Microvillus inclusion disease (MVID), a rare severe congenital enteropathy characterized by intracytoplasmic microvillous inclusions and variable brush border atrophy on intestinal epithelial cells histology, is associated with defective synthesis or abnormal function of the motor protein myosin Vb encoded by the MYO5B gene. Although MYO5B gene is expressed in all epithelial tissues, it is unclear so far whether organs other than intestine are affected in MVID patients. We report a case of an infant with MVID who presented liver dysfunction, hematuria, and Pneumocystis jiroveci pneumonia during the course of the disease. It is discussed whether extraintestinal manifestations in this patient are secondary consequences of MVID or might be features of the disease associated with altered MYO5B function. Conclusions: MVID is classically included in the differential diagnosis of congenital diarrhea of secretory type. Recent advances in our knowledge regarding the role of myosin Vb in the pathophysiology of MVID is expected to clarify the clinical spectrum of the disease and the possible primary involvement of organs other than intestine.

BACKGROUND: Neonatal immune neutropenia (NIN) is a rare, but potentially life-threatening, disorder caused by maternal alloantibodies recognizing paternal neutrophil antigens on fetal cells. Alloantibodies directed against the human neutrophil alloantigen system (HNA)-1 located on Fcγ receptor IIIb (FcγRIIIb) are most frequently implicated in NIN. In this report, we describe two cases of NIN with alloantibodies against FcγRIIIb, which did not match one of the known HNA-1a, -1b, or -1c specificities, but define a new antigen, HNA-1d. STUDY DESIGN AND METHODS: Neutrophil-reactive antibodies were detected by agglutination, microscopic immunofluorescence, and monoclonal antibody (MoAb)-specific immobilization of neutrophil antigens (MAIGA) assay. For epitope mapping of FcγRIIIb-reactive antibodies, recombinant chimeric variants of FcγRIIIb were used in the MAIGA assay. Genotyping of FCGR3B was performed by allele-specific polymerase chain reaction. RESULTS: Both mothers were typed FCGR3B*01+, *02-, *03+. Antibody screening revealed the presence of alloantibodies reactive with FcγRIIIb encoded by FCGR3B*02, but not with FcγRIIIb encoded by FCGR3B*03. MAIGA with recombinant, partly chimeric FcγRIIIb variants demonstrated that the antigen recognized by maternal antibodies is characterized by two amino acids, Ala78 and Asp82. Among the FCGR3B alleles, the sequence Ala78–-Asn82 is exclusively encoded by FCGR3B *02. CONCLUSION: A previously unrecognized second antigen, HNA-1d, is present on FcγRIIIb encoded by FCGR3B*02. This antigen is characterized by the sequence Ala78–-Asn82. It appears that only individuals carrying the HNA-1c phenotype can form anti-HNA-1d alloantibodies. The HNA-1 system now consists of four antigens encoded by three alleles.

BACKGROUND: Influenza is associated with an increased risk for serious illness, hospitalization, and mortality in infants aged <6 months. However, influenza vaccines are not licensed for administration in this age group. The study evaluated the effectiveness of postpartum influenza vaccination of mothers and household members in infants. METHODS: The influenza vaccine was offered to mothers and household members of neonates born or hospitalized in 3 hospitals prior to the 2012-2013 season. Mothers were contacted every 2 weeks during the influenza season, and data regarding the onset of fever and/or respiratory symptoms in infants, healthcare seeking, hospitalization, and administration of antibiotics were collected. RESULTS: The study group consisted of 553 mothers who delivered 573 neonates. The influenza vaccine was administered to 841 of 1844 (45.6%) household contacts. Vaccination coverage rates ranged between 41.9% for neonates siblings and 49% for mothers. Five hundred thirty infants were analyzed for vaccine effectiveness. For outcomes in the infant, postpartum maternal vaccination had 37.7% effectiveness against acute respiratory illness (ARI), 50.3% against a febrile episode, 53.5% against influenza-like illness (ILI), 41.8% against related healthcare seeking, and 45.4% against administration of antibiotics. Multiple logistic regression analyses showed that maternal influenza vaccination was significantly associated with a decreased probability for febrile episodes, ARIs, and/or ILIs in infants, related healthcare seeking, and/or administration of antibiotics during the influenza season. Vaccination of other household contacts had no impact. CONCLUSIONS: Maternal postpartum vaccination against influenza was associated with a significant reduction of influenza-related morbidity, healthcare seeking, and antibiotic prescription in infants during the influenza season.