Characterisation of rare spontaneous HIV viral controllers attending a national UK clinical service using a combination of serology and molecular diagnostic assays

We report outcomes and novel characterisation of a unique cohort of 42 individuals with persistently indeterminate HIV status, the majority of whom are HIV viral controllers.

Eligible individuals had indeterminate or positive HIV serology, but persistently undetectable HIV RNA by commercial assays and were not taking ART. Routine investigations included: HIV Western blot; HIV viral load; qualitative HIV-1 DNA; co-infection screen and T-cell quantification. Research assays included T-cell activation; ART measurement; single copy assays detecting HIV-1 RNA and DNA and plasma cytokine quantification. HIV seropositivity was defined as ≥3 bands on Western blot; molecular positivity as detection of HIV RNA or DNA.

HIV infection was excluded in 10/42 referrals, remains unconfirmed in 2/42 and was confirmed in 30/42, who were identified as HIV elite controllers (EC), normal CD4 T-cell counts (median 820/ml, range 805-1336) and normal CD4:CD8 ratio (median 1.8, range 1.2-1.9). ECs had a median duration of elite control of 6 years (IQR=4-14). ART was undetected in all 23 tested. Two distinct categories of EC were identified: molecular-positive (n=20) and molecular-negative (n=10).

HIV status was resolved for 95% of referrals with the majority diagnosed as EC. The clinical significance of the two molecular categories amongst EC requires further investigation.

Detection of HTLV-1 proviral DNA in cell-free DNA: Potential for non-invasive monitoring of Adult T cell leukaemia/lymphoma using liquid biopsy?

Introduction

Fragmented genomic DNA is constitutively released from dying cells into interstitial fluid in healthy tissue. In cancer, this so-called 'cell-free' DNA (cfDNA) released from dying malignant cells encodes cancer-associated mutations. Thus, minimally invasive sampling of cfDNA in blood plasma can be used to diagnose, characterise and longitudinally monitor solid tumours at remote sites in the body. ~5% of carriers of Human T cell leukaemia virus type 1 (HTLV-1) develop Adult T cell leukaemia/lymphoma (ATL), and a similar percentage develop an inflammatory CNS disease, HTLV-1 associated myelopathy (HAM). In both ATL and HAM, high frequencies of HTLV-1 infected cells are present in the affected tissue: each carrying an integrated DNA copy of the provirus. We hypothesised that turnover of infected cells results in the release of HTLV-1 proviruses in cfDNA, and that analysis of cfDNA from infected cells in HTLV-1 carriers might contain clinically useful information pertaining to inaccessible sites in the body- e.g. for early detection of primary or relapsing localised lymphoma type ATL. To evaluate the feasibility of this approach, we tested for HTLV-1 proviruses in blood plasma cfDNA.

Methods

CfDNA (from blood plasma) and genomic DNA (gDNA, from peripheral blood mononuclear cells, PBMC) was isolated from blood from 6 uninfected controls, 24 asymptomatic carriers (AC), 21 patients with HAM and 25 patients with ATL. Proviral (HTLV-1 Tax) and human genomic DNA (the beta globin gene, HBB) targets were quantified by qPCR using primer pairs optimised for fragmented DNA.

Results

Pure, high quality cfDNA was successfully extracted from blood plasma of all study participants. When compared with uninfected controls, HTLV-1 carriers had higher concentrations of cfDNA circulating in their blood plasma. Patients with ATL who were not in remission had the highest levels of blood plasma cfDNA in any group studied. HTLV-1 proviral DNA was detected in 60/70 samples obtained from HTLV-1 carriers. The proviral load (percentage of cells carrying proviruses) was approximately tenfold lower in plasma cfDNA than in PBMC genomic DNA, and there was a strong correlation between the proviral load in cfDNA and PBMC genomic DNA in HTLV-1 carriers that did not have ATL. cfDNA samples in which proviruses were undetectable also had very low proviral load in PBMC genomic DNA. Finally, detection of proviruses in cfDNA of patients with ATL was predictive of clinical status: patients with evolving disease had higher than expected total amount of proviruses detectable in plasma cfDNA.

Discussion

We demonstrated that (1) HTLV-1 infection is associated with increased levels of blood plasma cfDNA, (2) proviral DNA is released into blood plasma cfDNA in HTLV-1 carriers and (3) proviral burden in cfDNA correlates with clinical status, raising the possibility of developing assays of cfDNA for clinical use in HTLV-1 carriers.

Neurofilament Light in CSF and Plasma Is a Marker of Neuronal Damage in HTLV-1-Associated Myelopathy and Correlates With Neuroinflammation

Background and Objectives

To evaluate the usefulness of CSF and plasma neurofilament light (Nf-L) as a biomarker for human T-cell lymphotropic virus type 1 (HTLV-1)-associated myelopathy (HAM).

Methods

Nf-L, CXCL10, and neopterin were measured by ELISA in 83 CSF samples obtained from 49 individuals living with HTLV-1/2. Plasma Nf-L was also measured by single molecule array. Results were correlated with duration of disease, age, mobility, CSF cell counts, CSF protein, and HTLV-1 proviral load.

Results

Nf-L was detected in all CSF samples (median [range] = 575 [791.8–2,349] pg/mL) and positively correlated with markers of inflammation (CXCL10 (r = 0.733), neopterin (r = 0.499), cell count (r = 0.403), and protein levels (r = 0.693) in CSF; p < 0.0015). There was an inverse correlation between Nf-L and duration of disease (r = −0.584, p < 0.0001). Wheelchair-dependent patients had high concentrations of markers of inflammation and neuronal damage. Concentrations of CXCL10, neopterin, and Nf-L remained elevated in follow-up samples (mean follow-up 5.2 years). Nf-L in plasma correlated with concentration of Nf-L, neopterin, CXCL10, and protein in CSF.

Conclusions

Nf-L in plasma and CSF has potential to be used as a biomarker of disease activity in HAM. Neuronal damage seems to be more intense early in disease but persists long term. Wheelchair-dependent patients have ongoing neuroinflammation.

Effect of Pulsed Methylprednisolone on Pain, in Patients with HTLV-1-Associated Myelopathy

HTLV-1-associated myelopathy/tropical spastic paraparesis (HAM/TSP) is an immune mediated myelopathy caused by the human T-lymphotropic virus type 1 (HTLV-1). The efficacy of treatments used for patients with HAM/TSP is uncertain. The aim of this study is to document the efficacy of pulsed methylprednisolone in patients with HAM/TSP. Data from an open cohort of 26 patients with HAM/TSP was retrospectively analysed. 1g IV methylprednisolone was infused on three consecutive days. The outcomes were pain, gait, urinary frequency and nocturia, a range of inflammatory markers and HTLV-1 proviral load. Treatment was well tolerated in all but one patient. Significant improvements in pain were: observed immediately, unrelated to duration of disease and maintained for three months. Improvement in gait was only seen on Day 3 of treatment. Baseline cytokine concentrations did not correlate to baseline pain or gait impairment but a decrease in tumour necrosis factor-alpha (TNF-α) concentration after pulsed methylprednisolone was associated with improvements in both. Until compared with placebo, treatment with pulsed methylprednisolone should be offered to patients with HAM/TSP for the treatment of pain present despite regular analgesia.

Biological function of the rotavirus protein VP4: observations on porcine isolates from China

Rotaviruses isolated from pigs in China were grown in MA104 cells. One tissue-culture-adapted isolate consisted of two subpopulations (variants), the RNA profiles of which differed in the relative migration of RNA segment 4 only. The variants were separated by plaque purification and by recovery from limiting dilutions and remained genetically stable. The variant possessing the slower migrating RNA segment 4, called 4S, grew faster and formed large plaques after 4-6 days incubation, whereas the variant possessing the faster migrating RNA segment 4, called 4F, grew more slowly and formed only microscopic plaques after 10-14 days incubation. The protein product of the 4F RNA occurred in much lower concentration in infected cells than the product of the 4S RNA. The RNA segments 4 of the two variants were found to be closely related when tested by dot hybridization under stringent conditions. The 4S RNA is more resistant to denaturation with methyl mercuric hydroxide than is the 4F RNA. The relevance of these findings to the biological functions of rotaviruses is discussed.

Maternal serum thyroid antibodies in early pregnancy and fetal Down's syndrome

Thyroid antibodies were measured in mid-trimester antenatal serum samples from 77 pregnancies affected by fetal Down's syndrome and 385 unaffected control pregnancies. Using a haemagglutination technique, thyroglobulin antibodies were detected in 5.2 per cent of cases (4) and 2.9 per cent of controls (11), and thyroid microsomal antibodies were detected in 22 per cent (17) and 15 per cent (59), respectively. Using an enzyme-linked immunosorbent assay (ELISA) for thyroglobulin antibodies and a cut-off level of 50 KIU/l, positive results were found in 25 per cent of cases (19) and 22 per cent of controls (84). Using an ELISA for thyroid microsomal antibodies and the same cut-off level, the proportions were 52 per cent (40) and 39 per cent (149), respectively. While not statistically significant, the differences were consistent with the previously reported increased levels of thyroid antibody found in non-pregnant women who had had pregnancies associated with Down's syndrome.