Prozone masks elevated SARS-CoV-2 antibody level measurements

We report a prozone effect in measurement of SARS-CoV-2 spike protein antibody levels from an antibody surveillance program. Briefly, the prozone effect occurs in immunoassays when excessively high antibody concentration disrupts the immune complex formation, resulting in a spuriously low reported result. Following participant inquiries, we observed anomalously low measurement of SARS-CoV-2 spike protein antibody levels using the Roche Elecsys® Anti-SARS-CoV-2 S immunoassay from participants in the Texas Coronavirus Antibody Research survey (Texas CARES), an ongoing prospective, longitudinal antibody surveillance program. In July, 2022, samples were collected from ten participants with anomalously low results for serial dilution studies, and a prozone effect was confirmed. From October, 2022 to March, 2023, serial dilution of samples detected 74 additional cases of prozone out of 1,720 participants' samples. Prozone effect may affect clinical management of at-risk populations repeatedly exposed to SARS-CoV-2 spike protein through multiple immunizations or serial infections, making awareness and mitigation of this issue paramount.

Social determinants of health predict readmission following COVID-19 hospitalization: a health information exchange-based retrospective cohort study

Introduction

Since February 2020, over 104 million people in the United States have been diagnosed with SARS-CoV-2 infection, or COVID-19, with over 8.5 million reported in the state of Texas. This study analyzed social determinants of health as predictors for readmission among COVID-19 patients in Southeast Texas, United States.

Methods

A retrospective cohort study was conducted investigating demographic and clinical risk factors for 30, 60, and 90-day readmission outcomes among adult patients with a COVID-19-associated inpatient hospitalization encounter within a regional health information exchange between February 1, 2020, to December 1, 2022.

Results and discussion

In this cohort of 91,007 adult patients with a COVID-19-associated hospitalization, over 21% were readmitted to the hospital within 90  days (n = 19,679), and 13% were readmitted within 30  days (n = 11,912). In logistic regression analyses, Hispanic and non-Hispanic Asian patients were less likely to be readmitted within 90  days (adjusted odds ratio [aOR]: 0.8, 95% confidence interval [CI]: 0.7-0.9, and aOR: 0.8, 95% CI: 0.8-0.8), while non-Hispanic Black patients were more likely to be readmitted (aOR: 1.1, 95% CI: 1.0-1.1, p = 0.002), compared to non-Hispanic White patients. Area deprivation index displayed a clear dose-response relationship to readmission: patients living in the most disadvantaged neighborhoods were more likely to be readmitted within 30 (aOR: 1.1, 95% CI: 1.0-1.2), 60 (aOR: 1.1, 95% CI: 1.2-1.2), and 90  days (aOR: 1.2, 95% CI: 1.1-1.2), compared to patients from the least disadvantaged neighborhoods. Our findings demonstrate the lasting impact of COVID-19, especially among members of marginalized communities, and the increasing burden of COVID-19 morbidity on the healthcare system.

Antigen specificity of serum antibody in A. actinomycetemcomitans-infected periodontitis patients

We hypothesized that serum antibody with selected antigen specificities would relate to infection and disease in the patients and, thus, describe the characteristics of potential protective antibody. This study used serum samples from 24 periodontitis patients with subgingival infection and elevated serum IgG antibody to A. actinomycetemcomitans to define the antigenic specificities of IgG, IgM, IgA, and IgG1-4 antibody to A. actinomycetemcomitans strain Y4 outer membrane antigens (OMA). Uniform IgG antibody (> 70% of the patients) was noted to antigens with M(r) of 65, 38, 29, and 17 kDa. Both IgA and IgM specificities reflected those shown for IgG in each patient. IgG1 and IgG2 antibody reacted with several OMA bands in each patient, while IgG3 antibodies were directed to numerous OMA bands in many patients and represented the most broad-based response. The IgG4 response patterns were limited to a few OMA bands. We noted a prominent occurrence of IgG reactions with OMA bands that were characteristic for individual patients. The frequency of responses to OMA of higher M(r) (i.e., > 80 kDa) and to the 34-, 31-, and 24-kDa antigens was positively related to the total IgG antibody levels. Antibody reactive with OMA bands at 65-, 38-, 29-, 17-, 15-, and 11-kDa antigens was detected in patients with few to many teeth infected with A. actinomycetemcomitans. Furthermore, patients with a high percentage of teeth with > or = 6 mm pockets had a decreased frequency of responses to the high-M(r) antigens (i.e. > 90 kDa) as well as to the 58-kDa antigen.(ABSTRACT TRUNCATED AT 250 WORDS)

Subgingival distribution of A. actinomycetemcomitans in periodontitis

This investigation developed an experimental design that (1) detailed the distribution of A. actinomycetemcomitans in subgingival plaque related to the level of serum antibody to this pathogen; (2) used broad based subgingival plaque sampling to allow a definition of the distribution of A. actinomycetemcomitans infection in periodontitis patients; (3) described the distribution of A. actinomycetemcomitans serotypes in patients and within sites; and, (4) assessed how this infection impacted upon local clinical symptoms of disease. We noted a significant positive relationship between the level of IgG anti-A. actinomycetemcomitans antibody and the frequency of teeth infected until nearly 13 teeth demonstrated an infection. Furthermore, the results showed a generally negative relationship between the antibody level and the burden of A. actinomycetemcomitans in the infected sites. Interproximal sites associated with first molar teeth were the predominant sites for subgingival colonization; incisors were also frequently infected in this population. The first molar teeth also exhibited the greatest level of A. actinomycetemcomitans, while the incisors demonstrated a high level of A. actinomycetemcomitans in individual sites. The results clearly indicated the majority of the sites sampled were colonized by a single serotype of A. actinomycetemcomitans. We detected A. actinomycetemcomitans nearly 2 x times more frequently and a significant increase in the proportion of A. actinomycetemcomitans was found in samples obtained from teeth with bleeding on probing. The results also showed a significant trend for both pocket depth and attachment levels to be related to the presence and proportion of A. actinomycetemcomitans in the subgingival plaque. These findings detail the microbiological, immunological and clinical characteristics of a unique subset of periodontitis patients that appear to exhibit disease associated (caused?) with A. actinomycetemcomitans infection irrespective of clinical categorization. The results support a unique distribution of this microorganism in the subgingival ecology that is related to active host immune responses and clinical presentation of the tooth.

Serum antibody in Actinobacillus actinomycetemcomitans-infected patients with periodontal disease

This study was designed to (i) delineate the characteristics of serum antibody responses to Actinobacillus actinomycetemcomitans in patients with periodontitis who are infected with A. actinomycetemcomitans; irrespective of disease classification; (ii) assess the relationship of the elevated antibody levels to colonization of the oral cavity by A. actinomycetemcomitans; and (iii) describe the serotype distribution of A. actinomycetemcomitans and antibodies to the microorganism in infected patients with various clinical classifications. To compare the levels of various isotype-specific antibodies to the different antigens, studies were performed that allowed quantitation of each isotype-specific antibody in a human reference standard. By using this reference standard, it was shown that the levels of immunoglobulin G (IgG), IgM, and IgA responses to A. actinomycetemcomitans were similar among the infected patients, irrespective of disease classification. Also, we demonstrated that the serum antibody response to serotype b was quantitatively greater in all isotypes. Our findings indicate that b was the most frequent A. actinomycetemcomitans serotype detected in the patients and appears to be capable of initiating a substantial serum IgG antibody response that may contain cross-reactive antibodies to other serotypes of A. actinomycetemcomitans. Generally, in cases in which the response to a single serotype was elevated, only that type of A. actinomycetemcomitans was detected in the plaque. Individuals exhibiting elevated antibodies to multiple serotypes were most consistently colonized by the serotype b microorganism. This study represents the first report detailing the distribution of IgG subclass antibodies to A. actinomycetemcomitans in periodontal disease. The results demonstrated that the primary responses of patients with periodontitis to A. actinomycetemcomitans were of the IgG1 and IgG3 subclasses, which is consistent with elicited responses to protein antigens. In contrast, the primary subclass response in normal subjects was limited to the IgG2 subclass and may represent broader cross-reactivity to polysaccharide antigens-lipopolysaccharide from the bacteria.