Multi-organ IgG4-related disease: Demystifying the diagnostic enigma

IgG4-related disease (IgG4-RD) is a multisystemic mass forming immune-mediated disease entity, commonly creating confusion and diagnostic challenges. We present a case of a 25-year-old female who presented with bilateral orbital masses, lymphadenopathy, paraspinal and renal masses, which clinicoradiologically simulated lymphoma. The lymph node biopsy revealed interfollicular sheets of plasma cells creating confusion with Castleman's disease and marginal zone lymphoma. The orbital biopsy revealed ductular destruction, periductular plasma cells, and fibrosis, mimicking Sjogren's syndrome and Castleman's disease. However, the correlation of the clinical features with histopathological findings, IgG4 immunopositivity, and serum studies helped in clinching the diagnosis. This case presents an uncommon combination of clinical features infrequently reported in literature. Furthermore, and more importantly, it highlights the need to keep a differential of IgG4-RD in mind, to aid early and correct treatment of the disease.

Identification of genetic variation in NOD-like receptor 2 gene and influence of polymorphism on gene structure and function in buffalo (Bubalus bubalis)

Nucleotide-binding oligomerization domain (NOD)-like receptor 2 is one of the important mediators of innate as well as adaptive immune response to microbial infections. In this study, NOD-like receptor-2 was characterized by determining the full gene sequence and analyzing genetic diversity in Indian buffaloes. Sequence analysis of buffalo NOD2 revealed 3042 nucleotides long ORF, encoding 1013 amino acids from 12 exons. Domain structure analysis indicated existence of 8 leucine-rich repeat (LRR) domains in buffalo, cattle, sheep and mouse, along with central NACHT/NOD domain and two N-terminal CARD domains. Comparative sequence analysis among different buffalo breeds identified 46 polymorphic sites in NOD2 gene. Among coding region SNPs, 10 were non-synonymous, 7 synonymous and 3 were present in 5'UTR. Genotyping of two nsSNPs, revealed significant differences in the allele frequencies, distinguishing swamp and riverine buffaloes, having different utilities. Association analysis with mastitis in dairy buffaloes indicated significant variation in allelic frequencies at G1135A locus, between mastitis affected and non-affected animals. Further, NOD2 gene expression was quantified in different riverine buffalo tissues, using real-time PCR and lymph node displayed highest expression, compared to others organs included in the study. Overall, the study revealed buffalo NOD2 gene attributes, important to understand species specific immune response in ruminants.

Expression Analysis of Genes Associated with Prolificacy in FecB Carrier and Noncarrier Indian Sheep

The effect of FecB mutation on the gene expression in FecB carrier and noncarrier estrous synchronized ewes, has been analyzed. For this study the whole ovarian tissues and Graafian follicles were collected from estrus synchronized FecB carrier Garole, and non-carrier Deccani Indian sheep, showing remarkable differences in the numbers of preovulatory follicles among two groups. Eleven potential candidate genes (BMP15, GDF9, BMP4, BMP7, BMPR1B, BMPR1A, SMAD9, LHCGR, FSHR, IGF1R, and STAT5) were selected for their expression analysis by SybrGreen based real-time PCR, across ovaries and Graafian follicles of different fecundity groups, for having better insights into the effect of FecB genotypes on follicular development. Variable expression was observed for almost all the genes included in the present study among high and low fecundity groups that was most significant for the BMP7, BMP4, LHCGR, and FSHR transcripts in the ovarian follicles of high and low fecundity ewes, indicating their importance in governing the fecundity in FecB carrier, Indian Garole sheep. BMP4 expression among the genes studied was significantly higher in FecB carrier Garole sheep. This study confirms the changes in mRNA expression of the genes implicated in follicular development in FecB carrier and noncarrier Indian sheep breeds.

Herpes Zoster in Autologous Hematopoietic Cell Transplant Recipients in the Era of Acyclovir or Valacyclovir Prophylaxis and Novel Treatment and Maintenance Therapies

The epidemiology of herpes zoster (HZ) in contemporary autologous hematopoietic cell transplant (HCT) recipients, and the impact of acyclovir (ACV)/valacyclovir (VACV) prophylaxis, is not well described. In this observational study from 2002 to 2010, we retrospectively identified 1000 varicella zoster virus (VZV)-seropositive autologous HCT recipients with up to 5 years of follow-up. The incidence of HZ and use of ACV/VACV prophylaxis were determined through review of medical records and mailed questionnaires. Risk factors for HZ were determined by multivariable Cox regression. Over a period of 5 years after autologous HCT, 194 patients developed at least 1 HZ episode, with a cumulative incidence of 21%; 159 of 194 (82%) were not on prophylaxis at the time of HZ. A second episode of HZ occurred in 31 of 194 (16%) patients. Patients taking ACV/VACV had reduced risk for HZ (adjusted hazard ratio [aHR], .59; 95% confidence interval [CI], .37 to .91), whereas those older than the median age (≥55.5 years) had increased risk (aHR, 1.42; 95% CI, 1.05 to 1.9). Disseminated VZV was reported in 8% and postherpetic neuralgia in 13% of patients. We demonstrate a high burden of HZ late after autologous HCT, despite long-term antiviral prophylaxis. Improved prevention strategies are needed to provide sustained protection against HZ after autologous HCT.

Rapid detection of rifampicin resistance in Mycobacterium tuberculosis by high-resolution melting curve analysis

SETTING

High-resolution melting curve analysis (HRMA) can be used to screen for mutations in genes without the need for specific probes, with low turnaround time and high cost-effectiveness.

OBJECTIVE

To detect the sensitivity and specificity of a line-probe assay (LPA) and HRMA in comparison with BACTEC™ MGIT™ 960 for the detection of rifampicin (RMP) resistance.

DESIGN

A total of 219 Mycobacterium tuberculosis isolates tested by MGIT 960 for RMP susceptibility were tested with HRMA and LPA. Discordant samples were processed for sequencing of the RMP resistance-determining region (RRDR) of the rpoB gene.

RESULTS

HRMA identified 93 of 103 (90.3%) isolates that were resistant and 113/116 (97.4%) that were susceptible on MGIT 960, with a sensitivity and specificity of respectively 90.3% and 97.4%. HRMA identified 117/119 (98.3%) LPA-susceptible and 94/100 (94%) resistant isolates, with 98.3% specificity and 94% sensitivity. Two isolates that were susceptible on LPA but resistant on HRMA showed silent mutations at 539 and 541 codons on sequencing, while 6 isolates that were susceptible on HRMA but resistant on LPA showed D516V (n = 4) and H526C/D (n = 2) mutations. Four isolates (3.9%) that were resistant on MGIT were susceptible on all three genotypic methods, which could be due to mutations outside the RRDR or efflux pumps.

CONCLUSION

HRMA shows good potential as a rapid screening tool for the detection of drug resistance.

Molecular Characterization of Buffalo Haptoglobin: Sequence Based Structural Comparison Indicates Convergent Evolution Between Ruminants and Human

Haptoglobin (Hp) protein has high affinity for hemoglobin (Hb) binding during intravascular hemolysis and scavenges the hemoglobin induced free radicals. Earlier reports indicate about uniqueness of Hp molecule in human and cattle, but in other animals, it is not much studied. In this paper, we characterized buffalo Hp molecule and determined its molecular structure, evolutionary importance, and tissue expression. Comparative analysis and predicted domain structure indicated that the buffalo Hp has an internal duplicated region in α-chain only similar to an alternate Hp2 allele in human. This duplicated part encoded for an extra complement control protein CCP domain. Phylogenetic analysis revealed that buffalo and other ruminants were found to group together separated from all other non-ruminants, including human. The key amino acid residues involved in Hp and Hb as well as Hp and macrophage scavenger receptor, CD163 interactions in buffalo, depicted a significant variation in comparison to other non-ruminant species. Constitutive expression of Hp was also confirmed across all the vital tissues of buffalo, for the first time. Results revealed that buffalo Hp is both structurally and functionally conserved, having internal duplication in α-chain similar to human Hp2 and other ruminant species, which might have evolved separately as a convergent evolutionary process. Furthermore, the presence of extra Hp CCP domain possibly in all ruminants may have an effect during dimerization of molecule in these species.

Inverted papilloma of the hard palate masquerading as a carcinoma

Inverted papilloma (IP) is a rare, benign tumor of the nose and paranasal sinus. However, it is locally aggressive, the recurrence rate is high and malignant transformation is possible. Until now, IP of the hard palate has rarely been reported in the literature. Here, we reported a case with IP of the hard palate, which clinically presented as a carcinomatous growth. The management of IP is complete surgical excision with a close follow-up to detect early recurrence and/or malignant transformation.

Cytomegalovirus viral load and mortality after haemopoietic stem cell transplantation in the era of pre-emptive therapy: a retrospective cohort study

BACKGROUND

Although cytomegalovirus viral load is commonly used to guide pre-emptive therapy in the post-transplantation setting, few data are available correlating viraemia with clinical endpoints. We therefore investigated the association between cytomegalovirus viral load and mortality in the first year after haemopoietic stem cell transplantation.

METHODS

In this retrospective cohort study, we included patients from the Fred Hutchinson Cancer Research Center, WA, USA, who received an allogeneic haemopoietic stem cell transplantation between Jan 1, 2007, and Feb 28, 2013, were cytomegalovirus seropositive or had a seropositive donor, and underwent weekly plasma cytomegalovirus monitoring by PCR through to day 100 post-transplantation. Cox proportional hazards models were used to estimate the association of cytomegalovirus viral load at different thresholds with overall mortality by 1 year post-transplantation, adjusting for the use of pre-emptive therapy and other factors such as neutropenia, and graft-versus-host disease.

FINDINGS

Of the 1037 patients initially selected for inclusion in this cohort, 87 (8%) patients were excluded because of missing cytomegalovirus testing and 24 (2%) were excluded because of their participation in cytomegalovirus prophylaxis trials. In the remaining 926 patients included in this study, the cumulative overall mortality was 30·0% (95% CI 26·9-33·0) 1 year after haemopoietic stem cell transplantation. 95 patients developed cytomegalovirus disease; death was directly attributable to cytomegalovirus disease in three (1%) of 263 patients who died in the first year after transplantation. A cytomegalovirus viral load of 250 IU/mL or greater was associated with increased risk of early (day 0-60 post-transplantation) death (adjusted hazard ratio [HR] 19·8, 95% CI 9·6-41·1). The risk was attenuated after day 60 (adjusted HR 1·8, 95% CI 1·3-2·3). Similar associations were noted for higher cytomegalovirus viral load thresholds.

INTERPRETATION

Cytomegalovirus viraemia is associated with an increased risk of overall mortality in the first year after haemopoietic stem cell transplantation, independent of the use of pre-emptive therapy, and with evidence of a positive dose-response relationship. These data indicate the suitability of viral load as a surrogate clinical endpoint for clinical trials for cytomegalovirus vaccines, biologics, and drugs.

FUNDING

Merck and Co, National Institutes of Health.

Confirmation of TTC8 as a disease gene for nonsyndromic autosomal recessive retinitis pigmentosa (RP51)

Nonsyndromic retinitis pigmentosa (RP) is genetically highly heterogeneous, with >100 disease genes identified. However, mutations in these genes explain only 60% of all RP cases. Blood samples were collected from 12 members of an autosomal recessive RP family. Whole genome homozygosity mapping and haplotype analysis placed the RP locus in this family at chromosome 14q31.3. Whole-exome sequencing (WES) in proband revealed a mutation in TTC8, which was flagged as most likely candidate gene by bioinformatic analysis. TTC8 is mutated in Bardet-Biedl syndrome 8 (BBS8), and once reported previously in a family with nonsyndromic RP. Sequencing of amplified products of exon 13 of TTC8 validated c.1347G>C (p.Gln449His), a novel change that affects the final nucleotide of exon 13 and might deleteriously affect splicing. This mutation segregated completely with the disease in the family and was not observed in 100 ethnically matched controls from same population. This represents second report of a TTC8 mutation in nonsyndromic RP, thus confirming the identity of TTC8 as causative gene for RP51.