WHITE BLOOD CELLS IN URINE

2.WHITE BLOOD CELLS Leukocytes (Pus cells) 

Microscopic appearance

Neutrophils ----Neutrophils or polymorphonuclear neutrophils (PMN) are the most commonly seen leukocytes in the urine. They appear as granular spheres about 10-12 um in diameter. Nuclear segments are fairly visible in a freshly voided urine, but may be lost when cellular degeneration begins. They can be differentiated from red cells by their larger size and granular cytoplasm. Leukocytes are rapidly lysed in hypotonic or alkaline urine. Therefore it is necessary to examine the urinary sediment promptly after collection

Glitter cells-- In a hypotonic urine with specific gravity lower than 1.010, neutrophils swell and appear larger in size. In the dilute urine, the cytoplasmic granules show continuous brownian movement which gives them a glittering appearance.

Other leukocytes Eosinophils, --lymphocytes and monocytes may occasionally appear in urine. Eosinophils are difficult to distinguish from neutrophils in an unstained preparation, but are larger in size and show a bilobed nucleus.

A normal urine may contain a few lymphocytes but are difficult to recognise in an unstained preparation. They appear slightly larger than red cells, and with a single nucleus. 

Mononuclear cells (mono-cytes, histiocytes and macrophages) are larger than neutrophils, with a single nucleus, and abundant, granular and vacuolated cytoplasm. Their identification should be confirmed by staining

Other leukocytes Eosinophils, lymphocytes and monocytes may occasionally appear in urine. Eosinophils are difficult to distinguish from neutrophils in an unstained preparation, but are larger in size and show a bilobed nucleus.

A normal urine may contain a few lymphocytes but are difficult to recognise in an unstained preparation. They appear slightly larger than red cells, and with a single nucleus. Mononuclear cells (mono-cytes, histiocytes and macrophages) are larger than neutrophils, with a single nucleus, and abundant, granular and vacuolated cytoplasm. Their identification should be confirmed by staining

Clinical significance :- A normal urine sediment may contain less than 5 leukocyte per high power field (<5/hpf).

Neutrophils Their presence in urine may be due to various factors:-

(i) Increased number of neutrophils in urine indicates inflammation in the urinary tract. This condition is known as pyuria. Increased neutrophils (pus cells) are generally associated with bacterial infection. 

(ii) Moderate number of pus cells together with pus cell casts may reflect acute or chronic bacterial pyelonephritis, or acute non bacterial glomerulonephritis.

(iii) Calculi at any site in the urinary tract may give rise to increased leukocytes due to mucosal inflammatory reaction.

 (iv) A variety of acute or chronic inflammatory processes, such as cystitis, urethritis, prostatitis or bladder tumours lead to increased number of leukocytes in urine.

 (v) Pyuria with sterile culture may be present in renal tuberculosis, gonococcal urethritis, leptospirosis or antibiotic treatment.

Glitter cells- These are present in pyelonephritis or when the specific gravity of urine is low. 

Eosinophils -Eosinophils may appear in large numbers in urine in allergic interstitial nephritis. Lymphocytes In case of renal transplant rejection, lymphocytes appear in the urine in significant numbers.

Monocytes and histiocytes- These cells in urine are generally due to chronic inflammation or radiation therapy.