Pharmacist-led telehealth deprescribing for people living with dementia and polypharmacy in primary care: A pilot study

BACKGROUND

People living with dementia (PLWD) have complex medication regimens, exposing them to increased risk of harm. Pragmatic deprescribing strategies that align with patient-care partner goals are needed.

METHODS

A pilot study of a pharmacist-led intervention to optimize medications with patient-care partner priorities, ran May 2021-2022 at two health systems. PLWD with ≥7 medications in primary care and a care partner were enrolled. After an introductory mailing, dyads were randomized to a pharmacist telehealth intervention immediately (intervention) or delayed by 3 months (control). Feasibility outcomes were enrollment, intervention completion, pharmacist time, and primary care provider (PCP) acceptance of recommendations. To refine pragmatic data collection protocols, we assessed the Medication Regimen Complexity Index (MRCI; primary efficacy outcome) and the Family Caregiver Medication Administration Hassles Scale (FCMAHS).

RESULTS

69 dyads enrolled; 27 of 34 (79%) randomized to intervention and 28 of 35 (80%) randomized to control completed the intervention. Most visits (93%) took more than 20 min and required multiple follow-up interactions (62%). PCPs responded to 82% of the pharmacists' first messages and agreed with 98% of recommendations. At 3 months, 22 (81%) patients in the intervention and 14 (50%) in the control had ≥1 medication discontinued; 21 (78%) and 12 (43%), respectively, had ≥1 new medication added. The mean number of medications decreased by 0.6 (3.4) in the intervention and 0.2 (1.7) in the control, reflecting a non-clinically meaningful 1.0 (±12.4) point reduction in the MRCI among intervention patients and a 1.2 (±12.9) point increase among control. FCMAHS scores decreased by 3.3 (±18.8) points in the intervention and 2.5 (±14.4) points in the control.

CONCLUSION

Though complex, pharmacist-led telehealth deprescribing is feasible and may reduce medication burden in PLWD. To align with patient-care partner goals, pharmacists recommended deprescribing and prescribing. If scalable, such interventions may optimize goal-concordant care for PLWD.

Participant perspectives on the impact of receiving medically tailored meals on post-hospitalization

OBJECTIVE

The objective of this program evaluation was to measure the impact of a medically tailored meals (MTM) intervention on participants' self-reported recovery and satisfaction while recovering from a recent hospitalization.

DESIGN

A qualitative design was employed using a brief survey among all participants at the end of the intervention and phone interviews with a subset of participants.

SAMPLE

Participants in this study were recently discharged from the hospital and were members of (redacted for review) who had received 2-4 weeks of MTM.

MEASUREMENTS

The survey assessed overall satisfaction with the meals and perceived impact on their recovery after hospitalization (81% response rate). Interview questions asked how they felt the meals may have helped while recovering (e.g., helped them financially or with their ability to remain independent).

RESULTS

Among survey participants, 65% were extremely or very satisfied with their meals. Reasons that MTM were helpful while they were recovering included having sufficient food to eat, having healthy food to eat, the convenience of the meals, and ease of preparing the meals.

CONCLUSIONS

Participants receiving MTM were generally very satisfied with the program. Including nutrition education and more flexibility in quantity and frequency of food may improve satisfaction and consumption of food.

HOW CAN PATIENT PORTALS SUPPORT CAREGIVERS PROVIDING END-OF-LIFE CARE?: A MIXED-METHODS STUDY

Patient portal design is rarely centered around patient caregivers—family members, friends and other designated persons who may access these digital tools for the patient’s health needs. This study examines: (a) portal features used by caregivers during their loved-one’s end-of-life; and (b) caregiver perceptions regarding the use of patient portals for caregiving near the end-of-life.Using sequential mixed-methods, we conducted a retrospective cohort analysis of caregiver proxy (N=137) use from 2016-2019 during their loved-ones’ (N=5,284) last 12 months of life and interviews with (N=31) 16-former and 15-current caregiver proxies. Caregiver proxy portal use in this population was lower than expected; however, caregivers who used the portal as proxies found value in tools for caregiving near the end-of-life. To leverage the patient portal to better support caregivers, future strategies should target caregiver portal adoption, awareness of beneficial portal tools, and the addition of caregiver specific resources and education.

Recommendations for outcome measurement for deprescribing intervention studies

Interpreting results from deprescribing interventions to generate actionable evidence is challenging owing to inconsistent and heterogeneous outcome definitions between studies. We sought to characterize deprescribing intervention outcomes and recommend approaches to measure outcomes for future studies. A scoping literature review focused on deprescribing interventions for polypharmacy and informed a series of expert panel discussions and recommendations. Twelve experts in deprescribing research, policy, and clinical practice interventions participating in the Measures Workgroup of the US Deprescribing Research Network sought to characterize deprescribing outcomes and recommend approaches to measure outcomes for future studies. The scoping review identified 125 papers reflecting 107 deprescribing studies. Common outcomes included medication discontinuation, medication appropriateness, and a broad range of clinical outcomes potentially resulting from medication reduction. Panel recommendations included clearly defining clinically meaningful medication outcomes (e.g., number of chronic medications, dose reductions), ensuring adequate sample size and follow-up time to capture clinical outcomes resulting from medication discontinuation (e.g., quality of life [QOL]), and selecting appropriate and feasible data sources. A new conceptual model illustrates how downstream clinical outcomes (e.g., reduction in falls) should be interpreted in the context of initial changes in medication measures (e.g., reduction in mean total medications). Areas needing further development include implementation outcomes specific to deprescribing interventions and measures of adverse drug withdrawal events. Generating evidence to guide deprescribing is essential to address patient, caregiver, and clinician concerns about the benefits and harms of medication discontinuation. This article provides recommendations and an initial conceptual framework for selecting and applying appropriate intervention outcomes to support deprescribing research.

Intervention Design With Cognitively Impaired Populations: The Optimize Deprescribing Intervention

Older adults with cognitive impairment and multiple other chronic conditions often have polypharmacy which increases their risks of medication related cognitive effects, adverse drug events, hospitalization and death and leads to higher health care costs. Deprescribing, the process of reducing or stopping potentially inappropriate medications may improve outcomes for those older adults with cognitive impairment and multiple chronic conditions. The OPTIMIZE trial examined whether a primary care-based, patient- and family-centered intervention educating and activating patients, family members, and clinicians about deprescribing reduces numbers of chronic medications and potentially inappropriate medications for older adults with dementia or mild cognitive impairment and multiple chronic conditions. We explored the mechanisms of intervention effectiveness through post hoc qualitative stakeholder interviews and surveys with 15 patients, 7 family caregivers, and 28 clinicians. All stakeholder groups endorsed the acceptability of the intervention. Success of the intervention was affected by contextual factors including prior knowledge and openness to deprescribing, cognition and prognosis. Positive outcomes included patients and care partners scheduling specific appointments to discuss deprescribing and providers remembering to consider deprescribing in cognitively impaired older adults. Recollection of intervention materials was inconsistent over time but highest shortly after intervention delivery. The time required to mail intervention materials to patients prior to a scheduled appointment limited the reach of the intervention by excluding persons with rapidly scheduled appointments. Our work identifies key learnings in intervention roll out which can guide future translation of our intervention to other settings and other pragmatic intervention studies in this vulnerable population.

Aligning care with the personal values of patients with complex care needs

OBJECTIVE

To identify opportunities to align care with the personal values of patients from three distinct groups with complex medical, behavioral, and social needs.

DATA SOURCES/STUDY SETTING

Between June and August 2019, we conducted semi-structured interviews with individuals with complex care needs in two integrated health care delivery systems.

STUDY DESIGN

Qualitative study using semi-structured interviews.

DATA COLLECTION METHODS

We interviewed three groups of patients at Kaiser Permanente Washington and Kaiser Permanente Colorado representing three distinct profiles of complex care needs: Group A ("obesity, opioid prescription, and low-resourced neighborhood"), Group B ("older, high medical morbidity, emergency department, and hospital use"), and Group C ("older, mental and physical health concerns, and low-resourced neighborhood"). These profiles were identified based on prior work and prioritized by internal primary care stakeholders. Interview transcripts were analyzed using thematic analysis.

PRINCIPAL FINDINGS

Twenty-four patients participated; eight from each complex needs profile. Mean age across groups was 71 (range 48-86) years. We identified five themes common across the three groups that captured patients' views regarding values-aligned care. These themes focused on the importance of care teams exploring and acknowledging a patient's values, providing access to nonphysician providers who have different perspectives on care delivery, offering values-aligned mental health care, ensuring connection to community-based resources that support values and address needs, and providing care that supports the patient plus their family and caregivers.

CONCLUSIONS

Our results suggest several opportunities to improve how care is delivered to patients with different complex medical, behavioral, and social needs. Future research is needed to better understand how to incorporate these opportunities into health care.

Perceptions of Patient Portal Use for Advance Directive Documentation among Older Adults with Multiple Chronic Conditions

Patient portals can play an innovative role in facilitating advanced care planning (ACP) and documenting advance directives (ADs) among older adults with multiple chronic conditions. The objective of this qualitative sub-study was to (1) understand older adults' use of an ACP patient portal section and (2) obtain user-design input on AD documentation features. Although some older adults may be reluctant, participants reported likely to use a portal for ADs with proper portal design and support.

CALL A TEENAGER . . . THAT’S WHAT I DO!: GRANDCHILDREN HELP OLDER ADULTS USE NEW TECHNOLOGIES

As older adults increasingly show interest in technology for their well-being, families will play an important role in promoting the adoption and use of beneficial health technologies. The purpose of this study was to conduct a sub-analysis of data collected from a large-scale qualitative project regarding older adults’ experiences using health information technology. Specifically, the sub-analysis explored older adults’ experiences with technology support from family members to inform strategies for promoting older adult engagement with new health technologies. While the primary analysis of the original study was theoretically driven, this paper reports results from the inductive, open-coding analysis. Twenty-four older patients (≥65 years) with multiple chronic conditions (Charlson Comorbidity Index > 2) participated in a focus group conducted at patients’ primary clinic. While conducting the primary theoretically-driven analysis, coders also utilized an open-coding approach to ensure important ideas not reflected in the theoretical code-book were captured. Open-coding resulted in a primary theme, “family support”, that was furthered categorized by who and how the tech-support was provided. Participants were not specifically asked about family support, yet family assistance and encouragement for technology emerged from every focus group. Participants repeatedly mentioned that they called their grandchildren and adult children for help with technology. Participants also reported that family members experienced difficulty when teaching technology use. Family members struggled to explain simple technology tasks and were frustrated by the slow teaching process. Family support, specifically via grandchildren, may have a key role in the successful adoption and use of emerging health technologies.

"Call a Teenager… That's What I Do!" - Grandchildren Help Older Adults Use New Technologies: Qualitative Study

Background

Although family technical support seems intuitive, there is very little research exploring this topic.

Objective

The objective of this study was to conduct a subanalysis of data collected from a large-scale qualitative project regarding older adults’ experiences in using health information technology. Specifically, the subanalysis explored older adults’ experiences with technology support from family members to inform strategies for promoting older adults’ engagement with new health technologies. Although the primary analysis of the original study was theoretically driven, this paper reports results from an inductive, open-coding analysis.

Methods

This is a subanalysis of a major code identified unexpectedly from a qualitative study investigating older adults’ use experience of a widespread health technology, the patient portal. A total of 24 older patients (≥65 years) with multiple chronic conditions (Charlson Comorbidity Index >2) participated in focus groups conducted at the patients’ primary clinic. While conducting the primary theoretically driven analysis, coders utilized an open-coding approach to ensure important ideas not reflected in the theoretical code book were captured. Open coding resulted in 1 code: family support. This subanalysis further categorized family support by who provided tech support, how tech support was offered, and the opinions of older participants about receiving family tech support.

Results

The participants were not specifically asked about family support, yet themes around family assistance and encouragement for technology emerged from every focus group. Participants repeatedly mentioned that they called their grandchildren and adult children if they needed help with technology. Participants also reported that family members experienced difficulty when teaching technology use. Family members struggled to explain simple technology tasks and were frustrated by the slow teaching process.

Conclusions

The results suggest that older adults ask their family members, particularly grandchildren, to support them in the use of new technologies. However, family may experience difficulties in providing this support. Older adults will be increasingly expected to use health technologies, and family members may help with tech support. Providers and health systems should consider potential family support and engagement strategies to foster adoption and use among older patients.

'Reducing Delays In Vaccination' (REDIVAC) trial: a protocol for a randomised controlled trial of a web-based, individually tailored, educational intervention to improve timeliness of infant vaccination

INTRODUCTION

Increasing numbers of children are failing to receive many recommended vaccines, which has led to significant outbreaks of vaccine-preventable diseases in the USA and worldwide. A major driver of undervaccination is parental vaccine hesitance. Prior research demonstrates that mothers are the primary decision maker for infant vaccination, and that their vaccination attitudes form primarily during pregnancy and early in their infant's life.

METHODS AND ANALYSIS

This manuscript describes the protocol for an ongoing three-armed randomised controlled trial done at Kaiser Permanente Colorado (KPCO). The trial aims to test the efficacy of provided tailored, individualised information via the Internet to pregnant and new mothers versus untailored information versus usual care on the timeliness of infant vaccination. The primary outcome to be assessed is vaccination status, which is a dichotomous outcome (up to date vs not) assessed at age 200 days, reflecting the time when infants should have completed the first set of vaccine provided (at age 2, 4 and 6 months). Infants with one or more age-appropriate recommended vaccines at least 30 days delayed are categorised as not up to date whereas all other infants are considered up to date. Secondary outcomes include vaccination status at age 489 days, reflecting receipt of recommended vaccines at age 12-15 months, as well as vaccination attitudes, hesitancy and intention. Vaccination data will be derived from the electronic medical record and the state immunisation registry. Other secondary outcomes will be assessed by online surveys.

ETHICS AND DISSEMINATION

The study activities were approved by the Institutional Review Boards of the University of Colorado, KPCO and the University of Michigan. Results will be disseminated through peer-reviewed manuscripts and conference presentations.

TRIAL REGISTRATION NUMBER

NCT02665013; Pre-results.

Using the Technology Acceptance Model to Explore User Experience, Intent to Use, and Use Behavior of a Patient Portal Among Older Adults With Multiple Chronic Conditions: Descriptive Qualitative Study

Background

Patient portals offer modern digital tools for older adults with multiple chronic conditions (MCC) to engage in their health management. However, there are barriers to portal adoption among older adults. Understanding portal user interface and user experience (UI and UX) preferences of older adults with MCC may improve the accessibility, acceptability, and adoption of patient portals.

Objective

The aim of this study was to use the Technology Acceptance Model (TAM) as a framework for qualitatively describing the UI and UX, intent to use, and use behaviors among older patients with MCC.

Methods

We carried out a qualitative descriptive study of Kaiser Permanente Colorado’s established patient portal, My Health Manager. Older patients (N=24; mean 78.41 (SD 5.4) years) with MCC participated in focus groups. Stratified random sampling was used to maximize age and experience with the portal among participants. The semistructured focus groups used a combination of discussion and think-aloud strategies. A total of 2 coders led the theoretically driven analysis based on the TAM to determine themes related to use behavior, portal usefulness and ease of use, and intent to use.

Results

Portal users commonly used email, pharmacy, and lab results sections of the portal. Although, generally, the portal was seen to be easy to use, simple, and quick, challenges related to log-ins, UI design (color and font), and specific features were identified. Such challenges inhibited participants’ intent to use the portal entirely or specific features. Participants indicated that the portal improved patient-provider communication, saved time and money, and provided relevant health information. Participants intended to use features that were beneficial to their health management and easy to use.

Conclusions

Older adults are interested in using patient portals and are already taking advantage of the features available to them. We have the opportunity to better engage older adults in portal use but need to pay close attention to key considerations promoting usefulness and ease of use.

The impact of randomized trial results and altered regulatory policies on ESA use, transfusions, and thrombosis: A longitudinal analysis over a 3-year period of resource utilization data from a large comprehensive oncology program

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Background: Recent randomized trials and meta-analyses demonstrated unexpected findings with ESA use with chemotherapy. Results revealed an overall increase in thrombosis rates with the use of ESAs as well as decrements in survival in some malignancies, particularly with breast and head and neck cancers (Bohlius, JNCI, 2006; Raftopoulos, Proc ASCO, 2008; Bennett, JAMA 2008). Benefits with ESA use have resulted in an average 1–1.5g/dl rise in hemoglobin. The impact on quality of life and fatigue remains controversial. Toxicity issues have led to restricted labeling by the FDA and reimbursement decisions by the Centers for Medicare and Medicaid Services (CMS). Despite these risks associated with the use of ESAs, concerns regarding increased use of transfusions remain prominent. A longitudinal study to assess the impact of these ESA policies was conducted to assess the demand on transfusion services and ESA use over time. Methods: Our center comprises a large comprehensive combined hematology and oncology program and has a non- restrictive transfusion policy, allowing physician discretion and the capacity to accommodate all out-patient transfusions. We analyzed ESA use over the 3 year period, 2006–2008. 2006 functioned as our baseline; 2007 was the year of initial FDA and CMS changes; 2008 allowed us to see if practice changes would persist. Results: We present in the table below, our data on ESA use and transfusion resource utilization. Conclusions: With over 60,000 patient visits during 3 years, longitudinal assessment reveals a continued, marked decrease in ESA use. Despite liberal transfusion policies, there has been little effect on transfusion rates. Increases in transfusions are commensurate with a rise in patient visit volume. We are now evaluating whether this marked decrease in ESA use translates into decreased thrombosis rates over this 3-year period at our cancer center.

[Table: see text]

No significant financial relationships to disclose.

Recombinant erythropoietin (Epo)/darbepoetin (Darb) associated venous thromboembolism (VTE) in the oncology setting: Findings from the Research on Adverse Drug Events And Reports (RADAR) project

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Background: Cancer patients are at increased risk for VTE as compared to the general population, making VTE as a sADR difficult to detect in the oncology setting. In 2004, two phase III trials identified higher mortality rates among epo-treated cancer patients who were receiving chemotherapy in “off-label” settings- with these studies identifying higher VTE rates in the treatment arms. We reviewed data on epo/darb-associated VTE in the oncology setting. Methods: Data sources were meta-analyses and the FDA’s MedWatch database. Results: Since 1996, only 259 VTE reports (darb: n=30, epo: n=229) of VTE in the setting of chemotherapy and epo/darb were reported to MedWatch. Meta-analyses findings are tabulated below: Conclusions: In 2004, package inserts for Epo/Darb were revised, identifying increased risks of VTE with these agents in the oncology setting. Identification of this adverse drug reaction thirteen years after Epo received FDA approval for this indication (and had been prescribed to > 500,000 cancer patients) illustrates difficulties inherent with current pharmacovigilance efforts.

[Table: see text]

No significant financial relationships to disclose.

Clinical trials, case reports, and observational databases as sources of information on serious cancer-related adverse drug reactions (sADRs): Lessons learned from the Research on Adverse Drug Events and Reports (RADAR) project

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Background: Serious adverse drug reactions (sADRs) such as venous thromboembolism resulting from cancer pharmaceutical use are underappreciated and often misattributed to the cancer diagnosis, rather than the therapy. The Research on Adverse Drug events And Reports (RADAR) group evaluated factors associated with identification of serious cancer-related sADRs (i.e. an adverse drug reaction that results in death or severe organ failure). Methods: Information on sources of clinical information, incidence, setting, and time from FDA approval to initial identification was obtained for sADRs that resulted in death or severe organ failure. Most of the ADRs are described as Black Box warnings or in “Dear Doctor” letters. Results: Summarized in table . Conclusion: Clinical trial safety reports from off-label settings facilitate identification of common (>3% rate) cancer associated sADRs. Case reports and observational databases from on-label settings facilitate detection of rare cancer-associated sADRs (<1%) often at lengthy time intervals from initial FDA approval.

No significant financial relationships to disclose.

[Table: see text]

Sequential magnetic resonance monitoring of pulmonary flow with endovascular stents placed across the pulmonary valve in growing Swine

BACKGROUND

Patients with endovascular stent implantation for the treatment of right ventricular outflow tract obstruction are often left with incomplete relief of the obstruction and significant pulmonary regurgitation. A noninvasive and reproducible method for monitoring such patients is desirable. MRI in the presence of a stent, however, has to overcome the problem of potential metallic artifacts.

METHODS AND RESULTS

Under x-ray fluoroscopic guidance, endovascular nitinol stents were placed across the pulmonary valve in 6 young pigs to induce pulmonary regurgitation. Five additional pigs served as controls. Initial MRI was performed after 2 days (13.5+/-1.8 kg) and follow-up after 3 months (32+/-2.9 kg). Pulmonary flow volumes and regurgitant fraction were quantified by velocity-encoded cine (VEC) MRI through (VEC-TS) and distal to (VEC-DS) the stent. VEC-TS was compared with VEC-DS and volumetric measurements of left and right ventricular stroke volumes provided by cine MRI ("gold standard"). Antegrade and retrograde pulmonary flow volumes by VEC-TS were slightly but significantly less than those with VEC-DS and cine MRI. Excellent correlations (r>0.97) for phasic pulmonary flow volumes as measured by VEC-TS and VEC-DS were shown. Pulmonary regurgitant fraction increased from 32.8+/-15% to 49.6+/-17% (P<0.05) over the course of 3 months with VEC-TS.

CONCLUSIONS

MRI demonstrates the progression of pulmonary regurgitation in growing swine. VEC MRI has the ability to quantify pulmonary blood flow inside the lumen of nitinol stents. MRI appears to be ideally suited for monitoring patients with endovascular nitinol stents in the pulmonary artery or pulmonary valve position.

Clinical comparison of St. Jude and porcine mitral valve prostheses

One hundred and six consecutive patients who had mitral valve replacement with either a St. Jude or porcine heterograft prosthesis were prospectively studied. The 2 groups are similar with respect to 67 clinical and operative factors and allow comparison of valve performance as an independent variable. Total follow-up is 3,312 patient-months (mean 36 months, range 2-57 months, 94% complete). There are no statistical differences in symptomatic improvement or mortality by life table analysis. Valve-related complications expressed as percent per patient-year are: reoperation: 1.8 St. Jude and 3.8 porcine; endocarditis: 1.2 and 1.9; regurgitant murmur: 2.3 and 1.9; hemolysis: 1.8 and 0.0; late thromboembolism: 1.8 and 1.0; hemorrhage: 2.9 and 2.9; and valve failure: 0.0 and 1.0. There were no significant differences found. Actuarial survival at 3 years was 78% in St. Jude and 81% in porcine patients. Forty-six percent of patients with St. Jude valves and 55% of patients with porcine valves were alive and free of all complications at latest follow-up. The clinical performance of St. Jude and porcine mitral valves are similar over this period of intermediate follow-up.

Familial IgA nephropathy. Evidence of an inherited mechanism of disease

The evaluation of familial glomerulonephritis in patients with IgA nephropathy who were from central and eastern Kentucky resulted in the discovery of potentially related pedigrees containing 14 patients. An additional 17 members of the pedigrees had clinical glomerulonephritis, and 6 had "chronic nephritis" noted on their death certificates. Six patients with IgA nephropathy had a common ancestor. In addition, both parents of six patients with the disease came from families with other cases of IgA nephropathy. No single HLA haplotype or antigen was found in all the patients with IgA nephropathy. Our data on these pedigrees strongly support an inherited mechanism in the pathogenesis of IgA nephropathy in some patients.

T-cell helper circuits

T helper cells specific for trinitrophenylated PC-binding myeloma and hybridoma antibodies are induced by priming with PC antigen, idiotype or anti-idiotypic antibody. These T helper cells are specific for a shared idiotope present on T15 and M167. Priming with the isolated heavy chains of T15 or M167, or the light chain of anti-T15 hybridoma antibody is equally effective in generating T helper cells. Evidently, the idiotope that is recognized by T cells is not dependent upon the conformation of the 7s Ig molecule. Collectively, these and other findings indicate the existence of a TH1-TH2-B cellular circuit which is based on the recognition of idiotopic determinants on T cell receptors. The implications of these findings in terms of network theory are explored.

Idiotype-specific T-helper cells

In the present study we investigated the induction and fine specificity of T-helper cells that recognize idiotypes. The data presented show that both low-dose priming with anti-T15 antiserum and priming with PC-Hy are effective in stimulating T15-specific T help. Phosphorylcholine-hemocyanin priming can generate these T cells in either PC-responding or nonresponding strains of mice. Furthermore, the PC-primed T-helper cells can also recognize another anti-PC myeloma, M167, that is idiotypically different from T15. The fine specificity of the anti-PC-idiotype recognizing T-helper cells was examined by studying the effect of in vitro inhibitors on the T-cell help. Both PC and PC-BSA as well as T15 and M167 had an inhibitory effect on the T help. Free T15 and M167 heavy chains also blocked the helper activity for T15; T15 and M167 light chains had no effect, however. Viewed collectively, these results show that PC-Hy priming induces T-helper cells that recognize idiotypic determinants common to both T15 and M167, and that the proteins' H chain is the major structural component of the determinant. Finally, the generation of these idiotype-recognizing T cells was found to occur by way of a T-T interaction loop, based on the finding that T-helper cells are induced by PC-Hy priming in animals that lack PC-responding B cells.

Regulatory idiotypes. T helper cells recognize a shared VH idiotope on phosphorylcholine-specific antibodies

Priming of BALB/c mice with phosphorylcholine-hemocyanin (PC-Hy) induces T helper cells that are detected in splenic fragment cultures responding to immunization with trinitrophenylated PC-binding myeloma proteins, TEPC 15 (TNP-T15) and MOPC 167 (TNP-M167). Trinitrophenylation did not alter the binding site, idiotype, or isotype of the antibodies as demonstrated by binding studies. To assay idiotype-recognizing helper cells, Ly-2.2-depleted T cells from PC-Hy-primed donor mice were transferred to syngeneic athymic mice. Splenic anti-trinitrophenol fragment cultures were prepared from the nude recipients, and the response to TNP-T15 and TNP-M167 was measured by enzyme-linked immunosorbent assay. The number of responding fragments is dependent on the number of transferred primed T cells. The homing efficiency of 51Cr-labeled helper cells into the spleen of nude recipients was determined. The frequencies of T helper cells taken from PC-Hy-primed donors required for a B cell response to TNP-T15 or TNP-M167 were indistinguishable. The fine specificity of the anti-PC idiotype-recognizing T helper cells was studied by adding hapten (PC) or unconjugated myeloma proteins to fragment cultures as inhibitors at the time of immunization. PC and PC-bovine serum albumin, as well as T15 and M167, inhibited the helper function in vitro. Furthermore, free heavy chains of T15 and M167 partially inhibited T help, but free light chains of both idiotypes had no effect. These findings collectively show that T helper cells, induced by priming with antigen, recognize a shared idiotypic determination on T15 and M167 that is part of the PC binding site. The heavy chains of T15 and M167 appears to be the major structural component of this determinant. Evidently, T helper cells can recognize a shared determinant that is present on idiotypically different myeloma proteins. This determinant appears to be conserved throughout evolutionary and somatic mutations. The role of this shared, binding site-related idiotypic determinant as a regulatory idiotype in T-B cell interaction is discussed.

Balb/c T cells have the potential to recognize the TEPC 15 prototype antibody and its somatic variants

Immunization of BALB/c mice with phosphorylcholine-Limulus polyphemus hemocyanin (PC-Hy) induces a population of T cells that recognize the predominant PC-binding antibody, TEPC15 (T15). The splenic fragment culture system was used to examine the specificity of these T cells for a series of PC-binding myeloma and hybridoma antibodies representing the prototype variable region of the heavy chain (VH)T 15 sequence as well as somatic variants of the T15 germ line-encoded sequence. Included in this group of PC-binding proteins were both T15-positive and T15-negative antibodies, as defined by anti-idiotypic antibody. T cell help was identified by the ability to promote TNP-specific B cell responses to trinitrophenylated PC-binding proteins. It was found that T cells generated by immunization with PC-Hy recognize both antibodies with the T15 prototype sequence and the putative somatic variants of this sequence. A population of these T cells appear to recognize common determinants shared by these proteins because immunization with T15 itself also induces the recognition of the somatic variants. This suggests that idiotopes encoded in the T15 germ line gene expressed by the T15 prototype idiotype and the somatic variants can function as targets for T cell recognition and are thus regulatory idiotopes.

Generation of idiotype-specific T cell help through network perturbation

Different manipulations of BALB/c mice were used to generate idiotype-specific help: neonatally induced suppression of the T 15 idiotype and low-dose priming with anti-T15 antibody. The splenic foci culture system was used to study T15-idiotype-recognizing helper T cells under limiting-cell-dose conditions. These treatments induced T15 idiotype-specific help for B cells responding to TNP-T15. Normal or hemocyanin-primed BALB/c mice did not supply T15 idiotype-specific help. The helper cells were sensitive to anti-Thy-1.2 and complement treatment and can distinguish T15 from an idiotype-different, PC-binding myeloma protein, M167, and the TNP binding myeloma protein, M460. These data show that idiotype-specific T helper cells can be induced by at least two different manipulations of the idiotype network. These manipulations presumably do not act directly on the T15-recognizing T cells, but must involve complementary idiotypic circuits that stimulate anti-T15 specific T cells. Furthermore, this study demonstrates that the splenic-fragment culture technique provides a general method to investigate, at the single cell level, idiotypic T-B cell interactions induced by perturbations of the immune network.