Evidence for a higher resolution of HLA genotyping by a new NGS-based approach.

With more than 16,000 alleles identified, the human leucocyte antigen (HLA) system is one of the most polymorphic regions of the human genome. Regarding the crucial role of HLA compatibility in transplantation and especially in Hematopoietic Stem Cell Transplantation, identification of HLA polymorphisms at a high-resolution level is of major interest. Recently, NGS technology has been proposed which appears to be simpler and more informative than the classical molecular methods such as SSP, SSOr and SBT. In the present report, a new set of NGS reagents and the appropriate associated software for sequence analysis are described. Through different studies, the performances of the system are illustrated and demonstrate that the method herein described overcomes current limitations in performing high-resolution HLA typing in clinical laboratories.

Chronic lymphocytic leukemia: a hazardous condition before kidney transplantation.

Long-term survival of patients with chronic lymphocytic leukemia (CLL) is over 10 years, and such patients are thus potential kidney recipients in the case of superimposed end-stage renal disease. However, the renal and patient outcome in this condition is unknown. We report the charts of four patients with CLL who were engrafted in France with a deceased-donor kidney and underwent routine triple immunosuppressive therapy. The results show that these patients developed severe infectious episodes (fatal in one case) and tumoral complications including rapid progression of CLL in two cases. Moreover, the graft may be infiltrated and damaged by monoclonal B cells: one patient lost his graft 14 months after transplantation. Various therapeutic options (modifications of the immunosuppressive regimen, anti-CD20 antibodies, irradiation of the graft) showed little (if any) efficacy. Therefore, we believe that CLL is a too hazardous condition to envisage solid organ transplantation with a routine immunosuppressive regimen, and we propose a more appropriate approach.

[A cytological, immunophenotypical and cytogenetical study of 136 consecutive cases of B-cell chronic lymphoid hemopathies]. / Etude cytologique, immunophénotypique et cytogénétique d'une série de 136 cas consécutifs d'hémopathies lymphoïdes chroniques à cellules B matures.

A cytological, immunophenotypical and cytogenetical study of 136 chronic B-cell proliferations (93 CLL, 43 B-cell lymphomas) was led in order to precise diagnosis and to characterize and appreciate chromosomal rearrangements. In this series, mainly selected on blood lymphocytosis criteria, B-CLL were twice more frequent than small B-cell lymphomas. Probes used revealed cryptic abnormalities, which remained unknown by conventional cytogenetics (CC). The frequency of clonal abnormalities (CC and FISH) was 74.8% for this series, with 74.4% for lymphomas and 75.3% for CLL, mainly of Binet stage A (69 A, 13 B, 1 C, 10 unspecified). Proportion was 88.4% in A stages and 84.6% in B stages. In CLL, 13q14 cryptic deletions and translocations were widely majority, 14q32 translocations and trisomy 12 being predominant in lymphoma series. Interphase FISH study of non-clonal metaphasic abnormalities with locus-specific probes often revealed unrecognised clones.

Aberrant CD8 expression in B-chronic lymphocytic leukemia: report of five cases.

The expression of T cell-associated antigens on B cell non-Hodgkin lymphoma is rare. We describe 5 cases of B-chronic lymphocytic leukemia (B-CLL) with aberrant expression of CD8 on B cells. These B-CLL presented a typical immunophenotype CD19+, CD23+, FMC7- and CD5+ (except for 1 case) with a monotypic expression of surface immunoglobulin light chain kappa. The CD8 expression was confirmed on B-CLL cells by two-color flow cytometry staining. We could not find coexpression of CD3 or CD4 on B-CLL cells. The clinical implications, the sensitivity to therapy and the prognostic outcome of this aberrant expression remains to be determined.

Heterogenous expression of CD15 in acute lymphoblastic leukemia: a study of ten anti-CD15 monoclonal antibodies in 158 patients.

Discrepancies in the literature on acute leukemia blast cell immunophenotypes are sometimes related to differences between the epitopes recognized by various monoclonal antibodies (MoAb) in the same cluster of differentiation. CD15 is one example of such a variation. CD15 expression has been reported in 1.6% to 39% of acute lymphoblastic leukemias (ALL). We studied the expression of CD15 using 10 different commercially available anti-CD15 MoAbs and we observed three different expression patterns using anti-CD15 MoAbs by flow cytometry in 158 cases of ALL: Smy15c was found in 70% of B lineage ALLs, Smy15a and FMC-13 in 30 to 40% of cases and all others in less than 9% of B-ALL cases (p < 0.0001). In T lineage ALLs, Smy15c, Smy15a and FMC-10 identified CD15 in 30% of the cases and all others in less than 8% of the cases. Logistic regression revealed that Smy15a, CD34 and CD14 correlated significantly with Smy15c expression. We conclude that CD15 MoAbs have to be chosen carefully when ALL immunophenotype and subsequent studies of prognostic significance are performed particularly in assessing multiphenotypic ALLs.

Epidemiological characteristics of myelodysplastic syndrome in a well-defined French population.

Data on myelodysplastic syndromes (MDS) are seldom collected by cancer registries and unbiased findings from population-based studies remain rare. We report detailed information on MDS in a well-defined French population in the period 1980-1990. The crude incidence rate was 3.2 per 100000 per year and no significant change in incidence was noted in the study period. The sex ratio was 1.9 and the male predominance was present in all age groups. We observed a rise in incidence after 60 years of age but no significant change in incidence of MDS as a whole was observed over the period studied. Refractory anaemia with excess of blasts (RAEB) was the most frequent subtype. Overall 5 year transformation rate of MDS was 31% (+/- 4%) but it was 100% in RAEB in transformation. The observed 5 year survival rate was 23% +/- 3% and the corresponding corrected rate was 33%. The prognosis of RAEB in transformation was worse than the prognosis of other subtypes (P < 0.01). Discrepancies with epidemiological data from other European countries are discussed.