Distribution of Variant Genotypes of SH-FcγRIIIb in Individuals, as Determined by SfaN1 Digestion of PCR Fragments Amplified With NA2-Specific Primers
| AA . | CA . | ||||
|---|---|---|---|---|---|
| Positive Amplification With Primers Corresponding to . | Pattern of SfaN1 Digestion . | Positive Amplification With Primers Corresponding to . | Pattern of SfaN1 Digestion . | ||
| NA1 + NA2 | CC | 44 (66%) | NA1 + NA2 | CC | 80 (94%) |
| AC | 14 (21%) | AC | 4 (5%) | ||
| AA | 9 (13%) | AA | 1 (1%) | ||
| NA2 only | CC | 36 (64%) | NA2 only | CC | 69 (96%) |
| AC | 15 (26%) | AC | 3 (4%) | ||
| AA | 5 (9%) | AA | 0 (0%) | ||
| χ2 = 1.0 P = .60 | χ2 = .88 P = .64 | ||||
| AA . | CA . | ||||
|---|---|---|---|---|---|
| Positive Amplification With Primers Corresponding to . | Pattern of SfaN1 Digestion . | Positive Amplification With Primers Corresponding to . | Pattern of SfaN1 Digestion . | ||
| NA1 + NA2 | CC | 44 (66%) | NA1 + NA2 | CC | 80 (94%) |
| AC | 14 (21%) | AC | 4 (5%) | ||
| AA | 9 (13%) | AA | 1 (1%) | ||
| NA2 only | CC | 36 (64%) | NA2 only | CC | 69 (96%) |
| AC | 15 (26%) | AC | 3 (4%) | ||
| AA | 5 (9%) | AA | 0 (0%) | ||
| χ2 = 1.0 P = .60 | χ2 = .88 P = .64 | ||||
SfaN1 digestion of amplicon generated with NA2-specific oligonucleotide primers was analyzed by agarose gel; SH-FcγRIIIb can only be detected in individuals in whom a product can be amplified with NA2-specific primers. Digestion by SfaN1 indicates the presence of the SH-FcγRIIIb sequence. Specifically, a nucleotide change at position 266 from C to A results in a change of alanine to aspartic acid at residue 78. Data were analyzed using a 3 × 2 χ2test for heterogeneity with 2 degrees of freedom. Sequence difference at nucleotide position 266: C, reported NA2 sequence; A, SH-FcγRIIIb.