RHCE and Kell genotyping and alloimmunization profile in patients with sickle cell disease in the Federal District of Brazil

INTRODUCTION

Sickle cell disease (SCD) is the most important hemoglobinopathy worldwide. The treatment often requires phenotype-matched red blood cell (RBC) transfusions, but alloimmunization to non-ABO antigens may occur in a part of the SCD patients. The genotyping has been used for RBC antigen prediction, reducing the possibility of the alloimmunization.

OBJECTIVE AND METHOD

In this study we performed the genotyping for the Kell and RHCE blood groups in samples from 77 phenotyped Brazilian SCD patients, whose alloimmunization profiles were also assessed.

RESULTS

Discrepancies between genotyping and phenotyping for the RHCE and Kell blood groups systems were observed in 22.07% (17/77) of the SCD patients. We found C/c and E/e discrepancies in 11.68% and 9.09% of patients, respectively; one SCD patient (1.3%) presented a discrepancy in the Kell group. Two SCD patients with discrepancies between genotype and phenotype were alloimmunized. In total, twenty-eight patients (36.4%) developed alloantibodies, of which 55.17% were directed against antigens in the Rh system, 8.62% were directed against antigens in the Kell system and 36.20%, against other groups. Finally, the frequency of discrepancies is significantly higher in non-alloimmunized patients (30.61%), compared to alloimmunized patients (7.14%) (p = 0.0217).

CONCLUSION

In part, the alloimmunization of the SCD patients may have been triggered by these discrepancies, indicating that the integration of serological and molecular tests in the immunohematology routine could help to increase the transfusion safety. However, the higher number of alloimmunized patients without discrepancies showed that reasons other than the discrepancies appear to have influenced more strongly the alloimmunization in the SCD patients in this study.

Epidemiologic analysis of clinical isolates of Pseudomonas aeruginosa from an university hospital

OBJECTIVES

Pseudomonas aeruginosa is an increasingly prevalent opportunistic pathogen in hospital infection cases. Its high resistance rates to many antimicrobials has given this microorganism a relevant role among other highly prevalent bacteria involved in nosocomial infections. This study aimed to analyze epidemiologic characteristics of P. aeruginosa and to evaluate its susceptibility to antimicrobial agents at Hospital das Clínicas of the Universidade Federal de Pernambuco

METHODS

A retrospective study was performed based on the registry book of miscellaneous secretions from the bacteriology laboratory of the Hospital das Clínicas involving the period between January and June 2008. Among the secretions registered, were identified the positives samples for P. aeruginosa, whose origin was analyzed, as well as its susceptibility profile to routinely used in our laboratory antimicrobials.

RESULTS

The bacteria most frequently isolated from miscellaneous secretions bacteria were P. aeruginosa (26%) and S. aureus (25%). P. aeruginosa was mainly isolated from respiratory infections, with 33% of positive samples for this organism from tracheal secretions and 21% from nasal. The most effective antimicrobials against P. aeruginosa were: amikacin, imipenem, meropenem and aztreonam.

CONCLUSIONS

These results show a high prevalence of P. aeruginosa in the Hospital das Clínicas of the Universidade Federal de Pernambuco. Despite featuring high resistance rates to older antimicrobials, as cephalosporins first and second generations and chloramphenicol, this pathogen showed good susceptibility to agents routinely used in this hospital.