) was accepted in order to define proteinuria of a tubular origin in the presence of a pathological albumin excretion rate. The association between albumin and IgG excretion rates and tubular reabsorption of the alpha1-microglobulin normally filtered by the glomerulus was studied in 33 urine samples from patients with no histologically significant tubulo-interstitial or vascular disease and a serum creatinine concentration below 141 pmol/l. The optimal curve-fitting function between albumin plus IgG and alpha1-microglobulin excretion rates was of the quadratic type (r = 0.927). Mixed proteinuria was considered when both, albumin and alpha1-microglobulin excretion rates were pathological and could not be included in the previously described groups.     

gamma/delta T cell-deficient mice have impaired mucosal immunoglobulin A responses

Mucosal tissues of mice are enriched in T cells that express the gamma/delta T cell receptor. Since the function of these cells remains unclear, we have compared mucosal immune responses in gamma/delta T cell receptor-deficient (TCRdelta-/-) mice versus control mice of the same genetic background. The frequency of intestinal immunoglobulin (Ig) A plasma cells as well as IgA levels in serum, bile, saliva, and fecal samples were markedly reduced in TCRdelta-/- mice. The TCRdelta-/- mice produced much lower levels of IgA antibodies when immunized orally with a vaccine of tetanus toxoid plus cholera toxin as adjuvant. Conversely, the antigen-specific IgM and IgG antibody responses were comparable to orally immunized control mice. Direct assessment of the cells forming antibodies against the tetanus toxoid and cholera toxin antigens indicated that significantly lower numbers of IgA antibody- producing cells were present in the intestinal lamina propria and Peyer's patches of TCRdelta-/- mice compared with the orally immunized control mice. The selective reduction of IgA responses to ingested antigens in the absence of gamma/delta T cells suggests a specialized role for gamma/delta cells in mucosal immunity.     

Glycated proteins in serum: effect of their relative proportions on their alkaline reducing activity in the fructosamine test

The fructosamine test is considered clinically useful for assessing short-term integrated control of blood glucose, but there are few published data to support this hypothesis. We fractionated glycated and nonglycated proteins by affinity chromatography on phenylboronate columns and, with specific immunochemical methods, determined in the eluted fractions the following proteins, selected according to their biological half-lives and relative concentrations in serum: albumin, IgA, IgG, IgM, apolipoprotein B, haptoglobin, transferrin, alpha 1-antitrypsin, and alpha 2-macroglobulin. We found the following correlations between fructosamine (mmol/L) and, respectively, glycated albumin, IgG, and (albumin + IgG) (each in grams per liter): r = 0.901, 0.702, 0.878. IgM had the highest percentage of glycated molecules (range 11.1-37.5%, mean 22.4%), haptoglobin and alpha 1-antitrypsin the least. This result was almost independent of the proteins' molecular masses and fractional catabolic rate. Albumin evidently contributes most to results of the fructosamine test, confirming conclusions obtained in different ways by others.     

Immunoglobulins in the hyperimmunoglobulin E and recurrent infection (Job''s) syndrome. Deficiency of anti-Staphylococcus aureus immunoglobulin A.

Patients with the hyperimmunoglobulin E and recurrent infection syndrome (HIE) characteristically have frequent skin and respiratory infections caused by Staphylococcus aureus. We have developed a set of enzyme-linked immunosorbent assays that use whole S. aureus (Wood's strain) immobilized on 0.22-micrometers filters and highly specific, affinity-purified enzyme conjugates of goat anti-human IgE, anti-human IgD, anti-human IgG, anti-human IgA, and anti-human IgM. These reagents were used to determine S. aureus-specific immunoglobulin (Ig) levels. As previously published, 10 patients with HIE had markedly higher levels of anti-S. aureus IgE than did 5 patients with eczema and recurrent superficial S. aureus infections (P less than 0.001). The HIE patients were also found to have a deficit of anti-S. aureus serum IgA as compared with 12 normal subjects, 12 patients with chronic granulomatous disease, 5 patients with chronic eczema and recurrent superficial S. aureus infections, and 3 patients with the Chediak-Higashi syndrome (P less than 0.01 for each comparison). In addition the HIE patients had an excess of anti-S. aureus IgM as compared with normal subjects (P less than 0.01). An expected excess of anti-S. aureus IgG was absent. These abnormalities cannot be explained by variations of total serum Ig levels or by a general inability to produce antigen-specific IgA because levels of naturally occurring IgA antibody against Escherichia coli lipopolysaccharide and the antigens of the pneumococcal vaccine are normal. Parotid saliva from patients with HIE contained less salivary IgA per milligram of protein (P less than 0.01) and less salivary anti-S. aureus IgA per milligram of protein (P less than 0.05) than did normal controls. The incidence of infection at mucosal surfaces and adjacent lymph nodes correlated inversely with serum anti-S. aureus IgA (r = -0.647, P = 0.034), serum anti-S. aureus IgE (r = -0.731, P = 0.016), total serum IgE (r = -0.714, P = 0.020), and total serum IgD (r = -0.597, P = 0.049). These findings are evidence of a previously undescribed immunoregulatory defect in patients with HIE, which may contribute to the increased susceptibility to infection in this syndrome.     

Trimethoprim and sulfadiazine penetration into bile and gallbladder in acute cholecystitis

The concentrations of trimethoprim (TMP) and sulfadiazine (SDZ) in serum, bile and gallbladder wall of 9 patients with acute cholecystitis were measured after b.i.d. treatment with 160 mg of TMP + 500 mg of SDZ. The samples were collected 2-4 h after the last dose. Mean TMP concentrations were 1.71 +/- (SE) 0.51 micrograms/ml, 4.53 +/- 5.26 micrograms/ml and 2.31 +/- micrograms/g in serum, bile and gallbladder, respectively. Mean SDZ concentrations were 22.2 +/- 14.9 micrograms/ml in serum, 9.37 +/- 8.99 micrograms/ml in bile and 16.1 +/- 10.1 micrograms/g in gallbladder. The average ratios of bile-serum and gallbladder-serum concentrations were 2.64 and 1.35 for TMP and 0.42 and 0.73 for SDZ. There was a significant correlation between serum and gallbladder concentrations of both TMP and SDZ. No correlation existed between serum and bile levels.     

Quantitative assessment of urinary protein and enzyme excretion--a diagnostic programme for the detection of renal involvement in type I diabetes mellitus.

In an effort to establish a reliable programme for the clinical monitoring of renal involvement in patients with type-I diabetes mellitus, we quantified the urinary excretion of immunoglobulin G (IgG), transferrin (Tf), albumin (Alb), alpha 1-microglobulin (alpha 1MG), N-acetyl-beta-D-glucosaminidase (NAG), and total protein in 130 dipstick negative children and young adults with type-I diabetes. Eighty-five sex- and age-matched healthy persons served as a control group for the definition of the upper reference limits (95th centiles; micrograms min-1 1.73 m2): transferrin 1.4; albumin 16.6; total protein 27.1; NAG: 2.0 mU min-1 1.73 m2. Sex-related differences were detected for IgG (men: 3.8; women: 1.7) and alpha 1 MG (men: 6.0; women: 4.0 micrograms min-1 1.73 m2). The urinary excretion of IgG, Tf, alpha 1MG, NAG, and total protein was significantly higher in subjects with diabetes when compared to healthy controls (p < 0.01). Furthermore, 20 patients (15%) showed an elevated excretion of tubular markers (alpha 1MG and NAG), and 3 patients (2%) of at least two glomerular markers (Alb and/or Tf and/or IgG). Additionally, 18 individuals (14%) presented a mixed excretion pattern of both tubular and glomerular markers. These data suggest that the quantitation of both glomerular and tubular proteinuria provides a sensitive and cost-effective instrument for the non-invasive screening for renal involvement in patients with diabetes mellitus.     

Light-chain ratios of immunoglobulins G, A, and M determined by enzyme immunoassay

We describe an enzyme-linked immunosorbent assay for determination of light-chain ratios for IgG, IgA, and IgM in serum. A commercial serum with known overall kappa and lambda concentrations was used as standard. To capture the respective immunoglobulins, we used antibodies to gamma, lambda and mu chains coated onto microtiter plates. Peroxidase-conjugated anti-kappa and anti-lambda chain antisera were reacted with light chains on the captured immunoglobulins, and the amount of enzyme bound was monitored with o-phenylenediamine and urea-hydrogen peroxide as substrates. Calculation of absorbance ratios allowed determination of kappa and lambda chain concentrations of individual immunoglobulins in the standard and samples. Within-run and between-run CVs (n = 25) ranged from 5.9% to 13.0% for "high," "normal," and "low" kappa/lambda ratios for IgG, IgA, and IgM. The thoroughness of light-chain detection, expressed as, e.g., (IgA kappa + IgA lambda)/(total IgA), for 150 sera was 91-110%. The detection limit was 1 microgram/L. Reference intervals (mean +/- SD) for kappa/lambda ratios in sera from 100 apparently healthy adults were 2.34 +/- 0.80 for IgG, 1.59 +/- 0.40 for IgA, and 1.86 +/- 0.76 for IgM.     

Simultaneous measurement of total and IgA-conjugated alpha 1-microglobulin by a combined immunoenzyme/immunoradiometric assay technique

alpha 1-Microglobulin (alpha 1m), a glycoprotein (Mr = 30,000) found in serum and urine, is also present in serum conjugated to monomeric IgA (alpha 1-m-IgA). We have developed a simultaneous enzyme-linked immunoenzyme/immunoradiometric assay that involves three different monoclonal antibodies. Assay of serial dilutions of serum and urine demonstrated parallelism. Normal mean concentrations in serum (n = 75) were: total alpha 1m, 2.33 mumol/L; alpha 1m-IgA, 1.24 mumol/L; unconjugated (free) alpha 1m, 1.09 mumol/L; molar ratio (alpha 1m-IgA/total alpha 1m), 0.53. The mean concentration of alpha 1m in eight urine specimens from normal individuals was 0.19 mumol/L, with no detectable alpha 1m-IgA. A low urinary pH does not significantly affect assay results, unlike assays of beta 2-microglobulin. In patients with myeloma-related renal disease, total and free alpha 1m values for serum correlated well with values for creatinine and beta 2-microglobulin in serum.     

Enhanced survival in Pseudomonas aeruginosa septicemia associated with high levels of circulating antibody to Escherichia coli endotoxin core.

We studied the relationship between serum antibodies to the cross-reactive endotoxin core of Escherichia coli and survival following Pseudomonas aeruginosa septicemia. Core glycolipid was purified from the outer cell membrane of a uridine diphosphate galactose 4-epimerase-deficient rough mutant E. coli (J5 strain), characterized, and used as the antigen in a quantitative enzyme-linked immunosorbent assay (ELISA) to measure core-specific IgG and IgM antibodies. 43 patients with Pseudomonas septicemia, among whom there was a mortality of 42%, were evaluated. Core-specific antibody concentrations in acute sera ranged from 1 to 49 micrograms/ml in the case of IgG and from 1 to 200 micrograms/ml for IgM. Core-specific antibodies of both isotypes were higher in patients who survived compared with those who succumbed to their septicemias (mean, microgram/ml +/- SEM, 26 +/- 3 vs. 14 +/- 4, P = 0.005 for IgG, and 55 +/- 12 vs. 18 +/- 5, P = 0.009 for IgM). Although total IgG levels were also higher in acute sera from survivors compared with nonsurvivors (mean, mg/dl +/- SEM, 1,120 +/- 99 vs. 694 +/- 119, P = 0.004), total IgM levels were virtually identical in the two groups (146 +/- 23 vs. 148 +/- 48, P = 0.52). Conversely, patients with core-specific IgG levels greater than 10 micrograms/ml at the onset of septicemia had better survival than those with levels less than 10 micrograms/ml (79 vs. 14%, P less than 0.001), and patients with core-specific IgM levels greater than 30 micrograms/ml had better survival than those with levels less than 30 micrograms/ml (81 vs. 44%, P = 0.01). In comparison, patients with total IgG levels greater than 1,000 mg/dl also had better survival than those with levels less than 1,000 mg/dl (82 vs. 42%, P = 0.01), while those with total IgM levels greater than 150 mg/dl showed somewhat less improvement in survival compared with those with levels less than 150 mg/dl (71 vs. 50%, P = 0.12). Core-specific IgM was highly correlated with core-specific IgG (r = 0.52), but not with type-specific anti-lipopolysaccharide (r = 0.13) or anti-toxin A (r = 0.12) antibodies, or with total IgG (r = 0.28) or IgM (r = 0.31). In contrast, core-specific IgG correlated somewhat more closely with type-specific antibodies (r = 0.36), and with total IgG (r = 0.51) and IgM (r = 0.52). Stepwise linear discriminant analysis indicated that type-specific antibody levels were the best predictor of outcome, among those antibodies examined, followed by anti-core IgM. Although anti-core IgG, anti-toxin A, and total IgG levels all correlated individually with survival, none augmented the prognostic power of type-specific antibodies in combination with anti-core IgM, which together predicted outcome accurately 73.5% of the time. Host factors not significantly associated with anti-core antibody levels included rapidly fatal underlying disease, age, sex, leukopenia, and prior treatment with cytotoxic drugs. In contrast, prior steroid therapy was associated with low levels of both core-specific IgG and IgM (P < 0.05). These data suggest cross-protective activity against P. aeruginosa septicemia of naturally occurring antibodies to the endotoxin core of E. coli. Anti-core antibodies, particularly of the IgM isotype appear to augment the more specific protective immunity engendered by antibodies to the O-specific side chains of Pseudomonas lipopolysaccharides. This cross-protective immunity likely applies to other Gram-negative pathogens as well.     

A human T cell lymphoma secreting an immunoglobulin E specific helper factor.

An 8-yr-old nonallergic girl with non-Hodgkin's lymphoma had markedly elevated serum IgE at presentation (greater than 10,000 IU/ml), negative skin tests to a battery of 24 common allergens, and no evidence of parasitic infestation. Serum levels of IgG, IgA, and IgM were normal. Remission after cytotoxic chemotherapy was accompanied by a marked reduction in serum IgE levels (to less than 200 IU/ml) with no change in the level of serum IgG, IgM, or IgA. Recurrence of the lymphoma 7 mo after remission was accompanied by an isotype specific rise in serum IgE (to 3,850 IU/ml). Isoelectric focusing revealed that the IgE was polyclonal. Phenotypic analysis of the lymphoma obtained during relapse revealed all (greater than 98%) cells to be T3+, T4+, and T8+. Incubation of lymphoma cells with human myeloma IgE followed by immunosorbent purified fluorescein tagged goat anti-human IgE (anti-IgE PS-adsorbed over IgE ADZ) stained 25% of the cells. In contrast, less than 1% of the cells were stained after incubation with human IgG followed by fluorescein conjugated goat anti-human IgE. Supernatants from lymphoma cells (5 X 10(6)/ml, 48 h) enhanced IgE production in B cells derived from four patients with allergic rhinitis (mean +/- SD picograms per milliliter of net IgE 930 +/- 320 in unstimulated cultures versus 2,450 +/- 650 in cultures stimulated with lymphoma supernatants; P less than 0.01) but did not induce IgE synthesis in B cells from two normal subjects that synthesized no IgE spontaneously. Lymphoma supernatants failed to enhance IgG synthesis by B cells of both allergic and nonallergic subjects. These results indicate that a T cell lymphoma comprised of cells bearing Fc receptors for IgE with a phenotype characteristic of immature T cells (i.e., T3+, T4+, T8+) exhibited IgE specific helper function. This lymphoma may represent the monoclonal expansion of a subpopulation of IgE specific helper T cells.     

Laser immunonephelometry reference intervals for eight serum proteins in healthy children.

Eight serum proteins were analyzed with the Behring nephelometer in samples from 479 healthy French children, ages three to 16 years. Girls had higher concentrations of IgM and albumin than boys had. Age appeared to be a main factor of variation for the proteins tested. Reference intervals are presented for IgG, IgA, IgM, albumin, transthyretin (prealbumin), retinol-binding protein, alpha 1-acid glycoprotein, and C-reactive protein. The significance of increased concentrations of C-reactive protein within a community is discussed.     

Profile of renal permselectivity by simultaneous enzyme-linked immunosorbent assay of albumin, transferrin, IgG, and alpha 1-microglobulin with a new microplate reader.

A competitive enzyme-linked immunosorbent assay (ELISA) is described for determining a renal permselectivity profile involving the urinary proteins albumin, transferrin, IgG, and alpha 1-microglobulin (alpha 1-m). The ELISA reader uses a computer-controlled array of multiplexed light-emitting diode (LED)-photodiode pairs for rapid measurements of absorbance on microplates. A 3,3'-dimethylnaphthidine reagent adapts the 3,5,3',5'-tetramethylbenzidine chromophore to monochromatic LED emission at 550 nm. We applied this ELISA to the determination of renal permselectivity in healthy children and young adults and in children with insulin-dependent diabetes mellitus. The geometric means (and SD) of protein excretion rates in a group of 85 normal subjects were as follows: albumin, 3.5 micrograms/min (1.83); transferrin, 173 ng/min (2.76); IgG, 1.11 micrograms/min (2.22), and alpha 1-m, 0.98 microgram/min (2.36).