Molecular characterization of rare D--/D-- variants in individuals of Indian origin.

BACKGROUND: Rh antigens are critical in haemolytic disease of the foetus and newborn (HDFN). The D-- phenotype is a rare blood group characterised by the lack of expression of C, c, E and e antigens at the surface of red blood cells because of mutations in both RHCE alleles inactivating the expression of a "normal" protein. The aim of the study was to determine the molecular basis of D-- individuals of Indian origin. MATERIALS AND METHODS: Ten Rh D-positive postnatal women who had produced antibodies against all Rh antigens, except D, leading to HDFN and foetal loss, were investigated. Extensive serological and molecular (polymerase chain reaction [PCR] using sequence-specific primers), quantitative multiplex PCR of short fluorescent fragments (QMPSF), and Sanger sequencing analyses were carried out. RESULTS: Serological testing with anti-C, anti-c, anti-E, and anti-e reagents showed absence of the four antigens in all ten index cases, as well as in three siblings. Flow cytometry indicated absence of these antigens with a typical exalted expression of the D antigen, thus confirming the rare D-- phenotype. Molecular analysis by QMPSF suggested homozygous CE-D hybrid alleles causing the D-- phenotype: RHCE-D(3-9)-CE (n = 11), RHCE-D(3-8)-CE (n=1), and RHCE-D(2-6)-CE (n=1). DISCUSSION: For the first time, we report the molecular basis of the D-- phenotype in the Indian population. Identification and characterisation of RHCE-null variants by molecular methods can help resolve transfusion-related problems in these individuals. Family studies of index cases helped to identify rare blood donors and offer counselling to females of child-bearing age on the complications involved in such pregnancies.

Clinical Profile and Short Term Outcome of Children with Neutropenia.

OBJECTIVES: To study the clinical profile and short term outcome of neutropenia in children during hospital stay. METHODS: An observational study was carried out at a Children's Hospital. The study population comprised of 77 admitted children aged 1 mo to 18 y with a varied clinical profile and neutropenia; defined as absolute neutrophil count less than 1500/mm3. Patients known to have HIV, immunodeficiency, malignancy, aplastic anemia or chronic systemic illness were not enrolled. Necessary investigations were done to identify etiology as per clinical features. They were treated and followed up for a period of 4 wk or discharge; whichever was earlier. The primary outcome of duration of neutropenia and secondary outcomes of hospital stay duration, association with thrombocytopenia, incidence of complications and finally discharge/death were analyzed. RESULTS: Acute transient neutropenia was seen, the median duration being 3 d in younger patients. Dengue fever was the commonest etiology. The median duration of hospital stay was 8 d. Fifty three (68.8%) patients had associated thrombocytopenia. Three children developed complications like nosocomial sepsis and shock. Seventy two (93.5%) were discharged, 1 died, 3 left against medical advice and one patient was followed up for 4 wk. CONCLUSIONS: Acute febrile illnesses like dengue, enteric fever, malaria are the predominant causes of neutropenia. Mild neutropenia was seen in over 50% children requiring a short duration of admission (5-8 d); without any complications.