Post-therapeutic cure criterion in chronic Chagas disease using Trypanosoma cruzi chimeric proteins

Chagas disease (CD) is a neglected disease caused by Trypanosoma cruzi Chagas, 1909. Causative treatment can be achieved with two drugs: benznidazole or Nifurtimox. There are some gaps that hinder progress in eradicating the disease. There is no test that can efficiently assess cure control after treatment. Currently, the decline in anti-T. cruzi antibody titres is assessed with conventional serological tests, which can take years. However, the search for new markers of cure must continue to fill this gap. The present study aimed to evaluate the decline in serological titres using chimeric proteins after treatment with benznidazole in chronic patients diagnosed with CD. It was a prospective cross-sectional cohort study between 2000 and 2004 of T. cruzi-positive participants from the Añatuya region (Argentina) treated with benznidazole. Serum samples from ten patients were collected before treatment (day zero) and after the end of treatment (2, 3, 6, 12, 24 and 36 months). For the detection of anti-T. cruzi antibodies, an indirect ELISA was performed using two chimeric recombinant proteins (IBMP-8.1 and IBMP-8.4) as antigens. The changes in reactivity index within the groups before and after treatment were evaluated using the Friedman test. All participants experienced a decrease in serological titres after treatment with benznidazole, especially IBMP-8.1. However, due to the small number of samples and the short follow-up period, it is premature to conclude that this molecule serves as a criterion for sustained cure. Further studies are needed to validate tests based on these or other biomarkers to demonstrate parasitological cure.

Does decreasing the incubation period used in the antibody screen affect its sensitivity?

BACKGROUND

Pre-transfusion testing (PTT) encompasses a set of mandatory laboratory tests performed before red blood cell transfusion. The antibody screen, one component of PTT, commonly includes a 10-20 min incubation. The primary aim of this study was to determine if this period can be reduced when using current immunohematology methodologies.

METHODS AND MATERIALS

Antibody screens were performed on reagent samples using Glass or Gel-based column agglutination technologies (CAT) and a solid phase red cell adherence (SPRCA) assay, with incubation periods of 1, 5, 10 and 15 min, and 20 min (SPRCA assay only). For each method, the shortest period producing a minimum of a 1+ reaction with all reagent samples was considered optimal. The sensitivity of each assay using the optimal period was calculated after performing antibody screens on 100 patient samples.

RESULTS AND DISCUSSION

It was demonstrated that the incubation period in the SPRCA and Glass CAT systems can be reduced to 5 and 10 min, respectively, while achieving high assay sensitivity (98.9% in both). The incubation period in the Gel CAT system cannot be reduced from 15 min. Significant association between titre and reaction strength was observed for all three screening methods (p < 0.001 for both CAT methods, p = 0.041 for SPRCA). This study demonstrates that the incubation period used in the antibody screen can be reduced when using systems employing the Glass CAT and SPRCA methods, without affecting assay sensitivity. If confirmed, it could result in faster completion of PTT.

Chlamydia trachomatis seropositivity among women with tubal factor infertility and fertile controls: a comparative study

Introduction

Chlamydia trachomatis is the most reported bacterial sexually transmitted infection and if not properly treated may lead to tubal blockage. Tubal factor infertility is the most common form of infertility in Nigeria. This study was designed to determine the usefulness of chlamydia antibody testing in diagnosis of tubal factor infertility.

Methods

this was a comparative cross-sectional study conducted in Olabisi Onabanjo University Teaching Hospital Sagamu. One hundred and forty-seven women with tubal blockage on hysterosalpingography and confirmed with laparoscopy, and pregnant control were recruited using convenience sampling method. Information obtained and chlamydia assay results were entered into a computer and analyzed using SPSS version 21. Chi-square was used to determine association between categorical variables. Logistic regression analysis was used to determine the risk factors associated with chlamydia infection.

Results

ninety-four (63.9%) of the women with tubal factor infertility were positive for chlamydia IgG antibodies while 37(25.2%) women in the control group had positive results for IgG antibody. This was statistically significant (P=0.001). Analysis using multivariate logistic regression shows early age of coitarche, presence of multiple sexual partners and previous sexually transmitted infection were significantly associated with chlamydia infection (P=0.001).

Conclusion

there was a strong association between chlamydia seropositivity and tubal blockage. Early age at coitarche, previous sexually transmitted infection and multiple sexual partners are significant risk factors for chlamydial infection. Chlamydia trachomatis antibody testing could be used as marker for tubal blockage when evaluating infertile patient.

SARS-CoV-2 and Influenza Vaccines in People with Excessive Body Mass-A Narrative Review

In the face of a growing number of overweight people and two widely known viral diseases, SARS-CoV-2 and influenza, it is crucial to be aware of the impact of excess body weight on immunisation against these diseases. The aim of this review is to show the effectiveness of SARS-CoV-2 and influenza vaccines in overweight and obese patients. Excessive adipose tissue releases cytokines and maintains local hypoxia, which causes persistent low-grade inflammation. These factors make excess body mass patients' immune systems weaker. Under such conditions, the humoral response becomes less efficient, leading to a weakened ability to fight against infection and an increased risk of developing lower antibody titres. Vaccines help to reduce morbidity both in normal-weight and excess body mass people, although most studies show that patients with higher BMI tend to lose the antibodies produced more quickly. It is shown that the most effective vaccines (in terms of preventing the infection and potential post-illness complications) are the BNT162b2 vaccine against SARS-CoV-2 and the inactivated influenza vaccine against influenza among both obese and non-obese subjects.

The spectrum of ABO haemolytic disease of the fetus and newborn in neonates born to group O mothers

BACKGROUND AND OBJECTIVES

ABO haemolytic disease of the fetus and newborn (HDFN) is a lesser recognized entity; however, the severity may vary in neonates. This prospective observational study was performed to determine the severity and risk of ABO-HDFN in neonates born to O group mothers.

MATERIALS AND METHODS

A total of 260 neonates born to non-alloimmunized blood group O mothers were recruited. Blood group O neonates were excluded from the study. Neonatal direct antiglobulin test (DAT) was performed using the column agglutination technique. They were monitored for clinical and laboratory parameters and followed up at 6-8 weeks. The maternal anti-A and anti-B titres (IgM and IgG) were also done.

RESULTS

A total of 176 neonates with blood group A (77/260; 29.6%) and B (99/260; 38.1%) were finally included in the study, and 15 (8.5%) of them were DAT positive. Overall, 26.7% (47/176) neonates received phototherapy, 172 (97.7%) survived and none required readmission. The median (inter-quartile range [IQR]) maternal IgG anti-B titre (32 [32-64]) was significantly higher (p < 0.001) than the IgG anti-A titre (16 [8-64]). The maximum total serum bilirubin in neonates had a significant positive association with neonatal birth weight (p = 0.045), positive DAT (p = 0.006) and requirement of phototherapy (p < 0.001). The relative risk (95% CI) of a DAT-positive neonate requiring phototherapy was 4.55 (3.12-6.33).

CONCLUSION

The frequency of ABO incompatibility in neonates born to group O mothers was 67.69% (176/260). The maternal IgG titre of ≥64 could be a good predictor for identifying the neonates at risk of developing hyperbilirubinaemia requiring phototherapy.

Clinical predictors of donor antibody titre and correlation with recipient antibody response in a COVID-19 convalescent plasma clinical trial

BACKGROUND

Convalescent plasma therapy for COVID-19 relies on transfer of anti-viral antibody from donors to recipients via plasma transfusion. The relationship between clinical characteristics and antibody response to COVID-19 is not well defined. We investigated predictors of convalescent antibody production and quantified recipient antibody response in a convalescent plasma therapy clinical trial.

METHODS

Multivariable analysis of clinical and serological parameters in 103 confirmed COVID-19 convalescent plasma donors 28 days or more following symptom resolution was performed. Mixed-effects regression models with piecewise linear trends were used to characterize serial antibody responses in 10 convalescent plasma recipients with severe COVID-19.

RESULTS

Donor antibody titres ranged from 0 to 1 : 3892 (anti-receptor binding domain (RBD)) and 0 to 1 : 3289 (anti-spike). Higher anti-RBD and anti-spike titres were associated with increased age, hospitalization for COVID-19, fever and absence of myalgia (all P < 0.05). Fatigue was significantly associated with anti-RBD (P = 0.03). In pairwise comparison amongst ABO blood types, AB donors had higher anti-RBD and anti-spike than O donors (P < 0.05). No toxicity was associated with plasma transfusion. Non-ECMO recipient anti-RBD antibody titre increased on average 31% per day during the first three days post-transfusion (P = 0.01) and anti-spike antibody titre by 40.3% (P = 0.02).

CONCLUSION

Advanced age, fever, absence of myalgia, fatigue, blood type and hospitalization were associated with higher convalescent antibody titre to COVID-19. Despite variability in donor titre, 80% of convalescent plasma recipients showed significant increase in antibody levels post-transfusion. A more complete understanding of the dose-response effect of plasma transfusion amongst COVID-19-infected patients is needed.

Equine leptospirosis: Experimental challenge of Leptospira interrogans serovar Bratislava fails to establish infection in naïve horses

BACKGROUND

Little information is available about experimental inoculation of leptospirosis in horses and the pathogenicity of Leptospira interrogans serovar Bratislava in this host.

OBJECTIVES

To determine the serological, clinical, pathological and haematological responses of horses to L. interrogans serovar Bratislava strain PigK151.

STUDY DESIGN

Randomised controlled in vivo experiment.

METHODS

Ten seronegative female foals were divided into 2 groups, control (n = 4) and challenged (n = 6). The challenged group received 1 × 10⁹ leptospires divided equally between topical ocular and intraperitoneal injections. Blood and urine samples were analysed. The temperature was recorded daily for the first 9 days, then weekly. Sera were tested by microscopic agglutination test (MAT). Automated complete blood count, differential and chemistry panel were performed. Histopathological analysis was performed on sections of liver, kidney, urinary bladder, uterine body and pineal gland. Sample culturing was performed from blood, urine, liver, kidney, reproductive tract and vitreous humour.

RESULTS

No pyrexia was noted. PCR and culture were negative from all samples. Differences between groups were found in CBC, differential counts and serum biochemistry panel (or profile), suggesting that leptospiral challenge triggered an inflammatory response. No evidence of leptospirosis was found from histopathological analysis. All challenged foals developed a humoral response. The MAT allowed the confirmation of the infecting serovar at a later stage, but it also revealed cross-reactive results that were further explained by genomic analysis.

MAIN LIMITATIONS

This experimental challenge had two main limitations: (a) the results might have varied if another strain from the same serovar had been used and (b) the use of another route of infection and a higher bacterial dose might have achieved colonisation.

CONCLUSIONS

Based on these findings, it may suggest that L. interrogans serovar Bratislava is neither pathogenic nor host-adapted serovar for horses, although these results might have varied if another strain from the same serovar had been used instead.

Hepatitis B surface antibody titres and hepatitis B reactivation with direct-acting antiviral therapy for hepatitis C

HBV reactivation can occur while undergoing direct-acting antiviral (DAA) therapy for hepatitis C virus (HCV). The role of hepatitis B surface antibody (HBsAb) has not been systematically explored. Therefore, the purpose of this systematic review was to explore the role of the presence of HBsAb on the risk of HBV reactivation related to DAA therapy. We reviewed MEDLINE, CINAHL, EMBASE and Cochrane Central for studies on DAA therapy and data on HBsAb in patients with resolved hepatitis B (hepatitis B surface antigen-negative and hepatitis B core antibody-positive). We identified twenty-nine reports: thirteen case reports with HBV reactivation (10 HBsAb-negative and 3 HBsAb-positive patients) and sixteen cohort studies totalling 2528 patients with resolved HBV infection (1429 HBsAb negative, 1099 HBsAb positive). Reactivation was found in 12 (0.8%) HBsAb-negative and 7 (0.6%) HBsAb-positive individuals of cohort studies. All but two HBV reactivation occurred in patients with HBsAb titre <30 iU/L. The presence of HBsAb showed a trend towards delayed reactivation (median 12 weeks vs 9.5 weeks; P = .07). Importantly, with the exception of a patient with escape variant and an HIV-infected individual, no HBsAb-positive individual demonstrated clinical reactivation. HBsAb presence seems to protect from clinical HBV reactivation related to DAA therapy. The most pronounced prevention for reactivation may require titres greater than 30 iU/L.

Changes in the Percentages of B- and T-Lymphocytes and Antibody Titres in Laying Hens Infested with Dermanyssus gallinae-A Preliminary Study

(1) Background: Dermanyssus gallinae, a hematophagous ectoparasite, adversely affects the health status of laying hens, leading to reduced egg production and significant economic losses in commercial farms. The aim of this study was to determine the effect of D. gallinae on the development of post-vaccination immune responses in layer hens. (2) Methods: A total of 80 blood samples were collected at four time-points (B1-B4) from 10 Hy-Line Brown hens, randomly selected from a commercial layer farm. The flock was naturally infested with D. gallinae and treated twice with Biobeck PA 910 (AI silicon dioxide). The samples were collected before and after each treatment. The percentages of IgM+ B cells, CD3+/CD4+ T cells and CD3+/CD8a+ T cells were determined by flow cytometry; the titres of antibodies against avian encephalomyelitis, infectious bronchitis virus, Newcastle disease virus, Ornithobacterium rhinotracheale, reticuloendotheliosis virus and avian reovirus were determined by the immunoenzymatic method. (3) Results: The percentage of Th cells and post-vaccination anti-IBV and anti-NDV antibodies decreased significantly at the second infestation peak when the number of parasites was twice higher than at the first infestation peak. Non-significant negative correlations were found between the number of mites and the percentage of B cells (R = -0.845, p > 0.05) and between the number of mites and the percentage of Th cells (R = -0.522, p > 0.05), and a significant positive correlation was noted between the number of mites and the percentage of Tc cells (R = -0.982, p < 0.05). There were non-significant correlations between the number of mites and antibody titres. (4) Conclusion: The present findings suggested that D. gallinae might inhibit immune responses since the percentages of B cells and Th cells were negatively correlated with the number of mites. The percentage of Tc cells was positively correlated with the number of mites, which indicated that D. gallinae could stimulate cellular immune responses in infested laying hens. However, further research is needed to determine whether D. gallinae suppresses the production of vaccine-induced antibodies.

Factors associated with the activity and severity of bullous pemphigoid: a review

Bullous pemphigoid (BP) is the most common subepidermal autoimmune blistering disease. It usually affects people older than 70 years of age. The two main autoantigens are BP180 and BP230, both of which are components of hemidesmosomes. Immunoglobulin (Ig)G and IgE autoantibodies to BP180 detected by the enzyme-linked immunoassay (ELISA) show close associations with the activity and severity of BP. In addition, inflammatory cells (eosinophils, neutrophils and mast cells) and cytokines (e.g. interleukins and CC chemokine ligands) play an important part in the pathogenesis, activity and severity of BP. We summarized the potential contribution of each factor postulated to be associated with the activity and severity of BP, and provide guidance for clinicians to pay timely and close attention to such parameters. This review may also promote the development of novel therapies for BP.Key MessagesBullous Pemphigoid Disease Area Index (BPDAI) is a scoring system which can reflect the extent of clinical involvement of BP patients.The titres of IgE autoantibodies and IgG autoantibodies against the NC16A domain of BP180 are closely correlated with the activity and severity of BP.Many inflammatory cells and molecules, such as eosinophils and interleukins, can also reflect the activity and severity of BP.

Monitoring of prenatal patients using a combined antibody titre for Rh and non-Rh antibodies

OBJECTIVES

This was a laboratory exercise designed to determine whether combined antibody titrations in the presence of multiple antibodies achieve a critical level earlier or at the same time as antibodies having individual antibody titrations.

BACKGROUND

Management of haemolytic disease of the fetus and newborn involves monitoring maternal antibody concentration by antibody titration. Separate titrations are generally performed for each antibody.

METHOD

Thirty-one samples containing combinations of two different Rh and/or non-Rh antibodies were examined with separate titres for each antibody and one single combined titration.

RESULTS

Of 31 samples, 19 (61.3%) showed an increased combined titre. Of 12 samples that showed no increase, 10 contained a separate titre of <1 for either one or both antibodies. Where both antibodies had a separate titre of ≥1, 15 of 17 (88.2%) showed an increased combined titre. In contrast to the separate titration method, no decrease in titre level was observed using the combined method.

CONCLUSION

Where two antibodies are present, titrations performed by a combined method will produce titre levels equal to or higher than antibodies titred individually. Therefore, a combined titration can be expected to reach a critical titre level as early as, or earlier in gestation than, antibodies monitored by a single titration method. Further studies relating fetal outcomes to titration methodology would be valuable in determining the validity of this approach for prenatal management. Cost-effectiveness of this approach to prenatal screening should also be assessed.

Antibody response to Influenza booster vaccination in Franches-Montagnes stallions supplemented with Equi-Strath® : a randomized trial

Bio-Strath® is a plasmolyzed yeast product enriched with herbs, malt, honey and orange juice. In this study, the effect of Equi-Strath® , the adapted product for horses, on the equine immune system was evaluated. A routine influenza booster vaccination was used as a model to study the effects of Equi-Strath® supplementation on the immune response. Twenty healthy Franches-Montagnes stallions with pre-existing antibody levels were randomly divided into a study group (SG, n = 10) receiving 0.06 mL/kg bodyweight of Equi-Strath® , and a control group (CG, n = 10), receiving the same amount of placebo, daily. The supplement and placebo were given from week 1 until week 14 of the trial. After 10 weeks, the horses were vaccinated with a commercial vaccine containing equine influenza strains of the H3N8 subtype. Antibody titres in blood were measured at day 0 before vaccination, and 14 and 32 days after vaccination. In addition, a complete blood count (CBC) was performed on day 0 and day 32. A linear increase of haemagglutination inhibition titres in both groups was observed after vaccination, but with no difference between treatment groups. CBC components remained unaffected by treatment. In conclusion, daily Equi-Strath® supplementation did not affect the adaptive immune response in stallions after a routine commercial H3N8 influenza booster vaccination.

The role of Leptospira spp. in horses affected with recurrent uveitis in the UK

BACKGROUND

Equine recurrent uveitis (ERU) is a common cause of ocular pain and blindness in horses. Leptospira spp. have been commonly implicated in the pathophysiology of ERU in mainland Europe and the USA. No recent studies have been carried out in the UK, but Leptospira is reported not to be a major factor in the aetiology of ERU in the UK.

OBJECTIVES

To establish the prevalence of Leptospira-associated ERU in the UK and to identify the serovars involved in these cases; to compare serum vs. aqueous humour antibody levels in cases and controls in order to confirm the diagnosis of Leptospira-associated ERU, and to assess the usefulness of serology alone as a confirmatory test for Leptospira-associated ERU in the UK.

STUDY DESIGN

Case-control study.

METHODS

Eyes enucleated for clinical reasons in ERU-affected horses were collected. Blood and aqueous humour were obtained to determine antibody levels against a variety of Leptospira serovars and C-values (aqueous humour value/serum value) were calculated. In addition, eyes, blood and aqueous humour were obtained from control cases for comparison. Histopathology was performed in all eyes to confirm uveitis in each case. Differences in seroprevalences between ERU and control cases and between Leptospira- and non-Leptospira-associated ERU cases were calculated.

RESULTS

A total of 30 ERU and 43 control eyes were analysed. Of the ERU eyes, only two had a C-value of >4 (prevalence of Leptospira-associated uveitis: 6.7%). Serovars hardjo and javanica were detected. There was no difference in seroprevalence between horses with uveitis and control cases (65.5% and 41.9%, respectively; P = 0.11) or between Leptospira- and non-Leptospira-associated uveitis cases (100% and 63.0%, respectively; P = 0.52).

MAIN LIMITATIONS

The study was limited by low case numbers. Eyes were presented at different stages of disease. The only test used to detect Leptospira was the microscopic agglutination test.

CONCLUSIONS

Leptospira-associated ERU is uncommon in the UK. Serology alone may not help to definitively diagnose Leptospira-associated uveitis in this country.

Effect of arginine or glutamine supplementation on production, organ weights, interferon gamma, interleukin 6 and antibody titre of broilers

The objective of this study was designed to test whether supplementation of the diet with arginine (Arg) or glutamine (Gln) or their combination influences the production, organ weights and humoral immune response of broilers. A total of 432 one-day-old male Ross 308 broiler chickens were divided into 6 treatment groups: control, Arg-0.5%, Arg-1%, Gln-0.5%, Gln-1% and Arg-0.5%+Gln-0.5%. Drinking water and feed were provided ad libitum. On day 18 of the experiment 50% of chickens in each treatment group were immunised with bovine serum albumin. Ten and 21 days after immunisation blood samples were collected to determine the anti-albumin IgY titre, interleukin 6 (IL6) and interferon gamma (IFNG) and to measure the weight of the liver, spleen, bursa of Fabricius and thymus. Arg or Gln supplementation of the diets influenced neither the production nor the organ weights until 18 days of age. Between 18 and 39 days of age both Arg (0.5% and 1%) and Arg + Gln supplementation improved the feed conversion ratio (FCR) by 3.7%, 6.3% and 4.9%, respectively, while Gln-1% worsened it by 15%. Immunisation slightly (-0.79%) depressed the body weight gain of broilers fed the control diet, which was significantly improved by both Arg (0.5 or 1%) and Arg + Gln supplementation. Immunisation increased the weight of the spleen, bursa and thymus and decreased that of the liver. Supplementation with 1% Gln depressed (-5.13%) the body weight gain of the immunised chickens but strongly stimulated the immune response. Supplementations with Arg and Gln did not influence the IL6 and IFNG level of the blood; however, on day 10 after immunisation these two parameters showed a negative correlation with each other. Regarding production, organ weights and immunity, Arg supplementation should be recommended in the grower phase, while Gln supplementation can be useful in pullets raised for egg production, where a good immune response to vaccinations is an important factor.

Prevalence and titre of antibodies to cytomegalovirus and epstein-barr virus in patients with autism spectrum disorder

BACKGROUND/AIM

The etiology of autism spectrum disorders (ASD) is currently unknown. Few studies have explored the role of Cytomegalovirus (CMV) and Epstein Barr Virus (EBV) as potential etiological factors of ASD. The aim of the present study was to evaluate the seropositivity rate and antibody titre to CMV and EBV in children with ASD compared to same-aged healthy controls.

PATIENTS AND METHODS

We compared the seropositivity rate and titre of antibodies to CMV and EBV in 54 children with ASD (19 with autistic disorder and 35 with non-autistic disorder ASD) and in 46 controls.

RESULTS

Seropositivity rate and titre of the two antibodies were not dissimilar between cases and controls. However, considering only patients with ASD, those seropositive for CMV tended to test worse to the major severity scales than the seronegative ones.

CONCLUSION

Titre and seropositivity rate of antibodies to CMV and EBV are similar between children with ASD and healthy controls.

Seasonal changes in the antibody responses against Plasmodium falciparum merozoite surface antigens in areas of differing malaria endemicity in Indonesia

BACKGROUND

The transmission of malaria in Indonesia is highly heterogeneous spatially and seasonally. Anti-malaria antibody responses can help characterize this variation. In the present study antibody responses to Plasmodium falciparum MSP-1 and AMA-1 were measured to assess the transmission intensity in a hypo-endemic area of Purworejo and a meso-endemic area of Lampung during low and high transmission seasons.

METHODS

Filter-paper blood spot samples collected from Purworejo and Lampung by cross-sectional survey during high and low transmission season were stored at -20°C. Indirect ELISA assays were carried out using PfMSP1-19 and PfAMA1 antigens. A positivity threshold was determined by samples from local unexposed individuals, and the differences in seroprevalence, antibody level and correlation between antibody level and age in each site were statistically analysed.

RESULTS

Prevalence of antibodies to either PfMSP1-19 or PfAMA1 was higher in Lampung than in Purworejo in both the low (51.3 vs 25.0%) and high transmission season (53.9 vs 37.5%). The magnitude of antibody responses was associated with increasing age in both sites and was higher in Lampung. Age-adjusted seroconversion rates showed an approximately ten-fold difference between Lampung and Purowejo. Two different seroconversion rates were estimated for Lampung suggesting behaviour-related differences in exposure. In both settings antibody responses to PfMSP1-19 were significantly lower in the low season compared to the high season.

CONCLUSION

Seasonal changes may be detectable by changes in antibody responses. This is particularly apparent in lower transmission settings and with less immunogenic antigens (in this case PfMSP1-19). Examination of antibody levels rather than seroprevalence is likely to be a more sensitive indicator of changes in transmission. These data suggest that sero-epidemiological analysis may have a role in assessing short-term changes in exposure especially in low or seasonal transmission settings.

Proper quality control of formulated foot-and-mouth disease vaccines in countries with prophylactic vaccination is necessary

Vaccination is considered as an important tool to control foot-and-mouth disease (FMD). A good quality vaccine containing relevant serotypes and matching strains is a pre-requisite for vaccination to be effective. The present study investigated the quality of different brands of FMD vaccine available in Pakistan, including three locally produced and two imported products. All the vaccines were found free of bacterial or fungal contamination. No adverse effects were noted in suckling mice and buffalo calves inoculated with the vaccines, showing that the vaccines were sterile and safe. The humoral immune response to the FMD vaccines was determined in buffalo calves for 234 days post-vaccination. Very low humoral immune responses against FMD serotypes O, A and Asia 1 viruses were detected to the locally produced vaccines. The imported vaccines, however, elicited a higher antibody response which persisted for a long period in one of the 2 vaccines. The present study highlights the need of assessing an independent vaccine quality control of finished FMD vaccine products.

Evaluation of Helicobacter pylori infection in patients with common migraine headache

INTRODUCTION

Migraine can cause headache in different communities so that 12-15% are suffering worldwide. Recently the relationship between infectious diseases such as Helicobacter pylori infection and migraine headache has been the focus of many studies. The current study was designed to evaluate IgG and IgM antibodies to H. pylori in patients suffering from migraine headaches.

MATERIAL AND METHODS

Patients who had diagnostic criteria for migraine were chosen as cases compared to some healthy individuals as the control group amongst which immunoglobulin G (IgG), immunoglobulin M (IgM), age, job, gastro-intestinal (GI) disorders, history of migraine, special meals, medications, sleeping disorders, stress, environmental factors etc were analysed.

RESULTS

The prevalence of disease was 38.6%. Household women had the highest prevalence (40%). Among them menstruation was related to high prevalence of migraine. 75.6% of patients had gastrointestinal disorders of which the gastric reflux was the most important sign (47.1%). The mean optical density (OD) value of IgG and IgM antibody to H. pylori was 60.08 ±7.7 and 32.1 ±8.7 for the case group, 21.82 ±6.2 and 17.6 ±9.4 for the control group, respectively.

CONCLUSIONS

There was a significant difference in mean OD value of both antibodies to H. pylori amongst the case and control groups. As a result, active H. pylori infection is strongly related to the outbreak and severity of migraine headaches, and H. pylori treatment reduces migraine headaches significantly. Hopefully, the definite treatment and eradication of this infection can cure or reduce the severity and course of migraine headaches significantly if not totally.

Differential maturation of avidity of IgG antibodies to gp41, p24 and p17 following infection with HIV-1

We have evaluated solid-phase ELISA IgG antibody avidity studies as a means of identifying cases of recent HIV-1 infection. Although separate studies on the avidity of anti-gp41 and anti-p24 antibodies in seroconvertors have been reported, a comparison of the ability of patients to simultaneously mature their immune response to more than one HIV antigen immediately following seroconversion appears to be lacking. We have demonstrated a maturation in anti-gp41 avidity which reflects the time since seroconversion in all cases. In contrast, however, only some patients produced high-avidity anti-p24 or anti-p17 antibodies during the same time span. While the avidity of anti-gp41 antibodies remained high in cases of non-recent HIV infection, even in the face of advanced disease, we have confirmed the findings of others that the avidity of anti-p24 falls before the onset of ARC or AIDS. Therefore, whilst the avidity of anti-gp41 antibodies could reliably be of value in identifying cases of recent HIV infection, the avidity of anti-p24 or anti-p17 antibodies could not, but may be of prognostic value, even at an early stage. The time taken to reach maximum anti-p17, anti-p24 and anti-gp41 titres was variable, but anti-gp41 titres, like anti-gp41 avidity, remained high. In contrast, anti-p24 titres fell, even during the early followup period in some seroconvertors. Anti-p24 antibody avidity, however, appeared to be a better predictor of disease progression in 'remote' cases than anti-p24 titre. The avidity and titres of these antibodies are presented in relation to the clinical details, p24 antigen status, CD4 and CD8 counts where these are known.

Immunity following intranasal administration of an inactivated, freeze-dried A/England/42/72 vaccine

A group of 23 student volunteers were each inoculated intranasally with 400 IU of inactivated, freeze-dried A/England/42/72 vaccine. Only one volunteer showed a four-fold rise in serum HI antibody following immunization, and the mean increase in serum HI antibody (gmt) for all volunteers did not increase two-fold. Thirteen of the volunteers developed detectable levels of nasal wash neutralizing antibody after immunization; local antibody was most commonly found in volunteers who produced a detectable but less than four-fold fise in serum antibody titre, and who produced nasal washings with relatively high concentrations of protein and secretory IgA. Four weeks after immunization, the vaccinees and a matched group of control subjects were inoculated with attenuated A/England/42/72 (MRC-7) virus. Evidence of infection was found in 14 of 23 (61 per cent) of control subjects and in seven of 23 (30 per cent) of immunized volunteers. This result showed a significant protection (P = 0.04) against challenge virus infection for volunteers given intranasal vaccine.

The effect of prior inoculation with an enterovirus (LEV 4) on rhinovirus infection of volunteers

Twenty-four volunteers at the Common Cold Unit were divided into two groups of twelve. One group was vaccinated orally with an enterovirus (LEV 4) and the other with nutrient broth. Both groups were challenged three days later with intranasal rhinovirus 4 and they were observed clinically and monitored by laboratory tests to see if any modification of the rhinovirus infection occurred.

All the vaccinated volunteers were successfully infected with LEV 4 and were excreting the enterovirus in the faeces at near maximum titres at the time of the rhinovirus infection, following which 67 per cent of the volunteers were infected and 29 per cent developed symptoms. However, the vaccinated group did not differ from the unvaccinated in respect of the illness induced, the excretion of rhinovirus type 4 or the rise of RV 4 antibody titre. LEV 4 was isolated from the nasopharynx of some of the volunteers, but the rhinovirus infection was not modified even in these. Interferon was present in the serum and nasal washings of nine volunteers in all, of whom only 3 had received the LEV 4 vaccination.

Two additional volunteers were shown to be insusceptible to reinfection with LEV4. It was concluded that live enterovirus vaccination does not induce viral interference.