Long-Term Persistence and Relevant Therapeutic Impact of High-Titer Viral-Neutralizing Antibody in a Convalescent COVID-19 Plasma Super-Donor: A Case Report

A convalescent, non-severe, patient with COVID-19 was enrolled as a hyper-immune plasma voluntary donor by the Immuno-Hematology and Transfusion Unit of the Regina Elena National Cancer Institute in Rome, under the TSUNAMI national study criteria. During a nearly 6-month period (May-October 2020), the patient was closely monitored and underwent four hyperimmune plasma collections. Serum SARS-CoV-2 (anti-S + anti-N) IgG and IgM, anti-S1 IgA, and neutralizing titers (NTs) were measured. Anti-SARS-CoV-2 antibody levels steadily decreased. No correlation was found between anti-S/anti-N IgG and IgM levels and viral NT, measured by either a microneutralization test or the surrogate RBD/ACE2-binding inhibition test. Conversely, NTs directly correlated with anti-S1 IgA levels. Hyperimmune donor plasma, administered to five SARS-CoV-2 patients with persistent, severe COVID-19 symptoms, induced short-term clinical and pathological improvement. Reported data suggest that high NTs can persist longer than expected, thus widening hyperimmune plasma source, availability, and potential use. In vitro RBD/ACE2-binding inhibition test is confirmed as a convenient surrogate index for neutralizing activity and patients' follow-up, suitable for clinical settings where biosafety level 3 facilities are not available. IgA levels may correlate with serum neutralizing activity and represent a further independent index for patient evaluation.

Oral immunoglobulin for preventing necrotizing enterocolitis in preterm and low birth weight neonates

BACKGROUND

Necrotizing enterocolitis (NEC) is the most common emergency involving the gastrointestinal tract occurring in the neonatal period. There have been published reports that suggest that oral immunoglobulins (Ig)A and IgG produce an immunoprotective effect in the gastrointestinal mucosa.

OBJECTIVES

To determine the effect of oral immunoglobulin on the incidence of necrotizing enterocolitis and other complications in preterm or low birth weight (or both) neonates.

SEARCH METHODS

We used the standard search strategy of the Cochrane Neonatal Group. We searched the Cochrane Central Register of Controlled Trials (CENTRAL, The Cochrane Library 2016, Issue 1), PubMed (1966 to January 2016), CINAHL (1982 to January 2016) and EMBASE (1980 to January 2016) and conference proceedings.

SELECTION CRITERIA

All randomized or quasi-randomised controlled trials where oral immunoglobulins were used as prophylaxis against NEC in preterm (less than 37 weeks' gestation) or low birth weight (less than 2500 gram), or both, neonates.

DATA COLLECTION AND ANALYSIS

We performed data collection and analysis in accordance with the standard methods of the Cochrane Neonatal Review Group.

MAIN RESULTS

The search identified five studies on oral immunoglobulin for the prevention of NEC of which three met the inclusion criteria. In this review of the three eligible trials (including 2095 neonates), the oral administration of IgG or an IgG/IgA combination did not result in a significant reduction in the incidence of definite NEC (typical risk ratio (RR) 0.84, 95% confidence interval (CI) 0.57 to 1.25; typical risk difference (RD) -0.01, 95% CI -0.03 to 0.01; 3 studies, 1840 infants), suspected NEC (RR 0.84, 95% CI 0.49 to 1.46; RD -0.01, 95% CI -0.02 to 0.01; 1 study, 1529 infants), need for surgery (typical RR 0.21, 95% CI 0.02 to 1.75; typical RD -0.03, 95% CI -0.06 to 0.00; 2 studies, 311 infants) or death from NEC (typical RR 1.10, 95% CI 0.47 to 2.59; typical RD 0.00, 95% CI -0.01 to 0.01; 3 studies, 1840 infants).

AUTHORS' CONCLUSIONS

Based on the available trials, the evidence does not support the administration of oral immunoglobulin for the prevention of NEC. There are no randomized controlled trials of oral IgA alone for the prevention of NEC.

Streptococcus pneumoniae antibody titres in patients with primary antibody deficiency receiving intravenous immunoglobulin (IVIG) compared to subcutaneous immunoglobulin (SCIG)

Intravenous immunoglobulin (IVIG) and subcutaneous immunoglobulin (SCIG) are effective in the treatment of patients with primary antibody deficiency disorders (PAD). The purpose of this study was to evaluate Streptococcus pneumoniae (Spn) antibody titres to 14 serotypes in patients receiving IVIG compared to SCIG and to correlate Spn antibody levels to clinical outcome. The doses of immunoglobulin (Ig)G/kg/month were similar in both IVIG and SCIG groups. In 11 patients treated with IVIG, Spn antibody titres were ≥ 1·3 μg/ml to 99·4 ± 2·1% of the 14 serotypes at peak IVIG but decreased to 66·9 ± 19·8% at trough IVIG. Loss of Spn titres ≥ 1·3 μg/ml was most frequent for Spn serotypes 1, 4, 9V and 23. This correlated with lower Spn antibody titres to these serotypes at peak IVIG compared to the other serotypes. In 13 patients treated with SCIG, Spn antibody titres were protective to 58·2 ± 23·3% of the serotypes 3-5 days after infusion, similar to trough IVIG. Similarly, the Spn serotypes with the least protective percentages were the same as the ones observed in trough IVIG. There were no annualized serious bacterial infections (aSBI) in either group. However, there were significantly decreased annualized other infections (aOI) in the SCIG group compared to the IVIG-treated group, 0·8 ± 0·7 versus 2·2 ± 1·2 infections/patient/year (P = 0·004). Breakthrough aOI did not correlate with protective or higher serum Spn antibody titres.

The protective effects of IgM-enriched immunoglobulin and erythropoietin on the lung and small intestine tissues of rats with induced sepsis: biochemical and histopathological evaluation

CONTEXT

Sepsis continues to be a significant problem for critical care patients.

OBJECTIVE

To evaluate the protective effects of IgM-enriched immunoglobulin and erythropoietin on pulmonary and small intestine tissues in a rat model of intra-abdominal sepsis induced via the cecal ligation and puncture (CLP) method.

MATERIALS AND METHODS

Male Sprague-Dawley rats were used. Control group (n = 6): surgical procedure was not performed. Laparotomy was only performed in the sham group (n = 6) and CLP was only performed in the sepsis (CLP) group (n = 30). After erythropoietin (2000 U/kg, intraperitoneal) was given in the sepsis + erythropoietin (CLP + EPO) group (n = 30), IgM-enriched immunoglobulin (600 mg/kg, intraperitoneal) was given in the sepsis + pentaglobin (CLP + PEN) group (n = 30), CLP was created. Intracardiac blood samples were collected for biochemical analysis; lung and small intestine tissue samples were removed for histopathological evaluation.

RESULTS

Plasma TNF-α levels (pg/ml) were similar among CLP, CLP + EPO, and CLP + PEN groups (204.0 ± 52.4, 198.5 ± 17.3, and 214.6 ± 93.6, respectively). The CLP group had higher plasma IL-1β levels (pg/ml) compared with CLP + EPO and CLP + PEN groups (325.1 ± 134.1, 164.3 ± 25.6, and 186.3 ± 26.0, respectively) (p < 0.05). Rats in CLP + EPO and CLP + PEN groups had abolished histopathologic appearance of lung and small intestine tissues compared with rats in the CLP group.

DISCUSSION AND CONCLUSION

Our findings support the use of EPO and IgM-enriched immunoglobulin in the prevention of lung and small intestine injuries associated with sepsis.

Pentaglobin as an adjunct therapy in very low birthweight neonates with nosocomial sepsis

OBJECTIVE

To evaluate the effect of pentaglobin treatment on clinical and laboratory parametres and the major morbidities in very low birthweight neonates with nosocomial sepsis before and after pentaglobin treatment.

METHODS

The prospective interventional study was conducted from January 1 to December 31, 2010, at the neonatal intensive care unit (NICU) of the Bakirköy Dr. Sadi Konuk Training and Research Hospital, Istanbul, Turkey. Pentaglobin was initiated on the day of diagnosis of nosocomial sepsis to 13 pre-term neonates as a support therapy in addition to antibiotics; 5 ml/kg per day of pentaglobin was infused over a 4-hour period on 3 consecutive days. Clinical and laboratory parametres and major morbidities were recorded before and after pentaglobin treatment and compared using NCSS software.

RESULTS

Of the total, 8 (66%) were females and 5 (40%) males. Following pentaglobin therapy, the immature-to-total neutrophil ratio and C-reactive protein levels were significantly decreased, and the capillary pH and base excess were significantly increased (p < 0.05). The axillary temperature, non-invasive blood pressure, haemoglobin, leukocyte, and thrombocyte values did not significantly differ before and after treatment (p > 0.05). Coagulase-negative staphylococci (n = 3; 23%), Klebsiella pneumoniae (n = 2; 15.3%), and Pseudomonas aeruginosa (n = 1; 7.7%) were identified in blood cultures. The presence of intraventricular haemorrhages, necrotising enterocolitis, periventricular leukomalacia, and patent ductus arteriosus was not changed following the treatment. Adverse effects and mortality were not observed during or after the therapy.

CONCLUSION

Pentaglobin treatment of nosocomial sepsis could be used as an adjunct therapy without any adverse short-term reactions, even in very low birthweight pre-term infants.

[Immune reaction to anesthesia and surgical injury in neonatal infants]

The impact of surgical injury and anesthesia on cellular and humoral immunity parameters was studied in neonatal infants with surgical pathology. These were found to have immunosuppressive activity, which appeared as evolving absolute lymphopenia and a reduction in the serum concentration of IgG. The magnitude of these changes depends on the functional state of the immune system in the preoperative period and is higher in infants with signs of an infectious-inflammatory process in the preoperative period, which increases the risk of septic complications. Preoperative immune replacement therapy with intravenous immunoglobulins (Pentaglobin) in neonates with severe developmental defects stops a fall in the level of cytotoxic lymphocytes in the early postoperative period.

[Intranasal administration of immunoglobulins--perspectives for use in medical practice]

Effectiveness of topical use of immunoglobulines in respiratory infections along with preparations for parenteral use is discussed. Immunoglobuline preparations for intranasal use (drops, spays, aerosols) should take place among preparations intended for prevention and treatment of influenza, parainfluenza, respiratory syncitial virus infection and others. Potential to intranasal use of complex immunoglobulin preparation containing polymeric and monomeric antibodies of different isotypes is also discussed.

Polyclonal intravenous immunoglobulin for the treatment of severe sepsis and septic shock in critically ill adults: a systematic review and meta-analysis

OBJECTIVES

To systematically review the literature to assess whether adjunctive therapy with polyclonal intravenous immunoglobulin (ivIg) reduces mortality among critically ill adults with severe sepsis and septic shock.

DATA SOURCE

MEDLINE, EMBASE, and Cochrane Central Register of Controlled Trials databases; the meta-register of controlled trials; and the Medical Editors Trial Amnesty register.

STUDY SELECTION

Prospective randomized clinical trials (RCTs) evaluating ivIg treatment in critically ill adults with severe sepsis or septic shock were included. Two reviewers conducted assessment of suitability for inclusion.

DATA EXTRACTION

Two authors independently determined the validity of included studies and extracted data.

DATA SYNTHESIS

The effect of ivIg on all-cause mortality was quantified using a fixed-effect meta-analysis.

RESULTS

Fourteen RCTs published between 1988 and 2006 were included. Most were small, used relatively low doses of ivIg, and included predominantly surgical patients with Gram-negative infections. There was a significant reduction in mortality associated with use of ivIg treatment with a pooled odds ratio of 0.66 (95% confidence interval 0.53-0.83; p < .0005). In general, a greater treatment effect was seen among studies of lower methodological quality, studies using higher doses of ivIg, and studies that did not use albumin as a control. There was evidence of between-study heterogeneity (chi-square p = .009), and this was at least moderate as measured by the I2 value (I2 = 53.8%). When only high-quality studies were pooled, the odds ratio for mortality was 0.96 (95% confidence interval 0.71-1.3; p = .78).

CONCLUSIONS

This meta-analysis demonstrates an overall reduction in mortality with the use of ivIg for the adjunctive treatment of severe sepsis and septic shock in adults, although significant heterogeneity exists among the included trials and this result was not confirmed when only high-quality studies were analyzed. These data warrant a well-designed, adequately powered, and transparently reported clinical trial.

IgMA-enriched immunoglobulin in neutropenic patients with sepsis syndrome and septic shock: A randomized, controlled, multiple-center trial*

OBJECTIVE

To evaluate the effect of intravenous IgMA-enriched immunoglobulin (ivIGMA) therapy on mortality in neutropenic patients with hematologic malignancies and sepsis syndrome or septic shock.

DESIGN

Multiple-center, prospective randomized, controlled study.

SETTING

Six university hospitals in Germany.

PATIENTS

Patients were 211 neutropenic patients with sepsis syndrome or septic shock after chemotherapy for severe hematologic disorders between 1992 and 1999.

INTERVENTIONS

Patients received 1300 mL of ivIGMA (7.8 g IgM, 7.8 g IgA, and 49.4 g IgG) infused intravenously within a period of 72 hrs or human albumin according to the same schedule as ivIGMA.

MEASUREMENTS AND MAIN RESULTS

All-cause mortality at 28 days, sepsis-related mortality at 28 days, all-cause mortality at 60 days, mortality from septic shock, and mortality from microbiologically proven Gram-negative sepsis and septic shock were recorded. Immunoglobulin had no benefit over human albumin. The 28-day mortality rate was 26.2% and 28.2% in the ivIGMA and control patients, respectively (difference, 2.0% [95% confidence interval, -10.2 to 14.2 percentage points]). Likewise, the 60-day mortality rate did not differ between both arms (29.6% vs. 34.7% in the ivIGMA and control patients, respectively). Mortality rates in patients with sepsis syndrome (17.1% vs. 16.7%) and septic shock (51.9% vs. 54.8%) were also found to be similar between both groups.

CONCLUSIONS

Intravenous ivIGMA had no beneficial effects in neutropenic patients with hematologic malignancies and sepsis syndrome and septic shock.

Pentaglobin in steroid-resistant severe acute respiratory syndrome

SETTING

The treatment of severe acute respiratory syndrome (SARS) is at best controversial, although there is considerable anecdotal experience to show the benefits of corticosteroid therapy for selected patients. Some patients deteriorate relentlessly despite treatment with antibiotic, corticosteroid and mechanical ventilation.

OBJECTIVE

To attempt to determine the clinical efficacy of pentaglobin, an IgM-enriched immunoglobulin preparation, on 12 severe SARS patients who continued to deteriorate despite corticosteroid and ribavirin therapy.

DESIGN

Retrospective analysis of daily quantitative and radiographic data on the cohort in a regional teaching hospital.

RESULTS AND CONCLUSION

There was significant improvement in radiographic scores, when compared with day 1, on days 5, 6 and 7 (P < 0.05) after commencement of pentaglobin treatment. Similarly, there was significant improvement in oxygen requirement, when compared with day 1, on days 6 and 7 (P < 0.05) after commencement of pentaglobin treatment. There were no reported adverse events attributable to pentaglobin administration. Ten patients made an uneventful recovery after treatment. One elderly man died from cardiorespiratory arrest despite clinical and radiological improvement, and another patient is making good progress. Pentaglobin is safe and probably effective in the treatment of steroid-resistant SARS. A double-blind placebo-controlled study should therefore be considered.

Passive protection with immunoglobulin A antibodies against tuberculous early infection of the lungs

We report on a new approach toward protection against tuberculosis, based on passive inoculation with immunoglobulin A (IgA) antibodies. In a mouse model of tuberculous lung infection, intranasal inoculations of mice with an IgA monoclonal antibody (mAb) against the alpha-crystallin antigen of Mycobacterium tuberculosis reduced up to 10-fold the lung bacterial counts at nine days after either aerosol- or intranasal challenge. This effect involved synergism between mAb inoculations shortly before and 3 days after infection. Monomeric IgA reduced the colony-forming unit counts to the same extent as the polymeric IgA, suggesting antibody targeting to Fcalpha, rather than poly-immunoglobulin receptors on infected lung macrophages. The protective effect was of short duration, presumably due to the rapid degradation of the intranasally applied IgA. Our results provide evidence of an alternative approach which could be further developed toward immunoprophylaxis against tuberculosis in immunocompromised subjects.

Oral immunoglobulin for preventing necrotizing enterocolitis in preterm and low birth-weight neonates

BACKGROUND

Necrotizing enterocolitis (NEC) is the most common emergency of the gastrointestinal tract occurring in the neonatal period. There have been published reports which suggest that oral immunoglobulins IgA and IgG produce an immunoprotective effect in the gastrointestinal mucosa. This systematic review was undertaken to clarify the issue.

OBJECTIVES

To assess whether oral immunoglobulin administered to preterm and low birth-weight neonates reduces the incidence of necrotizing enterocolitis without adverse effects.

SEARCH STRATEGY

The databases MEDLINE, CINAHL, EMBASE (1966 to October 26, 2003) and the Cochrane Central Register of Controlled Trials (CENTRAL, The Cochrane Library, Issue 3, 2003) were searched. Proceedings of the Perinatal Society of Australia and New Zealand were hand searched. The computer neonatal discussion site 'Nicu Net' was also used. Additionally, all references in the identified trials were checked and authors were contacted to request any additional published or unpublished data. No new trials were identified.

SELECTION CRITERIA

All randomised or quasi-randomised controlled trials where oral immunoglobulins were used as prophylaxis against necrotizing enterocolitis in preterm (<37 weeks gestation) and/or low birth-weight (<2500 gms) neonates.

DATA COLLECTION AND ANALYSIS

The procedures of the Cochrane Neonatal Review Group (CNRG) were used. The two reviewers independently assessed the trials for their methodological quality and subsequent inclusion in the review. Relative risk (RR), risk difference (RD), and number needed to treat (NNT) were used in the analysis.

MAIN RESULTS

Five studies on oral immunoglobulin for the prevention of necrotizing enterocolitis were identified of which three met the inclusion criteria. In this review of the three eligible trials (including a total of 2095 neonates) the oral administration of IgG or an IgG/IgA combination did not result in a significant reduction in the incidence of definite NEC [RR 0.84 (95% CI 0.57, 1.25), RD -0.01 (95% CI -0.03, 0.01)], suspected NEC [RR 0.84 (95% CI 0.49, 1.46), RD -0.01 (95% CI -0.02, 0.01)], need for surgery [RR 0.21 (95% CI 0.02, 1.75), RD -0.03 (95% CI -0.06, 0.00)] or death from NEC [RR 1.10 (95% CI 0.47, 2.59), RD 0.00 (95% CI -0.01, 0.01)].

REVIEWER'S CONCLUSIONS

Based on the available trials, the evidence does not support the administration of oral immunoglobulin for the prevention of NEC. There are no randomised controlled trials of oral IgA alone for the prevention of NEC.

[Experience with kipferon use in the treatment of patients with pulmonary tuberculosis]

Kipferon that is a combination of recombinant human (2-interferon and a complex of immunoglobulins G, M and A, was used in suppositories as an auxiliary agent in the routine chemotherapy in 36 new cases of pulmonary tuberculosis. A control group included 19 patients identical in sex, age, and the pattern of pulmonary tuberculosis. The clinical, X-ray, and laboratory indices (primarily cellular immunity) were studies before and 1 and 3 months after treatment. The beneficial effect of kipferon was manifested by a more rapid arrest of symptoms of total intoxication eliminated after 2 weeks in 39% of patients in the experimental group and only in 21% in the controls. Normalization of blood parameters occurred following a month in 58.3 and 47% of patients, respectively. Mycobacteria tuberculosis disappeared in the sputum smears following a month of treatment in 62% of those isolating bacteria in the experimental group and only in 37.5% in the controls (P > 0.1; t = 1.6). Positive lung X-ray changes as resolved infiltration, the reduction and closure of caverns were more pronounced in the patients of the experimental group. The most characteristic change in the parameters of cellular immunity during kipferon was a short (as long as 1-1.5 months) decrease in RBT to FGA, which was noted in 47% and 6.7% of patients in the experimental and control groups, respectively (P < 0.01) and which was followed by an increase in the count of CD8+ cytotoxic lymphocytes. This is indicative of the enhancement of these mechanisms of immunity and a reduced need of enhancing or maintaining the activity of proliferative reactions of immunocompetent cells under the conditions of a favourable influence on the course of tuberculous infection.

[Unrelated donor stem cell transplantation in children: low toxicity using a GvHD-prophylaxis regimen with CSA, MTX, metronidazole,iv-immunoglobulin and ATG]

BACKGROUND

Unrelated donor (UD) hematopoietic stem cell transplantation (HSCT) is accepted as a therapy for leukaemic diseases and varying inborn diseases if a suitable related donor cannot be found. The goal of immunosuppressive therapy with UD-HSCT is an effective prevention of graft-versus-host-disease (GvHD) on one hand. On the other hand an optimal balance with immunocompetence of the transplanted bone marrow is desirable in order to prevent graft failure, infection and, in the case of leukaemic diseases, potentially control the underlying disease.

PATIENTS AND METHODS

Between 1992 and 2000 49 patients aged 11 months to 16.7 years received an UD-HSCT in Hamburg. Underlying diseases were leukaemia or MDS in 35, of these ALL in 21, hemophagocytic lymphohistiocytosis (HLH) in 9, immunodeficiency or inborn error of metabolism in 5 patients. GvHD-prophylaxis consisted of a combination of Cyclosporin A (CSA), methotrexate (MTX), metronidazole, IgM-enriched iv-immunoglobulin (ivIg) (Pentaglobin(R)) or ivIgG and anti-thymocyte-globulin (ATG). Within the same time span 10 patients with ALL received a matched related donor HSCT (MRD-HSCT). GvHD-prophylaxis in these patients was done without ATG in 8 of 10 cases. UD-HSCT were analyzed for survival, relapse and toxicity. Probability of survival of the patients with ALL after UD-HSCT was compared with results of MRD-HSCT in children with ALL.

RESULTS

The Kaplan-Meier estimates of three year overall-survival (OS) were 74 % for all patients. Probability of disease-free survival (DFS) at three years was 62 % for leukaemia/MDS-patients and 100 % for the HLH-patients. Acute GvHD (aGvHD) grades II or III occurred in 51 % of patients. Chronic GvHD (cGvHD) occurred in 22 % of patients. There were 5 cases of treatment-related mortality (TRM). Probability of DFS for patients with ALL at three years was 65 % after UD-HSCT and 30 % in the patients after MRD-HSCT.

CONCLUSIONS

UD-HSCT in children is an effective and safe therapy. A GvHD-prophylaxis regimen combining the standard immunosuppressive agents CSA and MTX with ivIg, metronidazole and serotherapy using ATG may result in a low incidence of severe GvHD-complications and low TRM rate without increase in relapse rates.

Development of intestinal immunoglobulin absorption and enzyme activities in neonatal pigs is diet dependent

Uptake of colostrum just after birth is essential to stimulate intestinal growth and function, and in many species, including pigs, colostrum also provides immunological protection via the absorption of immunoglobulin G (IgG). In this study, intestinal growth, IgG absorptive capacity and enzyme activities were investigated in newborn pigs in response to different diets. Newborn piglets were bottle-fed porcine colostrum (PC), bovine colostrum (BC), porcine plasma (PP), porcine milk (PM), bovine colostrum containing porcine plasma (BCP) or a milk replacer (MR) every 3 h (15 mL/kg) for up to 2 d. Bovine serum albumin (BSA) was added to the diets as a macromolecule marker. The percentage of absorbed BSA just after birth was highest for piglets fed the PC diet (30-50%), lower for those fed the BC and BCP diets (23-30%) and lowest for the PP, PM and MR diet-fed piglets (7-20%, P < 0.05 relative to those fed colostrum). Porcine IgG was absorbed more efficiently than bovine IgG. Intestinal closure occurred earlier in MR and BCP piglets (within 12 h after birth) than in PC pigs. At 2 d of age, intestinal mucosal weight (+120% increase from birth) and villus morphology were similar in the PC, BCP and MR groups. All 3 groups also had increased aminopeptidase A activity compared with values at birth (+100% increase). Compared with PC pigs, the BCP group had higher sucrase and maltase activities (+50% and +200%, respectively) and lower aminopeptidase N activity (-50%, P < 0.05). Similarly, MR pigs showed elevated sucrase activity (+40%) and lowered maltase, lactase and aminopeptidase N activities (-20% to -50%, P < 0.05) compared with PC pigs. We conclude that porcine and bovine colostrum contain factors that stimulate the intestinal endocytotic and enzymatic capacity in newborn pigs. A milk replacer can produce normal gut growth, but may be inefficient in mediating normal macromolecule transport and disaccharidase activity. Bovine colostrum mixed with porcine plasma proteins may be a useful substitute for porcine colostrum in artificial rearing of newborn pigs.

IgA antibodies for cancer therapy

Antibody-based therapy is a new treatment option for selected tumor patients. Today, human IgG(1) is the most widely used isotype, because it effectively activates human complement, recruits NK cells for ADCC, and has an extended plasma half life. In recent work, however, neutrophils--the most populous cytotoxic cells in humans--were more effectively recruited by human IgA than by IgG antibodies. IgA antibodies may have the additional advantages of forming natural dimers with improved signaling capacity on tumor cells, and being actively transported into mucosal secretions with the potential for improved targeting of certain carcinomas from the luminal surface.

Oral immunoglobulin for preventing necrotizing enterocolitis in preterm and low birth-weight neonates

BACKGROUND

Necrotizing enterocolitis (NEC) is the most common emergency of the gastrointestinal tract occurring in the neonatal period. There have been published reports which suggest that oral immunoglobulins IgA and IgG produce an immunoprotective effect in the gastrointestinal mucosa. This systematic review was undertaken to clarify the issue.

OBJECTIVES

To assess whether oral immunoglobulin administered to preterm and low birth-weight neonates reduces the incidence of necrotizing enterocolitis without adverse effects.

SEARCH STRATEGY

The databases MEDLINE, CINAHL, Embase and the Cochrane Controlled Trials Register were searched. The text words 'necrotising enterocolitis OR necrotizing enterocolitis' AND 'immunoglobulin' with constraints 'neonate OR infant' were used. Proceedings of the Perinatal Society of Australia and New Zealand were hand searched. The computer neonatal discussion site 'Nicu Net' was also used. Additionally, all references in the identified trials were checked and authors were contacted to request any additional published or unpublished data.

SELECTION CRITERIA

All randomized or quasi-randomized controlled trials where oral immunoglobulins were used as prophylaxis against necrotizing enterocolitis in preterm (<37 weeks gestation) and/or low birth-weight (<2500 gms) neonates.

DATA COLLECTION AND ANALYSIS

The procedures of the Cochrane Neonatal Review Group (CNRG) were used. The two reviewers independently assessed the trials for their methodological quality and subsequent inclusion in the review. Relative risk (RR), risk difference (RD), and number needed to treat (NNT) were used in the analysis.

MAIN RESULTS

Five studies on oral immunoglobulin for the prevention of necrotizing enterocolitis were identified of which three met the inclusion criteria. In this review of the three eligible trials (including a total of 2095 neonates) the oral administration of IgG or an IgG/IgA combination did not result in a significant reduction in the incidence of definite NEC [RR 0.84 (95% CI 0.57, 1.25), RD -0.01 (95% CI -0.03, 0.01)], suspected NEC [RR 0.69 (95% CI 0.42, 1.13), RD -0.01 (95% CI -0.03, 0.00)], need for surgery [RR 0.21 (95% CI 0.02, 1.75), RD -0.03 (95% CI -0.06, 0.00)] or death from NEC [RR 1.10 (95% CI 0.47, 2.59), RD 0.00 (95% CI -0.01, 0.01)].

REVIEWER'S CONCLUSIONS

Based on the available trials, the evidence does not support the administration of oral immunoglobulin for the prevention of NEC. There are no randomised controlled trials of oral IgA alone for the prevention of NEC.

The overall concept: immunoglobulins as adjuvants for mediastinitis--does it make sense?

Supportive intravenous immunoglobulin (ivIg) treatment may reduce the incidence and severity of infections in a well-defined group of patients in intensive care, including those who have had cardiac surgery. Sternal wound infections and mediastinitis after cardiac surgery are to be investigated in the ATMI study with Pentaglobin. In this article I focus on optimising ivIg dosage, on likely mechanisms, on reasons why ivIg might improve a primarily gram-positive infection, and on the use of serial scoring as an endpoint in a trial of immunoglobulin.

Transmission of IgA and IgG monoclonal antibodies to mucosal fluids following intranasal or parenteral delivery

BACKGROUND

The efficacy by which passive antibodies can reach the lungs could be important for the outcome of immunotherapy of respiratory pulmonary infections. We examined how transmission to a number of mucosal sites is affected by the route of inoculation.

METHODS

Transmission of newly raised IgA class Mabs against mycobacterial surface antigens to saliva, lung or vaginal lavage, bile and serum of BALB/c mice was compared with existing IgG Mabs. ELISA was used for testing body fluids obtained 1-24 h after intranasal or intravenous inoculation and 1-7 days following back-pack tumour growth of hybridomas.

RESULTS

Intranasal inoculation resulted in a rapid rise and high levels of both IgA and IgG class Mabs in lung lavage. In contrast, following intravenous Mab injection or back-pack tumour growth of hybridoma cells, effective lung transmission was observed for the IgG1 and IgG2b MAbs, but not for the IgA Mabs. The secretory component was acquired by the transmitted IgA MAbs in the mucosal fluids, but not in the serum. Nevertheless, the time course of mucosal IgA antibody levels was similar to that of the tested IgG Mabs. Furthermore, the relative proportion of transmission to saliva and bile varied between individual Mabs indicating a role of tissue-specific, immunoglobulin class-unrelated mechanisms.

CONCLUSIONS

Intranasal, rather than parenteral inoculation of mice is required for the efficient delivery of IgA antibodies against respiratory pulmonary pathogens. Interestingly, IgA-secretory component complexing of intranasally applied Mabs did not significantly influence their persistence in the lungs.

[Successful management of systemic lupus erythematosus with IgM enriched immunoglobulins]

Systemic lupus erythematosus is a potentially life-threatening disease. Even the use of potent immunosuppressive drugs often barely controls the disease. In addition, treatment-related side effects are common due to the high doses of immunosuppressive drugs necessary. We report on two cases of acutely exacerbated systemic lupus erythematosus which were difficult to control with prednisone and cyclophosphamide. Both patients were additionally treated with IgM-enriched preparations of intravenous immunoglobulins. In both cases, the doses of the immunosuppressive drugs used could be significantly reduced. After nine treatment cycles, patients remained disease-free for a follow-up period of one year with only minimal immunosuppressive therapy. Our observation shows that IgM-enriched immunoglobulins can be used for therapy of systemic lupus erythematosus.

Passive IgA monoclonal antibody is no more effective than IgG at protecting mice from mucosal challenge with respiratory syncytial virus

Respiratory syncytial virus (RSV) is a mucosally restricted pathogen that can cause severe respiratory disease. Although parenteral administration of sufficient RSV-specific IgG can reduce severity of lower respiratory tract infection in high-risk infants, delivery of antibody by direct airway administration is an attractive alternative. Topical and parenteral administration of an IgA monoclonal antibody (MAb) specific for the RSV F glycoprotein was compared with an IgG MAb, specific for the same antigenic site, for ability to protect mice against RSV infection. Administration of RSV-specific IgG was more effective in reducing RSV titers in lung (4.6 log10 pfu/g) than IgA MAb (3.6 log10 pfu/g) when given intranasally immediately prior to infection (P=.005). RSV titers in the nose were reduced only by prophylactic administration of IgG parenterally. Therefore, topical administration of IgA is no more effective than topically administered IgG and is less effective than systemically administered IgG for protecting against RSV infection.

Gut mucosa barrier preservation by orally administered IgA-IgG to patients undergoing bone marrow transplantation: a randomised pilot study

Intensive cytotoxic therapy with bone-marrow transplantation (BMT) allows a potential cure for haematological malignancies. Protective strategies to minimise haematological toxicities have been successful and currently toxicity to the gastro-intestinal tract is the major cause of treatment-related morbidity and the dose-limiting factor that prevents further dose escalation. In a randomised, placebo-controlled trial we investigated whether an oral immunoglobulin preparation (IgA-IgG) can diminish intestinal toxicity with autologous BMT. IgA-IgG (n = 6) and placebo (n = 7) were orally administered from 1 day prior to the start until 1 week after the termination of the cytotoxic treatment (a total of 14 days). Intestinal toxicity was assessed by a 51Cr-EDTA absorption test for intestinal permeability and by the clinical criteria laid down by the WHO for the period before the start of the cytotoxic treatment, 1 day prior to stem-cell infusion and 4, 7, 10 and 14 days after stem-cell infusion. In the placebo group there was a significant increase in intestinal permeability on day 4 (P < 0.005) and on day 7 (P < 0.05) after stem-cell infusion, compared with the baseline, which was not seen for IgA-IgG. In addition, patients receiving IgA-IgG had significantly less intestinal permeability on day 4 (P < 0.05) and on day 7 (P < 0.05), compared with the placebo group. No significant, positive effect as regards clinical toxicity was observed. Oral administration of IgA-IgG to patients undergoing intensive cytotoxic therapy prior to BMT seems to have a protective effect on the gut mucosa barrier which is normally disrupted by this therapy.

Combined administration of IgA and IgG anti-Thy-1 antibodies enhances renal inflammation in rats

BACKGROUND

IgA nephropathy (IgAN) is the most common type of immunologically mediated glomerulonephritis (GN) and is characterized by deposition in the glomerular mesangium of IgA together with C3, C5b-9, and properdin. In patients, the codeposition of IgA together with IgG and/or IgM can lead to a more progressive course of disease. In Wistar rats, mesangial proliferative GN can be induced by the injection of mouse IgG anti-Thy-1 antibodies (ER4G). In contrast, the administration of mouse IgA anti-Thy-1 antibodies (ER4A) to rats results in isolated hematuria without detectable albuminuria and without detectable complement deposition.

METHODS

To investigate the effect of the combination of IgA and IgG on glomerular injury, Wistar rats were injected with a limiting dose of ER4G in the presence or absence of ER4A in a dose able to induce hematuria.

RESULTS

Although the limiting dose of ER4G or the dose of ER4A used did not induce significant albuminuria, the combination of ER4G and ER4A resulted in a synergistic increase in albuminuria. Microhematuria occurred in rats receiving either ER4A or ER4G alone or in combination. Although both ER4A or a limiting dose of ER4G induced minor increases in extracellular matrix expansion, the combination resulted in a pronounced, additive increased matrix expansion.

CONCLUSION

We conclude that in this model of IgA-mediated glomerulopathy, a selective complement-dependent synergistic renal injury is induced in Wistar rats by glomerular codeposition of mouse anti-Thy-1 monoclonal isotypes.

Use of a five-agent GVHD prevention regimen in recipients of unrelated donor marrow

A five-agent GVHD prophylaxis programme consisting of cyclosporin A, methotrexate, anti-thymocyte-globulin, pentaglobin and metronidazol was given to 48 recipients of unrelated donor marrow with chronic myelogenous leukemia, acute leukemia, myelodysplastic syndromes, and familiar lymphocytic hemophagocytosis of an average age of 33.5 (0.6-56) years. GVHD grades II-IV occurred in 18 patients (39%) and grades III-IV in five patients (11%). Chronic GVHD developed in nine patients (23%), three limited and six extensive. Fifteen patients died. Clinical relapse was detected in eight patients. Four patients died as a consequence of the underlying disease and subsequent treatment, 11 patients died of transplant-related causes. After a median follow-up of 19 months, the overall and disease-free survival are 67% and 62%, respectively. Survival by age is as follows: 0-19 years: 12/13 patients; 20-39 years: 14/25 patients; 40-59 years: 7/10 patients. The five-agent GVHD prophylaxis regimen is effective. Matched-unrelated donor transplants can be carried out safely in patients younger than 50 years of age. The results in patients younger than 20 years of age should encourage matched-unrelated donor transplants at earlier stages of the disease.

Role of immunoglobulin A monoclonal antibodies against P23 in controlling murine Cryptosporidium parvum infection

Cryptosporidium parvum is an important diarrhea-causing protozoan parasite of immunocompetent and immunocompromised hosts. Immunoglobulin A (IgA) has been implicated in resistance to mucosal infections with bacteria, viruses, and parasites, but little is known about the role of IgA in the control of C. parvum infection. We assessed the role of IgA during C. parvum infection in neonatal mice. IgA-secreting hybridomas were developed by using Peyer's patch lymphocytes from BALB/c mice which had been orally inoculated with viable C. parvum oocysts. Six monoclonal antibodies (MAbs) were selected for further study based on indirect immunofluorescence assay reactivity with sporozoite and merozoite pellicles and the antigen (Ag) deposited on glass substrate by gliding sporozoites. Each MAb was secreted in dimeric form and recognized a 23-kDa sporozoite Ag in Western immunoblots. The Ag recognized comigrated in sodium dodecyl sulfate-polyacrylamide gel electrophoresis with P23, a previously defined neutralization-sensitive zoite pellicle Ag. MAbs were evaluated for prophylactic or therapeutic efficacy against C. parvum, singly and in combinations, in neonatal BALB/c mice. A combination of two MAbs given prophylactically prior to and 12 h following oocyst challenge reduced the number of intestinal parasites scored histologically by 21.1% compared to the numbers in mice given an isotype-matched control MAb (P < 0.01). Individual MAbs given therapeutically in nine doses over a 96-h period following oocyst challenge increased efficacy against C. parvum infection. Four MAbs given therapeutically each reduced intestinal infection 34.4 to 42.2% compared to isotype-matched control MAb-treated mice (P < 0.05). One MAb reduced infection 63.3 and 72. 7% in replicate experiments compared to isotype-matched control MAb-treated mice (P < 0.0001). We conclude that IgA MAbs directed to neutralization-sensitive P23 epitopes may have utility in passive immunization against murine C. parvum infection.

Intranasally administered immunoglobulin for the prevention of rhinitis in children

OBJECTIVE

To determine the efficacy of intranasally administered immunoglobulin in preventing symptoms of rhinitis in children.

METHODS

Forty children ages 1 to 4 years who attended day-care centers in Turku, Finland, were enrolled in the double blind, placebo-controlled study. The children were randomly assigned to receive treatment with immunoglobulin, composed mainly of immunoglobulin A, or placebo, both administered as nasal sprays twice daily for 8 weeks. During this medication period and an additional 8-week follow-up period, the parents recorded the symptoms of the children daily in the diaries provided. One child who met an exclusion criterion was withdrawn from the study after a few days of medication.

RESULTS

During the 8-week medication period the 19 children in the immunoglobulin group had 42% fewer days with rhinitis than the 20 children receiving placebo (mean, 10.8 vs. 18.7 days; P=0.004). The total numbers of episodes of rhinitis in the immunoglobulin and placebo groups were 33 and 51, respectively. No significant differences were observed between the groups during the postmedication follow-up period.

CONCLUSIONS

Intranasal administration of immunoglobulin appears to be an effective method to prevent symptoms of rhinitis in children, and further studies of this approach are needed.

Cytokine responses of human blood monocytes stimulated with Igs

Using an in vitro system for stimulating human peripheral blood mononuclear cells (PBMC) with immobilized Ig, patterns of cytokine production as a function of different Ig classes and subclasses were elucidated. Wells were coated with IgA, IgG1, IgG2, IgG3 or IgG4. Equivalent protein content on surfaces of wells was demonstrated by a human kappa chain ELISA. Isolated human PBMC were added to Ig-coated wells and incubated for 24 hrs before supernatants were assayed for cytokines. The IgG subclasses showed differences in cytokine production stimulated from PBMC, with the relative stimulation for TNF alpha being IgG2 > or = IgG3 > or = IgG1 > IgG4 and for IL-6 production, IgG2 > or = IgG3 > IgG1 = IgG4. In contrast, the relative stimulation for IL-8 was IgG1 = IgG2 = IgG3 = IgG4. IgA caused less production of TNF alpha when compared to IgG2, but similar levels of IL-8. Such differences may have important implications in the pathogenesis of immune complex mediated diseases.

[Prevention of infections in patients with lymphoproliferative syndromes and myeloma by nebulization of an IgA concentrate]

Infection of the upper respiratory tract is a major cause of morbidity and mortality in patients with lymphoproliferative syndromes and multiple myeloma. Nebulizations with IgA tested in a randomized double blind trial to evaluate its efficacy to prevent respiratory infections in patients with lymphoproliferative syndromes and multiple myeloma. Forty nine patients were evaluated (chronic lymphocytic leukaemia, 22; multiple myeloma, 11; lymphoma, 8; HCL, 6; Waldenström and lymphoepiteliod tymoma, 1 patient each) were randomized to receive nebulizations every 12 hours during 3 months of IgA or placebo. Seven infectious episodes (4 respiratory tract infections) in 25 IgA treated patients and 25 episodes (16 respiratory tract infections) in 24 control patients were recorded (p <0.0002). Eighteen patients belonging to the treated group remained free of infections against only 5 from the control group (p < 0.001). No difference related to the grade of infections was observed between groups. The arithmetic media for the first infection observed in each group was 45.6 +/- 22.0 days for the IgA treated and 28.6 +/- 17.5 days for the placebo (p < 0.025). According to this study, IgA nebulization therapy was useful to prevent respiratory tract infections and also delay the onset of infection in patients with lymphoproliferative syndromes and myeloma.

An IgA, IgG and IgM-containing human immunoglobulin for oral administration to high-risk bottle-fed newborns. I. Immunochemical characterisation and antibody activity

Antibodies to a wide spectrum of infectious agents belonging to the IgA, IgM and IgG isotypes are thought to be one of the protective factors in human milk. Cow milk-fed newborns are at an increased risk of infections as well as of allergic diseases and of necrotising enterocolitis. A reasonable approach would be to add to the milk formula fed to them the immunoglobulins present in human milk. We developed a pasteurised immunoglobulin preparation from pooled donor plasma ('Orabulin') containing 75% IgG, 18% IgA and 6% IgM for feeding to high-risk bottle-fed babies. Its molecular composition was studied by HPLC and by SDS-PAGE. The levels of IgA, IgG and IgM antibodies in Orabulin were compared to these in the immunoglobulin fraction of human colostrum and an enrichment was found. It is suggested that the presence of a standardised amount of human IgM in an immunoglobulin preparation intended for feeding to newborns may bring an additional advantage because of the high opsonising and virus-neutralising activity of the antibodies of this isotype.

Comparison of early IgM-enriched immunoglobulin vs polyvalent IgG administration in score-identified postcardiac surgical patients at high risk for sepsis

STUDY OBJECTIVE

To address the relevance of the IgM component in polyvalent immunoglobulins in sepsis treatment by comparison of the clinical course under polyvalent IgG vs IgGMA therapy in postcardiac surgical patients at high risk for sepsis and to reassess the prognostic validity of sequential changes in acute physiology and chronic health evaluation (APACHE II) scores during treatment.

DESIGN

Prospective, randomized clinical trial.

SETTING

Cardiac surgical ICU in a university hospital.

PATIENTS

Among 870 consecutive patients after elective open-heart surgery, 29 (3.3%) met the previously validated high-risk criterion (APACHE II score > or = 24 on the first postoperative day) with a mean APACHE II score-predicted mortality risk of 63%.

INTERVENTIONS

In addition to standard therapy, 27 of these patients were randomized to receive commercially available IV IgG (Polyglobin N, n = 14, total dosage: 18 mL/kg) or IgGMA (Pentaglobin, n = 13, total dosage: 15 mL/kg).

MEASUREMENTS AND RESULTS

The two groups were comparable in baseline disease severity and concurrent therapy. The extent of score-quantified improvement in disease severity during treatment was similar in both groups (mean fall in APACHE II scores within 4 days; IgG, -6.9; IgGMA, -5.2), as were score-defined improvement rates (rate of patients with score decrease > or = 7 within 4 days: IgG, 57%; IgGMA, 54%) and in-hospital mortality (IgG, 29%; IgGMA, 31%) (all p = NS). There was a strong association between the decrease over time in APACHE II scores during therapy and prognosis (mortality rates in patients with vs without score-assessed improvement: 0% vs 67%, p = 0.0002).

CONCLUSIONS

IgG and IgGMA were associated with a comparable improvement in disease severity in score-identified postcardiac surgical patients at high risk for sepsis. Given the design as an efficacy rather than an equivalence study, this hypothesis derived from our results needs independent validation in larger trials. Sequential APACHE II score changes were reconfirmed as a prognostically valid quantitative measure of disease progress during sepsis therapy.

Oral IgA-IgG treatment of chronic non-specific diarrhoea in infants and children

The effect of orally administered immunoglobulin (IgAbulin) on chronic non-specific diarrhoea of infancy was studied in seven children, median age 26 (21-36) months and duration of diarrhoea 32 (18-84) weeks. Routine laboratory tests for malabsorption and small bowel biopsies were taken in all children before and after 3 weeks of IgAbulin treatment. The biopsy specimens were analysed with regard to histopathology, electronmicroscopy, immunohistochemistry and microbiology. The number of stools decreased from a median of 4.0 (3.0-5.0) to 1.5 (1.0 3.5) (p < 0.05) stools per day over the study period.

[Favorable effects of human immunoglobulin in severe forms of chronic inflammatory demyelinating polyneuropathy]

The authors present a case of a patient with serious type of chronic inflammatory demielinatig polyneuropathy treated successfully with human immunoglobulin Bioglobulin 0.2/kg body weight daily during 5 consecutive days.

Masking of the symptoms of esophageal and bowel perforation by combination treatment of sepsis with polyvalent immunoglobulins and low-dose hydrocortisone

Sepsis is usually treated with surgical drainage, antibiotics, oxygenation optimization and volume resuscitation. Recent monoclonal and polyclonal anti-bodies have been used to treat sepsis by neutralizing the endotoxins and cytokines found in septic patients. This method does not significantly reduce mortality except in certain sub-populations of the treatment groups. We introduced a combination approach for sepsis treatment. This adjuvant therapy consists of polyclonal human immunoglobins together with infusion of low-dose hydrocortisone. This paper reports the results of this treatment in two different cases.

[The therapy of gram-negative septicotoxic diseases with pentaglobin, an immunoglobulin with an elevated IgM content (a prospective, randomized clinical study)]

The aim of this study was to assess the efficacy of pentaglobin, a polyclonal polyvalent immunoglobulin containing IgG, IgM, and IgA, in therapy of septicotoxic diseases. Fifty-five patients with sepsis were divided into 2 perspective randomized groups. Group 1 (27 patients) were infused pentaglobin containing specific antibodies to bacterial endotoxin determinant. Immunoglobulin therapy was carried out during the first 3 days after the group was selected for study. In the other group (n = 28) no immunoglobulin therapy was carried out. During 6 weeks from the beginning of the study one patient out of 27 in group 1 (4%) died because of sepsis, whereas in group 2 nine patients died out of 28 (32%) (p < 0.01). A reliably higher titer of circulating endotoxins and a lower titer of antibodies to endotoxin determinant were revealed during the first 48 hours of experiment in the serum or plasma of patients who died in the course of the follow-up period, in comparison with the survivors.

Effect of treatment with nasal IgA on the incidence of infectious disease in world-class canoeists

Earlier studies of endurance athletes have shown decreased levels of secretory IgA and an increased frequency of upper respiratory tract (URT) infections after periods of hard training. In this study, 14 world-class canoeists were studied during very hard physical training, after lower-intensity training combined with 17 days of treatment with nasal IgA, and during low intensity training off-season. The ELISA method was used to determine IgA in nasopharyngeal (nph) secretions and saliva (s). The results demonstrated unchanged nph secretions before, during and after IgA treatment (IgAbulin, Immuno AG, Vienna, Austria). Saliva Ig-A increased significantly from a median value of 147 micrograms/ml (range 37-634) to 410 micrograms/ml (range 82-974) (p < 0.05) during treatment. Thereafter, s-IgA decreased to 244 micrograms/ml (range 85-689) off-season. A control group of untrained students showed similar nph IgA to that of the elite canoeists. The athletes receiving nasal IgA showed no signs of URT and were considered healthy during 14.5 days out of 17 days of treatment as compared to 12.3 healthy days out of 17 days in the control group. In summary there was no significant decrease in IgA in untreated elite canoeists as compared to untrained controls. Nasal IgA treatment increased the IgA level in saliva only, but no significant decrease in URT symptoms was seen during the IgA treatment period.

[Synergistic action of penicillin and immunoglobulin for intravenous (IVIG) use]

Combined effects of intravenous immunoglobulin and antibiotic in killing bacteria are of interest with extending clinical use of IGIV. Since the agents differ in antibacterial activity exerted by each of them, and their influence on the other, it is difficult to evaluate the combined effect in vitro. In our experiments the titer of antibody, and the killing of B Streptococcus type 090R, phagocytosis by chemiluminescence were examined in opsonic mixture. This mixture consist of IVIG, fresh serum, and neutrophils plus penicillin or without. The effect of combined IVIG and penicillin was higher than the effects of separate activities on bacteria. This observations suggest that the combination of IVIG and penicillin potentially useful in the treatment of GBS infection in some cases.

Induction of thrombosis in a mouse model by IgG, IgM and IgA immunoglobulins from patients with the antiphospholipid syndrome

Antiphospholipid syndrome is a disorder of recurrent thrombosis and pregnancy losses associated with production of anticardiolipin antibodies and lupus anticoagulant positivity. Recently, we have adapted a mouse model of induced venous thrombosis to study the role of autoantibodies in thrombus formation. To determine whether immunoglobulins from patients with the antiphospholipid syndrome play a role in thrombosis, we injected groups of CDI mice either with immunoglobulins purified from seven patients with the antiphospholipid syndrome (nine preparations studied: four IgG, three IgM and two IgA) or with immunoglobulins of the same isotype from healthy controls. Seventy-two h after injection, a non-occlusive thrombus was induced in the femoral veins of experimental mice by a pinch injury; the thrombus areas as well as times of formation and disappearance of the thrombi were measured. Eight of the nine antiphospholipid syndrome immunoglobulin preparations caused a significant increase in mean thrombus area and a significant delay in mean thrombus disappearance time as compared with normal controls. To determine whether anticardiolipin antibodies might be involved, separate groups of mice were injected with affinity-purified IgG (n = 2) or IgM (n = 2) anticardiolipin antibodies or with normal immunoglobulins of the same isotype, and the effects on thrombus formation compared. Mean thrombus area and mean disappearance times were again significantly increased in all four groups injected with affinity-purified antibodies. This is the first study to show that anticardiolipin antibodies of IgG, IgM and IgA isotypes may play a role in thrombosis in vivo.

Monoclonal immunoglobulin A antibody directed against serotype-specific epitope of Shigella flexneri lipopolysaccharide protects against murine experimental shigellosis

To determine the role of humoral mucosal immune response in protection against shigellosis, we have obtained a monoclonal dimeric immunoglobulin A (IgA) antibody specific for Shigella flexneri serotype 5a lipopolysaccharide (mIgA) and used a murine pulmonary infection model that mimics the lesions occurring in natural intestinal infection. Adult BALB/c mice challenged with 10(7) S. flexneri organisms developed a rapid inflammatory response characterized by polymorphonuclear cell infiltration around and within the bronchi and strong systemic interleukin 6 response. Implantation of hybridoma cells in the back of mice, resulting in the development of a myeloma tumor producing mIgA in the serum and subsequently secretory mIgA in local secretions, or direct intranasal administration of these antibodies, protected the animals against subsequent intranasal challenge with S. flexneri serotype 5a. Absence of histopathological lesion and significant decrease in bacterial load of the lungs and of systemic interleukin 6 response were the three major criteria of protection. This protection was shown to be serotype-specific and dependent on local concentration of mIgA. These data demonstrate that mucosal antibodies directed against a single polysaccharidic surface epitope of Shigella can protect against the disease.

A protective role for lymphocytes in cyclophosphamide-induced endogenous bacteraemia in mice

Cyclophosphamide (CY) is used in many animal studies, including models of bacteraemia, to deplete peripheral neutrophils and induce a compromised state. Although CY also influences lymphocyte function, the protective role of lymphocytes in bacteraemia is unclear. Therefore, CY (200 mg/kg) was administered to ddY mice and its influence on the number, cellular composition, and function of lymphocytes in the spleen and Peyer's patches was examined. A single dose of CY reduced the number of lymphocytes in a time-dependent fashion. Flow cytometry showed that B cells carrying B220 antigen decreased significantly. The production of IgA in Peyer's patches, as measured by enzyme-linked immunosorbent assay, was also suppressed in a time-dependent fashion. Blastogenic responses of splenic lymphocytes to Concanavalin-A, lipopolysaccharide and heat-killed Pseudomonas aeruginosa were suppressed 48 h after CY administration. The results suggest that CY suppresses the number and function of lymphocytes, especially B cells. This may lead to bacterial overgrowth in the gut and result in bacteraemia. Intravenous transfusion of normal lymphocytes or oral inoculation of IgA to mice with P. aeruginosa D4 endogenous bacteraemia significantly increased survival rates, indicating that lymphocytes and their products have a protective role in bacteraemia in mice.

Vaccine strategies for prevention of Helicobacter pylori infection

OBJECTIVE

To examine the level and duration of the humoral immune response to Helicobacter felis following oral immunization or infection.

DESIGN AND METHODS

Germ-free mice were orally immunized with sonicated H. felis plus cholera toxin five times over 6 weeks. One week after immunization was completed, immunized and control non-immunized mice received an oral challenge of live H. felis organisms. The animals were killed at 3-week intervals and serum, gastric washings, intestinal washings and gastric biopsies were obtained. H. felis infection was confirmed by a positive urease test or culture of the gastric biopsy. Serum gastric and intestinal antibody titers were determined by enzyme-linked immunosorbent assay.

CONCLUSION

Infection and immunization against H. felis produces a specific humoral response. The humoral response in infection alone is significantly smaller than that of immunized animals until 6 weeks after infection. The humoral response following oral immunization persists for at least 18 weeks without further stimulation. The presence of an H. felis-specific antibody immune response before infection may be needed to protect animals from acute Helicobacter infection.