Ehrlichia and bone marrow cells: could Ehrlichial infection explain the unsuspected etiology of some diseases of the immune system?

Human granulocytotropic anaplasmosis-A systematic review and analysis of the literature

Human granulocytotropic anaplasmosis (HGA) is a zoonotic tick-borne bacterial infection caused by Anaplasma phagocytophilum. While most cases are reported from North America, HGA has been recognized as an emerging disease in several regions of the world in recent decades. Most available data comes from case reports, case series and retrospective studies, while prospective studies and clinical trials are largely lacking. To obtain a clearer picture of the currently known epidemiologic distribution, clinical and paraclinical presentation, diagnostic aspects, complications, therapeutic aspects, and outcomes of HGA, we systematically reviewed the literature and analyzed and summarized the data. Cases of HGA are reported from all continents except from Antarctica. HGA primarily presents as an unspecific febrile illness (88.5% of the cases) often accompanied by thrombocytopenia (71.8% of the cases), abnormal liver injury tests (66.7% of the cases), and leukopenia (49.8% of the cases). Although we found complications reported in a total of 40.5% of the reviewed cases and severe and even life-threatening complications are not infrequent (e.g. acute renal failure 9.8%, multi organ failure 7.5%, ARDS 6.3%, a.o.), sequelae are rare (2.1% of the cases) and lethality is low (3.0% of the cases). Treatment with doxycycline shows a rapid response, with the fever subsiding in the majority of patients within one day of starting treatment. Unlike in human monocytotropic ehrlichiosis (HME), reports of opportunistic infections complicating HGA are rare. HGA during pregnancy does not appear to be associated with unfavorable outcomes. In addition, our analysis provides some evidence that HGA may differ in clinical aspects and laboratory characteristics in different regions of the world. Overall, the data analyzed indicates a non-negligible bias in reporting/publication, so a certain degree of caution is required when generalizing the data.

ACHADOS HEMATOLÓGICOS EM SANGUE E MEDULA ÓSSEA DE CÃES NATURALMENTE INFECTADOS POR Ehrlichia spp. E Anaplasma spp

Resumo Objetivou-se analisar os achados hematológicos em sangue periférico e medula óssea em cães infectados por Ehrlichia spp. e Anaplasma spp.. Avaliaram-se 44 cães com suspeita clínica de hemoparasitose, de diferentes raças, idades e de ambos os sexos, submetidos ao exame sorológico pelo SNAP Test, a análises hematológicas e mielograma. Dos 44 cães avaliados, 63,6% (28/44) foram sorologicamente reagentes, sendo 57,1% (16/28) positivos para Ehrlichia spp., 21,4% (6/28) para Anaplasma spp. e 21,4% (6/28) de coinfectados. A trombocitopenia foi a alteração hematológica mais frequente em cães positivos para Ehrlichia spp., presente em 93,7% (15/16) (p=0,015) dos animais, enquanto a anemia macrocítica e hipocrômica prevaleceu em 66,7% (4/6) (p=0,010) dos animais infectados por Anaplasma spp.. Ao mielograma, 62,5% (10/16) (p=0,005) dos animais positivos para Ehrlichia spp. apresentaram hipoplasia medular e 75,0% (12/16) (p=0,044) diminuição do índice mieloide:eritroide (M:E). Nos animais positivos para Anaplasma spp., destacou-se a hiperplasia da série eritroide em 50,0% (3/6) (p=0,022) dos cães. Não houve associação significativa em nenhuma das análises com o grupo coinfecção (p>0,05). Os resultados obtidos neste estudo permitem inferir que o somatório de métodos laboratoriais é essencial na caracterização das hemoparasitoses em cães, agregando valor e permitindo uma efetiva consolidação do diagnóstico relacionado a essas doenças.

The relationship between ehrlichiosis and the development of hematologic malignancies

Viral and bacterial infections cause chronic inflammation and produce bacterial metabolites that may lead to carcinogenesis. Ehrlichiosis is an intracellular infection that primarily infects white blood cells. Given that infections can lead to cancer, and that Ehrlichia has tropism for white blood cells, it can be deduced that Ehrlichia may cause hematologic malignancies, such as acute leukemia. A prospective study was performed that tested the blood of ten patients with acute leukemia for prior exposure to Ehrlichia. The RT-PCR that was performed did not detect Ehrlichia DNA in any of the ten samples. Therefore, based on this small study, one cannot conclude that Ehrlichia can lead to hematologic malignancies.