Case Studies
Case 3.3 IgA and IgG subclass deficiencies
A 48-year-old man was admitted for investigation of weight loss associated with intermittent diarrhoea. He had a history of pneumonia as a child and again as a young man working abroad. At the age of 33 he had developed chronic sinusitis, with persistent headaches. On examination he was thin but had no signs of malignancy. He had no clubbing and his chest was clear on auscultation. There was no lymphadenopathy and no hepatosplenomegaly. He was not anaemic, had a normal serum albumin and normal liver function tests. Immunological tests are shown in Table C3.3. No infective cause of the intermittent diarrhoea was found; barium enema was normal. Endoscopic examination of his maxillary sinuses showed considerable inflammation and hypertrophy of the mucosa.
A diagnosis of IgA and IgG subclass deficiencies with chronic sinusitis was made. Replacement immunoglobulin was started with weekly infusions initially and subsequently 3 weekly. His sinusitis gradually improved, diarrhoea did not return and he remained infection free for many years.
Table C3.3 Immunological investigations* in Case 3.3.
| Serum immunoglobulins (g/l) |
| IgG |
7.2 |
[6.5-12.0] |
| IgA |
<0.1 |
[0.8-5.0] |
| IgM |
1.2 |
[0.5-2.0] |
| IgG1 |
2.7 |
[3.6-7.3] |
| IgG2 |
3.2 |
[1.4-4.5] |
| IgG3 |
0.1 |
[0.3-1.1] |
| IgG4 |
2.2 |
[0.1-1.0] |
| Antibody activity - post immunization |
| IgG: tetanus toxoid |
Negative [>0.85iu/ml] |
| diphtheria toxoid |
Negative [>0.2iu/ml] |
| pneumococcal polysaccharide |
Inadequate [>80U/ml] |
| Antibody activity - post exposure |
| IgG: Rubella |
Not detectable |
| Measles |
Not detectable |
| Varicella zoster |
Not detectable |
| Blood lymphocyte subpopulations (x109/l) |
| Total lymphocyte count |
2.8 |
[1.5-3.5] |
| T lymphocytes |
|
| CD3 |
2.2 |
[0.9-2.8] |
| CD4 |
1.6 |
[0.6-1.2] |
| CD8 |
0.6 |
[0.4-1.0] |
| B lymphocytes |
|
| CD19 |
0.3 |
[0.2-0.4] |
*Normal adult ranges shown in brackets.
|
