Epistasis and the sensitivity of phenotypic screens for beta thalassaemia

Genetic disorders of haemoglobin, particularly the sickle cell diseases and the alpha and beta thalassaemias, are the commonest inherited disorders worldwide. The majority of affected births occur in low-income and lower-middle income countries. Screening programmes are a vital tool to counter these haemoglobinopathies by: (i) identifying individual carriers and allowing them to make informed reproductive choices, and (ii) generating population level gene-frequency estimates, to help ensure the optimal allocation of public health resources. For both of these functions it is vital that the screen performed is suitably sensitive. One popular first-stage screening option to detect carriers of beta thalassaemia in low-income countries is the One Tube Osmotic Fragility Test (OTOFT). Here we introduce a population genetic framework within which to quantify the likely sensitivity and specificity of the OTOFT in different epidemiological contexts. We demonstrate that interactions between the carrier states for beta thalassaemia and alpha thalassaemia, glucose-6-phosphate dehydrogenase deficiency and Southeast Asian Ovalocytosis have the potential to reduce the sensitivity of OTOFTs for beta thalassaemia heterozygosity to below 70%. Our results therefore caution against the widespread application of OTOFTs in regions where these erythrocyte variants co-occur

Timing and severity of inhibitor development in recombinant versus plasma-derived factor VIII concentrates: a SIPPET analysis

Essentials Recombinant factor VIII (rFVIII) was contrasted with plasma-derived FVIII (pdFVIII). In previously untreated patients with hemophilia A, rFVIII led to more inhibitors than pdFVIII. Inhibitors with rFVIII developed earlier, and the peak rate was higher than with pdFVIII. Inhibitors with rFVIII were more severe (higher titre) than with pdFVIII. Summary: Background The development of neutralizing antibodies (inhibitors) against factor VIII (FVIII) is the most severe complication in the early phases of treatment of severe hemophilia A. Recently, a randomized trial, the Survey of Inhibitors in Plasma-Product Exposed Toddlers (SIPPET) demonstrated a 2-fold higher risk of inhibitor development in children treated with recombinant FVIII (rFVIII) products than with plasma-derived FVIII (pdFVIII) during the first 50 exposure days (EDs). Objective/Methods In this post-hoc SIPPET analysis we evaluated the rate of inhibitor incidence over time by every 5 EDs (from 0 to 50 EDs) in patients treated with different classes of FVIII product, made possible by a frequent testing regime. Results The highest rate of inhibitor development occurred in the first 10 EDs, with a large contrast between rFVIII and pdFVIII during the first 5 EDs: hazard ratio 3.14 (95% confidence interval [CI], 1.01\ue2\u80\u939.74) for all inhibitors and 4.19 (95% CI, 1.18\ue2\u80\u9314.8) for high-titer inhibitors. For patients treated with pdFVIII, the peak of inhibitor development occurred later (6\ue2\u80\u9310 EDs) and lasted for a shorter time. Conclusion These results emphasize the high immunologic vulnerability of patients during the earliest exposure to FVIII concentrates, with the strongest response to recombinant FVIII products

Leprosy post-exposure prophylaxis with single-dose rifampicin (LPEP): an international feasibility programme

Background Innovative approaches are required for leprosy control to reduce cases and curb transmission of Mycobacterium leprae. Early case detection, contact screening, and chemoprophylaxis are the most promising tools. We aimed to generate evidence on the feasibility of integrating contact tracing and administration of single-dose rifampicin (SDR) into routine leprosy control activities. Methods The leprosy post-exposure prophylaxis (LPEP) programme was an international, multicentre feasibility study implemented within the leprosy control programmes of Brazil, India, Indonesia, Myanmar, Nepal, Sri Lanka, and Tanzania. LPEP explored the feasibility of combining three key interventions: systematically tracing contacts of individuals newly diagnosed with leprosy; screening the traced contacts for leprosy; and administering SDR to eligible contacts. Outcomes were assessed in terms of number of contacts traced, screened, and SDR administration rates. Findings Between Jan 1, 2015, and Aug 1, 2019, LPEP enrolled 9170 index patients and listed 179 769 contacts, of whom 174782 (97·2%) were successfully traced and screened. Of those screened, 22 854 (13·1%) were excluded from SDR mainly because of health reasons and age. Among those excluded, 810 were confirmed as new patients (46 per 10 000 contacts screened). Among the eligible screened contacts, 1182 (0·7%) refused prophylactic treatment with SDR. Overall, SDR was administered to 151 928 (86·9%) screened contacts. No serious adverse events were reported. Interpretation Post-exposure prophylaxis with SDR is safe; can be integrated into different leprosy control programmes with minimal additional efforts once contact tracing has been established; and is generally well accepted by index patients, their contacts, and health-care workers. The programme has also invigorated local leprosy control through the availability of a prophylactic intervention; therefore,

Acquired pure red cell aplasia in a child.

Primary acquired pure red cell aplasia is a rare occurrence in childhood. An eleven-year old boy presented to us with pallor, which required multiple packed red cell transfusions. He did not have hepatosplenomegaly, jaundice or lymphadenopathy. Bone marrow examination revealed the diagnosis of pure red cell aplasia. All possible investigations were done to exclude secondary causes of pure red cell aplasia. No secondary cause was found on investigations. Rheumatoid factor and anti-nuclear antibodies were positive. He was started on oral steroids, to which he did not respond. He was then given cyclosporine A. Response to cyclosporine was dramatic and the child now does not require any transfusions

Hidradenitis suppurativa in a HIV-infected child

Hidradenitis suppurativa (HS), a painful and chronic condition, commonly occurs in women and coincides with post-pubertal increase in sex hormones. A 13-year-old pre-pubertal HIV-infected male child presented to our clinic with a discharging right axillary lymph node swelling. The biopsy of the lesion showed features of HS. The patient was treated with oral antibiotics, oral steroids, and local antibiotic wash. Though the patient responded to this treatment, the clinical response was not adequate and the lesion recurred. Subsequently, the child was started on antiretroviral therapy (zidovudine, lamivudine, and nevirapine). Following these medications, the lesions healed and had not recurred till we last examined the child. Thus, this is a rare presentation of a known condition in an HIV-infected pre-pubertal male child, which did not respond to usual modalities of treatment and had to be treated with antiretroviral therapy

Isolation of Streptobacillus moniliformis from the blood of a child with acute lymphoblastic leukaemia

This is an unusual report of isolation of Streptobacillus moniliformis from the blood of a male child with acute lymphoblastic leukaemia. No history of rat bite was there, but rats were present in the house. The possible source of infection may be food or water contaminated with rat excreta. Whether this bacteria can cause opportunistic infection in leukaemic patients, need to be evaluated further

Methionine down-regulates TLR4/MyD88/NF-kappa B signalling in osteoclast precursors to reduce bone loss during osteoporosis

Background and PurposeStudies have demonstrated that a moderate intake of amino acids is associated with development of bone health. Methionine, a sulphur-containing essential amino acid, has been largely implicated for improving cartilage formation, however its physiological significance on bone integrity and functionality have not been elucidated. We investigated whether methionine can prevent osteoporotic bone loss. Experimental ApproachThe anti-resorptive effect of methionine, (250mgkg(-1) body wt administered in drinking water for 10 weeks), was evaluated in ovariectomized (OVX) rats by monitoring changes in bone turnover, formation of osteoclasts from blood-derived mononuclear cells and changes in the synthesis of pro-osteoclastogenic cytokines. Key resultsMethionine improved bone density and significantly decreased the degree of osteoclast development from blood mononuclear cells in OVX rats, as indicated by decreased production of osteoclast markers tartarate resistant acid phosphatase b (TRAP5b) and MIP-1. siRNA-mediated knockdown of myeloid differentiation primary response 88 MyD88], a signalling molecule in the toll-like receptor (TLR) signalling cascade, abolished the synthesis of both TRAP5b and MIP-1 in developing osteoclasts. Methionine supplementation disrupted osteoclast development by inhibiting TLR-4/MyD88/NF-B pathway. Conclusions and ImplicationsTLR-4/MyD88/NF-B signalling pathway is integral for osteoclast development and this is down-regulated in osteoporotic system on methionine treatment. Methionine treatment could be beneficial for the treatment of postmenopausal osteoporosis