Electrostatically Mediated Attractive Self-Interactions and Reversible Self-Association of Fc-Fusion Proteins.

Attractive self-interactions and reversible self-association are implicated in many problematic solution behaviors for therapeutic proteins, such as irreversible aggregation, elevated viscosity, phase separation, and opalescence. Protein self-interactions and reversible oligomerization of two Fc-fusion proteins (monovalent and bivalent) and the corresponding fusion partner protein were characterized experimentally with static and dynamic light scattering as a function of pH (5 and 6.5) and ionic strength (10 mM to at least 300 mM). The fusion partner protein and monovalent Fc-fusion each displayed net attractive electrostatic self-interactions at pH 6.5 and net repulsive electrostatic self-interactions at pH 5. Solutions of the bivalent Fc-fusion contained higher molecular weight species that prevented quantification of typical interaction parameters (B22 and kD). All three of the proteins displayed reversible self-association at pH 6.5, where oligomers dissociated with increased ionic strength. Coarse-grained molecular simulations were used to model the self-interactions measured experimentally, assess net self-interactions for the bivalent Fc-fusion, and probe the specific electrostatic interactions between charged amino acids that were involved in attractive electrostatic self-interactions. Mayer-weighted pairwise electrostatic energies from the simulations suggested that attractive electrostatic self-interactions at pH 6.5 for the two Fc-fusion proteins were due to cross-domain interactions between the fusion partner domain(s) and the Fc domain.

Case Report: Anti-MDA-5 dermatomyositis in a resource-limited setting.

Anti-Melanoma Differentiation-Associated gene 5 (Anti-MDA-5) dermatomyositis is a rare subtype of inflammatory myopathy characterized by unique skin lesions, rapidly progressive interstitial lung disease, and skeletal muscle inflammation. It has a high mortality rate in the absence of early treatment. However, diagnosis of this entity is challenging in a country like Nepal because of various constraints such as lack of expert rheumatologists and resource limitations. Here we describe a case of one patient who had presented to us with generalized weakness, cough and shortness of breath who was finally diagnosed as anti-MDA-5 dermatomyositis. He responded to combination of immunosuppressives and is currently doing well. This case highlights the diagnostic and therapeutic challenges in managing such cases in a resource-limited setting.

Th1, Th2 and Th17 inflammatory pathways synergistically predict cardiometabolic protein expression in serum of COVID-19 patients.

A predominant source of complication in SARS-CoV-2 patients arises from a severe systemic inflammation that can lead to tissue damage and organ failure. The high inflammatory burden of this viral infection often results in cardiovascular comorbidities. A better understanding of the interaction between immune pathways and cardiovascular proteins might inform medical decisions and therapeutic approaches. In this study we hypothesized that helper T-cell inflammatory pathways (Th1, Th2 and Th17) synergistically correlate with cardiometabolic proteins in serum of COVID-19 patients. We found that Th1, Th2 and Th17 cytokines and chemokines are able to predict expression of 186 cardiometabolic proteins profiled by Olink proteomics.

Dengue and scrub typhus co-infection causing septic shock.

A 33-year-old female presented with a history of high-grade fever, cough, dyspnea, joint pain and myalgia. On examination, the patient was febrile with tachycardia, hypotension and decreased oxygen saturation. Chest auscultation revealed bilateral decreased air entry with crepitation supported by bilateral pulmonary infiltrates on chest X-ray. The laboratory investigations showed leukocytosis, thrombocytopenia, transaminitis and renal impairment. The patient was treated with intravenous fluids, ceftriaxone and levofloxacin; however, there was no clinical improvement till 48 h. She was then diagnosed with scrub typhus and dengue co-infection via serologies. Doxycycline was started following which the patient improved in 24 h. Scrub typhus can present with septic shock but does not respond to the usual antibiotics and the addition of doxycycline will result in rapid clinical improvement. Co-infection with other tropical diseases such as dengue is also common, hence it is important to test based on local endemicity.

Case Report: Adult Onset Still's Disease after vaccination against Covid-19.

Vaccination against the virus responsible for COVID-19 has become key in preventing mortality and morbidity related to the infection. Studies have shown that the benefits of vaccination outweigh the risks. However, there are concerns regarding serious adverse events of some vaccines, although they are fortunately rare. Here, we report a case of a 47-year-old female from Kathmandu who presented with high grade fever, dry cough and erythematous rash a week after exposure to the Oxford-AstraZeneca vaccine. She had hepatosplenomegaly, persistent leucocytosis, anaemia and thrombocytosis along with markedly raised inflammatory markers. Her tests for infectious causes and haematological malignancies were negative and she showed no response to multiple antibiotics. Finally, she had a dramatic response to steroids with disappearance of fever and normalization of other laboratory parameters. Hence, she was diagnosed with Adult-onset Still's Disease (AOSD). She was under methotrexate and prednisolone tapering dose and doing well as of the time of writing. The trigger for the disease was hypothesized to be the vaccine because of the strong temporal association.

Case Report: Using basic liver function tests as a guide to suspected Wilson's disease.

We present a case of a 36-year-old female patient who presented with subacute liver disease with a history of alcohol abuse. On basic liver function tests (LFT), she had aspartate transaminase / alanine transaminase > 2.2 and alkaline phosphatase / total bilirubin < 4. This pattern in acute liver failure patients signifies Wilson's disease. Its presence in our patient with subacute liver disease also prompted us to suspect Wilson's disease and we extended the liver disease screen to include slit lamp eye examination for Kayser-Fleischer rings, serum ceruloplasmin and 24-hour urinary copper level, which led to the diagnosis. She improved clinically and biochemically with zinc acetate therapy.  As screening for rare diseases is not always possible in low-income countries, this case demonstrates the usefulness of the basic LFT as a guide for suspecting Wilson's disease in patients with liver disease.

Case Report: Pulmonary tuberculosis and raised transaminases without pre-existing liver disease- Do we need to modify the antitubercular therapy?

We report a case of pulmonary tuberculosis with transaminitis during the presentation but without any pre-existing liver disease or hepatotoxic drug use. This is a fairly common scenario seen in tuberculosis endemic areas; however, this is an under reported condition in the literature and guidelines for its management has not been established. Many clinicians including the authors have treated such cases with modified liver friendly regimens in fear of increasing the hepatotoxicity with standard drugs. However, the modified regimens may not be optimal in treating the underlying tuberculosis. In this report, we gave full dose standard antitubercular drugs, and the liver injury resolved evidenced by normalization of transaminases.

Case Report: Co-existence of sarcoidosis and Takayasu arteritis.

Takayasu arteritis is a rare systemic large vessel vasculitis affecting the aorta and its branches. Sarcoidosis, too, is an inflammatory disease. Both entities are granulomatous conditions with a questionable association in their etiopathogenesis. Only a few cases of their coexistence have been reported in the literature. To our knowledge, no such cases have been reported from Nepal. We report a Nepalese woman who presented with non-productive cough, progressive shortness of breath and chest tightness of 3 years duration. She had a history of recurrent bilateral granulomatous uveitis over the previous 3 years. Examination revealed clubbing of digits, absent pulses over the left radial, ulnar and brachial arteries, and a weak pulse over the right arm including the bilateral carotid arteries. Pulmonary function test showed restrictive pattern, a high-resolution computed tomography (HRCT) scan of the chest revealed findings suggestive of pulmonary sarcoidosis. A CT angiogram suggested large vessel vasculitis. Bronchoscopy with biopsy revealed granulomatous inflammation, negative for malignancy and tuberculosis. She was hence, diagnosed with co-existing Takayasu arteritis and sarcoidosis, and treated with Prednisolone 60 mg once daily with dramatic improvement over 4 days and was discharged stable on domiciliary oxygen. She is currently on azathioprine 50 mg, prednisolone 10 mg without the need for supplemental oxygen. This case report highlights the importance of a proper physical examination as a guide to the use of modern technology in making a correct diagnosis. Furthermore, in countries where tuberculosis is endemic, it should always come as the most important differential diagnosis of granulomatous inflammation.

Adverse events with ayurvedic medicines- possible adulteration and some inherent toxicities.

Ayurvedic medicine, a traditional system of medicine practiced in the Indian subcontinent is considered to be devoid of adverse events. We report three cases which highlight the possibility of adverse events related with the use of ayurvedic products. A 35 year old woman with hepatitis took ayurvedic powder medicine and swarnabhasma (gold salt) and had her liver injury worsened, possibly due to alkaloids, and developed nephrotic syndrome, possibly due to gold salt. A 57 year old hypertensive man was taking ayurvedic medicine containing reserpine which had long been withdrawn from the allopathic system of medicine due to wide range of side effects. A 47 year old woman with rheumatoid arthritis was taking an unknown tablet containing steroid as an adulterant for 2 years and developed side effects typical of steroid excess. We would like to highlight the fact that ayurvedic medicines do have propensity to cause adverse events due to adulteration or inherent constituents like alkaloids, and hence may not always be completely safe.

Case Report: Cryptococcal meningitis in an apparently immunocompetent patient in Nepal - challenges in diagnosis and treatment.

A 50 year old woman from Nepal had clinical features suggestive of meningitis. Cerebrospinal fluid (CSF) analysis was normal except for the presence of cryptococcal antigen. The inclusion of test for Cryptococcus in the CSF helped in making the diagnosis of cryptococcal meningitis in our patient who was apparently immunocompetent. Treatment with liposomal amphotericin B could not be started on time due financial constraints. The patient had a stroke and further deteriorated. Liposomal amphotericin B is stocked by the government of Nepal for free supply to patients with visceral leishmaniasis, but the policy does not allow the drug to be dispensed for other infections. The family members of our patient acquired the drug within a few days from a government center using their political connections and following administering the treatment the patient improved. This case demonstrates the utility of considering cryptococcal meningitis as a differential diagnosis, and including tests for Cryptococcus when dealing with immunocompetent patients presenting with meningitis. It also demonstrates the effects of the sociopolitical situation on health care delivery in low- and middle-income countries (LMICs) such as Nepal.

Case Report: Gastric Mucormycosis- a rare but important differential diagnosis of upper gastrointestinal bleeding in an area of Helicobacter pylori endemicity.

A 57 years female from the hills of Nepal presented with upper gastrointestinal bleeding with gastric ulcer evident on endoscopy. Though initially treated with Helicobacter pylori ( H. pylori) eradication therapy alone, biopsy later on revealed both mucormycosis and H. pylori infection. She was then treated with antifungals liposomal amphotericin B followed by posaconazole which led to complete recovery. Mucormycosis is a rare but life-threatening fungal disease of immunocompromised host though our patient was immunocompetent. If recognized and treated at early stage, as in our patient, prognosis is good. A high index of suspicion is required for considering this disease in H. pylori endemic regions such as Nepal, and is crucial for early recognition and treatment.

Extrapulmonary tuberculosis: a debilitating and often neglected public health problem.

We report a case of a 33-year-old woman from Nepal who presented to a hospital with paraplegia. She was found to have pulmonary tuberculosis (TB) with lumbar spine involvement, and bilateral psoas abscesses. She had no initial symptoms attributable to pulmonary involvement. Her delayed presentation to the hospital led to complication of TB spine, which compromised the life of this woman working as a labourer. Early diagnosis and treatment of extrapulmonary TB is essential. Awareness regarding symptoms of different forms of extrapulmonary TB and making diagnostic modalities such as CT scan, MRI or biopsy readily available through insurance schemes are some important measures to minimise the problem so that complications like paraplegia as in our patient with spinal TB can potentially be avoided.

Meningitis due to scrub typhus: the importance of a differential diagnosis in an endemic area.

A patient with fever and neck stiffness was treated as partially treated bacterial meningitis based on history, examination and cerebrospinal fluid analysis. After initial improvement with ceftriaxone, vancomycin and dexamethasone, symptoms recurred. Fever resolved promptly after treatment was started with doxycycline, when scrub typhus immunoglobulin M test came positive. Meningitis is a well-known complication of scrub typhus. However, scrub typhus is seldom considered in the differential diagnosis of meningitis in the Indian subcontinent. Early diagnosis and prompt institution of doxycycline therapy may lead to early cure of scrub typhus even when features of meningitis supervene. However, ceftriaxone which is commonly used to treat bacterial meningitis is suboptimal in the treatmenwgt36t of scrub typhus.