Plasmacyte Heterogeneity of Lame Ducklings

The aim is to describe the array of plasmacytes (PC), cells known as the source of antibody, occurring in the bone marrow (BM) of lame ducklings. The method is by a light microscopic examination of touch preparation slides made from femur samples and stained with Wright-Giemsa. Samples were obtained on site at commercial farms where slide preparations were made; reducing the possibility that observations are technical artifacts. The results: indicate that PC occur in a multitude of sizes, shapes, nuclear/cytoplasmic (N/C) ratios, ploidy, and nuclear and cytoplasmic conditions. Normal PC are illustrated first, followed by atypical forms. Some PC are presented in the context of neighboring BM cells of the granulocyte, erythrocyte, and reticulum cell (histiocyte) series. More than 100 Mott-type PC were measured in a single sample from a 13-day lame duck; and several distinct forms were identified. Size, as measured by their longest axis, varied from 6.1 to 28 μm and it appears to be normally distributed. Moreover, N/C ratios were distributed across a three-fold range (0.3 – 0.9) indicating Mott phenotypes can occur at multiple developmental stages. Motts differed in Russell Body (RB) size, and nuclear condition. A novel Mott type, “orb” form, with partially lysed nuclei is also described. PC were often found in association with giant granulated histiocytes (ggh) and non-granulated giant histiocytes (gh). Other atypical forms are “hand-mirror” PC, trinucleate and binucleate PC resembling cells seen in multiple myeloma (MM) and lymphomas. Collectively these PC variants constitute “reactive plasmatosis” (RP) likely arising as a consequence of the presence of various bacteria including Streptococcus and E. coli. The conclusions: It is demonstrated that RP as occurs in lame ducklings suffering from bacterial infections, provides a unique theater for the study of PC variability. Atypical PC, some resembling neoplastic types, were common in RP BM. The significance of the study relates to the importance of PC in disease and immunity; therefore, these observations should interest those who specialize in these areas. They expand the knowledge of avian plasmacyte morphology.