Victor H Jimenez-Zepeda

Low Counts of B Cells, Natural Killer Cells, Monocytes, Dendritic Cells, Basophils, and Eosinophils are Associated with Postengraftment Infections after Allogeneic Hematopoietic Cell Transplantation

Hematopoietic cell transplant (HCT) recipients are immunocompromised and thus predisposed to infections. We set out to determine the deficiency of which immune cell subset(s) may predispose to postengraftment infections. We determined day 28, 56, 84, and 180 blood counts of multiple immune cell subsets in 219 allogeneic transplant recipients conditioned with busulfan, fludarabine, and Thymoglobulin. Deficiency of a subset was considered to be associated with infections if the low subset count was significantly associated with subsequent high infection rate per multivariate analysis in both discovery and validation cohorts. Low counts of monocytes (total and inflammatory) and basophils, and low IgA levels were associated with viral infections. Low plasmacytoid dendritic cell (PDC) counts were associated with bacterial infections. Low inflammatory monocyte counts were associated with fungal infections. Low counts of total and naive Bxa0cells, total and CD56(high) natural killer (NK) cells, total and inflammatory monocytes, myeloid dendritic cells (MDCs), PDCs, basophils and eosinophils, and low levels of IgA were associated with any infections (due to any pathogen or presumed). In conclusion, deficiencies of Bxa0cells, NK cells, monocytes, MDCs, PDCs, basophils, eosinophils, and/or IgA plasma cells appear to predispose to postengraftment infections.

Risk factors for post-transplant lymphoproliferative disorder after Thymoglobulin-conditioned hematopoietic cell transplantation

Epstein‐Barr virus (EBV)‐induced post‐transplant lymphoproliferative disorder (PTLD) occurs frequently when rabbit antithymocyte globulin (ATG) is used in hematopoietic cell transplant (HCT) conditioning. We retrospectively studied 554 patients undergoing ATG‐conditioned myeloablative HCT. Strategies used to minimize mortality due to PTLD were either therapy of biopsy‐diagnosed PTLD in the absence of EBV DNAemia monitoring (n = 266) or prompt therapy of presumed PTLD (based on clinical/radiologic signs and high EBV DNAemia, in the setting of weekly EBV DNAemia monitoring) (n = 199). Both strategies resulted in similar mortality due to PTLD (0.7% vs 1% at 2 years, P = .43) and similar overall survival (63% vs 67% at 2 years, P = .23) even though there was a trend toward higher PTLD incidence with the prompt therapy. Donor positive with recipient negative EBV (D+R−) serostatus was a risk factor for developing PTLD. Older patient age, HLA‐mismatched donor, and graft‐versus‐host disease were not associated with increased risk of PTLD. In summary, in ATG‐conditioned HCT, D+R− serostatus, but not older age, mismatched donor or GVHD is a risk factor for developing PTLD. EBV DNAemia monitoring may be a weak risk factor for developing/diagnosing PTLD; the monitoring coupled with prompt therapy does not improve survival.

Co-existent B-cell and plasma cell neoplasms: a case series providing novel clinical insight

Concomitant plasma cell (PCN) and B-cell neoplasms (BCN) in a single patient have been infrequently reported. This study reviewed nine such patients at the institution – six had multiple myeloma (MM) associated with a BCN (MM/B group) and three had AL amyloidosis (ALA) with a BCN (ALA/B group). This study describes two syndromes of MM/B – three patients presented with CLL and subsequently developed MM, while three presented with MM and monoclonal B-cell lymphocytosis. In the ALA/B group, all three patients had systemic ALA and a BCN. Responses of the BCN and PCN to treatment correlated. In the two patients whose MM relapsed, the BCN simultaneously relapsed. The finding that the BCN may relapse in tandem with the MM argues against a coincidental relationship between the two.

A novel transthyretin variant p.H110D (H90D) as a cause of familial amyloid polyneuropathy in a large Irish kindred

Abstract Hereditary transthyretin (ATTR) amyloidosis is caused by inheritance of an abnormal TTR gene in an autosomal dominant fashion. In its native state, TTR is a homotetramer consisting of four identical polypeptides. Mutations in the TTR gene contribute to destabilization and dissociation of the TTR tetramer, enabling abnormally folded monomers to self-assemble as amyloid fibrils. Currently, over 120 TTR variants have been described, with varying geographic distributions, degrees of amyloidogenicity and organ involvement. We report here a large Irish family with familial amyloid polyneuropathy (FAP), consisting of multiple affected generations, caused by a novel TTR mutation; p.H110D (H90D). The demonstration, by immunohistochemistry and laser micro dissection–mass spectrometry (LMD/MS) that the amyloid fibrils were composed of TTR, in conjunction with a typical FAP phenotype, indicates that the novel TTR mutation was the cause of amyloidosis. We used a molecular visualization tool PyMOL to analyze the effect of the p.H110D (H90D) replacement on the stability of the TTR molecule. Our data suggest that the loss of two hydrogen bonds and the presence of an additional negative charge in the core of a cluster of acidic residues significantly perturb the tetramer stability and likely contribute to the pathogenic role of this variant.

Epstein-barr virus DNAemia monitoring for the management of post-transplant lymphoproliferative disorder

BACKGROUNDnPost-transplant lymphoproliferative disorder (PTLD) is a potentially fatal complication of allogeneic hematopoietic cell transplantation (HCT). Epstein-Barr virus (EBV) reactivation (detectable DNAemia) predisposes to the development of PTLD.nnnMETHODSnWe retrospectively studied 306 patients monitored for EBV DNAemia after Thymoglobulin-conditioned HCT to determine the utility of the monitoring in the management of PTLD. DNAemia was monitored weekly for ≥12 weeks post-transplantation.nnnRESULTSnReactivation was detected in 82% of patients. PTLD occurred in 14% of the total patients (17% of patients with reactivation). PTLD was treated with rituximab only when and if the diagnosis was established. This allowed us to evaluate potential DNAemia thresholds for pre-emptive therapy. We suggest 100,000-500,000u2009IU per mL whole blood as this would result in unnecessary rituximab administration to only 4-20% of patients and near zero mortality due to PTLD. After starting rituximab (for diagnosed PTLD), sustained regression of PTLD occurred in 25/25 (100%) patients in whom DNAemia became undetectable. PTLD progressed or relapsed in 12/17 (71%) patients in whom DNAemia was persistently detectable.nnnDISCUSSIONnIn conclusion, for pre-emptive therapy of PTLD, we suggest threshold DNAemia of 100,000-500,000u2009IU/mL. Persistently detectable DNAemia after PTLD treatment with rituximab appears to have 71% positive predictive value and 100% negative predictive value for PTLD progression/relapse.