Occurrence of phenotypic abnormalities in CD34þ hematopoietic progenitor and precursor cells (HPC) and their major B-cell and nonlymphoid compartments has been frequently reported in myelodysplastic syndromes (MDS). Here, we analyze for the first time the numerical and phenotypic abnormalities of different maturation-associated subsets of bone marrow (BM) CD34þ HPC from 50 newly diagnosed MDS patients in comparison to normal/reactive BM (n ¼ 29). Our results confirm the existence of heterogeneously altered phenotypes among CD34 þ HPC from MDS and indicate that such variability depends both on the relative distribution of the different subsets of CD34 þ HPC committed into the different myeloid and B-lymphoid compartments, and their immunophenotype (for example, higher reactivity for CD117 and CD13 and lower expression of CyMPO, CD64 and CD65 on CD34 þ immature and neutrophil precursors), a clear association existing between the accumulation of CD34 þ HPC and that of immature CD34 þ HPC. Interestingly, expansion of erythroidand neutrophil-lineage CD34 þ cells is detected in low-grade MDS at the expense of CD34 þ plasmacytoid dendritic cell and B-cell precursors, while expansion of immature CD34 þ precursors occurs in high-grade MDS. On the basis of the number and severity of the phenotypic abnormalities detected, a scoring system is proposed that efficiently discriminates between normal/reactive and MDS CD34 þ HPC, the mean score significantly increasing from low-to high-grade MDS.

Immunophenotypic characterization of B-cell chronic lymphoproliferative disorders (B-CLPD) is becoming increasingly complex due to usage of progressively larger panels of reagents and a high number of World Health Organization (WHO) entities. Typically, data analysis is performed separately for each stained aliquot of a sample; subsequently, an expert interprets the overall immunophenotypic profile (IP) of neoplastic B-cells and assigns it to specific diagnostic categories. We constructed a principal component analysis (PCA)-based tool to guide immunophenotypic classification of B-CLPD. Three reference groups of immunophenotypic data files—B-cell chronic lymphocytic leukemias (B-CLL; n=10), mantle cell (MCL; n=10) and follicular lymphomas (FL; n=10)—were built. Subsequently, each of the 175 cases studied was evaluated and assigned to either one of the three reference groups or to none of them (other B-CLPD). Most cases (89%) were correctly assigned to their corresponding WHO diagnostic group with overall positive and negative predictive values of 89 and 96%, respectively. The efficiency of the PCA-based approach was particularly high among typical B-CLL, MCL and FL vs other B-CLPD cases. In summary, PCA-guided immunophenotypic classification of B-CLPD is a promising tool for standardized interpretation of tumor IP, their classification into well-defined entities and comprehensive evaluation of antibody panels.

Background: Since limited data on superficial fungal infections in teenagers exist in our setting, this study provides the first description of the clinical and epidemiological characteristics of these infections among teenagers in Lima and Callao, Peru. Methodology: The study involved 1,387 adolescents in five public schools from June to November 2006. Participants were examined for superficial fungal lesions. Samples of skin scrapings for microbiological investigations were obtained from suspicious lesions. Results: A total of 257 subjects were identified with suspected superficial fungal infections. Microbiological assessment was positive for 166 of 257 (64.59%). The average prevalence was 12.61% with variation between different districts. Males were more affected (64%) than females (36%) (p = 0.001). Pet ownership, use of public baths, and wearing sneakers were identified as important risk factors. The majority (61.5%) of the subjects presented with itching although 38.5% were asymptomatic. Tinea pedis was observed in 62.6%, onychomycosis in 24% and pityriasis versicolor in 10.8%. Dermatophytes were isolated in 105 cases with T. rubrum being identified in 86 cases (59.7%), T. mentagrophytes in 14 (9.7%) and yeast in 39 (23.4%). Malassezia spp. was found by direct examination in 18 cases (12.5%), C. kruseii in 8 cases (5.6%), and C. albicans in 2 cases (1.4%). Mixed infections were found in 22 cases. Conclusions: Superficial fungal infection manifesting as tinea pedis, onychomycosysis and tinea ver sicolor is prevalent in our setting. As many infections remain asymptomatic, regular examination of this population is advocated. The associated risk fac tors for these infections also need to be addressed.