THE STORY BEHIND AUER RODS

Auer rods, as the name goes, is something related to rod like structure.

Yeah, they are rod- shaped crystalline structures, derived from primary granules of myeloid cells. They are characteristically seen in acute myeloid leukemias (AML). They can also be seen in myeloblasts in other conditions like myelodysplastic syndrome, myelodysplastic/myeloproliferative neoplasms. They are named after John Auer.

John Auer was born in Rochester, New york in 1875 and graduated from John Hopkins Medical School in 1902. In April 1903, while John Auer was working in Dr.William Osler’ ward at John Hopkins Hospital, he saw a 21 year old man with fever, severe nose bleed, throat infection, anemia and splenomegaly. His total leucocyte count was 139x 10⁹ g/dl. 92% were immature leukemic cells out of which 6-10 % leukemic cells contained rod-shaped cytoplasmic inclusions.

At first, he saw the wet preparations of the patients blood and noted “refractile rod-like body”. This made him to carefully see the Romanowsky stained blood smears. These rods were 1-6 microns, stained azurophilic, needle like rod forms or spindle forms. Auer took permission from Drs.Osler and Thomas McRae to publish this finding. He actually thought that these inclusions were seen in lymphocytes Later, it was shown that these rod-like structures were seen in myeloid cells.

                                               Thomas McCrae  and John Auer

Controversy in the eponymous name of Auer rods.

Auer is given the credit for his first description and illustration of Auer rods in paper titled ‘Some hitherto undescribed structures found in the large lymphocytes of a case of acute leukemia, published in ‘The American Journal of the Medical Sciences’ in June 1906. 

There is lot of controversy in the naming of Auer rods. But Auer acknowledged that the observations had been mentioned previously, in the preceding year, in an article by Thomas McCrae. McCrae also provided the clinical notes for Auer’s paper and Auer acknowledged him for the same. 

Interestingly, both McCrae and Auer thought that these rod like structures were seen in lymphoblasts.

Some think that Auer rods should be rather be named McCrae- Auer rods.

References:

1.     John Auer and Auer rods; controversies revisited. Leukemia Research 33 (2009) 614–616.

2.    Barbara J Bain. Auer Rods or Mc Crae Rods? Am J Hematol 2011 Aug; 86(8): 689.

3.    Thomas McCrae picture taken from Google images, collections.nlm.nih.gov.

4.    John Auer picture taken from John Auer and Auer rods; controversies revisited. Leukemia Research 33 (2009) 614–616.

                                                                          Written by Dr.Priyavadhana