Treatments for spasticity and pain in multiple sclerosis: a systematic review

OBJECTIVES

To identify the drug treatments currently available for the management of spasticity and pain in multiple sclerosis (MS), and to evaluate their clinical and cost-effectiveness.

DATA SOURCES

Electronic bibliographic databases, National Research Register, MRC Clinical Trials Register and the US National Institutes of Health Clinical Trials Register.

REVIEW METHODS

Systematic searches identified 15 interventions for the treatment of spasticity and 15 interventions for treatment of pain. The quality and outcomes of the studies were evaluated. Reviews of the treatment of spasticity and pain when due to other aetiologies were also sought.

RESULTS

There is limited evidence of the effectiveness of four oral drugs for spasticity: baclofen, dantrolene, diazepam and tizanidine. Tizanidine appears to be no more effective than comparator drugs such as baclofen and has a slightly different side-effects profile. Despite claims that it causes less muscle weakness, there was very little evidence that tizanidine performed any better in this respect than other drugs, although it is more expensive. The findings of this review are consistent with reviews of the same treatments for spasticity derived from other aetiologies. There is good evidence that both botulinum toxin (BT) and intrathecal baclofen are effective in reducing spasticity, and both are associated with functional benefit. However, they are invasive, and substantially more expensive. None of the studies included in the review of pain were designed specifically to evaluate the alleviation of pain in patients with MS and there was no consistency regarding the use of validated outcome measures. It was suggested that, although expensive, the use of intrathecal baclofen may be associated with significant savings in hospitalisation costs in relation to bed-bound patients who are at risk of developing pressure sores, thus enhancing its cost-effectiveness. No studies of cost-effectiveness were identified in the review of pain. There is evidence, albeit limited, of the clinical effectiveness of baclofen, dantrolene, diazepam, tizanidine, intrathecal baclofen and BT and of the potential cost-effectiveness of intrathecal baclofen in the treatment of spasticity in MS.

CONCLUSIONS

Many of the interventions identified are not licensed for the alleviation of pain or spasticity in MS and the lack of evidence relating to their effectiveness may also limit their widespread use. Indeed, forthcoming information relating to the use of cannabinoids in MS may result in there being better evidence of the effectiveness of new treatments than of any of the currently used drugs. It may therefore be of value to carry out double-blind randomised controlled trials of interventions used in current practice, where outcomes could include functional benefit and impact on quality of life. Further research into the development and validation of outcomes measures for pain and spasticity may also be useful, as perhaps would cost-utility studies.

Cooperation of structural proteins during late events in the life cycle of polyomavirus

The polyomavirus minor late capsid antigen, VP2, is myristylated on its N-terminal glycine, this modification being required for efficient infection of mouse cells. To study further the functions of this antigen, as well as those of the other minor late antigen, VP3, recombinant baculoviruses carrying genes for VP1, VP2, and VP3 have been constructed and the corresponding proteins have been synthesized in insect cells. A monoclonal antibody recognizing VP1, alpha-PyVP1-A, and two monoclonal antibodies against the common region of VP2 and VP3, alpha-PyVP2/3-A and alpha-PyVP2/3-B, have been generated. Reactions of antibodies with antigens were characterized by indirect immunofluorescence, immunoprecipitation, and immunoblot analysis. Immunofluorescent staining of mouse cells infected with polyomavirus showed all antigens to be localized in nuclei. When the late polyomavirus proteins were expressed separately in insect cells, however, only VP1 was efficiently transported into the nucleus; VP2 was localized discretely around the outside of the nucleus, and VP3 exhibited a diffused staining pattern in the cytoplasm. Coexpression of VP2, or VP3, with VP1 restored nuclear localization. Immunoprecipitation of infected mouse cells with either anti-VP1 or anti-VP2/3 antibodies precipitated complexes containing all three species, consistent with the notion that VP1 is necessary for efficient transport of VP2 and VP3 into the nucleus. Purified empty capsid-like particles, formed in nuclei of insect cells coinfected with all three baculoviruses, contained VP2 and VP3 proteins in amounts comparable to those found in empty capsids purified from mouse cells infected with wild-type polyomavirus. Two-dimensional gel analysis of VP1 species revealed that coexpression with VP2 affects posttranslational modification of VP1.

Chronic anemia due to parvovirus B19 infection in a bone marrow transplant patient after platelet transfusion

BACKGROUND

Many reports document the transmission of human parvovirus B19 (B19) infection by clotting factor concentrates manufactured from large plasma pools. Transmission via other blood components originating from a single donor or a small number of donors, however, seems to occur only rarely. The study reported here identifies a B19 infection that was transmitted via a platelet donation.

CASE REPORT

A multiply transfused allogeneic bone marrow transplant patient developed chronic anemia due to persistent B19 infection. The anemia responded to therapy with intravenous immunoglobulin. It was postulated that a transfusion was the source of the B19 infection. Archived sera from 90 implicated blood donors were tested for B19 IgM and DNA by the use of dot-blot hybridization and a nested polymerase chain reaction with primers from the B19 nonstructural gene. B19 DNA from patient and donor sera were sequenced. One of the 90 blood donors (Donor A) was B19 IgM positive and had a high level of B19 DNA. The patient was viremic 3 days after transfusion of platelets from this donor, and the sequence of B19 DNA from the patient exactly matched that of B19 DNA from the donor. A second blood donor (Donor B) had a low level of B19 DNA but was IgM negative. The patient showed no evidence of B19 infection after the transfusion of red cells from Donor B, and the sequence of this donor's B19 DNA was different from that in the patient.

CONCLUSION

Blood Donor A with asymptomatic acute B19 infection was the source of B19 infection in the bone marrow transplant patient. Donor B with a low level of B19 DNA was not the source of infection.

Genetic heterogeneity of mumps virus in the United Kingdom: identification of two new genotypes

A reverse transcriptase nested polymerase chain reaction (PCR) was developed to detect the small hydrophobic (SH) gene of mumps virus (MuV). Phylogenetic analysis was performed on the entire SH gene sequence (318 nucleotides) and the putative SH protein (57 amino acids). At least 4 MuV genotypes were identified in the United Kingdom between 1995 and 1998 by direct sequencing of 26 PCR amplicons from a variety of specimens. Comparison of these and GenBank sequences identified 2 new genotypes in the United Kingdom. The results suggest that, after the introduction of universal mumps vaccination in the United Kingdom in 1988, there appears to have been a switch from a predominant genotype to a heterogeneous group of strains.

The stress-response proteins poly(ADP-ribose) polymerase and NF-kappaB protect against bile salt-induced apoptosis

Bile salts induce apoptosis and are implicated as promoters of colon cancer. The mechanisms by which bile salts produce these effects are poorly understood. We report that the cytotoxic bile salt, sodium deoxycholate (NaDOC), activates the key stress response proteins, NF-kappaB and poly(ADP-ribose) polymerase (PARP). The activation of NF-kappaB and PARP, respectively, indicates that bile salts induce oxidative stress and DNA damage. The pre-treatment of cells with specific inhibitors of these proteins [pyrrolidine dithiocarbamate (NF-kappaB inhibitor) and 3-aminobenzamide (PARP inhibitor)] sensitizes cells to the induction of apoptosis by NaDOC, indicating that these stress response pathways are protective in nature. Colon cancer risk has been reported to be associated with resistance to apoptosis. We found an increase in activated NF-kappaB at the base of human colon crypts that exhibit apoptosis resistance. This provides a link between an increased stress response and colon cancer risk. The implications of these findings with respect to apoptosis and to colon carcinogenesis are discussed.

Long-term psychosocial adjustment following burn injury

Young adult survivors of severe childhood burn injuries were assessed for indicators of psychopathology and for factors that might enhance psychosocial adjustment. The results describe this group of burn victims as young people of average intelligence, still in school or otherwise employed and within normal limits on the measures of psychological adjustment. Some individuals, however, did evidence significant indicators of psychological disturbance. The only factors identified as significantly differentiating the most obviously disturbed subjects from the better-adjusted or well-adjusted victims were the perceptions held by those subjects that their families are less cohesive and less independent. These results emphasize the need to promote the familial support system and to encourage the values of autonomy and self-sufficiency. The results also affirm that severely injured burn victims can be expected to develop acceptably happy lives.

Clinical effectiveness of oral treatments for spasticity in multiple sclerosis: a systematic review

Spasticity is a common disabling feature of multiple sderosis. A variety of drugs are in regular use as oral treatment induding badofen, dantrolene, tizanidine, and diazepam. Published evidence of effectiveness is limited. Most trials are of small size, of short duration, and have not reported on functional outcomes. Studies have been published which suggest that badofen, tizanidine, and diazepam are all effective in reducing dinical measures of spasticity, but there is little evidence that they lead to an improvement in patient function. There is no evidence to suggest any difference in effectiveness between them. The evidence that dantrolene has any effect on spasticity is of poor quality. Diazepam and dantrolene are associated with more side effects than baclofen and tizanidine. There is evidence for the effectiveness of gabapentin in reducing spasticity and improving function in the short term, though longer-term studies are needed to establish its true value. One randomized controlled trial of threonine does not support its effectiveness.

Blood donor screening for parvovirus B19

A programme of blood donor screening for parvovirus B19 was conducted from January to May 1990. The main aim of the study was to identify a B19 positive donation that could be used as a source of viral antigen for diagnostic serology. Out of 24,000 donors tested one was positive for B19 antigen by counter current immunoelectrophoresis and over 100 ml of undiluted B19 containing material was obtained. However, much of the positive donation was incorporated in a plasma pool of 28 donations. An acid dissociation technique was used to recover B19 antigen from immune complexes formed in the plasma pool.

Characterization of measles virus strains causing SSPE: a study of 11 cases

Eleven subacute sclerosing panencephalitis (SSPE) cases diagnosed in the UK between 1965 and 2000 were investigated. The entire or partial matrix (M), hemagglutinin (H), and nucleoprotein (N) genes of measles virus (MV) were sequenced following direct RT-PCR amplification from brain tissues. All the M genes showed the characteristic biased hypermutations and a premature termination codon was detected in 5/11 M sequences. Based on the more highly conserved H and N genes observed in persistent MV studies, phylogenetic analysis showed that two of three strains from patients likely to have acquired infection in the 1950s were related to clade C (WHO designation) and one appears to be a novel genotype. Three strains from patients infected in the 1960s and 1970s were clearly related to a MV strain isolated in 1974 belonging to genotype D1. Four strains from patients infected in the 1980s clustered with genotype D7 strains. One sequence from a patient infected in 1990s was identified as genotype D6. No vaccine strains were detected although five of these patients had been previously immunized. The sequence data obtained from these historic strains do not support the view that vaccine strains are associated with SSPE and provide valuable information for further studies of MV epidemiology, evolution, and pathogenesis in SSPE.

The genomic sequence of a contemporary wild-type mumps virus strain

Vaccination has the potential to eradicate mumps, and 82 countries now include a live attenuated mumps vaccine as part of their childhood vaccination programme. Although, monotypic, genetic variants of mumps virus (MuV) have been described based on comparison of the SH gene sequences, and at least seven genotypes have been identified. We now report the entire sequence of a recently isolated wild type MuV strain, Glouc1/UK96 (Glouc1) by direct sequencing of the cDNA obtained from cell culture fluid. The genome of this recent isolate was 15384 nucleotides in length. There were 579 nucleotide differences (3.8%) and 71 amino acid differences (1.5%) between Glouc1, a genotype G strain and Ur-AM9, a genotype B strain. Other MuV strains with available sequences were also compared with this pathological strain. The sequence of the contemporary strain reported here provides a picture of the variability of MuV over its entire genome (GenBank accession no. AF280799).

A simple and sensitive DNA hybridization assay used for the routine diagnosis of human parvovirus B19 infection

A dot blot hybridization assay for parvovirus B19 diagnosis was developed by using a PCR-generated probe, digoxigenin labelling, and chemiluminescence detection. Different labelling techniques and hybridization solutions were evaluated. From this analysis a protocol was devised for routine diagnostic use. The protocol enabled 1 pg of B19 DNA to be detected. The results of applying this method to 8,369 diagnostic samples collected during 1994 and 1995 are given.

Office-based arthroscopic synovectomy of the wrist in rheumatoid arthritis

We present an office-based technique for performing arthroscopic synovectomy of the wrist in patients with rheumatoid arthritis. Intra-articular anesthesia as well as subcutaneous portal anesthesia are used. Standard portals are used in the radial carpal and midcarpal joints. Standard instrumentation is used and the synovectomy is accomplished using a motorized shaver. We performed 30 procedures in 21 patients: 15 complete synovectomies, 3 radioulnar carpal synovectomies because of only limited disease, and 12 limited synovectomies because these patients were participants in a clinical trial and required only limited synovectomy for investigational purposes. There were no complications. Office-based arthroscopic synovectomy of the wrist in patients with refractory rheumatoid arthritis can be performed safety and effectively. This technique is useful in both a clinical as well as a research setting.

Economic evaluation in chronic pain: a systematic review and de novo flexible economic model

There is unmet need in patients suffering from chronic pain, yet innovation may be impeded by the difficulty of justifying economic value in a field beset by data limitations and methodological variability. A systematic review was conducted to identify and summarise the key areas of variability and limitations in modelling approaches in the economic evaluation of treatments for chronic pain. The results of the literature review were then used to support the development of a fully flexible open-source economic model structure, designed to test structural and data assumptions and act as a reference for future modelling practice. The key model design themes identified from the systematic review included: time horizon; titration and stabilisation; number of treatment lines; choice/ordering of treatment; and the impact of parameter uncertainty (given reliance on expert opinion). Exploratory analyses using the model to compare a hypothetical novel therapy versus morphine as first-line treatments showed cost-effectiveness results to be sensitive to structural and data assumptions. Assumptions about the treatment pathway and choice of time horizon were key model drivers. Our results suggest structural model design and data assumptions may have driven previous cost-effectiveness results and ultimately decisions based on economic value. We therefore conclude that it is vital that future economic models in chronic pain are designed to be fully transparent and hope our open-source code is useful in order to aspire to a common approach to modelling pain that includes robust sensitivity analyses to test structural and parameter uncertainty.

Concentration and heritability of immunoglobulin G and natural antibody immunoglobulin M in dairy and beef colostrum along with serum total protein in their calves

Immunoglobulin (Ig) G and natural antibody (NAb) IgM are passively transferred to the neonatal calf through bovine colostrum. Maternal IgG provides pathogen- or vaccine-specific protection and comprises about 85% of colostral Ig. NAb-IgM is less abundant but provides broad and nonspecific reactivity, potentially contributing to protection against the dissemination of pathogens in the blood (septicemia) in a calf's first days of life. In the dairy and beef industries, failure of passive transfer (FPT) of colostral Ig (serum total protein [STP] <5.2 g/dL) is still a common concern. The objectives of this study were to: (1) compare colostral IgG concentrations and NAb-IgM titers between dairy and beef cows; (2) assess the effect of beef breed on colostral IgG; (3) compare passive transfer of colostral Ig in dairy and beef calves; and (4) estimate the heritability of colostral IgG and NAb-IgM. Colostrum was collected from Holstein dairy (n = 282) and crossbred beef (n = 168) cows at the University of Guelph dairy and beef research centers. Colostral IgG was quantified by radial immunodiffusion and NAb-IgM was quantified by an enzyme-linked immunosorbent assay. In dairy (n = 308) and beef (n = 169) calves, STP was estimated by digital refractometry. Beef cows had significantly greater colostral IgG (146.5 ± 9.5 standard error of the mean [SEM] g/L) than dairy cows (92.4 ± 5.2 g/L, P <0.01). Beef cows with a higher proportion of Angus ancestry had significantly lower colostral IgG (125.5 ± 5.8 g/L) than cows grouped as "Other" (142.5 ± 4.9 g/L, P = 0.02). Using the FPT cutoff, 13% of dairy and 16% of beef calves had FPT; still, beef calves had a significantly larger proportion with excellent passive transfer (STP ≥6.2 g/dL, P <0.01). The heritability of colostral IgG was 0.04 (±0.14) in dairy and 0.14 (±0.32) in beef. Colostral NAb-IgM titers in dairy (12.12 ± 0.22, log2 [reciprocal of titer]) and beef cows (12.03 ± 0.19) did not differ significantly (P = 0.71). The range of NAb-IgM titers was 9.18-14.60, equivalent to a 42-fold range in antibody concentration. The heritability of colostral NAb was 0.24 (±0.16) in dairy and 0.11 (±0.19) in beef cows. This study is the first to compare colostral NAb-IgM between dairy and beef cows. Based on the range in NAb-IgM titers and the heritability, selective breeding may improve colostrum quality and protection for neonatal calves in the early days of life.

High copper concentration reduces biofilm formation in Acidithiobacillus ferrooxidans by decreasing production of extracellular polymeric substances and its adherence to elemental sulfur

Acidithiobacillus ferrooxidans is an acidophilic bacterium able to grow in environments with high concentrations of metals. It is a chemolithoautotroph able to form biofilms on the surface of solid minerals to obtain its energy. The response of both planktonic and sessile cells of A. ferrooxidans ATCC 23270 grown in elemental sulfur and adapted to high copper concentration was analyzed by quantitative proteomics. It was found that 137 proteins varied their abundance when comparing both lifestyles. Copper effllux proteins, some subunits of the ATP synthase complex, porins, and proteins involved in cell wall modification increased their abundance in copper-adapted sessile lifestyle cells. On the other hand, planktonic copper-adapted cells showed increased levels of proteins such as: cupreredoxins involved in copper cell sequestration, some proteins related to sulfur metabolism, those involved in biosynthesis and transport of lipopolysaccharides, and in assembly of type IV pili. During copper adaptation a decreased formation of biofilms was measured as determined by epifluorescence microscopy. This was apparently due not only to a diminished number of sessile cells but also to their exopolysaccharides production. This is the first study showing that copper, a prevalent metal in biomining environments causes dispersion of A. ferrooxidans biofilms. SIGNIFICANCE: Copper is a metal frequently found in high concentrations at mining environments inhabitated by acidophilic microorganisms. Copper resistance determinants of A. ferrooxidans have been previously studied in planktonic cells. Although biofilms are recurrent in these types of environments, the effect of copper on their formation has not been studied so far. The results obtained indicate that high concentrations of copper reduce the capacity of A. ferrooxidans ATCC 23270 to form biofilms on sulfur. These findings may be relevant to consider for a bacterium widely used in copper bioleaching processes.

Immuno-phenotyping of Canadian Beef Cattle: Adaptation of the High Immune Response Methodology for Utilization in Beef Cattle

The high immune response (HIR) methodology measures the genetic performance of the adaptive immune system to identify and breed animals with balanced and robust immunity. The HIR methodology has previously been used in dairy and swine to reduce disease but has not been fully investigated in beef cattle. The first objective of the current study was to examine whether the HIR methodology as standardized for use in dairy cattle was appropriate for use in beef cattle. The second objective was to determine the earliest age for immune response phenotyping of beef calves. In this study, beef calves (n = 295) of various ages, as well as mature beef cows (n = 170) of mixed breeds, were immunized using test antigens to assess their antibody- (AMIR) and cell-mediated immune responses (CMIR). Heritability for AMIR and CMIR was estimated at 0.43 and 0.18, respectively. The HIR methodology was appropriate for use in beef cattle; beef calves as young as 2–3 wk of age were capable of mounting AMIR responses comparable with those seen historically in mature Holstein dairy cows. Three-week-old beef calves mounted CMIR responses comparable with those of Holstein cows, but 9-mo-old calves and mature beef cows had significantly higher CMIR responses than Holsteins. The HIR methodology can be used to measure both AMIR and CMIR in beef calves as young as 3 wk of age.

Genotyping of measles and mumps virus strains using amplification refractory mutation system analysis combined with enzyme immunoassay: a simple method for outbreak investigations

A simple method, based on a modification of the amplification refractory mutation system (ARMS), for genotyping outbreak strains of measles and mumps viruses and detecting these in a simple enzyme immunoassay (EIA) is described. Fifty-three measles strains circulating at the time of an outbreak in London in 2000 and 26 strains circulating at the time of a mumps outbreak in Accrington, UK, in 1999 were investigated. All strains were genotyped by direct sequencing. ARMS primers were then designed to amplify the outbreak strain. The ARMS-EIA for measles and mumps detected all 36 measles outbreak strains as genotype D6, and all 15 mumps outbreak strains as genotype F, respectively. The sensitivity and specificity of both the measles D6 and Mumps F genotype ARMS EIA was 100% compared with direct sequencing. The results show that ARMS-EIA can be used as a rapid alternative to genotyping by direct sequence analysis in outbreak situations.

Successful treatment of parvovirus B19 infection and red cell aplasia occurring after an allogeneic bone marrow transplant

Chronic parvovirus B19 infection in the immunocompromised host may cause severe anaemia secondary to failure of erythropoiesis. This has been previously documented in patients with the Acquired Immune Deficiency Syndrome (AIDS), congenital immunodeficiencies and in children with acute lymphoblastic leukaemia during maintenance chemotherapy. We describe persistent parvovirus infection in a 14-year-old boy after HLA-matched sibling allogeneic bone marrow transplantation for acute lymphoblastic leukaemia in second remission.

Septicemia caused by Capnocytophaga in a granulocytopenic patient with glossitis

A patient receiving immunosuppressive treatment for multiple myeloma became granulocytopenic, and acute glossitis developed. Blood cultures were positive for Capnocytophaga, a fastidious Gram-negative bacillus that is known to be part of the normal oral flora and a pathogen for periodontitis. The infection responded to treatment with antibiotics, including penicillin G, to which the organism was sensitive. This is one of the first reports of Capnocytophaga septicemia, and suggests that this organism may be an important pathogen in immunosuppressed patients with oral mucosal lesions.

The effects of timing of high immune response phenotyping in relation to weaning on immune responses of crossbred beef calves

Genetic selection for immune response has the potential to increase the sustainability of the beef industry by breeding cattle that are productive yet with an increased capacity to resist disease. Determining the optimal time to immunophenotype beef cattle is crucial for the accurate prediction of an animal's immune response. The objective of this study was to determine the effect of time of immunophenotyping in relation to weaning on immune responses of beef calves. Antibody- (AMIR) and cell-mediated (CMIR) immune responses were measured on 97 calves on the day of weaning (WEANING, N = 56) or 2 mo post-weaning (POST-WEANING, N = 41). Within each period of immunophenotyping, on day 0, blood was collected, and calves received a 1.0 mL intramuscular injection of type 1 and 2 test antigens. On day 14, blood was collected, and baseline skinfold thickness (SFT) was measured. Calves received an intradermal injection of 0.1 mg of the type 1 antigen suspended in 0.1 mL phosphate buffered saline (PBS) in the right tail fold, and 0.1 mL of PBS in the left. Changes in SFT at 24 h was used to indicate CMIR. To assess AMIR, the titer of type 2 antigen-specific bovine immunoglobulin G in serum from blood collected on day 14 was determined by measuring optical density (OD) using an enzyme-linked immunosorbent assay (ELISA). Among heifers, AMIR was greater for the POST-WEANING group than for the WEANING group (P < 0.01). Among steers, AMIR was not different between the POST-WEANING group and the WEANING group (P = 1.0). Therefore, the AMIR of heifers may be more negatively affected by immunophenotyping at weaning than the AMIR of steers. For steers, CMIR was greater in the POST-WEANING group than the WEANING group (P < 0.001). For heifers, CMIR was not different between the POST-WEANING group and the WEANING group (P = 0.22). The CMIR of steers may be more negatively affected by immunophenotyping at weaning than the CMIR of heifers. Calf age was not associated with AMIR or CMIR for calves phenotyped at weaning or post-weaning. The effect of sire nested within dam age was significant for CMIR for calves in the POST-WEANING group (P < 0.01), but not for calves in the WEANING group (P = 0.67). The results suggest that measuring immunocompetence at weaning may not be representative of a calf's genetic ability to mount an effective immune response, and immunophenotyping should be performed outside the weaning period.

Regulation of body temperature in Canadian beef cattle of various immune response phenotypes when the temperature humidity index is above normal

Climate change with increases in ambient temperature and humidity, affect animal life dramatically decreasing their production and reproduction potential, as well as making them more susceptible to different diseases. This leads to an increase in their core body temperature and respiration rate which in turn decreases their production, reproduction, and immune function. The High Immune Response (HIR™) technology which has been developed at the University of Guelph ranks animals using two arms of adaptive immune system to high (H), average (A), and low (L) immune responders. (H) immune responders have been reported to have fewer incidents of disease and robust immune response. (H) immune responders have been also reported to have better colostrum and milk quality making them an ideal model to examine the effects of climate change on health traits. The objective of this study was to check if (H) immune responder beef cattle are able to regulate their rectal temperature better. In this study, rectal temperatures of 36 beef cows were recorded during normal Temperature-Humidity Index (THI&lt;74) and above normal THI (THI ≥ 74) once in the morning and once in the afternoon. Results indicated that 62.5% of cows showed increases in rectal temperature in THI ≥ 74. However, mean rectal temperatures of (H) antibody-mediated immune responders did not differ significantly during THI &lt; 74 and THI ≥ 74; indicating that these high antibody responder beef cows were better able to regulate their body temperatures.

This is the first time that genetic regulation of an immune response trait has been shown to influence the response to in vivo heat stress indicating that it may be possible to select cattle with both improved health and heat tolerance.