Resolution of Primary Immune Defect in 22q11.2 Deletion Syndrome

Purpose

Patients with 22q11.2 deletion syndrome have a variable decrease in immunological parameters, especially regarding T cell counts. The aim of this study was to investigate immunological change over time and factors associated with immunological recovery among patients with 22q11.2 deletion syndrome.

Methods

Patients with 22q11.2 deletion syndrome diagnosed by fluorescence in situ hybridization (FISH) were studied. Immunological parameters were evaluated every 6 months until patients returned to normal. Infection and vaccination histories were recorded and analyzed, and Kaplan-Meier survival curves were plotted to describe resolution of immunodeficiency.

Results

Forty-nine patients with an age range of 4 to 222 months were included. Twenty-five (51%) patients were female. In hypocalcemia, the odds ratio for CD4 lymphopenia was 17.03 (95%CI 1.82–159.23; p value = 0.01). Thirty patients (61.2%) exhibited decreased CD4+ T cell numbers, which returned to normal level in 18 (60%) patients. Median age of CD4+ T cell resolution was 2.5 years. T cell functions were abnormal in three patients. T cell functions returned to normal in all patients at a median age of 1.1 years. Six patients (13.5%) had abnormal serum immunoglobulin levels, with levels improving in four patients at 1.4 years of age. The most common infection was pneumonia (69.4%). BCG vaccination was administered in 47 of 49 patients at birth. Among 32 patients who had T cell defect, one patient developed BCGitis and one developed disseminated BCG.

Conclusion

Immunodeficiencies identified among patients with 22q11.2 deletion syndrome were T cell defect (65.3%) and decreased immunoglobulin levels (12.2%). Median age of CD4 resolution was 2.5 years.

     

Clinicopathological study of experimentally induced canine monocytic ehrlichiosis

The aims of this study are to investigate the hematology, blood chemistry, pathological study, including macroscopic and microscopic lesions, of experimentally induced canine monocytic erhlichiosis in Thailand and to demonstrate the distribution of Ehrlichia canis in target organs by nested polymerase chain reaction (PCR). Five experimental healthy dogs were inoculated with 5 ml of whole blood (estimated number of E. canis morulae 15 × 10^–5% per monocytes) from the splenectomized dog via the saphenous vein. Two healthy dogs served as a negative control. Hematology revealed nonregenerative normocytic normochromic anemia, thrombocytopenia and mild leukopenia. Blood chemistry revealed an increase in aspartate aminotransferase (AST), alanine aminotransferase (ALT) and alkaline phosphatase (AP), hypoproteinemia, hypoalbuminemia, and hyperglobulinemia by day 66 post-inoculation. Pathology revealed anemia, ascites, jaundice, interstitial pneumonia, splenomegaly, generalized lymphadenopathy, and severe fatty liver. The detection of E. canis was performed using tissue embedded in paraffin wax by nested PCR showing positive in all target organs. This study concluded that acute induced experimental canine monocytic ehrlichiosis can cause significant clinical and pathological lesions.     

Coinfection with three Ehrlichia species in dogs from Thailand and Venezuela with emphasis on consideration of 16S ribosomal DNA secondary structure

As part of a larger study to investigate tick-borne infections in dogs from Thailand and Venezuela, documentation of coinfection with three Ehrlichia species in two dogs, one from each country, became the focus of the present study. Although neither dog had clinical signs attributable to ehrlichiosis, both dogs were anemic and neutropenic and the Thai dog was thrombocytopenic. Genus- and species-specific PCR targeting the 16S rRNA genes indicated that both dogs were coinfected with Ehrlichia canis, E. platys, and E. equi. To our knowledge, these results provide the first molecular documentation for the presence of E. equi in dogs from these countries. Using universal bacterial PCR primers, one nearly full-length 16S rRNA gene could be amplified from each dog. The sequences were identical to each other and almost identical to that of E. platys (AF156784), providing the first E. platys 16S ribosomal DNA (rDNA) sequences reported from these two geographically divergent countries. To determine whether these sequence differences allow differentiation between these two strains and other published 16S rDNA E. platys sequences, we performed a phylogenetic analysis of the rRNA, incorporating the consideration of secondary structure.     

Molecular characterization of Thai Ehrlichia canis and Anaplasma platys strains detected in dogs.

Canine monocytic ehrlichiosis caused by Ehrlichia canis is of veterinary importance worldwide. In Thailand, there has been little information available on E. canis and its phylogeny. The objective of this study was to characterize and establish molecular structure and phylogeny of Thai Ehrlichia and Anaplasma strains. Genus-specific primers for Ehrlichia and Anaplasma were used to amplify the 16S rRNA gene from naturally infected canine blood samples, and these amplicon sequences were compared with other sequences from GenBank. Both homology and secondary structure analysis of 16S rRNA sequences indicated that they were novel E. canis and A. platys strains. Phylogenetic analysis revealed that the Thai E. canis strain was closely related and formed a single cluster with E. canis from different countries. A. platys found in this study showed close relationship with earlier report of A. platys from Thailand. To our knowledge this report represents the first molecular characterization of the nearly complete 16S rRNA gene from E. canis in dogs from Thailand.     

Molecular Detection and Identification of Bartonella Species in Rat Fleas from Northeastern Thailand

The presence of Bartonella species in Xenopsylla cheopis fleas collected from Rattus spp. (R. exulans, R. norvegicus, and R. rattus) in Khon Kaen Province, Thailand was investigated. One hundred ninety-three fleas obtained from 62 rats, were screened by polymerase chain reaction using primers specific for the 16S–23S intergenic spacer region, and the presence of Bartonella DNA was confirmed by using the citrate synthase gene. Bartonella DNA was detected in 59.1% (114 of 193) of fleas examined. Sequencing demonstrated the presence of Bartonella spp. similar to B. elizabethae, B. rattimassiliensis, B. rochalimae, and B. tribocorum in the samples tested with a cutoff for sequence similarity ≥ 96% and 4 clustered together with the closest match with B. grahamii (95.5% identity). If X. cheopis proves to be a competent vector of these species, our results suggest that humans and animals residing in this area may be at risk for infection by several zoonotic Bartonella species.Bartonella species are small, pleomorphic, gram-negative bacteria that infect a variety of mammalian hosts, including cats, dogs, rodents, ruminants, and humans. Clinical symptoms associated with Bartonella range from mild, influenza-like symptoms to more severe manifestations such as endocarditis, myocarditis, uveitis, bacillary angiomatosis, and peliosis hepatis.¹ Approximately half of the 20 Bartonella species or subspecies identified to date are known or suspected human pathogens,² and most are believed to be transmitted by arthropod vectors (fleas, lice, sandflies, and ticks).³Xenopsylla cheopis, the Oriental rat flea, is a suspected vector of several Bartonella species (B. tribocorum, B. elizabethae, B. queenslandensis, B. rochalimae, and novel Bartonella genotypes), and Bartonella DNA has been detected in these fleas from various locations worldwide.^3–8 Although generally found on rodents, X. cheopis have been found to parasitize humans and are known vectors of the zoonotic agents Yersinia pestis (plague) and Rickettsia typhi (murine typhus).⁹Numerous surveys have been performed to identify the presence of Bartonella species affecting humans and domestic and peri-domestic animals in Thailand.^10–17 Bartonella henselae, (the agent of cat scratch disease),¹⁴ B. tamiae,¹⁰ B. elizabethae, B. rattimassiliensis, and B. tribocorum have been isolated from febrile patients,¹⁵ B. henselae and B. clarridgeiae have been reported in cats,¹¹ and B. clarridgeiae, B. vinsonii subsp. arupensis, B. elizabethae, B. grahamii, B. quintana, B. taylorii, and novel Bartonella genotypes have been found in dogs.^11,16 In rodent species, B. grahamii, B. elizabethae, Candidatus Bartonella thailandensis, B. coopersplainensis, B. phoceensis, B. rattimassiliensis, B. tribocorum, and novel Bartonella genotypes have been detected by culture and polymerase chain reaction (PCR) analysis.^12,13,17 However, little information has been obtained to identify potential arthropod vectors of Bartonella species in Thailand. Bartonella henselae, B. clarridgeiae and B. koehlerae were detected in Ctenocephalides felis fleas removed from cats^18–20 and B. henselae was identified in two C. canis¹⁹ also collected from cats. Furthermore, a Bartonella sp., similar to B. grahamii, was found in a rodent flea, Nosopsyllus fasciatus, obtained from Rattus surifer.¹⁸ Bartonella tamiae DNA has also been found in chigger mites (genera Leptotrombidium, Schoengastia, and Blankarrtia) and in a tick (genus Haemaphysalis) collected from rodents in Thailand, suggesting a potential role for these arthropods in the transmission of B. tamiae.²¹The aim of the current study was to investigate the prevalence of Bartonella species in rodent-associated fleas collected in Khon Kaen Province, Thailand, and to determine what potential role, if any, these fleas may play in the transmission of Bartonella species to individuals residing in this area.For this study, 62 rats (10 R. norvegicus, 9 R. rattus, and 43 R. exulans) were trapped in and around homes in 4 villages, 1 market, and on farm land (a pig farm and 2 rice fields) in Khon Kaen Province, Thailand during May–June 2011 (22 Work involving rodents was conducted as outlined in our approved animal use protocol (#11-003), under the supervision of the Institutional Animal Care and Use Committee of the Division of Vector Borne Diseases.

Table 1

Number of rats trapped per site by species and total number of fleas examined per site, northeastern Thailand