The simultaneous occurrence of livedoid vasculopathy and lymphocytic thrombophilic arteritis in six cases

Lymphocytic thrombophilic arteritis and livedoid vasculopathy may both present with livedo racemosa and ulceration. We present 6 cases with features of both conditions, raising the possibility that they are either closely linked or are part of a spectrum of the same condition.

Epitope length variants balance protective immune responses and viral escape in HIV-1 infection

Cytotoxic T lymphocyte (CTL) and natural killer (NK) cell responses to a single optimal 10-mer epitope (KK10) in the human immunodeficiency virus type-1 (HIV-1) protein p24Gag are associated with enhanced immune control in patients expressing human leukocyte antigen (HLA)-B∗27:05. We find that proteasomal activity generates multiple length variants of KK10 (4-14 amino acids), which bind TAP and HLA-B∗27:05. However, only epitope forms ≥8 amino acids evoke peptide length-specific and cross-reactive CTL responses. Structural analyses reveal that all epitope forms bind HLA-B∗27:05 via a conserved N-terminal motif, and competition experiments show that the truncated epitope forms outcompete immunogenic epitope forms for binding to HLA-B∗27:05. Common viral escape mutations abolish (L136M) or impair (R132K) production of KK10 and longer epitope forms. Peptide length influences how well the inhibitory NK cell receptor KIR3DL1 binds HLA-B∗27:05 peptide complexes and how intraepitope mutations affect this interaction. These results identify a viral escape mechanism from CTL and NK responses based on differential antigen processing and peptide competition.

Impact of place of residence, frailty and other factors on rehabilitation outcomes post hip fracture

BACKGROUND

Following hip fracture surgery, patients from residential care are frequently excluded from inpatient rehabilitation. We aimed to assess the impact of place of residence and other factors such as frailty on rehabilitation outcomes after hip fracture surgery.

METHODS

Retrospective cohort study. Outcome measures included Functional Independence Measure efficiency, discharge destination and recovery of pre-fracture mobility. Univariable and multivariable linear or logistic regression analyses were performed.

SETTING

One general rehabilitation and two geriatric evaluation and management wards in a large public tertiary teaching hospital.

PARTICIPANTS

A total of 844 patients who underwent inpatient rehabilitation after hip fracture surgery from 2010 to 2018.

RESULTS

There were 139 (16%) patients from residential care. Being from residential care was not an independent predictor of poor outcomes. Premorbid frailty (Clinical Frailty Scale) was the strongest independent predictor of poorer Functional Independence Measure efficiency, inability to recover pre-fracture mobility and return to community dwelling. Dementia and delirium were also independently predictive of poor outcomes across all measures. Age > 90 years was independently predictive of inability to recover pre-fracture mobility and return to community dwelling.

CONCLUSION

Being from residential care is not independently associated with poor outcomes following inpatient rehabilitation after hip fracture surgery and should not be the basis for excluding these patients from rehabilitation. Major predictors of poorer outcomes include premorbid frailty, dementia, delirium and age > 90 years. If able and motivated, those with potentially reversible functional limitations should be given the opportunity to participate in inpatient rehabilitation as even small gains can have a significant impact on quality of life.

Acral lentiginous melanoma: Clinicopathologic and survival differences according to tumour location

BACKGROUND/OBJECTIVES

Acral lentiginous melanoma (ALM) is a melanoma subtype associated with atypical locations on the hands and feet and advanced disease at diagnosis. There is a limited understanding of whether the survival is similar for nail, non-nail, lower limb and upper limb ALM patients. We therefore explored clinicopathologic characteristics and melanoma-specific survival of ALM patients according to tumour location.

METHODS

A prospectively collected cohort study was performed of all primary invasive cutaneous acral lentiginous melanomas with known thickness and tumour location reviewed at a tertiary referral centre over 21 years.

RESULTS

A total of 101 ALM patients were reviewed from 1994 until 2016. The majority of cases (82/101) occurred on the feet. Hand ALMs were thicker and more likely to be ulcerated than feet ALMs (P = 0.05 and 0.02, respectively); however, survival was not statistically different between these two groups (univariate HR 0.48 P = 0.11, 95% CI, 0.20-1.17; multivariate HR 0.67 P = 0.40, 95% CI, 0.27-1.69, respectively). Non-nail ALM patients had longer survival when compared to nail ALM on univariate analysis (HR 0.40, 95% CI, 0.17 to 0.90) which was accounted for by Breslow thickness and ulceration (multivariate HR 0.56, 95% CI, 0.24 to 1.34).

CONCLUSIONS

The reduced melanoma-specific survival in nail ALM patients was likely due to their greater thickness and ulceration. Although hand ALMs are thicker and more frequently ulcerated, this is likely due to the higher proportion of nail ALMs present in this location.

The anatomic distribution of cutaneous melanoma: A detailed study of 5141 lesions

BACKGROUND/OBJECTIVES

There is evidence that cutaneous melanomas at different anatomic sites present with distinctive clinicopathologic features. We examined the anatomic distribution of cutaneous melanoma and its variation by patient characteristics, subtype and Breslow thickness, using high-resolution anatomic site data.

METHODS

A cross-sectional study was performed of all primary cutaneous melanoma cases managed at a tertiary referral centre, analysing prospectively collected clinical data across 50 anatomic subsites.

RESULTS

The study included 5141 in situ or invasive melanomas; most were invasive (76.2%), and the median Breslow thickness of invasive lesions was 1.0 mm. Superficial spreading (57.2%), lentigo maligna (20.8%) and nodular (12.2%) were the most common histopathological subtypes. Sun-exposed sites such as the female nose and cheek, the male ear, as well as the upper back in both sexes had the highest incidence of melanoma per unit area. When compared to the posterior forearm, the scalp, ear, preauricular, perioral, subungual and plantar sites had thicker invasive melanomas (each P < 0.05). The peri-auricular, ear and cheek had the highest incidence of nodular melanoma per unit area. There were subtype-, age- and sex-specific differences in melanoma anatomic distribution.

CONCLUSION

Melanoma most commonly arises in sun-exposed facial areas, as well as the upper back. Increased thickness is found for melanoma in acral and many head and neck sites. Nodular melanoma is more likely to occur in head and neck sites including the peri-auricular area, ear and cheek. Clinicians should carefully assess these sites during skin examinations.

Lymphocytic thrombophilic arteritis and cutaneous polyarteritis nodosa: Clinicopathologic comparison with blinded histologic assessment

BACKGROUND

Lymphocytic thrombophilic arteritis (LTA), or macular lymphocytic arteritis, is defined by a primary lymphocytic vasculitis. However, the nosology of LTA has been controversial, with speculation that it may represent an indolent non-nodule-forming variant of cutaneous polyarteritis nodosa (cPAN).

OBJECTIVE

This study compares the clinicopathologic features of patients with LTA or cPAN to assess if these conditions should be considered distinct entities.

METHODS

This is a cross-sectional study of all LTA and cPAN cases at a single tertiary center using prospectively collected clinical data and blinded histologic assessment.

RESULTS

The study included 17 patients with LTA and 13 patients with cPAN. Clinically, cases of LTA were distinguished by a more widespread pattern of livedo racemosa, which was noninfiltrated and asymptomatic. In contrast, cPAN was associated with localized starburst livedo, purpura, and episodic features including nodules, pain, and large inflammatory ulcers. When patients were separated according to the presence (>5%) or paucity (≤5%) of neutrophils on blinded histology review, they had distinct clinical features and differences in disease course.

LIMITATIONS

This was a single-center study.

CONCLUSION

Our data support the classification of LTA and cPAN as separate entities rather than a spectrum of the same disorder and highlight the importance of clinicopathologic correlation in distinguishing these conditions.

Clinically amelanotic or hypomelanotic melanoma: Anatomic distribution, risk factors, and survival

BACKGROUND

The recognition and diagnosis of clinically amelanotic or hypomelanotic melanoma is a challenge.

OBJECTIVE

This study aimed to examine the anatomic distribution and risk factors associated with clinically amelanotic or hypomelanotic melanoma and compare the survival of patients with clinically amelanotic or hypomelanotic melanoma with that of patients with pigmented melanoma.

METHODS

A prospective cohort study of all cases of primary invasive melanoma managed at a tertiary referral center was performed.

RESULTS

There were a total of 3913 invasive melanomas, and 384 (9.8%) were clinically amelanotic or hypomelanotic. Skin phototype I; red as well as blonde hair color; actinic keratoses; nodular, desmoplastic, and lentigo maligna subtype; increased Breslow thickness; and mitoses were independently associated with amelanotic or hypomelanotic melanoma (P < .05). After adjustment for subtype and thickness, the face, ears, lateral aspect of the neck, upper portion of the arm, posterior aspect of the forearm, dorsal aspect of the hand, and anterior aspect of the lower portion of the leg were associated with increased odds of amelanotic or hypomelanotic melanoma when compared with the upper portion of the back (P < .05). Mortality risk from melanoma appeared greater for amelanotic or hypomelanotic melanoma than for pigmented melanoma (hazard ratio, 1.5; 95% confidence interval, 1.1-2.1) but was similar once Breslow thickness was taken into account.

LIMITATIONS

Single tertiary referral center.

CONCLUSION

Although clinically amelanotic or hypomelanotic melanoma can occur on all body sites, it is more common on chronically sun-exposed areas. Clinicians should have an increased index of suspicion in patients with a sun-sensitive skin phenotype, red hair, and associated actinic keratoses.

Postcardiac injury syndrome and stroke following permanent pacemaker insertion

An 80-year-old woman initially presented with an episode of pleuritic chest pain 10 days after implantation of a dual chamber permanent pacemaker. She returned to hospital a day later with vomiting and fever. She was found to have new atrial fibrillation in addition to right-sided weakness and dysarthria. An infarct in the left anterior inferior cerebellar artery territory was later confirmed on CT. She continued to have recurrent febrile episodes associated with vomiting and dyspnoea. Extensive investigations for infection were negative, and her symptoms were initially attributed to aspiration pneumonia. The patient gradually deteriorated despite antibiotics and became progressively short of breath, with development of large pleural and pericardial effusions. A diagnosis of postcardiac injury syndrome was made after exclusion of other differentials. The patient recovered well after pleurocentesis, pericardiocentesis and a pericardial window, with resolution of symptoms without further medical therapy.

Three cases of lymphocytic thrombophilic arteritis presenting with an annular eruption

We describe three patients who presented with a striking erythematous non-blanching annular eruption and features of lymphocytic thrombophilic arteritis (LTA), with a prominent lymphocytic vasculitis involving deep dermal vessels. Lymphocytic inflammation was also evident in the superficial vessels and one patient had small superficial ulcers over the ankle area resembling livedoid vasculopathy (LV). Multiple biopsies demonstrated a persistent absence of neutrophils in the infiltrate consistent with a lymphocytic process. In addition to highlighting the annular morphology as a novel presentation of LTA, these cases suggest a possible relationship between LV and LTA and support the notion that they are distinct from neutrophilic vasculitides such as cutaneous polyarteritis nodosa.

Tuberculous pericarditis leading to cardiac tamponade: importance of screening prior to immunosuppression

Mycobacterium tuberculosis (TB) presenting with pericardial disease complicated by cardiac tamponade is rare in the developed world, although it occurs more frequently in the context of immunosuppression. In this report, a 74‐year‐old man on methotrexate for rheumatoid arthritis presented with fever, productive cough and cough‐induced syncope. During his admission, he developed clinical signs of cardiac tamponade confirmed on an echocardiogram, which showed a massive pericardial effusion. He was treated with an urgent pericardiocentesis and a pericardial window. Subsequently, TB polymerase chain reaction of pericardial fluid unexpectedly returned positive, and he was commenced on standard quadruple therapy for TB, as well as high‐dose prednisolone. Notably, the patient did not have a history suggestive of previous TB exposure, and no screening investigations had been performed prior to initiation of methotrexate. This case highlights the importance of TB screening prior to immunosuppressive therapy, even in populations considered low risk for latent disease.

Pentoxifylline: An effective therapy for necrobiosis lipoidica

Necrobiosis lipoidica (NL) is a rare chronic inflammatory granulomatous skin disorder that remains challenging to treat. Here we report three patients at different stages of disease successfully treated with pentoxifylline, a haemorrheological and anti-inflammatory agent. We demonstrate for the first time that early stage NL may be completely reversible with this treatment. Our findings are also consistent with previous isolated reports showing the effectiveness of pentoxifylline in treating ulcerative NL.

APOBEC3G-induced hypermutation of human immunodeficiency virus type-1 is typically a discrete "all or nothing" phenomenon

The rapid evolution of Human Immunodeficiency Virus (HIV-1) allows studies of ongoing host-pathogen interactions. One key selective host factor is APOBEC3G (hA3G) that can cause extensive and inactivating Guanosine-to-Adenosine (G-to-A) mutation on HIV plus-strand DNA (termed hypermutation). HIV can inhibit this innate anti-viral defense through binding of the viral protein Vif to hA3G, but binding efficiency varies and hypermutation frequencies fluctuate in patients. A pivotal question is whether hA3G-induced G-to-A mutation is always lethal to the virus or if it may occur at sub-lethal frequencies that could increase viral diversification. We show in vitro that limiting-levels of hA3G-activity (i.e. when only a single hA3G-unit is likely to act on HIV) produce hypermutation frequencies similar to those in patients and demonstrate in silico that potentially non-lethal G-to-A mutation rates are ∼10-fold lower than the lowest observed hypermutation levels in vitro and in vivo. Our results suggest that even a single incorporated hA3G-unit is likely to cause extensive and inactivating levels of HIV hypermutation and that hypermutation therefore is typically a discrete "all or nothing" phenomenon. Thus, therapeutic measures that inhibit the interaction between Vif and hA3G will likely not increase virus diversification but expand the fraction of hypermutated proviruses within the infected host.

Management of nonvariceal upper gastrointestinal bleeding

Nonvariceal upper gastrointestinal bleeding is unique from variceal bleeding in terms of patient characteristics, management, rebleeding rates, and prognosis, and should be managed differently. The majority of nonvariceal upper gastrointestinal bleeds will not rebleed once treated successfully. The incidence is 80 to 90% of all upper gastrointestinal bleeds and the mortality is between 5 to 10%. The causes include nonacid-related ulceration from tumors, infections, inflammatory disease, Mallory-Weiss tears, erosions, esophagitis, dieulafoy lesions, angiodysplasias, gastric antral vascular ectasia, and portal hypertensive gastropathy. Rarer causes include hemobilia, hemosuccus pancreaticus, and aortoenteric fistulas. Hematemesis and melena are the key features of bleeding from the upper gastrointestinal tract, but fresh per rectal bleeding may be present in a rapidly bleeding lesion. Resuscitation and stabilization before endoscopy leads to improved outcomes. Fluid resuscitation is essential to avoid hypotension. Though widely practiced, there is currently insufficient evidence to show that routine red cell transfusion is beneficial. Coagulopathy requires correction, but the optimal international normalized ratio has not been determined yet. Risk stratification scores such as the Rockall and Glasgow-Blatchford scores are useful to predict rebleeding, mortality, and to determine the urgency of endoscopy. Evidence suggests that high-dose proton pump inhibitors (PPI) should be given as an infusion before endoscopy. If patients are intolerant of PPIs, histamine-2 receptor antagonists can be given, although their acid suppression is inferior. Endoscopic therapy includes thermal methods such as coaptive coagulation, argon plasma coagulation, and hemostatic clips. Four quadrant epinephrine injections combined with either thermal therapy or clipping reduces mortality. In hypoxic patients, endoscopy masks allow high-flow oxygen during upper gastrointestinal endoscopy. The risk of rebleeding reduces after 72 hours. In rebleeding, repeat endoscopy is useful and persistent failure of endoscopic therapy mandates either embolization or surgery. In this review, we analyze the management of nonvariceal upper gastrointestinal bleeding with evidence from the currently published clinical trials.

Collagen remodelling by airway smooth muscle is resistant to steroids and β₂-agonists

Bi-directional interactions between airway smooth muscle (ASM) and the altered extracellular matrix (ECM) may influence airway wall remodelling and ASM function in asthma. We have investigated the capacity of cultured human ASM to reorganise the structure of three-dimensional collagen gels and the effects of endothelin (ET)-1 and agents used to treat asthma. Human ASM cells were cast in type I collagen gels. Reductions in gel area over 72 h were determined in the absence and presence of ET-1 and potential inhibitors, steroids and β₂-adrenoceptor agonists. Changes in gel wet weights and hydroxyproline content were measured and ASM gel morphology was examined by scanning electron microscopy. Cell density-dependent reductions in gel area were augmented by ET-1, mediated via ET(A) receptors. This process was not associated with ASM contraction or proliferation, but was consistent with ASM tractional remodelling and migration leading to collagen condensation rather than collagen degradation within gels. The collagen remodelling by ASM was unaffected by salbutamol and/or budesonide. This study demonstrates an additional potential role for ASM in ECM regulation and dysregulation in airways disease that is resistant to steroids and β₂-adrenoceptor agonists. Therapy-resistant collagen condensation within ASM bundles may facilitate ECM-ASM interactions and contribute to increased internal airways resistance.

Antigen processing influences HIV-specific cytotoxic T lymphocyte immunodominance

Although cytotoxic T lymphocytes (CTLs) in people infected with human immunodeficiency virus type 1 can potentially target multiple virus epitopes, the same few are recognized repeatedly. We show here that CTL immunodominance in regions of the human immunodeficiency virus type 1 group-associated antigen proteins p17 and p24 correlated with epitope abundance, which was strongly influenced by proteasomal digestion profiles, affinity for the transporter protein TAP, and trimming mediated by the endoplasmatic reticulum aminopeptidase ERAAP, and was moderately influenced by HLA affinity. Structural and functional analyses demonstrated that proteasomal cleavage 'preferences' modulated the number and length of epitope-containing peptides, thereby affecting the response avidity and clonality of T cells. Cleavage patterns were affected by both flanking and intraepitope CTL-escape mutations. Our analyses show that antigen processing shapes CTL response hierarchies and that viral evolution modifies cleavage patterns and suggest strategies for in vitro vaccine optimization.

A Rab-E GTPase mutant acts downstream of the Rab-D subclass in biosynthetic membrane traffic to the plasma membrane in tobacco leaf epidermis

The function of the Rab-E subclass of plant Rab GTPases in membrane traffic was investigated using a dominant-inhibitory mutant (RAB-E1(d)[NI]) of Arabidopsis thaliana RAB-E1(d) and in vivo imaging approaches that have been used to characterize similar mutants in the plant Rab-D2 and Rab-F2 subclasses. RAB-E1(d)[NI] inhibited the transport of a secreted green fluorescent protein marker, secGFP, but in contrast with dominant-inhibitory RAB-D2 or RAB-F2 mutants, it did not affect the transport of Golgi or vacuolar markers. Quantitative imaging revealed that RAB-E1(d)[NI] caused less intracellular secGFP accumulation than RAB-D2(a)[NI], a dominant-inhibitory mutant of a member of the Arabidopsis Rab-D2 subclass. Furthermore, whereas RAB-D2(a)[NI] caused secGFP to accumulate exclusively in the endoplasmic reticulum, RAB-E1(d)[NI] caused secGFP to accumulate additionally in the Golgi apparatus and a prevacuolar compartment that could be labeled by FM4-64 and yellow fluorescent protein (YFP)-tagged Arabidopsis RAB-F2(b). Using the vacuolar protease inhibitor E64-d, it was shown that some secGFP was transported to the vacuole in control cells and in the presence of RAB-E1(d)[NI]. Consistent with the hypothesis that secGFP carries a weak vacuolar-sorting determinant, it was shown that a secreted form of DsRed reaches the apoplast without appearing in the prevacuolar compartment. When fused to RAB-E1(d), YFP was targeted specifically to the Golgi via a saturable nucleotide- and prenylation-dependent mechanism but was never observed on the prevacuolar compartment. We propose that RAB-E1(d)[NI] inhibits the secretory pathway at or after the Golgi, causing an accumulation of secGFP in the upstream compartments and an increase in the quantity of secGFP that enters the vacuolar pathway.

Protein retention and localization in the endoplasmic reticulum and the golgi apparatus

Protein transport along the secretory pathway is supported by a noria of vesicles that bud and fuse, load and unload their cargo from one compartment into the other. However, despite this constant flow-through of proteins and lipids the various compartments of the secretory pathway are able to maintain their own specific composition. Here, we discuss recent insights into mechanisms of protein retention and localization that are necessary for the maintenance of endoplasmic reticulum (ER)- and Golgi-associated typical functions such as protein folding and glycosylation in plant cells.