Aphid infestations reduce monarch butterfly colonization, herbivory, and growth on ornamental milkweed

Anthropogenic disturbance is driving global biodiversity loss, including the monarch butterfly (Danaus plexippus), a dietary specialist of milkweed. In response, ornamental milkweed plantings are increasingly common in urbanized landscapes, and recent evidence indicates they have conservation value for monarch butterflies. Unfortunately, sap-feeding insect herbivores, including the oleander aphid (Aphis nerii), frequently reach high densities on plants in nursery settings and urbanized landscapes. Aphid-infested milkweed may inhibit monarch conservation efforts by reducing host plant quality and inducing plant defenses. To test this, we evaluated the effects of oleander aphid infestation on monarch oviposition, larval performance, and plant traits using tropical milkweed (Asclepias curassavica), the most common commercially available milkweed species in the southern U.S. We quantified monarch oviposition preference, larval herbivory, larval weight, and plant characteristics on aphid-free and aphid-infested milkweed. Monarch butterflies deposited three times more eggs on aphid-free versus aphid-infested milkweed. Similarly, larvae fed aphid-free milkweed consumed and weighed twice as much as larvae fed aphid-infested milkweed. Aphid-free milkweed had higher total dry leaf biomass and nitrogen content than aphid-infested milkweed. Our results indicate that oleander aphid infestations can have indirect negative impacts on urban monarch conservation efforts and highlight the need for effective Lepidoptera-friendly integrated pest management tactics for ornamental plants.

Protective Benefits of Tending Ants to a Critically Endangered Butterfly

Ants provide protection to various organisms via myrmecophilous relationships. Most notably, ants and several butterfly species are involved in mainly mutualistic interactions. Previous field studies have shown that butterfly larval survival is increased in the presence of tending ants, suggesting that ants are providing protection against insect predation or parasitism. Here, we conducted a series of timed observational trials under laboratory conditions to assess larval survival and ant protection from insect predators for a myrmecophilous lycaenid butterfly. We focused on a critically endangered butterfly, the Miami blue (Cyclargus thomasi bethunebakeri) (Comstock and Huntington) (Lepidoptera: Lycaenidae), and its most common ant associate, the Florida carpenter ant (Camponotus floridanus) (Buckley) (Hymenoptera: Formicidae), to test this assumption of ant protection. We found that ants provide significant protection to Miami blue larvae, with later instar larvae receiving a higher level of protection due to differences in tending frequencies. These results will aid in informing conservation management and future organism reintroductions for this endangered butterfly.

Climate change effects on animal ecology: butterflies and moths as a case study

Butterflies and moths (Lepidoptera) are one of the most studied, diverse, and widespread animal groups, making them an ideal model for climate change research. They are a particularly informative model for studying the effects of climate change on species ecology because they are ectotherms that thermoregulate with a suite of physiological, behavioural, and phenotypic traits. While some species have been negatively impacted by climatic disturbances, others have prospered, largely in accordance with their diversity in life-history traits. Here we take advantage of a large repertoire of studies on butterflies and moths to provide a review of the many ways in which climate change is impacting insects, animals, and ecosystems. By studying these climate-based impacts on ecological processes of Lepidoptera, we propose appropriate strategies for species conservation and habitat management broadly across animals.

Bloom evenness modulates the influence of bloom abundance on insect community structure in suburban gardens

As land use change drives global insect declines, the value of enhancing habitat in urban and suburban landscapes has become increasingly important for flower-visiting insects. In order to help identify best landscaping practices, we conducted plant surveys and insect bowl-trap surveys in 34 suburban yards for 21 months in Gainesville, FL, USA, which resulted in 274 paired days of plant and insect survey data. We assessed the impact of nearest greenspace size, distance to greenspace, yard area, plant richness, plant type, bloom abundance, bloom richness and bloom evenness on insect abundance and richness. Our samples include 34,972 insects captured, 485,827 blooms counted and 774 species of plants recorded. We found that bloom evenness had a modulating effect on bloom abundance—a more even sample of the same number of blooms would have a disproportionately greater positive impact on flower visitor richness, insect richness and insect abundance. Bloom abundance was also highly significant and positively associated with flower visitor abundance, but nearest greenspace size, distance to greenspace, plant type (native vs. non-native vs. Florida Friendly), and yard area were not found to be important factors. Plant richness was a highly significant factor, but its effect size was very small.

Uptake and toxicity of clothianidin to monarch butterflies from milkweed consumption

Recent concern for the adverse effects from neonicotinoid insecticides has centered on risk for insect pollinators in general and bees specifically. However, natural resource managers are also concerned about the risk of neonicotinoids to conservation efforts for the monarch butterfly (Danaus plexippus) and need additional data to help estimate risk for wild monarch butterflies exposed to those insecticides. In the present study, monarch butterfly larvae were exposed in the laboratory to clothianidin via contaminated milkweed plants from hatch until pupation, and the effects upon larval survival, larval growth, pupation success, and adult size were measured. Soils dosed with a granular insecticide product led to mean clothianidin concentrations of 10.8–2,193 ng/g in milkweed leaves and 5.8–58.0 ng/g in larvae. Treatment of soils also led to clothianidin concentrations of 2.6–5.1 ng/g in adult butterflies indicating potential for transfer of systemic insecticides from the soil through plants and larvae to adult butterflies. Estimated LC₅₀s for total mortality (combined mortality of larvae and pupae) and EC50 for larval growth were variable but higher than the majority of concentrations reported in the literature for clothianidin contamination of leaves.

At-Risk Butterfly Captive Propagation Programs to Enhance Life History Knowledge and Effective Ex Situ Conservation Techniques

Improving knowledge of ex situ best practices for at-risk butterflies is important for generating successful conservation and recovery program outcomes. Research on such captive populations can also yield valuable data to address key information gaps about the behavior, life history, and ecology of the target taxa. We describe a protocol for captive propagation of the federally endangered Cyclargus thomasi bethunebakeri that can be used as a model for other at-risk butterfly ex situ programs, especially those in the family Lycaenidae. We further provide a simple and straightforward protocol for recording various life history metrics that can be useful for informing ex situ methodologies as well as adapted for laboratory studies of other lepidoptera.

Phylogeography and population genetics of pine butterflies: Sky islands increase genetic divergence

The sky islands of southeastern Arizona (AZ) mark a major transition zone between tropical and temperate biota and are considered a neglected biodiversity hotspot. Dispersal ability and host plant specificity are thought to impact the history and diversity of insect populations across the sky islands. We aimed to investigate the population structure and phylogeography of two pine-feeding pierid butterflies, the pine white (Neophasia menapia) and the Mexican pine white (Neophasia terlooii), restricted to these "islands" at this transition zone. Given their dependence on pines as the larval hosts, we hypothesized that habitat connectivity affects population structure and is at least in part responsible for their allopatry. We sampled DNA from freshly collected butterflies from 17 sites in the sky islands and adjacent high-elevation habitats and sequenced these samples using ddRADSeq. Up to 15,399 SNPs were discovered and analyzed in population genetic and phylogenetic contexts with Stacks and pyRAD pipelines. Low genetic differentiation in N. menapia suggests that it is panmictic. Conversely, there is strong evidence for population structure within N. terlooii. Each sky island likely contains a population of N. terlooii, and clustering is hierarchical, with populations on proximal mountains being more related to each other. The N. menapia habitat, which is largely contiguous, facilitates panmixia, while the N. terlooii habitat, restricted to the higher elevations on each sky island, creates distinct population structure. Phylogenetic results corroborate those from population genetic analyses. The historical climate-driven fluxes in forest habitat connectivity have implications for understanding the biodiversity of fragmented habitats.

Drifting Phenologies Cause Reduced Seasonality of Butterflies in Response to Increasing Temperatures

Climate change has caused many ecological changes around the world. Altered phenology is among the most commonly observed effects of climate change, and the list of species interactions affected by altered phenology is growing. Although many studies on altered phenology focus on single species or on pairwise species interactions, most ecological communities are comprised of numerous, ecologically similar species within trophic groups. Using a 12-year butterfly monitoring citizen science data set, we aimed to assess the degree to which butterfly communities may be changing over time. Specifically, we wanted to assess the degree to which phenological sensitivities to temperature could affect temporal overlap among species within communities, independent of changes in abundance, species richness, and evenness. We found that warming winter temperatures may be associated with some butterfly species making use of the coldest months of the year to fly as adults, thus changing temporal co-occurrence with other butterfly species. Our results suggest that changing temperatures could cause immediate restructuring of communities without requiring changes in overall abundance or diversity. Such changes could have fitness consequences for individuals within trophic levels by altering competition for resources, as well as indirect effects mediated by species interactions across trophic levels.

Managed and Wild Bee Flower Visitors and Their Potential Contribution to Pollination Services of Low-Chill Highbush Blueberry (Vaccinium corymbosum L.; Ericales: Ericaceae)

Highbush blueberry (Vaccinium corymbosum L.; Ericales: Ericaceae) is an important crop grown throughout the eastern United States and Canada. Cross-pollination by insects greatly enhances pollination and fruit set in highbush blueberry. In Florida, low-chill cultivars that flower during the winter when most bees are dormant are used, thus, making it difficult to utilize and depend on unmanaged bees. We investigated flower visitation rates by managed and wild bees and the subsequent berry formation, berry weight, and number of seeds/berry in highbush blueberry fields in north-central Florida. Additionally, we tested three pollinator treatments: 1) pollinator-excluded flowers, 2) open-pollinated treatments that were available to managed and wild bees, and 3) flowers that were hand pollinated. Overall, we found seven native bee species that contribute to highbush blueberry pollination in Florida, but managed honey bees and bumble bees were the main flower visitors. Additionally, 14.5 times more blueberries formed in the open treatments than in the pollinator exclusion treatments, thus illustrating the economic impact bees have on blueberry pollination. Most of the wild bees observed visiting blueberry flowers were ground-nesting species that need uncultivated areas for nesting sites. Therefore, leaving field edges uncultivated and some undisturbed habitat may increase native bee numbers within blueberry farms over time.

Behavioral Evidence for Host Transitions in Plant, Plant Parasite, and Insect Interactions

Specialized herbivorous insects have the ability to transition between host plant taxa, and considering the co-evolutionary history between plants and the organisms utilizing them is important to understanding plant insect interactions. We investigated the role of a pine tree parasite, dwarf mistletoe (Arceuthobium spp.) M. Bieb. Santalales: Viscaceae, in mediating interactions between Neophasia (Lepidoptera: Pieridae) butterflies and pine trees, the butterflies' larval hosts. Mistletoe is considered the butterflies' ancestral host, and the evolutionary transition to pine may have occurred recently. In Arizona, United States, we studied six sites in pine forest habitats: three in Neophasia menapia (Felder and R. Felder, 1859) habitat and three in Neophasia terlooii Behr, 1869 habitat. Each site contained six stands of trees that varied in mistletoe infection severity. Butterfly behavior was observed and ranked at each stand. Volatile compounds were collected from trees at each site and analyzed using gas chromatography-mass spectroscopy. Female butterflies landed on or patrolled around pine trees (i.e., interacted) more than males, and N. terlooii interacted more with pine trees than N. menapia. Both butterfly species interacted more with tree stands harboring greater mistletoe infection, and N. terlooii interacted more with heavily infected tree stands than did N. menapia. The influence of mistletoe on Neophasia behavior may be mediated by differences in tree volatiles resulting from mistletoe infection. Volatile profiles significantly differed between infected and uninfected pine trees. The role of mistletoe in mediating butterfly interactions with pines has implications for conservation biology and forest management, and highlights the importance of understanding an organism's niche in an evolutionary context.

Differences in winter cold hardiness reflect the geographic range disjunction of Neophasia menapia and Neophasia terlooii (Lepidoptera: Pieridae)

Predicting how rapid climate change will affect terrestrial biota depends on a thorough understanding of an organism's biology and evolutionary history. Organisms at their range boundaries are particularly sensitive to climate change. As predominantly terrestrial poikilotherms, insects are often geographically limited by extremes in ambient temperatures. We compared the cold hardiness strategies of two geographically widespread butterflies, the pine white, Neophasia menapia, and the Mexican pine white, N. terlooii (Lepidoptera: Pieridae), at the near-contact zone of their range boundaries. Eggs are laid on pine needles and are exposed to harsh winter conditions. Eggs were collected from wild-caught butterflies, and we determined the supercooling point (SCP) and lower lethal temperature (LLT₅₀) of overwintering eggs. The SCP of Neophasia menapia eggs (-29.0 ± 0.6 °C) was significantly lower than that of N. terlooii eggs (-21.8 ± 0.7 °C). Both species were freeze-intolerant and capable of surviving down to their respective SCPs (LLT₅₀ of N. menapia between -30 and -31 °C, N. terlooii between -20 and -21 °C). Cold exposure time did not affect the survival of N. menapia, but N. terlooii experienced somewhat greater mortality at sub-freezing temperatures during longer exposures. Our results, coupled with an analysis of microclimate data, indicate that colder winters in northern Arizona may contribute to the northern range limit for N. terlooii. Furthermore, careful analysis of historical weather data indicates that mortality from freezing is unlikely in southern Arizona but possible in northern Arizona. Movements of Neophasia range boundaries could be monitored as potential biological responses to climate change.

Fruit Set and Single Visit Stigma Pollen Deposition by Managed Bumble Bees and Wild Bees in Citrullus lanatus (Cucurbitales: Cucurbitaceae)

Pollinators provide essential services for watermelon, Citrullus lanatus (Thunb.; Cucurbitales: Cucurbitaceae). Managed bumble bees, Bombus impatiens (Cresson; Hymenoptera: Apidae), have been shown to be a useful watermelon pollinator in some areas. However, the exact contribution bumble bees make to watermelon pollination and how their contribution compares to that of other bees is unclear. We used large cages (5.4 × 2.5 × 2.4 m) to confine bumble bee hives to watermelon plants and compared fruit set in those cages to cages containing watermelons but no pollinators, and to open areas of field next to cages (allows all pollinators). We also collected data on single visit pollen deposition onto watermelon stigmas by managed bumble bees, honey bees, and wild bees. Overall, more fruit formed within the open cages than in cages of the other two treatment groups. B. impatiens and Melissodes spp. deposited the most pollen onto watermelon stigmas per visit, but all bee species observed visiting watermelon flowers were capable of depositing ample pollen to watermelon stigmas. Although B. impatiens did deposit large quantities of pollen to stigmas, they were not common within the field (i.e., outside the cages) as they were readily drawn to flowering plants outside of the watermelon field. Overall, bumble bees can successfully pollinate watermelon, but may be useful in greenhouses or high tunnels where watermelon flowers have no competition from other flowering plants that could draw bumble bees away from watermelon.

Trap Nesting Wasps and Bees in Agriculture: A Comparison of Sown Wildflower and Fallow Plots in Florida

Wildflower strip plantings in intensive agricultural systems have become a widespread tool for promoting pollination services and biological conservation because of their use by wasps and bees. Many of the trap-nesting wasps are important predators of common crop pests, and cavity-nesting bees that utilize trap-nests are important pollinators for native plants and many crops. The impact of wildflower strips on the nesting frequency of trap-nesting wasps or bees within localized areas has not been thoroughly investigated. Trap-nests made of bamboo reeds (Bambusa sp.) were placed adjacent to eight 0.1 ha wildflower plots and paired fallow areas (control plots) to determine if wildflower strips encourage the nesting of wasps and bees. From August 2014 to November 2015, occupied reeds were gathered and adults were collected as they emerged from the trap-nests. Treatment (wildflower or fallow plots) did not impact the number of occupied reeds or species richness of trap-nesting wasps using the occupied reeds. The wasps Pachodynerus erynnis, Euodynerus megaera, Parancistrocerus pedestris, and Isodontia spp. were the most common trap-nesting species collected. Less than 2% of the occupied reeds contained bees, and all were from the genus Megachile. The nesting wasp and bee species demonstrated preferences for reeds with certain inside diameters (IDs). The narrow range of ID preferences exhibited by each bee/wasp may provide opportunities to take advantage of their natural histories for biological control and/or pollination purposes.

Jamaica's Critically Endangered Butterfly: A Review of the Biology and Conservation Status of the Homerus Swallowtail (Papilio (Pterourus) homerus Fabricius)

The Homerus swallowtail, Papilio (Pterourus) homerus Fabricius, is listed as an endangered species and is endemic to the Caribbean island of Jamaica. The largest butterfly in the Western Hemisphere, P. homerus once inhabited seven of Jamaica's 14 parishes and consisted of at least three populations; however, now only two stronghold populations remain, a western population in the rugged Cockpit Country and an eastern population in the Blue and John Crow Mountains. Despite numerous studies of its life history, much about the population biology, including estimates of total numbers of individuals in each population, remains unknown. In addition, a breeding program is needed to establish an experimental population, which could be used to augment wild populations and ensure the continued survival of the species. Here, we present a review of the biology of P. homerus and recommendations for a conservation plan.

Managed Bumble Bees (Bombus impatiens) (Hymenoptera: Apidae) Caged With Blueberry Bushes at High Density Did Not Increase Fruit Set or Fruit Weight Compared to Open Pollination

Highbush blueberry (Vaccinium corymbosum L.) is an important crop grown throughout Florida. Currently, most blueberry growers use honey bees (Apis mellifera L.) to provide pollination services for highbush blueberries even though bumble bees (Bombus spp.) have been shown to be more efficient at pollinating blueberries on a per bee basis. In general, contribution of bumble bees to the pollination of commercial highbush blueberries in Florida is unknown. Herein, we determined if managed bumble bees could contribute to highbush blueberry pollination. There were four treatments in this study: two treatments of caged commercial bumble bee (Bombus impatiens Cresson) colonies (low and high weight hives), a treatment excluding all pollinators, and a final treatment which allowed all pollinators (managed and wild pollinators) in the area have access to the plot. All treatments were located within a highbush blueberry field containing two cultivars of blooming plants, 'Emerald' and 'Millennia', with each cage containing 16 mature blueberry plants. We gathered data on fruit set, berry weight, and number of seeds produced per berry. When pollinators were excluded, fruit set was significantly lower in both cultivars (<8%) compared to that in all of the other treatments (>58%). Berry weight was not significantly different among the treatments, and the number of seeds per berry did not show a clear response. This study emphasizes the importance of bumble bees as an effective pollinator of blueberries and the potential beneficial implications of the addition of bumble bees in commercial blueberry greenhouses or high tunnels.

Can butterflies evade fire? Pupa location and heat tolerance in fire prone habitats of Florida

Butterflies such as the atala hairstreak, Eumaeus atala Poey, and the frosted elfin, Callophrys irus Godart, are restricted to frequently disturbed habitats where their larval host plants occur. Pupae of these butterflies are noted to reside at the base of host plants or in the leaf litter and soil, which may allow them to escape direct mortality by fire, a prominent disturbance in many areas they inhabit. The capacity of these species to cope with fire is a critical consideration for land management and conservation strategies in the locations where they are found. Survival of E. atala pupae in relation to temperature and duration of heat pulse was tested using controlled water bath experiments and a series of prescribed fire field experiments. Survival of E. atala pupae was correlated to peak temperature and heat exposure in both laboratory and field trials. In addition, E. atala survival following field trials was correlated to depth of burial; complete mortality was observed for pupae at the soil surface. Fifty percent of E. atala survived the heat generated by prescribed fire when experimentally placed at depths ≥ 1.75cm, suggesting that pupation of butterflies in the soil at depth can protect from fatal temperatures caused by fire. For a species such as E. atala that pupates above ground, a population reduction from a burn event is a significant loss, and so decreasing the impact of prescribed fire on populations is critical.

Using museum specimens to assess historical distribution and genetic diversity in an endangered butterfly

The Miami blue butterfly,Cyclargus thomasi bethunebakeri, is a state-endangered taxon in Florida and a candidate for federal listing. This once common butterfly saw a dramatic decline in population number and abundance in the 1970s and 1980s, but significant collections of individuals prior to this decline are deposited in natural history museums. Using museum specimens, we quantified the genetic diversity in a historical population present in Key Largo, Florida in 1940, 1960, and 1980. Genetic diversity was consistently high within this historical population, but diversity was observed to decrease over the decades sampled. A comparison of historical diversity from the Key Largo population with the extant populations on Bahia Honda State Park (BHSP) and Key West National Wildlife Refuge (KWNWR) revealed differences in allelic frequencies, but only minor differences in the overall number of alleles. The historical distribution of butterflies throughout the Florida Keys further suggests a metapopulation structure. This structure involved partially-isolated populations ofC. t. bethunebakerithat were loosely connected via gene flow and that underwent localized extinction and colonization events along the chain of suitable habitat in the Florida Keys. It appears that a “mini-metapopulation” currently exists on BHSP and KWNWR; structures that are similar to the historical metapopulation structure and distribution of populations on a larger scale. Knowledge of historical distribution helps to plan future reintroduction events with captive-bred butterflies. Additional populations of butterflies may represent undiscovered genetic diversity that, if appropriate, may be further incorporated into captive-breeding efforts.

Aquatic respiration as a potential survival mechanism of Brephidium pseudofea (Lepidoptera: Lycaenidae) larvae to intertidal environments

The eastern pygmy blue, Brephidium pseudofea (Morrison) (Lepidoptera: Lycaenidae: Polyommatinae), inhabits intertidal environments that are periodically flooded. The immature stages are subject to salt or brackish water inundation during this time and therefore must endure many stressors, including respiratory limitation and salt exposure. Our goal was to investigate possible mechanisms used by the larval stages of B. pseudofea to endure periodic tidal inundation by using physiological and morphological analyses in comparison with several species of terrestrial lepidopteran larvae. A review of tidal charts showed that the immature stages of B. pseudofea would be prone to complete inundation two to five times per month during the summer months (May to August) and partial submersion for up to 20 d per month during the rest of the year. Larvae of several terrestrial lepidopteran species studied consumed oxygen under water for a limited period, but B. pseudofea demonstrated substantially higher oxygen consumption. Light microscopy of B. pseudofea larvae revealed small air pockets in and around the spiracles when submerged in tap water; these air pockets disappeared when exposed to detergent solution. The resulting air pockets may function as a diffusion layer for oxygen to be absorbed from the surrounding water or may act in conjunction with trans-cuticular gas exchange to meet the larva's respiratory needs. Morphological examination by scanning electron microscopy showed that B. psudofea larvae have distinctively small, clavate setae that appear insufficient to effectively support a functional plastron.

Aerial ultra-low-volume application of naled: impact on nontarget imperiled butterfly larvae (Cyclargus thomasi bethunebakeri) and efficacy against adult mosquitoes (Aedes taeniorhynchus)

We assessed the exposure and acute toxicity of naled, applied aerially as an ultra-low-volume spray for mosquito control, on late instar larvae of the Miami blue (Cyclargus thomasi bethunebakeri) (Comstock and Huntington 1943) (Lepidoptera: Lycaenidae), an imperiled South Florida butterfly. We concurrently evaluated the control efficacy against caged adult female salt-marsh mosquitoes (Aedes taeniorhynchus) (Wiedemann 1821) (Diptera: Culicidae). This 3-yr study was conducted in north Key Largo (Monroe County, FL) beginning in 2006. The field trials incorporated 15 sampling stations: nine in the target spray zone, three in the spray drift zone at varying distances from the target zone, and three in the control zone not subjected to naled spray drift. A total of six field spray trials were completed, three at an altitude of 30.5 m (100 feet), and three at 45.7 m (150 feet). For all trials, the ultra-low-volume application of Trumpet EC insecticide (78% naled) at a rate of 54.8 ml/ha (0.75 fl. oz/acre) was effective in killing caged adult mosquitoes in the target zone. Butterfly larvae survival was significantly reduced in the spray zone compared with drift and control zones. Analysis of insecticide residue data revealed that the mortality of the late instar butterfly larvae was a result of exposure to excess residues of naled. Additional research is needed to determine mitigation strategies that can limit exposure of sensitive butterflies to naled while maintaining mosquito control efficacy.

Genetic estimates of contemporary effective population size in an endangered butterfly indicate a possible role for genetic compensation

The effective population size (N e ) is a critical evolutionary and conservation parameter that can indicate the adaptive potential of populations. Robust estimates of N e of endangered taxa have been previously hampered by estimators that are sensitive to sample size. We estimated N e on two remaining populations of the endangered Miami blue butterfly, a formerly widespread taxon in Florida. Our goal was to determine the consistency of various temporal and point estimators on inferring N e and to determine the utility of this information for understanding the role of genetic stochasticity. We found that recently developed 'unbiased estimators' generally performed better than some older methods in that the former had more realistic N e estimates and were more consistent with what is known about adult population size. Overall, N e /N ratios based on census point counts were high. We suggest that this pattern may reflect genetic compensation caused by reduced reproductive variance due to breeding population size not being limited by resources. Assuming N e and N are not heavily biased, it appears that the lack of gene flow between distant populations may be a greater genetic threat in the short term than the loss of heterozygosity due to inbreeding.

Host plant selection, larval survival, and reproductive phenology in Megathymus yuccae (Lepidoptera: Hesperiidae)

Our primary objective in this study was to determine the plant level and environmental factors that affect oviposition choice and subsequent offspring survival in Megathymus yuccae (Boisduval and Leconte) on its host plant, Yucca filamentosa L. A preliminary survey suggested that the frequency of pupal eclosion tent presence increased only with host plant height. In an expanded survey conducted during the adult flight period the following spring, we found that plant height increased the probability of oviposition, whereas the density of herbaceous stems and fire damage decreased the probability of egg presence. Similarly, the number of eggs on occupied plants increased with plant height and decreased with fire damage. When we surveyed the plants from the spring 2008 sampling the following winter to determine presence of late-instar larvae or pupae, we found that the probability that at least one larva survived on previously occupied plants decreased with the density of herbaceous stems. These results collectively suggest that larger, unburned Y. filamentosa individuals and those in relatively open areas are more attractive as host plants for oviposition and that larval performance is generally, but not exclusively, consistent with female preference in this system.

Human T-cell lymphotropic virus type 1-associated myelopathy, Sjögren syndrome, and lymphocytic pneumonitis

OBJECTIVE

To describe the first case of human T-cell lymphotropic virus type 1 (HTLV-1)-associated myelopathy, Sjögren syndrome, and lymphocytic pneumonitis in a nonendemic area.

BACKGROUND

Retroviruses are implicated in the pathogenesis of autoimmune diseases, including Sjögren syndrome. Asymptomatic lymphocytic pneumonitis is prevalent in HTLV-1-associated myelopathy. There are 7 case reports with the combination of HTLV-1-associated myelopathy, Sjögren syndrome, and lymphocytic pneumonitis, all of them in endemic areas for HTLV-1.

DESIGN

Case report and literature review.

RESULTS

A 40-year-old Creole woman from New Orleans, La, presented with progressive spastic paraparesis and exertional dyspnea. Review of systems revealed chronic complaints consistent with sicca syndrome. She was found to have HTLV-1-associated myelopathy by polymerase chain reaction in the cerebrospinal fluid. Increased levels of SSA, positive results on a Schirmer test, and the findings of biopsy of the minor salivary gland were consistent with Sjögren syndrome. A lung biopsy specimen showed marked lymphocytic infiltration.

CONCLUSIONS

The present case raises questions about the role of HTLV-1 in the development of autoimmunity. It also happens to be a unique occurrence in a nonendemic area.

Tenidap in patients with rheumatoid arthritis. A 4-week, placebo-controlled study

The present double-blind, placebo-controlled study was conducted to compare the safety and efficacy of tenidap in patients with rheumatoid arthritis (RA). Patients with flare of active RA following NSAID withdrawal were randomized to receive either placebo (n = 67) or tenidap (n = 131; 40-200 mg/day). The mean changes from baseline in efficacy and biochemical variables were compared between treatment groups at endpoint (4 weeks). The improvements in four of the five primary efficacy variables were significantly greater in the tenidap group compared with the placebo group (p < 0.01). Tenidap was also associated with an 18% reduction in erythrocyte sedimentation rate (ESR) and a marked, 51%, reduction in serum C-reactive protein (CRP) level, both of which were significantly greater than the changes in the placebo group (p < 0.05). The percentage of patients who discontinued because of side effects was the same in both groups (3%). In conclusion, tenidap 40-200 mg/day was effective and well tolerated in the treatment of patients with RA for 4 weeks.

Effect of ibuprofen use on muscle soreness, damage, and performance: a preliminary investigation

Twenty subjects were randomly assigned to: 1) prophylactic ibuprofen (N = 5) [400 mg TID initiated 4 h before collection of baseline data and strenuous eccentric exercise bout], 2) therapeutic ibuprofen (N = 5) [400 mg TID initiated 24 h after baseline], 3) placebo (N = 5), or 4) control (N = 5). Muscle soreness perception, plasma creatine kinase, knee extensor torque, and EMG of the quadriceps were evaluated at baseline, 24, and 48 h. The prophylactic ibuprofen group had between 40 and 50% less muscle soreness perception and significantly less decline in isometric, concentric, and eccentric torque at 24 h compared with the other three groups (P < 0.05). At 48 h both prophylactic and therapeutic ibuprofen had significantly less muscle soreness perception and decline in torque than the placebo and control groups (P < 0.05). There was no difference between the amount of muscle damage between the four groups at 24 and 48 h. Vastus medialis and lateralis EMG magnitude decreased across time. Vastus lateralis EMG magnitude had significantly less decline from baseline for prophylactic ibuprofen compared with the other three treatments at 24 h, while both prophylactic and therapeutic ibuprofen had significantly less decline at 48 h. These data indicate that a prophylactic dosage of ibuprofen does not prevent CK release from muscle, but does decrease muscle soreness perception and may assist in restoring muscle function.

Giant-cell arteritis in the southern United States. An 11-year retrospective study from the Texas Gulf Coast

Giant-cell arteritis (GCA) and polymyalgia rheumatica are systemic disorders that reportedly affect primarily white women older than age 50 years. We conducted an 11-year chart review to determine the relative occurrence and pattern of demographic involvement of GCA in the Gulf Coast region of the United States. Of 101,239 computer-coded entries for individual patients aged 40 years or older, 60 charts listed GCA as a differential diagnosis. Twenty-seven patients had temporal GCA; 21 temporal artery biopsy specimens were identified. Two patients had associated systemic GCA (one with aortitis). A striking finding was that 13 of the 27 patients were black women (about 50% of the entire study population). The group with GCA and polymyalgia rheumatica (17 patients) had a significantly higher mean erythrocyte sedimentation rate than the group with "pure" GCA. Jaw claudication and blindness were rare. We concluded that temporal GCA seems relatively uncommon in the Gulf Coast region and in the southern United States as a whole. Furthermore, GCA seems rare in Hispanics (only one patient identified). Nonetheless, this is the first report to document a proportionally high occurrence of GCA in black patients in this part of the country.

Ultrastructural and immunohistochemical evidence for release of eosinophilic granules in vivo: cytotoxic potential in chronic eosinophilic pneumonia

We studied a patient with relapsing idiopathic chronic eosinophilic pneumonia. Each one of four attacks observed during a 4-year period was characterized by dyspnea, wheezing, peripheral blood eosinophilia, elevated serum IgE levels, and pulmonary infiltrates. Glucocorticoid therapy caused prompt resolution of symptoms and disappearance of blood eosinophilia and pulmonary shadowing. Electron microscopy and tissue immunofluorescence studies for major basic protein documented extensive eosinophil degranulation and the presence of free granules within the pulmonary microvasculature. In addition, exfoliation of the alveolar lining cell was observed in association with a clustering of free intact and disintegrating extracellular eosinophil granules against a denuded basement membrane. These findings suggest a cytotoxic potential of the eosinophil at the level of the pulmonary parenchyma in a case of idiopathic chronic eosinophilic pneumonia.

Thalidomide effects in Behçet's syndrome and pustular vasculitis

Pustular vasculitis is a new disease concept that links cutaneous, and possibly systemic, aspects of Behçet's, bowel bypass, bowel-associated dermatosis-arthritis, and disseminated gonorrhea syndromes. The pathomechanism of pustular vasculitic lesion generation may relate to circulating immune complex (CIC)-mediated vessel damage and serum enhancement of neutrophil migration. Thalidomide, an oral pharmaceutical available on strict protocol, has therapeutic effects based on proposed modulation of CIC- and neutrophil-mediated cytotoxicity. Thalidomide therapy was started for four patients with significant morbidity from Behçet's syndrome and for one patient with bowel-associated dermatosis-arthritis syndrome. Clinical benefit was dramatic in all patients who completed sequential four-week "on" and "off" thalidomide therapeutic cycles. In three of four patients, in vivo testing for CIC after histamine injection immunopathology converted from positive (immunoreactant deposition in dermal vasculature [four hours after histamine] and CIC-mediated vasculitis [24 hours after histamine]) to negative during therapy. No effects were noted on neutrophil migration or on the LFA-1/Mac-1/p150,95 family of glycoproteins associated with neutrophil adherence as assessed qualitatively by tritium labelling of neutrophil cell surfaces. In this small patient group, thalidomide was a clinically effective, safe (with rigid monitoring) therapy whose mechanism of action may relate more to inhibitory effects on CIC-induced vasculitis than to effects on neutrophil-mediated cytotoxicity.

Mechanism-oriented assessment of isotretinoin in chronic or subacute cutaneous lupus erythematosus

Eight of ten patients with chronic or subacute cutaneous lupus erythematosus completed 16 weeks of oral isotretinoin therapy (80 mg/day). All eight patients noted an excellent clinical response without significant side effects. (Two patients did not return to initial two-week follow-up.) Peripheral blood B- and T-cell counts were unaffected by therapy. Therapy was associated with resolution of routine histopathologic abnormalities, conversion of abnormal lesional direct immunofluorescence microscopy to normal, normalization of the epidermis on electron microscopy, and reduction of all T cells near the dermoepidermal junction without change in ratio of T-helper/inducer cells to T-suppressor/cytotoxic cells. Isotretinoin is a clinically effective short-term therapy for chronic or possibly for subacute cutaneous lupus erythematosus. The primary mechanism of action remains unestablished.

Coexistent systemic lupus erythematosus and tophaceous gout

Only seven patients with coexistent gout and systemic lupus erythematosus have been reported in the English-language literature. We describe an eighth case, which is the first, to our knowledge, in the dermatologic literature. The patient met four of the eleven new American Rheumatism Association criteria for the diagnosis of systemic lupus erythematosus, and clinical, laboratory, roentgenographic, and histologic assessments confirmed the diagnosis of gout.

Polymyositis presenting with panniculitis

Although microscopic areas of panniculitis may frequently occur in patients with dermatomyositis and polymyositis, large, clinically obvious plaques are unusual. We report a patient with polymyositis who initially had panniculitis of the thigh. Histologically, a lobular lymphoplasmacytic infiltrate was present in the subcutis.

Complex aphthosis: a forme fruste of Behçet's syndrome?

The evaluation of the rare patient who presents with oral and genital aphthae or almost constant, multiple (greater than 3) oral aphthae, but no systemic signs or symptoms (i.e., complex aphthosis), is difficult because no laboratory test is available to exclude Behçet's syndrome. Six patients with complex aphthosis were evaluated. In addition, patients with simple aphthosis, those with seronegative arthritis, and normal controls were assessed for circulating immune complexes (CIC) by in vitro and in vivo assays and for neutrophil migration by subagarose methods, since these tests have given significant results in patients with Behçet's syndrome. Patient 1, with complex aphthosis, had Raji cell evidence for CIC (51.2 mg aggregated human gamma globulin Eq/ml), C1q, and C3 in dermal blood vessels 4 hours post intradermal histamine injection and had a Sweet's syndrome-like vasculitis 24 hours post histamine injection. In addition, her serum enhanced the migration of patient neutrophils (3.6 +/- 0.6 to 4.6 +/- 0.5; N = 6, p less than or equal to 0.01). All other test and control patients had negative or normal CIC and neutrophil migration determinations. Sixteen-month clinical follow-up has confirmed that Patient 1, but not Patients 2 to 6, has developed overt manifestations of Behçet's syndrome.

Intravenous immune globulin therapy. Treatment of a patient with severe immunodeficiency, chronic malabsorption, and fulminant septicemia

Biweekly 200 mg/kg infusions of immune globulin (Gamimune) were given to a 46-year-old woman with severe common variable immunodeficiency, bronchiectasis, and chronic diarrhea with malabsorption. Failure to achieve therapeutically effective serum IgG concentrations in the face of fulminant sepsis was accompanied by a shortened serum IgG half-life of 10.6 days. Currently recommended doses of 200 mg/kg may prove inadequate in very ill patients with sepsis and malabsorption.

Evaluation of immune-enhancing effects of ibuprofen in an immunodeficiency model

Three children and one adult with chronic mucocutaneous candidosis with documented deficient cellular immunity to Candida antigen were evaluated as a model to study the specific cellular immune-enhancing potential of the prostaglandin synthetase inhibitor ibuprofen. Oral ibuprofen failed to have any consistent effect during sequential 4-week on and off cycles on the following parameters: delayed hypersensitivity skin testing; lymphocyte transformation to Candida antigen; T-cell subsets as determined by monoclonal antibody techniques; production of human immune interferon in response to staphylococcal enterotoxin A (SEA). Two patients showed a trend toward enhanced lymphocyte transformation to PHA while taking ibuprofen. In two patients who were studied 8-10 weeks after discontinuation of oral ketoconazole therapy, clinical recurrence of CMC was not prevented by oral ibuprofen therapy.

Immunologic safety of ibuprofen in rheumatoid arthritis: preliminary evidence

Some evidence indicates that ibuprofen and other prostaglandin synthetase inhibitors may have the potential for cellular immune enhancement in addition to their anti-inflammatory activity. If this is true, treatment of rheumatoid arthritis, a disorder of presumed autoimmune pathogenesis, would present a dilemma. These agents are widely used in rheumatoid arthritis for their anti-inflammatory effects. If they are found to enhance cellular immune function, however, the disease might be stimulated over the long term, rather than suppressed. Preliminary evidence from four patients with rheumatoid arthritis show that oral ibuprofen had no significant immunologic effect during sequential "on" and "off" cycles, as assessed by the following measures: delayed hypersensitivity skin testing; lymphocyte transformation to mitogen (phytohemagglutinin) or specific antigen (Candida albicans); T-cell subsets, as determined by monoclonal antibody techniques; or production of the lymphokine, human immune interferon, in response to phytohemagglutinin or to staphylococcal enterotoxin A. Early evidence, therefore, suggests that oral ibuprofen therapy may be 'immunologically safe' in patients with rheumatoid arthritis, but investigations of large series of patients also assessing local immune reaction in diseased joints may be necessary for confirmation.

Antinuclear antibodies in the serum of normal pregnant women: a prospective study

A prospective study was performed to determine the incidence of antinuclear antibodies in 214 normal pregnant women and in 50 age-matched controls. Serum samples of 23 pregnant women (10.7%) yielded positive results (1 + or more at a dilution of 1:20) in contrast with only one sample (2%) in the control group (p less than 0.05). Of the pregnant women found to be positive, five (9.2%) were in the second trimester, and 18 (13.4%) were in the last trimester. Only two also had positive anti-DNA antibodies. A review of their hospital records disclosed no reason to suspect systemic lupus erythematosus or other rheumatologic diseases nor any significant increase in neonatal morbidity of their infants. We conclude that the incidence of antinuclear antibodies in pregnant women is significantly higher than in nonpregnant women and that the finding probably does not correlate with any adverse clinical effect.

Bowel-associated dermatosis-arthritis syndrome. Immune complex-mediated vessel damage and increased neutrophil migration

In a recent report we described a syndrome, identical to bowel-bypass syndrome, that occurred in four patients who had not had bypass surgery. Herein, circulating immune complexes (CICs) and neutrophil migration are evaluated in three of those four patients to test the hypothesis that the cutaneous lesions might have resulted from interaction between immune complex-mediated vessel damage and increased neutrophil migration. In vitro assays indicated that CICs were present in one of two patients and "histamine trap" test evidence for CICs was present in both patients tested. Although serum from the three patients appeared to increase neutrophil movement, statistically significant increases were not observed when data were pooled in this small study group. Preliminary results suggest that immune complex-mediated vessel damage, followed by extensive accumulation of neutrophils, may cause the pustular vasculitis in the bowel-associated dermatosis-arthritis syndrome.

Behçet's syndrome: immune regulation, circulating immune complexes, neutrophil migration, and colchicine therapy

Immune regulatory dysfunction, circulating immune complexes (CIC), and polymorphonuclear (PMN) cell migration were investigated in patients with Behçet's syndrome. Six patients meeting rigorous clinical criteria were evaluated. Only one patient showed evidence of immune regulatory dysfunction (increased T4/T8 ratio). Although C1q binding and Raji cell assays for CIC yielded positive results in only one of five patients, all five patients had in vivo "histamine trap test" evidence of CIC (all controls had normal results). Sera from all Behçet's syndrome patients increased migration of neutrophils to zymosan-activated serum. Colchicine therapy abolished the enhancing effect of the patient's sera on movement of PMN cells from patients and controls. An immune complex-mediated injury that is followed by an excessive accumulation of PMN cells may lead to the cutaneous lesions and other lesions in Behçet's syndrome. Further evaluation of colchicine therapy is warranted on the basis of these studies.

Sjögren's syndrome presenting with hypereosinophilia, lymphopenia and circulating immune complexes

Although mild peripheral eosinophilia is a common finding in Sjögren's syndrome (SS), severe eosinophilia with a clinical picture simulating hypereosinophilic syndrome is extremely rare. We report a 24 year old male with SS presenting with swelling of the parotid glands, redness and irritation of the eyes, polyarthralgias and polyarthritis, weight loss, exertional dyspnea, malaise, erythematous and urticarial skin lesions and enlarged lymph nodes. Laboratory tests showed hypereosinophilia (34%, total 3800/mm3), lymphopenia (2%, total 220/mm3), a positive RA factor (1:2560) and decreased C3 and C4. Biopsy of an enlarged submaxillary gland was consistent with SS. A Schirmer test showed decreased tear production. Salivary glands showed a marked decrease in uptake of radioactive (Tc99) dye. Circulating immune complexes (CIC) were markedly elevated by both C1q binding and Raji cell assays. T-cell subsets showed OKT3 = 63%, OKT4 = 32% and OKT8 = 16%. "Histamine trap" in vivo test for CIC revealed fluorescence in upper dermal blood vessels with IgM, C1q, C3 and fibrin. Biopsies of the liver, bone marrow and skin revealed eosinophilic infiltration. A notable response to therapy with high doses of corticosteroids was seen with recurrence of symptoms and laboratory abnormalities after the therapy was stopped. In conclusion, we present a case of SS which is remarkable for the age and sex of the patient, extreme hypereosinophilia, marked lymphopenia, and CIC.

Human T-cell subset changes during culture

When human peripheral blood lymphocytes (PBL) are cultured with either concanavalin A (Con A)-treated or control autologous T lymphocytes, the mitogenic responses of the PBL co-cultured with Con A-treated cells are much lower. We have investigated the cell surface receptor changes during culture of T cells with and without mitogen in an attempt to explain this differential regulatory phenomenon. We present data here which show that human T cells cultured in complete medium alone gain helper cells with time. Con A-treated T cells are known to lose helper cells during culture. Erythrocyte rosette-purified T cells were cultured with or without Con A for 84 h and the numbers of cells with receptors for the Fc regions of either IgM (T mu) or IgG (T gamma) were enumerated daily. T mu cells have been associated with helper activity while T gamma cells have predominantly suppressor activity. Treatment with 10 micrograms/ml of Con A decreased T mu by approximately 50%. Untreated cells, however, showed significant increases in T mu (44 +/- 30.5% in twelve individuals). The great variance in T mu increases is due to the fact that individuals having higher initial T mu values showed smaller increases. These changes probably represent the gain or loss of receptors because total cell numbers did not change. There was no significant change in the number of T gamma cells in either control or Con A-treated cultures during the same 84 h period. In co-culture experiments in which the responses of fresh autologous PBL were determined, 60-h control T-cell cultures enhanced the mitogen responses of the fresh cells.(ABSTRACT TRUNCATED AT 250 WORDS)

Proportional and functional studies of the infiltrating lymphocytes in the parotid gland of Sjögren's syndrome associated with rheumatoid arthritis

Lymphocyte subpopulations and functions were examined in the salivary (parotid) gland lymphocytes (SGL) obtained as a cell suspension from a patient with Sjögren's syndrome associated with rheumatoid arthritis, in comparison with peripheral blood lymphocytes (PBL). Serial studies on the lymphocyte subsets in PBL using monoclonal antibodies to helper or suppressor T cell subsets (OKT4 or OKT8) demonstrated a decreased proportion of the OKT8 subset (OKT4/OKT8 ratio: 7.1-34.0). Major infiltrating cells in the gland were surface immunoglobulin-bearing B cells, and 23-35% of the SGL were T cells by both the E-rosetting method and OKT3-monoclonal antibody reactivity. Moreover, OKT4/OKT8 ratios were definitely lower in the SGL (1.0 and 1.7) than those in the PBL of the patient. Mitogen-induced lymphocyte proliferative responses of the SGL were markedly diminished, although the possible participation of defective macrophages was considered. The autologous mixed lymphocyte reaction was low in both PBL and SGL. PBL of the patient showed normal proliferative responses to mitogens except for PWM stimulation. Suppressor effects of the SGL for the proliferative responses of autologous and allogeneic PBL were demonstrated. Con A-induced suppressor function was inducible in the SGL, whereas that function could not be demonstrated in the patient's PBL.

Histamine-triggered localized vasculitis in patients with seropositive rheumatoid arthritis

To gain some insight into the pathogenesis of vasculitis in rheumatoid arthritis, and to investigate its relation to circulating immunoreactants, we injected 50 microliters of histamine intradermally in four seropositive and four seronegative patients with rheumatoid arthritis. Skin biopsies obtained before histamine and at 4 hours after histamine were studied by immunofluorescence microscopy, and skin biopsies 24 hours after histamine were studied by light microscopy. At 4 hours after histamine, all seropositive patients demonstrated deposits of IgM and complement components in dermal vessels; by 24 hours, various degrees of leukocytoclastic vasculitis were noted. Circulating material reactive with Raji cells, C1q, or both, was present in 3/3 seropositive patients. In contrast, none of the seronegative patients exhibited vascular deposits of immunoreactants or vasculitis. The results indicate that patients with rheumatoid arthritis who are seropositive may have circulating complexes with appropriate characteristics to induce vasculitis and that vasoactive substances may be used to trigger their local deposition in vessels.

Defective expression of OKT4 antigen on the cell surface of helper T lymphocytes in a patient with systemic lupus erythematosus

OKT-monoclonal antibodies directed to total T-cells (OKT3), inducer/helper (OKT4) or suppressor/cytotoxic (OKT8) T-cells recognize developmental antigens on human T-cells. We report here an 18 year old male patient with systemic lupus erythematosus who had a prominent decrease in the proportion of OKT4-reactive T-cells in his peripheral blood, although the proportion of OKT3- and OKT8-reactive T-cells were essentially normal. His peripheral blood lymphocytes (PBL) responded well to stimulation by phytohemagglutinin-P (PHA) or concanavalin-A (Con A), which are stimulators for OKT4-reactive T-cells or for both subsets. Furthermore, helper T-cell function for B-cell proliferation was demonstrable in the patient's T-cells which lacked both OKT4 and OKT8 antigens. Trypsinization of PBL from healthy individuals abrogated detection of the OKT4 antigen, and a complete recovery of the antigen was observed after 6 days of culture of the treated PBL. The OKT4 antigen, however, could not be expressed on the patient's PBL after this treatment and incubation. In addition, the patient's serum could not block the recovery of OKT4 antigen on trypsinized T-cells from healthy individuals. The decrease in the percentage of OKT4-reactive T-cells was relatively stable in the patient, while his clinical disease activity and medications were variable. Taken together, these results suggest a defective expression of OKT4 antigen on the helper T-cell subset in this patient.

Red lunulae in a patient with rheumatoid arthritis

Red nails, a distinctive, dusky red, blanchable erythema of the lunula area of the nail bed, has been previously reported three times in the English language literature, in each instance in association with alopecia areata. An identical case of red nails here in association with "classical" rheumatoid arthritis is reported.

Dermatologic conditions reported in patients with rheumatoid arthritis

Dermatologists, while becoming increasingly involved in the diagnosis and management of patients with connective tissue diseases, have left rheumatoid arthritis relatively unexplored. An increased awareness of possible pathomechanisms of rheumatoid arthritis may allow for generalizations that lead to increased understanding of other connective tissue disorders. The types of cutaneous disorders that occur in association with rheumatoid arthritis include: vasoreactive dermatoses (e.g., various forms of vasculitis), which may occur secondary to the circulating immune complexes present in rheumatoid arthritis; autoimmune bullous disorders, which may occur in the setting of a suppressor T cell defect in rheumatoid arthritis; and various miscellaneous cutaneous associations. Hopefully, this review will lead to an increased understanding of both rheumatoid arthritis and the wide array of cutaneous associations of rheumatoid arthritis.

Further characterization of mitogen-induced autorosette-forming cells: correlation with T-cell subsets and with lymphocyte proliferative responses to mitogens

Spontaneous autologous rosette-forming cells (ARFC), which form rosettes with autologous erythrocytes, have been of interest as a subset of thymus-derived lymphocytes (T cells). An association of these cells with concanavalin A (Con A)-induced ARFC has been suggested. Furthermore, the Con A-induced ARFC have been shown to be a suppressor T-cell subset in the Con A-generated suppressor system. We have previously reported the induction of ARFC from T cells by several T-cell mitogens such as phytohemagglutinin-P (PHA) and allogeneic non-T cells other than Con A. In the present report, we further characterized the mitogen-induced ARFC and have extended the study to patients with systemic lupus erythematosus (SLE). We have found that ARFC are also inducible from peripheral blood T cells by pokeweed mitogen (PWM). Studies of T-cell surface markers on the ARFC using OKT monoclonal antibodies confirmed the induction of ARFC from both OKT4- and OKT8-reactive T cells by either Con A, PHA, or PWM stimulation. However, OKT4-reactive T cells were the major cellular source of the ARFC induced by all of the mitogens. In studies of SLE patients, proportions of both Con A- and PWM-induced ARFC were found to be significantly low in PBL of SLE patients treated with moderate or large doses of prednisone, with or without concomitant immunosuppressants, but not in SLE patients without such treatment. Proportional analysis of the T cells and their subsets suggested association of these alterations in the mitogen-induced ARFC with the OKT4-reactive T cells, since a significant decrease in the OKT4-reactive T-cell subset was demonstrated in the PBL of these patients. Proportions of PHA-induced ARFC, however, were not significantly different between SLE patients and healthy adults. Moreover, positive correlations of the mitogen-induced ARFC with lymphocyte proliferative responses to each mitogen were established in both SLE patients and healthy adults. These results further support our previous observation that suggest the receptors for autologous erythrocytes are enhanced or reexpressed on those T cells which are highly activated by mitogens.

Reactivity of mitogen-induced autorosette-forming cells to interleukin 2 (T-cell growth factor)

The reactivity of mitogen-induced autologous rosette-forming cells (ARFC) to interleukin 2 (IL-2; T-cell growth factor) was studied in the present report. Both ARFC-enriched T cells and ARFC-depleted T cells, which were separated from concanavalin A (Con A)-activated T cells, were reactive to this factor. The IL-2 activity was absorbed by both ARFC-enriched and ARFC-depleted T cells, although ARFC-enriched T cells could absorb more IL-2 activity. Furthermore, ARFC were further inducible by IL-2 from non-ARFC. These results suggest the expression of the receptors for IL-2 on both ARFC and non-ARFC following mitogen stimulation. They further support the possibility that mitogen-induced ARFC, rather than being recruited only from such a minor T-cell subset as the spontaneous ARFC, are more likely the result of most T cells being responsive to mitogenic stimulation and expressing the receptors for autologous erythrocytes by the effects of IL-2 and mitogen.